Theatres, antiseptics, and antibiotics
From Primary Surgery
It is one thing to operate with the chief at your elbow on a patient whose vital functions are being monitored by an expert anaesthetist at the head of the table. It is quite another to be almost alone at midnight, struggling with a patient in shock from a ruptured ectopic pregnancy, as the light fades in and out while a superannuated generator tries to function on adulterated diesel oil. Then is the moment of truth when you realize that an excellent theoretical foundation is not the only thing you need[...] Gerald Hankins, The Shanta Bahwan Hospital, Kathmandu, Nepal
Contents |
The major theatre
Although aseptic surgery has been done in a tent, under a tree, or on a kitchen table, it is safer if it is done in a room which has been designed to preserve the sterility of the surgical field, to make surgical routines easier, and to prevent mistakes. The difficulty with aseptic methods is that they require an autoclave. If you don't have one, we describe an antiseptic method that you can use instead (2.6). You will need two theatres, a major one and a minor septic one (2.2). We are concerned here with the major one.
When you start work in a theatre, look at it carefully. How many of the desirable features that we are about to describe does it have? Is there anything which you could do to make it safer or more efficient?
The operating team should be as small as possible. It consists of: (1) Yourself the surgeon. (2) Your assistant, when you need one. (3) The scrub nurse responsible for the instruments. (4) The circulating nurse to fetch and carry. (5) The anaesthetist. (6) His assistant, if he has one. Two other people are important: (a) The theatre charge nurse responsible for organizing the theatre, and who in a smaller hospital will take a turn at being on call. And (b) the theatre dresser' who is less educated, but, unlike the nurses who come and go, has spent his whole career in the theatre, and so knows its routines and where things are.
In an emergency roles (2) and (3) can be combined in an efficient nurse or medical assistant, and so can roles (4) and (6). The first three members of the team are sterile', the last three are not. An important part of the drill is to prevent the last three from compromising the sterility of the first three, and the surgical field.
Two zones in the theatre ensure this. There is : (1) A sterile zone which includes the operation site, the first three members of the team, and that part of the theatre immediately around them. (2) An unsterile zone which usually includes the head end of the patient, and the rest of the theatre. The last three members of the team can move freely in this zone. The patient's entrance and the access to the sluice room are continuous with it. A separate room for scrubbing up is not essential, and it can be done in the theatre in two domestic pattern sinks with draining boards. They should be fitted with elbow taps which are very highly desirable, although you can scrub up from a bucket.
Straightforward physical cleanliness is important. Sophisticated methods are unnecessary. Sluicing the floor between cases, washing the walls weekly and mobile equipment daily will ensure a high enough standard without using antiseptics on the theatre itself. The floor is important. The most dangerous sources of infection are pus and excreta from the patients, which must be cleared away between every operation, and must not be allowed to contaminate the theatre. To make this easier, it should have a terrazzo floor, but a smooth concrete finish is almost as good and much cheaper. To make it easier to wash down, it should have a 1:1000 slope towards an open channel along the foot of the wall at the unsterile end of the theatre. This channel should have a plugged outlet leading directly outside to an open gulley. Fit a sparge pipe to the wall at the sterile end 150 mm above the floor, so that the whole floor can be flooded by turning a tap. A little dust on trolley wheels or shoes, or from open windows, is less dangerous than is generally believed.
The walls of the theatre should be smooth, but they need not be tiled. A sand and cement backwash application painted with one coat of emulsion and two coats of eggshell gloss is adequate. Gloss paint is satisfactory for the walls, and the fewer the doors, sills, ledges, crevices, mouldings, architraves, and window boards, the better. Every time a door is opened, dust from the floor is whirled into the room. There is no need for a door between the changing rooms and the theatre. A door is only needed between the sluice and sterilizing room, if these rooms will be used when the theatre is not.
The ceiling should be at least 3.5 metres high and the roof timbers solid enough to support an operating light. It should also have a pair of 2 metre fluorescent tubes.
The ambient level of illumination should be high, so make the windows big enough. They may enable most operations to be done by daylight. There should be a window of 5 m['2] at the head and the foot ends, facing north and south shaded by a roof overhang of at least 800 mm. Even better are windows on three sides. Fit ordinary low windows, and frost only the panes below eye level, so that the staff can look out (which improves morale), but that anyone looking in can only see their heads, not the patient. In the tropics avoid windows in the roof.
The preparation room should lead off the theatre. A big one is desirable, because it needs to contain two autoclaves, a big and a small sterilizer, sterile packs, instrument cupboards and space to lay out instrument trolleys. Ideally, it should be 64 m['2] and serve two theatres. About 25 m['2] is the absolute minimum, with a terrazzo shelf round most of two walls, a sink, a draining board, a single vertical autoclave (preferably two), a large boiling water sterilizer standing on the floor, and a small one on the bench.
OPERATING TABLE, simple pattern, (NES) each $240, one only. At the time of writing this table has to be made to order. The minimum requirements of an operating table are that: (1) You must be able to tilt the patient's head down rapidly for the Trendelenburg position, and if he vomits (A 3.1, A 16.2). (2) You should be able to adjust its height. This table does these things at a fraction of the cost of the standard hydraulic ones, which need careful maintenance, and are useless when their hydraulic seals perish. However, if a simple general purpose hydraulic table is well maintained, it lasts a long time. A really sophisticated one can cost as much as the entire building of the theatre. A dirty table is a menace, so make sure yours is kept clean.
If the head of your table does not tilt head down, get one that does. Meanwhile, in an emergency, you can put a low stool under the bar at its foot. If it does not tilt from side to side, make a wooden wedge to fit under the mattress. If it does not have a kidney bridge and you want one (most surgeons don't use them now), use folded plastic covered pillows.
Locally made Chogoria' supports (15-3) are a useful addition to a standard table. They are made of two suitably bent pieces of pipe which fit into the holes for ordinary stirrups and keep the patient's hips widely abducted, and his hips and knees moderately flexed, so that his lower legs are horizontal. His legs rest on boards attached to these pipes. These supports are more comfortable than stirrups and are particularly useful for such operations as tubal ligation.
ALTERNATIVE OPERATING TABLE, as Seward minor (SEW), or equivalent, one only. This is slightly more versatile and considerably more expensive than the table above.
MATTRESS, for operating table, (a) one only, with (b) three mackintosh covers only. A dirty mattress is a potentially serious source of infection. So swab the cover after each patient, and replace it regularly.
ARM BOARD, for operating table, locally made, one only. This is simply a piece of hardwood about 20[mu]120[mu]1000 mm, which you push under the mattress to rest the patient's arm on, when you want to inject it.
STOOL, operating, adjustable for height, local manufacture, two only. If you do much operating, a chair with a padded seat, wheels, and a back greatly reduces fatigue.
LIGHT, operating theatre, simple pattern, preferably with sockets to take bayonet or screw fitting domestic pattern light bulbs, in addition to special bulbs, state voltage, one only. Most operating theatre lights take bulbs which are irreplaceable locally, and may cost $70 each, so find out what bulbs your light takes, and try to keep at least three spares. Record their specification and catalogue number somewhere on the lamp casing. When new lights are ordered, they should have fittings that can, if necessary, take ordinary domestic bulbs.
CLOCK, wall, electric, with second hand, one only. This is essential, you must have a proper awareness of time, especially when you apply a tourniquet (3-11), and without a clock you can readily forget it. The instructions given here for controlling bleeding by applying pressure sometimes tell you to wait 5 minutes by the clock.
SOLAR PANEL, charger, and battery, one only of each. A single solar panel will collect a useful quantity of electricity and enable you to light two wards in the evenings.
BATTERY CHARGER for the common sizes of rechargeable dry batteries, and five rechargeable batteries of each size, one outfit only. This will enable you to recharge batteries for your torches and laryngoscopes etc.
INSTRUMENT CABINET glass door, sides and shelves, 1300[mu]600[mu]400 mm, local manufacture, one only.
X-RAY VIEWING BOX, standard pattern, local manufacture, one only.
TROLLEY, instrument, without guard rail, with two stainless steel shelves, antistatic rubber castors, (a) 600[mu]450 mm, three only. (b) 900[mu]450 mm, one only. Glass shelves ultimately break, so stainless steel ones are better. A larger table will make it easier to lay up for larger cases, especially orthopaedic ones.
STAND, solution, with antistatic rubber tyred castors, complete with two 350 mm stainless steel bowls, side by side, one only. Put water in one bowl, and use the other for spare instruments and the sucker. The bowls can be sterilized in the autoclave or in a boiling water sterilizer.
DRIP stands, telescopic, two only Or, less satisfactorily, use long wire hooks suspended from the ceiling near the head of the table. Hooks for drips sticking out from the wall are useful above some beds in the wards.
Mein P, and Jorgenson T, Design for Medical Buildings', AMREF, Box 30125, Nairobi.
The minor theatre
A minor theatre for septic cases will help to maintain the sterility of the major theatre. Use it for draining all abscesses, for skin grafting and for the closed reduction of fractures. It will need a simple operating table which tips (A 3- 1), and a second set of basic anaesthetic equipment, including especially a sucker and the equipment for resuscitation. It will also need two minor sets (4.12), three incision and drainage sets, and a set for drilling for osteomyelitis. If possible the minor theatre should have its own instruments and not be supplied from the main one.
Health centre theatres
The focus of this system of surgery is the district hospital where, inevitably, most of the surgery that is needed in the developing world has to be done (1-6). There is however some surgery that can and should be done by medical assistants in a health centre. This has been described by Peter Bewes in the manual described below. Surgery can also be done in a health centre by a visiting surgeon' and is particularly valuable for tubal ligation (15.4).
Bewes P, Surgery', TALC Teaching Aids at Low Cost, The Institute of Child Health, 30 Guilford Street, London WC1N 1EH. Also from AMREF Box 30125 Nairobi.
Aseptic theatre technique
In order of importance, the most serious sources of infection in a theatre are bacteria from: (1) The pus and excreta left behind by previous patients, especially on its equipment or towels, etc. (3) The clothes, hands, skin, mouths, or perineums of the staff; the bacteria on them may have been derived from other patients. (4) The patient himself.
Minimize the risk of infection by: (1) Following the design rules in the previous section as far as you can. (2) Keeping the theatre as clean as possible, so that the pus and excreta of previous patients are removed. (3) Making sure that the autoclaving is done conscientiously. (4) Following the rules about the indications for operating, the timing of operations, wound closure (54.2), and careful tissue handling. (5) Creating and maintaining the sterile zone in Fig. 2-1.
This sterile zone has to be created anew for each patient in a theatre in which the risk of infection has been reduced as much as possible. Its creation starts when a nurse swabs the top of a trolley with antiseptic, puts two sterile towels on it and lays out sterile gowns and gloves. The sterile zone grows as the surgeon, his assistant and the scrub nurse put on their gowns. The operation site joins the sterile zone as it is prepared with an antiseptic solution and draped. Thereafter, nothing which is contaminated must touch anything in this zone until the end of the operation. If the technique of the team is poor, the sterile zone becomes smaller and smaller as the operation proceeds.
WOUND SEPSIS AND THE ART OF SURGERY Professor IJP Loefler speaks in the reference given below: In summary, I believe that regard for tissue is the foremost of our priorities. Let us strive to become first class surgeons, and let us train considerate disciplined theatre staff. Let us have plenty of soap and water, or some not too corrosive detergent. We do need sterilizers and autoclaves. We need well ventilated rooms which are light and easy to clean, and where the number of additional items is kept low. We should don theatre attire, should indeed change frequently, and should certainly change our masks. Gloves are important though not indispensable. Use sharp knives, few instruments and keep things neat and clean. Do not bury undue amounts of biologically irritating material in the tissues. Beware of haematomas and lymph collections. Use suction drains frequently. Use delayed primary closure where this is indicated (54.4). In the wounds you make yourself bring the skin edges together carefully so that the wound is sealed in a few hours. Hydrate your patient, and do not oversedate him. Avoid stasis by elevation and movement. Use dressings sparingly, and observe the wound. If you find a haematoma and evacuate it speedily you will prevent sepsis. Loefler IJP, Wound sepsis and the art of surgery', Proceedings of the Association of Surgeons of East Africa 1979;2:172-180 SUITS, theatre, cotton, with short sleeved shirt, and long trousers, assorted sizes, local manufacture, 30 only. The purpose of these is to make sure that nobody enters the theatre in his ordinary clothes, or in clothes which he has worn elsewhere in the hospital. Everyone entering a theatre should put on a theatre suit in the changing room. These suits should be laundered, and if possible ironed, but need not normally be sterilized each time they are used, unless they have been used for septic cases.
CLOGS, assorted sizes, ten pairs only. Rubber boots are outmoded; sandals are less easy to keep clean and less comfortable than clogs. Change into them at the barrier between the theatre and the rest of the hospital.
APRONS, macintosh, assorted sizes, local manufacture, eight only. These protect the suits and are worn under a theatre gown. If they are merely hung up in the changing room after use, they become progressively more contaminated and more dangerous. So make sure that they are at least washed and regularly swabbed down with an antiseptic solution, and are always swabbed after septic cases. Keep two for special clean cases only.
CAPS, cotton, 30 only. Put on a cap before you enter the theatre, and make sure it completely covers your hair.
MASKS, theatre, 100 only. Make these from 4 layers of muslin. A mask must cover your nose; if it fogs your glasses, arrange its top edge, so that your breath does not drift upwards, or, rub your glasses with ordinary soap and polish them. Use a new mask for each major case.
GOWNS, cotton, 50 only. These should go right round the wearer and cover his back. Before sterilisation they must always be folded so that the inner surface on the wearer is exposed to the outside in the drum.
GLOVES, operating, reusable, (a) Size 6, 20 pairs. (b) Size 6[1/2], 40 pairs. (c) Size 7, 40 pairs. (d) Size 7[1/2], 40 pairs. (e) Size 8, 20 pairs only. Remember that gloves are designed to protect the surgeon as much as the patient. The type of gloves you buy is critically important, and so is the relative number of the various sizes. They must be capable of being resterilized many times. Most nurses wear size 6[1/2] and most doctors size 7 or 7[1/2]. Pack each pair in a cloth or paper envelope, one glove on each side with its cuff turned outwards. Gloves are more useful to protect you and the next patient, than the patient you are actually operating on. If necessary, you can operate without gloves, so don't let the absence of gloves prevent you doing a life-saving operation.
GLOVES industrial, three pairs only. These are useful for picking up hot objects, and used on the correct indications will save many pairs of surgical gloves.
GLOVE POWDER, absorbable, 3 kg only. Don't use starch or talc because it causes granulomas. Put the powder into little gauze bags which can be used as shakers, or use small pieces of paper.
SOAP, hexachlorophene, carbolic, 50 tablets only. If necessary, the cheapest soap that does not irritate the skin will do.
BRUSHES, nylon, nesting, autoclavable, 50 only. Autoclave several of these each operating day and store them between cases in a bowl of antiseptic solution. They will last longer if you merely keep them clean and immerse them in an antiseptic solution.
TOWELS, cotton, green, theatre. (a) Hand towels 25 cm square, 100 only. (b) Theatre drapes 100[mu]75 cm, 100 only. (c) Abdominal sheets, ten only. An abdominal sheet covers a patient completely from head to foot and has a slit in it through which the operation is done. The upper end acts as a guard which keeps the patient's head and the anaesthetist out of the operative field.
OTHER SUPPLIES, (1) Pyjamas and pyjama trousers, 20 only. (2) Dresses, 20 only. (3) Macintosh drapes, 75[mu]100 cm, 20 only. (4) Squeegees, two only. (5) Bucket and mop, three only.
ASEPTIC TECHNIQUE ENTERING THE THEATRE. Anyone entering the theatre must change, in the changing room, into clogs or sandals and into a suit. Decide which operations need gowns, gloves or masks.
SCRUBBING UP. Adjust the elbow taps to deliver water at a comfortable temperature. In most tropical countries only a cold water tap is necessary. Wet your hands, apply a little soap or detergent, and work up a good lather. Rub your hands and forearms to 5 cm above your elbows for one complete minute. Wash your forearms.
Then take a sterile brush and put soap on it. Scrub the lateral side of your left thumb, then its medial side, then the lateral and medial aspects of each successive finger. Scrub your nails, and then the back and front of your left hand. Do the same with your right hand. Scrub for 5 minutes in all.
Alternatively, some surgeons merely scrub their nails, unless they have got ingrained dirt from some other dirty task, and then thoroughly wash their hands and arms to their elbows.
Rinse the suds from your hands while holding them higher than your elbows. Turn off the taps with your elbows.
Dry your hands with a sterile towel before you put on a sterile gown. Dry your hands first, then your forearms. Grasp the folded towel with the fingers of both hands, then step clear, so that you don't touch anything with the open towel. Blot your hands on one corner, then dry your forearms. Try not to bring a wet (unsterile) part of the towel back to a dry area.
GOWNING. Hold the gown away from your body, high enough to be well above the floor. Allow it to drop open, put your arms into the arm holes while keeping your arms extended. Then flex your elbows and abduct your arms. Wait for the circulating nurse to help you. She will grasp the inner sides of the gown at each shoulder and pull them over your shoulders.
GLOVING. Dust your hands with powder and rub them together to spread it. Be careful to touch only the inner surface of the gloves. Grasp the palmar aspect of the turned down cuff of a glove, and pull it on to your opposite hand. Leave its cuff for the moment.
Put the fingers of your already gloved hand under the inverted cuff of the other glove, and pull it on to your bare hand. It is a good routine to wash your gloved hands in sterile water to remove the powder.
Now help the next person who has gowned on with their gloves.
If you TEAR OR CONTAMINATE A GLOVE during an operation, remove it. Grasp its cuff from the outside, and pull it down over your palm. Ideally, don't remove the glove yourself, because you will contaminate your other hand. Instead, hold out your hand to the circulating nurse, who will grasp the edge of the cuff and pull it off. In practice most circulating nurses are too nervous to do this, so you will have to do it yourself by touching the outer side of the cuff only.
THE OPERATION SITE SHAVING. The operation site should be socially clean before the operation, and you may have to check this. There is usually no need to shave a patient. If you shave him, do so on the morning of the operation, or as part of the operation. If you shave him a day or two before, minute abrasions in his skin will become infected and the risk of wound infection will increase. If hair is going to get in the way, all you need to do is to clip it short immediately before the operation.
PREPARATION. Do this as soon as the patient is anaesthetized. Start with a soapy solution, and follow this with spirit. Or, better, if there is a low sensitivity to iodine in the community (as in most of Africa), use alcoholic iodine (2.5). Take a sterile swab on a holder, start in the middle of the operation site, and work outwards. Discard both swab and holder, and repeat the process with a second swab (some surgeons use a third). The spirit will evaporate to leave the skin dry. Some surgeons consider this is over-elaborate, and merely use a single application of iodine.
Be sure to prepare a wide enough area of skin. In an abdominal operation this should extend from the patient's nipple line to below his groin.
DRAPING. Wait until he is anaesthetized. Place the first towel across the lower end of the operation site. Place another across its nearer edge. Apply a towel clip at their intersection. Place another towel across the opposite edge of the site, and finally one across its upper edge. Clip them at their intersections. If necessary, grip his skin with the clips, or secure the towels with a stitch. Alternatively, drape him with two longitudinal towels clipped at each end, with a towel above and below. Then, in an abdominal operation, cover his whole abdomen with an abdominal sheet with a narrow quadrangular hole in it.
If important areas near the surgeon become contaminated, cover them with fresh sterile towels.
SWABS AND PACKS. Use 10 cm gauze squares on spongeholding forceps (swabs on sticks'). You will also need abdominal packs.
CLEANING THE THEATRE. Clean it thoroughly after each day's list, and completely every week.
CLEANING INSTRUMENTS. Use an old nail brush. Open hinged instruments fully, scrub them, and take special care to clean their jaws and serrations.
DIFFICULTIES [s7]WITH ASEPTIC METHODS If you have NO GLOVES or very few gloves, scrub up and then rinse your hands and arms in alcoholic chlorhexidine (2.6). The alcohol will dehydrate your skin. You can reduce this by adding 1% glycerol to the solution. Unfortunately, although antiseptics may help to protect the patient, they are less effective in protecting you from AIDS (28a.4).
If you have NO DRAPES OR GOWNS or very few of them, use plastic sheets and aprons and soak them in an antiseptic solution (2.6).
Boiling and autoclaving
Sterilization is the total destruction of all forms of life, including bacterial spores. It is best done with heat, either dry heat in an oven, or steam under pressure in an autoclave. Processes (usually chemical) which do not destroy spores are termed disinfection'. Some of the most important agents to be removed by disinfection are HIV and HBV (hepatitis virus B). All the disinfectants described in Section 2.5 will do this if used as directed. The most suitable one for many purposes is hypochlorite, which is described in Chapter 28a.
The basis of aseptic surgery is to kill all micro-organisms on all instruments and dressings, preferably by exposure to steam under pressure. If this is impractical, immersion in boiling water for 10 minutes at sea level will kill all viruses and all vegetative bacteria, but not spores, particularly those of tetanus and gas gangrene. A boiling water sterilizer' is therefore badly named. At a height of 3000 metres water boils at 90[de]C and is much less effective.
Steam is the gaseous form of water. If it is to sterilize effectively, which means killing all spores: (1) It must be at an appropriate temperature (which implies an appropriate pressure). (2) It must be saturated with water. (3) It must not be mixed with air, so it must displace all the air in the chamber of the autoclave. And, (4) it must reach all parts of the load. If it contains droplets of water, it will soak into porous materials. If, on the other hand, it is superheated and therefore too dry, it will be less effective as a sterilizing agent. If air is mixed with steam: (1) the temperature of the mixture at a given pressure will be lower, (2) it will penetrate less well into porous materials, (3) the air may separate as a lower, cooler layer in the bottom of the chamber, so that the contents are not sterilized. If no air is discharged, the bottom of the chamber may be much cooler than the top.
As soon as the chamber of an autoclave is full of steam at the desired temperature and pressure, it must be held there for a critical time[md]the holding time. The standard holding time is 15 minutes, at 121[de]C, but you will need to vary it as described below. This temperature is reached at a pressure of about 1 kg/cm['2] (15 pounds per square inch). An easy minimum figure to remember is 1 kg per square cm for 15 minutes' (15 pounds for 15 minutes'). If your autoclave is rated to 1.3 kgcm['2], you can shorten the sterilizing time to 10 minutes. Here we only discuss the simpler forms of autoclave; high vacuum autoclaves are beyond the scope of this manual.
Single walled autoclaves are strong metal chambers with water in the bottom, like large pressure cookers. They have several disadvantages: (1) The air in the chamber is removed by steam rising from the bottom. This is inefficient, so that an undesirable quantity of air remains. (2) They don't have thermometers at the bottom of the chamber, so you never know what the temperature there is. (3) The load remains moist after sterilization, which can be dangerous, because bacteria can more easily enter through moist wrappings.
Double walled autoclaves can be vertical, but are much better horizontal. They should either have an effective prevacuum, or a pulsing system (neither described here), or rely entirely on gravity to displace the air. A partial prevacuum at the start of the sterilizing cycle (which used to be the practice in some older autoclaves) causes turbulence when air is admitted, so that the gravity displacement of air cannot take place satisfactorily.
Steam is generated in, or admitted to, a jacket round the chamber, rather than in the chamber itself. This jacket keeps the walls of the chamber hot, which prevents condensation and helps to dry the load. Steam enters the chamber through a pipe at the top and displaces the air it contains. Air, condensate, and excess steam escape through a pipe at the bottom. This pipe has a thermometer in it to record the temperature in the bottom of the autoclave. In some autoclaves a water pump, which works on the same principle as an ordinary laboratory water pump, sucks out some of the steam afterwards (postvacuum). There is also a means of admitting sterile air to break the vacuum at the end of the cycle.
The drain at the bottom of the chamber should have a near- to-steam trap', which will alllow the discharge of condensate and air, and will close automatically when they have been discharged, and the trap meets live steam, thus avoiding the need to close valve 13 in Fig 2-7 manually, which could spoil sterilization.
The thermometer records the temperature in the chamber drain, which is the coolest part of the autoclave. When this reaches the operating temperature, the timing of sterilization can begin.
More sophisticated autoclaves have better pumps, a recording thermometer, a thermocouple to measure the temperature of the load, and an automatic control system.
Inadequate sterilization is an important cause of wound sepsis in poorly maintained theatres. There are many pitfalls. Start by inspecting your equipment and taking an interest in it. Read the maker's instructions carefully, and make sure: (1) That it has been properly fitted and tested. For example, if a water ejector pump is fitted, it is likely to need a water pressure of 1.5 kg/cm['2]. (2) That all the staff who use it understand how it works, and how to use it effectively. They must realize the importance of packing the drums loosely, the need to discharge the air, and the correct holding time.
Most of the hospitals for which we write don't have piped steam supplies. If so, you will will have to use a vertical autoclave. You will probably have electicity, but it is likely to be unreliable, so you will want one which can be heated by electricity, or by putting a kerosine pressure heater or a charcoal stove under it. Unfortunately, we have not been able to find such an all-fuels' autoclave, but Jacob White (WHI, see Appendix B), will consider making one if the demand is high enough (write to them). If you raise an ordinary vertical electric autoclave on bricks so that you can get a pressure heater under it, you are likely to harm the electric cables to the elements. Unfortunately, there is no WHO specification for a district hospital autoclave, as there is for an X-ray machine (1.13).
AUTOCLAVE, horizontal, downward displacement with near-to- steam trap in the chamber drain, post vacuum, six spare gaskets, three spare bellows for the steam trap, and a triple set of other spares, one outfit only. If you have a steam supply, this is the autoclave you need. Horizontal autoclaves are easier to use, but are more expensive. You will need a standby, in case the electricity fails, so you should have an autoclave that can be heated by kerosene or gas somewhere in the hospital (see below).
Alternatively, AUTOCLAVE, vertical, downward displacement, 350 mm, 2[1/2] drum, electric, 6 kw, state voltage, manual operation, with six spare elements, six spare gaskets, and a triple set of other spares as necessary, one outfit only.
AUTOCLAVE, vertical, 350 mm, 2[1/2] drum, for heating by kerosene or gas, manual operation, with six spare gaskets, and a triple set of spares as necessary, one outfit only. This is for use in emergency, see above.
AUTOCLAVE, vertical, pressure cooker', 47 l, UNICEF, as (WIS) No.1941, one only (optional). This is UNICEF's large autoclave which can be heated on a stove and has a machined lid so that it needs no gaskets. It is large enough for 5 litres of intravenous solution, or one laparotomy pack. It is a useful standby. It has an air exhaust tube which leads from the exhaust port to the bottom of the sterilizer. If you use it, you can start timing as soon as steam comes from the exhaust.
HEATER, kerosene, pressure, Primus' pattern or equivalent, four burners, with 20 spare jets, prickers and washers, two only. Use this to heat the autoclave, either regularly or in an emergency.
TUBES, Browne's, for testing autoclaves, Type one (black spot), for use with ordinary steam sterilizers below 126[de]C, 100 tubes only. These change colour on the basis of time and temperature, and are reliable, provided that there is not a long drying cycle, when prolonged heat in a jacketed sterilizer could change their colour.
Alternatively, CARDS, autoclave testing, ATI Steam-clox' 25 rolls only. This brand of tape changes colour on the basis of moisture and temperature, to indicate that something has been autoclaved. Most other brands of autoclave tape are only suitable for high pre-vacuum autoclaves, not for the downward displacement ones described here. Another alternative is Diack Controls', a pellet in a glass tube which melts at 121 or 126[de]C.
DRUMS, deep, 340[mu]230 mm, ten only. This is the standard size of drum.
DRUMS, shallow, 340[mu]120 mm, ten only. These are half- size drums. You may have difficulty getting drums because they are no longer used in the developed world. If you are short of drums, sterilize your equipment in packs, covered by two layers of towelling and preferably an outer layer of paper. If you are sterilizing without paper, use all equipment warm straight from the autoclave.
DRESSING BOXES, stainless steel, with hinged lid and perforated sliding shutters at front and back, 250[mu]200[mu]150,,,,mm, three only. Use these for sterilizing gloves and dressings.
TRAYS, dressing, without lids, stainless steel, 275[mu]320[mu]50 mm, 20 only. Use these to prepare sterile sets for the wards. Boil a tray and the instruments, lay a sterile towel on the tray, put the instruments on it and fold it over them. Better, autoclave the tray.
STERILIZER, boiling water, electric: (a) Bowl sterilizer', 450[mu]350[mu]380 mm, with counterbalanced lid, 6 kW, with six spare elements, state voltage, one only. (b) Instrument sterilizer, 350[mu]160[mu]120 mm, 1.2 kW, with six spare elements, state voltage, one only. One of these is for trays and bowls, and the other for instruments. Keep them both in the preparation room. Never try to sterilize anything contaminated with faeces with boiling water in a sterilizer[md]it does not destroy spores.
FORCEPS, sterilizer, Cheatle's, 267 mm, UNIPAC 0735200, two only.
FORCEPS, sterilizer, Cheatle's extra large, 279 mm, complete with can of appropriate size for antiseptic fluid, two only. These are useful for bowls and utensils, and will also pick up small objects.
FORCEPS, bowl sterilizing, Harrison's double jawed, complete with can of appropriate size for antiseptic fluid, one only. Autoclave these and Cheatle's forceps and their cans after each day's use, then fill them with fresh antiseptic fluid.
STERILIZING WITH MOIST HEAT BOILING WATER Microbes are much more easily killed if instruments are clean, so make sure that everything is cleaned before it is sterilized. Remove instruments from boiling water with long- handled Cheatle's forceps which have been in saponated cresol (Lysol') up to their handles. If you are not wearing sterile gloves, make sure you let the instruments dry. If you use them wet, bacteria from your hands may flow down from your fingers in drops of water.
PACKING [s7]ANY AUTOCLAVE Sterilization is impaired by anything which hinders the removal of air, so: (1) Arrange the contents loosely; a drum which can only be closed with difficulty is grossly overpacked. Place the contents so that air can readily be displaced downwards[md]the principles are the same in horizontal and vertical autoclaves. To avoid air pockets, interleave sheets of macintosh or jaconet with some permeable fabric, so that no two surfaces of the non-permeable material are in contact.
A SIMPLE AUTOCLAVE [s7](or pressure cooker) Make sure there is enough water in the bottom of the autoclave. Insert the drums to be sterilized, and turn on the heater. See that the discharge tap is open, and then screw down the lid. As the water boils the steam will rise and carry away the air in the autoclave.
CAUTION ! Let the air and the steam escape freely until there is no more air in the autoclave, usually about 10 minutes. To test this lead a rubber tube from the discharge tap into a bucket of water. When air no longer bubbles to the surface, there is no more air. After some trials you will learn how long to allow for this to happen.
Close the discharge tap. Let the temperature rise until it reaches 121[de]C. The safety valve will open and allow steam to escape.
Now start to measure the holding period and continue this for 15 minutes. Turn off the heater and allow the autoclave to cool, until the pressure gauge records zero pressure. Then open the discharge tap and allow air to enter the autoclave. Remove the load.
CAUTION ! If anything in the load has paper or cloth wrappings, don't allow them to touch anything unsterile, until they have dried, because microbes can penetrate wet paper.
JACKETED AUTOCLAVE Keep the jacket full of steam at 121[de]C all through the working day. Drain the chamber to remove any water that may gather in it.
Load the heated chamber, close the lid, and open valve (13).
STERILIZING. Open valve (14). When the temperature on thermometer (12) has reached the sterilizing temperature (usually 121[de]C), the holding time can start. Close valve (13). If it is letting much steam through, the temperature will not reach 121[de]C, until it is closed. So close it as soon as no further air and condensate come out of the chamber. If you still don't get the temperature you need (usually 121[de]C), open valve (13) for a minute or two and try again (a near-to-steam trap does this automatically). When the temperature has been reached, start timing.
CAUTION ! Don't infer the temperature from the reading of the pressure gauge. This may give you an inaccurate indication of its temperature and is a common cause of sterilization failure.
POSTVACUUM (drying). Open valve (20), then valve (18). Leave them open for 15 or 20 minutes. Close valve (18) then valve (20).
TO BREAK THE VACUUM. Open valve (16).
TESTING AUTOCLAVES If you are using Browne's tubes, put a tube in the centre of the load, with, if possible, one on the outside to show that the autoclave has indeed been switched on!
If you don't have Browne's tubes, put some dry earth in an envelope, autoclave this and then culture it in a bottle or tube of nutrient broth. Spores may be slow to grow, so incubate it for a week. If even this is impossible, some theatre sisters have been known to put an egg in the middle of a drum to see if it is hard boiled!
PARTICULAR PROCEDURES [s7]FOR AUTOCLAVING The following figures are guidelines only and vary with the type of autoclave and the size of the load. They apply to a sterilizing temperature of 121[de]C.
Empty glassware and unwrapped instruments. Sterilizing time 15 minutes, drying 10 minutes.
Wrapped instruments, rubber gloves, tubes and catheters, and sutures being reautoclaved. A common regime is 0.7 kgcm['2] (10 lb per square inch) for 20 minutes.
Fabrics and dressings. Sterilizing time 20 minutes, drying 15 minutes.
Liquids in flasks and bottles. Sterilize 100 ml bottles for 20 minutes, 300 ml bottles for 30 minutes, 500 ml bottles for 35 minutes, 1000 ml bottles for 40 minutes, and 3000 ml bottles for 50 minutes. Switch off the heat and let the autoclave cool down. Don't open it until the pressure is zero, or the bottles may burst. See also the Appendix A in Primary Anaesthesia.
PREVENTIVE MAINTENANCE Follow the maker's instructions carefully.
DIFFICULTIES [s7]WITH DOWNWARD DISPLACEMENT AUTOCLAVES If the TEMPERATURE FALLS below 121[de]C, while the pressure remains at 1 kgcm['2] (15lb), the outlet from the chamber may be blocked, and the chamber full of air. Check it daily.
If you work at HIGH ALTITUDES, for each 1000 feet you are above sea level, increase the time you immerse things in boiling water by 5 minutes, and increase the pressure of your autoclave by 0.03 kg/cm['2] (0.5 lb/inch['2]). Water above 80[de]C will kill all vegetative organisms and viruses; boiling water is still effective at 12,,,,000 feet.
If dressings are WET after autoclaving, the steam is probably wet, due to: (1) inadequate lagging of the steam supply pipe, or (2) inadequate tapping of condensate.
If you have reason to suspect IMPERFECT STERILIZATION, run the tests above. Also check that: (1) The drums are packed properly. (2) The correct temperature and sterilizing times are used. (3) The chamber drain is not blocked. (4) The drums are not being recontaminated after sterilization.
Disinfectants and antiseptics
Although heat is the best way of killing micro-organisms, you will have to use chemicals to kill them on a patient's skin, or on anything which heat might harm, such as drains or some suture materials. Heat destroys a cutting edge, so store your scissors in a chemical solution which will destroy bacteria. Classically, these chemicals are either antiseptics, which are safe to use on the surfaces of the body, or disinfectants, which are not. In practice, the distinction is not precise, and the only substances in the list below which cannot be applied to the body are saponated cresol ('Lysol'), formalin, and glutaraldehyde. There is an optimum antiseptic for each purpose, so try to use the right one. Disinfectants have serious limitations and only work when the object they are disinfecting is clean - they are ineffective in the presence of blood or pus. So wash scissors and fine instruments carefully before you store them in an antiseptic solution. If possible, drains and other heavily contaminated pieces of equipment should be boiled or autoclaved after washing and before being immersed in these solutions. Afterwards, wash them well in sterile water before you use them. Catheters and tubes, etc., deteriorate in antiseptic solutions and are better autoclaved before use. Avoid cetrimide; it is mainly a detergent and chlorhexidine is better.
IODINE, tincture USP, one litre only. This is the best skin antiseptic. If necessary, make it by mixing iodine 2 g (if necessary 1 g), sodium iodide 2.4 g, spirit 50 ml and water 50 ml. Tincture of iodine readily evaporates and becomes concentrated; if it does, dilute it. It is still effective and is more economical when it is diluted with spirit until it is a light brown colour.
CHLORHEXIDINE gluconate solution BP ('Hibitane'), five litres only. Both chlorhexidine and cetrimide have so little effect on Pseudomonas that cetrimide can be used to select it from mixed cultures. Fortunately, spirit kills Pseudomonas, so chlorhexidine should be made up in 70% spirit.
GLUTARALDEHYDE concentrate 50% w/w in water, five litres only. It is related chemically to formaldehyde but is less irritant. It is less stable but more active when buffered to pH 7.5 to 8 as in 'Cidex'. Used as a 2% alkaline buffered solution, glutaraldehyde comes nearest to being a chemical sterilant. It disinfects in 10 minutes, but it needs 10 hours to kill spores. It is very irritant, so keep it away from skin.
CRESOL and soap solution BP ('Lysol'), or some other phenolic antiseptic, ten litres only. Use this for disinfecting the tops of theatre trolleys and the floor, etc. Don't apply it to the skin. The concentration of phenolic antiseptics is important. Use them at a a concentration of 1% w/v active phenols. If solutions are too dilute bacteria grow in them.
DRESSING TRAYS, stainless steel, with lids, (a) 250 × 200 × 50 mm, six only. (b) 350 × 300 × 50 mm, three only. Fill the smaller trays with chlorhexidine solution or spirit. Use separate trays for sutures and needles, rubber drains, and dental needles and equipment.
SODIUM NITRITE TABLETS, 100 g. Alternatively, SODIUM NITRITE POWDER, 100 g. This is not an antiseptic, but a 0.4% solution of it in an antiseptic solution will stop steel instruments rusting.
ANTISEPTICS AND DISINFECTANTS
SKIN. Any alcoholic solution will do. Alcoholic iodine is best: use it routinely, except in children, on the scrotum, and in allergic patients. 0.5% chlorhexidine in spirit is a less satisfactory alternative. Apply it to the skin after removing all traces of soap.
WOUNDS. There is no substitute for a scrubbing brush, plenty of water from a jug, and a thorough surgical toilet (54.1). Chlorhexidine is useful for cleaning the skin round a wound.
INSTRUMENTS, SUTURE MATERIALS, AND DRAINS. The following agents are effective against HIV and HBV, in addition to the classical pathogens. (1) 2% alkaline buffered glutaral-dehyde is the best. (2) 5% formalin in 70% spirit. (2) A 0.5% solution of chlorhexidine in 70% spirit with 0.5% sodium nitrite. (This is in terms of the active agent.) (4) Plain 70% spirit. Ten minutes is the absolute minimum time in these solutions, provided instruments are scrupulously clean, 24 hours is safer. Ideally, nothing should be considered 'sterilized' until it has been immersed for 24 hours. Wash all equipment well before using it. CAUTION! (1) Except for glutaraldehyde (which can be used for 14 to 28 days depending on the brand) make these solutions up freshly every week, and keep them covered to prevent the alcohol evaporating. (2) A 'wipe' is not nearly as good as a soak!
Antiseptic surgery
This used to be standard practice before aseptic methods made it obsolete. But it may still be useful when power supplies have failed or your autoclave breaks, or an important operation has to be done in some remote place.
Aim to sterilize everything coming into contact with the wound by soaking it for a sufficient time in an antiseptic solution. Unfortunately: (1) An antiseptic solution leaves everything wet. (2) Sterilization is slow so that you may only be able to do one operation at a time. (3) Wide areas of the body are exposed to the antiseptic, which causes much exudation from the wound. Even so, antiseptic surgery is simple, and makes many kinds of operation possible. If necessary, you can combine antiseptic and aseptic methods, and sterilize smaller instruments in a pressure cooker. Chlorhexidine is the most practical antiseptic, but is far from perfect. The methods below are mostly those used by JF Dick working on the slopes of Mount Everest. Here is his account.
ANTISEPTIC SURGERY UNDER ADVERSE CONDITIONS. The only means of access to our hospital at present is by walking over the mountains for a week. All supplies have to be carried in by porters who take two weeks for the journey. For the first two and a half years, we worked in a traditional Nepali house with a thatched roof and a floor made of mud and cow dung. In it we did over 100 operations by the antiseptic method, without serious mishap. Later, limited space became available, so that although we enjoyed the advantages of tap water, a concrete floor, a clean ceiling, and adequate window ventilation, we still had to operate on a light outpatient type of table and in the same room in which the outpatients received all their medicines, injections, dressings, incisions, and dental extractions. We almost always used epidural or local anaesthesia. Dick JF, Antiseptic surgery', Lancet 1966;ii:900.
ANTISEPTIC SURGERY ANTISEPTIC SOLUTIONS. Use chlorhexidine 5% concentrate to make two solutions: (1) A weak solution of 1/2000 of the active agent in water. Use this for soaking towels, etc. (2) A strong solution for instruments, as described above (2.5). Make up small quantities of solutions frequently, make them up hot, and clean out the containers well between batches.
STERILIZING' EQUIPMENT AND DRAPES. Soak everything which will come into contact with the wound in one of these solutions for at least 30 minutes. Soak sutures and gloves in this solution overnight. Use monofilament (4.6) for ligatures and sutures, and the minimum number of simple instruments.
The most appropriate drape, for a tubal ligation, for example, may be a single solution soaked plastic sheet long enough, and wide enough, to cover the whole patient, with a hole in the middle through which to operate. If you have two such drapes, one can be in use while the the other is being soaked in a flat container of solution.
CAUTION ! Don't use syringes and needles soaked in antiseptic to give a subarachnoid or epidural anaesthetic.
PERIOPERATIVE ANTIBIOTICS for routine use in antiseptic surgery. Some operators have given their patients 1 g of chloramphenicol intravenously immediately before the operation. This is questionable practice, but if you are going to try to use antibiotics prophylactically, this is the logical way to use them (2.7).
WHILE OPERATING, Treat the patient's skin with the solution for at least five minutes before the operation.
Wash your hands as usual and put on the wet gloves. If you are not using gloves, soak your hands in solution for five minutes.
Wring out the soaked drapes as dry as you can, and apply them as near as possible to the operation site. Clean the patient's skin with the same solution. If there is a danger that he might get cold, cover him with a dry blanket in a plastic sheet, and put this between his skin and the wet towels above and below the operation site, where it will not get in the way.
Swab the trolley with the solution, or put the instruments on a solution-soaked towel. Keep two bowls near the operating table, one containing water and the other antiseptic solution. When instruments have been used, wash them in water and keep them in the solution until you use them again. Shake off the excess solution before you use them.
Handle the patient's tissues as little as you can, and try to keep the solution out of his wound as much as possible. Don't let it get into his body cavities.
If his wound is well sutured and is not expected to discharge, leave it open to the air. This is better than covering it with a questionably sterile dressing.
AFTER OPERATING rinse everything free of blood. Rinse the instruments, and put them away. If possible, carry nothing over to the next operation.
Antibiotics in surgery
Antibiotics have two uses in surgery: (1) To treat established infections. (2) In certain circumstances only, and when used in a very particular way, to prevent postoperative infection. They have deliberately been placed last in this chapter, because they are less important than: (1) Careful aseptic theatre routines. (2) A thorough wound toilet (54.1). (3) Delayed primary closure (54.4). (4) Making sure there are no foreign bodies, dead tissue, excessive blood clots, or faeces in the wound. In preventing sepsis, antibiotics give you no licence to neglect the classical rules of good surgery, especially if the patient is diabetic, very old, or very ill, and so less able to overcome any bacteria that may get inside him. So: (1) Handle the tissues gently. (2) Don't leave large pieces of dead tissue in the wound, such as huge, massively ligated pedicles. (3) Where necessary, divert faeces by temporary colostomy.
That said, how can you use antibiotics to the best advantage, when your laboratory staff cannot culture bacteria, or at least not reliably? If they can, do encourage them to examine blood cultures, which are not difficult technically, and, when these are positive, to isolate the organism responsible for septicaemia in pure culture.
If you are fortunate, you will be able to plan a logical antibiotic policy for your district, and keep some antibiotics for hospital use only, in the hope that the arrival of antibiotic-resistant strains from elsewhere in the world will be delayed as long as possible. In such an ideal situation you might decide, for example, that the clinics should use only penicillin and tetracycline, with perhaps a little ampicillin or trimethoprim, and keep streptomycin for tuberculosis only. This will enable you to use chloramphenicol with metronidazole as your main surgical antibiotics, especially when the gut and the genital tract are involved. For other occasions you can use gentamicin (expensive), or a cephalosporin, or a combination of penicillin and streptomycin.
Unfortunately, you are more likely to work in a situation of antibiotic chaos, in which any antibiotic is obtainable over the counter without prescription, and where multiply resistant strains, particularly those resistant to chloramphenicol, are common.
The advice given in later chapters assumes that you are working in an area where chloramphenicol is not freely available in the community, and where organisms resistant to it are uncommon. If they are common, the advice we give may no longer hold, and you had probably better use gentamicin or cephradine.
Particular antibiotics
Some antibiotics are particularly important in district hospital surgery, either because they are life-saving, or because they are good value for money.
Benzyl penicillin is cheap and safe. For organisms that might possibly be sensitive, it is the antibiotic of choice. There is little point in giving very high doses. If penicillin fails to cure a patient, this will probably be because the [gb]- lactamase of penicillin resistant bacteria is destroying it, not because you are not giving enough. In an adult a megaunit six- hourly is the standard dose for a severe infection, such as spreading hand sepsis, or cellulitis round an infected wound. However, if drugs are scarce, one megaunit given to four people is likely to do more good than four megaunits given to one person. In infants, and in patients with cardiac or renal disease, the sodium or potassium in the penicillin can cause undesirable side effects, so be aware of this.
Metronidazole is effective against anaerobes, and as these are often the most important invaders, it has been a major advance. It is bactericidal to most of them, particularly Bacterioides fragilis, and is the drug of choice in the treatment of non-clostridial anaerobic infections and amoebiasis. Resistance to it is unknown, and it has few side effects. It has been expensive, but it is now much cheaper. Give it, blindly if necessary, to all patients who are severely ill with an infection that might be caused by anaerobes, and particularly to patients with intra-abdominal sepsis. Intravenous metronidazole is expensive, but you can achieve adequate blood levels by giving it as suppositories, or as oral tablets rectally. Like this, it is only a tenth the price. Intravenous metronidazole with an aminoglycoside, such as gentamicin, avoids the risk of pseudomembranous colitis (rare). The expensive alternatives, lincomycin and clindamycin, both have this danger. Metronidazole is one of the drugs that no surgeon should be without.
Chloramphenicol is almost outmoded in the industrial world, where expense is less of a constraint. But it is cheap, and has a broad spectrum of activity against aerobic Gram- negative bacilli and Gram-positive cocci. Also, if you don't have metronidazole for anaerobic infections, chloramphenicol is next best. It has good in vitro activity against anaerobes from most parts of the world. It also enters the eye (24.3). Its life-saving properties outweigh the small risk of aplastic anaemia. Chloramphenicol with metronidazole is an excellent combination for established or expected peritonitis (6.2).
Cephalosporins (cephradine). If chloramphenicol is freely available in your community, so that it is much used outside hospital, resistant organisms will be common. If so, instead of using chloramphenicol, use whichever cephalosporin you can get most cheaply, such as cephradine. This is active by mouth, but you may need to give it intravenously. Use cephradine and metronidazole as a substitute for chloramphenicol and metronidazole. For infections with intestinal organisms cephradine and metronidazole is a substitute for gentamicin and metronidazole. Remember that 10% of penicillin-sensitive patients are also sensitive to cephalosporins.
Gentamicin is a very valuable broad spectrum aminoglycoside antibiotic for organisms which are likely to be resistant to other antibiotics. It has been expensive, but is now out of patent and is much cheaper. At the time of writing (June 1988) ECHO cost a day's treatment at $0.13 compared with $2.3 for cephradine. For the blind' treatment of a serious infection, especially one due to intestinal bacteria, give gentamicin with metronidazole, perhaps with penicillin.
Trimethoprim alone is preferable to cotrimoxazole (Bactrim', Septrin'), which is a combination of trimethoprim and sulphamethoxazole. The latter is rather toxic and not very effective. If you don't have trimethoprim, use cotrimoxazole.
Tetracycline. Oxytetracycline (Terramycin') is likely to be the cheapest tetracycline.
Methods for using antibiotics
Antibiotics for treating established infection call for little comment, and are described in many places in these manuals. Antibiotics to prevent infection need to be used wisely, in ways in which their benefits outweigh their risks. An operation site which has no bacteria in it to start with can become contaminated with bacteria from:
(1) Outside the patient, in which case they will probably be staphylococci. Preventing such infection is the purpose of the ordinary aseptic routines, and prophylactic antibiotics are no substitute for it. Most surgical patients do not need antibiotic cover for sepsis of this kind. The only absolute indication for it is to cover the implantation of prostheses, which you are unlikely to do.
(2) Inside a patient, when you operate on his large gut or his lower urinary tract, or on a woman's genital tract.
When you use antibiotics prophylactically, aim to provide a concentration in the patient's blood that will kill any bacteria introduced into his wound at the time of the operation. If you want to minimize the risk of peritonitis, he will need protection against enterobacteria (mostly Esch. coli), as well as aerobic and anaerobic streptococci. He will also need protection against bacterioides, and clostridia.
The accepted ways to give antibiotics are:
(1) To give them perioperatively, so that high concentrations are reached in a patient's wound at the time of surgery. Give them intravenously with the premedication, and for 24 to 48 hours only afterwards, unless there is some good reason for continuing them. Starting them a day or more before the operation, or continuing them unnecessarily afterwards, promotes the selection of resistant organisms and the risk of side-effects.
(2) To instil them into the peritoneum after the pus from peritonitis has been washed out. Tetracycline is very effective in preventing postoperative sepsis in the peritoneum, and in the wound in the abdominal wall.
There are several unacceptable methods: (1) Don't put topical antibiotics into a patient's wound. (2) Don't give them by mouth in the hope of sterilizing his large gut'[md]systemic antibiotics are probably at least as effective, and safer.
As to the antibiotics to use, you will see from the list of indications below that, if chloramphenicol is not much used in the community, chloramphenicol with metronidazole is likely to be the most cost-effective combination. Otherwise, give cephradine (or some other cephalosporin) with metronidazole. These are certainly much better than one commonly used alternative, which is penicillin and streptomycin.
Try to separate prophylaxis from treatment. For prophylaxis give chloramphenicol, or a cephalosporin with metronidazole. For treatment give gentamicin and metronidazole.
Barker EM, Rectal adminstration of metronidazole in severely ill patients', British Medical Journal 1983;287:311[nd]313.[-3] Keighley MRB, Perioperative antibiotics', British Medical Journal, 1983;286:1844[nd]1846. THE DOSE AND THE TIMING ARE CRITICAL GET ADEQUATE LEVELS AT THE TIME OF SURGERY
ANTIBIOTICS PERIOPERATIVE PROHPHYLAXIS INDICATIONS. (1) Peritonitis. (2) Any operation which is likely to contaminate a patient's peritoneal cavity, especially large bowel surgery. Use a combination of metronidazole with either an aminoglycoside (such as gentamicin), or a cephalosporin, or, to save cost, chloramphenicol. (3) An operation on his urinary tract when his urine is already contaminated, including bouginage, cystoscopy, and Freyer's prostatectomy. Use an aminoglycoside (gentamicin), a cephalosporin (cephradine), or chloramphenicol. (4) Hysterectomy: as (2). (4) Emergency Caesarean section.
Balance cost and benefit. The instillation of tetracycline solution into the peritoneum (see below) may be comparatively expensive; but if it saves another operation for a residual abscess it is cheap.
CAUTION ! Gentamicin and other aminoglycosides may seriously prolong the action of long-acting (non-depolarizing) relaxants (A 14.3), and may prevent the establishment of spontaneous ventilation. Avoid them unless your anaesthetist is experienced.
CONTRAINDICATIONS. Antibiotics are not needed for: (1) Already well localized infections. (2) Hernias, ovarian cysts, etc.
Disputed indications include elective Caesarean section and appendicectomy.
DOSE. Give two intravenous doses of two suitable antibiotics, one of which is active against aerobic organisms, and the other against anaerobes. Give the first dose intravenously with the premedication. You are only giving two doses, so it is safe to use large ones. Give the second dose 6 hours later. If you are using a tourniquet, time the injection to give the maximum concentration about the time that you release it, so that the clot which forms in the wound will be heavily loaded with drug.
For the aerobic organisms, give: chloramphenicol, or gentamicin, or a cephalosporin, or trimethoprim. Gentamicin is the most potent, but also the most expensive.
For anaerobes, particularly bacterioides give metronidazole. Chloramphenicol is also active, but is less effective.
PARTICULAR ANTIBIOTICS BENZYLPENICILLIN (penicillin G) can be given by several routes. 600 mg is one megaunit (M).
Intramuscularly. Adults, 300 to 600 mg 2 to 4 times in 24 hours. Child up to 12 years 10-20 mg/kg/24 hours. Neonate 30 mg/kg/24 hours.
By intravenous infusion. Adults, up to 24 g in 24 hours. Give it intermittently into a drip. Or give it into an intravenous drip or through a Gordh needle or disposable cannula (Venflon'), flushed through with 1000 units of heparin.
By intrathecal injection. Adults, 6 to 12 mg in 24 hours.
METRONIDAZOLE, for anaerobic infections Adults, by mouth, 400 mg 8-hourly. By rectum 1 g 8-hourly for 3 days, then 1 g every 12 hours. By intravenous infusion, 500 mg 8-hourly for up to 7 days. Children, any route, give 7.5 mg/kg 8-hourly.
If a patient is seriously ill, give 500 mg (100 ml of 0.5% solution) intravenously as a loading dose over 45 minutes. Preferably give another similar dose 8 hours later. At the same time give a 1 g suppository 8-hourly. For perioperative prophylaxis (as for an emergency Caesarean section or large gut resection) continue for 24 to 48 hours. For peritonitis continue for 5 days.
If you don't have adequate supplies of intravenous metronidazole, you may be able to give it orally, or by suppository, or as an ordinary tablet rectally (1 g 6 to 8- hourly), before and after the operation. Adequate blood levels are not reached for 8 hours after giving a suppository, so start with one, or, better, two intravenous loading doses, and continue with suppositories. Or if you have no intravenous solution, use suppositories only, and start them earlier. It has been suggested that presently accepted doses may be high, and that a 500 mg suppository 12-hourly may be adequate.
CHLORAMPHENICOL. There are several regimes.
Perioperatively. Adults, give 1 g by bolus intravenous injection.
Intravenously. Adults, give an adult 1 g 6-hourly, or 50 mg/kg/24 hours. Child 50 to 100 mg/kg 24 hours in divided doses. Decrease the high dose as soon as clinically indicated. Infant: 50 mg/kg/24 hours in divided doses. Neonate under 2 weeks: 25 mg/kg/24 hours in divided doses. Premature baby: 12.5 to 25 mg/kg/24 hours. In neonates it may cause the grey syndrome', but probably not with lower doses.
By mouth. Adults, give 500 mg 6-hourly or 50 mg/kg/24 hours in divided doses for 5 days. Then give 250 mg 4 to 6-hourly for up to 10 days. For children give 25-100 mg/kg/24 hours in divided doses.
In grave emergencies high doses may be justified. Section 31.8 describes a short high dose chloramphenicol regimen for treating typhoid (1 or 2 g 4-hourly for 5 days followed by 250 mg 6-hourly for 14 days). One of the dangers with exceptionally high dosage schemes is that you may come to think of them as normal, and so increase your antibiotic bill unduely.
CAUTION ! (1) Avoid long courses of chloramphenicol. It is among these patients that most cases of aplastic anaemia and leucopenia occur. Their reported incidence in the industrial world is 1:5,000 to 1:10,000 cases. Their incidence is probably lower in non-Caucasians. (2) Avoid intramuscular chloramphenicol; it is poorly absorbed.
CEPHRADINE (other cephalosporins have different doses).
By mouth, 250 to 500 mg 6-hourly. Or, 0.5 to 1.0 g 12-hourly. In children 25 to 50 mg/kg in 24 hours in divided doses.
By intramuscular or intravenous injection, 0.5 to 1 g every 6 hours, increased to 8 g in 24 hours in severe infections. Children 50 to 100 mg in 24 hours in 4 divided doses.
GENTAMICIN. By intramuscular injection or slow intravenous injection or infusion, 2 to 5 mg/kg/24 hours, in divided doses every 8 hours. Children up to 2 weeks give 3 mg/kg every 12 hours. 2 weeks to 12 years give 2 mg/kg every 8 hours.
By intrathecal injection 1 mg in 24 hours, with 2 to 4 mg/kg by intramuscular injection in divided doses every 8 hours.
CAUTION ! In renal impairment the interval between successive doses should be increased.
TRIMETHOPRIM. Adults: by mouth in an acute infection 200 mg 12 hourly. Chronic infections and prophylaxis 100 mg at night. Children: twice daily 2 to 5 months 25 mg, 6 months to 5 years 50 mg, 6 to 12 years 100 mg.
By slow intravenous injection or infusion, 150 to 200 mg 12-hourly. Child under 12 years 6 to 9 mg/kg/24 hours in 3 divided doses.
TETRACYCLINE. Oxytetracycline is likely to be the cheapest preparation. For peritonitis, or contamination of the peritoneal cavity with faeces, wash out the pus or faeces with saline until the fluid comes away clear. Then instil 1 g of oxytetracycline in 1000 ml of saline. Close the abdomen without drains.
THE TREATMENT [s7]OF SURGICAL SEPSIS See also particular conditions: peritonitis 6.2, osteomyelitis 7.4, septic arthritis 7.16 etc.
CAUTION ! In any form of sepsis, antibiotics are not a substitute for surgery when this is necessary.
SPREADING PRESUMPTIVE GRAM-POSITIVE SEPSIS when you don't know the sensitivities[md]give chloramphenicol, cephradine, cloxacillin or methicillin.
SERIOUS PRESUMPTIVE ANAEROBIC SEPSIS, especially intra- abdominal sepsis. Give metronidazole, intravenously or as suppositories with a loading dose intravenously (if available). There may be aerobes also, so give chloramphenicol or gentamicin or cephradine in addition. Continue for not more than 5 days.
PELVIC SEPSIS. Chloramphenicol with metronidazole, or cephradine with metronidazole, or, much less satisfactorily, penicillin with streptomycin.
SEVERE SOFT TISSUE WOUNDS. If there is risk of gas gangrene give benzyl penicillin (or erythromycin if the patient is sensitive to penicillin). And give metronidazole.
INFECTED ABDOMINAL WOUNDS. (1) Chloramphenicol or cephradine as above. Or, (2) a megaunit of benzyl penicillin 8- hourly, and intravenous ampicillin 1 g initially, followed by 0.5 g 8-hourly. AND, give metronidazole 500 mg intravenously initially followed by 1 g 8-hourly by rectum for up to 5 days.
BLIND THERAPY'. For the severely ill patient presumed to have an infection when the nature and sensitivities of the organism are unknown: give chloramphenicol or cephradine or gentamicin, all with metronidazole. Consider giving benzyl penicillin or ampicillin also if the infection is generalized.
ONLY A FEW HIGH RISK PATIENTS NEED PERIOPERATIVE PROPHYLACTIC ANTIBIOTICS
When prevention fails - wound infection
If a patient's wound discharges pus, the aseptic routines described earlier in this chapter have broken down. Although this is not the only cause of a wound infection, it is the most unnecessary one.
Keep a record of your wound infections. They are most likely to occur if: (1) You are operating for some infective condition, such as an acute appendix. (2) The operation is long and difficult. (3) You leave dead tissues, foreign bodies, dirt, or clot, or an excessive number of sutures in the wound. (4) You create dead tissue by operating clumsily. (5) You close a wound by immediate primary closure, when delayed primary closure would been have been wiser (54.4).
If more than about 5% of your clean cases become infected, something has gone wrong. Prophylactic antibiotics are not the answer! The chances are that the aseptic disciplines in Section 2.2 are not being followed, or you are making the errors 3, 4, and 5 above.
SURGICAL SEPSIS. Here are some of the errors that can be made and the lessons to be learnt from them, mostly from the pre- antibiotic days.
(1) A theatre had extractor fans installed, but the only inlets for fresh air were under the doors, so that dust from the corridor was drawn into the theatre continually. Only when three patients had died of tetanus was the flow of the fans reversed. LESSON Keep dust out of the theatre.
(2) In the days before antibiotics a London teaching hospital had two minor theatres in which many septic operations were done. On two mornings a week the same equipment was used for a list of circumcisions. One circumcised child acquired erysipelas which spread from his umbilicus to his toes and killed him. LESSON Where possible don't do clean cases in a theatre which normally does septic ones.
(3) An eminent professor resected a carcinoma of the pelvic colon and did an end-to-end anastomosis, without doing a preliminary colostomy. The patient's gut obstructed, and when his abdomen was explored there was a huge abscess round a leaking anastomosis. Peritonitis killed him. LESSON If there are surgical procedures which will minimise the risk of infection, use them.
(4) Hamilton Bailey, subsequently a distinguished surgeon, but then a registrar, was deputizing for his chief. Having done a cold list' which began at 1.30 p.m. he insisted on continuing with a non-stop flood of emergencies which continued rolling in all the evening. At 3 a.m. the following morning, dead on his feet', he pricked himself when operating on a patient with streptococcal peritonitis. Bailey insisted that his finger be amputated, and survived. The patient died. LESSON Accidents, including those which increase the risk of sepsis, are particularly likely if you are overtired. Amputation for this reason should never be necessary, now that antibiotics are available. Stirling HL, The aetiology, prevention, and treatment of surgical sepsis', Tropical Doctor 1979;2:131[nd]134.
WOUND INFECTIONS For the care of particular wounds, see the appropriate sections, for example, laparotomy wounds (9.12), rectal wounds (66.12), joint wounds (69.8).
THE PREVENTION OF WOUND INFECTIONS AUTOCLAVING. (1) Check that your autoclave does reach 1 kg/cm['2] (2.4), that the air is being discharged, and that the holding time is being maintained. (2) Check that the drums are not being overpacked, that they are labelled after autoclaving, and that the label includes the date.
THEATRE DISCIPLINE. Check that you and ALL your staff are following all the aseptic disciplines in Section 2.3 carefully. If you set the example, your staff will follow them.
Check that: (1) the theatre table and especially the macintosh cover on its mattress, are being properly cleaned, (2) there is no infected member of staff.
SURGICAL TECHNIQUE. Examine yourself. Are you committing errors 3, 4, or 5 above?
THE TREATMENT OF WOUND INFECTIONS Sedate the patient with morphine (or pethidine) and diazepam. In infected sutured wounds the pus usually tracks the whole length of the subcutaneous tissues. So remove all sutures and convert the wound into a gutter. Either allow it to granulate or close it by secondary suture. If possible, send a swab for culture.
Establish free drainage, especially in the depths of the wound, keep it open so that it can heal from the bottom, and let it drain into dressings.
If a wound fails to heal, think of HIV (Chapter 28a).
