Surgical Techniques

SURGICAL TECHNIQUE
David M.A. Francis > Chapter 4 > Tjandra JJ, Textbook of Surgery 3rd Edition. Blackwell Publishing. 2006

INTRODUCTION

This chapter reviews techniques used in surgical prac­tice and invasive procedures.

THE OPERATING ROOM

The operating room is a dedicated area for surgical pro­cedures and must be conducive to performing surgery to the highest standards of safety for patients and staff. The principal purpose of such a dedicated area is to reduce the risk of infection of patients. The operating room must be large enough for complex procedures to be undertaken, for storage of appropriate equip­ment, movement of staff, as well as the maintenance of a sterile area around the operative field. By chang­ing the operating room air 20-25 times each hour at positive pressure relative to outside the room, low con­centrations of airborne bacteria and particulate matter can be maintained. The number of people in the room and their movement should be minimised. Ambience should be calm and professional, and the air temper­ature such that inadvertent patient hypothermia does not occur. The operative field must be well illuminated by direct bright light, and surgeons sometimes wear a head light for procedures in body cavities which can­not be illuminated easily by standard operating room lights.

The surgeon's assistant has the important role of as­sisting and supporting the surgeon in the smooth con­duct of operations. It is important to concentrate on the task at hand, to carry out the surgeon's instructions with speed and accuracy, to have a sense of anticipa­tion, and to notify the surgeon of any potential hazard during the operation.

A face mask which covers the nose and mouth prevents droplet spread of bacteria, is worn for any

invasive procedure and is changed after each case. Eye protection in the form of plain plastic glasses or a visor attached to the face mask must be worn to protect against droplet spray of infected body fluids. Gloves are worn if there is a possibility of coming into contact with patients' body fluids. Clean theatre attire, ded­icated theatre shoes, and a disposable hair cover are worn while in the operating suite.

ASEPTIC TECHNIQUE

Aseptic techniques are clinical practices which aim to prevent infection occuring in the patient as a result of the surgical procedure by:

· Preparation and cleaning the patient's skin with an­tiseptic fluid before it is cut or punctured.

· Use of sterilised instruments, equipment or surgical materials which might come into contact with the operative field and surgical wound.

Personnel involved directly in the operative procedure (surgeon, surgical assistant and 'scrub' nurse) wash their hands and forearms with antiseptic soap for 5 minutes before the first operation of the day and for 3 minutes before each subsequent case to reduce skin flora. Hands are dried with sterile towels, and a moisture-impermeable sterile gown is worn. One or two pairs of sterile gloves prevent transfer of bacteria from the surgeon's hands to the patient and also pro­tect the surgeon from infected blood and body fluids from the patient.

The patient should shower or bathe with an anti­septic soap before going to the operating room. After induction of anaesthesia, hair is removed from the op­erative site by shaving with a razor or electric clippers. The skin is cleansed with an antiseptic solution starting at the site where the incision will be made and working away from the area, so that approximately 10-20 cm of skin around the incision site is prepared. The patient is covered with sterile linen or impermeable drapes,leaving exposed only the cleansed area around the in­cision site, which may be covered by a sterile adhesive plastic drape.

Surgical antiseptics

The commonest source of bacterial contamination in the operating room is from the patient. Therefore, top­ical antiseptic agents are used to reduce the number of skin organisms prior to any skin incision or puncture, and include:

· Aqueous chlorhexidine (0.5%) is used to disinfect mucous membranes and parts of the body adjacent to structures which would be adversely affected by more stringent antiseptics (e.g. the skin around the eyes). Aqueous chlorhexidine is bactericidal and has low tissue toxicity.

· Cetrimide (2%) is bactericidal.

· Iodine-based antiseptics (e.g. povidone iodine (10%) [Betadine], alcoholic iodine solution) destroy a wide range of bacteria, especially staphylococci, by iodis-ation of microbial proteins.

· Alcohol-based (70%) antiseptics kill bacteria by evaporation.

Sterility

Anything that comes into contact with the surgical wound must be sterile. The method of sterilisation de­pends on the item being sterilised (Box 4.1).

Universal precautions

The risk of transmission of infectious agents from pa­tients to staff (and vice versa) is reduced by prac­tising universal precautions. Thus, it is assumed that all patients harbour potentially dangerous pathogens (e.g. hepatitis C, HIV) no matter how innocuous they appear, because carrier status cannot definitely be excluded without repeated, expensive and time con­suming investigations. The principle of universal pre­cautions is to establish a physical barrier between the patient and the carer to prevent direct contact with any potentially infected body fluid or tissue in either direction (Box 4.2).

Hazards
In addition to infection, there are many potential sources of hazard in the operating environment.Hazards, other than those intrinsic to the anaesthetic and surgical operation, are organisational, or related to operating room equipment or the transfer and posi­tioning of the patient on the operating table.

Organisational hazards
Organisational hazards should be entirely preventable. A full history and examination of the patient must be made before surgery, including the past medical history, drug history and allergies, so that elementary errors are not made (e.g. unwittingly operating on a patient with a pacemaker or who is anticoagulated, or prescribing a drug to which the patient is allergic). Before surgery commences, the reason for and nature of the operation, together with its potential common and serious com­plications, and the reasonable expectations from the procedure, are discussed with the patient and family who are free to ask any questions. A consent or request for treatment form, which states the nature of the op­eration and the side on which the operation is to be performed if the operation is a unilateral procedure, is signed by the patient and the surgeon or deputy.

Once in the operating suite, a check is made that the patient is the correct one for that procedure, that the correct side or limb is identified and marked with an indelible pen, and that the lesion or lump is similarly marked to ensure that there is no confusion after the patient has been anaesthetised. All relevant case notes, investigation results and X-rays must be available in the operating room.

Equipment

Diathermy is used universally in surgical practice. High frequency alternating current passes from a

small point of contact (active electrode) through the patient to a large contact site (indifferent electrode or diathermy plate) to produce localised heat which coagulates protein. Diathermy produces either (a) co­agulation – haemostasis with a small amount of ad­jacent tissue damage, (b) cutting – tissue cutting with minimal tissue damage, or (c) fulgaration – haemostat-sis with considerable tissue necrosis. Potential hazards include electrocution, inadvertent burn to the patient at a remote site and to the surgeon, fire associated with pooled alcohol-based antiseptics, explosion of flammable anaesthetic gases, and interference with the function of cardiac pacemakers.

A variety of lasers with different wavelengths and ef­fects on cells and tissues are used in surgical practice for highly accurate tissue destruction (e.g. mucosal surgery, CNS tumours, dermatological lesions, aerodigestive tumours), coagulating blood vessels (e.g. gastroin­testinal tract, retinal photocoagulation), and for photo-activation of intra-tumour haematoporphyrin for malignant tumour destruction (photodynamic therapy). Hazards include eye damage, explosion of anaesthetic gases, and shattering and destruction of other equipment.

Limb torniquets are used to provide a blood-less field in which to operate. The limb is elevated and exsan­guinated by a rubber bandage or compressive sleeve, and the proximal torniquet inflated to 50 mm Hg (up­per limb) or 100 mm Hg (lower limb) above systolic blood pressure. A torniquet should not be kept inflated for more than 60–90 minutes. Hazards include arterial thrombosis, distal ischaemia, nerve compression and skin traction.

Positioning of the patient

The patient is positioned on the operating table in such a way that the procedure is facilitated and the airway can be protected. Pressure points are padded, and limbs are positioned so that peripheral nerves, major blood vessels, joints and ligaments are not stretched or com­pressed. The anaesthetised patient must be in a sta­ble position on the operating table and may need to be strapped on with broad adhesive tape. There must be no contact between the skin and any metallic sur­face because of the risk of diathermy burn and pressure necrosis. Sections of the operating table can be angled so that the patient is optimally positioned for the par­ticular procedure (e.g. flexed while lying supine or on one side, head-down, head-up).

ENDOSCOPY

Endoscopy is performed by inserting a fibre-optic tele­scope containing a light source and instrument chan­nels into the gastrointestinal, respiratory and urinary tracts. The operator undertakes the procedure by ma­nipulating the endoscope while viewing a video screen or looking down the eye piece of the instrument.

Gastrointestinal endoscopy

Endoscopy of the gastrointestinal tract allows the endoscopist to view the lumen of the oesophagus, stom­ach and proximal half of the duodenum (oesophago-gastroduodenoscopy), colon (colonoscopy), and rectum and distal sigmod colon (sigmoidoscopy), and distal rectum and anal canal (proctoscopy). It is usually performed under sedation. Intestinal endoscopy can also be performed at laparotomy (enteroscopy) by making a small incision in the intestine and the surgeon passes the endoscope along the intestinal lumen. Procedures, such as dilatation of strictures, biospy and diathermy ablation of polyps, injection of adrenaline around bleeding gastric and duodenal ulcers, cholangio-pancreatography, removal of com­mon bile duct calculi, injection of haemorrhoids, and tumour phototherapy can be performed using fibre-optic endoscopes.

Bronchoscopy

The upper airway, trachea and proximal bronchi can be inspected by bronchoscopy, which may be performed under local or general anaesthesia. Bronchoscopy is used for diagnosis (e.g. inspection and biopsy of lung tumours) or therapy (e.g. removal of foreign bodies, as­piration of secretions). Anaesthetists ocassionally use the fibre-optic bronchoscope to facilitate difficult en-dotracheal intubation.

Urological endoscopy

The urethra (urethroscopy), bladder (cystoscopy), and ureters (ureteroscopy) can be inspected for diagnostic purposes. Extensive therapeutic procedures (e.g. resec­tion of the prostate, diathermy and excision of bladder tumours, extraction of calculi) can be performed safely with far less morbidity than the equivalent open pro­cedures.

ENDOSCOPIC SURGERY

Endoscopic surgery is performed by inserting a micro­chip video camera with a light source and specially crafted long-handled surgical instruments into a body cavity by way of small incisions. The surgeon under­takes the procedure by manipulating the instruments while viewing a video screen.

The advantages of endoscopic or 'closed' surgery are reduced post-operative pain and analgesic require­ments, earlier discharge from hospital, and earlier return to normal function. However, many surgical procedures either cannot be undertaken endoscopically because of their very nature, or cannot be completed endoscopically because of difficulty or patient safety, in which case the operation is converted to an 'open' procedure. Some procedures use endoscopic techniques to assist with the procedure and an incision is made to either complete the operation or deliver the re­sected specimen (e.g. bowel resection, nephrectomy, splenectomy). The range of endoscopically performed operations in many surgical specialties has increased enormously over the last 10-15 years.

Abdominal surgery

Laparoscopy refers to the technique of insufflating the peritoneal cavity with gas, inserting a camera through a 10-15-mm sub-umbilical incision and inspecting the abdominal contents. Usually, three additional ports are inserted through 5-10-mm incisions in the abdomi­nal wall and instruments (e.g. scissors, grasping de­vices, retractors, staplers, needle holders) are intro­duced and manipulated by the surgeon to perform the operation. Procedures such as cholecystectomy, gas­tric fundoplication, hiatus hernia repair, division of ad­hesions, appendicectomy, splenectomy, adrenalectomy, nephrectomy, oophorectomy, tubal ligation, and her­nia repair can be undertaken laparoscopically with less morbidity than if undertaken as an open or conven­tional operation. Endoscopic surgery has allowed some procedures to be undertaken as day cases, whereas the same procedure performed as an open operation would require an inpatient stay of several days (e.g. cholecys­tectomy, hernia repair).

Thoracic surgery

Thorascopy involves inserting a camera with a light source and instruments into the thoracic cavity. The technique is used diagnostically and therapeutically for procedures such as drainage of the thoracic cav­ity (haemothorax, pleural effusion and empyema), lung biopsy, pleurodesis, and excision of lung bullae. The mediastinum can be inspected and mediastinal lymph nodes can be biopsied by mediastinoscopy, which may prevent the need for an exploratory thoracotomy.

Orthopaedic surgery

Large joints (e.g. knee, hip, ankle, shoulder, wrist) can be inspected by arthroscopy. Therapeutic procedures include removal of bone chips, cartilage excision and removal, and ligament repair. Arthroscopic surgery has been enormously beneficial for orthopaedic patients and has allowed far more rapid return to function.

Open surgery

Open surgery is the traditional or conventional method of operating. In general terms, open surgery involves making a surgical wound, dissecting tissues to gain access to and mobility of the structure or organ of in­terest, completing the therapeutic procedure, ensuring haemostasis is complete, and then closing the wound with sutures. Open surgey is performed more with the hands and direct touch than endoscopic procedures, and fingers may be used for 'blunt' dissection. The sur­gical wound accounts for much of the morbidity of open surgery, particularly the cutting of muscle. The range of open operations is extremely wide, as evi­denced by the procedures described throughout this book.

SURGICAL METHOD

Surgical operations are performed by well worked out, standardised steps which progress in logical sequence. An operative plan is worked out by the surgeon for every operation.

Surgical instruments

There are literally thousands of surgical instruments, some simple and others extremely complex, but each designed for a specific function. The surgical incison is made with a scalpel which consists of a re-usable handle and a disposable blade. Scissors are used to cut other tissues and sutures, and for blunt dissection with the blades closed. Diathermy is used for haemostasis and to cut through tissue layers beneath the skin. Tissues are held with dissecting or tissue grasping for­ceps rather than the fingers. Hand-held forceps either have teeth which tend to dig into and damage tissues, or are non-toothed with poorer grasping ability. Nee­dle holders are used to grasp needles for suturing and eliminate the need for hand-held needles, and are there­fore safer. They have a ratchet so that the needle can be contained securely in the holder while not in the sur­geon's hand. Retractors allow the surgeon to operate in an adequately exposed field. Self-retaining retractors keep the wound edges apart without the aid of an as­sistant. Retractors held by the assistant provide tissue retraction in awkward parts of the wound and in situ­ations where retraction of specific tissues is required so that intricate parts of the operation can be performed. A sucker is used to aspirate blood and body fluids from the operative field and to remove smoke created by the diathermy. There are many instruments designed specifically for surgical specialties and procedures.

Incisions

Surgical incisions are made so that:

· The operation can be undertaken with adequate ex­posure of the area or structure of interest.

· The procedure can be performed and completed safely and expeditiously.

· The wound heals satisfactorily with a cosmetically acceptable scar.

Thus, incisions are to be of adequate but not excessive length and, if possible, placed in skin creases, partic­ularly when operating on exposed areas of the body such as the face, neck and breast. Parallel skin inci­sions (tram tracking) and V- or T-shaped incisions are avoided because of ischaemia of intervening tissue and pointed flaps.

Tissue dissection

Ideally, surgical dissection should be performed along tissue planes which tend to be relatively avascular. The aim is to isolate (mobilise) the structure(s) of interest from surrounding connective tissue and other struc­tures with the least amount of trauma and bleeding. Tissues should be handled with great care and respect and as little as possible. Dissection is undertaken by using a scalpel or scissor (sharp dissection), a finger, closed scissor, gauze pledget, or scalpel handle (blunt dissection), or the diathermy. Gentle counter traction on tissues by the assistant facilitates the dissection.

Haemostasis

Surgical haemostasis refers to stopping bleeding which occurs with transection of blood vessels. The major­ity of cases of operative and post-operative bleeding are due to inadequate surgical haemostasis rather than disorders of clotting and coagulation. Haemostasis is essential in order to prevent blood loss during surgery and haematoma formation post-operatively. Methods of surgical haemostasis include:

· Application of a haemostatic clamp to a blood ves­sel and then ligation with a surgical ligature .

· Suture ligation of a vessel - under-running a bleeding vessel with a figure-of-8 suture which is tied firmly.

· Diathermy coagulation.

· Localised pressure for several minutes to allow coag­ulation to occur naturally.

· Application of surgical materials (e.g. oxidised cellu­lose, Surgicell) which promote coagulation.

· Application of topical agents to promote vasocon-striction (e.g. adrenaline) or coagulation (e.g. throm-bin).

· Packing of a bleeding cavity with gauze packs as a temporary measure until definitive haemostasis can be achieved.

Sutures

Sutures have been used to close surgical wounds for thousands of years, and initially were made from hu­man or animal hair, animal sinews, and plant material. Today, a wide variety of material is available for sutur­ing and ligating tissues (Box 4.3). Sutures are selected for use according to the re­quired function. For example, arteries are sutured together with non-absorbable polypropylene or poly-tetrafluoroethylene (PTFE) sutures which are non-thrombogenic, cause virtually no tissue reaction, and maintain their instrinsic strength indefinitely so that the anastomotic scar (which is under constant arte­rial pressure) does not stretch and become aneurys-mal. Skin wounds, for example, are sutured with ei­ther non-absorbable sutures, which are removed after several days, or absorbable su­tures hidden within the skin (subcuticular sutures) and which are not removed surgically but are absorbed after several weeks.

Sutures are available in diameters ranging from 0.02-0.50 mm. The minimum calibre of suture should be used, compatible with its function. Non-absorbable sutures are avoided for suturing the luminal aspects of the gastrointestinal and urinary tracts because sub­stances within the contained fluids (e.g. bile, urine) may precipitate on persisting sutures and produce calculi.

The requirements of suture material are:

· Tensile strength - the suture must be strong enough to hold tissues in apposition for as long as required.

· Durability - the suture must remain until either heal­ing is advanced or indefinitely if the healed tissue is under constant pressure.

· Reactivity - tissue reaction (i.e. an inflammatory re­sponse) allows absorbable sutures to be removed by phagocytosis but results in chronic inflammation if non-absorbable sutures remain in situ.

· Handling characteristics - sutures must be easy to grasp, handle and tie.

· Knot security - sutures must be able to be tied effec­tively so that knots do not come undone or slip. Sutures are classified as:

· Absorbable or non-absorbable. The rate of absorp­tion of absorbable sutures depends on what they are made of and their thickness. Disappearance of the su­ture occurs through inflammatory reaction, hydroly­sis or enzymatic degradation.

· Synthetic or natural material. Sutures of natural (an­imal) origin are being phased out of surgical practice because of the very minimal risk of disease transmis­sion. A wide variety of synthetic suture materials are available.

· Monofilament or multifilament. Monofilament su­tures pass through tissues easily, are generally less reactive, and are more difficult to handle and knot se­curely. Multifilament sutures are braided or twisted thread, and are easier to handle and knot, but are

more likely to harbour micro-organisms within the suture.

Surgical knots

Knots are tied to ensure that ligatures and sutures re­main in place and do not slip or unravel. The ability to tie a secure knot is a fundamental technique in surgery, and patients’ lives literally depend on knot security (e.g. the knot in a ligature used to tie off an artery). Knot security depends on friction between the throws of the ligature material, the number of throws used to tie the knot, the strength of the ligature material, and the tight­ness of the knot. Usually, multiple throws are used to secure the knot (e.g. two reef knots, one on the other).

Suturing

The technique of suturing depends on the tissue and wound being sutured. Sutures may be either continu­ous (e.g. subcuticular skin sutures, abdominal closure, vascular anastomosis), or interrupted (e.g. skin sutures, sternal wires). The function of sutures is to hold the adjacent edges of sutured tissues in apposition and to immobilise them in that position so that wound heal­ing (i.e. neovascularisation, connective tissue ingrowth and collagen formation) is facilitated. It is essential that sutures are not tied so tightly that the tissues encom­passed by them become ischaemic. Skin sutures may be supported by adhesive paper tapes.

Retention sutures (incorrectly referred to as tension sutures) are used toclose abdominal incisions which are thought to be at increased risk of dehiscence, and are inserted to encompass a large amount of fascial tissue and are placed 3–5 cm apart.

Within the last two decades, stainless steel staples have been used to close skin wounds and to perform gastrointestinal anastomoses. Staples are quicker to use than sutures, but are relatively expensive and produce a worse cosmetic result for skin closure than subcuticular absorbable sutures.

Suture removal
Sutures are removed as early as possible to minimise the risk of infection and scarring, so long as tissue healing is sufficently advanced that the wound will not open when the sutures are removed. Sutures are therefore removed at different times, depending on tissue and general patient factors (Box 4.4). For example, sutures are left in situ for a longer time in patients who are immunosuppressed, malnourished, jaundiced, or undergoing chemotherapy; who have re­nal failure, and in tissues judged to be relatively is-chaemic, subject to increased stress and tension, and which have been irradiated.

SURGICAL DRAINS

Drains are used widely in surgical practice to

· Remove blood or serous fluid, which would other­wise accumulate in the operative area (e.g. wound drain).

· Provide a track or line of minimal resistance so that potentially harmful fluids can drain away from a par­ticular site (e.g. drain placed into an intra-abdominal abscess cavity).

Several different methods of drainage may be used de­pending on the required function.

· Open drainage - a drain tube or strip of soft flex­ible latex rubber is placed so secretions or pus can drain along the track of the drain into gauze or other dressing covering the external end of the drain tube (e.g. drain placed in an abscess cavity, drain placed prohylactically near a bowel anastomosis in case of subsequent anastomotic leak).

· Closed drainage - a tube is placed into an area or vis-cus to drain fluid contents into a collecting bag so that there is no contamination of the drained area from outside the system (e.g. chest drain, urinary catheter, cholecystostomy drain).

· Closed suction drain - the drain tube is connected to a bottle at negative atmospheric pressure so that fluid is sucked out of the area (e.g. wound drain, drain under skin flaps).

It is important to note both the amount and the type of fluid which drains. Large volumes of fluid drainage may need to be replaced as intravenous fluids (e.g. duo­denal fistula fluid). Depending on the particular situa­tion, it may be necessary to culture drain fluid or send it for estimation of haemoglobin, creatinine, electrolytes, amylase or protein. A radiological contrast study may be performed along the drain tube, for example to estimate the size of a cavity being drained.

Drain tubes are removed when they are no longer required, for example when there is minimal fluid being drained, or when a cavity being drained has contracted and is small. Drains are removed simply by cutting the suture which anchors them to the skin and withdrawing the tube from the patient.

VENEPUNCTURE

Venepuncture involves removing blood from a superfi­cial vein, usually in the antecubital fossa or dorsum of the hand, by inserting a needle attached to a syringe or collection tube at negative pressure (vacutainer system). A venous torniquet is applied around the arm, which is hung in a dependent position; the patient vigorously opens and closes the hand, and the vein is gently pat­ted to encourage venous dilatation. The skin is cleansed with antiseptic and the needle is inserted through the skin into the dilated vein at an angle of 30-45 degrees. Only the required volume is aspirated, the torniquet is released, the needle is withdrawn, the puncture site is immediately covered with a cotton wool swab, and light pressure is applied for 1-2 minutes. The site is cov­ered with an adhesive dressing. Complications include bruising, haematoma, and rarely, infection and damage to deeper structures. Inadvertent needlestick injury to the venepuncturist is avoided by careful technique.

INTRAVENOUS CANNULATION

Intravenous (i.v.) cannulation is used commonly for ad­ministration of fluids and drugs. Superficial veins on the forearms and dorsum of the hands are used for i.v. can­nulation. Antecubital fossa veins are best avoided for cannulation because the elbow has to be kept extended to avoid kinking of the cannula. Leg veins may have to be used in the absence of useable upper limb veins. Cannulas have a soft outer Teflon sheath attached to a hub, and a central hollow needle attached to a small chamber.

A suitable vein is identified as for venepuncture. Lo­cal anaesthetic cream is applied to the skin overlying the vein or local anaesthetic (1% lignocaine without adrenaline) is injected intradermally next to the vein after cleansing the skin with antiseptic. The cannula (needle and sheath) is inserted through the skin into the vein at an angle of 10-30 degrees and advanced into the vein in the same movement. The needle is re­moved from the sheath and a closed three-way tap or i.v. giving set is joined to the hub of the sheath. The cannula is secured to the skin with adhesive tape.

Intravenous infusion is painful when the infusate is cold or contains irritants (e.g. potassium, calcium, drugs of low or high pH), or if the cannula pierces the vein wall and fluid extravasates subcutaneously. Thrombophlebitis develops at the insertion site after about three days, and i.v. cannulas should be re-sited if infusions are required for longer periods.

CENTRAL VENOUS CATHETERISATION

Percutaneous catheterisation of a central vein is used for

· Short- or long-term venous access when peripheral veins are unsuitable or cannot be used (e.g. prolonged fluid infusion, total parenteral nutrition, ultrafiltra-tion, haemodialysis, plasma exchange, chemother­apy).

· Short-term monitoring of central venous pressure

A central venous catheter (CVC) may be inserted into the internal or external jugular vein or the subclavian vein. Temporary CVCs are made of semi-rigid Teflon, are approximately 25 cm in length and, depending on their function, are between 1 and 4 mm in diameter and have one, two or three lumens. Long-term CVCs are made of barium-impregnated silastic and are quite flexible. They have a Dacron cuff bonded to the part of the catheter which lies subcutaneously and becomes incorporated by fibrous tissue after several weeks so that organisms cannot track along the catheter from the skin into the circulation.

Some long-term single lumen CVCs are available with a small volume chamber attached to the extra-venous end of the catheter (Portacath, Infusaport). The chamber is implanted subcutaneously after the vein is catheterised and can be accessed for chemotherapy or blood sampling by inserting a needle into it through the skin.

CVC insertion is best performed in an operating the­atre, under local or general anaesthesia, and with ul­trasound localisation of the central vein. The patient is placed in a supine, slightly head-down position, and the surface anatomy of the vein is marked. Aseptic tech­nique is essential. A hollow wide-bore needle is inserted into the vein, a guidewire is passed down the needle and the needle is removed. The guidewire position is checked radiologically. A plastic dilator is passed over the guidewire to dilate a track for the catheter and is removed, and the CVC is passed over the guide wire which is removed after the CVC is in place. A chest X-ray is performed to check the final position of the CVC and also to ensure that a pneumo- or haemo-thorax has not occurred due to inadvertent puncture of the pleura or lung. The catheter is sutured to the skin to prevent dislodgement and the exit site is dressed with an adhesive dressing.

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Pre-Operative Management

Pre-operative Management

Iain G. Martin in Textbook of Surgery 3rd Edition, Blackwell Publishing.2006

Introduction

This chapter covers care of the patient from the time the patient is considered for surgery through to im­mediately prior to operation and deals with important generic issues relating to the care of all surgical patients. Whilst individual procedures each have unique aspects to them, a sound working understanding of the com­mon foundation of the issues involved in pre-operative care is critical to good patient outcomes.

Informed consent

Although often thought of in a purely medicolegal way, the process of ensuring that a patient is informed about the procedure that they are about to undergo is a fundamental part of good quality patient care. In­formed consent is far more than the act of placing a signature on a form; that signature in itself is only meaningful if the patient has been through a reason­able process that has left them in a position to make an informed decision.

There has been much written around issues of in­formed consent, and the medico-legal climate has changed substantially in the past decade. It is impor­tant for any doctor to have an understanding of what is currently understood by informed consent.

Although the legal systems in Australia and New Zealand are very different with respect to medical negli­gence, the standards around what constitutes informed consent are very similar.

Until relatively recently, the standard applied to de­ciding whether the patient was given adequate and appropriate information with which to make a deci­sion was the so-called Bolam test, that is practitioners are not negligent if they act in accordance with prac­tice accepted by a reasonable body of medical opinion.

Recent case law from both England and Australia and the standards embedded in the New Zealand's Health and Disability Commissions code of patient rights have seen a move away from the existing position. Although this area is complex, the general opinion is that a doc­tor has a duty to disclose to patients material risks. A risk is said to be material if 'in the circumstances of that particular case, a reasonable person in the pa­tient's position, if warned of the risk would be likely to attach significance to it or the medical practitioner is, or should reasonably be aware that the particular patient, if warned of the risk would attach significance to it'. It is important that this standard relates to what a person in the patient's position would do and not just any reasonable person.

Important factors in considering the kinds of infor­mation to disclose to patients are:

· The nature of the potential risks: more common and more serious risks require disclosure.

· The nature of the proposed procedure: complex inter­ventions require more information as do procedures when the patient has no illness.

· The patient's desire for information: patients who ask questions make known their desire for information and they should be told.

· The temperament and health of the patient: anxious patients and patients with health problems or other relevant circumstances that make a risk more impor­tant for them may need more information.

· The general surrounding circumstances: the informa­tion required for elective procedures might be differ­ent from that required in the emergency department.

What does this mean for a medical practitioner? Firstly, you must have an understanding of the legal frame­work and standards. Secondly, you must be able to document how appropriate information was given to patients - always write it down. On this point, whilst information booklets can be a very useful ad­dition to the process of informed consent they do not remove the need to undertake open discussions with the patient.

Doctors often see the process of obtaining informed consent as difficult and complex, and this view is leant support by changing standards. However, the princi­ples are relatively clear and not only benefit patients but their doctors as well. A fully informed patient is much more likely to adapt to the demands of a surgical inter­vention, and should a complication occur, they almost invariably accept such misfortune far more readily.

Pre-operative assessment

The appropriate assessment of patients prior to surgery to identify coexisting medical problems and to plan peri-operative care is of increasing importance. Mod­ern trends towards the increasing use of day-of-surgery admission even for major procedures have increased the need for careful and systematic peri-operative as­sessment.

The goals of peri-operative assessment are:

• To identify important medical issues in order to

· optimise their treatment.

· inform the patient of the risks associated with surgery.

· ensure care is provided in an appropriate environ­ment.

· To identify important social issues which may have a bearing on the planned procedure and the recovery period.

· To familiarise the patient with the planned procedure and the hospital processes.

Clearly the peri-operative evaluation should include a careful history and physical examination, together with structured questions related to the planned procedure. Simple questions related to exercise tolerance (such as can you climb a flight of stairs without shortness of breath) will often yield as much useful information as complex tests of cardiorespiratory reserve. The clinical evaluation will be coupled with a number of blood and radiological tests to complete the clinical evaluation. There is considerable debate as to the value of many of the routine tests performed, and each hospital will have its own protocol for such evaluations.

On the basis of the outcomes of this consulta­tion a number of risk stratification systems have been proposed; the only one in widespread daily use is the relatively simple ASA (American Society of Anesthesiologists) system.

The pre-operative assessment and work-up will be guided by a combination of the nature of the operation proposed and the overall 'fitness' of the patient. Whilst there are a number of ways of looking at the type of surgery proposed, a simple three-way classification has much to commend it:

· Low risk: poses minimal physiological stress and risk to the patient, rarely requires blood transfusion, in­vasive monitoring or intensive care. Examples of such procedures would be groin hernia repair, cataract surgery, arthroscopy.

· Medium risk: moderate physiological stress (fluid shifts, cardiorespiratory effects) and risk. Usually as­sociated with minimal blood loss. Potential for signif­icant problems must be appreciated. Examples would be laparoscopic cholecystectomy, hysterectomy, hip replacement.

· High risk: significant peri-operative physiological stress. Often requires blood transfusion or infusion of large fluid volumes. Requires invasive monitoring and will often need intensive care. Examples would be aortic surgery, major gastrointestinal resections, thoracic surgery.

A low-risk patient (ASA I or II) will clearly require a far less intensive work-up than a high-risk patient (ASA III or IV) undergoing a high-risk operation.

Areas of specific relevance to peri-operative care are cardiac disease and respiratory disease. It is important that pre-existing cardiorespiratory disease is optimised prior to surgery to minimise the risk of complications. Patients with cardiac disease can be stratified using a number of systems (Goldman or Detsky indices) and this stratification can be used to guide work-up and interventions and provide a guide to prognosis. One of the most important respiratory factors is whether the patient is a smoker; there is now clear evidence that stopping smoking for at least 6 weeks prior to surgery significantly reduces the risk of complications.

Patient safety

Once in hospital, and particularly once under anaes­thetic, patients rely upon the systems and policies of individuals and health care institutions to minimise the risk of inadvertent harm. Whilst every hospital will have slightly different policies the fundamental goals of these include:

• The correct patient gets the correct operation on the correct side or part of their body. An appropriate

method of patient identification and patient marking must be in place. It must be clear to all involved in the procedure, particularly for operations on paired limbs or organs, when the incorrect side could be operated upon.

· The patient is protected from harm whilst under anaesthetic. When under a general anaesthetic the patient is vulnerable to a number of risks. Important amongst these are pressure effects upon nerves, for example those on the common peroneal nerve as it winds around the head of the fibula.

· Previous medical problems and allergies are identified and acted upon.

Prophylaxis

Infection

Infections remain a major issue for all surgical pro­cedures and the team caring for the patient needs to be aware of relevant risks and act to minimise such risks.

Before discussing the use of prophylactic antibiotics for the prevention of peri-operative infection, it is very important that issues of basic hygiene are discussed. Simple measures adopted by all those involved in patient care can make a real difference to reducing the risk of hospital-acquired infection. The very widespread and significant problems with antibi­otic organisms such as methicillin-resistant Staphylo-coccus aureus (MRSA) have reinforced the need for such basic measures.

· Wash your hands in between seeing each and every patient.

· Wear gloves for removing/changing dressings.

· Ensure that the hospital environment is as clean as possible.

These measures, especially hand washing, should be embedded into the psyche of those involved in patient care.

In addition to the very important matters of hygiene and appropriate sterile practice, antibiotics should be used in certain circumstances to reduce the risk of peri-operative infection. Each hospital will have individual policies on which particular antibiotics to use in the prophylactic setting (see Chapter 7, p. 51). It is also important to state that whilst the use of prophylac­tic antibiotics can, when used appropriately, signifi­cantly reduce infectious complications, inappropriate or prolonged use can leave the patient susceptible to infection with antibiotic resistant organisms such as MRSA.

Both factors related to the patient and the planned procedure governs the appropriate use of antibiotics in the prophylactic setting.

Procedure-related factors

Table 1 indicates the risk of post-operative wound infections with and without the use of prophylactic an­tibiotics. In addition to considering the absolute risk of infection the potential consequences of infection must also be considered; for example, a patient undergoing a vascular graft (a clean procedure) must receive ap­propriate antibiotic cover because of the catastrophic consequences of graft infection.

Patient-related factors

Patients with immunosuppression and pre-existing im­plants and patients at risk for developing infective en­docarditis must receive appropriate prophylaxis even when the procedure itself would not indicate their use.

Table 1. Risk of Post-Operative Wound Infection

Type of Procedure	Type of Procedure	Wound Infection Rate (%) Prophylactic antibiotics
		No	Yes
Clean	No contamination gastrointestinal, genitourinary and respiratory tract not breached	1-5	0-1
Clean-Contaminated	Gastrointestinal or Respiratory track opened but without spillage	10	1-2
Contaminated	Acute inflammation, infected urine, bile, gross spillage from gastrointestinal tract	20-30	10
Dirty	Establish infection	40-50	10

Venous thrombo-embolism

Deep vein thrombosis (DVT) is a not uncommon and potentially catastrophic complication of surgery. The risk for developing DVT ranges from a frac­tion of 1% to 30% or greater depending upon both patient- and procedure-related factors. Both patient-and procedure-related factors can be classified as low, medium or high risk (Table 2). High-risk patients un­dergoing high-risk operations will have a risk for DVT of up to 80% and a pulmonary embolism risk of 1-5% when prophylaxis is not used; these risks can be re­duced by at least one order of magnitude with appro­priate interventions.

Whilst a wide variety of agents have been trialled for the prevention of DVT, there are currently only three widely used methods:

· Graduated compression stockings: these stockings, which must be properly fitted, reduce venous pooling in the lower limbs and prevent venous stagnation.

· Heparin: this drug can be used in its conventional un-fractionated form or as one of the newer fractionated low-molecular-weight derivatives. The fractionated low-molecular-weight heparins offer the convenience of once-daily dosing for the majority of patients. It must however be remembered that the anticoagulant effect of the low-molecular-weight heparins cannot easily be reversed and, where such reversal may be important, standard unfractionated heparin should be used. • Mechanical calf compression devices: these machines work by intermittent pneumatic calf compression and thereby encourage venous return and reduce ve­nous pooling. The three methods are complementary and are often used in combination, depending upon the patient and operative risk factors (Table 2).

The systematic use of such measures is very impor­tant if the optimal benefit is to be made for the potential reduction in DVT.

Table 2. Prevention of deep vein thrombosis
		Operative risk factors
		Low (e.g. hernia repair)	Medium (e.g. general abdominal surgery)	High (e.g. pelvic cancer, orthopaedic surgery)
Patient risk factors	Low (age <40,> risk factors)	No prophylaxis	Heparin	Heparin and mechanical devices
	Medium (age >40, one risk factor)	Heparin	Heparin	Heparin and mechanical devices
	High (age >40, multiple risk factors)	Heparin and mechanical devices	Heparin And mechanical devices	Higher dose heparin, mechanical devices

Pre-operative care of the acute surgical patient

A significant number of patients will present with acute conditions requiring surgical operations. Whilst the principles outlined above are still valid, a number of additional issues are raised.

Informed consent

Whilst there is still a clear need to ensure that patients are appropriately informed, there are fewer opportu­nities to discuss the options with the patient and their family. In addition, the disease process may have re­sulted in the patient being confused. The team caring for the patient needs to judge carefully the level of in­formation required in this situation. Although it is very important that family members are kept informed, it has to be remembered that the team's primary duty is towards the patient. This sometimes puts the team in a difficult position when the views of the patient's family differ from that which the team caring for the patient hold. If such an occasion arises then careful discussion and documentation of the decision process is vital. In­creasingly, patients of very advanced years are admitted acutely with a surgical problem in the setting of signifi­cant additional medical problems. It is with this group of patients that specific ethical issues around consent and appropriateness of surgery occur. It is important that as full as possible a picture of the patient's overall health and quality of life is obtained and that a full and frank discussion of the options, risks and benefits takes place.

Pre-operative resuscitation

It is important that wherever possible significant fluid deficits and electrolyte abnormalities are corrected prior to surgery. There is often a balance to be made between timely operative intervention and the degree of fluid resuscitation required. An early discussion be­tween surgeon, anaesthetist and, when required, inten-sivist can help plan timing.

Pre-existing medical co-morbidities

There is clearly less time to address these issues and it may not be possible to address significant ongoing medical problems. Clearly such co-morbidities should be identified, and all involved with planning the oper­ation should be informed. The issues are most acute for significant cardiac, respiratory, hepatic or renal disease.

Pre-operative nutrition

An awareness of the nutritional status of patients is im­portant and such awareness should guide the decisions about nutritional support (see Chapter 5).

Before operation the malnourished patient should whenever possible be given appropriate nutritional support. There is no doubt that significant pre-operative malnutrition increases the risk of post­operative complications (> 10-15% weight loss). If possible such nutrition should be given enterally, re­serving parenteral nutrition for the minority of patients in whom the gastrointestinal tract is not an option. Parenteral nutrition is associated with increased costs and complications and is of proven benefit in the se­riously malnourished patient only, when it should be given for at least 10 days prior to surgery for any bene­fits to be seen. There is increasing evidence that enteral feeds specifically formulated to boost certain immune parameters offer clinical benefits for patients about to undergo major surgery.

After operation any patient who is unable to take in normal diet for 7 or more days should receive nutri­tional support, which as before operation should use the enteral route whenever possible.

Specific pre-operative issues

Stomas

A number of gastrointestinal operations will require the use of a temporary or permanent stoma (see Chap­ter 30). Prior to operation it is important that the pa­tient is fully informed of the likelihood/possibility of a stoma. Clearly there will be operations that result in a stoma which could not be predicted being formed but such occasions should be very rare.

The concept of having an intestinal stoma is regarded by most patients as one of the most daunting aspects of facing surgery. Prior to surgery the patient should be seen by an experienced stoma/colorectal nurse to discuss in detail the nature of the stoma, the type of appliances likely to be used and the optimal site for its placement. The nurse specialist plays a very important role both in the immediate peri-operative period and beyond.

Diabetes mellitus

Diabetes mellitus is one of the most frequently seen medical co-morbidities which complicate peri-operative care. It is clearly important that patients with diabetes mellitus are appropriately worked up for surgery.

In the weeks leading up to elective surgery the man­agement of the diabetes should be reviewed and blood glucose control optimised. Particular attention should be paid to cardiovascular and renal co-morbidities dur­ing the pre-operative assessment.

Generally patients with diabetes should be sched­uled for surgery in the morning. For patients taking oral hypoglycaemic drugs, the drugs should be stopped the night before surgery and the blood glucose moni­tored. Patients with insulin-dependent diabetes should be commenced on an intravenous infusion regimen. There are two approaches to this:

· Variable-rate insulin infusion. The patients blood glucose levels are monitored regularly and the rate of insulin infusion adjusted. An infusion of dextrose is continued throughout the period of insulin infu­sion.

Single infusion of glucose insulin and potassium (GIK). Whilst this method has the advantage of sim­plicity it is not possible to adjust the rates of glucose and insulin infusion separately and the technique can lead to the administration of excessive amounts of free water. The variable-rate infusion is the most widespread ap­proach and although more involved in terms of mon­itoring offers better glycaemic control; this in itself is associated with better patient outcomes.

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