CHAPTER 1 Perioperative anesthetic care 24 Pulmonary arterial pressure Pulmonary wedge pressure 30 20 10 0 30 20 10 0 30 20 10 0 Central venous pressure Pressure waveforms encountered during insertion of pulmonary artery catheter (from Kalia an d Webster, 2001) 30 20 10 0 Right ventricular pressure Fig. 1.5 Placement of pulmonary artery catheter showing related pressure valves Technique (cid:142)(cid:3) Choose the appropriate size airway (Fig. 1.6) by placing the air way between tip of tragus and angle of mouth. A large airway can itself cause the obstructi on whereas a smaller than ideal airway will not be able to remove the obstruction. (cid:142)(cid:3) Open the mouth, depress the tongue, and slide the airway posteriorly betwe en tongue and hard palate, with concavity facing the front, until the flange is positioned and rests between lips and the teeth. (cid:142)(cid:3) In case of difficulty the airway can be inserted with concavity facing the hard palate. At the first point of resistance the airway should be rotated by 180 and pus hed downwards gently till the flange rests between lips and teeth. Avoid this technique in small children as it can cause trauma to soft palate. Nasopharyngeal airway insertion Patients with intact pharyngeal reflexes tolerate nasophary ngeal airways better than oropharyngeal airways. Technique (cid:142)(cid:3) Check the paten cy of nostrils and choose the nostril with greater patency. (cid:142)(cid:3) Lubricate the nasopharyngeal airway with jelly and insert in downward and posterior direction till the flange rests in front of the nostril. POSTOPERATIVE COMPLICATIONS1 25 Fig. 1.6 Guedal \200\231s airways Laryngeal mask airway (LMA) It is introduced through the oral cavity after induction of ane sthesia. The laryngeal mask (Fig. 1.7) rests in front of the laryngeal inlet. It provides h ands-free clear airway and obviates the need for tracheal intubation, thereby avoiding all the complications of intubation. It offers no protec- tion from aspiration of gastric conte nts. Indications (cid:142)(cid:3) Provision of a clear airway overcoming the need to hold a facemask. (cid:142)(cid:3) Avoidance of tracheal intubation in a spontaneously breathing p atient. (cid:142)(cid:3) Airway maintenance in known or suspected cases of difficult intuba tion. (cid:142)(cid:3) Emergency management of failed intubation. (cid:142)(cid:3) Provisio n of a temporary airway during cardiopulmonary resuscitation. The LMA does not protect agai nst aspiration of gastric contents. In pa- tients with a full stomach, delayed gastric empt ying, gastro-oesophageal reflux, or a hiatus hernia, the use of a LMA is contraindicated. T echnique (cid:142)(cid:3) Adequate depth of anesthesia/suppression of airway reflexes shoul d be established. (cid:142)(cid:3) Extend the patient \200\231s head and open mouth. It may be necessary to hold down the lower jaw. (cid:142)(cid:3) Introduce the LMA into the oro-pharynx using a gloved finger. It is gently advanced along the hard palate until the tip of the cuff reaches the posterior phary ngeal wall. Advance it distally into the laryngo- pharynx until the cuff sits posterior to the larynx. (cid:142)(cid:3) When correctly positioned, inflate the cuff and the LMA is connected to a breathing system and secured. (cid:142)(cid:3) Confirm correct placement by manual inflation of the lungs or by observation of movement of a reservoir bag in spontaneously breath- ing patients. CHAPTER 1 Perioperative anesthetic care 26 Fig. 1.7 Laryngeal mask airway Orotracheal intubation A definitive airway requires placement of a cuffed tube in the trach ea. The tracheal tube (Fig. 1.8) is made of PVC and is radio-opaque. Most male patients req uire size 9 whereas female patients need size 8 tracheal tubes. Tracheal tube has a low pre ssure cuff designed to provide an airtight seal after inflation with air. Appropriate size and length of orotra- cheal tube in the children can be calculated by the formulas. Age Age Size = + 4.5mm Length = + 12cm 4 2 Technique (cid:142)(cid:3) Check the laryngoscope and ensure that cuff of the tracheal tube is not leaking. (cid:142)(cid:3) Induce the conscious patient with an appropriate induction agent and muscle relaxant should be used to facilitate intubation. (cid:142)(cid:3) Position the patient in \200\230sniffing the morning air position \200 \231 (flexion of neck by placing a 4 inch thick pillow under the occiput and extension at atlanto-occipital joint). Avoid manipulation of the neck in the patients with suspected cervical spine injury . (cid:142)(cid:3) Introduce the blade of the laryngoscope from right side of the mouth. Displace the tongue to the left by the flange of laryngoscope. (cid:142)(cid:3) Keep sliding the spatula of the blade on the tongue until the epiglottis is visualized. (cid:142)(cid:3) Tip of the blade should rest in the vallecula (junction of epiglottis and the base of tongue). Lift the laryngoscope in the direction of the handle. (cid:142)(cid:3) Identify the laryngeal inlet by the vocal cords and insert the tracheal tube gently into the trachea. Inflate the cuff of the tube with air, enough to prevent the audible leak of gasses on positive pressure ventilation. (cid:142)(cid:3) Confirm the place ment of the tube by auscultation and capnography. POSTOPERATIVE COMPLICATIONS1 27 Fig. 1.8 Endotracheal tube Indications for intubation (cid:142)(cid:3) Unconscious patient (cid:142)(cid:3) Risk of as piration (patient with full stomach) (cid:142)(cid:3) Mechanical ventilation (apnoea, intra thoracic surgery) (cid:142)(cid:3) Operations with difficult airway access (ENT, prone posi tion). Complications of intubation (cid:142)(cid:3) Trauma to face, lips, tongue, and teeth (cid:142)(cid:3) Hypertensive response (cid:142)(cid:3) Arrhythmias. Cricothyroidotomy Thi s procedure requires an opening in the cricothyroid membrane and the airway can be secured by placing the tube in the trachea through this opening. Cricothyroidotomy is a life-saving procedure in a patient with airway obstruction where airway access is impossible through t he oro- pharyngeal or nasopharyngeal route. Cricothyroidotomy can be per- formed with the h elp of a needle or a proper tube can be introduced through the membrane using Seldinger \200\231s technique. Technique (cid:142)(cid:3) Stabilize the cricothyroid membrane (extend s between thyroid and cricoid cartilage) between thumb and index finger and puncture with a 12 or 14 needle conne cted with a saline filled syringe. (cid:142)(cid:3) Advance the needle at 45 angle until air is aspirated freely. (cid:142)(cid:3) Connect the needle to an oxygen source. (cid:142) (cid:3) Occlusion of the hole in the connecting tubing causes inflation of the chest and oxygenation of the patient. Inflate for one second and deflate for four seconds. Elimination of carbon dioxide is inadequate with this CHAPTER 1 Perioperative anesthetic care 28 technique and formal tracheostomy should be done within 45 minutes of this procedure to est ablish normal ventilation otherwise the patient will become hypercapnic. (cid:142)(cid:3) Seldinger \200\231s technique consists of the introduction of a J tipped w ire through the needle once the tip of the needle is in the trachea. The needle is withdraw n and the dilator and cricothyroidotomy tube as- sembly is railroaded over the J wire. The dilator and J wire is with- drawn leaving the tube in the trachea. (cid:142)(cid:3) Confirm the placement of the tube by auscultation and capnography. Complic ations (cid:142)(cid:3) Haematoma (cid:142)(cid:3) Aspiration (cid:142)(cid:3) Perforation of posterior wall of trachea (cid:142)(cid:3) Hoarseness (cid:142)(cid:3) Hemorrhage (cid:1 42)(cid:3) Subglottic stenosis (cid:142)(cid:3) Surgical emphysema (cid:142)(cid:3) False p assage. Tracheostomy (see Chapter 15) Chapter 2 29 2 Theater procedures and prophylaxis David J. Leaper Theater discipline 30 Patient care in operating theater 32 Day case surgery 34 Evaluation of X-rays in surgery 36 Prophylaxis of deep vein thrombosis 38 Antibiotic pr ophylaxis 40 Bowel preparation 42 HIV and AIDS precautions 44 CHAPTER 2 Theater procedures and prophylaxis 30 Theater discipline There are many time-honored procedures in theater which do not have an a ccepted evidence base. Nevertheless it would flaunt danger to disregard them, particularly as we currently enjoy the lowest figure of morbidity and mortality despite operating on a s icker and old cohort of patient. There are some downsides; the increase of emergent and res is- tant organisms such as Cl. difficile and MRSA serve as examples. Theater design and ventilation (cid:142)(cid:3) Modern operating theaters must be safe envi ronments for patients and staff. Ideally they should have easy access to A&E, HDU, and ITU and general wards, with easily opened links to radiology and laboratories. High maintenance is required, not just for infection control, but for lighting, operating tables, anestheti c machines, and other equipment. (cid:142)(cid:3) In general, operating theater air is changed 20 times an hour using filter s. The positive pressure (plenum) ceiling mounted, ventilation should ideally be of laminar flow to avoid turbulence. Ultraclean air, air changes up to 40 times per hour, and the use of exhaust suits in Charnley theaters is appropriate for orthopedic operations when contam ination can be disastrous. The evidence that such attention to ventilation is more effectiv e than prophylactic antibiotics however is lacking. There must be satisfactory cleaning bet ween lists and it is illogical to use designated orthopedic theater for dirty operations. ( cid:142)(cid:3) Microbiological testing is undertaken regularly using a slit samplers. When there are outbrakes of resistant organisms, theaters may be need to be closed and steriliz ed, if they are the source, with infection control procedures to identify and treat carrier s. Septic lesions on patients and staff should be reason to prevent their entry. (cid:142)(cid:3) Ceiling-mounted gasses and vacuum facilities need similar maintenance and attention to infection control measures. It is impossible to connect the wrong gasses t o an anesthetic machine. Most theaters have temperature and humidity control for both patie nt safety and staff comfort. Some theaters are fortunate enough to have some natural light but dignity and privacy must be ensured. It is appropriate to encourage as few personnel to be present in theater and ensure as little movement as is practical. Theater clothing (cid:142)(cid:3) Vests, trousers and skirts are usually made of comfortabl e light cotton (ventiles) which can be used for a whole list of operations, unless they bec ome soiled. It is inappropriate to use theater clothing for trips to the ward or A&E, unles s there is an emergency. On return, clothing should be changed; all hospitals see large amo unts of linen disappear each year. Clogs or shoes are comfier than boots for many, but must be antistatic. Boots are appropriate for at risk operations, such as an HIV risk, or when there is gross contamination (when aprons should also have been anticipated). theater DISCIPLINE1 31 (cid:142)(cid:3) The use of caps and masks, in particular, is controversial. The control of hair is logical but both caps and masks afford protection to the staff from contamination. Masks and caps may be more important in prosthetic orthopedic and vascular operations. Mas ks should not be handled and replaced \200\224they are disposable, one per operation. (cid:142)(cid:3) Gowns and operating drapes can be cleaned, repaired and reautoclaved many times. They are less expensive than waterproof disposables (see HIV preca utions) which can be justified in prosthetic surgery. The included cellulose is water-resis tant but make gowns uncomfortable to wear in long operations. (cid:142)(cid:3) Aqueous antiseptics, chlorhexidine, triclosan, or povidone iodine (Betadin e) are used for hand preparation prior to gowning up. Scrubbing the nails is only necessary for the first case on a list. Scrubbing the skin or repeat scrubbing risks contamination b y deep skin organisms. After the first 4 \200\2235 minutes hand preparation (scrub-up), han d disinfection can be a simple hand washing between cases with antiseptic or a hand rub usi ng an alcoholic preparation, unless there has been contamination. Alcoholic chlorhexidine a nd povidone iodine are used for patient skin preparation. Two applications should reduce re sident flora by more than 95%. The use of incised drapes (adhesive polyurethane films), wou nd guards and drains has not been shown to reduce infection rates. If shaving is considered necessary it should be undertaken immediately prior to surgery or a depilatory cream can b e used. Skin contamination is increased after shaving and may double the infection rate if shaving is undertaken >12 \200\22324 hours before surgery. The main reason for shaving is t o facilitate removal of adhesive dressings. (cid:142)(cid:3) The use of heat for sterilization is not particularly effective but steam under pressure (100 \200\223200kPa and 121 \200\223143 C) can kill all micro- organi sms and spores and is very penetrative and therefore useful in sterilizing materials and so me instruments. Short cycle autoclaves are used in central sterile supply after cleaning an d repairing equipment and linen. (cid:142)(cid:3) Disposable materials used in operation, for example, suture materials are sterilized by manufacturers in large (and expensive) gamma radiation units. Ethylene ox ide is not used as it is explosive. Endo- scopes and other delicate re-useable instruments need to be sterilized after cleaning by immersion in an antiseptic. Glutaraldehyde has been superseded by less toxic agents. CHAPTER 2 Theater procedures and prophylaxis 32 Patient care in operating theater Patients \200\231 consent must be taken by the operating surgeon or an experi- enced appropriate surrogate. It must be taken without coercion with a full explanation of the procedure intended, its benefits, and possible complications. Pati ents must have the opportunity to ask questions about the surgery and anesthetic and discus s alternatives. (cid:142)(cid:3) The explanation of every complication presents difficulty but devastating complications, however rare, such as recurrent nerve damage during thyroid lobe ctomy, must be included. (cid:142)(cid:3) Each patient must be identified and an operating site or side marked befor e any premedication. Identity bracelets must match the notes, ID number, and what the patie nt says. Preoperative marking must use an indelible pen. Identification occurs on leaving t he ward for surgery, at admission to the theater and in the anesthetic room. The surgeon sh ould identify the patient and his/her marking before anesthesia begins. The correct operati on should be confirmed and that marking must be clear. Any doubt should mean the patient sh ould be returned to the ward. (cid:142)(cid:3) Patients, and instruments, flow from \200\230clean to dirty \200\231 in a set pattern during the operating theater stay. There are no new mistakes to make, we simply must try to avoid the time honored ones. Once asleep or positioned on the operating table, it is the a nesthetist \200\231s responsibility, for example, to look after an arthritic cervical spine and the surgeon \200\231s responsibility to prevent damage to the lateral peroneal nerve i n the Lloyds-Davies position, the ulnar nerve if arm boards are used and the brachial plexu s if the arm is placed above the head. Pressure relieving aids must ensure bony prominences are protected from the risk of pressure sores. The patient must be secure, particularly if the table is tilted, and calves protected by the use of the heel pad. (cid:142)(cid:3) Hypothermia is common during long general anesthetics, particularly when t here is exposure. Hypothermia adds to postoperative complica- tions, the risk of pressure s ores, and wound infection. Core tempera- ture, based on tympanic or oesophageal probes, can be maintained by the use of warmed IV fluids and either a forced warm-air blanket or warmi ng mattress. (cid:142)(cid:3) Diathermy must be well maintained and should not be used if unfamil- iar. It provides a high frequency alternating current of 400kHz which at the active electrode ca n produce heat up to 1000 C. In monopolar diathermy the indifferent plate must be checked with full contact to prevent burns. It is the surgeon \200\231s responsibility. Bipolar dia thermy has both active and indifferent electrodes at the surgeon \200\231s fingertips and a llows much more precision. Lasers need designated staff and must be operated with strict gu idelines, including protective eye glasses and clear communication when being used. This page intentionally left blank CHAPTER 2 Theater procedures and prophylaxis 34 Day case surgery Day case surgery is by no means a recent concept but there is now strong e vidence to show that 75% of elective surgery can be performed safely, according to the Brit ish Association of Day Surgery and the Audit Commission (the so-called \200\230basket \200 \231 and \200\230trolley \200\231 of procedures). It may be extended into 24 hour faciliti es. This certainly fits with patient choice, allows seamless booking, and early return to w ork. For success it must be faultlessly driven by multidisciplinary and agreed protocols. N urse assessment and discharge with pain relief and aftercare are shown to be highly effecti ve. There is a culture change need to ask \200\230is there any reason not to do elective s urgery as a day case? \200\231 Apart from surgeon, nurse, and patient choice it is very cost effective and is ringfenced f rom invasion by medical admissions. Ideally the unit should be a stand alone, purpose built facility. All specialities in surgery can benefit and waiting lists can become controlled or ideally abolished and replaced with a diary system. This page intentionally left blank CHAPTER 2 Theater procedures and prophylaxis 36 Evaluation of X-rays in surgery (cid:142)(cid:3) Imaging has become an indispensable adjunc t to surgical procedures. They can be the road map to decision making and the approach and choice for an operation. Most hospital Trusts now have a weekly X-ray meeting at which deci sions should be enabled preoperatively, as in cancer multidisciplinary meetings. Difficult imaging, particularly with real-time ultrasound, CT, and MRI can be interpreted together at these meetings. Radiologists are very friendly to surgeons and we need to be to them, part icularly when CT is asked for at 2 a.m.! They can be approached for interpretation of emerg ency chest and abdominal X-rays but a personal touch is recommended! A chest X-ray can help you plan and consider postoperative care including physiotherapy but a radiologist can sho wn you that an erect plain abdominal X-ray may not help interpretation of intestinal obstru ction. Always take their advice. (cid:142)(cid:3) Radiologists can bale out the need for emergency surgery and interventional radiology is a fulfilling career; as examples, the rise of endovascular aneu rysmorrhaphy and guided aspiration of abdominal abscesses. Surgeons may take X-rays themsel ves in theater, cholangiograms for example. To do this, it is imperative that the operator holds an irradiation protection certificate. Full radiation protection with gowns and exclu sion of unnecessary staff must be complied with, including the cooperation of radiographers , radiologists, and planning of their time. Don \200\231t expect support at the last minute unless it is a true emergency. Planning should also make it clear to pregnant staff that t hey should avoid that operation on that particular day. It may be overlooked and then an op eration has to be canceled. This page intentionally left blank CHAPTER 2 Theater procedures and prophylaxis 38 Prophylaxis of deep vein thrombosis (cid:142)(cid:3) Deep vein thrombosis (DVT) is an avoid able complication. Before prophylaxis 40 \200\22350% of patients undergoing total hip replacement for example would h ave a thrombosis in the soleal sinuses of the calf, or more proximal with a pulmonary embol us (PE) rate of 1 \200\22310%. Risk factors relate to hypercoagulability and the fibrinolyt ic system which depends on the balance of thrombin and antithrombin, tissue plasmi- nogen a ctivator (tPa) and plasminogen activator inhibitors (PAIs). Patients with genetic defects o f protein C and S, and factor V Leiden defect for examples have the perioperative risk of h ypercoagulability. The list of common clinical risk factors is shown in Table 2.1. In pregn ancy it is always best to defer surgery and the stopping of HRT is logical. The effect of t he pill, particularly low estrogen types, is controversial. Common sense dictates cessation but not at the increased risk of pregnancy. Consult local agreed protocols. (cid:142)(cid:3) Diagnosis may be made clinically on classic signs but suspicion can be strengthened or confirmed by measuring D-dimers, contrast or isotope venography, duplex Dop pler, or plethysmography. Local protocols usually apply. (cid:142)(cid:3) Prophylaxis includes early mobilization but in any level of risk thromboembolic deterrent (TED) stockings should be considered. In moderate to higher risk, intermittent calf compression or foot pumps should be used intraoperatively with prophylact ic heparin in addition or in combination. Warfarin and aspirin probably have no role in pro phylaxis. (cid:142)(cid:3) Low molecular weight heparin (LMWH) given once a day subcutane- ously is now the prophylaxis of choice. It is associated with a minimum risk of bleeding an d has replaced unfractionated calcium heparin. There is strong evidence based support for i ts use. For example tinzaparin can be given at 3500U daily subcutaneously, and in the case of DVT can be boosted as treatment until anticoagulation with warfarin is established. (cid:142)(cid:3) Local protocols must be consulted but Table 2.2 gives a template for DVT prophylaxis. PROPHYLAXIS OF DEEP VEIN THROMBOSIS1 39 Table 2.1 Perioperative clinical risk factors for deep vein thrombosis (cid:142)(cid:3) Age (> 40 years, even more > 70 years) (cid:142)(cid:3) Obesity (BMI > 40) (cid:142)(cid:3) Immobilization (stroke or cardiac failure) (cid:142)(cid:3) Malignancy (p elvic) (cid:142)(cid:3) Pregnancy, the pill, HRT (estrogen related) (cid:142)(cid:3) Sepsis and chronic inflammatory diseases (cid:142)(cid:3) Metabolic (diabetes, anemia) (cid:142)( cid:3) Orthopedic (THR and knee surgery) (cid:142)(cid:3) Previous thromboembolic disease Table 2.2 Recommended DVT prophylaxis Clinical risk Prophylaxis Minor surgery Major surgery age >40 years Minor illness Mobilization Care in theater TEDs Low Major surgery age >40 years Major illness Minor surgery with known risks As low risk (TEDs) Plus LMWH or calf compression Moderate Hip knee pelvic surgery Major cancer resection Known hypercoagulability Previous DVT/PE TEDs Plus LMWH Plus calf compression High Consider full dose IV heparin control in highest risk during withdrawal of warfarin and ear ly postoperative period (discuss with hematologists). CHAPTER 2 Theater procedures and prophylaxis 40 Antibiotic prophylaxis (cid:142)(cid:3) The principles of antibiotic prophylaxis were laid down in the experi- ments of John Burke in the 1960s. If an appropriate antibiotic was given to an animal prior to an inoculation of Staph. aureus subsequent abscess formation was reduced. He described a decisive period when antibiotics protected against the development of infection whilst ho st defenses were mounted in the four hours after the first incision. Since then many clinic al trials have proven the worth of prohphylactic antibiotics to prevent wound infection (su perficial surgical site infection \200\224SSSI). They do not prevent wound or anastomotic f ailure but may reduce the risk of deep surgical site infections and intra- abdominal absces ses. (cid:142)(cid:3) Modern antibiotic prophylaxis gives empirical cover against the organ- isms expected at operation. Cover beyond 24 hours is not prophylaxis and should not exceed three doses (when it would be therapy). Wounds are classified into four categories (Table 2 .3); prophylaxis is not appropriate for dirty wounds which need antibiotic therapy. Added r isk factors are listed in Table 2.4. (cid:142)(cid:3) Local protocols ought to be adhered to otherwise there is a risk of antibiotic resistance. There may be rotating antibiotic policies in place and this should h ave been addressed by local clinical governance. Antibiotics are only an adjunct to surgica l care and must be coupled to careful and gentle, meticulous surgery with perfect haemostas is. Theater discipline must be obeyed, particularly in prosthetic surgery where strict asep sis is critical. (cid:142)(cid:3) In clean surgery without a prosthetic implant, antibiotic prophylaxis has not been proven to be effective. However, close surveillance of clean wound surgery into pr imary health care (where most infections occur or are detected) reveals a wound infection r ate, albeit of minor nature, of up to 10%. Prophylaxis is effective in prosthetic surgery ( where any surgical site infection is a disaster) and in clean-contaminated and contaminated wounds. Dirty surgery needs treatment for a minimum of 3 \200\2235 days. Suggested regimen s are shown in Table 2.5, p43. (cid:142)(cid:3) In prosthetic surgery the major risk is from endogenous skin organisms (St aph. aureus and CNS), particularly those which are slime producers or when there is a biofi lm production. There is a larger risk from resistant forms (Table 2.5). When a viscus is op ened there is a risk from many other organisms, particularly the aerobic Gram-negative baci lli (AGNB) and anaerobes (mostly Bacteroides spp) which act in synergy. (cid:142)(cid:3) Patients who have rheumatic heart disease need prophylaxis for even minor procedures such as dental treatment and certainly invasive endoscopy (ERCP or urinary tract instrumentation). In endoscopic procedures a broad spectrum penicillin or second generatio n cephalosporin is recommended. Patients who have a splenectomy need pneumovax vaccination against pneumococcus with lifetime penicillin cover. ANTIBIOTIC PROPHYLAXIS1 41 Table 2.3 Types and examples of surgical wounds (cid:142)(cid:3) No viscus opened (cid:142)(cid:3) No inflammation (cid:142)(cid:3) No brea ch in asepsis (cid:142)(cid:3) Viscus opened (cid:142)(cid:3) Minimal spillage (cid:142)(ci d:3) Viscus opened (cid:142)(cid:3) Inflammatory disease (cid:142)(cid:3) Significant spill age (cid:142)(cid:3) Pus encountered (cid:142)(cid:3) Perforation (cid:142)(cid:3) Varicose veins (cid:142)(cid:3) Prosthetic, vascular, or orthopedic surger y Clean (cid:142)(cid:3) Open cholecystectomy Clean-contaminated (cid:142)(cid:3) Elective colorectal Contaminated surgery (cid:142)(cid:3) Fecal peritonitis (needs therapy) Dirty Table 2.4 Risk factors for surgical infection (cid:142)(cid:3) Poor perfusion \200\224(local ischaemia; shock of any cause) (cid:142)(cid :3) Malnutrition \200\224(low albumin; obesity) (cid:142)(cid:3) Poor surgery \200\224(haem atoma; tension) (cid:142)(cid:3) Metabolic diseases \200\224(diabetes, uraemia, jaundice) ( cid:142)(cid:3) Immunosuppression \200\224(steroids; cancer, chemo/radiotherapy) (cid:142)( cid:3) Perioperative care \200\224(poor hygiene/hand washing, shaving. CHAPTER 2 Theater procedures and prophylaxis 42 Bowel preparation (cid:142)(cid:3) This must be considered for elective colorectal surgery, although many consider it unnecessary for right colon procedures. In obstruc- tion intraoperative la vage may permit safe primary anastomoses. The Herculean attempts in the past to completely empty the bowel (5 days of enemas, magnesium sulfate, Epsom salts, mannitol, 10 litres of n asogastric saline) have been replaced by single sachets of cathartics such as Picolax. Thes e should be given 12 \200\22324 hours before surgery but (i) respect the dignity of a patie nt who may be \200\230glued \200\231 to a toilet for 8 hours and (ii) remember obstruction may be induced, so carefully watch the patient for pain and abdominal distension and alway s ensure good hydration. (cid:142)(cid:3) Low residue diet for 5 days preoperatively may actually reduce patients fl uid intake; this and attention to nutrition are equally important. Beware of the patient wh o has had a recent weight loss of 10 \200\22320%. The additional use of poorly absorbed ant ibiotics is controversial. Regard local protocols. (cid:142)(cid:3) Stoma siting must also be undertaken in the 24 hour preoperative period. E ven in an anterior resection markings for an LIF end colos- tomy (following the unexpected need for a Hartmann \200\231s operation) or an RIF loop ileostomy (to dysfunction the dista l anastomosis) should be considered. Table 2.5 Suggested prophylactic regimens for operations at risk Types of surgery Organisms encountered Prophylactic regimen suggested (cid:142)(cid:3) Vascular (cid:142)(cid:3) Staphlococcus epidermidis (or MRCNS) (cid:142)(cid:3) Staphylococcus aureu s (or MRSA) (cid:142)(cid:3) Aerobic Gram-negative bacilli (AGNB) (cid:142)(cid:3) 3 doses flucloxacillin genamicin, vanomycin or rifampicin if MRCNS/MRSA a risk (cid:142)(cid:3) Orthopedic (cid:142)(cid:3) Staphylococcus epidermidis/aureus (cid:142)(cid:3) 1 \200\2233 doses wide-spectrum cephalosporin (with antistaphylococcal action) (cid:142)(cid:3) Gentamicin beads (cid:142)(cid:3) Oesophagogastric (cid:142)(cid:3) Enterobacteriaceae (cid:142)(cid:3) Enterococci (including anaerobic/virid ans (cid:142)(cid:3) 1 \200\2233 doses second-generation cephalosporin and metronidazole in severe contamination Streptococci) (cid:142)(cid:3) Biliary (cid:142)(cid:3) Enterobacteriaceae (mainly E. coli) (cid:142)(cid:3) Enterococci (includin g Streptococcus faecalis) (cid:142)(cid:3) 1 dose second-generation cephalosporin B O W (cid:142)(cid:3) Small bowel (cid:142)(cid:3) Enterobacteriaceae (cid:142)(cid:3) Anaerobes (mainly Bacteroides) (cid:142)(cid:3) 1 \200\2233 doses second-generation cephalosporin (cid:140) metronidazole E L (cid:142)(cid:3) Appendix/colorectal (cid:142)(cid:3) Enterobacteriaceae (cid:142)(cid:3) Anaerobes (Bacteriodes streptococci) (cid:142)(cid:3) 3 doses second-generation cephalosporin (alternatively gentamicin) with me tronidazole (oral, poorly absorbed antibiotics controversial) P R E P A R A T O N All regimens are intravenous and should start preoperatively. In elective operations, antib iotics can be given at induction of anesthesia. In emergency operations (or in contaminatio n during elective surgery) antibiotics should be given at diagnosis and prolonged as therap y for 3 \200\2235 days if necessary. I 1 4 3 CHAPTER 2 Theater procedures and prophylaxis 44 HIV and AIDS precautions (cid:142)(cid:3) All medical and nursing staff are now expected to be immunized against hepatitis B. The current vaccination schedules use a genetically engineered antigen ; three doses usually give good antibody levels with five year boosters. There is no vaccin ation yet against the non-B hepatitis viruses. (cid:142)(cid:3) Theater precautions when operating on a patient who is, or who is at risk of being HIV positive, should always be preceded by the question, \200\230is this operatio n really necessary? \200\231 There will be local infection control guidelines. (cid:142)(cid:3) Theater should be calm and contain as few personnel as possible with the o peration probably at the end of a list with extra time allotted. Eye contact must be kept b etween the operating team with all instruments passed to and fro in a kidney dish. Glasses or a visor are needed by the whole team and as many disposables used (gowns, drapes, instru ments etc.) as possible. Needle stick injuries can be minimized by double glov ing and boot s are more protective than clogs. Haemostasis should be meticulous with every effort made a nd anticipated to avoid spillage of body fluids. (cid:142)(cid:3) Surgeons who become HIV positive for any reason need pro- fessional advice on their limitations and modification of their presence in operative surge ry. Chapter 3 45 f3 Anatomy for surgeons F. Di Franco and G. R. McLatchie The female breast 46 The endocrine system 48 The respirato ry system 52 The abdominal wall 58 The digestive system 64 The appendix 72 The rectum 74 Th e anal canal 76 The liver 78 The gall bladder and bile ducts 82 The pancreas 84 The genitou rinary system 86 CHAPTER 3 Anatomy for surgeons 46 The female breast Breasts are bilateral skin appendages that vary individually in size and shape. Embryology The breast arises from the mammary ridges that derive from the ectoderm. Surface markings The breast is contained within the superficial fascia. It rests on the pec toralis major extending: (cid:142)(cid:3) Superiorly to the 2nd rib. (cid:142)(cid:3) Infer iorly to 6th rib. (cid:142)(cid:3) Medially to the sternum. (cid:142)(cid:3) Laterally to m id axillary line. The axillary tail is an extension of breast tissue into the axilla. Structural features The breast is composed of lobules. Within each lobule, glandular tissue is placed centrally whereas adipose tissue tends to be more laterally. The glands form a d uctal system terminating in 15 \200\22320 lactiferous ducts radiat- ing towards the nipple. Each lobe is separated by fibrous septa, a colla- genous membrane that supports the glandu lar structure. The fibrous septa, along with the ligament of Cooper, form the suspensory me cha- nism of the breast by their attachment to the ribs and the skin. Blood supply Arterial (cid:142)(cid:3) Axillary artery via lateral thoracic and acromiothor acic branches. (cid:142)(cid:3) Internal mammary artery via its perforating branches. Venou s (cid:142)(cid:3) Venous plexus underneath the areola that drains towards the axillary vei n. (cid:142)(cid:3) Veins draining towards the internal mammary vein. Lymphatic drainage (cid:142)(cid:3) The lymphatics of the nipple drain along the surface of the breast underneath the skin. (cid:142)(cid:3) The lymphatics from the medial aspect of the breast drain towards the nodes of the internal mammary territory. (cid:142)(cid:3) Most of the lymphatics of the breast drain toward the axilla. The majority of the lymph nodes are located in the territory of the axillary vein. Nerve supply It arises from the anterior and lateral branches of the 4th, 5th, and 6th thor acic nerves. Practical hint The status of the axillary lymph nodes is crucial in management of breast ca ncer because: (cid:142)(cid:3) It is a prognostic factor. (cid:142)(cid:3) It determines th e need for adjuvant treatment. THE FEMALE BREAST1 47 Fascia superficialis \200\224 superficial layer Retromammary space Pectoralis minor Suspensory ligament Glandular tissue Pectoralis major Lobules of fat Intercostal muscles Fascia superficialis \200\224 deep layer Axillary tail of the breast Nipple UI = Upper internal quadrant UE = Upper external quadrant LI = Lower internal quadrant LE = Lower external quadrant UI UE LI LE Areola Fig. 3.1 The female breast CHAPTER 3 Anatomy for surgeons 48 The endocrine system The thyroid gland This gland is highly vascular, enclosed in a fibrous capsule and bound by a sheath of pretracheal fascia to the larynx so it moves up and down during swallowing. Structure (cid:142)(cid:3) Right and left lobes \200\224pear-shaped, they lie at the sides of the larynx and trachea. (cid:142)(cid:3) An isthmus \200\224connects the right and left lobe at the level of the second, third, and fourth tracheal rings. (cid:142)(cid:3) A pyramidal lobe \200\224often projects upwards from the isthmus. Relation s (cid:142)(cid:3) Superficial: Sternothyroid, sternohyoid, omohyoid and their nerves from the ansa hypoglossi. These are overlapped below by the sterno- mastoid. (cid:142)(cid:3) Medial: Cricoid cartilage, thyroid cartilage, inferior constrictor above and recurrent laryngeal nerve. (cid:142)(cid:3) Posterior: Carotid sheath, inferior thyroid artery, prevertebral muscles. Blood supply (cid:142)(cid:3) Arterial Superior thyroid artery. This is the first branch of the external carotid. It passes to the upper pole under the infrahyoid muscles close to th e ex- ternal branch of the superior laryngeal nerve. Damage to the nerve leads to loss of t imbre of the voice, which becomes monotone. The superior pedicle should therefore be tied c lose to its origin. Inferior thyroid artery. It arises from the thyrocervical trunk, a bran ch of the subclavian artery. It ascends to the carotid sheath and enters the posterior part of the gland. The inferior pedicle should be tied well out to avoid recurrent laryngeal ne rve damage. (cid:142)(cid:3) Venous Superior thyroid vein emerges from the upper pole and d rains into the internal jugular vein. Middle thyroid vein from the lower part of the latera l border of the lobes crosses the common carotid and drains into the internal jugular vein. Inferior thyroid vein from the isthmus or lower medial lobe passes along the front of the trachea to the left innominate vein. Lymphatic drainage To the middle and lower deep jugular, pretracheal, and mediastinal nodes . Recurrent laryngeal nerve Arises from the vagus and runs upwards in the tracheo-oesophageal groove behind or in front of the inferior thyroid arteries. It supplies all the intrinsic muscles of the larynx. Damage or division causes paralysis of the vocal cords on that side. THE ENDOCRINE SYSTEM1 49 (a) Thyrohyoid Hyoid bone Fibromuscuiar cord connecting isthmus of the (levator glandulae thyroidiae) Sternohyoid Thyroid cartilage Omohyoid Sternothyroid Thyroid gland Thyroid cartilage (b) Superior thyroid vein Superior thyroid artery Common carotid artery Internal jugular vein Pyramidal lobe Cricothyroid cartilage+ muscle Middle thyroid vein Thyroid gland Recurrent laryngeal nerve Inferior thyroid vein (c) Superior Thyroid cartilage laryngeal nerve Superior parathyroid Thyroid gland Inferior thyroid artery Inferior parathyroid Ligament of Berry Recurrent laryngeal nerve Fig. 3.2. Structure of the thyroid gland. a) The infrahyoid muscles related to the thyroid. The sternohyoid muscle has been removed on the right-hand side. From Textbook of Anatomy, (ed. A. W. Rogers), 1992. Reproduced with permission from Churchill Livingstone CHAPTER 3 Anatomy for surgeons 50 Parathyroid glands These paired reddish-brown glands, each about the size of a small pea, l ie behind the upper and lower aspects of the thyroid lobes. They are derived from the third (lower gland) and fourth pharyngeal (upper gland) pouches and lie within the pretracheal f ascia often within the thyroid itself. Occasionally there may be more than four. (cid:142)( cid:3) Superior glands. Each is fairly constant in position, lying behind the upper third o f the lobe inside the pretracheal fascia lateral to the trachea. Occasionally each may be m ore anterior and liable to injury during subtotal thyroidectomy. (cid:142)(cid:3) Inferior glands. Their position is more variable. They are usually found b ehind the lower part of each lobe either above or below the inferior thyroid artery as it e nters the substance of the gland. Unusual positions include retro-oesophageal, either in the neck or posterior mediastinum or the anterior mediastinum in relation to the thymus gland.