A clerking consists of the history of the presenting complaint, past medical history, drug history, family history and social history. You should then examine the patient fully, looking first at their general health and whether they are fit enough for the operation, and if not you should be thinking of ways to optimise their health, such as using preoperative nebulisers for an asthmatic. The clerking also allows other problems to be picked up.
If, when the patient arrives on the ward, you feel that the diagnosis made in the out-patient clinic has changed, you should inform a senior colleague before the operation is booked. For example, if a patient was admitted for an excisional biopsy of a lymph node that has completely disappeared when you examine them, you should inform your consultant, as the operation might need to be cancelled.
In the main, appropriate investigations should be performed before surgery and this is often a good question for a viva examination. For example, before a laparascopic cholecystectomy is performed the patient should have had an ultrasound to confirm the presence of gallstones, and a set of liver function tests. The house officer should discuss the order of patients on the operating list with the operating surgeon. Usually, children are placed first on the list, as this is nicer for the child and the parents; also they find it hard to go without food for long periods. If special equipment is needed in the theatre, such as the image intensifier for X-rays or laparascopic equipment, then these should be discussed with the theatre staff (and radiographers) the day before.
Specialist nurses who have expertise in certain areas such as breast disease, wound management and stomas should be involved preoperatively in all appropriate cases. For example, a patient who is likely to need a colostomy or ileostomy should be seen by the stoma nurse specialist several days before the operation. This allows for patient education (i.e. answering of any questions and worries), and also the site where the stoma will be cited is marked (note that the patient should be standing, so
as to position it in the most appropriate place).
Many patients have problems other than the one that is being operated upon. These may be social and as such need a social work or occupational therapy referral. For example, if the patient has difficulty climbing stairs and there is no lift, then there may be a need to arrange for a stair lift or rehouse into ground floor accommodation.
The patients may have intercurrent medical problems such as diabetes, hypertension or chronic obstructive pulmonary disease (COPD). They may also be on drugs such as steroids or anticoagulants. When clerking the patient you should be looking out for these, and if you think they may affect the operation, then you should inform the anaesthetist or the consultant in charge of the patient.
As a house officer the tests you need to consider preoperatively include blood tests, such as a full blood count, a sickle screen if at risk (this includes anyone of Afro-Caribbean origin), and either a group and save or a cross-match. You should X-match any patient at risk of blood loss extensive enough to need replacing — for example, the anticipated blood loss from an anterior resection is about two units, but to be safe we usually X-match four units. The blood is kept in the refrigerator ready for use. If it is not used it goes back to the blood bank for storage.
A young healthy person, in general, requires no preoperative investigations, but if at all unsure then you should ask the anaesthetist what they would like performed (for example, some anaesthetists like to have a recent full blood count on all females of childbearing age). The National Institute for Clinical Excellence (NICE) have issued guidelines on preoperative
investigation available here. If the patient is hypertensive or on diuretics then a U & E (urea, creatinine and electrolytes) to assess renal function must be performed. An ECG is necessary on anyone who is hypertensive or has a history of heart disease, and a chest X-ray on anyone
with respiratory disease, including a personal or family history of TB.
In most hospitals the requirement is to order an ECG and CXR as a baseline on the elderly (aged over 60), but check the policy in your hospital. The management of medical problems in surgical patients is essentially the same as that you read about in medical textbooks. We will, however,
cover just a few topics.
Diabetics have an increased incidence of perioperative complications. The stress of surgery can lead to an increased production of catabolic hormones, such as glucagon and catecholamines, which antagonize the action of insulin, making control more difficult, especially as the patient will also be nil by mouth. These patients are at an increased risk of infection (wound, chest, IV access sites and urine), peripheral vascular disease, pressure sores and ischaemic heart disease. The aim is to maintain the patient’s blood sugar level between 5 and 9 mmol/l. Preoperatively you should dipstick the urine to check for protein, send off a laboratory blood
glucose, check the electrolytes and creatinine and order an ECG.
Management depends on the types of diabetes.
For anything other than minor surgery it is probably best to put these patients on an insulin sliding scale to establish good control. This means they are on a drip of dextrose or dextrose saline (as they are not eating), together with a continuous infusion of fast-acting insulin (‘Actrpid’). The rate of infusion of insulin will depend on their blood sugar level, which can be monitored by hourly BM stix (a finger prick testing stick specific for glucose). If the BM is low the infusion is decreased or stopped, and if the BM is high the insulin rate can be increased to bring the sugar level down. It is important that you add potassium to each bag of fluids you give, since the insulin causes cellular uptake of potassium and can lead to hypokalaemia. The sliding scales regimen differs in different hospitals and
you should try and get hold of a sliding scale protocol at your hospital.
This is one example:
Diabetics Controlled with Oral Hypoglycaemics
Long-acting oral hypoglycaemics such as metformin should be changed to a short-acting sulphonylurea (e.g. Gliclazide) a few days before the operation. Ask the diabetic team for advice. On the morning of the operation omit the dose of oral hypoglycaemic. This can be resumed once the patient starts eating postoperatively. The BMs should be measured, and if very high the blood sugar can be brought down by small doses of subcutaneous soluble insulin (e.g. 6 units of actrapid). If this fails to control the sugar level or in the case of major surgery, you cannot go wrong by simply converting the treatment to a sliding scale as above. Diabetics should really go first on the list, as the starting time is predictable and this allows better management of sugar levels.
Diabetics Controlled by Diet Alone
These patients rarely need any special measures. Remember that provided they have not been given any insulin or oral hypoglycaemics the patients cannot become hypoglycaemic (unless they have an insulinoma); if anything, their sugar level will be high. A BM stix will tell you where you stand if you are worried. If you find their control is poor, then you should refer the patients back to their diabetologist.
Patients on steroids are liable to impaired healing and postoperative infections. Also, long-term corticosteroids can lead to adrenal insufficiency, where the adrenals are unable secrete the increased glucocorticoids necessary in response to the stresses of surgery. This can lead to an Addisonian crisis, where the patient becomes shocked. Patients who have been on long-term oral steroids should therefore be treated with perioperative steroids. This usually means intravenous hydrocortisone before and after the operation until the patient can resume their oral intake.
CHRONIC OBSTRUCTIVE PULMONARY DISEASE
Surgery and anaesthesia predispose patients to basal lung collapse (atelectasis),
aspiration pneumonitis and chest infection. This is especially true of operations on the abdomen, since the patient may be in pain and therefore does not cough up the secretions. Any pre-existing respiratory disease, such as chronic obstructive pulmonary disease (COPD), increases the risk of chest complications, as do smoking, obesity and old age. Preoperatively, therefore, you should arrange for a chest X-ray and lung function tests in any patient with pre-existing chronic airways disease.
You should also do a baseline blood gas analysis if hypoxia or carbon dioxide retention is anticipated. You can assess the degree of reversibility of the airway disease by measuring peak flows before and after bronchodilators are given by nebuliser.
If there is a degree of reversibility, then prescription of nebulisers may help optimise lung function. Physiotherapy is an important modality in these patients and preoperative breathing exercises can help prevent a chest infection. Postoperatively physiotherapy should be initiated early to help remove airway secretions, especially in abdominal operations. Smokers should be encouraged to stop smoking at least 4 weeks prior to elective surgery.
DEEP VEIN THROMBOSIS
All surgical patients are at risk of deep vein thrombosis (DVT). In some hospitals prophylaxis with subcutaneous low molecular weight heparin injections and thromboembolic deterrent (TED) stockings is given to all surgical patients, whereas other hospitals only give this to patients at medium-to-high risk of DVT. Risk factors for DVT include previous thrombosis or pulmonary embolus, long periods of immobility, pelvic or hip operations, obesity, cancer and use of the oral contraceptive pill. Find out what the DVT prophylaxis protocol is in your hospital.
Intermittent limb compression is where an inflatable device is wrapped around the legs and periodically blown up, from the distal to the proximal end, encouraging venous return. Also available is low molecular weight (LMW) heparin, which is thought to work on the antiplatelet factor antithrombin III and therefore has little effect on the intrinsic clotting cascade.
In normal prophylactic doses LMW heparin does not require monitoring; it is longer acting and thus only needs to be given once daily. LMW heparin is as effective as unfractionated heparins. Newer drugs such as direct thrombin inhibitors are also now available.
In most cases, early mobilisation in combination with one or more of the above options is acceptable.
Antibiotic cover is necessary for surgery if there is an increased risk of infection. This could be due to patient-related factors or those related to
the type of operation. Contaminated operations, such as those where the bowel contents can leak out, carry a high risk of infection, as do operations where a prosthetic implant is used (e.g. joint replacement), and antibiotics should always be given in these cases.
An example of a patient-related factor is mitral valve disease and the subsequent risk of developing endocarditis. We usually give prophylactic antibiotics intravenously at induction of anaesthesia, so that blood levels are high during the operation, followed by two subsequent doses postoperatively (usually after about 8 and 16 h).
If a tourniquet is being used, then the antibiotics must be given before the
tourniquet is inflated. You should have a rough idea of which organisms are likely to be responsible for the infection and which antibiotics should therefore be
used. A common question concerns methicillin-resistant Staphylococcus aureus (MRSA), which is an increasing problem in many hospitals. It is especially worrying when it infects patients with prosthetic implants such as hip replacements or vascular bypasses.
Operations Involving the Bowel
Mainly Gram-negative bacilli, i.e. coliforms, but also faecal anaerobes (bacteroides) and S. aureus from the skin. In the gut there is also Enterococcus faecalis (also known as strep faecalis), but this causes infection less commonly. In bile, the majority of infections are with gut bacteria, such as Escherichia coli, and, rarely, pseudomonas, which is more difficult to treat.
We tend to use a cephalosporin to cover the Gram-negative organisms together with metronidazole to cover anaerobes. If you are concerned about strep faecalis you should add amoxycillin, as the cephalosporins do not cover this well. For operations on the biliary tree, such as a laparascopic cholecystectomy, you could either use the same regimen as above or just use a cephalosporin alone, as most infections are with Gram-negative bacilli (mainly E. coli). One dose at induction is sufficient. For improved biliary penetration such as before and after an ERCP or for ascending cholangitis, a broad-spectrum B-lactam such as pipericillin is often used. This also covers for pseudomonas.
Operations Involving Prosthetic Implants
Skin organisms are usually responsible. S. aureus is the commonest pathogen, but also S. epidermidis tends to colonise the newer plastic prostheses. Rarely, coliforms are responsible.
Either a broad-spectrum cephalosporin or flucloxacillin. Orthopaedic operations involving metalwork require a dose of intravenous antibiotics (usually a cephalosporin) at induction and for about 24 h postoperatively. Similarly, valve replacements are usually given amoxycillin (or a cephalosporin) and gentamycin. If MRSA is a particular worry, then vancomycin may be used.The British National Formulary contains up-to-date advice on this topic. Remember that if ischaemic or necrotic tissue is involved, then spores of clostridium tetani may cause gas gangrene. Benzylpenicillin, to which the organism is highly susceptible, is the prophylaxis (and treatment) of choice against this (this includes penetrating wounds and compound fractures).
The mnemonic “ABCD LMNOPs” is helpful in remembering preoperative management:
A — Antibiotics/anaesthetist
B — Bloods (including X-match)/bowel preparation
C — Consent/CXR
D — Drug chart/DVT prophylaxis
E — ECG
F — Fluids (especially if NBM or if the patient is vomiting)
L — List (put in the theatre list)/lung function tests
M — Mark the area or limb (should be done by the operating surgeon)
N — Notes should be filed correctly
O — Operating theatre staff (e.g. book special equipment/radiology)
P — Physiotherapy
S — Specialist nurses (e.g. breast care or stoma care nurses)