11.1 Introduction

Common postoperative problems occur despite the best of surgical care but can be minimised with adequate preoperative planning. Patient-related concurrent medical problems are identified prior to surgery and these conditions are optimised. This has been discussed in detail in chapter 10.

Postoperative care starts before the patient is taken to operating theatre. For example, cessation of smoking at least one week prior to surgery is beneficial. Attention to symptoms and signs in the early postoperative period may detect small but vital changes and proper management could prevent further deterioration and hence avoid major complications. For example, inadequate pain relief in a patient who has abdominal surgery would lead to poor respiratory efforts with atelectasia, especially in a smoker. Good pain relief, and chest physiotherapy that can be learnt preoperatively, and early mobilisation can potentially prevent this and avoid the onset of pneumonia.

Pain starts from the time of surgery. Inadequate pain relief can potentially exacerbate other problems and this will be addressed during surgery (pre-emptive analgesia such as local anaesthetic infiltration of the wound) and provided for adequate immediately on completion of surgery.

Good postoperative care requires precise and comprehensive orders on completion of surgery. Instructions should include not just observable vital signs such as heart rate, blood pressure, respiratory rate, oxygen saturation and urine output. They should include the care of wounds and drains. Daily inspection of intravenous line, drain, urinary catheter and wound can detect problems before the onset of established sepsis. Fever is often the first sign pointing to a brewing problem.

A few days following surgery, thromboembolism, secondary haemorrhage or cardiac compromise can lead to sudden deterioration or collapse.

The most common postoperative problems are listed in Table 11.1.

Table 11.1 Postoperative complications

Wound	Infection
	Haematoma
	Dehiscence
	Incisional hernia
Fever	Atelectasis
	Sepsis
	Thromboembolic disease
Vomiting	Anaesthesia
	Ileus
	Obstruction
Shock	Haemorrhage
	Myocardial infarction
	Sepsis
	Pulmonary embolus
Haemorrhage	Wound
	Concealed
	Gastrointestinal
	Secondary
Jaundice	Septicaemia
	Drug cholestasis
	Hepatitis
Respiratory	Atelectasis
	Aspiration
	Adult respiratory distress syndrome
	Pneumothorax
Cardiovascular	Arrhythmias
	Myocardial infarction
	Congestive cardiac failure
Urinary	Retention
	Infection
	Renal injury
Psychiatric	Delirium
Vascular access	Phlebitis
	Pneumothorax

11.2 Pain

Planning is important in the control of postoperative pain. This starts before surgery and, depending on the amount of anticipated pain, the patient is counselled as to what to expect following surgery and the methods of pain relief.

Different surgeries produce varying amounts of pain. The size and site of the wound affect the amount of pain. Skin graft donor site, vertical upper abdominal, chest, hand and loin incisions typically require more analgesia. The cultural, age and emotional status of the patient may affect the amount of postoperative pain.

Effective pain relief reduces the metabolic stress response to surgery. This reduces the cardiac demand, improves respiratory effort and lessens sputum retention, atelectasis and pneumonia and promotes mobility. The end result is earlier discharge and fewer complications.

Pre-emptive analgesia is started at operation. This includes:

• oral or rectal or intravenous nonsteroidal anti-inflammatory drugs (NSAIDs) given before or during surgery (NSAIDs are contraindicated in patients with renal impairment, known allergy, severe asthma, bleeding disorders, hypovolaemia and pregnancy)

• oral or intravenous paracetamol with or without codeine and tramadol, which is effective in those with anticipated mild to moderate pain

• local anaesthetic infiltration into the wound edge or field and ring block at the start of operation with long-acting bupivacaine (this is the most common approach although a specially designed catheter can be left in the wound at the completion of surgery to allow a continuous infusion of the anaesthetic agent)

• regional nerve blocks such as brachial plexus or femoral nerve blocks for upper or lower limb surgery

• spinal or epidural analgesia for abdominal or pelvic surgery.

The role of pain relief after major surgery is often undertaken by the acute pain service as a continuation of the anaesthetic care. A multimodality approach is used to achieve the best results.

Intermittent intramuscular opiates given at three- to four-hourly intervals (or as required) gives poor pain relief. Patients differ widely in the amount of analgesia required after major surgery. Opiates given intravenously as a continuous infusion are more effective, but this can result in respiratory depression if a larger than necessary dose is given. A much better and effective way to administer intravenous opiates is the patient-controlled analgesia (PCA) device. This allows the patient to control the frequency of a given dose with a lockout to prevent excessive dosage over a given period of time. This technique improves pain relief with minimal respiratory compromise.

For major operations involving the abdomen, pelvic or lower limb, epidural analgesia using opiates and local anaesthetic agent such as bupivacaine gives excellent pain relief. An epidural catheter is left in situ to allow longer term administration of agents. This method requires a dedicated team and close observation in the high-dependency unit (HDU) to avoid toxicity, severe hypotension, dense motor block and respiratory depression.

Non-opiates such as NSAIDs are effective for moderate pain. They can be given in the oral, rectal or intramuscular form. They do not cause nausea or vomiting, sedation or depression of respiratory and bowel functions. When given in combination with opiates, they reduce the requirement of opiates and hence the associated side effects. NSAIDs can cause renal impairment, gastric irritation and bleeding and bronchospasm and their use are contraindicated as mentioned.

11.3 Nausea and vomiting

Nausea and vomiting are common in the immediate postoperative recovery. These are often due to anaesthetic-related agents and postoperative analgesia, especially opiates. The common causes are listed in Box 11.1. These include: early, postanaesthetic sickness;

Box 11.1

Causes of postoperative vomiting

Anaesthetic drugs and gases

Acute gastric dilatation

Paralytic ileus

Intraperitoneal abscess

Adhesive mechanical obstruction

Strangulation of bowel

Table 11.2 Commonly used analgesics and dosage guide

acute gastric dilatation within 48 hours; paralytic ileus from two to three days; and mechanical intestinal obstruction thereafter.

Modern anaesthetic techniques and the use of antiemetics such metoclopramide, ondansetron and dexamethasone routinely in combination with opiates, have reduced the incidence of this early postoperative period. Potentially lethal aspiration may occur, especially in patients with gastrointestinal obstruction or bleeding, and in those who are extubated before the respiratory and cough reflexes have adequately recovered from anaesthesia.

Nausea and vomiting in the early and late postoperative recovery are often related to delayed gastrointestinal function. Acute gastric dilatation is nowadays a rare complication. Copious volumes are lost by effortless vomiting and there is a grave danger of pulmonary aspiration. The problem occurs mainly in the debilitated, depleted patient, with a persistent atonic defect of gastric emptying after surgery. Immediate nasogastric intubation and aspiration is warranted to prevent potential aspiration.

Paralytic ileus is much more common and is assumed to be present when gastrointestinal function has not returned within three days of surgery. The gastric and small intestinal function recovers quickly after operation. The large bowel takes longer to recover. Normal recovery of bowel function is heralded by hunger, return of bowel sounds and the passage of flatus. Ileus is more common after large bowel surgery or retroperitoneal aortic surgery. Ileus may be contributed to by operative trauma such as rough bowel handling, by electrolyte disturbance (especially hypokalaemia) and by severe systemic illness. Most cases will spontaneously resolve. Persistent vomiting and distension in the patient with ileus (with persistent X-ray signs of distended, fluid-filled small and large bowel) suggest that an intra-abdominal complication such as abscess may have occurred and this may require intervention.

A later onset of vomiting and distension, with colicky pain, in a patient who otherwise appears to be recovering satisfactorily suggests that mechanical adhesive obstruction has developed. Ileus and mechanical obstruction, however, may be very difficult to differentiate in the postoperative period. Patients with suspected adhesive obstruction are also treated conservatively initially. This consists of intermittent nasogastric aspiration and drainage, correction of fluid and electrolytes, and analgesia. But, if tenderness or a mass develop, if pain is severe or becomes continuous or if symptoms and signs persist for more than two to three days, laparotomy is indicated because of the danger of strangulation.

Ileus of the large bowel (pseudo-obstruction) can occur in a debilitated and ill patient who has severe illness other than an abdominal cause. The presentation is often vomiting, abdominal distension and pain. The treatment is colonoscopic decompression to prevent colonic rupture.

11.4 Tachycardia

Tachycardia is defined as rapid heartbeat of more than 100 beats per minute. This may be a feature of inadequate pain relief, anxiety, a cardiovascular disorder, infection or thyrotoxicosis.

Effective pain relief reduces the metabolic stress response to surgery and this reduces the cardiac demand and anxiety level of the patient. The stress response is characterised by tachycardia.

Hypovolaemia either from excessive loss, as in haemorrhage or gastrointestinal loss, or dehydration from inadequate fluid replacement is manifested by tachycardia unless the cardiac response is suppressed by beta-blockers. Treatment is rapid correction of coagulopathy, seeking the source of haemorrhage and intravascular volume replacement. A central venous line along with a urinary catheter are helpful in monitoring the progress of treatment (Ch 11.9).

Cardiovascular disorders that produce tachycardia include cardiac failure, myocardial infarction and cardiac arrhythmias such as atrial fibrillation or flutter. Medical consultation is required and appropriate therapy should be instituted.

One of the signs of severe sepsis is tachycardia with or without hypotension. In postoperative abdominal surgery, gastrointestinal anastomotic leakage must be suspected and treated appropriately.

11.5 Fever

Postoperative fever is common and often is part of the body response to trauma/surgery. The fever is mild but should be closely monitored on the daily ward round. Early diagnosis of the cause and treatment prevents its progression to a major problem.

A number of factors are helpful in determining the possible causes of fever. These include the timing of fever in relation to surgery, the pattern of temperature changes and the type of surgery with its specific complications. Table 11.3 provides a summary of the common causes of postoperative fever and Figure 11.1 provides a visual summary of the timing and pattern of fevers.

Table 11.3 Causes of postoperative fever

Diagnosis	Days after operation
Reaction to blood products	0–1
Atelectasis	1–2
Pneumonia	2–4
Infusion thrombophlebitis	2–5
Wound infection	5–30
Thromboembolism	5–15
Less common causes
Tissue necrosis — myocardial infarction	0–5
Malignant hyperpyrexia	0–5
Neoplasm	–
Acute gout	5–10
Fat embolism syndrome	2–5
Drug allergy	–
Endocrine — thyroid or adrenal crisis	2–5
Iatrogenic-overheating patient	–
Faking of fever by patient	–