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Complications of Surgery


Introduction

Any operation, major trauma or other surgical admission may be attended by complications, many of which are potentially preventable. Some complications are somewhat inherent to the condition being treated (e.g., deep venous thrombosis [DVT] following lower limb fractures) or arise from a comorbid (pre-existing) condition, such as myocardial ischaemia, whilst others can be attributed to human or system error. Poor communication between hospital staff is a frequent cause of avoidable complications, including incomplete or inaccurate record keeping, failure to register allergies, and inadequate patient handover between colleagues.

A large proportion of complications can be prevented or minimised by anticipation, by taking prophylactic measures, by attention to detail and by early recognition and treatment of problems as they develop. In addition, most hospitals now have standard mechanisms designed to minimise system error, such as the World Health Organization (WHO) Surgical Safety checklists, now completed for all operations and involving all members of the operating team.

With potentially serious complications (e.g., bowel anastomotic leak), early diagnosis and reoperation is crucial, as delay often leads to catastrophic ‘snowballing’ sepsis and multiorgan failure. Once two or more body systems become impaired, survival falls to only about 50%. If, for example, acute respiratory distress syndrome (ARDS) and acute kidney failure complicate an operation for obstructive jaundice in a patient with liver impairment, the odds are heavily stacked against survival.

In operative surgery, complications can be considered as those that can befall any operation or specific complications of individual operations. Both groups can be subdivided into immediate (during operation or within the next 24 hours), early postoperative (during the first postoperative week or so), late postoperative (up to 30 days after operation) and long term .

Surgical complications fall into the five broad categories listed in Box 12.1 . ‘Medical’ complications are discussed in Chapter 8 . Complications of specific operations are discussed in Chapter 18, Chapter 19, Chapter 20, Chapter 21, Chapter 22, Chapter 23, Chapter 24, Chapter 25, Chapter 26, Chapter 27, Chapter 28, Chapter 29, Chapter 30, Chapter 31, Chapter 32, Chapter 33, Chapter 34, Chapter 35, Chapter 36, Chapter 37, Chapter 38, Chapter 39, Chapter 40, Chapter 41, Chapter 42, Chapter 43, Chapter 44, Chapter 45, Chapter 46, Chapter 47, Chapter 48, Chapter 49, Chapter 50, Chapter 51 , as appropriate.

BOX 12.1
Principal Categories of Surgical Complications

  • 1.

    Complications predisposed to by comorbid ‘medical’ disorders, whether symptomatic or occult, for example, ischaemic heart disease, chronic respiratory disease or diabetes mellitus (see Ch. 8 )

  • 2.

    Complications of anaesthesia

  • 3.

    General complications of operations, for example, haemorrhage or wound infection

  • 4.

    Complications of any surgical condition, for example, pulmonary embolism, pneumonia or urinary tract infection

  • 5.

    Complications of specific disorders and operations

Complications of Anaesthesia

The main complications of anaesthesia are summarised in Box 12.2 .

BOX 12.2
Complications of Anaesthesia

Local Anaesthesia

  • Injection site—pain; haematoma; delayed recovery of sensation (direct nerve trauma); infection

  • Vasoconstrictors—ischaemic necrosis (if used in digits or penis)

  • Systemic effects of local anaesthetic agent

    • Toxicity caused by excess dosage (see Ch. 10 , p. 124) or inadvertent intravenous injection. Same effect produced by premature release of a Bier’s block cuff

    • Toxic effects include: dizziness, tinnitus, nausea and vomiting, fits, central nervous system depression, and cardiac dysrhythmias including bradycardia and asystole

    • Idiosyncratic or allergic reactions (very rare)

Spinal, Epidural and Caudal Anaesthesia

  • Failure of anaesthetic—anatomical difficulties or technical failure

  • Headache after operation—loss of cerebrospinal fluid because of dural puncture

  • Epidural or intrathecal bleeding—increased risk if patient on anticoagulants

  • Unintentionally wide field of anaesthesia

    • In epidural anaesthesia, injection into wrong tissue plane may give a spinal anaesthetic

    • In spinal anaesthesia, respiratory paralysis occurs if the anaesthetic agent flows too far proximally

  • Permanent nerve or spinal cord damage—injection of incorrect or contaminated drug

  • Paraspinal infection—introduced by the injection

  • Systemic complications—autonomic block may cause severe hypotension or postural hypotension

General Anaesthesia

Postoperative Nausea and Vomiting

  • Usually a response to anaesthetic or analgesic drugs. Individual sensitivity varies. Antiemetics usually administered before end of anaesthesia

Pain

  • Analgesics usually administered during operation (e.g., intravenous opiates or paracetamol, diclofenac suppositories) plus local/regional anaesthetic techniques

Problems With Drugs and Fluids

  • Fluid and electrolyte imbalance—too little, too much or inappropriate intravenous infusion

  • Inappropriate choice of drugs or dosage in relation to age or the requirements of day surgery

  • Idiosyncratic or allergic reactions to anaesthetic agents

    • Minor effects, for example, nausea and vomiting

    • Major effects, for example, cardiovascular collapse, respiratory depression, halothane jaundice

  • Unexpected drug interactions—a wide range of adverse effects may occur

  • Inherited disorders

    • Malignant hyperpyrexia (MH): any inhalational anaesthetic or suxamethonium may trigger MH

    • Pseudocholinesterase deficiency produces prolonged apnoea after succinylcholine

  • Slow recovery from anaesthetic—many reasons including inadequate reversal

  • ‘Awareness’ during anaesthetic—effective paralysis but ineffective anaesthesia

Cardiovascular Complications

  • Myocardial ischaemia/infarction/failure, arrhythmias, hypo/hypertension, tachy/bradycardias

Respiratory Complications

  • Laryngospasm/bronchospasm, atelectasis, upper or lower respiratory tract infections

Renal Complications

  • Particularly in patients with comorbid renal impairment—prerenal, renal or postrenal

Hypothermia (Note: Neonates and Small Infants Are Especially Vulnerable to Hypothermia)

  • Long operations with extensive fluid loss

  • Large-volume transfusion of cold blood

Inadvertent Trauma

  • Dental problems and prostheses

    • Teeth (particularly decayed or loose), crowns and bridges are vulnerable during intubation. Damage risks aspirating a foreign body into a bronchus and causes cosmetic and medicolegal problems.

    • Infected material from carious (decayed) teeth or inflamed gums may be aspirated and cause a particularly grave aspiration pneumonia.

    • Dentures must be removed before operation and labelled. Unconscious accident victims may aspirate or swallow a dental prosthesis or obstruct the pharynx with it.

  • Corneal abrasions

  • Pressure injury to nerves (especially ulnar, radial and lateral popliteal)

  • Diathermy pad burns

  • Initiation of pressure sores

General Complications of Operations

The main complications of any operation are: inadvertent trauma to the patient in the operating department, haemorrhage, surgical damage to related structures, inadequate operation, surgical site infection and problems with wound healing.

Inadvertent Trauma in the Operating Department

Patients are at risk of injury during transport or transfer in the operating department, especially when under anaesthesia. Staff involved in handling patients are also at risk of injury, for example to the back. The WHO Surgical Safety Checklist incorporates team recognition of artificial joints, presence of devices such as pacemakers, implanted metalwork from previous operations and any other transfer concerns, to warn of the need for extra vigilance during patient positioning and during the procedure.

The most common causes of trauma in the operating theatre are:

  • Injuries resulting from falls from trolleys or from the operating table during positioning.

  • Injury to diseased bones and joints from manipulation or positioning. These include dislocation of rheumatoid atlantoaxial joints and dislocation of a prosthetic hip or other joint.

  • Ulnar, lateral popliteal and other nerve palsies resulting from pressure.

  • Electrical burns from wet or poorly contacting diathermy pads or misuse of the diathermy probe.

  • Excess pressure on the calves causing DVT.

  • Excess or prolonged heel pressure causing pressure sores.

  • Cardiac pacemaker disruption by diathermy equipment—minimised by using bipolar diathermy wherever possible. Pacemaker checks are performed pre- and postprocedure if needed but modern pacemakers are much more resistant to electrical interference.

Haemorrhage

Perioperative Haemorrhage

Haemorrhage occurring during an operation ( primary haemorrhage ) should be controlled by the surgeon before the operation is completed.

Early Postoperative Haemorrhage

Haemorrhage immediately after operation usually indicates inadequate operative haemostasis or a technical mishap, such as a slipped ligature or unrecognised blood vessel trauma. Occasionally, it is caused by a bleeding disorder.

If an operation involves major blood loss and large volume transfusion of stored blood, haemorrhage may be perpetuated by consumption coagulopathy , in which platelets and coagulation factors have been ‘consumed’ in a vain attempt at haemostasis. Disseminated intravascular coagulopathy (DIC) can be one facet of the systemic inflammatory response syndrome ∗

∗ The definitions for systemic inflammatory response syndrome (or SIRS) has recently changed. Clinicians are encouraged to use ‘Sepsis-3’ and the Sequential Organ Failure Assessment (SOFA) score.

with widespread intravascular thrombosis and exhaustion of clotting factors. Any patient giving a history of excess bleeding should have a platelet count and coagulation screen checked before operation.

Operations at particular risk of early postoperative haemorrhage include:

  • major operations involving highly vascular tissues, such as the liver or spleen;

  • major arterial surgery, especially ruptured aortic aneurysm (large volume blood loss may occur, and the patient may be heparinised during operation);

  • operations which leave a large raw surface, such as abdominoperineal excision of rectum.

This type of postoperative haemorrhage has been traditionally described as reactionary in the belief that it was a ‘reaction’ to the recovery of normal blood pressure and cardiac output. This concept is probably misleading and should now be discarded, especially since it may hinder the decision to reoperate urgently.

Management of Early Postoperative Haemorrhage

This is really a form of primary haemorrhage and, if substantial, the patient must be surgically reexplored and the source treated. It is wise to perform a clotting screen (including platelet count) and order bank blood as a preliminary measure. Good intravenous access should be ensured. If heparin was used at the original operation, protamine can reverse any residual activity. If the clotting screen is abnormal, infusions containing clotting factors may be needed, as advised by a haematologist. Many patients will stop bleeding with supportive measures and blood transfusion but reexploration must be seriously considered at every stage.

Later Postoperative Haemorrhage

Haemorrhage occurring several days after operation is usually caused by infection eroding blood vessels near the operation site. This is known as secondary haemorrhage . Treatment involves managing the infection, but exploratory operation is often required to ligate or suture the bleeding vessels.

Anticoagulant and Antiplatelet Therapy Considerations in Surgery

Several different anticoagulant and antiplatelet therapies exist (i.e., warfarin, clopidogrel, dabigatran, rivaroxaban, apixaban, edoxaban). These are designed to prevent intravascular thrombosis and have a lesser effect on surgically induced bleeding. All should generally be stopped preoperatively for their respective advised durations (i.e., stop warfarin 5 days before surgery; stop clopidogrel 7 to 10 days before surgery) to minimise complications with peri- and postoperative bleeding. Patients at higher risk of thromboembolism or other related complications from stopping their anticoagulant must have bridging treatment with an alternative short-acting preparation, under advice from their medical team or haematologist. An example is a subcutaneous low-molecular-weight heparin (LMWH), such as dalteparin, given once the anticoagulant is deemed to be at a subtherapeutic level (i.e., international normalised ratio [INR] falls below the target range in patients treated with warfarin), and is then stopped 24 hours before surgery. Remember to resume the patient’s normal anticoagulation therapy postoperatively if there is no active bleeding, and continue bridging therapy in those needing it until their normal anticoagulation medication is therapeutic again (e.g., INR is back in range). It is no longer considered necessary to stop low-dose aspirin before surgery.

Surgical Injury

Unavoidable Tissue Damage

Anatomical structures, particularly nerves, blood vessels and lymphatics, may be unavoidably damaged during operation. This is particularly true in cancer surgery, illustrated by facial nerve excision during total parotidectomy. If anticipated, the probability must be discussed with the patient beforehand as part of the documented informed consent process. Sometimes, the integrity or location of vulnerable structures can be established before operation, allowing better planning of the operation. For example, indirect laryngoscopy may be done to assess vocal cord integrity before thyroid surgery.

Inadvertent Tissue Damage

Structures may be inadvertently damaged during operation. Examples include recurrent laryngeal nerve damage during thyroidectomy, or trauma to bile ducts during cholecystectomy. The main factors are inexperience, anatomical anomalies, attempts at arresting precipitate haemorrhage and tissue planes obscured by inflammation or malignancy. Signs of damage to structures at particular risk should be sought in the postoperative period; for example, hoarseness after thyroidectomy or jaundice after cholecystectomy.

Infection Related to the Operation Site

Minor Wound Infections

The most common infective complication is a superficial wound infection (surgical site infection) within the first postoperative week. This relatively trivial infection presents as localised pain, redness and a slight discharge. Organisms are usually staphylococci derived from skin and the infection usually settles spontaneously, or after a short course of oral antibiotics. In patients with recent prosthesis insertion, such as an arterial graft or artificial joint, any sign of infection must be treated aggressively with antibiotics to prevent infection of the prosthesis which is likely to be disastrous.

Wound Cellulitis and Abscess

More severe wound infections occur most often after bowel-related surgery, when staphylococci (methicillin-sensitive or resistant varieties) or faecal organisms are usually incriminated. Most appear in the first postoperative week but they may occur as late as the third week, sometimes after leaving hospital. These infections commonly present with pyrexia, and wound examination reveals spreading cellulitis ( Fig. 12.1 ) or localised abscess formation .

Fig. 12.1, Abdominal Cellulitis.

Cellulitis is treated with antibiotics after taking a wound swab for culture and sensitivity, whereas a wound abscess is treated by surgical drainage. This may simply involve suture removal and wound probing, but deeper abscesses may need reexploration under general anaesthesia. In either case, and for smaller defects, the wound is left open afterwards to heal by secondary intention ( Fig. 12.2 ). Alternatively, for larger defects, the application of a vacuum dressing ( negative-pressure wound therapy ) by a tissue viability team can accelerate wound healing. This involves application of a foam pad covered by an occlusive dressing connected to a vacuum pump which continuously draws out fluid and encourages blood flow to the affected area.

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