Postoperative complications - Perioperative care

Postoperative complications

Postoperative complications may occur at any time post-surgery and include general surgical complications (bleeding, infection, deep vein thrombosis), those specific to the procedure (anastomotic leaks, fistulae, adhesions, wound dehiscence) and complications secondary to coexisting disease (ischaemic heart disease, chronic obstructive airways disease, diabetes mellitus).

Immediate complications arise during the first post-operative day:

·        Haemorrhage: Primary haemorrhage refers to continuation of bleeding from surgery. It requires aggressive management and may necessitate return to theatre. Reactive haemorrhage occurs from small vessels, which only begin to bleed as the blood pressure rises postoperatively. Blood replacement may be required and in severe cases the patient may need to return to theatre.

·        Myocardial infarction is a significant risk in patients with ischaemic heart disease. Surgery may contraindicate the use of thrombolytic agents.

·        A low-grade pyrexia is normal in the immediate post-operative period but may also arise due to infection, collections or deep vein thrombosis.

·        Low urine output may occur as a result of volume depletion, renal failure, poor cardiac output or urinary obstruction. The patient may require urinary catheterisation (or flushing of the catheter if already in situ) and a clinical assessment of cardiovascular status including heart rate, blood pressure (including assessment of postural drop), inspection of the JVP, evidence of pulmonary oedema and where needed CVP measurement.

Early postoperative complications occur in the subsequent days.

·        Deep vein thrombosis and risk of thromboembolism. High-risk patients should receive prophylaxis. Patients may present with painful swelling of the legs, low-grade pyrexia or with signs and symptoms of a pulmonary embolism.

·        Confusion due to hypoxia, metabolic disturbance, infection, drugs, or withdrawal syndromes.

·        General infections include pneumonia secondary to pooling of secretions, urinary tract infections and cannula site infections.

·        Surgical site complications include paralytic ileus, anastomotic leaks, surgical site infections (with secondary haemorrhage as a result of the infection), fistula formation and wound dehiscence (total wound breakdown). Intestinal fistulae may be managed conservatively with skin protection, replacement of fluid and electrolytes and parenteral nutrition. If such conservative therapy fails the fistula may be closed surgically.

·        Postoperative hypoxia is almost always initially due to perioperative atelectasis unless a respiratory infection was present preoperatively. Prophylaxis and treatment involves adequate analgesia, physiotherapy and humidification of administered gases. Respiratory failure may occur secondary to airway obstruction. Laryngeal spasm/oedema may occur in epiglottitis or following traumatic intubation. Tracheal compression may complicate operations in the head and neck. In the absence of obstruction hypoxia may result from drugs causing respiratory depression, infection, pulmonary embolism or exacerbation of pre-existing respiratory disease. Respiratory support may be necessary.

·        Acute renal failure may result from inadequate perfusion, drugs, or pre-existing renal or liver disease. Once hypovolaemia has been corrected any remaining renal impairment requires specialist renal support.

·        Prolonged immobility increases the risk of pressure sores especially in patients with diabetes or vascular insufficiency. Skin care, hygiene, turning of the patient and the use of specialised mattresses should prevent pressure sores. Treatment involves debridement, treatment of any infection, application of zinc paste and in

·        severe cases, plastic surgery.

Late postoperative complications, which may occur weeks or years after surgery, include adhesions, strictures and incisional hernias.