The medicolegal challenges of post-operative care in the Intensive Care Unit (ICU)

Many patients develop complications due to the physiological and inflammatory changes associated with surgery. Postoperative complications are one of the leading causes of patient mortality, leading to over 3 million deaths each year. Therefore, measures to prevent, identify and treat potentially fatal complications arising during the postoperative period are vital. Consequently, admission of high-risk surgical patients to the intensive care unit (ICU) is often regarded as essential to minimise the risk of mortality. Around 10% of patients are at a higher risk of experiencing complications but identifying those who would benefit from admission to the ICU remains a challenge.

For low-risk surgical patients, admission to the ICU makes little difference to the already low mortality rates experienced by this group. Instead, monitoring systems outside the ICU, coupled with rapid response teams, may be sufficient to identify complications, some of which will be related to the patient’s comorbidities, such as heart failure, diabetes and chronic obstructive pulmonary disease, rather than the surgery itself and so may be more predictable. For patients undergoing high-risk operations, more precise management of fluid administration, haemodynamic balance, bleeding and coagulation control and pain management may be required, along with early detection of infection and prevention of venous thromboembolism and postoperative respiratory failure.

Enhanced Recovery After Surgery is a multimodal approach in which postoperative measures aim to reduce and proactively treat the response to surgical stress and speed patient recovery. The four key elements of this approach are comprehensive preoperative evaluation of the patient, optimum anaesthesia and minimally invasive surgery with the aim of reducing patient response to surgical stress, adequate postoperative management of symptoms such as pain to allow early mobilisation, and prompt reintroduction of an adequate diet.

Postoperative monitoring of vital signs should be carried out in all patients, but for those with cardiovascular or respiratory comorbidities, the use of semi-invasive monitoring including pulse wave analysis, variations in systolic volume, transthoracic bioimpedance or oesophageal Doppler ultrasound may be considered. Adequate pain relief is essential for early mobilisation but can be difficult to monitor in patients who are not able to communicate.

When body tissues are injured, they release catabolic hormones and inflammatory mediators that encourage salt and water retention so that circulating volume, blood pressure and vasoconstriction are all maintained. Therefore, patient fluid balance should be adequately preserved. Failure to do so can result in postoperative complications and an extended hospital stay. Although it is recognised that a moderately liberal fluid intake is safer than a restrictive regimen, the amount required by each patient varies according to the type of surgery, blood loss and comorbidities. Initially, the aim should be to replace lost fluids and achieve a normal circulating volume. This is followed by a maintenance period wherein fluid therapy is lowered once the patient resumes normal oral intake.

Infections are one of the commonest postoperative complications, affecting between 1% and 26% of patients. They may be superficial, affecting just the skin and subcutaneous tissue surrounding the surgical incision, or deeper, involving the fascia and muscle layers. Deep-seated infections can be difficult to treat and may require repeat surgery and a prolonged hospital stay. They can also lead to the death of the patient.

Venous thromboembolism (VTE) is a frequent and serious complication experienced by around 25% of patients after surgery. Pulmonary thromboembolism (PE) is much less common, occurring in around 1.6% of patients. Based on clinical factors, patients can be categorised according to their risk of VTE/PE but prophylactic measures are sometimes withheld due to a fear of excessive bleeding. Compression stockings are a safe and effective preventive measure together with automatic calf compression devices, and the risk of VTE is also reduced by administration of low molecular weight heparin and fondaparinux.

Around 5% of patients undergoing non-cardiac surgery will suffer a myocardial infarction, with around three-quarters of these occurring in the first 48 hours after surgery. Many affected patients do not show clinical signs. Therefore, for patients at high risk, or who have a history of cardiovascular events, monitoring of troponin levels may be indicated. Acute ischaemic events (heart attack) may lead to heart failure, which may also be caused by inadequate fluid management, acute kidney or lung injury, or sepsis. Atrial fibrillation is also relatively common post-surgery and again, many patients are asymptomatic. It may be caused by tissue trauma and pain-related catecholamine release, hypoxia or electrolyte disturbance.

Delirium occurs in over one-third of patients admitted to the ICU after surgery, although it is often underdiagnosed, so the incidence may be considerably higher. The presence of delirium is known to increase risk of mortality and the need for re-admission to hospital, and lengthens hospital stay. It also increases the likelihood of the patient developing post-intensive care syndrome (PICS), a constellation of physical, psychological and cognitive disorders that affect daily functioning and quality of life in survivors of critical illness. Patients with PICS experience loss of muscle mass and function, persistent pain, fatigue and sleep disorders, anxiety, depression and post-traumatic stress symptoms, and impaired memory, executive function and mental processing. PICS is extremely heterogeneous, and the exact symptoms, and their intensity and duration, varies from patient to patient. As the risk of PICS can be mitigated by following the approach outlined in Enhanced Recovery After Surgery regimen, this should always be adopted.