- Email: [email protected]
Postoperative care
MEDICINE AND OTHER SPECIALTIES
Postoperative care
Key points
Emma Tyson
C
Enhanced recovery protocols use a combination of evidencebased elements to reduce hospital length of stay and postoperative morbidity. This improves the patient’s recovery and has financial benefits for the hospital
C
Immobility in bed leads to a loss of 1e3% muscle mass per day. The benefits of mobilization should be emphasized, and patients should be encouraged to mobilize by healthcare staff and relatives
C
Early oral intake leads to earlier return of gut function and reduces the effects of surgical stress
C
Early oral fluids reduce intravenous fluid use and can assist with the challenge of perioperative fluid management. This also encourages mobilization
C
Postoperative complications are important causes of morbidity and mortality, and lack of early assessment and intervention can lead to ‘failure to rescue’. Around 80% of inpatient postoperative deaths occur in 15% of patients who have preoperatively identifiable risk factors
Ben Creagh-Brown
Abstract Optimal postoperative care involves a multidisciplinary team of healthcare professionals and a patient-centred approach to avoid postoperative complications and enable a rapid return to normal function. During the last decade, enhanced recovery after surgery programmes have been implemented worldwide to reduce complications and length of stay e challenging traditional models of perioperative care. Some aspects of perioperative care have consensus guidelines without significant controversy, whereas others, such as perioperative fluid therapy, remain contentious.
Keywords Enhanced recovery; fluid management; myocardial injury after non-cardiac surgery; perioperative care; pulmonary complications
Introduction The aims of postoperative care are to restore physiological function, prevent complications and prevent the need for a prolonged stay in hospital. Enhanced recovery after surgery (ERAS; www.erassociety.org) is an evidence-based, multifaceted, patient-centred programme that has been shown to reduce postoperative complications and hospital length of stay. It has been adopted by many surgical specialties. ERAS programmes include pre-, intra- and postoperative elements.
neuropathic pain or chronic opioid use. Patient counselling is important to manage expectations as it is recognized that anxiety increases pain perception. Relief of pain allows patients to cough, breathe effectively and move e all of which are beneficial. Traditional postoperative opiate use has undesirable dose-related adverse effects such as nausea, constipation, vomiting, dizziness, confusion and respiratory depression. Opiates usually cause constipation, so all patients given opiates should be prescribed regular laxatives to mitigate this. Effective pain relief can also reduce the incidence of chronic pain syndromes. Inadequate pain management can lead to reduced deep breathing and limited mobility, both of which predispose to the development of postoperative pulmonary complications (PPCs).
Pain and multimodal opiate-sparing analgesia Multimodal opiate-sparing analgesia refers to the use of a variety of analgesic agents, working via different mechanisms, to minimize opiate use. They typically include acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs) and local, regional or neuraxial analgesics. Other agents include gabapentin, lidocaine, clonidine and ketamine. Patients commonly fear that they will experience pain after an operation, although severe surgical pain only affected 11% in the Sprint National Anaesthesia Project (SNAP-1) national study.1 Risk factors for severe discomfort included younger age, female sex, obesity, history of stroke or transient ischaemic attack and
Perioperative fluid management Postoperative fluid management remains a contentious and challenging issue for clinicians. The difficulty in accurately assessing hydration status, even with advanced monitoring, means that achievement of optimal balance remains elusive. Inadequate fluid administration leads to hypovolaemia, which contributes to decreased organ perfusion; this can manifest in a range of ways, including acute kidney injury (AKI). By contrast, excessive fluid administration leads to electrolyte disturbances and water overload, which causes oedema and can manifest as pulmonary oedema. An excessively positive fluid balance has been associated with increased risk of postoperative morbidities, prolonged inpatient stay, organ failure and mortality. Figure 1 demonstrates the challenge.
Emma Tyson MBBCh BSc is Clinical Fellow in Intensive Care at the Royal Surrey County Hospital, Guildford, UK, having completed her core anaesthetics training. Competing interests: none declared. Ben Creagh-Brown BM FRCP PhD DICM FFICM FCCP is Consultant in Intensive Care Medicine, Department of Clinical and Experimental Medicine, University of Surrey, Guildford, UK. He trained in general, respiratory and intensive care medicine. Interests include perioperative care, respiratory failure, muscle wasting and shock. Competing interests: none declared.
MEDICINE --:-
1
Ó 2018 Published by Elsevier Ltd.
Please cite this article in press as: Tyson E, Creagh-Brown B, Postoperative care, Medicine (2018), https://doi.org/10.1016/j.mpmed.2018.09.003
MEDICINE AND OTHER SPECIALTIES
Early nutrition Early oral intake is a key part of ERAS. As surgical stress increases energy expenditure, protein loss and insulin resistance, early resumption of diet helps to counteract this. With most operations, it is possible to start a normal diet the same day, and this has led to a reduced length of stay and reduced morbidity. Early oral intake leads to earlier return of gut function and increased patient satisfaction. In keeping with this, nasogastric tubes are used less often, or removed far sooner. Postoperative ileus describes the failure of return of normal gut function. It is characterized by nausea, vomiting, abdominal distension and a failure to pass flatus or stool per rectum. It is a common reason for delayed discharge in patients undergoing major bowel surgery.
Fluid optimization
Perioperative morbidity risk
Curve represents hypothetical line of risk in relation to fluid load
Expediting recovery through early mobilization Early mobilization reduces the risk of deep vein thrombosis (DVT), ileus and respiratory tract infection, and promotes return to normal activity. Patients should be encouraged to achieve daily goals relevant to their procedure. These can be guided by specific day-by-day checklists that include elements such as exercises, sitting out in a chair and walking. Bed rest is actively discouraged after an operation. Early mobilization preserves muscle mass and promotes muscle strength. Loss of muscle mass by lying immobile in bed for 1 day leads to a 1e3% loss of muscle strength. The rate of loss is greater in elderly patients, and this can ultimately lead to an independent person becoming dependent. Avoiding the insertion, or ensuring the early removal, of drains and catheters reduces patient discomfort and encourages mobility.
Fluid load
Figure 1 Adapted from Bellamy MC. Wet, dry or something else? 2006. Br J Anaesth 97(6): 755e7.
Traditionally, generous amounts of intravenous fluid have been given to correct preoperative deficits and intraoperative losses. This also counteracts loss of fluid from the vascular compartment through bleeding and leaky vasculature (‘thirdspacing’), and vasodilation (often related to epidural analgesia). When hypotension reflects vasodilatation without hypovolaemia, the appropriate therapy is infused vasopressors, with noradrenaline (norepinephrine) being most commonly used. This requires a critical care environment. ERAS pathways have more recently promoted fluid restriction, goal-directed fluid therapy and the concept of ‘zero balance’. A challenge to this increasingly pervasive paradigm is the recent publication of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) study,2 which showed an increased incidence of complications (AKI, surgical site infections) in patients randomized to the restrictive regimen. One approach to limiting postoperative intravenous fluid administration is to promote early oral fluids. This has the additional benefit of liberation from a drip stand, which encourages mobilization.
Postoperative mortality Postoperative complications are estimated to cause about 3 million deaths every year worldwide. Complications experienced during the early postoperative period have long-term adverse effects on mortality.3 It is worthwhile noting that complications are not always avoidable or the result of error. However, when a patient dies because of a complication that was not recognized in a timely fashion or treated appropriately, that death is potentially preventable and is can be termed ‘failure to rescue’.
Critical care after surgery After surgery, some patients return to a ward environment whereas others are given early postoperative care in a critical care environment. In the UK, level 1 care refers to monitoring only, level 2 is high-dependency care (with one nurse to two patients), and level 3 refers to intensive care patients (one-to-one nursing), with increasing levels indicating intensity of intervention. Critical care is suited to those who have already experienced complications of surgery (such as major haemorrhage), are at high risk of developing complications (because of either the patient’s preoperative health status or the nature of the surgery) or require organ-supportive therapies for established organ dysfunction. In some healthcare environments, admission to critical care is required for completion of goal-directed fluid therapy.
Nausea, vomiting and antiemetics These common and unpleasant complications can be related to patient, surgical and anaesthetic factors. Moderate or severe postoperative nausea and vomiting affected 16.5% of patients in the national SNAP-1 study.1 The occurrence of nausea and vomiting can be reduced by screening for risk factors (e.g. surgical: duration of anaesthesia, laparoscopic procedure and patient: age <50, female, history motion sickness) and providing prophylactic multimodal therapies, which often need to be continued postoperatively.
MEDICINE --:-
2
Ó 2018 Published by Elsevier Ltd.
Please cite this article in press as: Tyson E, Creagh-Brown B, Postoperative care, Medicine (2018), https://doi.org/10.1016/j.mpmed.2018.09.003
MEDICINE AND OTHER SPECIALTIES
of death. It typically occurs 24e96 hours after a procedure and manifests as an acute confusional state with disturbance of attention and reduced awareness of the environment. Risk factors include old age, American Society of Anesthesiologists (ASA) physical status grade III or higher, low body mass index, lower serum concentration of albumin, intraoperative hypotension, perioperative blood transfusion and history of alcohol excess. Management starts with recognition, validated assessment tools such as CAM-ICU help diagnosis and monitoring. Treatment is pharmacological and non-pharmacological (including treatment of infection, correction of metabolic derangement and ensuring adequate tissue oxygen delivery). Environment modifications to aid sleep and orientate patients can help. Haloperidol is often used as first line pharmacological intervention.
The large majority of postoperative deaths occur in a small cohort who can readily be identified preoperatively as being high-risk. On the basis that closer observation of these patients in a critical care environment might reduce this risk, higher risk patients are routinely admitted to critical care postoperatively. Although there is some evidence to support this, a recent analysis of the International Surgical Outcomes Study (ISOS) did not identify any survival benefit from critical care admission after surgery.4 A range of tools is available to estimate risk of surgery. The Surgical Outcomes Risk Tool (SORT; www.sortsurgery.com/) and the American College of Surgeons National Surgical Quality Improvement Program (NSQIP; riskcalculator.facs.org/ RiskCalculator/) are widely used and freely available online.
Postoperative pulmonary complications and oxygen therapy
Acute kidney injury
Supplemental oxygen is often required in the early postoperative period to maintain adequate arterial oxygenation. The requirement for supplemental oxygen usually subsides as patients recover, but the most common PPC is a persistent requirement of supplemental oxygen. At the other end of the severity spectrum is respiratory failure, which is often multifactorial and occasionally requires reinstitution of invasive mechanical ventilation. Common factors in the development of most PPCs are contamination of the airways and airway collapse (atelectasis). The latter is caused by the effects of surgery and anaesthesia and is largely inevitable. Impaired respiratory muscle function and lung injury caused by intraoperative invasive mechanical ventilation can contribute. PPCs are serious; even if they are apparently benign, like requiring supplemental oxygen, they are associated with risk of complications and prolonged duration of hospital stay. It is possible to estimate the risk of developing PPCs using validated scoring systems such as Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT).
Postoperative AKI is usually multifactorial; pre-renal causes of low flow (low cardiac output, often caused by hypovolaemia and/or vasodilation) and low filling pressure (from hypotension) are the most common. Important risk factors include pre-existing renal dysfunction, type 1 diabetes mellitus, age >65 years, major vascular surgery, and recent exposure to nephrotoxic agents (e.g. radiocontrast dyes, aminoglycoside antibiotics, NSAIDs). Early detection by monitoring urine output and serum urea and electrolytes is important. AKI is best prevented by maintaining euvolaemia. It is best treated by optimizing conditions for renal recovery (optimal fluid balance, adequate blood pressure and flow) and avoiding further injury (nephrotoxins). Patients experiencing severe AKI may require treatment with renal replacement therapy, although this is uncommon after noncardiac surgery.
Surgical site infection Surgical site infections occur in 5% of patients. Risk factors include contamination during surgery (e.g. bowel perforation), long operative duration and impaired patient immunity (e.g. diabetes mellitus, cancer). Indwelling lines, catheters and drains should be reviewed daily to assess suitability for removal.
Cardiovascular complications Classical myocardial infarction is uncommon after non-cardiac surgery. However, asymptomatic elevations in the cardiac biomarker troponin are common and have prognostic significance e in the Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) study, 17.9% of patients undergoing non-cardiac surgery fulfilled the criteria for myocardial injury after non-cardiac surgery (MINS), and this was associated with increased risk of 30-day mortality.5 The cause of death is, however, usually not cardiac, and without evidence of benefit for screening it is uncertain how this is best managed. Atrial fibrillation occurs in 7e15% of patients having noncardiac surgery, compared with 16e30% with cardiac surgery. Risk factors include increasing age, history of cardiac disease and postoperative complications, particularly sepsis, pneumonia and pleural effusions.
Glucose control Hyperglycaemia is common in postoperative ICU patients (even those previously with no history of diabetes) as part of the stress response to major surgery. It is associated with increased risk of a wide range of postoperative complications, but this risk can be mitigated by optimal use of insulin infusions. As aiming for very tight glycaemic control is associated with significant risk of harmful hypoglycaemia, the recommended course of action is monitoring and selective use of variable-rate insulin infusions, without overly strict targets. Depending on the duration of starvation, it may be appropriate to continue long-acting subcutaneous insulin, albeit at 80% of the usual dose. Barriers to administering oral hypoglycaemic agents in postoperative inpatients include variability in caloric intake, ileus and limited ability to titrate the drugs. When patients are eating and drinking, oral hypoglycaemia agents should be restarted, except for metformin, which should be withheld until renal function returns to normal.
Delirium Delirium is a common complication of surgery and is associated with increased risk of prolonged hospital stay and increased risk
MEDICINE --:-
3
Ó 2018 Published by Elsevier Ltd.
Please cite this article in press as: Tyson E, Creagh-Brown B, Postoperative care, Medicine (2018), https://doi.org/10.1016/j.mpmed.2018.09.003
MEDICINE AND OTHER SPECIALTIES
Prophylaxis against venous thromboembolism
patients undergoing noncardiac surgery. JAMA 2017; 317: 1642e51.
DVT and pulmonary embolism are common complications of major surgery unless prophylaxis is provided. Every hospital inpatient should be assessed for risk of venous thromboembolism and risk of bleeding. It is often appropriate to use both pharmacological prophylaxis (usually daily low-molecularweight heparin) and thromboembolism deterrent stockings. A
FURTHER READING A systematic review of the incidence of and risk factors for postoperative atrial fibrillation following general surgery. Anaesthesia 2018; 73: 490e8. Farhan H, et al. Acquired muscle weakness in the surgical ICU. Nosology, epidemiology, diagnosis and prevention. Anaesthesiology 2016; 124: 207e34. Frisch A, et al. Prevalence and clinical outcome of hyperglycaemia in the perioperative period in noncardiac surgery. Diabetes Care 2010; 33: 783e8. Gallart L, Canet J. Post-operative pulmonary complications. Anesthesiology 2014; 29: 219e31. Pearse RM, et al. Identification and characterisation of the high-risk surgical population in the United Kingdom. Crit Care 2006; 10: R81.
KEY REFERENCES 1 Walker EM, et al. Patient reported outcome of adult perioperative adult anaesthesia in the United Kingdom: a cross-sectional observational study. Br J Anaesth 2016; 117: 758e66. 2 Myles PS, et al. Restrictive versus liberal fluid therapy for major abdominal surgery. N Engl J Med 2018; 378: 2263e74. 3 Khuri SF, et al. Determinants of long-term survival after major surgery and the adverse effect of postoperative complications. Ann Surg 2005; 242: 326e43. 4 Brennan CK, et al. Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries. Intensive Care Med 2017; 43: 971e9. 5 Devereaux PJ, et al. Association of postoperative high-sensitivity troponin levels with myocardial injury and 30-day mortality among
Acknowledgements The authors thank Dr Bill Fawcett for his expert advice.
TEST YOURSELF To test your knowledge based on the article you have just read, please complete the questions below. The answers can be found at the end of the issue or online here. Which factor best predicts severe postoperative pain on this occasion? A Age B Previous postoperative vomiting C BMI D Female gender E History of fibromyalgia
Question 1 A 66-year-old man was scheduled for an open elective right hemicolectomy for colon cancer. He had a past medical history of hypertension and chronic obstructive pulmonary disease, and needed to stop when reaching the top of a flight of stairs, because of breathlessness. What is his calculated 30-day mortality using the SORT calculator (www.sortsurgery.com)? A) 30.12% B) 0.01% C) 3.17% D) 8.01% E) 22.19%
Question 3 A 57-year-old woman underwent uncomplicated elective laparoscopic anterior resection for colon cancer. Postoperatively, she was commenced on an early oral intake regimen as advised by the hospital’s protocol. What is the most likely important consequence of this policy? A Decreased morbidity B Decreased insulin resistance C Decreased intravenous fluids D Decreased use of a nasogastric tube E Decreased risk of postoperative ileus
Question 2 A 58-year-old woman was due to undergo elective cholecystectomy for gallstones. She had a past history of fibromyalgia treated at times with opiates and also vomited in the hours following a previous hysterectomy. On clinical examination, BMI is 35 kg/m2.
MEDICINE --:-
4
Ó 2018 Published by Elsevier Ltd.
Please cite this article in press as: Tyson E, Creagh-Brown B, Postoperative care, Medicine (2018), https://doi.org/10.1016/j.mpmed.2018.09.003
Postoperative care
Key points
Emma Tyson
C
Enhanced recovery protocols use a combination of evidencebased elements to reduce hospital length of stay and postoperative morbidity. This improves the patient’s recovery and has financial benefits for the hospital
C
Immobility in bed leads to a loss of 1e3% muscle mass per day. The benefits of mobilization should be emphasized, and patients should be encouraged to mobilize by healthcare staff and relatives
C
Early oral intake leads to earlier return of gut function and reduces the effects of surgical stress
C
Early oral fluids reduce intravenous fluid use and can assist with the challenge of perioperative fluid management. This also encourages mobilization
C
Postoperative complications are important causes of morbidity and mortality, and lack of early assessment and intervention can lead to ‘failure to rescue’. Around 80% of inpatient postoperative deaths occur in 15% of patients who have preoperatively identifiable risk factors
Ben Creagh-Brown
Abstract Optimal postoperative care involves a multidisciplinary team of healthcare professionals and a patient-centred approach to avoid postoperative complications and enable a rapid return to normal function. During the last decade, enhanced recovery after surgery programmes have been implemented worldwide to reduce complications and length of stay e challenging traditional models of perioperative care. Some aspects of perioperative care have consensus guidelines without significant controversy, whereas others, such as perioperative fluid therapy, remain contentious.
Keywords Enhanced recovery; fluid management; myocardial injury after non-cardiac surgery; perioperative care; pulmonary complications
Introduction The aims of postoperative care are to restore physiological function, prevent complications and prevent the need for a prolonged stay in hospital. Enhanced recovery after surgery (ERAS; www.erassociety.org) is an evidence-based, multifaceted, patient-centred programme that has been shown to reduce postoperative complications and hospital length of stay. It has been adopted by many surgical specialties. ERAS programmes include pre-, intra- and postoperative elements.
neuropathic pain or chronic opioid use. Patient counselling is important to manage expectations as it is recognized that anxiety increases pain perception. Relief of pain allows patients to cough, breathe effectively and move e all of which are beneficial. Traditional postoperative opiate use has undesirable dose-related adverse effects such as nausea, constipation, vomiting, dizziness, confusion and respiratory depression. Opiates usually cause constipation, so all patients given opiates should be prescribed regular laxatives to mitigate this. Effective pain relief can also reduce the incidence of chronic pain syndromes. Inadequate pain management can lead to reduced deep breathing and limited mobility, both of which predispose to the development of postoperative pulmonary complications (PPCs).
Pain and multimodal opiate-sparing analgesia Multimodal opiate-sparing analgesia refers to the use of a variety of analgesic agents, working via different mechanisms, to minimize opiate use. They typically include acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs) and local, regional or neuraxial analgesics. Other agents include gabapentin, lidocaine, clonidine and ketamine. Patients commonly fear that they will experience pain after an operation, although severe surgical pain only affected 11% in the Sprint National Anaesthesia Project (SNAP-1) national study.1 Risk factors for severe discomfort included younger age, female sex, obesity, history of stroke or transient ischaemic attack and
Perioperative fluid management Postoperative fluid management remains a contentious and challenging issue for clinicians. The difficulty in accurately assessing hydration status, even with advanced monitoring, means that achievement of optimal balance remains elusive. Inadequate fluid administration leads to hypovolaemia, which contributes to decreased organ perfusion; this can manifest in a range of ways, including acute kidney injury (AKI). By contrast, excessive fluid administration leads to electrolyte disturbances and water overload, which causes oedema and can manifest as pulmonary oedema. An excessively positive fluid balance has been associated with increased risk of postoperative morbidities, prolonged inpatient stay, organ failure and mortality. Figure 1 demonstrates the challenge.
Emma Tyson MBBCh BSc is Clinical Fellow in Intensive Care at the Royal Surrey County Hospital, Guildford, UK, having completed her core anaesthetics training. Competing interests: none declared. Ben Creagh-Brown BM FRCP PhD DICM FFICM FCCP is Consultant in Intensive Care Medicine, Department of Clinical and Experimental Medicine, University of Surrey, Guildford, UK. He trained in general, respiratory and intensive care medicine. Interests include perioperative care, respiratory failure, muscle wasting and shock. Competing interests: none declared.
MEDICINE --:-
1
Ó 2018 Published by Elsevier Ltd.
Please cite this article in press as: Tyson E, Creagh-Brown B, Postoperative care, Medicine (2018), https://doi.org/10.1016/j.mpmed.2018.09.003
MEDICINE AND OTHER SPECIALTIES
Early nutrition Early oral intake is a key part of ERAS. As surgical stress increases energy expenditure, protein loss and insulin resistance, early resumption of diet helps to counteract this. With most operations, it is possible to start a normal diet the same day, and this has led to a reduced length of stay and reduced morbidity. Early oral intake leads to earlier return of gut function and increased patient satisfaction. In keeping with this, nasogastric tubes are used less often, or removed far sooner. Postoperative ileus describes the failure of return of normal gut function. It is characterized by nausea, vomiting, abdominal distension and a failure to pass flatus or stool per rectum. It is a common reason for delayed discharge in patients undergoing major bowel surgery.
Fluid optimization
Perioperative morbidity risk
Curve represents hypothetical line of risk in relation to fluid load
Expediting recovery through early mobilization Early mobilization reduces the risk of deep vein thrombosis (DVT), ileus and respiratory tract infection, and promotes return to normal activity. Patients should be encouraged to achieve daily goals relevant to their procedure. These can be guided by specific day-by-day checklists that include elements such as exercises, sitting out in a chair and walking. Bed rest is actively discouraged after an operation. Early mobilization preserves muscle mass and promotes muscle strength. Loss of muscle mass by lying immobile in bed for 1 day leads to a 1e3% loss of muscle strength. The rate of loss is greater in elderly patients, and this can ultimately lead to an independent person becoming dependent. Avoiding the insertion, or ensuring the early removal, of drains and catheters reduces patient discomfort and encourages mobility.
Fluid load
Figure 1 Adapted from Bellamy MC. Wet, dry or something else? 2006. Br J Anaesth 97(6): 755e7.
Traditionally, generous amounts of intravenous fluid have been given to correct preoperative deficits and intraoperative losses. This also counteracts loss of fluid from the vascular compartment through bleeding and leaky vasculature (‘thirdspacing’), and vasodilation (often related to epidural analgesia). When hypotension reflects vasodilatation without hypovolaemia, the appropriate therapy is infused vasopressors, with noradrenaline (norepinephrine) being most commonly used. This requires a critical care environment. ERAS pathways have more recently promoted fluid restriction, goal-directed fluid therapy and the concept of ‘zero balance’. A challenge to this increasingly pervasive paradigm is the recent publication of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) study,2 which showed an increased incidence of complications (AKI, surgical site infections) in patients randomized to the restrictive regimen. One approach to limiting postoperative intravenous fluid administration is to promote early oral fluids. This has the additional benefit of liberation from a drip stand, which encourages mobilization.
Postoperative mortality Postoperative complications are estimated to cause about 3 million deaths every year worldwide. Complications experienced during the early postoperative period have long-term adverse effects on mortality.3 It is worthwhile noting that complications are not always avoidable or the result of error. However, when a patient dies because of a complication that was not recognized in a timely fashion or treated appropriately, that death is potentially preventable and is can be termed ‘failure to rescue’.
Critical care after surgery After surgery, some patients return to a ward environment whereas others are given early postoperative care in a critical care environment. In the UK, level 1 care refers to monitoring only, level 2 is high-dependency care (with one nurse to two patients), and level 3 refers to intensive care patients (one-to-one nursing), with increasing levels indicating intensity of intervention. Critical care is suited to those who have already experienced complications of surgery (such as major haemorrhage), are at high risk of developing complications (because of either the patient’s preoperative health status or the nature of the surgery) or require organ-supportive therapies for established organ dysfunction. In some healthcare environments, admission to critical care is required for completion of goal-directed fluid therapy.
Nausea, vomiting and antiemetics These common and unpleasant complications can be related to patient, surgical and anaesthetic factors. Moderate or severe postoperative nausea and vomiting affected 16.5% of patients in the national SNAP-1 study.1 The occurrence of nausea and vomiting can be reduced by screening for risk factors (e.g. surgical: duration of anaesthesia, laparoscopic procedure and patient: age <50, female, history motion sickness) and providing prophylactic multimodal therapies, which often need to be continued postoperatively.
MEDICINE --:-
2
Ó 2018 Published by Elsevier Ltd.
Please cite this article in press as: Tyson E, Creagh-Brown B, Postoperative care, Medicine (2018), https://doi.org/10.1016/j.mpmed.2018.09.003
MEDICINE AND OTHER SPECIALTIES
of death. It typically occurs 24e96 hours after a procedure and manifests as an acute confusional state with disturbance of attention and reduced awareness of the environment. Risk factors include old age, American Society of Anesthesiologists (ASA) physical status grade III or higher, low body mass index, lower serum concentration of albumin, intraoperative hypotension, perioperative blood transfusion and history of alcohol excess. Management starts with recognition, validated assessment tools such as CAM-ICU help diagnosis and monitoring. Treatment is pharmacological and non-pharmacological (including treatment of infection, correction of metabolic derangement and ensuring adequate tissue oxygen delivery). Environment modifications to aid sleep and orientate patients can help. Haloperidol is often used as first line pharmacological intervention.
The large majority of postoperative deaths occur in a small cohort who can readily be identified preoperatively as being high-risk. On the basis that closer observation of these patients in a critical care environment might reduce this risk, higher risk patients are routinely admitted to critical care postoperatively. Although there is some evidence to support this, a recent analysis of the International Surgical Outcomes Study (ISOS) did not identify any survival benefit from critical care admission after surgery.4 A range of tools is available to estimate risk of surgery. The Surgical Outcomes Risk Tool (SORT; www.sortsurgery.com/) and the American College of Surgeons National Surgical Quality Improvement Program (NSQIP; riskcalculator.facs.org/ RiskCalculator/) are widely used and freely available online.
Postoperative pulmonary complications and oxygen therapy
Acute kidney injury
Supplemental oxygen is often required in the early postoperative period to maintain adequate arterial oxygenation. The requirement for supplemental oxygen usually subsides as patients recover, but the most common PPC is a persistent requirement of supplemental oxygen. At the other end of the severity spectrum is respiratory failure, which is often multifactorial and occasionally requires reinstitution of invasive mechanical ventilation. Common factors in the development of most PPCs are contamination of the airways and airway collapse (atelectasis). The latter is caused by the effects of surgery and anaesthesia and is largely inevitable. Impaired respiratory muscle function and lung injury caused by intraoperative invasive mechanical ventilation can contribute. PPCs are serious; even if they are apparently benign, like requiring supplemental oxygen, they are associated with risk of complications and prolonged duration of hospital stay. It is possible to estimate the risk of developing PPCs using validated scoring systems such as Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT).
Postoperative AKI is usually multifactorial; pre-renal causes of low flow (low cardiac output, often caused by hypovolaemia and/or vasodilation) and low filling pressure (from hypotension) are the most common. Important risk factors include pre-existing renal dysfunction, type 1 diabetes mellitus, age >65 years, major vascular surgery, and recent exposure to nephrotoxic agents (e.g. radiocontrast dyes, aminoglycoside antibiotics, NSAIDs). Early detection by monitoring urine output and serum urea and electrolytes is important. AKI is best prevented by maintaining euvolaemia. It is best treated by optimizing conditions for renal recovery (optimal fluid balance, adequate blood pressure and flow) and avoiding further injury (nephrotoxins). Patients experiencing severe AKI may require treatment with renal replacement therapy, although this is uncommon after noncardiac surgery.
Surgical site infection Surgical site infections occur in 5% of patients. Risk factors include contamination during surgery (e.g. bowel perforation), long operative duration and impaired patient immunity (e.g. diabetes mellitus, cancer). Indwelling lines, catheters and drains should be reviewed daily to assess suitability for removal.
Cardiovascular complications Classical myocardial infarction is uncommon after non-cardiac surgery. However, asymptomatic elevations in the cardiac biomarker troponin are common and have prognostic significance e in the Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) study, 17.9% of patients undergoing non-cardiac surgery fulfilled the criteria for myocardial injury after non-cardiac surgery (MINS), and this was associated with increased risk of 30-day mortality.5 The cause of death is, however, usually not cardiac, and without evidence of benefit for screening it is uncertain how this is best managed. Atrial fibrillation occurs in 7e15% of patients having noncardiac surgery, compared with 16e30% with cardiac surgery. Risk factors include increasing age, history of cardiac disease and postoperative complications, particularly sepsis, pneumonia and pleural effusions.
Glucose control Hyperglycaemia is common in postoperative ICU patients (even those previously with no history of diabetes) as part of the stress response to major surgery. It is associated with increased risk of a wide range of postoperative complications, but this risk can be mitigated by optimal use of insulin infusions. As aiming for very tight glycaemic control is associated with significant risk of harmful hypoglycaemia, the recommended course of action is monitoring and selective use of variable-rate insulin infusions, without overly strict targets. Depending on the duration of starvation, it may be appropriate to continue long-acting subcutaneous insulin, albeit at 80% of the usual dose. Barriers to administering oral hypoglycaemic agents in postoperative inpatients include variability in caloric intake, ileus and limited ability to titrate the drugs. When patients are eating and drinking, oral hypoglycaemia agents should be restarted, except for metformin, which should be withheld until renal function returns to normal.
Delirium Delirium is a common complication of surgery and is associated with increased risk of prolonged hospital stay and increased risk
MEDICINE --:-
3
Ó 2018 Published by Elsevier Ltd.
Please cite this article in press as: Tyson E, Creagh-Brown B, Postoperative care, Medicine (2018), https://doi.org/10.1016/j.mpmed.2018.09.003
MEDICINE AND OTHER SPECIALTIES
Prophylaxis against venous thromboembolism
patients undergoing noncardiac surgery. JAMA 2017; 317: 1642e51.
DVT and pulmonary embolism are common complications of major surgery unless prophylaxis is provided. Every hospital inpatient should be assessed for risk of venous thromboembolism and risk of bleeding. It is often appropriate to use both pharmacological prophylaxis (usually daily low-molecularweight heparin) and thromboembolism deterrent stockings. A
FURTHER READING A systematic review of the incidence of and risk factors for postoperative atrial fibrillation following general surgery. Anaesthesia 2018; 73: 490e8. Farhan H, et al. Acquired muscle weakness in the surgical ICU. Nosology, epidemiology, diagnosis and prevention. Anaesthesiology 2016; 124: 207e34. Frisch A, et al. Prevalence and clinical outcome of hyperglycaemia in the perioperative period in noncardiac surgery. Diabetes Care 2010; 33: 783e8. Gallart L, Canet J. Post-operative pulmonary complications. Anesthesiology 2014; 29: 219e31. Pearse RM, et al. Identification and characterisation of the high-risk surgical population in the United Kingdom. Crit Care 2006; 10: R81.
KEY REFERENCES 1 Walker EM, et al. Patient reported outcome of adult perioperative adult anaesthesia in the United Kingdom: a cross-sectional observational study. Br J Anaesth 2016; 117: 758e66. 2 Myles PS, et al. Restrictive versus liberal fluid therapy for major abdominal surgery. N Engl J Med 2018; 378: 2263e74. 3 Khuri SF, et al. Determinants of long-term survival after major surgery and the adverse effect of postoperative complications. Ann Surg 2005; 242: 326e43. 4 Brennan CK, et al. Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries. Intensive Care Med 2017; 43: 971e9. 5 Devereaux PJ, et al. Association of postoperative high-sensitivity troponin levels with myocardial injury and 30-day mortality among
Acknowledgements The authors thank Dr Bill Fawcett for his expert advice.
TEST YOURSELF To test your knowledge based on the article you have just read, please complete the questions below. The answers can be found at the end of the issue or online here. Which factor best predicts severe postoperative pain on this occasion? A Age B Previous postoperative vomiting C BMI D Female gender E History of fibromyalgia
Question 1 A 66-year-old man was scheduled for an open elective right hemicolectomy for colon cancer. He had a past medical history of hypertension and chronic obstructive pulmonary disease, and needed to stop when reaching the top of a flight of stairs, because of breathlessness. What is his calculated 30-day mortality using the SORT calculator (www.sortsurgery.com)? A) 30.12% B) 0.01% C) 3.17% D) 8.01% E) 22.19%
Question 3 A 57-year-old woman underwent uncomplicated elective laparoscopic anterior resection for colon cancer. Postoperatively, she was commenced on an early oral intake regimen as advised by the hospital’s protocol. What is the most likely important consequence of this policy? A Decreased morbidity B Decreased insulin resistance C Decreased intravenous fluids D Decreased use of a nasogastric tube E Decreased risk of postoperative ileus
Question 2 A 58-year-old woman was due to undergo elective cholecystectomy for gallstones. She had a past history of fibromyalgia treated at times with opiates and also vomited in the hours following a previous hysterectomy. On clinical examination, BMI is 35 kg/m2.
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Ó 2018 Published by Elsevier Ltd.
Please cite this article in press as: Tyson E, Creagh-Brown B, Postoperative care, Medicine (2018), https://doi.org/10.1016/j.mpmed.2018.09.003