Shock, Fluids, Nutrition and Transfusion MCQs

Surgery · 111 free questions with answers & explanations.

1. A 30-year-old woman sustains a road traffic accident with multiple pelvic fractures. On arrival she has HR 128/min, BP 88/60 mmHg, respiratory rate 26/min, and is confused. Estimated blood loss is approximately 2.5 litres. According to ATLS classification, she is in:
2. A critically ill patient in the surgical ICU is unable to tolerate enteral feeding due to an enterocutaneous fistula with high output. He requires total parenteral nutrition. Which vein is the preferred access site for long-term TPN?
3. A post-operative patient on TPN develops fever, elevated blood glucose, and hypertriglyceridaemia. His central line was placed 12 days ago. Blood cultures grow Candida albicans. The most appropriate action regarding the central venous catheter (CVC) is:
4. A 70 kg trauma patient receives 4 units of packed red blood cells (PRBCs), 4 units of fresh frozen plasma (FFP), and 1 apheresis platelet unit (equivalent to 5 pooled units). Which complication of massive transfusion is specifically prevented by this 1:1:1 ratio protocol?
5. A 70 kg patient undergoing elective colectomy receives 6 units of packed red cells over 4 hours due to intraoperative haemorrhage. The most important physiological effect of transfusing large volumes of stored packed red cells (>14 days storage) is:
6. In a critically ill surgical patient requiring parenteral nutrition, refeeding syndrome is a potentially fatal complication. The metabolic hallmark and the electrolyte most critically depleted during refeeding syndrome is:
7. A 70 kg, 55-year-old man undergoes a 4-hour major abdominal surgery. Postoperatively, he has received 4L of crystalloid intraoperatively. On Day 1 post-op, he is anuric (urine output 10 mL/hour), BP 100/65 mmHg, HR 98 bpm, JVP is normal, chest is clear, and serum lactate is 3.2 mmol/L. A fluid responsiveness test using passive leg raising (PLR) shows no change in stroke volume (SV). The most appropriate interpretation and management is:
8. A 68-year-old man is being assessed for major colorectal surgery. Pre-operative nutritional assessment shows severe malnutrition (NRS-2002 score ≥5, serum albumin 25 g/L, BMI 17, weight loss 12% in 3 months). He has no signs of intestinal obstruction. The ESPEN 2017 guideline recommendation for pre-operative nutritional support in this severely malnourished patient is:
9. The SAFE trial (Saline versus Albumin Fluid Evaluation) demonstrated which key finding regarding resuscitation fluids in critically ill patients?
10. Enhanced Recovery After Surgery (ERAS) protocols have transformed perioperative care. Which of the following is a core ERAS element supported by highest-level evidence that directly reduces length of hospital stay after colorectal surgery?
11. In massive transfusion protocols (MTP), the PROPPR trial (2015) established an optimal ratio for plasma:platelets:packed red blood cells. What ratio was demonstrated to improve 24-hour survival and hemostasis?
12. Regarding parenteral nutrition in surgical patients, which substrate is preferred as the primary energy source, and what is the recommended caloric ratio of non-protein to protein calories?
13. A 60-year-old septic patient in the ICU has serum sodium of 130 mEq/L, serum albumin 22 g/L, and is on total parenteral nutrition (TPN). The decision is made to start enteral nutrition. According to ESPEN 2023 guidelines, which parameter should guide the timing of enteral nutrition in critically ill patients?
14. The ATBF (Albumin, Blood, Fluid) algorithm for colloid versus crystalloid resuscitation has been largely supplanted by evidence. The SAFE trial (2004) comparing albumin versus saline in ICU patients found that albumin was associated with increased mortality in which specific patient subgroup?
15. A 65-year-old post-operative patient in the ICU develops vasodilatory shock with warm peripheries, high cardiac output, and low SVR following laparotomy for perforated bowel. Norepinephrine is titrated to 0.5 mcg/kg/min. According to current SCCM SURVIVE SEPSIS guidelines (2021), which adjunctive vasopressor should be added NEXT to reduce norepinephrine requirements?
16. Refeeding syndrome occurs when severely malnourished patients receive aggressive nutritional support. The hallmark biochemical abnormality that drives its clinical manifestations (arrhythmias, respiratory failure, hemolysis) is:
17. For a critically ill surgical patient in ICU requiring nutritional support, which route is preferred when the GI tract is functioning?
18. The CALORIES trial (UK) compared parenteral nutrition (PN) versus enteral nutrition (EN) initiated via the nasogastric route in ICU patients unable to receive oral feeding. What was its primary conclusion?
19. A 70 kg patient with septic shock has received 4 L of 0.9% normal saline resuscitation in 6 hours and remains oliguric with worsening metabolic acidosis. Serum chloride is 120 mEq/L. What is the likely acid-base diagnosis and preferred resuscitation fluid?
20. A 65-year-old man with septic shock following Hartmann's reversal surgery is on mechanical ventilation. After 3 litres of fluid resuscitation, CVP is 12 mmHg, MAP is still 58 mmHg, and lactate is 5 mmol/L at 6 hours. According to the Surviving Sepsis Campaign 2021 guidelines, which parameter best guides further fluid administration?
21. A critically ill surgical patient requires parenteral nutrition (PN). Nitrogen requirement is estimated at 0.25 g/kg/day. Body weight is 70 kg. What is the required amino acid input per day, and which complication is most specific to PN administered through a peripheral vein rather than a central catheter?
22. A 65-year-old ICU patient on mechanical ventilation post-laparotomy for bowel perforation has a CVP of 6 mmHg and MAP of 60 mmHg. Fluid bolus fails to improve MAP. Lactate is 4.2 mmol/L. ScvO2 is 58%. According to Surviving Sepsis Campaign 2021 guidelines, the next intervention after ensuring adequate fluid resuscitation is:
23. A surgical patient is started on total parenteral nutrition (TPN). On day 3, serum phosphate drops to 0.4 mmol/L (normal 0.8-1.45) with onset of muscle weakness and confusion. The most likely diagnosis and its mechanism is:
24. A 55-year-old patient with a head injury (GCS 9) is intubated and mechanically ventilated. The ICU team initiates nutritional support. According to ESPEN 2019 ICU nutrition guidelines, enteral nutrition should be initiated:
25. A 68-year-old patient develops distributive shock 48 hours after an elective colectomy for sigmoid cancer. BP is 75/40 mmHg, HR 130 bpm, temperature 38.9°C, and lactate 4.2 mmol/L. She is on mechanical ventilation in ICU. Blood cultures are sent. According to the Surviving Sepsis Campaign (SSC) 2021 Hour-1 Bundle, which combination of actions should be initiated within 1 hour?
26. A 55-year-old malnourished patient with Crohn's disease requires bowel resection. Preoperative nutritional assessment reveals severe malnutrition (weight loss 18% over 3 months, BMI 16.5 kg/m², albumin 22 g/L). She is unable to take adequate oral nutrition. According to ESPEN guidelines for preoperative nutritional support, refeeding syndrome risk must be considered when initiating enteral nutrition. Which electrolyte combination is most characteristic of refeeding syndrome?
27. In a patient with massive hemorrhage requiring massive transfusion protocol (MTP), the current evidence-based ratio for packed red blood cells (pRBCs), fresh frozen plasma (FFP), and platelets is:
28. A ventilated ICU patient following major abdominal surgery is unable to commence enteral nutrition due to high gastric residuals. According to ESPEN 2023 guidelines, which route and timing of nutrition support is recommended?
29. Which colloid solution is associated with dose-dependent coagulopathy (reduction in von Willebrand factor and Factor VIII activity) and is now contraindicated in ICU and trauma patients based on CHEST and 6S trial evidence?
30. A 70 kg critically ill post-operative patient develops septic shock. Fluid resuscitation with 30 mL/kg crystalloid (2,100 mL) has been administered. CVP is 12 mmHg, MAP remains 58 mmHg, lactate is 4.2 mmol/L, ScvO2 is 68%. What is the next step per SSC (Surviving Sepsis Campaign) 2021 bundle?
31. A 65-year-old patient is undergoing major upper GI cancer surgery and will be unable to tolerate oral intake for at least 7 days post-operatively. Preoperative nutritional assessment shows albumin 28 g/L and BMI 18.5 kg/m². What is the most appropriate nutritional strategy per ESPEN guidelines?
32. A trauma patient with a large hemothorax following penetrating chest trauma receives 4 units pRBC, 4 units FFP, and 1 pool of platelets in the first hour. This represents a ratio of 1:1:1. What is the physiological rationale for this 'damage control resuscitation' strategy based on PROPPR trial findings?
33. A critically ill patient in surgical ICU has been nil by mouth for 7 days on parenteral nutrition. Serum phosphate drops to 0.4 mmol/L (normal 0.8–1.45) and the patient develops respiratory failure and cardiac arrhythmias. What is this syndrome and which electrolyte is the primary driver?
34. Following total gastrectomy, a patient develops megaloblastic anaemia 3 years post-operatively. Serum B12 is 80 pg/mL. Schilling test (if available) would show malabsorption corrected by intrinsic factor. What is the mechanism and long-term management?
35. A 55-year-old ICU patient post-Whipple procedure develops renal failure and requires fluid resuscitation. A randomised trial is cited to choose between normal saline and balanced crystalloid. Which trial demonstrated that balanced crystalloids (Lactated Ringer's or PlasmaLyte) reduced major adverse kidney events at 30 days compared to 0.9% saline in critically ill adults?
36. A critically ill mechanically ventilated patient in the surgical ICU cannot tolerate enteral nutrition due to high gastric residual volumes. On day 4, a decision about parenteral nutrition (PN) is being made. According to the EPANIC (Early Parenteral Nutrition) trial findings, what is the most evidence-based approach?
37. A 70-year-old man undergoing elective colorectal surgery is given restrictive transfusion strategy. The TRICC trial threshold for RBC transfusion in non-cardiac critically ill patients and the FOCUS trial for hip fracture surgery both established which haemoglobin trigger as safe for transfusion in haemodynamically stable patients?
38. A post-operative bowel resection patient is being started on total parenteral nutrition (TPN). On day 3, serum phosphate drops to 0.4 mmol/L; the patient develops weakness, cardiac arrhythmias, and altered sensorium. What is the most likely metabolic complication?
39. Which ATLS classification of hemorrhagic shock is characterized by a heart rate of 120–140 bpm, BP 90–100 mmHg systolic, decreased pulse pressure, urine output 5–15 mL/hr, and estimated blood loss of 1500–2000 mL?
40. Massive transfusion protocol (MTP) for trauma haemorrhage guides empiric blood product ratios before laboratory results. The current evidence-based ratio from the PROPPR trial is:
41. The CALORIES trial compared parenteral nutrition (PN) versus enteral nutrition (EN) in critically ill ICU patients unable to tolerate full enteral feeding. The primary outcome difference was:
42. In a post-operative patient developing SIRS with suspected early sepsis, the Surviving Sepsis Campaign 2021 hour-1 bundle includes which combination of interventions?
43. According to ESPEN 2023 guidelines for perioperative nutrition in elective major abdominal surgery, what is the preferred route and timing of nutritional support when oral intake is inadequate postoperatively?
44. A 25-year-old trauma patient has an estimated blood loss of 1800 mL. Heart rate is 128 bpm, blood pressure 90/60 mmHg, respiratory rate 30/min, GCS 13, urine output 20 mL/hour. According to ATLS haemorrhagic shock classification, this is:
45. A post-operative patient in surgical ICU has a serum sodium of 128 mEq/L. Review of his fluid chart shows he has received 3 litres of 5% dextrose since the operation. His urine sodium is 40 mEq/L and osmolality is 280 mOsm/kg. He is asymptomatic but the team is planning correction. What is the maximum safe rate of sodium correction per 24 hours to avoid central pontine myelinolysis?
46. A patient receives a blood transfusion and within 15 minutes develops fever, rigors, hypotension, haemoglobinuria, and flank pain. The most likely diagnosis and initial management are:
47. A 45-year-old post-operative patient develops oliguria (urine output 15 mL/h), BP 85/50 mmHg, CVP 2 cmH2O, cold peripheries, and clear lung fields. Cardiac output monitoring shows cardiac output 2.1 L/min and systemic vascular resistance (SVR) 2,800 dyne·s·cm⁻⁵. This haemodynamic profile is MOST consistent with:
48. The ATLS classification of haemorrhagic shock divides blood loss into four classes. A 70 kg patient with Class III haemorrhage would show approximate blood loss of:
49. Transfusion-associated circulatory overload (TACO) and transfusion-related acute lung injury (TRALI) are both complications of blood transfusion presenting with acute respiratory distress. Which feature BEST distinguishes TRALI from TACO?
50. A 60-year-old man is ventilated in ICU following major abdominal surgery. He has a nasogastric tube in situ. On day 3 post-op, ileus is resolving. Enteral nutrition is being initiated. Refeeding syndrome is a concern. Which electrolyte abnormality is the HALLMARK of refeeding syndrome and its primary dangerous manifestation?
51. ATLS 10th edition classifies haemorrhagic shock based on physiological parameters. Class III haemorrhagic shock is characterised by blood loss of approximately:
52. The TRICC trial established a restrictive versus liberal transfusion strategy in critically ill patients. The threshold for red blood cell transfusion in the restrictive group was Hb <7 g/dL (target 7–9 g/dL), versus Hb <10 g/dL in the liberal group. The trial showed:
53. In the management of short bowel syndrome (SBS) following massive small bowel resection, the minimum residual small bowel length associated with a reasonable chance of weaning from parenteral nutrition (PN) is approximately:
54. A 70 kg trauma patient has lost an estimated 2.1L of blood with BP 90/70 mmHg, HR 130/min, RR 28/min, and confusion. According to ATLS classification, what class of hemorrhagic shock is this, and what is the estimated percentage blood volume loss?
55. A 55-year-old patient after major abdominal surgery is being assessed for nutritional support. Which of the following best reflects the current evidence from the ERAS (Enhanced Recovery After Surgery) protocol regarding perioperative nutrition?
56. A trauma patient in hemorrhagic shock is being transfused using massive transfusion protocol (MTP). According to current evidence-based guidelines, what is the optimal ratio of packed red blood cells (pRBC) : fresh frozen plasma (FFP) : platelets?
57. A post-operative cardiac surgery patient develops distributive shock (MAP <65 mmHg) despite adequate fluid resuscitation. Norepinephrine is the first-choice vasopressor. According to the VASST trial, when should vasopressin be added?
58. The SAFE (Saline versus Albumin Fluid Evaluation) study demonstrated that in critically ill patients requiring fluid resuscitation, albumin solution compared to normal saline was associated with:
59. Refeeding syndrome is a potentially fatal complication of recommencing nutrition in severely malnourished patients. The biochemical hallmark and primary driver of refeeding syndrome is:
60. In septic shock with suspected intra-abdominal source, which aspect of the Surviving Sepsis Campaign 'Hour-1 Bundle' (2018) has been most controversially debated following the FEAST and PROCESS/ARISE/ProMISe trials?
61. The CALORIES trial compared parenteral nutrition (PN) versus enteral nutrition (EN) for critically ill patients who could not receive early enteral nutrition. The trial found:
62. A 55-year-old postoperative patient develops hypotension (BP 85/50), tachycardia (HR 128), warm peripheries, SpO2 94% on room air, and lactate 4.2 mmol/L after abdominal surgery. Cultures are sent. The Surviving Sepsis Campaign (2021) mandates which intervention within 1 hour?
63. Regarding massive transfusion protocol (MTP) in damage control resuscitation, the recommended ratio of packed red blood cells (pRBC): fresh frozen plasma (FFP): platelets is:
64. A 60-year-old patient undergoes major elective colorectal surgery. As part of the ERAS (Enhanced Recovery After Surgery) protocol, when should preoperative carbohydrate loading be given?
65. In damage control resuscitation for major haemorrhage following polytrauma, the concept of permissive hypotension targets which systolic blood pressure in patients WITHOUT traumatic brain injury?
66. In calculating parenteral nutrition requirements, the Harris-Benedict equation estimates basal metabolic rate (BMR). The BMR for a 70 kg, 175 cm, 40-year-old male using the Harris-Benedict equation is approximately:
67. In massive transfusion protocol (MTP), the current recommended ratio of packed red blood cells to fresh frozen plasma to platelets is:
68. According to ATLS classification of haemorrhagic shock, a patient with estimated blood loss of 1,500 mL (class III shock) would be expected to show which combination of clinical signs?
69. A post-operative patient on total parenteral nutrition (TPN) develops muscle weakness, paraesthesias, and respiratory failure. Serum phosphate is 0.4 mmol/L. This is characteristic of:
70. In massive blood transfusion (>10 units pRBC in 24 hours), the recommended ratio of packed red blood cells : fresh frozen plasma : platelets for damage control resuscitation is:
71. The SAFE (Saline versus Albumin Fluid Evaluation) trial compared 0.9% saline versus 4% albumin for ICU resuscitation. Which subgroup showed increased mortality with albumin compared to saline?
72. Refeeding syndrome is a potentially fatal electrolyte disorder occurring when nutrition is reintroduced to severely malnourished patients. The pathophysiology centers on a rapid fall in which electrolyte after refeeding begins?
73. In a patient requiring massive blood transfusion (>10 units pRBC in 24 hours), the current damage control resuscitation protocol recommends transfusing blood products in what ratio?
74. A post-operative patient in the ICU develops oliguria, hypotension, and a raised lactate of 5.2 mmol/L despite adequate volume resuscitation. He is septic with an intra-abdominal collection. The Surviving Sepsis Campaign recommends initial fluid resuscitation. Which fluid and target should be used for initial resuscitation in septic shock?
75. A surgical patient has Class III haemorrhagic shock according to ATLS classification. Which of the following BEST characterises this class?
76. The Caprini risk assessment model is used perioperatively. A 65-year-old man with BMI 35 kg/m², prior DVT, and undergoing a 3-hour major abdominal operation for colorectal cancer is assessed. Which VTE prophylaxis strategy is MOST appropriate?
77. A 45-year-old man undergoes a major bowel resection. He is started on total parenteral nutrition (TPN) via a central venous catheter. On day 3, he becomes confused, develops tetany, and ECG shows a prolonged QT interval. Serum phosphate is 0.4 mmol/L (low). The most likely diagnosis is:
78. A trauma patient receives massive transfusion (10 units pRBC in 6 hours). His ionized calcium is now 0.9 mmol/L (low). He develops hypotension with a widened QRS. The cause of hypocalcaemia in this context is:
79. A 55-year-old man in the ICU following a major hepatectomy has SIRS criteria met on day 2. Nutritional support is being planned. Enteral nutrition should be commenced within:
80. A 55-year-old man with Fournier's gangrene undergoes debridement and is admitted to ICU. He is sedated and ventilated. Enteral nutrition via a nasogastric tube is prescribed. If gastric residual volumes (GRVs) remain above 500 mL repeatedly, what is the recommended action per ESPEN/ASPEN 2022 guidelines?
81. A 40-year-old post-laparotomy patient has a serum sodium of 128 mEq/L on day 2. The resident plans aggressive sodium correction. The maximum safe rate of correction for symptomatic hyponatraemia to prevent osmotic demyelination syndrome (ODS) is:
82. In septic shock, which component of the Surviving Sepsis Campaign (SSC) Hour-1 Bundle (2018) must be completed FIRST before administering antibiotics?
83. A multiply-injured trauma patient receives a massive transfusion. The recommended ratio of packed red blood cells : fresh frozen plasma : platelets in current massive transfusion protocols (MTPs) based on PROPPR trial evidence is approximately:
84. A 35-year-old man in haemorrhagic shock following abdominal trauma receives massive transfusion. After 8 units of packed red blood cells, 8 units of fresh frozen plasma, and 1 unit of apheresis platelets, his ionised calcium is 0.85 mmol/L. What is the most likely cause and treatment?
85. A 60-year-old malnourished patient with oesophageal cancer requires nutritional supplementation before oesophagectomy. He weighs 55 kg with a BMI of 17. After initiating parenteral nutrition, on day 2 he develops muscle weakness, cardiac arrhythmia, and serum phosphate of 0.4 mmol/L. What complication has occurred?
86. Distributive shock is characterised by vasodilation and reduced SVR. In septic shock, the initial haemodynamic profile typically includes which combination?
87. A patient with septic shock on noradrenaline has persistent hypotension despite adequate fluid resuscitation. Random serum cortisol is 180 nmol/L with no increment after ACTH stimulation test. The diagnosis of relative adrenal insufficiency is made, and the treatment of choice is:
88. The SAFE study comparing albumin versus saline for fluid resuscitation showed that 4% albumin was associated with harm in which specific patient population?
89. In refeeding syndrome, which electrolyte abnormality is the hallmark metabolic derangement and the primary driver of cardiac arrhythmias?
90. The CALORIES trial compared parenteral nutrition (PN) versus enteral nutrition (EN) in critically ill adults in the first 5 days of ICU admission. The primary outcome (mortality at 30 days) showed:
91. The SAFE study compared albumin versus normal saline resuscitation in ICU patients. Which finding was specific to the traumatic brain injury subgroup?
92. In surgical patients requiring parenteral nutrition, the European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines recommend initiating early parenteral nutrition when oral/enteral nutrition cannot provide adequate intake, specifically when intake falls below what percentage of estimated energy requirement for more than 3 days?
93. Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related mortality. The current pathophysiological model implicates:
94. Damage control resuscitation (DCR) in massive hemorrhage employs a 1:1:1 ratio of packed red cells, fresh frozen plasma, and platelets. This strategy targets correction of which coagulopathy pattern seen in major trauma?
95. The NICE-SUGAR trial demonstrated that in critically ill ICU patients, intensive insulin therapy targeting glucose 4.5–6.0 mmol/L compared to conventional control (≤10 mmol/L) led to:
96. In massive transfusion protocol (MTP), the current evidence-based ratio of packed red blood cells : fresh frozen plasma : platelets is approximately:
97. Refeeding syndrome following aggressive nutritional support after prolonged starvation is characterised by which electrolyte abnormality as the hallmark?
98. In septic shock managed per Surviving Sepsis Campaign 2021 guidelines, the initial vasopressor of choice when MAP <65 mmHg despite adequate fluid resuscitation is:
99. A post-operative patient who has had a right hemicolectomy is being commenced on parenteral nutrition (TPN) on day 2. He is malnourished (serum phosphate 0.6 mmol/L, albumin 2.8 g/dL). Which complication is most likely to occur if TPN is started at full rate without caution?
100. A 60-year-old man on long-term anticoagulation with warfarin (INR 3.5) requires emergency appendicectomy. He is otherwise haemodynamically stable. The optimal strategy to reverse anticoagulation before surgery is:
101. A 45-year-old patient undergoes major abdominal surgery. On postoperative day 2, he develops oliguria (urine output 15 mL/hour), BP 90/60 mmHg, HR 115/min, and cold extremities. CVP is low (4 mmHg). What type of shock is this and what is the initial treatment?
102. A 30-year-old trauma patient has BP 80/60 mmHg, HR 140/min, estimated blood loss 2.5 L. He is conscious and anxious. According to the ATLS haemorrhagic shock classification, which class does he represent?
103. A surgeon is planning parenteral nutrition for a postoperative patient. Which of the following is the MOST common and serious metabolic complication of refeeding syndrome?
104. A patient in the surgical ICU develops acute haemolytic transfusion reaction 30 minutes after starting a blood transfusion. He develops fever, rigors, flank pain, and haemoglobinuria. What is the MOST critical immediate step?
105. A surgical patient is unable to tolerate enteral nutrition due to prolonged ileus post-bowel surgery. Parenteral nutrition is initiated. Which electrolyte complication is MOST characteristic of refeeding syndrome during nutritional support?
106. In neurogenic shock (due to high thoracic/cervical spinal cord injury), the haemodynamic profile is best characterised by:
107. The CRISTAL trial compared crystalloids versus colloids for ICU resuscitation. The main finding was:
108. Damage control surgery (DCS) for abdominal trauma involves an abbreviated initial operation followed by ICU resuscitation and planned re-look laparotomy. The physiological triad of lethal causes indicating DCS should be used ('lethal triad') consists of:
109. The NICE CG174 guideline for intravenous fluid therapy in adults recommends which assessment using the 5 Rs framework? Which of the following is NOT one of the 5 Rs?
110. A 55-year-old man in septic shock post-abdominal surgery has a MAP of 55 mmHg despite 3 L crystalloid. He is on noradrenaline 0.3 mcg/kg/min. His vasopressin level is expected to be low (vasopressin-deficient phase). According to the VANISH trial, adding vasopressin to noradrenaline in septic shock has which primary benefit?
111. A 68-year-old man undergoing major colorectal surgery per Enhanced Recovery After Surgery (ERAS) protocol receives goal-directed intraoperative fluid therapy. Which intraoperative haemodynamic target best reduces postoperative complications in colorectal ERAS programmes?