Perioperative Fluid, Electrolyte and Acid-Base Management MCQs

Anaesthesia · 18 free questions with answers & explanations.

1. A 70 kg adult male undergoes a 4-hour laparoscopic colectomy. Using the ERAS-endorsed goal-directed fluid therapy concept, which approach best characterises optimal intraoperative fluid management?
2. Arterial blood gas of a post-operative patient: pH 7.28, PaCO2 48 mmHg, HCO3 21 mEq/L, Na 138, Cl 115, albumin 2.2 g/dL. What is the PRIMARY acid-base disorder?
3. A patient in ICU after major hepatic resection has serum Na 118 mEq/L and is asymptomatic. The rate of correction of hyponatraemia must not exceed which limit to prevent osmotic demyelination syndrome (ODS)?
4. Which crystalloid solution is MOST appropriate as a maintenance fluid in a patient who has undergone a 3-hour open abdominal surgery and remains intubated in the ICU with normal renal function and no electrolyte abnormalities?
5. Intraoperative Stewart's strong ion difference (SID) approach to acid-base: a patient receives 3 litres of 0.9% NaCl. Which change in SID correctly explains the resultant acidosis?
6. A 70 kg patient undergoing a 4-hour laparotomy has received 4 litres of 0.9% saline intraoperatively. Postoperatively, ABG shows pH 7.28, PaCO2 38 mmHg, HCO3 17 mEq/L, Na+ 140, Cl- 116 mEq/L. What is the PRIMARY cause of this acid-base disturbance?
7. During major vascular surgery, a patient develops serum potassium of 6.8 mEq/L with peaked T waves on ECG. Which intervention has the FASTEST onset to stabilise the cardiac membrane?
8. A 35-year-old patient undergoing elective knee arthroscopy is found to have serum sodium of 123 mEq/L preoperatively. She has been drinking 4–5 litres of water daily. What is the MOST likely diagnosis and the recommended rate of sodium correction?
9. Goal-directed fluid therapy (GDFT) during major abdominal surgery uses which parameter MOST reliably to predict fluid responsiveness in mechanically ventilated patients?
10. A 70 kg patient undergoing open abdominal aortic aneurysm repair (estimated 3 hours) receives 4.2 L of normal saline (0.9% NaCl) intraoperatively. Postoperatively his arterial blood gas shows pH 7.28, PaCO₂ 38 mmHg, HCO₃⁻ 17 mEq/L, Cl⁻ 115 mEq/L. The acid-base disorder is:
11. In goal-directed fluid therapy (GDT) for major abdominal surgery, which haemodynamic variable is the most reliable dynamic predictor of fluid responsiveness in a mechanically ventilated patient?
12. A trauma patient's blood gas shows: pH 7.18, PaCO₂ 32 mmHg, HCO₃⁻ 11 mEq/L, Na⁺ 138, Cl⁻ 100, lactate 8.2 mmol/L. What is the primary acid-base disorder and its expected compensation?
13. During laparoscopic surgery a patient develops a sudden rise in end-tidal CO₂ to 62 mmHg with haemodynamic instability. After ruling out CO₂ embolism, what is the next most likely cause of hypercarbia?
14. Which crystalloid solution is most appropriate for the resuscitation of a patient with traumatic brain injury (TBI) and hypotension, given both haemodynamic and neurological considerations?
15. A 70 kg patient undergoing a 4-hour laparotomy receives 3 L of normal saline. Postoperative ABG shows pH 7.28, PaCO2 38 mmHg, HCO3 18 mEq/L, Na 138 mEq/L, Cl 116 mEq/L. What is the primary acid-base disturbance?
16. A 50 kg woman undergoing elective surgery receives IV fluids for preoperative fasting replacement. Using the Holliday-Segar '4-2-1' rule, what is the maintenance fluid rate (mL/h) for a 50 kg adult?
17. Which of the following colloids is MOST associated with acute kidney injury in septic patients and is no longer recommended for volume resuscitation in sepsis?
18. Goal-directed fluid therapy (GDT) in major abdominal surgery uses dynamic parameters to guide fluid administration. Which parameter is MOST reliable in a mechanically ventilated patient with regular sinus rhythm?