Post-operative Day 2: Delirium or Sepsis?
Mr A is 68 and on post-operative day 2 after a right hemicolectomy (converted from laparoscopic to open) for colon cancer. His history includes type 2 diabetes, hypertension and an ejection fraction of 35%. At 06:40 the night nurse reports he 'seems off'. You find him oriented to person only, restless, and pulling at his IV line. Vital signs: temperature 38.4 °C, heart rate 118 in sinus rhythm, respiratory rate 24, blood pressure 98/56 mmHg (his baseline is 136/78), SpO2 93% on room air. Urine output over the last 3 hours totals 55 mL via urinary catheter. The abdomen is distended and tender in the right lower quadrant; the midline incision is intact with 2 cm of surrounding erythema and no drainage. Capillary refill is 3 seconds and his lips are dry. Point-of-care lactate is 3.6 mmol/L, glucose 15.2 mmol/L, white cell count 16.2 × 10⁹/L. The surgical registrar, by telephone, says it is 'post-operative delirium - give melatonin and recheck in the morning'.
1. State your working interpretation of this change in condition and identify which findings carry the most diagnostic weight. Name at least two alternatives you considered and explain why you set them aside.
Read the worked answer
This is sepsis with a probable intra-abdominal source until proven otherwise, with delirium as a symptom rather than the diagnosis.
Weight-bearing findings
- Trajectory, not single numbers: BP 98/56 against a personal baseline of 136/78 is a 38 mmHg systolic fall; urine 55 mL in 3 hours (≈18 mL/h) in a catheterised patient is objective oliguria.
- qSOFA 3/3: respiratory rate ≥22, altered mentation, systolic BP ≤100.
- Lactate 3.6 mmol/L with fever 38.4 °C and white cells 16.2 indicates hypoperfusion plus infection.
- Capillary refill 3 s, dry mucosa: hypovolaemia is present but does not explain fever or leucocytosis.
- Wound erythema plus distension and right lower quadrant tenderness: the anastomosis and deep space are the likeliest source, not the skin.
Alternatives
- Anaesthetic/opioid delirium: possible contributor, but delirium alone does not produce fever, lactate 3.6 and oliguria.
- Simple hypovolaemia/third-space loss: contributes, but does not account for the inflammatory picture.
- Hyperglycaemic decompensation: glucose 15.2 matters, but there is no evidence of ketosis and it does not explain fever.
- Pulmonary embolism: tachycardia and mild hypoxia fit, but fever and leucocytosis do not.
The registrar's framing is unsafe because it treats a reversible, time-critical deterioration as a comfort problem. Anastomotic leak is the diagnosis that must be excluded in the next hour, not the next morning.
2. The registrar plans to wait until morning. Set out your actions and escalation over the next 60 minutes, including what you would say on the telephone and how his ejection fraction of 35% changes your fluid plan.
Read the worked answer
Telephone escalation (state facts, name the risk, name the deadline) 'I am calling about Mr A, bed 12, day 2 after hemicolectomy. He has new confusion, temperature 38.4, heart rate 118, BP 98/56 from a baseline of 136/78, respiratory rate 24, 55 mL of urine in 3 hours and lactate 3.6. He meets sepsis criteria with a likely intra-abdominal source. I need him reviewed at the bedside within 30 minutes. If you cannot attend, I will call the consultant surgeon on call and activate the rapid response team. Which antibiotics do you want, and may I take cultures now?'
Actions before the call
- Full set of observations, repeat lactate, capillary glucose, ECG, two large-bore cannulae.
- Blood cultures from two sites (and urine, wound if draining) before antibiotics, without delaying them.
- FBC, urea and electrolytes, liver function, coagulation, venous blood gas, group and save.
- Oxygen only if SpO2 <94%; head-up positioning; hourly urine measurement.
Fluids with an ejection fraction of 35% An ejection fraction of 35% is not a reason to withhold resuscitation; it is a reason to titrate. Give balanced crystalloid in 250–500 mL increments over 15–30 minutes and reassess after each: blood pressure, heart rate, lung sounds, SpO2, capillary refill, urine output. Escalate to vasopressor support and critical care involvement early if mean arterial pressure stays below 65 mmHg despite the first 500–1000 mL, rather than stacking large volumes. Request an early echocardiogram and consider brain natriuretic peptide.
3. Write the reassessment schedule you would institute for the next two hours and the specific triggers that should activate the rapid response team.
Read the worked answer
Reassessment schedule
- Observations (including level of consciousness and respiratory rate counted for a full 60 seconds) every 15 minutes for the first hour, then every 30 minutes if no deterioration and the plan is accepted by the surgical team.
- Hourly urine output with a urometer; flag anything under 30 mL/h for two consecutive hours.
- Lactate repeat at 2–4 hours; a falling lactate is the best early confirmation that resuscitation is working.
- Capillary glucose hourly while hyperglycaemic, aiming for 8–10 mmol/L with the insulin protocol.
- Repeat white cell count and cultures at 48–72 hours; daily review of wound and drain output.
- Pain score and sedation review before each dose of opioid, so that analgesia does not re-mask the mental state.
Rapid response triggers (any one)
- Systolic BP below 90 mmHg, or a fall of more than 40 mmHg from baseline, or mean arterial pressure below 65 mmHg.
- Heart rate above 120 sustained for more than 10 minutes, or new arrhythmia.
- Respiratory rate above 28 or below 8, or SpO2 below 90% on 2 L/min.
- Urine output below 30 mL/h for two hours.
- A further drop in consciousness of 2 or more Glasgow Coma Scale points, or a rising lactate on repeat.
The reasoning is to convert a subjective 'seems off' into a quantified trend that cannot be deferred. Document every escalation, including the time of the call, the name of the clinician and the response, because the clinical record is what demonstrates that the nurse recognised and acted on deterioration.