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AS6.1-3 | Post-anaesthesia Recovery — PBL Case

CLINICAL SETTING

Mr Ramesh Kumar, a 48-year-old software engineer with a BMI of 32 and a history of obstructive sleep apnoea (OSA) managed with CPAP at home, is transferred to the PACU at 14:30 following laparoscopic Nissen fundoplication under general anaesthesia. The procedure lasted 2 hours 45 minutes. His intraoperative anaesthetic included propofol 2 mg/kg for induction, rocuronium 0.9 mg/kg, sevoflurane maintenance, and a total of fentanyl 300 mcg given in incremental doses. Neostigmine 2.5 mg and glycopyrrolate 0.5 mg were given for reversal of neuromuscular blockade 15 minutes before extubation. He was extubated in the operating theatre and transferred breathing spontaneously on a non-rebreather mask. On arrival to the PACU at 14:35, the handover nurse documents: GCS 14 (E3V4M5), SpO2 91% on 10 L/min non-rebreather mask, RR 10/min, HR 88/min, BP 122/74 mmHg, temperature 35.8°C. The nursing staff note he is making partial snoring sounds when supine. Jaw thrust improves his SpO2 to 96%. His Aldrete score at arrival is 7/10.

Trigger 1: Deteriorating Oxygenation Despite Supplemental Oxygen

At 14:55 (20 minutes after PACU arrival), SpO2 drops to 86% despite continued non-rebreather mask at 10 L/min. RR is now 7/min. Mr Kumar's GCS has fallen to 12 (E3V3M5). He has pinpoint pupils. HR is 76/min and BP is 116/70 mmHg. A nasopharyngeal airway (NPA) is inserted and provides only partial improvement. The nursing staff note that he received the last dose of fentanyl 100 mcg intraoperatively at 14:05 — approximately 90 minutes ago.

DISCUSSION POINTS

What is the most likely primary cause of Mr Kumar's deteriorating respiratory status at this point? What features support this diagnosis over other differentials (airway obstruction alone, bronchospasm, aspiration)?
The nursing staff have naloxone 0.4 mg ampoules available. A colleague suggests giving 0.4 mg as a rapid IV bolus. What are the potential harms of this approach, and what is the correct dosing strategy for this situation?

Click to reveal Trigger 2: Haemodynamic Change and Incomplete Response to Naloxone (discuss previous trigger first!)

Trigger 2: Haemodynamic Change and Incomplete Response to Naloxone

Naloxone 0.1 mg IV is administered at 15:00. At 15:05, SpO2 has improved to 93% on non-rebreather mask and RR is 12/min, but Mr Kumar remains drowsy (GCS 13). His BP is now 145/92 mmHg and HR is 104/min. He is complaining of severe abdominal pain (VAS 8/10) and is agitated. At 15:10, SpO2 drops again to 89% — suggesting the naloxone effect is waning. The recovery nurse also notes that during the fall in oxygen saturation at 14:55, the crash cart was wheeled to the bedside. She opens it to prepare further naloxone and notices the defibrillator pads are present but the 20% intralipid vials are missing from the crash cart.

DISCUSSION POINTS

Why does Mr Kumar's SpO2 drop again at 15:10, and what does this tell you about the pharmacokinetics of naloxone versus fentanyl? What is the appropriate response to recurrent OIRD after initial naloxone dosing?
The 20% intralipid is missing from the crash cart. For which specific PACU emergency is intralipid the designated antidote, and what pharmacological principle underlies its use? What does this finding tell you about crash cart checking standards in this PACU?

Click to reveal Trigger 3: New Hypotension and Wound Assessment (discuss previous trigger first!)

Trigger 3: New Hypotension and Wound Assessment

By 15:30, Mr Kumar's respiratory function has stabilised after two further naloxone doses (total 0.4 mg administered incrementally over 30 minutes). SpO2 is 95% on 6 L/min nasal cannula, RR 14/min, GCS 15. However, a new problem emerges: BP drops to 88/54 mmHg and HR rises to 122/min. He appears pale and anxious. His abdomen is tender. Temperature is 35.4°C. His IV fluid balance shows only 600 mL of crystalloid given intraoperatively. The surgical wound appears intact externally. The anaesthetist reviews Mr Kumar and suspects possible intra-abdominal bleeding from a port site vessel. Simultaneously, a nursing student asks whether this hypotension could be a delayed effect of the spinal component — the anaesthetist replies there was no spinal block in this case.

DISCUSSION POINTS

Compare the haemodynamic profile of haemorrhagic shock (as suspected here) with the profile of residual spinal sympathectomy. How does distinguishing between them change immediate management?
Drawing on all three competencies (AS6.1, AS6.2, AS6.3), construct a prioritised PACU response plan for Mr Kumar at 15:30. Which members of the team must be contacted, what monitoring changes are required, what must be checked on the crash cart, and what investigations are immediately needed?

Group Task Assignments

Group 1: Collaborative Task

As a group, design a 'PACU Handover Checklist' for a post-general-anaesthesia patient with OSA and high intraoperative opioid exposure. Include: transfer criteria from OT, minimum monitoring standards on PACU arrival, documentation requirements for opioid doses received, and pre-discharge oxygenation criteria. Reference the modified Aldrete score and specify which Aldrete score threshold triggers mandatory anaesthetist review.

Group 2: Collaborative Task

Prepare a five-minute briefing for a newly recruited PACU nurse covering the three scenarios where calling the anaesthetist immediately is non-negotiable: (1) airway emergencies, (2) haemodynamic instability unresponsive to initial measures, and (3) recurrent OIRD. For each scenario, define the one clinical sign that is the most sensitive early warning and the first nurse-led action that must begin before the anaesthetist arrives.

Learning Issues

Research these questions and bring your findings to the discussion.

[AS6.1] What are the principles of structured monitoring in the PACU — what parameters are monitored, at what frequency, using which tools (including the modified Aldrete score), and how do transfer criteria from OT to PACU differ from PACU-to-ward discharge criteria?
[AS6.2] What are the mandatory contents of the PACU crash cart — which airway devices, resuscitation drugs (with doses), and emergency reversal agents (including 20% intralipid) must be present, and what is the standard for frequency and documentation of crash cart checks?
[AS6.3] What are the five most common PACU complications (upper airway obstruction, OIRD, laryngospasm, post-operative hypotension, post-operative nausea/vomiting), and for each: what are the recognition criteria, the initial nurse-led interventions, and the indications for anaesthetist involvement?