Abrupt Collapse at Insufflation During Laparoscopic Cholecystectomy

Most likely: venous gas embolism (CO2) - the timing with insufflation and the abrupt fall in end-tidal CO2 are the signature.

Reasoning from the data:

• EtCO2 falls because pulmonary blood flow falls. Gas in the right heart and pulmonary circulation obstructs outflow, dead space rises sharply, and the lung excretes less CO2. The low, normal-shaped plateau tells you ventilation is still occurring - this is a perfusion problem, not an airway problem.
• Anaphylaxis is the main competitor (cefazolin, rocuronium). It also lowers EtCO2 and BP, but typically produces bronchospasm (peak pressure would climb well above 24 cmH2O), wheeze, urticaria, and onset over minutes rather than seconds. Equal breath sounds and no wheeze argue against it.
• Tension pneumothorax or pneumopericardium would raise peak pressure substantially and usually cause asymmetry.
• Hemorrhage lowers BP and EtCO2 but not within seconds of insufflation, and SpO2 usually holds until late.
• Circuit disconnection or leak drops EtCO2 and SpO2 but peak pressure would fall, not rise.

A mill-wheel murmur or a precordial Doppler change would support embolism, but both are insensitive and neither is required to act.

1. Say the word out loud and stop the insufflation. Ask the surgeon to desufflate immediately - reducing intracavitary pressure reduces further gas entry.
2. 100% oxygen and stop nitrous oxide if it is running. Nitrous oxide diffuses into gas-containing spaces and enlarges the embolus; oxygen also treats the hypoxia.
3. Position head-down, left lateral decubitus (Durant position). This keeps gas in the right ventricular apex away from the outflow tract, allowing it to be propelled forward rather than obstructing.
4. Support the circulation: rapid crystalloid bolus, and phenylephrine or norepinephrine for the vasodilation and right-heart failure. Escalate early rather than waiting.
5. Aspirate from a central line if one is in place with its tip near the superior vena cava/right atrial junction - this can retrieve gas. Do not delay resuscitation to place a line.
6. Reassess the differential: if peak pressure is climbing and wheeze appears, treat anaphylaxis (epinephrine, fluids, stop the trigger). If she arrests, standard ACLS with early consideration of the embolus as the cause.

Send an ABG. Remember that EtCO2 now underestimates PaCO2, so trust the blood gas, not the number on the monitor.

Lower pressure is not a fix. A clinically significant embolism means gas entered the venous circulation under pressure; the risk of a second, larger embolus during further insufflation is real, and CO2 emboli can recur even though CO2 is more soluble than air. The judgment is not whether 8 mmHg is "safer" than 15 - it is whether the remaining benefit of finishing laparoscopically justifies re-exposing her.

A defensible answer: allow the surgeon to complete only the essential parts of the procedure (or convert to open) at the lowest pressure that gives adequate exposure, with continuous monitoring and a low threshold to abandon the pneumoperitoneum. Do not permit re-insufflation if she becomes unstable again.

Before the case ends:

• Document the event, timing, and response in the anesthetic record.
• Decide the destination deliberately: this patient needs a monitored setting, not a phase-1 discharge. She had hypoxia and hypotension; postoperative respiratory failure and delayed arrhythmias occur.
• If a central line was placed, confirm position on imaging before use for vasopressors.
• Debrief with the team so that the next insufflation is treated with the same respect.