Capnogram plateau micro‑oscillations preceding end‑tidal CO2 decline as an early cue to venous air embolism during supratentorial craniotomy: a case report.

BACKGROUND

Venous air embolism (VAE) is a potentially fatal complication of craniotomy. When a TEE is not used, attention to waveform-level changes during conventional monitoring is crucial. CASE PRESENTATION: A woman in her 70 s underwent supratentorial tumor resection in the supine position with a slight head-up tilt. Approximately 1 h after the craniotomy, gradual decreases in SpO2 (98% → 96%), systolic blood pressure (105 → 90 mmHg), and EtCO2 (37 → 30 mmHg) were observed. New micro-oscillations appeared on the capnogram plateau, followed by an EtCO2 decrease to 22 mm Hg. VAE was suspected. Treatment, including field flooding, head-down positioning, as well as FiO2, dobutamine, and rapid fluid supplementation, stabilized her and allowed the uneventful completion of surgery. Arterial blood gas levels improved concurrently with EtCO2 recovery.

CONCLUSIONS

Careful scrutiny of capnogram morphology, not only numeric EtCO2, can expedite the suspicion and timely management of VAE when advanced monitoring is unavailable.