Delayed Emergence Due to Severe Respiratory Acidosis Following Prolonged Spine Surgery: A Case Report.

Delayed emergence from anesthesia is a frequent challenge in surgical settings. Common etiologies include residual drug effects, metabolic derangements, or neurological insults. We report a case of a 55-year-old woman who underwent an elective six-hour lumbar laminectomy and cervical implantation surgery. Despite an uneventful intraoperative course and routine neuromuscular blockade reversal, the patient exhibited somnolence and ventilatory failure after reversal and extubation. Arterial blood gas (ABG) analysis revealed severe respiratory acidosis. The patient required re-intubation and controlled mechanical ventilation to facilitate carbon dioxide (CO₂) washout. Following normalization of arterial partial pressure of carbon dioxide (PaCO₂), the patient regained consciousness and was successfully extubated the following morning. This case highlights the importance of monitoring ventilation adequacy in the transition from controlled to spontaneous respiration following long-duration surgeries. Importantly, normal intraoperative end-tidal CO₂ values should not be considered reassuring in high-risk patients, as significant arterial hypercapnia may remain undetected.