Delayed emergence after general anesthesia: working through the differential diagnosis

Delayed emergence (DE) following general anesthesia is a critical postoperative complication characterized by the patient's inability to regain an appropriate level of consciousness 30-60 minutes after surgery. Rapid identification and management of potential causes, including metabolic disturbances and pharmacologic effects, are essential to prevent adverse outcomes.

We present the case of a 67-year-old female with multiple comorbidities, including chronic obstructive pulmonary disease, hemochromatosis, and hypothyroidism, who underwent emergent exploratory laparoscopy for a pelvic abscess. Despite uneventful hemodynamic stability and appropriate anesthetic management, the patient experienced delayed emergence. Initial interventions included reversal agents for neuromuscular blockade and opioids; however, the patient's mental status continued to fluctuate. Arterial blood gas analysis revealed hypercapnic respiratory metabolic acidosis, prompting ventilatory support and subsequent reintubation. Neurovascular events were ruled out with unremarkable imaging findings.

Delayed emergence can result from a variety of etiologies, including residual anesthetic effects, metabolic imbalances, and neurologic events. This case highlights the importance of prompt identification of hypercapnic respiratory metabolic acidosis as a reversible cause of DE. Management included ventilatory support with bilevel positive airway pressure and subsequent intubation, which resolved the acidosis and restored consciousness.

This case underscores the need for a systematic approach in the differential diagnosis of delayed emergence. Timely recognition and management of hypercapnic respiratory metabolic acidosis through ventilatory support were crucial in preventing further complications.