Acute Pulmonary Edema with Paradoxical Desaturation after Salbutamol due to Venous Air Embolism during an Awake Craniotomy: A Diagnostic Challenge

A 75-year-old non-smoker with good past health underwent an awake craniotomy for motor mapping and glioblastoma resection. During the procedure, she was sedated by intravenous propofol and remifentanil using target-controlled infusion (TCI) with bispectral index monitoring (target: 70–80). The effect-site drug concentrations were titrated between 1 and 2 µg/mL and 0 to 1 ng/mL, respectively. The patient was placed in a semi-sitting position (30-degree head up). The patient’s systolic blood pressure dropped slightly after the start of sedation; her other vital signs remained normal ( ►Fig. 1 ). Within 10minutes after bone flap removal, the patient coughed briefly followed by a transient drop in SpO 2 to 78% and end tidal CO 2 (EtCO 2 ) to 1.7 kPa. Because her SpO 2 and EtCO 2 promptly improved after applying jaw thrust and nasopharyngeal airway, this episode was attributed to deep sedation. Sedation was stopped and the patient was asymptomatic after regaining consciousness. Sixty minutes later, during brain mapping, a gradual decline in SpO 2 to 92% was observed with no reduction in EtCO 2 . The patient remained asymptomatic with no clinical seizures and no epileptogenic activity noted during electrocorticography.