CC BY-NC-ND 4.0 · J Neuroanaesth Crit Care
DOI: 10.1055/s-0042-1744403

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

Amy H. S. Kong
1   Department of Anaesthesiology and Operating Theatre Services, Kwong Wah Hospital, Hong Kong
Peter Y. M. Woo
2   Department of Neurosurgery, Kwong Wah Hospital, Hong Kong
Wilson M. Y. Choo
1   Department of Anaesthesiology and Operating Theatre Services, Kwong Wah Hospital, Hong Kong
Desiree K. K. Wong
2   Department of Neurosurgery, Kwong Wah Hospital, Hong Kong
› Author Affiliations

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 10 minutes after bone flap removal, the patient coughed briefly followed by a transient drop in SpO2 to 78% and end tidal CO2 (EtCO2) to 1.7 kPa. Because her SpO2 and EtCO2 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.

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Fig. 1 Intraoperative vitals.

Sixty minutes later, during brain mapping, a gradual decline in SpO2 to 92% was observed with no reduction in EtCO2. The patient remained asymptomatic with no clinical seizures and no epileptogenic activity noted during electrocorticography.

Toward the end of tumor resection, a second precipitous drop in SpO2 to 80% associated with tachypnea occurred. The patient remained conscious and denied any chest pain. Chest auscultation revealed bilateral expiratory wheezing. Despite increasing her oxygen supplementation and administering salbutamol, her SpO2 further decreased to 70%. Her SpO2 improved to 90% only when 100% oxygen was delivered via a non-rebreathing mask. Her arterial blood gas (FiO2: 1.0) showed that the PaO2 and PaCO2 levels were 7.7 kPa and 5.05 kPa, respectively. This episode was accompanied by transient hypotension (SBP: 80 mmHg) that responded to intravenous crystalloid bolus infusion. Intraoperatively, 1700 mL of crystalloids was administered with an urine output of 1200 mL over 6 hours and blood loss of 200 mL.

The operation was rapidly completed after this latest third episode of oxygen desaturation. A postoperative ECG showed normal sinus rhythm without acute changes. Transthoracic echocardiography showed an undilated right ventricle with a collapsed inferior vena cava, reflecting the absence of pulmonary hypertension. A chest X-ray ([Fig. 2]) showed diffuse pulmonary infiltrates. Her serum troponin T level was slightly elevated (41 ng/L) and was normalized within 24 hours. An urgent CT pulmonary angiogram ([Fig. 2]) showed diffuse pulmonary edema and bilateral pleural effusion without evidence of arterial embolism.

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Fig. 2 CXR and CT angiogram.

Postoperatively, the patient experienced full recovery with only supportive management, i.e., oxygen supplementation and chest physiotherapy, and was discharged home 8 days later.

Publication History

Article published online:
05 May 2022

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