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Question: Critical Care

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You are sedating a 16 year old boy with past medical history of spontaneously resolved VSD as an infant with ketamine for tube thoracostomy to treat a spontaneous pneumothorax. Before the tube thoracostomy procedure can begin, the patient has a sudden episode of oxygen desaturation, lack of end-tidal CO2 waveform, and gurgling noises. It successfully resolves after a couple of minutes of bag-valve-mask ventilation, and the practitioners prepare to begin the procedure again. However, immediately thereafter the patient begins to cough up pink frothy secretions and to desaturate again, although the end-tidal CO2 waveform does not change this time. 

What is the most likely cause of this patient’s deterioration?

pemsou5_wp • January 12, 2021

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  1. Kelly January 13, 2021 - 12:49 am Reply

    A) Negative-pressure pulmonary edema
    The initial event described is consistent with laryngospasm, a rare complication of ketamine procedural sedation. During the laryngospasm episode, the patient’s attempts to inspire against a closed glottis generated high negative intrathoracic pressures, which can lead to sudden onset “flash” pulmonary edema. Rapid reexpansion of a collapsed lung can cause pulmonary edema, but usually presents over hours. The distant history of VSD resolution is unlikely to cause cardiogenic pulmonary edema, and this would not present suddenly either. Ketamine is not particularly associated with pulmonary edema. The presentation is less consistent with pulmonary embolism and the patient does not have stated risk factors.

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