Post-extubation pulmonary function tests in detection of upper airway obstruction in drug-overdosed patients

A relatively high percentage of hypnotic-sedative drug-overdosed (HSDO) patients suffer post-extubation upper airway obstruction. Since early detection and treatment of these lesions is desirable, we studied 20 recently extubated (within 24 hours) as well as 11 non-intubated HSDO patients employing flow-volume loops and spirometry. Abnormalities in tests for upper airway obstruction were common in both groups but only in the four post-extubation patients with clinically suspected upper airway obstruction was an inspiratory plateau by flow volume loops found. In addition, three of these four patients had mid-VC ratios greater than 1.25. We conclude that the Inspiratory flow volume loop and the mid-VC ratio may help in detecting post-extubation upper airway obstruction in lethargic, HSDO patients.