This study was undertaken to test the hypothesis that a tracheal tube occlusion protocol predicts clinically important obstruction to air flow in patients requiring prolonged mechanical ventilation, making routine bronchoscopy unnecessary.
A prospective evaluation of 75 patients who were clinically ready to be decannulated. All patients underwent the tracheal tube occlusion protocol followed by bronchoscopy.
Three hospitals affiliated with a college of medicine.
Over a 24-month period, 52 males and 23 females were enrolled in the study. Mean age was 55 yrs (range 25 to 85). Mean endotracheal/tracheostomy time was 2.4/8.9 wks (range 1 to 4/5 to 14). All patients were mechanically ventilated for at least 4 wks and were successfully weaned from the mechanical ventilator for at least 48 hrs. During spontaneous breathing, these data were observed: minute ventilation of <10 L/min; resting respiratory rate of <18 breaths/min; and arterial oxygen saturation of >90% on 40% oxygen tracheal collar mask. The tracheal tube occlusion protocol consisted of deflating the cuff on the fenestrated tracheal tube and occluding the tube.
Patients who developed respiratory distress when the tracheal tube was occluded were deemed to have failed the protocol. At bronchoscopy, the patients were asked to cough and hyperventilate in an attempt to forcibly reduce the cross-sectional area of the trachea. A sustained, subjectively assessed decrease of >or=to50% of the effective cross-sectional area of the trachea was considered to be an indication for intervention.
Measurements and Main Results
Sixty-three (84%) of 75 patients tolerated the tracheal tube occlusion protocol. Twelve (16%) of 75 patients developed signs of respiratory distress and showed decreased oxygen saturation values necessitating uncapping of the tracheal tube. All patients had some degree of tracheal injury. However, those patients who failed to tolerate the tracheal tube occlusion protocol had clinically important tracheal obstruction to air flow.
A tracheal tube occlusion protocol can predict clinically important obstruction to air flow after prolonged mechanical ventilation. (Crit Care Med 1997; 25:413-417)