Study objectives: To analyze the physiologic effects and tolerance of mechanical insufflation-exsufflation (MI-E) for patients with chronic ventilatory failure of various etiologies.
Design: Prospective clinical trial.
Setting: Rehabilitation unit of a university hospital.
Patients or participants: Thirteen patients with amyotrophic lateral sclerosis (ALS), 9 patients with severe COPD, and 7 patients with other neuromuscular disorders (oNMDs) with chronic airway secretion encumbrance and decreases in oxyhemoglobin saturation (Spo2).
Interventions: Pressures of MI-E of 15 cm H2O, 30 cm H2O, and 40 cm H2O were cycled to each patient, with 3 s for insufflation and 4 s for exsufflation. One application was six cycles at each pressure for a total of three applications.
Measurements and results: We continuously evaluated respiratory inductance plethysmography (RIP) and Spo2 during every application. Peak cough flow (PCF) and dyspnea (Borg Scale) were also measured before the first and after the last application. The technique was well tolerated in all patient groups. Median Spo2 improved significantly (p < 0.005) in all patient groups. Median PCF improved significantly (p < 0.005) in the ALS and oNMD groups from 170 to 200 L/min and from 180 to 220 L/min, respectively, and dyspnea improved significantly in the patients with oNMDs and patients with COPD from 3 to 1 and from 2 to 0.75, respectively. Breathing pattern characteristics (RIP) did not deteriorate after MI-E in any patient groups. Inspiratory flow limitation significantly decreased at the highest MI-E pressures for the ALS group.
Conclusions: Our results confirm good tolerance and physiologic improvement in patients with restrictive disease and in patients with obstructive disease, suggesting that MI-E may be a potential complement to noninvasive ventilation for a wide variety of patient groups.