The Addition of Mechanical Insufflation/Exsufflation Shortens Airway-Clearance Sessions in Neuromuscular Patients With Chest Infection

BACKGROUND: Mechanical insufflation/exsufflation (in-exsufflation) increases peak cough flow and may improve sputum clearance. No studies have compared current respiratory physiotherapy practice (manual percussion, shaking, and assisted cough) plus mechanical in-exsufflation to current physiotherapy practice without in-exsufflation in noninvasive-ventilation (NIV) dependent neuromuscular patients with an acute respiratory-tract infection. We hypothesized that airway clearance in these patients would be more effective with in-exsufflation, compared to without in-exsufflation.

METHODS: Eight patients (6 male), median age 21.5 y (range 4-44 y). All had sputum retention, with an elevated C-reactive protein of 113 mg/L (range 13-231 mg/L) and a white-cell count of 14}10⁹ cells/L (range 7-25}10⁹ cells/L). Patients underwent a 2-day randomized crossover treatment program, with in-exsufflation for one session and without in-exsufflation for the second, with a reverse-crossover on the next day. Treatment time after 30 min (or earlier if sputum clearance was complete) was recorded. Outcome measures were heart rate, pulse oximetry (S_pO2), transcutaneous carbon dioxide tension (P_tcCO2), and independently assessed auscultation score. Patients rated effectiveness on a visual analog scale.

RESULTS: Treatment time after 30 min was significantly shorter with in-exsufflation, versus without in-exsufflation session (30 + 0 = 30 min (range 0-26 min) vs 30 + 17 = 47 min (range 0-35 min) (P = .03). There was a significant improvement in auscultation score in both groups (with in-exsufflation 2.9 ± 1.9 to 1.8 ± 2.0, P = .02; without in-exsufflation 3.4 ± 2.0 to 2.3 ± 2.2, P = .007). Visual-analog-scale score for the amount of sputum cleared in both treatment groups showed a decline (P < .05). There was no difference in mean heart rate, S_pO2, or P_tcCO2 with either treatment.

CONCLUSIONS: This is a short-term study of the use of in-exsufflation as a supplement to standard NIV plus physiotherapy in a small group of patients with neuromuscular disease. The addition of mechanical in-exsufflation shortened airway-clearance sessions. The device appeared to be safe and well tolerated, and may provide additional benefit to patients with neuromuscular disease and upper-respiratory-tract infection; further studies are indicated.