Effect of body position on peak expiratory flow during mechanical insufflation–exsufflation in people with cervical spinal cord injury: a pilot study

This prospective pilot study investigated the influence of body position on peak cough flow (PCF) during mechanical insufflation–exsufflation (MI-E) treatment in people with tetraplegia. Fifteen participants with cervical spinal cord injury (C-SCI) were randomized into two groups, which differed in the starting position, that is, the patients were either supine or reclined. Four sessions of MI-E in alternating positions with each session comprising three different maneuvers: five voluntary coughs, five MI-E-assisted coughs, and five MI-E-assisted with manual thrusts were performed with continuous airflow measurement reporting PCF from every cough. PCF was associated with the application maneuvers, total insufflation volume (TIV), and interaction between position and maneuvers but not with the application position. The estimated mean PCF was 1.808, 3.529, and 3.925 L/s when supine and 1.672, 3.598, and 3.909 L/s when reclined from voluntary cough, MI-E, and MI-E with manual thrust, respectively. The estimated PCF change compared to voluntary cough was 1.721 (95% CI, 1.603–1.838) L/s from the combined MI-E and 2.116 (95% CI, 2.005–2.228) L/s from the MI-E with manual thrust, calculated from the linear mixed-model analysis. PCF moderately correlated with TIV (R(2) = 0.64). Therefore, either position can be used for C-SCI patients as long as MI-E can be performed with manual thrust and sufficient TIV is provided.