The Flow-Pressure and Cardiopulmonary Responses of Manual Chest Percussion with Different Ranges of Oscillation Frequency in Healthy Subjects

Manual chest wall percussion (MP) is a technique for secretion clearance which commonly use. However, MP is performed by physiotherapists throughout a broad range of the oscillation frequency, which might result in different physical properties and cardiopulmonary responses of MP. Investigate the flow, pressure and cardiorespiratory response during MP with 3 frequencies in healthy subjects. Twenty-one healthy subjects (8 men and 13 women) were recruited into this crossover study. MP was applied with 3 frequency ranges, including low (4.0 ± 0.5), medium (5.5 ± 0.5), and high (6.5 ± 0.5) Hz, for 3 min in the neutral side lying on left side. A flow sensor (Model SS11LA) and a pressure sensor (Model SS13L) were used to measure Inspiratory-expiratory (I-E) flow rate and pressure through mouth. A bedside monitor (BSM 2351k, Nihon Kohden) was used to measure cardiopulmonary response. All dependent variables were measured pre- (resting), during, and post- (recovery) MP application. Both I-E flow rate and pressure were increased from resting significantly in all frequencies MP, but they were not different among the 3 frequency ranges. The E flow rate was increased to 0.41 - 0.44, 0.49 - 0.52 and 0.41 - 0.49 L/s (min-max) during MP application at low, medium, and high frequency compared to resting (0.31 - 0.36 L/s), respectively. The E pressure was increased to 0.40 - 0.41, 0.44 - 0.47 and 0.39 - 0.47 cmH2O (min-max) during MP application at low, medium, and high frequency compared to resting (0.20 - 0.22 cm H2O), respectively. However, the increment of the 3 frequency ranges did not affect the cardiovascular functions except respiratory rate, which was increased only 2 breaths/min from resting. In conclusion, airflow and pressure were slightly increased during MP but did not affect cardiopulmonary functions in healthy subjects. Further study in patients is needed. HIGHLIGHTS Manual chest wall percussion is a secretion clearance technique which commonly used. Whether manual chest wall percussion frequency is capable of increasing expiratory flow rate by the same amount. The percussion force might be the most prominent factor affecting the expiratory flow rate. The frequency of chest wall percussion does not affect cardiovascular response. Medium and high frequencies cause a minor rise in the respiratory rate but have no impact on minute ventilation.