The Nippy Clearway is a new mechanical insufflation-exsufflation device used to assist cough.
We compared the peak expiratory flow (PEF) with the Nippy Clearway versus the CoughAssist in a bench experiment. The relationship between PEF and pressure at the airway opening during exsufflation (minimum expiratory PAO) was investigated under 6 combinations of compliance (30 or 60 mL/cm H2O) (C30 and C60) and resistance (0, 5, or 20 cm H2O/L/s) (R0, R5, and R20) over a 25-50 cm H2O range of set P(AO). The intercepts and slopes of the linear regression performed over PEF and P(AO) relationships were compared for both devices.
For the C30R0, C30R5, and C60R5 conditions, the change in both the intercepts and slopes was significant with the Nippy Clearway, compared to the CoughAssist, averaging -2.96 L/s and -0.03 L/s/cm H2O, -1.46 L/s and 0.02 L/s/cm H2O, and -1.02 L/s and -0.04 L/s/cm H2O, respectively. As a result, at any minimum expiratory P(AO), PEF was significantly greater with the Nippy Clearway. For C30R20 and C60R20, the regression lines were similar for the Nippy Clearway and CoughAssist.
In this bench study, PEF with the Nippy Clearway was greater than with the CoughAssist at low respiratory-system compliance.