Evaluation of user behaviour with an Oscillating Positive Expiratory Pressure (OPEP) device in paediatric cystic fibrosis patients.

Abstract

Background: OPEP devices are indicated to remove excess secretions and reduce gas trapping in patients with hypersecretory pulmonary diseases e.g. Cystic Fibrosis (CF), bronchiectasis, chronic bronchitis. OPEP works by actively exhaling to functional residual capacity via a fixed resistor, to generate mean pressures of 10-20 cmH2O at a flow rate of 10-20 L/min, with an Inspiration: Expiration (I:E) ratio of 1:3 or 1:4. The current study sought to evaluate user behaviour during OPEP therapy in paediatric CF patients. Methods: 21 paediatric patients were recruited at the CF unit in University Hospital Limerick, Ireland. Each subject used an OPEP device twice daily and received standardised training and instructions from the same specialist physiotherapist. Use behaviour was evaluated using a flow and pressure sensor placed in-line between the subject’s mouth and OPEP device. Each subject was asked to perform ten expirations as per their normal routine. Each expiration was recorded separately for analysis. Results: None of the subjects achieved the specified therapeutic ranges during expiration (Figure 1). Mean pressure = 16.19 cmH2O [SD=6.78], with a mean flow = 31.28 L/min [SD=8.85]. Mean Expiration length = 2.53s [SD=1.36], with mean I:E ratio = 1:1.24 [range: 1:0.36 – 1:2.42]. Interpretation: Despite standardised instruction and good adherence to twice daily OPEP therapy, subjects demonstrated poor technique and large variance during use. Multiple cofounding factors may contribute to this phenomenon.