Tubing internal diameter affects the pressures and oscillation frequencies generated by the therapist-made bubble-positive expiratory pressure device.

Objectives: To determine the positive expiratory pressures (PEP) and oscillation frequencies generated in the therapist-made-bubble-PEP device using tubing with different internal diameters (IDs). Design: Bench-top experimental study. Therapist-made-bubble-PEP device with a 10 cm column height of water, tubing length of 30 cm with distal end of the tubing resting 3 cm from base of container. Tubing with 2, 4, 5, 7, 8, and 10 mm IDs were tested with flows of 5, 10, 15, 20, and 25 L/min. A pressure transducer measured the pressures and oscillation frequencies. Data were captured with PhysioDAQxs© software and analyzed with Breathalyser© software. Results: Therapist-made-bubble-PEP device with: (1) 2 mm ID tubing with 5 and 10 L/min flows produced mean(SD) PEP of 20.1(0.2) and 41.8(0.5)cmH2O, respectively, oscillation frequencies of 15-19 Hz; (2) 4 mm ID tubing with 5 and 25 L/min flows produced PEP of 12.5(0.2) and 41.5(0.3)cmH2O, oscillations of 14-18 Hz; (3) 5 mm ID tubing with 5 and 25 L/min flows produced PEP of 10.9(0.1) and 15.8(0.1)cmH2O, oscillations of 17-18 Hz; (4) 7 mm ID tubing with 5 and 25 L/min flows produced PEP of 10.7(0.0) and 12.7(0.2)cmH2O, oscillations of 14-17 Hz; (5) 8 mm ID tubing with 5 and 25 L/min flows produced PEP of 10.5(0.0) and 11.4(0.0)cmH2O, oscillations of 14-18 Hz; and (6) 10 mm ID tubing with 5 and 25 L/min flows produced PEP of 10.4(0.1) and 10.8(0.2)cmH2O, oscillations of 13-17 Hz. Conclusions: Therapist-made-bubble-PEP device with tubing of 10 mm ID generated the most stable PEP in relation to water height (10 cm) irrespective of flow compared to tubing with ID of 2, 4, 5, 7, and 8 mm. The oscillation frequencies generated at all flows and tubing IDs were between 13 and 19 Hz.

Pressures and Oscillation Frequencies Generated by Bubble-Positive Expiratory Pressure Devices.

BACKGROUND: Positive expiratory pressure (PEP) devices are used to assist with airway clearance. Little is known about the therapist-made or commercially available bubble-PEP devices. The aim of this study was to determine the end-expiratory pressures (cm H2O) and oscillation frequencies (Hz) generated when a range of flows were applied to the therapist-made bubble-PEP devices (Bubble-PEP-3cm and Bubble-PEP-0cm) and commercial bubble-PEP devices (AguaPEP, Hydrapep, and Therabubble). METHODS: This was a bench-top experimental study using a compressed air source, flow rotameter (flows of 5, 10, 15, 20, and 25 L/min), and pressure transducer. Data were collected using a data acquisition device with PhysioDAQxs software and analyzed with Breathalyser software to determine the pressures and oscillation frequencies generated by 5 bubble-PEP devices. Each flow was constant for a 30-s measurement period, and measurements were repeated in triplicate. The 5 devices were: a therapist-made Bubble-PEP-3cm device (filled with 13 cm of water, tubing resting 3 cm from the base of the container); the therapist-made Bubble-PEP-0cm (filled with 10 cm of water, tubing resting at the base of the container); and the AguaPEP, Hydrapep, and Therabubble devices with water to the 10 cm mark on the containers. RESULTS: Flows of 5-25 L/min produced the following mean ± SD PEP and oscillation frequencies (Hz): the Bubble-PEP-3cm produced PEP of 10.4 ± 0.14 to 10.8 ± 0.24 cm H2O, oscillations between 13 and 17 Hz; the Bubble-PEP-0cm produced PEP of 10.9 ± 0.01 to 12.9 ± 0.08 cm H2O, oscillations between 12 and 14 Hz; the AguaPEP produced PEP from 9.7 ± 0.02 to 11.5 ± 0.02 cm H2O, oscillations between 11 and 17 Hz; the Hydrapep produced PEP of 9.6 ± 0.35 to 10.7 ± 0.39 cm H2O, oscillations between 14 and 17 Hz; and the Therabubble produced PEP from 8.6 ± 0.01 to 12.8 ± 0.03 cm H2O, oscillations between 14 and 17 Hz. CONCLUSIONS: Bubble-PEP-3cm maintained the most stable pressure throughout the range of flows tested. All devices investigated produced similar oscillation frequencies.

Development of a method for measuring femoral torsion using real-time ultrasound.

Excessive femoral torsion has been associated with various musculoskeletal and neurological problems. To explore this relationship, it is essential to be able to measure femoral torsion in the clinic accurately. Computerized tomography (CT) and magnetic resonance imaging (MRI) are thought to provide the most accurate measurements but CT involves significant radiation exposure and MRI is expensive. The aim of this study was to design a method for measuring femoral torsion in the clinic, and to determine the reliability of this method. Details of design process, including construction of a jig, the protocol developed and the reliability of the method are presented. The protocol developed used ultrasound to image a ridge on the greater trochanter, and a customized jig placed on the femoral condyles as reference points. An inclinometer attached to the customized jig allowed quantification of the degree of femoral torsion. Measurements taken with this protocol had excellent intra- and inter-rater reliability (ICC2,1 = 0.98 and 0.97, respectively). This method of measuring femoral torsion also permitted measurement of femoral torsion with a high degree of accuracy. This method is applicable to the research setting and, with minor adjustments, will be applicable to the clinical setting.