Hemodynamic and Ventilatory Responses to Head-down Postural Drainage Position

The purpose of this study is to explore acute hemodynamic and ventilatory responses to head-down 30 degree postural drainage position in patients with blunt chest and/or abdominal injury in the traumatic intensive care unit.

Study Protocol The study protocol consisted of 2 conditions: treatment condition (A) and sham condition (B). The order of the conditions was randomly assigned to either the treatment or sham for the first round and vise versa in the second round in a balanced cross-over design (A-B-B-A) so there were four sets of measurements per patient. For the treatment condition (A), the study consists of three consecutive periods 1) baseline period: 10 minutes rest in horizontal supine lying 2) intervention period: 10 minutes rest in head-down 30 degree supine lying 3) recovery period: return to horizontal supine lying and rest for 10 minutes . For the Sham condition (B), the study was performed with a similar procedure except the intervention period consisted of horizontal supine lying. Hemodynamic and ventilatory parameter were recorded at the start of each period (0 min) and every 2 minute until end of each period for both conditions. Hemodynamic and ventilatory dependent variables were heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), electrocardiography (ECG), central venous pressure (CVP), respiratory rate (RR), oxygen saturation (SpO2), tidal volume (VT), minute ventilation (VE), dynamic lung compliance (Cdyn) and end-tidal expiratory pressure of CO2 (PETCO2). Subjects were rested between each condition. Subjects were suctioned via endotracheal tube to clear airway at 10 minutes before study commencement of either A-B or B-A.