Comparison of Effects of Manual and Mechanical Airway Clearance Techniques on Intracranial Pressure in Patients With Severe Traumatic Brain Injury on a Ventilator: Randomized, Crossover Trial

Abstract

Background Physical therapist intervention can play a significant role in the prevention of mechanical and infectious complications in patients with traumatic brain injury (TBI) who are mechanically ventilated. Objective The objective of this study was to observe and compare the effects of manual and mechanical airway clearance techniques on intracranial pressure (ICP) and hemodynamics in patients with severe TBI. Design The design was a prospective, randomized, crossover trial. Setting The setting was a neurointensive care unit at a level 1 trauma center. Patients Forty-six adult patients aged 18 to 75 years, of either sex, with severe TBI, receiving mechanical ventilatory support with continuous ICP monitoring, and undergoing regular airway clearance techniques participated in this study. Intervention Two techniques were performed by a single trained physical therapist. Treatment A was a manual chest percussion technique and treatment B used a mechanical chest wall vibrator. Each treatment was applied for 10 minutes alternately, separated by an interval of 4 hours. Measurements ICP was measured from the start of intervention to 10 minutes postintervention. Secondary measurements included cerebral perfusion pressure, heart rate, mean arterial pressure (each from the start of the intervention until 10 minutes postintervention at 1-minute intervals), and arterial blood gas parameters (from just before the start of the intervention and 10 minutes postintervention). Results The increases in mean (95% CI) intracranial pressure of 2.4 (1.4-3.4) and 1.0 (0.2-1.8) mmHg, during and after the intervention with treatment A, respectively, were statistically significantly higher than for treatment B, irrespective of sequence. In contrast, a mean heart rate rise of 6.4 (3.3-9.5) beats/min and mean arterial pressure rise of 5.3 (2.0-8.6) mmHg were significantly higher only during the intervention phase of treatment A compared with treatment B. Peak mean values of ICP, heart rate, and arterial pressure were also significantly higher during treatment A. However, mean values of cerebral perfusion pressure or its degree of change were statistically comparable in both treatment groups. Limitations Patients with high baseline ICP values (>20 mmHg) were excluded, and, because of the crossover design, the effect of individual technique on final (long-term) neurological or respiratory outcomes could not be studied. Conclusion Manual chest percussion technique in patients with severe TBI was associated with statistically significant transient increases in ICP and hemodynamics, compared with the mechanical method. However, such transient increases in ICP by either technique were not clinically relevant in patients with moderate-to-severe TBI without intracranial hypertension on a mechanical ventilator.