Hemodynamic Effects of Volume-Controlled Ventilation Versus Pressure-Controlled Ventilation in Head Trauma Patients

Abstract

Background. Controlled ventilation for head trauma patients should reduce hypoxemia, hypercapnia and prevent secondary brain injury. However, changes in cardiac output and arterial blood pressure are the common consequences of mechanical ventilation. This study was designed to compare pressure- versus volume-controlled ventilation modes in severe head trauma patients to identify the mode with least hemodynamic compromise and best oxygenation profile. Methods. This prospective crossover study was carried out on 15 severe head trauma patients admitted to surgical ICU for mechanical ventilation and critical care. All patients were initially ventilated with volume-controlled ventilation for 12 hours then the mode of ventilation was changed to pressure-controlled ventilation for the next 12 hours. Arterial and pulmonary artery catheters were inserted for continuous monitoring of arterial blood pressure, cardiac output, pulmonary artery pressure, pulmonary wedge pressure, pulmonary vascular resistance, and systemic vascular resistance every 4 hours from the start of each ventilation mode. Lung mechanics and arterial blood gases were simultaneously recorded during the times of hemodynamic monitoring. Results. Cardiac output did not show significant changes between the 2 ventilation modes and mean group differences at 4, 8, and 12 hours were −0.2, −0.2, −0.1 L/min (95% confidence interval = −1.04 to 0.64, −0.92 to 0.52, and −0.68 to 0.48 L/min), respectively. Additionally, the other hemodynamic variables were comparable at all levels of study analysis. Volume-controlled ventilation was associated with significant higher peak air way pressure in comparison with pressure-controlled ventilation after 4, 8, and 12 hours. The oxygenation values and other lung mechanics were not significantly change between the 2 ventilation modes. Conclusion. Both volume-controlled and pressure-controlled ventilations have comparable hemodynamic and oxygenation profiles in severe head trauma patients for short-term ventilation.