Comparison of Volume Support, Volume-Assured Pressure Support, and Spontaneous Modes in Postoperative Early Extubated Patients

Abstract

Background: This study aimed to compare respiratorily, arterial blood gas (ABG), and hemodynamics parameters among patients undergoing surgery who were admitted to intensive care unit (ICU), using three ventilation modes, including volume-assured pressure support (VAPS), volume support (VS), and spontaneous modes. Materials and Methods: One hundred and thirty-two patients were randomly assigned into three groups of VAPS, VS, and spontaneous modes utilizing randomized block procedure. Patients were followed between 12 and 30 h until extubation. Respiratory parameters including; peak inspiratory pressure (PIP), static compliance, resistance, rapid shallow breathing index (RSBI), and P 0.1(P0.1 correlates with respiratory drive and is defined as the negative pressure measured at the airway opening 100 ms after the initiation of an inspiratory effort), along with ABG parameters including; pH level, PaCO2,HCO3,PaO2/FiO2 ratio, extra hydrogen ion, and hemodynamics parameters including; mean arterial blood pressure and heart rate were measured every 3 h and compared among groups. Results: All studied parameters in three groups improved during the study. PIP, Resistance, PH, HCO3, extra hydrogen ion, PCo2, PaO2/FiO2 ratio, mean arterial blood pressure were similar among the three groups in most of the time points (P > 0.05). In most of the time points, RSBI (from 92.7 to 55.4), P 0.1 (from 6.8 to 1.7) in the VAPS group, static compliance (from 55.3 to 55.7) in the VS group, and heart rate (from 108.5 to 90.1) in spontaneous groups were significantly better than other modes (P < 0.05). Changes in RSBI, P 0.1, PCo2, HCO3, and heart rate during the study were significantly different among studied groups (P < 0.05). The length of stay in the ICU in patients who underwent VAPS was significantly shorter than the other modes. Conclusions: VAPS mode with better effects or at least as effective as VS and spontaneous modes could be select as the best mode of ventilation in postoperative early extubated patients admitted to ICU.