# Comparison Between Synchronized Intermittent Mandatory Ventilation (SIMV) and Adaptive Support Ventilation (ASV) on Patient Outcomes in Critically Ill Patients: A Systematic Review and Meta-Analysis

## TL;DR

This study compares two ventilation modes, ASV and SIMV, and finds that ASV reduces mechanical ventilation duration and peak airway pressure in critically ill patients.

## Contribution

A systematic review and meta-analysis comparing ASV and SIMV in critically ill patients, focusing on clinical and physiological outcomes.

## Key findings

- ASV significantly reduced mechanical ventilation duration and ventilator days compared to SIMV.
- ASV was associated with lower peak airway pressure than SIMV.
- No significant differences were found in ICU length of stay or most physiological parameters.

## Abstract

In critically ill patients, the choice of mechanical ventilation modes can have a significant impact on patient outcomes. The comparative efficacy of adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation (SIMV) remains debated in the literature. Therefore, this systematic review and meta-analysis aimed to investigate the impact of ASV compared to SIMV in critically ill patients. For this systematic review and meta-analysis, a thorough search was undertaken in PubMed, Web of Science, and Scopus. Primary outcomes included length of mechanical ventilation, ventilator days, and intensive care unit (ICU) length of stay (LOS), whereas secondary outcomes focused on physiological parameters (e.g., P-peak, hemodynamics, gas exchange). A total of 11 studies involving 627 patients were included. The results showed that ASV significantly reduced the length of mechanical ventilation (mean difference (MD): -0.80 days; 95% CI: -1.11 to -0.50; p<0.00001) and ventilator days (MD: -1.42 days; 95% CI: -1.83 to -1.01; p<0.00001) compared to SIMV. However, no differences were observed in ICU LOS (p=0.25), heart rate (p=0.17), minute volume (p=0.72), mean arterial pressure (p=0.26), PCO2 (p=0.97), PO2 (p=0.22), and respiratory rate (p=0.55). P-peak, however, was significantly higher in SIMV compared to ASV (MD: -2.16; 95% CI: -3.07 to -1.25; p<0.00001). The findings of the systematic review showed that ASV was associated with a shorter duration of mechanical ventilation and lower peak airway pressures than SIMV, which suggests its advantage in facilitating weaning and lung-protective ventilation. ASV may be preferable in ICU settings where reducing ventilation duration is critical. The findings of the present systematic review were limited by high heterogeneity and study quality variations. Therefore, further research is required to validate other non-significant outcomes.