Ventilation Mode Improves Lung Mechanics in Emergency Surgery

Pressure control-volume guarantee (PCV-VG) ventilation improved intraoperative respiratory mechanics but did not significantly reduce postoperative pulmonary complications (PPCs) compared with conventional volume control ventilation (VCV) in patients undergoing emergency abdominal surgery, according to a randomized controlled trial.

Patients undergoing emergency laparotomy are at high risk of developing postoperative pulmonary complications, which are associated with prolonged hospital stays, increased healthcare costs, and higher mortality. Optimising intraoperative ventilation has become an important strategy for reducing lung injury during surgery. PCV-VG combines the pressure-limiting benefits of pressure-controlled ventilation with the delivery of a guaranteed tidal volume, potentially improving lung protection while maintaining adequate ventilation.

Trial Compared Two Ventilation Strategies

Researchers conducted a single-centre randomized controlled trial involving 106 adults undergoing emergency laparotomy expected to last more than two hours under general anaesthesia.

Participants were randomly assigned to receive either PCV-VG or conventional volume control ventilation throughout surgery. The primary outcome was the development of postoperative pulmonary complications within seven days, assessed using the Melbourne Group Score version 2 (MGS-2).

Secondary outcomes included respiratory mechanics during surgery, lung aeration assessed by ultrasound, oxygenation, hospital length of stay, oxygen-free days, and mortality.

Better Respiratory Mechanics During Surgery

One hour after surgery began, patients receiving PCV-VG demonstrated significantly improved respiratory mechanics compared with those receiving conventional ventilation.

Respiratory system compliance was higher, while both driving pressure and mechanical power—two measures associated with ventilator-induced lung injury—were lower in the PCV-VG group.

These findings suggest the ventilation mode may reduce mechanical stress on the lungs during surgery by delivering tidal volumes more efficiently while limiting airway pressures.

However, oxygenation and lung aeration scores were similar between the two groups.

Clinical Outcomes Were Comparable

Despite the physiological improvements observed during surgery, the primary clinical outcome did not differ significantly between groups.

Median postoperative pulmonary complication scores were comparable, and statistical analysis found no significant reduction in overall PPC rates with PCV-VG.

Using the Melbourne Group Score definition, postoperative pulmonary complications occurred in 3.8% of patients receiving PCV-VG compared with 17% of those receiving volume control ventilation. Although this numerical difference favoured PCV-VG, the study was not powered to determine whether this reflected a true clinical benefit.

Other patient-centred outcomes, including oxygen-free days, hospital length of stay, and mortality, were also similar between groups.

Larger Studies Needed

The authors conclude that PCV-VG offers measurable physiological advantages during emergency laparotomy by improving respiratory system mechanics and reducing driving pressure and mechanical power.

However, these improvements did not translate into a statistically significant reduction in postoperative pulmonary complications in this study. The researchers note that the relatively small sample size may have limited their ability to detect differences in clinical outcomes.

They suggest that larger multicentre trials are now needed to determine whether the intraoperative benefits of PCV-VG ultimately improve postoperative recovery and reduce pulmonary complications in higher-risk surgical populations.

Reference

Jassal N et al. Volume Control Ventilation versus Pressure Control- Volume Guarantee Ventilation in Emergency Surgery: A Randomized Controlled Trial. Surgery. 2026; 10.1016/j.surg.2026.110438.