New Study Examines Ventilator Treatment Strategies for Patients With Severe Respiratory Disorders

A comparison of two treatment methods for critically ill patients with severe, rapid-onset lung disorders treated with mechanical ventilators found no significant difference in the risk of death, but did find that the newer method reduced the rates of severe persistent low oxygen levels and reduced the need for additional “rescue” therapies, according to a study in the February 13 issue of JAMA.

Acute lung injury (such as from severe pneumonia or trauma) and acute respiratory distress syndrome (ARDS; the most serious form of acute lung injury), can be devastating complications of critical illness. Although mechanical ventilation provides essential life support, it can worsen lung injury. Low tidal volume (volume of air that is drawn with each breath) ventilation reduces the risk of death in critically ill patients with acute lung injury and ARDS. Adding therapies to effectively splint open collapsed lung segments may further reduce the risk of death, the authors write.

Maureen O. Meade, M.D., M.Sc., of Hamilton Health Sciences and McMaster University, Hamilton, Ontario, Canada, and colleagues examined the effect on death of an experimental “lung open ventilation” (LOV) strategy combining low tidal volumes, recruitment maneuvers (periodic sighs on the ventilator to open the lung) and high levels of positive end-expiratory pressure (PEEP; to keep the lung open) compared with an established low-tidal-volume strategy (control group) in 983 patients with moderate and severe lung injury. The randomized trial (the LOV study) was conducted between August 2000 and March 2006 in 30 intensive care units in Canada, Australia and Saudi Arabia.

All-cause hospital death rates were 36.4 percent in the experimental group and 40.4 percent in the control group. Barotrauma rates (injury to the lung caused by the pressure of the ventilator) were 11.2 percent and 9.1 percent, respectively.

“… for patients with acute lung injury and ARDS, we found similar mortality in patients with a multi-faceted protocolized lung-protective ventilation strategy designed to open the lung compared with an established low-tidal-volume protocolized ventilation strategy. We found no evidence of significant harm or increased risk of barotrauma despite the use of higher PEEP. In addition, the ‘open-lung’ strategy appeared to improve oxygenation, with fewer hypoxemia-related deaths and a lower use of rescue therapies by the treating clinicians. Our results, in combination with the two other major trials, justify use of higher PEEP levels as an alternative to the established low-PEEP, low-tidal-volume strategy,” the authors write.

JAMA. 2008; 299[6]:637-645.