Preventing ventilation induced lung injury depends on giving the right number ...( ice into three experimental groups. All...)

• HV (high volume) received one deep inflation each breath

• LV (low volume) received two deep inflations each hour

• LVDI (low volume deep inflation) received two deep inflations each minute

In addition, there were two control groups -- a surgical sham, which received no ventilation, and a group that received deep inflation every breath and no PEEP.

The study found that:

• The lungs of the mice given two big breaths every minute (LVDI) remained more open and functioned better than the LV and HV.

• The lungs of the mice that received only two deep breaths per hour (LV) became stiff and portions of the lungs collapsed. However, lung function returned briefly to normal when the mice received their infrequent deep inflations. This suggests that the lungs self-repair after the deep inflation, at least over the course of the first two hours.

• The lungs of the mice that received deep inflation every breath (HV) suffered overdistention injury to their lungs. This group was akin to a high tidal volume group, once again demonstrating that low tidal volume is safer.

• The control group that received high tidal volume but no PEEP showed the highest evidence of injury, even higher than the high tidal volume group. This indicates that PEEP helps reduce the negative effects of frequent deep inflation.

"We demonstrated it's possible to give deep breaths too frequently and too seldom," Bates explained. The middle ground -- two deep inflations per minute -- provides the most benefit to the mice we studied without injuring the lungs, he said.

"We conclude that frequent deep inflation can safely
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Contact: Christine Guilfoy
cguilfoy@the-aps.org
301-634-7253
American Physiological Society
25-Jul-2006