New RCT on intraoperative ventilation strategies is out: PROVHILO. Low tidal volume ventilation (LTVV) has been settled as the way to go, but what about PEEP and recruitment maneuvers? Wouldn’t high PEEP and regular lung recruitment make sense in patients at risk for post-OP lung complications? Apparently not. This rather big multi-centre trial showed no difference in lung complications between the groups. But a higher incidence of intraoperative hypotension in the high PEEP group. But is that the whole story?
900 patients scheduled for open abdominal surgery across 30 centres in Europe and America. All receiving LTVV. Randomised to a rather high PEEP of 12 and regular recruitment maneuvers, or to low PEEP 0-2. The result was no difference in post-OP lung complications. But a higher incidence of hypotension, use of vasopressor and giving the patient more fluid during surgery. So, no difference in main outcome, but a lot of bad side effects. How could this be?
The patients for the PROVHILO trial were chosen based on ARISCAT criteria. They include age, pre-OP sat% and type of surgery. But not patient weight. BMI >40 was even excluded from the study. In my world, the big guys, with a lot of weight pushing on the their lungs are excellent candidates for higher PEEP.
What happened in this study, was applying slightly extreme settings to a large, random group. It would have been surprising if they found a positive difference. The whole point of a good ventilator strategy – or any medical treatment – is to have some guidelines, often set by big trials, and then individualise as you apply your clinical knowledge to each patient. Keeping a PEEP of 12 with circulatory effects in an otherwise healthy patient doesn’t make sense. Applying PEEP of 12 and recruitment maneuvers on indication in selected patients might well be a good strategy, even if applying these settings categorically to large, random groups of patients is a bad idea.