Effects of positive end expiratory pressure (PEEP) in right ventricular function

Introduction

The addition of high levels of PEEP in patients under mechanical ventilation can be part of recruitment maneuvers and alveolar protection. However, it can also cause deleterious effects in the right ventricular function.

Methods

We studied 16 patients admitted in a trauma ICU during the period January–August 2003. All patients were under mechanical ventilation and without significant pulmonary disease. They were submitted to the systematic increase of PEEP from ZEEP to 5, 10, 15, 20 and 25 cmH₂O every 10 min. At the same time, we measured the haemodynamic effects and alterations in the oxygen transportation.

Results

All were traumatic patients, without significant pulmonary disease. The mean age was 34.3 ± 11.9 years, 87.5% were male, the mean APACHE II score was 26.4 ± 4.5, the mean SAPS II score was 44.9 ± 11.9 and the initial mean SOFA score was 5.8 ± 1.4. The addition of PEEP caused progressive increase of the pulmonary artery pressure, of the central venous pressure (CVP) and of the oxygen extraction rate. At the same time, it caused progressive decrease of the cardiac index (CI) and the right ventricular systolic work index (RVSWI). The CVP increased from 13.3 ± 5.5 to 21.8 ± 4.4, the CI decreased from 5.0 ± 1.6 to 4.1 ± 2.1 and the RVSWI decreased from 10.6 ± 6.2 to 7.0 ± 5.9. All these alterations were statistically significant (P < 0.05).

Conclusions

The addition of PEEP in patients under mechanical ventilation and without significant pulmonary disease can cause progressive right ventricular dysfunction. Haemodynamic care and support should be taken during PEEP increases for recruitment maneuvers and alveolar protection, even if this is done for short periods of time.