effects of different levels of auto-PEEP on hemodynamics in mechanically ventilated patients, correlation with lung mechanics and gas exchange in different ventilator settings

ABSTRACT

The goal of this study was to detect auto-PEEP in mechanically ventilated patients and monitor how its different levels may affect the patients hemodynamics, lung mechanics and gas exchange and trial of estimating an optimal PEEP level. Another goal was to monitor how the addition of external PEEP may affect the patient hemodynamics, lung mechanics and gas exchange and trial of estimating an optimal PEEP level. This study included 18 mechanically ventilated patients who were classified into three groups COPD group [10 patients], restrictive group [4 patients] and normal group [4 patients]. Besides the routine clinical examination, ECG, chest X-ray, laboratory investigation and ABG, each individual patient was subjected to serial monitoring of hemodynamic parameters [SV, PCWP, LVSW, RVSW, PVR], lung mechanics parameters [auto-PEEP, external PEEP, total PEEP, P pressure, P mean, P total, Raw, C stat]. This is done for base line readings and after every change in ventilatory settings according to the study on different levels of auto-PEEP and on different levels of external PEEP. The results showed that auto-PEEP was detected in 13 out of 18 patients included in the study [72%] with mean of 6.8 cm H2O SD 5. On application of external PEEP, auto-PEEP had a significantly negative correlation with external PEEP in all groups