The effects of various peep levels on intraabdominal pressure and hemodynamics in critically ill patients

Introduction: In this study, it was aimed to compare the effects of three different PEEP levels (0-4, 5-8, 9-12 cmH2O) on intraabdominal pressure and hemodynamic parameters of patients in intensive care unit. Method: Patients between 18-80 years old whom were mechanically ventilated without any spontaneous respiratory efforts on supine position were included into the study. Bladder pressure measurement as a practical and frequently preferred method was used in order to measure intra-abdominal pressure. 100 ml isotonic fluid was given during the measurement. Level of symphysis pubis was chosen for zeroing the pressure transducer to measure the intra-abdominal pressure. Three patient groups, each containing 22 cases, totally 66 patients were planned in this study. All patients were mechanically ventilated with various PEEP levels. The patients with 0-4 cmH2O PEEP levels were named Group 4; the patients with 5-8 cmH2O PEEP levels were named Group 8; the patients with 9-12 cmH2O PEEP levels were named Group 12. The levels of patients' PEEP levels were arranged by the responsible intensive care physician regarding to the patients' clinic. Intraabdominal, central venous, arterial blood pressures, pulse rates, peripheric oxygen saturation, body temperature, instant fluid balances and amounts of urine (in ml/kg/hour unit) of the patients were measured on the 0. 6. 12. 18. and 24. hours and recorded. Results: If we look at the gender distributions of the groups: 56 males and 8 females were studied. There were no statistical differences between three groups in terms of the demographic characteristics such as age, BMI, body weight of 64 patients (p>0,05). The lowest IAP levels were recorded in Group 4; the highest levels were recorded in Group 12. IAP levels were significantly higher in the hours of 0, 6, 12, 18, and 24 in Group 12 than the other groups (p<0,05). Pulse rates were higher in Group 4 than Group 12 in the first 12 hours. Systolic blood pressures, diastolic blood pressures, mean blood pressures and average body temperatures of the groups were statistically similar (p>0,05). There were no significant differences found in terms of Central Venous Pressure (CVP) measures (p>0,05). When the groups were analysed in terms of urine output, there were no significant differences found between the groups (p>0,05). There were no significant differences found between the groups in terms of instant fluid balance (p>0,05). Conclusion: IAP was found lower in patients with lower PEEP levels vice versa higher IAP was found in patients with higher PEEP levels applied via the same mechanical ventilation mode. These increases in IAP in accordance with the increased PEEP levels were thought to induce minimal intra-abdominal hipertension (IAH), still not to affect the hemodynamics. Furthermore it is thought that more studies are needed research the effects of higher PEEP levels on IAP.