Relation between ventilatory pressures and intra-abdominal pressure

Introduction

The intra-abdominal pressure (IAP) may increase in critically ill ventilated patients inducing abdominal compartment syndrome with irreversible intra-abdominal organ ischemia. Increases in positive end-expiratory pressure (PEEP) induce an increase in plateau pressure (Pplat) and in intrathoracic pressure, which lead to hemodynamic changes and may also increase IAP by pressure transmission through the diaphragm. The aim of this study was to evaluate the relation between Pplat changes induced by PEEP and IAP.

Methods

During a 6-month period, 278 measurements were prospectively performed in 27 ICU patients. Pplat and IAP were measured 20 minutes after changes in the PEEP level. IAP measurement was performed using an intravesical pressure monitoring method by clamping the Foley urinary tube after injection of 30 ml normal saline, under sterile conditions. Statistical analysis was performed using parametric and nonparametric tests, as appropriate, and correlation tests. See Figure 1.

Figure 1

Results

Twenty-seven patients (22 males, five females) were included with a mean age of 58.2 years. The overall relation between Pplat and IAP was significant (r² = 0.143, P < 0.001).

Conclusion

Our study shows that ventilatory pressure is a factor of the increase in IAP. In patients with high risk of intra-abdominal hypertension, therefore, IAP monitoring using a vesical pressure method may be useful before and after each PEEP adjustment.