RESUMO
OBJECTIVE: To study the correlation between intraabdominal and intrathoracic pressure in patients with suspected intraabdominal hypertension. DESIGN: A prospective, observational cohort study. SETTING: Polyvalent intensive care unit of a University hospital. PATIENTS: Twenty-seven medical-surgical patient dependent upon controlled mechanical ventilation due to acute respiratory failure and with several risk factors for intraabdominal hypertension (IAH). MAIN VARIABLES: Intraabdominal (IAP), esophageal (Peso) and airways pressure were measured under static (st) and dynamic (dyn) conditions. Respiratory system (Crs), lung (Cl) and chest wall compliance (Ccw)were calculated. RESULTS: In 10 patients IAP > 12 mmHg (IAH, IAPst, 14 ± 2 [12-21] mmHg), while in the rest the pressure proved normal (n = 17; IAPst, 8 ± 2 [3-11] mmHg). Peso st was 11 ± 5 (2-27) and Peso dyn 7 ± 4 (2-24) cmH2O. Depending on the presence or absence of IAH, Peso st was 9 ± 4 vs 7 ± 3 cmH2O (p = 0.2) and Peso dyn 6 ± 2 vs 4 ± 3 cmH2O (p = 0.3), respectively. The correlation between Peso st and dyn with IAPst was 0.5 (p= 0.003) and 0.4 (p = 0.03), respectively. The compliance components were decreased (Crs, 31 ± 8; Cl, 52 ± 22 and Ccw, 105 ± 50 ml/cmH2O); Ccw was significantly lower in patients with IAH (81 ± 31 vs 118 ± 55 ml/cmH2O; p = 0.02). The correlation coefficient between IAPst and Ccw was -0.7 (p < 0.001), and -0.5 (p = 0.002) with respect to Crs. CONCLUSIONS: A stiffer chest wall was observed in patients with IAH. In patients with risk factors for IAH, pressures in these compartments were highly variable.
