[Intraabdominal and thoracic pressure in critically ill patients with suspected intraabdominal hypertension].

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.