Effect of decompressive laparotomy on organ function in patients with abdominal compartment syndrome: a systematic review and meta-analysis.

BACKGROUND: Decompressive laparotomy has been advised as potential treatment for abdominal compartment syndrome (ACS) when medical management fails; yet, the effect on parameters of organ function differs markedly in the published literature. In this study, we sought to investigate the effect of decompressive laparotomy on intra-abdominal pressure and organ function in critically ill adult and pediatric patients with ACS, specifically focusing on hemodynamic, respiratory, and kidney function and outcome. METHODS: A systematic review and meta-analysis of the literature was performed. Articles reporting data on intra-abdominal pressure (IAP), hemodynamic (mean arterial pressures [MAP], central venous pressure [CVP], cardiac index [CI], heart rate [HR], systemic vascular resistance index [SVRI] and/or pulmonary capillary wedge pressure [PCWP]), respiratory (positive end-expiratory pressure [PEEP], peak inspiratory pressure [PIP] and/or ratio of partial pressure arterial oxygen and fraction of inspired oxygen [P/F ratio]), and/or urinary output (UO) following decompressive laparotomy were analyzed. RESULTS: A total of 15 articles were included; 3 included children only (aged 18 years or younger). Of the 286 patients who were included, 49.7% had primary ACS. The baseline mean IAP in adults decreased with an average of 18.2 ± 6.5 mmHg following decompression, from 31.7 ± 6.4 mmHg to 13.5 ± 3.0 mmHg. There was a decrease in HR (12.2 ± 9.5 beats/min; p = 0.04), CVP (4.6 ± 2.3 mmHg; p = 0.022), PCWP (5.8 ± 2.3 mmHg; p = 0.029), and PIP (10.1 ± 3.9 cmH2O; p < 0.001) and a mean increase in P/F ratio (70.4 ± 49.4; p < 0.001) and UO (95.3 ± 105.3 ml/h; p < 0.001). In children, there was a significant increase in MAP (20.0 ± 2.3 mmHg; p = 0.006), P/F ratio (238.2; p < 0.001), and UO (2.88 ± 0.64 ml/kg/h; p < 0.001) and a decrease in CVP (7 mmHg; p = 0.016) and PIP (9.9 cmH2O; p = 0.002). The overall mortality rate was 49.7% in adults and 60.8% in children following decompressive laparotomy. CONCLUSIONS: Decompressive laparotomy resulted in a significantly lower IAP and had beneficial effects on hemodynamic, respiratory, and renal parameters. Mortality after decompressive laparotomy remains high in both adults and children.

Effect of intra-abdominal pressure on abdominal wall blood flow.

Adverse effects of increased intra-abdominal pressure (IAP) on cardiac, pulmonary, and renal function have been well described. Abdominal wound healing complications seen in the massively injured patient may also be associated with IAP. The effects of IAP on abdominal wall blood flow, however, have not been documented. This study examines rectus sheath (RS) blood flow in a porcine model of increased IAP. Seven domestic swine were anesthetized with pentobarbital and maintained with isoflurane. Swan-Ganz and femoral arterial catheters were placed for measurement of mean arterial pressure (MAP), cardiac output (CO), and pulmonary capillary wedge pressure (PCWP). A midline incision was performed for placement of laser flow probe on the RS and for placement of catheters to raise and measure IAP. Intra-abdominal pressure was then increased by installation of lactated ringers (LRs) into the peritoneum. Mean arterial pressure was maintained throughout the procedure with intravenous LR. Hemodynamics and RS blood flow data were obtained at baseline, 10, 20, 30, and 40 mm Hg IAP. Analysis of data was done by paired t-test with level of significance at P less than 0.05 and linear regression. Rectus sheath blood flow was significantly reduced at all pressure levels when compared to baseline and negatively correlated (r = -0.82) with increasing IAP. Since indices of systemic perfusion were maintained with increasing IAP, the decreased RS blood flow is most likely due to increased compartmental pressure within the abdomen.

Cardiovascular adaptation during simulated microgravity: lower body negative pressure to counter orthostatic hypotension.

The cardiovascular function is one of the main functions disturbed by microgravity. It is particularly affected by the astronaut's return to Earth, where one of the symptoms of the cardiovascular adaptation syndrome is orthostatic hypotension; the clinical consequence can be presyncopal state or a syncope. Lower body negative pressure (LBNP) is intended to stimulate the venous system of the lower limbs. Studies performed in the U.S. have shown that LBNP constitutes an efficient countermeasure, but this approach is impractical because 4 to 6 h/d of application are required. Five volunteers took part in two recent antiorthostatic bed rest experiments for 30 days. In the first experiment, three subjects were submitted to several sessions of LBNP per day and two others were controls; in the second, the LBNP group of the first experiment became control and vice versa. Two orthostatic investigations were performed: 5 d before bed rest; and at the end of the 30-d bed rest period. The results showed that: 1) when the subjects were controls, a high orthostatic hypotension post bed rest with three syncopes and one presyncopal state during the first minutes of the tilt test appeared; 2) when the subjects were submitted to LBNP sessions, no orthostatic hypotension was noted. These two experiments proved the beneficial effects of the LBNP as a countermeasure against orthostatic hypotension.