Significance of intraabdominal compartment pressures following TRAM flap breast reconstruction and the correlation of results

Abdominal wall closure after transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction is often performed under considerable tension and may theoretically cause a component of abdominal compartment syndrome. This prospective study examined intraabdominal pressure after TRAM reconstruction and correlated the findings with clinical course and outcome. All patients who underwent pedicled TRAM flap breast reconstruction from November of 1999 to December of 2000 (n = 77) were included and compared with non-operative controls (n = 24). Intraabdominal pressures were measured indirectly using the urinary catheter in the postanesthesia care unit on postoperative days 1 and 2. Outcome measures included vital signs, urinary output, net 24-degree fluid balance, and complications. The preoperative variables were age, body mass index, parity, and presence of an epidural. For statistical analysis, the TRAM patients were divided into three groups on the basis of type of closure (bipedicle, unipedicle, and mesh), which were compared by analysis of variance. A multivariate logistic regression was performed to identify risk factors for patients with intraabdominal pressures ≥20 mmHg who were thought to have a component of abdominal compartment syndrome. The incidence of complications was compared by chi-square, with statistical significance determined for p < 0.05. Average intraabdominal pressures were significantly higher in the bipedicled TRAM (14.1 mmHg) and unipedicle TRAM (9.9 mmHg) groups when compared with the mesh group (5 mmHg) and controls (3.7 mmHg; p < 0.001). Increased intraabdominal pressure was transient and peaked on postoperative day 1. Elevated pressure was associated with decreased urinary output, decreased net fluid balance, and increased respiratory rate. Patients with intraabdominal pressures ≥20 mmHg (n = 10) had a higher incidence of complications (60 percent) compared with patients who had pressures <20 mmHg (18 percent; p < 0.05). Elevated intraabdominal pressures were strongly associated with donor-site and general complications. Positive predictive factors for elevated pressure included body mass index and type of closure (bipedicled or bilateral). Multiple pregnancies seemed to have a protective effect. A transient component of abdominal compartment syndrome does exist after TRAM flap breast reconstruction. Bipedicle closure, nulliparous women, and increased body mass index were risk factors for elevated intraabdominal pressures. Tension-free mesh closure seemed to have a protective effect. Symptomatic trends and certain complications were associated with, and possibly explained by, an elevated intraabdominal pressure.