Objectives: To determine relationship of intra-abdominal pressure to central obesity and the comorbidity of obesity.
Design: Non-randomized, prospective.
Setting: University hospital, operating room.
Subjects: Eighty-four anaesthetized consecutive patients prior to gastric bypass for morbid obesity and five non-obese patients before colectomy for ulcerative colitis.
Main outcome measures: Weight, body mass index (BMI), co-morbid history, sagittal abdominal diameter, waist:hip (W:H) ratio and urinary bladder pressure, as an estimate of intra-abdominal pressure.
Results: Urinary bladder pressure was greater in the obese than the non-obese (18 +/- 0.7 vs. 7 +/- 1.6 cm H2O, P < 0.001), correlated with sagittal abdominal diameter (r = +0.67, P < 0.001) and was greater (P < 0.05) in patients with, than those without, morbidity probably (hypoventilation, gastroesophageal reflux, venous stasis, stress incontinence, incisional hernia) or possibly (hypertension, diabetes) due to increased abdominal pressure. W:H ratio correlated with urinary bladder pressure in men (r = +0.6, P < 0.05) but not women (r = -0.3).
Conclusions: Increased sagittal abdominal diameter was associated with increased intraabdominal pressure which contributed to obesity-related comorbidity. W:H ratio was not a reliable indicator of intra-abdominal pressure for women who often have both peripheral and central obesity. Further studies are needed to evaluate the relationship between intra-abdominal pressure and Type II diabetes and hypertension.