Truth or Myth: Intraabdominal Pressure Increases in the Lithotomy Position.

Abstract Study Objective To determine if there were differences in intraabdominal pressure (IAP) in supine, low lithotomy and high lithotomy positions. Design Prospective cohort study. Setting University medical center. Patients 29 women undergoing surgery for prolapse or stress incontinence. Interventions Relevant medial history, including the Pelvic Organ Prolapse Quantification (POP-Q) stage, BMI, and airway grade (Mallampati score), was abstracted from patients’ medical charts. IAP was measured in cmH2O on the day of their surgery prior to induction of general or intravenous anesthesia using a T-doc air charged urodynamic catheter placed in a patient's vagina (for patients with incontinence) or rectum (for patients with prolapse). Measurements and Main Results IAP was measured in three positions: supine (legs at 0 degrees), low lithotomy (legs in Yellowfin stirrups at 45 degrees), and high lithotomy (90 degrees). Mean ± SD IAP for the group in the supine position was 18.6 ± 7.6 cmH2O, low lithotomy 17.7 ± 6.6 cmH2O, and high lithotomy 17.1 ± 6.3 cmH2O. In the same women, there was a significant decrease in IAP from supine to high lithotomy positions, with mean difference of 1.4 cmH2O ± 3.7, p=0.05. Likewise, there was a significant, though smaller, decrease in mean IAP when moving from supine to low lithotomy in the same woman (mean decrease of 0.9 cmH2O ±1.5, p=0.004). Neither change is clinically significant based on prior research that suggests 5 cmH2O is a clinically significant change. Conclusion Placing patients’ legs in low or high lithotomy position does not result in a clinically significant increase in IAP. Therefore, surgeons and anesthesiologists can consider positioning patients’ lower extremities in stirrups while patients are awake to minimize discomfort and possibly reduce the risk of nerve injuries.