You have accessJournal of UrologyStone Disease: Evaluation II1 Apr 2015MP80-13 DOES THE PEAK INSPIRATORY PRESSURE INCREASE IN THE PRONE POSITION? AN ANALYSIS RELATED TO BMI. Michael Siev, Piruz Motamedinia, David Leavitt, David Hoenig, Arthur Smith, and Zeph Okeke Michael SievMichael Siev More articles by this author , Piruz MotamediniaPiruz Motamedinia More articles by this author , David LeavittDavid Leavitt More articles by this author , David HoenigDavid Hoenig More articles by this author , Arthur SmithArthur Smith More articles by this author , and Zeph OkekeZeph Okeke More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.2849AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Percutaneous nephrolithotomy (PCNL) is performed most commonly in the prone position to facilitate access to the renal collecting system. There is concern that the prone position, especially in obese patients, results in negative effects on ventilation, due to restriction of chest compliance and respiratory mechanics. This study analyzes the change in airway resistance between supine and prone positioning of patients undergoing PCNL. METHODS In this IRB-approved study, between May and October 2014, we retrospectively reviewed 41 patients who underwent prone PCNL while all intraoperative respiratory parameters were continuously recorded. Peak inspiratory pressure (PIP) was selected as a marker of airway resistance and respiratory compliance, and was assessed in supine position, 1 minute after being turned prone (early prone) and at the end of the case (late prone). Results were stratified based on BMI and data were compared using the paired t-test with p < 0.05 considered significant. RESULTS Out of 41 cases, 15 (37%) were obese (BMI ≥30). For non-obese patients, average BMI was 23.5, and for obese patients, average BMI was 41.6. In non-obese patients, average PIP was 17.46, 18.10 and 17.90 cm H2O in the supine, early prone and late prone positions respectively; for obese patients average PIP was 23.97, 26.13 and 23.73 cm H2O. There was a statistically significant difference in average PIP between obese and non-obese patients in all 3 positions (p<0.0001, p<0.0001 and p=0.0009 respectively). There was also a statistically significant change in PIP from the supine to early prone position (p=0.03) in the obese cohort, but there was no significant difference between supine and late prone position (p=0.90). There was no statistically significant difference between any positions in non-obese patients (p=0.16 and p=0.83 respectively). CONCLUSIONS Changes in positioning do not affect PIP in non-obese patients. Though there is a statistically significant increase in airway resistance in obese patients, this occurs with initial positioning and PIP normalizes to supine levels by the end of the case. Thus, it appears that the negative effects of positioning on airway resistance and respiratory compliance in obese patients are transient, and that prone positioning for PCNL in obese patients remains a safe and viable option. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e1024 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Michael Siev More articles by this author Piruz Motamedinia More articles by this author David Leavitt More articles by this author David Hoenig More articles by this author Arthur Smith More articles by this author Zeph Okeke More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...