1984 THE EFFECT OF PRONE-FLEXED POSITIONING ON AIRWAY PRESSURES DURING PERCUTANEOUS NEPHROLITHOTOMY (PCNL)
Bibliographic record
Abstract
You have accessJournal of UrologyStone Disease: SWL, Ureteroscopy or Percutaneous Stone Removal (IV)1 Apr 20131984 THE EFFECT OF PRONE-FLEXED POSITIONING ON AIRWAY PRESSURES DURING PERCUTANEOUS NEPHROLITHOTOMY (PCNL) Kirsten Foell, Michael Ordon, Andrea Lantz, Kenneth T Pace, and R John D'A Honey Kirsten FoellKirsten Foell Toronto, Canada More articles by this author , Michael OrdonMichael Ordon Toronto, Canada More articles by this author , Andrea LantzAndrea Lantz Toronto, Canada More articles by this author , Kenneth T PaceKenneth T Pace Toronto, Canada More articles by this author , and R John D'A HoneyR John D'A Honey Toronto, Canada More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2403AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The prone-flexed position (PFP) for PCNL involves 40-60 degree flexion of the lumbar spine and 15 degree flexion at the knees. The advantages over the prone position (PP), as shown in one of our studies involving CT measurements, include widening of the space between the 12th rib and iliac crest, increased distance between the tract and the spleen or liver, lowering of the kidneys relative to the ribs, and shortening of the skin-to-stone distance. However, urologists unfamiliar with the PFP have questioned the effect of abdominal compression on airway pressure and ventilation. The objectives of this study were to quantify the changes in peak airway pressure (PAP) in the supine (SP), PP and PFP, and to determine the relationship between abdominal girth, body mass index (BMI) and PAP. METHODS Measurements involving consecutive patients undergoing PCNL in the PFP were prospectively recorded from Mar. to Oct. 2012. After intubation and muscle paralysis, the PAP and positive end-expiratory pressure (PEEP) were recorded in the SP, PP, and PFP. The PAPs (after subtracting PEEP) across the 3 positions for each patient were compared with repeated measure ANOVA. The paired t-test was used to compare the differences between SP and PFP across obese (BMI>30) and non-obese patients. To assess if abdominal girth was a predictor of change in PAP from SP to PFP, linear regression was utilized. RESULTS 42 patients (71% male, 29% female) were included. All PAPs were <35 cmH2O. The mean PAP was significantly higher in the PFP (20.5±0.7 cmH2O) than PP (17.2±0.6 cmH2O, p<0.001), which was higher than in the SP (15.4±0.6 cmH2O, p<0.001). The mean BMI was 28.3±5.2 kg/m2, and abdominal girth was 101±12 cm. The mean change in PAP when moving from the SP to PFP did not differ significantly in the obese (n=15) vs. non-obese (n=27) population (p=0.21). Abdominal girth was not a significant predictor of the change in PAP from SP to PFP (linear regression, p=0.23), however, girth was a significant predictor of elevated PAP in the PFP (p=0.024). Importantly, none of the patients required conversion out of the PFP for anesthetic or other reasons. CONCLUSIONS The airway pressures experienced in the prone-flexed position are significantly higher than when prone or supine, particularly in those with large abdominal girths. However, this elevation is not clinically significant, as all airway pressures remained <35 cmH2O and no patients required conversion to an alternate position. Given the anatomical and surgical advantages, prone-flexed remains our preferred position for PCNL and is safe, even in obese patients. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e814 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kirsten Foell Toronto, Canada More articles by this author Michael Ordon Toronto, Canada More articles by this author Andrea Lantz Toronto, Canada More articles by this author Kenneth T Pace Toronto, Canada More articles by this author R John D'A Honey Toronto, Canada More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.011 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".