Friction, Trigonometry, and Newton’s Laws: All About Trendelenburg Position

Abstract Background Within the last decade, robotically-assisted laparoscopic prostatectomy (RALP) has become the standard for treating localized prostate cancer, causing a revival of the 45° Trendelenburg position. In this pilot study we investigated effects of Trendelenburg position on hemodynamics and cerebral oxygenation in patients undergoing RALP. Methods We enrolled 58 patients undergoing RALP and 22 patients undergoing robot-assisted partial nephrectomy (RAPN) (control group) in our study. Demographic patient data and intraoperative parameters including cerebral oxygenation and cerebral hemodynamics were recorded for all patients. Cerebral function was also assessed pre- and postoperatively via the Mini Mental Status (MMS) exam. Changes in parameters during surgery were modelled by a mixed effects model; changes in the MMS result were evaluated using the Wilcoxon signed rank test. Results Preoperative assessment of patient characteristics, standard blood values and vital parameters revealed no difference between the two groups. Conclusions Applying a 45° Trendelenburg position causes no difference in postoperative brain function, and does not alter cerebral oxygenation during a surgical procedure lasting up to 5 h. Further studies in larger patient cohorts will have to confirm these findings. Trial registration German Clinical Trial Registry; DRKS00005094; Registered 12th December 2013—Retrospectively registered; https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00005094.

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Addition to “Revised Formulation of Fick’s, Fourier’s, and Newton’s Laws for Spatially Varying Linear Transport Coefficients”

ACS Omega ◽

10.1021/acsomega.0c02856 ◽

2020 ◽

Vol 5 (51) ◽

pp. 33484-33487

Author(s):

You-Yeon Won ◽

Doraiswami Ramkrishna

Keyword(s):

Transport Coefficients ◽

Linear Transport ◽

Newton’S Laws ◽

Spatially Varying

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Effect of pressure-controlled ventilation-volume guaranteed mode combined with individualized positive end-expiratory pressure on respiratory mechanics, oxygenation and lung injury in patients undergoing laparoscopic surgery in Trendelenburg position

Journal of Clinical Monitoring and Computing ◽

10.1007/s10877-021-00750-9 ◽

2021 ◽

Author(s):

Jianli Li ◽

Saixian Ma ◽

Xiujie Chang ◽

Songxu Ju ◽

Meng Zhang ◽

...

Keyword(s):

Laparoscopic Surgery ◽

Lung Injury ◽

Respiratory Mechanics ◽

Lung Mechanics ◽

Trial Registry ◽

Positive End Expiratory Pressure ◽

Clinical Trial Registry ◽

Trendelenburg Position ◽

Pressure Controlled Ventilation ◽

Pressure Controlled

AbstractThe study aimed to investigate the efficacy of PCV-VG combined with individual PEEP during laparoscopic surgery in the Trendelenburg position. 120 patients were randomly divided into four groups: VF group (VCV plus 5cmH2O PEEP), PF group (PCV-VG plus 5cmH2O PEEP), VI group (VCV plus individual PEEP), and PI group (PCV-VG plus individual PEEP). Pmean, Ppeak, Cdyn, PaO2/FiO2, VD/VT, A-aDO2 and Qs/Qt were recorded at T1 (15 min after the induction of anesthesia), T2 (60 min after pneumoperitoneum), and T3 (5 min at the end of anesthesia). The CC16 and IL-6 were measured at T1 and T3. Our results showed that the Pmean was increased in VI and PI group, and the Ppeak was lower in PI group at T2. At T2 and T3, the Cdyn of PI group was higher than that in other groups, and PaO2/FiO2 was increased in PI group compared with VF and VI group. At T2 and T3, A-aDO2 of PI and PF group was reduced than that in other groups. The Qs/Qt was decreased in PI group compared with VF and VI group at T2 and T3. At T2, VD/VT in PI group was decreased than other groups. At T3, the concentration of CC16 in PI group was lower compared with other groups, and IL-6 level of PI group was decreased than that in VF and VI group. In conclusion, the patients who underwent laparoscopic surgery, PCV-VG combined with individual PEEP produced favorable lung mechanics and oxygenation, and thus reducing inflammatory response and lung injury.Clinical Trial registry: chictr.org. identifier: ChiCTR-2100044928

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