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Objective: To compare the clinical outcomes of control of drainage volume through either elevating the drainage height or tilting the head down in a supine position for the management of cerebrospinal fluid leakage (CSFL) following posterior lumbar surgery., Methods: A retrospective analysis was conducted to review the data of patients who underwent lumbar spine surgery at a single hospital over a 4-year period from January 2020 to December 2023. Postoperative CSFL and complications were recorded. All patients with CSFL were managed with bed rest, a 20-30° head-down tilt position, or a drainage system elevated by 10 cm, along with subfascial drains, for a duration of 3 days. The clinical outcomes of drainage volume control were compared between the elevation of the drainage system and the head-down tilt position in the supine posture., Results: The incidence of CSFL after lumbar surgeries was 1.2% (84 out of 7,284 cases). None of the CSFL patients experienced significant complications or required reoperation. When compared to the traditional Trendelenburg position, elevating the drainage height reduced the incidence of headache and dizziness, as well as shortened the time to ambulation, postoperative defecation time, and postoperative hospital stay, with statistically significant differences (p < 0.05)., Conclusion: Postoperative drainage volume control using the Trendelenburg position or elevation of the drainage height is both safe and effective for the management of CSFL. The method involving a 10 cm elevation of the drainage system appears to be an easier and more clinically acceptable approach for the nursing care of CSFL following posterior lumbar surgery., Competing Interests: Declarations Ethics approval and consent to participate This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Medical Ethics Committee of Xinqiao Hospital, Army Medical University ((Reference number 2024-YD228-01). Written informed consent was obtained from all the participants. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Background: Orthostatic intolerance occurs following immobilization in patients on Earth and in astronauts after spaceflight. Head-down tilt bedrest is a terrestrial model for weightlessness and induces orthostatic intolerance. We hypothesized that lower-body negative pressure (LBNP) or cycling followed by wearing venous constrictive thigh cuffs mitigates orthostatic intolerance after head-down tilt bedrest., Methods and Results: We enrolled 47 healthy individuals (20 women, 35±9 years) to a 30-day strict head-down tilt bedrest study. During bedrest, they were assigned to 6 hours of 25 mm Hg LBNP (n=12) per day and 1 hour of supine cycling followed by 6 hours of venous constriction through thigh cuffs 6 days per week (n=12), 6 hours of daily upright sitting (positive control, n=11), or no countermeasure (negative control, n=12). We measured orthostatic tolerance as the time to presyncope during 80° head-up tilt testing with incremental LBNP before and immediately after bedrest. We determined plasma volume with carbon monoxide rebreathing before and at the end of bedrest. After bedrest, orthostatic tolerance decreased 540±457 seconds in the control group, 539±68 seconds in the cycling group, 217±379 seconds in the LBNP group, and 289±89 seconds in the seated group ( P <0.0001 time point, P =0.009 for group differences). Supine and upright heart rate increased in all groups following bedrest. Plasma volume was only maintained in the cycling group but decreased in all others (interaction countermeasure×time point P <0.0001)., Conclusions: Six hours of moderate LBNP training was as effective as sitting in attenuating orthostatic intolerance after 30 days of head-down tilt bedrest. Daily cycling exercise followed by 6 hours of wearing venous constrictive thigh cuffs, while maintaining plasma volume, did not improve orthostatic tolerance., Registration: URL: https://www.bfarm.de/EN; Identifiers: DRKS00027643 and DRKS00030848.

Rationale: The effect of the head position as a non-pharmacological therapy on acute ischaemic stroke (AIS) remains inconclusive. Our recent Head dOwn-Position for acutE moderate ischaemic Stroke with large artery atherosclerosis (HOPES 2) suggested the safety, feasibility and potential benefit of the head-down position (HDP) in AIS., Aim: To investigate the benefit of HDP in acute moderate ischaemic stroke patients with large artery atherosclerosis (LAA)., Sample Size Estimates: Based on a two-sided 0.05 level of significance, 600 patients are expected to yield the superiority hypothesis with 80% power, stratified by age, sex, history of diabetes, baseline systolic blood pressure, location of index vessel, National Institutes of Health Stroke Scale Score at randomisation, onset to randomisation time, progression to moderate neurological deficit due to early neurological deterioration and degree of responsible vessel stenosis., Design: Head dOwn-Position for acutE moderate ischaemic Stroke with large artery atherosclerosis(HOPES 3) is a prospective, randomised, open-label, blinded endpoint and multicentre study. Eligible patients who had an ischaemic stroke will be randomly assigned (1:1) into the HDP group receiving -20° Trendelenburg plus standard medical care in compliance with national guidelines, or control group only receiving standard medical care in compliance with national guidelines., Outcome: The primary outcome is favourable functional outcome, defined as modified Rankin Scale 0-2 at 90 days. Safety outcomes are HDP-related adverse events. All outcomes will have blinded assessment and will be analysed on the intention-to-treat basis., Conclusions: The results of HOPES 3 will provide evidence for the effect of HDP in acute moderate ischaemic stroke patients with LAA within 24 hours of onset or in patients with progression from mild neurological deficit within 24 hours., Trial Registration Number: NCT06010641., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Well-leg compartment syndrome (WLCS) can occur due to compression and lower limb circulation disturbances caused by the surgical position during the procedure. Although rare, with an incidence of 1 in 3500 surgeries performed in the lithotomy position, it can lead to serious complications. Therefore, prevention and early diagnosis are critical. Symptoms of WLCS, such as leg pain, swelling, paresthesia, and serum creatine kinase (CK) levels are useful for diagnosis. This study aimed to investigate the risk factors for postoperative CK elevation in laparoscopic or robot-assisted colorectal cancer surgery performed in the lithotomy-Trendelenburg position., Methods: Postoperative CK levels were measured in 178 patients who underwent laparoscopic or robot-assisted colorectal cancer surgery between February 2022 and March 2023. We compared patient backgrounds, short-term outcomes, and thigh/calf circumferences between patients with CK levels ≥ 250 (n = 62) and those with CK levels < 250 (n = 116). We investigated risk factors for elevated CK levels using both univariate and multivariate analyses., Results: Four patients with CK levels of 22405 U/L, 4685 U/L, 4050 U/L, and 3824 U/L reported symptoms, which improved with conservative treatment. The following independent prognostic factors were identified by multivariate analysis: male sex (odds ratio [OR], 4.403; 95% CI, 1.960 to 9.892), rectal surgery (OR, 2.779; 95% CI, 1.249 to 6.184), continuous head-down position duration ≥ 180 min (OR, 3.523; 95% CI, 1.552 to 7.997), and preoperative calf circumference ≥ 33 cm (OR, 2.482; 95% CI, 1.154 to 5.339)., Conclusions: Risk factors for CK elevation after colorectal cancer surgery in the lithotomy position include male sex, rectal surgery, an extended continuous head-down position without position changes, and a larger preoperative calf circumference. This study highlights the potential importance of intraoperative position changes every 3 h for preventing elevated CK levels, although the preventive effect was not specifically examined., (© 2024. The Author(s).)

Aim: To identify factors influencing the Trendelenburg angle required during laparoscopic gynecological surgery., Methods: Patients who underwent laparoscopic surgery at a single university hospital between May 1, 2019, and March 31, 2021 were enrolled. Data were extracted from the medical records, while magnetic resonance imaging scans and all laparoscopic surgery videos were retrospectively reviewed to assess the presence of the small intestine in the pelvic cavity as well as the adhesions at each site. Groups with and without the small intestine in the pelvic cavity, and those requiring a Trendelenburg angle above or below 13° were compared., Results: In total, 219 patients were examined. The Trendelenburg angle was significantly higher (p = 0.004), while a significant increase in ovarian adhesions was observed (p = 0.033; odds ratio [OR], 2.30; 95% confidence interval [CI], 1.05-5.01) in the group without the presence of the small intestine in the pelvic cavity. Furthermore, the group requiring a Trendelenburg angle of ≥13° had significantly thicker subcutaneous fat (p = 0.044) and more ileal adhesions (p = 0.040, OR, 1.82; 95% CI, 1.03-3.23) than the group with an angle of <13°., Conclusion: Cases of ileal adhesions or thick subcutaneous fat are more likely to require a Trendelenburg angle of ≥13°. Therefore, Trendelenburg complications should be considered in this group. In addition, ovarian adhesions make it more difficult to exclude the small intestine from the small pelvic cavity, and may be associated with endometriosis., (© 2024 Japan Society of Obstetrics and Gynecology.)

Background: Postoperative acute kidney injury (PO-AKI) is a frequent complication after surgery. Various tools have been proposed to identify patients at high risk for AKI, including preoperative serum creatinine or estimated glomerular filtration rate (eGFR), urinary cell cycle arrest, and tubular damage biomarkers; however, none of these can appropriately assess AKI risk before surgery. Renal functional reserve (RFR) screened by the Doppler-derived intraparenchymal renal resistive index variation (IRRIV) test has been proposed to identify patients at risk for AKI before a kidney insult. IRRIV test has been developed in healthy individuals and previously investigated in cardiac surgery patients. This study aims to evaluate the value of the IRRIV test in identifying PO-AKI among patients undergoing robotic abdominal surgery in the Trendelenburg position for pelvic oncological disease., Methods: We performed a prospective, double-blinded, observational study. Preoperative baseline renal function and RFR were assessed in 53 patients with baseline eGFR >60 mL/min/1.73 m2, undergoing robotic surgery in the Trendelenburg position for pelvic oncological disease. The capability of Doppler-derived RFR in predicting PO-AKI was investigated with the area under the receiver operating characteristic curve (ROC-AUC)., Results: Approximately 15.1% of patients developed AKI within the first 3 postoperative days. Thirty-one (58.5%) patients had a physiologic delta-RRI (ie, ≥0.05), while 22 (41.5%) patients did not. The ROC-AUC for PO-AKI was 0.85 (95% confidence interval [CI], 0.74-0.97; P = .007) for serum creatinine, 0.84 (95% CI, 0.71-0.96; P = .006) for eGFR, and 0.84 (95% CI, 0.78-0.91; P = .017) for delta-RRI. When combined with eGFR, the ROC-AUC for delta-RRI was 0.95 (95% CI, 0.9-1)., Conclusions: Our findings show that the preoperative assessment of Doppler-derived RFR combined with baseline renal function improves the capability of identifying patients at high risk for PO-AKI with eGFR >60 mL/min/1.73 m2 after robotic abdominal surgery in Trendelenburg position for pelvic oncological disease., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the International Anesthesia Research Society.)

Background: Tracheal intubation sometimes causes postoperative sore throat (POST) due to laryngeal damage. However, clinical observations suggest that the environment of the oral cavity may also affect POST., Objective: The purpose of this study was to investigate whether salivary pH in the oral cavity affects POST., Methods: After obtaining ethical approval, informed consent was obtained from all patients. Patients who underwent surgery in the supine position were enrolled as the control group. Patients who underwent laparoscopic surgery in the head-down position were enrolled as the intervention group. Immediately before both groups of patients were anaesthetised, expelled saliva was collected, and salivary pH was measured. Immediately postoperatively, the same measurement was carried out before the patient regained consciousness. The primary outcome was the change in salivary pH. The secondary outcome was POST. In our study, POST was defined as pharyngeal and swallowing pain in the glossopharyngeal and superior laryngeal nerves. The normal distribution of pH was tested using the Shapiro-Wilk test followed by analysis using repeated-measurements and one-way analysis of variance. Statistical significance was set at p < .05., Results: A total of 62 patients were enrolled, of whom two were excluded based on the exclusion criteria. Salivary pH in the intervention group was significantly lower than that in the control group. Five patients had POST in the intervention group, whereas none had POST in the control group had POST., Conclusion: Acidotic-shifted saliva is considered one of the causes of POST., (© 2024 John Wiley & Sons Ltd.)

Background/aim: Robot-assisted radical prostatectomy (RARP) has been widely adopted as the standard treatment for localized prostate cancer. RARP is safer and results in better oncological control than conventional open total prostatectomy. However, it has also been reported that acute kidney injury (AKI) can be caused by the use of carbon dioxide pneumoperitoneum and a steep Trendelenburg position. We investigated the incidence of AKI after RARP and its relationship with the Trendelenburg position angle., Patients and Methods: Seventy-seven patients underwent RARP at our institution. They were divided into two groups: Those in which a Trendelenburg position with the head down at 20 degrees was employed (group A) and those in which a Trendelenburg position with the head down at 25 degrees was used (group B). To detect AKI, the serum creatinine concentration was measured at the following four points: Prior to surgery, on postoperative day 0 (immediately after RARP), and on postoperative days 1 and 6 after RARP., Results: The incidence of AKI on POD 0 was lower in group B than in group A (p=0.0408). On POD 6, the renal function of all patients had improved to preoperative levels. Hypertension was a predictor of the incidence of AKI immediately after RARP., Conclusion: Although there was a significant Trendelenburg position angle-dependent difference in the incidence of AKI immediately after RARP, it was temporary. Hypertension is a predictor of AKI immediately after RARP. It is recommended that a 25-degree Trendelenburg position angle should be employed during RARP., (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Death from positional asphyxia occurs when the victim is found in a position that interferes with adequate breathing. We present an unusual case of a 67-yearold man who was found deceased trapped in a badger sett. The autopsy revealed marked congestion, cyanosis and a multitude of pinpoint hemorrhages in the face, neck and upper chest. Confluent scleral and conjunctival hemorrhage were observed and numerous petechial bleedings were found in the oral mucosa and within the reflected scalp. Death was attributed to positional asphyxia due to head-down position in a badger sett.

Prolonged bedrest provokes orthostatic hypotension and intolerance of upright posture. Limited data are available on the cardiovascular responses of older adults to head-up tilt following bedrest, with no studies examining the potential benefits of exercise to mitigate intolerance in this age group. This randomized controlled trial of head-down bedrest (HDBR) in 55- to 65-yr-old men and women investigated if exercise could avert post-HDBR orthostatic intolerance. Twenty-two healthy older adults (11 female) underwent a strict 14-day HDBR and were assigned to either an exercise (EX) or control (CON) group. The exercise intervention included high-intensity, aerobic, and resistance exercises. Head-up tilt-testing to a maximum of 15 minutes was performed at baseline (Pre-Bedrest) and immediately after HDBR (R1), as well as 6 days (R6) and 4 weeks (R4wk) later. At Pre-Bedrest, three participants did not complete the full 15 minutes of tilt. At R1, 18 did not finish, with no difference in tilt end time between CON (422 ± 287 s) and EX (409 ± 346 s). No differences between CON and EX were observed at R6 or R4wk. At R1, just 1 participant self-terminated the test with symptoms, while 12 others reported symptoms only after physiological test termination criteria were reached. Finishers on R1 protected arterial pressure with higher total peripheral resistance relative to Pre-Bedrest. Cerebral blood velocity decreased linearly with reductions in arterial pressure, end-tidal CO 2 , and cardiac output. High-intensity interval exercise did not benefit post-HDBR orthostatic tolerance in older adults. Multiple factors were associated with the reduction in cerebral blood velocity leading to intolerance.

Intraoperative physiologic changes related to the steep Trendelenburg position have been investigated with the widespread adoption of robot-assisted pelvic surgery (RAPS). However, the impact of the steep Trendelenburg position on postoperative complications remains unclear. We conducted a meta-analysis to compare RAPS to laparoscopic/open pelvic surgery with regards to the rates of venous thromboembolism (VTE), cardiac, and cerebrovascular complications. Meta-regression was performed to evaluate the influence of confounding risk factors. Ten randomized controlled trials (RCTs) and 47 non-randomized controlled studies (NRSs), with a total of 380,125 patients, were included. Although RAPS was associated with a decreased risk of VTE and cardiac complications compared to laparoscopic/open pelvic surgery in NRSs [risk ratio (RR), 0.59; 95% CI 0.51-0.72, p < 0.001 and RR 0.93; 95% CI 0.58-1.50, p = 0.78, respectively], these differences were not confirmed in RCTs (RR 0.92; 95% CI 0.52-1.62, p = 0.77 and RR 0.93; 95% CI 0.58-1.50, p = 0.78, respectively). In subgroup analyses of laparoscopic surgery, there was no significant difference in the risk of VTE and cardiac complications in both RCTs and NRSs. In the meta-regression, none of the risk factors were found to be associated with heterogeneity. Furthermore, no significant difference was observed in cerebrovascular complications between RAPS and laparoscopic/open pelvic surgery. Our meta-analysis suggests that the steep Trendelenburg position does not seem to affect postoperative complications and, therefore, can be considered safe with regard to the risk of VTE, cardiac, and cerebrovascular complications. However, proper individualized preventive measures should still be implemented during all surgeries including RAPS to warrant patient safety., (© 2021. The Author(s).)

Background: Intraoperative hypertension and blood pressure (BP) fluctuation are known to be associated with negative patient outcomes. During robotic lower abdominal surgery, the patient's abdominal cavity is filled with CO2, and the patient's head is steeply positioned toward the floor (Trendelenburg position). Pneumoperitoneum and the Trendelenburg position together with physiological alterations during anesthesia, interfere with predicting BP changes. Recently, deep learning using recurrent neural networks (RNN) was shown to be effective in predicting intraoperative BP. A model for predicting BP rise was designed using RNN under special scenarios during robotic laparoscopic surgery and its accuracy was tested., Methods: Databases that included adult patients (over 19 years old) undergoing low abdominal da Vinci robotic surgery (ovarian cystectomy, hysterectomy, myomectomy, prostatectomy, and salpingo-oophorectomy) at Soonchunhyang University Bucheon Hospital from October 2018 to March 2021 were used. An RNN-based model was designed using Python3 language with the PyTorch packages. The model was trained to predict whether hypertension (20% increase in the mean BP from baseline) would develop within 10 minutes after pneumoperitoneum., Results: Eight distinct datasets were generated and the predictive power was compared. The macro-average F1 scores of the datasets ranged from 68.18% to 72.33%. It took only 3.472 milliseconds to obtain 39 prediction outputs., Conclusions: A prediction model using the RNN may predict BP rises during robotic laparoscopic surgery., Competing Interests: The authors have declared that no competing interests exist.

Spaceflight associated neuro-ocular syndrome (SANS) is hypothesized to develop as a consequence of the chronic headward fluid shift that occurs in sustained weightlessness. We exposed healthy subjects (n = 24) to strict 6° head-down tilt bed rest (HDTBR), an analog of weightlessness that generates a sustained headward fluid shift, and we monitored for ocular changes similar to findings that develop in SANS. Two-thirds of the subjects received a daily 30-min exposure to artificial gravity (AG, 1 g at center of mass, ~0.3 g at eye level) during HDTBR by either continuous (cAG, n = 8) or intermittent (iAG, n = 8) short-arm centrifugation to investigate whether this intervention would attenuate headward fluid shift-induced ocular changes. Optical coherence tomography images were acquired to quantify changes in peripapillary total retinal thickness (TRT), retinal nerve fiber layer thickness, and choroidal thickness, and to detect chorioretinal folds. Intraocular pressure (IOP), optical biometry, and standard automated perimetry data were collected. TRT increased by 35.9 µm (95% CI, 19.9-51.9 µm, p < 0.0001), 36.5 µm (95% CI, 4.7-68.2 µm, p = 0.01), and 27.6 µm (95% CI, 8.8-46.3 µm, p = 0.0005) at HDTBR day 58 in the control, cAG, and iAG groups, respectively. Chorioretinal folds developed in six subjects across the groups, despite small increases in IOP. Visual function outcomes did not change. These findings validate strict HDTBR without elevated ambient CO 2 as a model for investigating SANS and suggest that a fluid shift reversal of longer duration and/or greater magnitude at the eye may be required to prevent or mitigate SANS., (© 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society. This article has been contributed to by US Government employees and their work is in the public domain in the USA.)

The aim of this study was to compare different end-tidal carbon dioxide (EtCO 2 ) levels to prevent postoperative nausea and vomiting (PONV) caused by increased intracranial pressure due to pneumoperitoneum and Trendelenburg position in gynaecological laparoscopic surgery. A total of 60 female patients aged 25-50 years who would undergo laparoscopic gynaecological surgery under general anaesthesia were randomised into two groups: group A (EtCO 2 : 26 - 35 mmHg, n  = 30) and group B (EtCO 2 : 36 - 45 mmHg, n  = 30). In both groups, ONSD and EtCO 2 of the patients were measured at baseline after anaesthesia induction ( T b ), at 5 min after pneumoperitoneum ( T PP5 ), and at 10 min intervals after Trendelenburg position ( T PP10 , T PP20 , T PP30 ). At 5 ( T D5 ) and 10 min ( T D10 ) after deflation, ONSD measurements were repeated. The incidence and severity of PONV of the patients, and antiemetic drugs used in both groups were assessed in the postoperative period. In the intraoperative follow-up periods, T PP5 and subsequent EtCO 2 values, as well as T PP10 and subsequent ONSD values, were significantly higher in group B and the incidence of nausea, the PONV scores and the incidence of rescue antiemetic use significantly lower in group A than in group B ( p <.001 for all). This result indicates that low EtCO 2 levels have beneficial effects on ICP and PONV in laparoscopic gynaecological operations.Impact statement What is already known on this subject? Laparoscopic gynaecologic surgery has been a more preferred technique. The incidence of postoperative nausea and vomiting (PONV) after laparoscopic gynaecologic surgery is remarkably high. In the prevention of PONV after gynaecologic laparoscopic surgery, single and multiple drug therapies and methods have been used. What the results of this study add? Postoperative nausea and vomiting caused by intracranial pressure (ICP) increase due to carbon dioxide pneumoperitoneum and Trendelenburg position in gynaecologic laparoscopic surgeries were decreased in the early postoperative period by low end-tidal carbon dioxide levels in the intraoperative period. It was shown that low end-tidal carbon dioxide levels have beneficial effects on ICP and PONV in laparoscopic gynaecologic operations. What the implications are of these findings for clinical practice and/or further research? This result indicates that low end-tidal carbon dioxide levels have beneficial effects on ICP and PONV in laparoscopic gynaecologic operations.

Background: Robot-assisted laparoscopic prostatectomy (RALP) frequently entails postoperative pulmonary complications (PPCs) due to the Trendelenburg position and pneumoperitoneum. Diaphragm thickening fraction (TF) as an imaging marker can offer the advantage of predicting respiratory outcomes. Therefore, we evaluated the effect of diaphragm TF on the occurrence of PPCs in RALP., Methods: We measured the preoperative thickness of the diaphragm at peak inspiration ( T pi ) and end expiration ( T ee ) using ultrasonography. Diaphragm TF was calculated as TF = ( T pi - T ee )/ T ee . A receiver operating characteristic (ROC) curve analysis of TF was performed. After dividing patients into two groups according to the optimal TF cut-off value, we compared the occurrence of PPCs between the groups. The predictivity of diaphragm TF for the occurrence of PPCs was evaluated., Results: Of 145 patients, 40 patients (27.6%) developed PPCs. Patients with PPCs had a significantly lower TF than those without PPCs (0.31 ± 0.09 vs. 0.39 ± 0.11, P < 0.001). In the ROC curve analysis, the optimal TF cut-off value was 0.28. The patients were divided into TF ≥ 0.28 group ( n = 114) and TF < 0.28 group ( n = 31). The incidence of PPCs was significantly higher in the TF < 0.28 group than in the TF ≥ 0.28 group (51.6% vs. 21.1%, P = 0.001). Diaphragm TF < 0.28 was associated with a higher incidence of PPCs than diaphragm TF ≥ 0.28 (odds ratio = 4.534, 95% confidence interval [1.763-11.658], P = 0.002)., Conclusion: Preoperative diaphragm TF < 0.28 was associated with an increased incidence of PPCs, suggesting that diaphragm TF as a prognostic imaging marker provides useful information on PPCs in RALP requiring the Trendelenburg position and pneumoperitoneum. Trial Registry Number . This trial is registered with KCT0005028., Competing Interests: All authors declared no competing interests., (Copyright © 2021 Jihion Yu et al.)

Purpose: Cardiovascular regulation during exercise, described using time series analysis, is expected to be attenuated after bed rest (BR) and this effect will be dampened by a reactive jumps countermeasure., Methods: Twenty subjects (29 ± 6 years, 23.6 ± 1.7 kg m -2 ) were tested on a cycle ergometer 9 days (BDC-9) before the beginning of BR as well as 2 (R + 2) and 13 days (R + 13) after the end of BR, applying moderate pseudo-random binary (PRBS) work rate changes. Heart rate (HR) and mean arterial blood pressure (mBP) were measured beat-to-beat and interpolated to 1 s intervals. HR and mBP were cross-correlated [CCF(HR-mBP)] during the PRBS. Eleven subjects participated in a reactive jump countermeasure (JUMP) during the BR period, the other part of the group served as control group (CTRL)., Results: In the CTRL group, significantly lower CCF(HR-mBP) values during BDC-9 were observed compared to R + 2 during the lags 20-25 s and significantly higher values during the lags - 39 s to - 35 s. In the JUMP group, significantly lower CCFs were only observed at R + 2 compared with BDC-9 during the lags 23 s and 24 s, whereas the CCFs for BDC-9 were significantly higher at several lags compared with R + 13., Conclusion: Attenuations in the regulation of the cardiovascular system during cycling exercise after BR were found in the CTRL group of the RSL study. Cardiovascular regulation in the JUMP group was improved compared to values before the beginning of BR, suggesting the effectiveness of the reactive jumps countermeasure to mitigate the deleterious effects of prolonged BR.

Background: Asymptomatic mastoid effusions have recently been observed in astronauts returning from long-term spaceflight. In hospitalized patients, mastoid effusion increases the risks for bacterial otitis and mastoiditis. We reasoned that cephalad fluid shifts during strict -6° head down tilt bed rest could reproduce space-flight associated mastoid effusion and that artificial gravity may reverse the response., Methods: The recent Artificial Gravity Bed Rest Study-European Space Agency study (AGBRESA) tested influences of artificial gravity during 60 days head down bed rest on a short-arm human centrifuge in healthy participants. The two intervention groups received daily artificial gravity with 30 minutes continuous artificial gravity or intermittent artificial gravity. A third group served as a control group and received no artificial gravity. We assessed cranial magnetic resonance images for mastoid effusions 1 day before bed rest, at days 14 and 52 of bed rest, and 3 days after bed rest., Results: None of the participants exhibited mastoid effusions before bed rest. Six participants showed mastoid effusions at bed rest day 14 (4 continuous, 2 intermittent, 0 control). Fifteen participants showed mastoid effusions at bed rest day 52 and 3 days after bed rest (7 continuous, 3 intermittent, 5 control)., Conclusions: Mastoid effusions commonly occur during strict head down tilt bed rest. The model can be applied to study the mechanisms and potential countermeasures for space flight-associated mastoid effusions. Formation of mastoid effusions during head down tilt bed rest is not prevented by daily 30 minutes short-arm intermittent or continuous centrifugation., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Abstract: New generation supraglottic airway devices are suitable for airway management in many laparoscopic surgeries. In this study, we evaluated and compared the ventilation parameters of the laryngeal mask airway-supreme (LM-S) and endotracheal tube (ETT) when a neuromuscular blocker (NMB) agent was not used during laparoscopic gynecological surgery. The second outcome was based on the evaluation of the surgical view because it may affect the surgical procedure.This was a randomized study that enrolled 100 patients between 18 and 65 years old with an ASA I-II classification. Patients were divided into 2 groups: Group ETT and Group LM-S. Standard anesthesia and ventilation protocols were administered to patients in each group. Ventilation parameters [airway peak pressure (Ppeak), mean airway pressure (Pmean), total volume, and oropharyngeal leak pressure] were recorded before, after, and during peritoneal insufflation and before desufflation, as well as after the removal of the airway device. Perioperative surgical view quality and the adequacy of the pneumoperitoneum were also recorded.The data of 100 patients were included in the statistical analysis. The Ppeak values in Group ETT were significantly higher in the second minute after airway device insertion. The Ppeak and Pmean values in Group ETT were significantly higher before desufflation and after removal of the airway device. No significant differences were found between the groups in terms of adequacy of the pneumoperitoneum or quality of the surgical view.The results of this study showed that gynecological laparoscopies can be performed without using a NMB. Satisfactory conditions for ventilation and surgery can be achieved while sparing the use of muscle relaxants in both groups despite the Trendelenburg position and the pneumoperitoneum of the patients, which are typical for laparoscopic gynecological surgery. The results are of clinical significance because they show that the use of a muscle relaxant is unnecessary when supraglottic airways are used for these surgical procedures., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Artificial gravity is a potential countermeasure to attenuate effects of weightlessness during long-term spaceflight, including losses of muscle mass and function, possibly to some extent attributable to disturbed neuromuscular interaction. The 60-day AGBRESA bed-rest study was conducted with 24 participants (16 men, 8 women; 33 ± 9 years; 175 ± 9 cm; 74 ± 10 kg; 8 control group, 8 continuous (cAG) and 8 intermittent (iAG) centrifugation) to assess the impact of bed rest with or without daily 30-min continuous/intermittent centrifugation with 1G at the centre of mass. Fasting blood samples were collected before and on day 6, 20, 40 and 57 during 6° head-down tilt bed rest. Concentrations of circulating markers of muscle wasting (GDF-8/myostatin; slow skeletal muscle troponin T; prostaglandin E2), neurotrophic factors (BDNF; GDNF) and C-terminal Agrin Fragment (CAF) were determined by ELISAs. Creatine kinase activity was assessed by colorimetric enzyme assay. Repeated-measures ANOVAs were conducted with TIME as within-subject, and INTERVENTION and SEX as between-subject factors. The analyses revealed no significant effect of bed rest or sex on any of the parameters. Continuous or intermittent artificial gravity is a safe intervention that does not have a negative impact of the neuromuscular secretome., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Aboard the International Space Station (ISS), astronauts must adapt to altered vestibular and somatosensory inputs due to microgravity. Sensorimotor adaptation on Earth is often studied with a task that introduces visuomotor conflict. Retention of the adaptation process, known as savings, can be measured when subjects are exposed to the same adaptive task multiple times. It is unclear how adaptation demands found on the ISS might interfere with the ability to adapt to other sensory conflict at the same time. In the present study, we investigated the impact of 30 days' head-down tilt bed rest combined with elevated carbon dioxide (HDBR + CO 2 ) as a spaceflight analog on sensorimotor adaptation. Eleven subjects used a joystick to move a cursor to targets presented on a computer screen under veridical cursor feedback and 45° rotated feedback. During this NASA campaign, five individuals presented with optic disk edema, a sign of spaceflight-associated neuro-ocular syndrome (SANS). Thus, we also performed post hoc exploratory analyses between subgroups who did and did not show signs of SANS. HDBR + CO 2 had some impact on sensorimotor adaptation, with a lack of savings across the whole group. SANS individuals showed larger, more persistent after-effects, suggesting a shift from relying on cognitive to more implicit processing of adaptive behaviors. Overall, these findings suggest that HDBR + CO 2 alters the way in which individuals engage in sensorimotor processing. These findings have important implications for missions and mission training, which require individuals to adapt to altered sensory inputs over long periods in space. NEW & NOTEWORTHY This is the first bed rest campaign examining sensorimotor adaptation and savings in response to the combined effect of HDBR + CO2 and to observe signs of spaceflight-associated neuro-ocular syndrome (SANS) in HDBR participants. Our findings suggest that HDBR + CO2 alters the way that individuals engage in sensorimotor processing. Individuals who developed signs of SANS seem to rely more on implicit rather than cognitive processing of adaptive behaviors than subjects who did not present signs of SANS.

Background: The present study investigated the association between Postoperative Cognitive Dysfunction (POCD) and increased serum S100B level after Robotic-Assisted Laparoscopic Radical Prostatectomy (RALRP)., Methods: The study included 82 consecutive patients who underwent RALRP. Serum S100B levels were determined preoperatively, after anesthesia induction, and at 30 minutes and 24 hours postoperatively. Cognitive function was assessed using neuropsychological testing preoperatively and at 7 days and 3 months postoperatively., Results: Twenty-four patients (29%) exhibited POCD 7 days after surgery, and 9 (11%) at 3 months after surgery. Serum S100B levels were significantly increased at postoperative 30minutes and 24 hours in patients displaying POCD at postoperative 7 days (p = 0.0001 for both) and 3 months (p = 0.001 for both) compared to patients without POCD. Duration of anesthesia was also significantly longer in patients with POCD at 7 days and 3 months after surgery compared with patients without POCD (p = 0.012, p = 0.001, respectively), as was duration of Trendelenburg (p = 0.025, p = 0.002, respectively). Composite Z score in tests performed on day 7 were significantly correlated with duration of Trendelenburg and duration of anesthesia (p = 0.0001 for both)., Conclusions: S100B increases after RALRP and this increase is associated with POCD development. Duration of Trendelenburg position and anesthesia contribute to the development of POCD., Trial Registry Number: Clinicaltrials.gov (N° NCT03018522)., (Copyright © 2020 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.)

Biomarkers of cartilage metabolism are sensitive to changes in the biological and mechanical environment and can indicate early changes in cartilage homeostasis. The purpose of this study was to determine if a daily locomotion replacement program can serve as a countermeasure for changes in cartilage biomarker serum concentration caused by immobilization. Ten healthy male subjects (mean ± 1 standard deviation; age: 29.4 ± 5.9 years; body mass: 77.7 ± 4.1 kg) participated in the crossover 5-day bed rest study with three interventions: control (CON), standing (STA), and locomotion replacement training (LRT). Serum samples were taken before, during, and after bed rest. Biomarker concentrations were measured using commercial enzyme-linked immunosorbent assays. Cartilage oligomeric matrix protein (COMP) levels after 24 hours of bed rest decreased independently of the intervention (-16.8% to -9.8%) and continued to decrease until 72 hours of bed rest (minimum, -23.2% to -20.6%). LRT and STA did not affect COMP during bed rests (P = .056) but there was a strong tendency for a slower decrease with LRT (-9.4%) and STA (-11.7%) compared with CON (-16.8%). MMP-3 levels decreased within the first 24 hours of bed rest (CON: -22.3%; STA: -14.7%; LRT: -17%) without intervention effect. Both COMP and MMP-3 levels recovered to baseline levels during the 6-day recovery period. MMP-1, MMP-9, and TNF-α levels were not affected by immobilization or intervention. COMP and MMP-3 are mechano-sensitive cartilage biomarkers affected by immobilization, and simple interventions such as standing upright or LRT during bed rest cannot prevent these changes. Clinical significance: simple locomotion interventions cannot prevent cartilage biomarker change during bed rest., (© 2020 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.)

Otorrhagia is generally associated with basilar skull fractures or diving accidents. In routine forensic medical practice, an accurate knowledge of the etiology of otorrhagia may have a key role to distinguish between traumatic and atraumatic causes and accidental, homicidal, or suicidal manners. The authors present the case of an unusual cause of atraumatic otorrhagia occurred in an elderly farmer found dead in a barn. He remained entrapped in a narrow tunnel created by some hay bales. The autopsy findings revealed only an intense polyvisceral congestion and subpleural petechiae, with no signs of traumatic injuries and no fractures of skull base or temporal pyramid. The cause of death was determined to be positional asphyxia, and the manner of death was deemed accidental. In fact, the head-down position resulted in diaphragm compression causing respiratory failure in combination with the stasis of the upper venous circle districts. Mechanical and gravitational forces related to upside-down position and increased vascular pressure also caused postmortem otorrhagia. In this case, the death scene investigation and circumstantial information allowed for reconstruction of the unique dynamics of the death. At the death scene, the position of the corpse must be accurately investigated because it can explain some cadaveric findings such as the ear bleeding or other markers of increased cephalic venous pressure like pink teeth, facial and conjunctival petechiae, or Tardieu spots. Therefore, forensic pathologists should consider that ear bleeding in dead bodies is not always the evidence of severe head blunt trauma or diving accidents, but it might be a postmortem phenomenon mostly related to body position.

The effects of a recruitment manoeuvre (RM) with positive end-expiratory pressure (PEEP) on lung compliance (C LUNG ) are not well characterised in robot-assisted laparoscopic radical prostatectomy (RARP). Patients were allocated to group R (n = 10; with an RM) or C (n = 9; without an RM). An RM involved sustained inflation of 30 cmH 2 O for 30 s. The lungs were ventilated with volume-controlled ventilation with tidal volume of 7 mL kg -1 of predicted body weight and fraction of inspired oxygen of 0.5. End-tidal carbon dioxide pressure was maintained at normocapnia. Patients were in the horizontal lithotomy position (pre-op). After pneumoperitoneum, patients underwent RARP in a steep Trendelenburg lithotomy position at a PEEP level of 0 cmH 2 O (RARP0). An RM was used in the R group but not in the C group. Patients were then ventilated with 5 cmH 2 O PEEP for 1 h after RARP0 (RARP5.1) and 2 h after RARP0 (RARP5.2). Oesophageal pressure and airway pressure were measured for calculating C LUNG and chest wall compliance. C LUNG significantly decreased from pre-op to RARP0 and did not significantly increase from RARP0 to RARP5.1 and RARP5.2 in either group. C LUNG differed significantly between groups at RARP5.1 and RARP5.2 (103 ± 30 vs. 68 ± 11 mL cm -1 H 2 O and 106 ± 35 vs. 72 ± 9 mL cm -1 H 2 O; P < 0.05). In patients undergoing RARP, with the addition of RM, the C LUNG was effectively increased from the horizontal lithotomy position to the steep Trendelenburg lithotomy position under pneumoperitoneum.

Background: Optic nerve sheath diameter (ONSD) measurement with ultrasound has emerged as a simple, non-invasive and reliable surrogate of invasive intracranial pressure (ICP) measurement. Increase in ICP might lead to postoperative nausea and vomiting (PONV) and postoperative headache. Here, we aimed to evaluate the extent of change in ONSD, resulting from pneumoperitoneum (PP) and Trendelenburg (TP) position during the laparoscopic hysterectomy (LH), by using ultrasonographic ONSD measurement. We also aimed to investigate the relation of ONSD with PONV and postoperative headache., Methods: Sixty-one patients undergoing LH with general anesthesia were enrolled in this prospective study. ONSD was measured at six time-points during the LH. The primary outcome of the study was the change in ONSD with the introduction of PP and TP. The relation of ONSD with PONV and postoperative headache were the secondary outcomes., Results: ONSD demonstrated an increasing trend from baseline to the 10th minute of the TP. A relative decrease occurred in ONSD following supine positioning which further decreased after the release of the PP. However, even after the release of the PP, the median ONSD was significantly higher compared to the baseline values (5.1 mm vs. 4.9 mm, P<0.01). Presence of PONV and headache were significantly correlated with the extent of the increase in ONSD from baseline to PP and from baseline to TP. ROC curve analysis revealed that a cut-off value of 5.85 mm for ONSD was predictive for PONV (P<0.001)., Conclusions: Combination of PP and TP leads to a significant increase in ONSD during LH. The extent of the increase in ONSD during the procedure is significantly correlated with PONV and headache occurring within the first three hours of recovery.

Background: Robot-assisted laparoscopic radical prostatectomy (RLRP) can increase intracranial pressure (ICP) related to a change in position. Increasing ICP may result in various ocular complications, which are rare but serious, such as a corneal abrasion and ischemic optic neuropathy. We performed a prospective observational trial using ultrasonographic measurements to compare optic nerve sheath diameter (ONSD) related to ICP between patients who received either propofol or sevoflurane and underwent RLRP., Methods: Thirty-two male patients scheduled to undergo RLRP were assigned into groups according to the anesthetic agent used (group P: propofol, n  = 16; group S: sevoflurane, n  = 16). ONSD, end-tidal partial pressure of CO 2 , and blood pressure were measured 10 min after induction of anesthesia (T0), 30 min (T1), 60 min (T2), and 90 min after changing to the steep Trendelenburg position and introducing a pneumoperitoneum (T3) and 10 min after returning the patient's position to supine (T4) during surgery., Results: No significant differences were observed in the demographic data of the patients, surgery time, or intraoperative variables, including hemodynamic and respiratory variables, at any of the time points. The mean right ONSDs in the propofol and sevoflurane groups were 37.3 and 40.1 mm at 30 min ( p =0.003), respectively. The mean left ONSDs were 38.4 and 40.8 mm at 30 min ( p =0.021) after changing to the Trendelenburg position. The ONSDs between the two groups were significantly different during surgery., Conclusions: ONSD increased more in the sevoflurane group than in the propofol group during RLRP. Intravenous anesthetics could alleviate the increase in ICP during RLRP., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2019 Yanghyun Kim et al.)

Objective: To assess the effects of different durations of simulated microgravity exposure on ventricular repolarization (VR) in terms of T-wave alternans (TWA) as well as to test whether an increase in VR heterogeneity could be detected once normal gravity was restored., Approach: A total of 63 healthy volunteers were recruited in several head-down bed-rest (HDBR) experiments in the context of the European Space Agency bed-rest strategy. TWA is evaluated during the night period using ambulatory ECG recordings, before, during and after long- (60 d), mid- (21 d) and short- (5 d) duration HDBR by the long-term averaging technique., Main Results: 5-21 d of exposure to simulated microgravity by means of the HDBR model do not lead to a significant increase of cardiac electrical instability in healthy myocardial substrates up to the point of eliciting TWA on the surface ECG. However, TWA indices increased after long-term HDBR exposure, once normal gravity was re-established, indicative of incipient electrical instability on VR at the conclusion of 60 d of HDBR., Significance: The results of this work underline the importance of focusing future research on immediate effects after long-term microgravity exposure, both simulated by HDBR or from space mission scenarios, once partial gravity conditions are re-established. A deeper insight in the understanding of human body reactions in these scenarios results crucial in the design of future long-duration spaceflight missions, to mitigate any potential risk that can limit astronaut's performance.

Background: The appropriate level of positive end-expiratory pressure (PEEP) during intra-operative mechanical ventilation remains unclear., Objective: The aim of this study was to investigate the effects of different levels of PEEP with low tidal volume (low-VT) ventilation in a steep Trendelenburg position (30°) and pneumoperitoneum on oxygenation, respiratory mechanics and ventilation distribution using electrical impedance tomography., Design: A randomised controlled trial., Setting: Single university secondary care centre, conducted from January 2017 to December 2017., Patients: Forty female patients, aged 20 to 60 years, and of American Society of Anesthesiologists' (ASA) physical status 1 or 2, undergoing elective robotic gynaecological surgery were included., Intervention: Forty patients were allocated randomly to a PEEP4 (PEEP 4 cmH2O) group or a PEEP8 (PEEP 8 cmH2O) group., Main Outcome Measures: The primary outcomes were respiratory mechanics. The secondary outcomes included changes in ventilation distribution across the ventral and dorsal regions of interest and postoperative pulmonary complications (PPCs) using a modified clinical pulmonary infection score., Results: There was no difference in PaO2 at any time point. The peak inspiratory pressure (PIP) and mean airway pressure (MPAW) of the PEEP4 group were lower than those of the PEEP8 group (P < 0.001). The oxygenation factor in the PEEP4 group was higher than that in the PEEP8 group during mechanical ventilation at all times. There was no difference in the fractional distribution of end-expiratory ventilation according to region of interest between the two groups., Conclusion: Both 4 and 8 cmH2O of PEEP with low-VT ventilation can be used for robotic gynaecological surgery that requires a steep Trendelenburg position and pneumoperitoneum. However, 8 cmH2O of PEEP had no benefit over 4 cmH2O of PEEP with respect to oxygenation and improvement of dorsal regional ventilation., Trial Registration: The trial was registered at the Clinical Trial Registry of Korea (KCT0002255). https://cris.nih.go.kr.

Background: The use of traction during hip arthroscopy is commonly used to provide safe joint access and to improve visualization. However, traction during hip arthroscopy has been associated with complications ranging from transient neuropraxias to devastating soft-tissue necrosis. Trendelenburg positioning may be helpful, but the degree to which this is true is not well understood., Questions/purposes: To determine whether there would be a reduction in perineal pressure at 5°, 10°, and 15° of Trendelenburg compared with baseline (0° of Trendelenburg) while in the modified supine position during hip arthroscopy., Methods: A consecutive cohort of 50 patients treated with hip arthroscopy by a single, high-volume orthopaedic surgeon was analyzed. There were 30 females and 20 males in this study, with a mean age of 36 ± 16 years (range, 14 to 66 years); mean BMI was 26 kg/m. In the operating room, patients were placed in the modified supine position on a traction extension table with a well-padded perineal post. A standard blood pressure cuff was secured to the post to measure pressure exerted on the perineum as traction was applied to distract the hip. For each patient, pressure against the perineum was measured at four different positions using a digital level: 0°, 5°, 10°, and 15° of Trendelenburg. These positions were tested in a random order for each patient. Mean pressure was compared within patients under the four-period crossover design using a repeated-measure (mixed) ANOVA model. Examination of the residual error quantile plot showed that the pressure data followed a normal distribution, making the use of a parametric model appropriate. Tests were made for period and order effects., Results: Compared with baseline (0° or no Trendelenburg) there was a reduction in pressure of 4.4 (15.5%) at 5° of Trendelenburg (p = 0.203), 8 (28%) at 10° of Trendelenburg (p = 0.022) and 13.1 (46%) at 15° (p = 0.006). These results were maintained regardless of the sequence of positions used in each patient (0°, 5°, 10°, 15°)., Conclusions: Trendelenburg positioning of 10° and 15° during hip arthroscopy resulted in decreased perineal pressure compared with the neutral (0°) position. This technique is intended to harness gravity to exert the majority of countertraction while retaining the perineal post as a backup patient stabilizer. Routine introduction of Trendelenburg during hip arthroscopy reduces perineal pressure against the post, which may decrease complications related to traction and perineal pressure. Future studies should assess whether the observed differences in perineal pressure will reduce the frequency of post-related complications after hip arthroscopy., Level of Evidence: Level II, therapeutic study.

The aim of the study was to compare proteomic data on the effects of spaceflight factors on the human body, including both real space missions and ground-based experiments. LC-MS/MS-based proteomic analysis of blood plasma samples obtained from 13 cosmonauts before and after long-duration (169-199 days) missions on the International Space Station (ISS) and for five healthy men included in 21-day-long head-down bed rest (HDBR) and dry immersion experiments were performed. The semi-quantitative label-free analysis revealed significantly changed proteins: 19 proteins were significantly different on the first (+1) day after landing with respect to background levels; 44 proteins significantly changed during HDBR and 31 changed in the dry immersion experiment. Comparative analysis revealed nine common proteins ( A1BG, A2M, SERPINA1, SERPINA3, SERPING1, SERPINC1, HP, CFB, TF ), which changed their levels after landing, as well as in both ground-based experiments. Common processes, such as platelet degranulation, hemostasis, post-translational protein phosphorylation and processes of protein metabolism, indicate common pathogenesis in ground experiments and during spaceflight. Dissimilarity in the lists of significantly changed proteins could be explained by the differences in the dynamics of effective development in the ground-based experiments. Data are available via ProteomeXchange using the identifier PXD013305.

Introduction: Long-term head-down bed rest (HDBR) results in musculoskeletal losses similar to those observed during long-term space flight. Agents such as testosterone, in addition to regular exercise, are effective countermeasures for reducing loss of skeletal muscle mass and function., Objective: We investigated the skeletal muscle proteome of healthy men in response to long term HDBR alone (CON) and to HDBR with exercise (PEX) or exercise plus testosterone (TEX) countermeasures., Method: Biopsies were performed on the vastus lateralis before (pre) HDBR and on HDBR days 32 (mid) and 64 (post). Extracted proteins from these skeletal muscle biopsies were subjected to 2-dimensional gel electrophoresis (2DE), stained for phosphoproteins (Pro-Q Diamond dye) and total proteins (Sypro Ruby dye). Proteins showing significant fold differences (t-test p ≤ 0.05) in abundance or phosphorylation state at mid or post were identified by mass spectroscopy (MS)., Results: From a total of 932 protein spots, 130 spots were identified as potentially altered in terms of total protein or phosphoprotein levels due to HDBR and/or countermeasures, and 59 unique molecules emerged from MS analysis. Top canonical pathways identified through IPA included calcium signaling, actin cytoskeleton signaling, integrin linked kinase (ILK) signaling, and epithelial adherens junction signaling. Data from the pre-HDBR proteome supported the potential for predicting physiological post-HDBR responses such as the individual's potential for loss vs. maintenance of muscle mass and strength., Conclusions: HDBR resulted in alterations to skeletal muscle abundances and phosphorylation of several structural and metabolic proteins. Inclusion of exercise alone or in combination with testosterone treatment modulated the proteomic responses towards cellular reorganization and hypertrophy, respectively. Finally, the baseline proteome may aid in the development of personalized countermeasures to mitigate health risks in astronauts as related to loss of muscle mass and function., Competing Interests: The authors have declared that no competing interests exist.

Objectives: Critically ill patients in emergency departments (ED) frequently require catheterization of the internal jugular vein. For jugular insertion, the Trendelenburg position (TP) is recommended. However, many patients in the ED do not tolerate lying in the supine or even the head-down position, or TP is contraindicated for other reasons. The aim of our trial was to investigate to which extent TP is either not tolerated or contraindicated in the target population of patients admitted to the ED., Patients and Methods: This was a clinical observational trial, carried out in an ED of a Tertiary Healthcare Hospital, including critically ill patients. From October 2015 to January 2016, we enrolled 117 nonintubated patients over 18 years admitted to the ED of Jena University Hospital, a Tertiary Healthcare Facility. Patients were positioned in TP (15° head-down) for a maximum of 10 min. If the position had to be abandoned for any reason, time to abandonment and reason for ending the position were recorded. 38.5% of all enrolled patients could not be positioned in TP because of contraindications (17.9%) or intolerance of the positioning (20.5%)., Results and Conclusion: For central venous catheterization, TP remains the gold standard. Our trial shows the limitations of this positioning for critically ill patients. Almost 40% of the patients could not be tilted 15° head-down. Therefore, guideline recommendations should be reconsidered and alternatives should be sought.

Robotic surgeries in the extreme Trendelenburg position can lead to changes in the airway dimensions. We conducted a prospective, observational trial to explore the use of ultrasound to quantify these changes in the airway dimensions and identify the factors associated with it. Fifty-two American society of Anaesthesiologists physical status I-II patients between 18 and 70 years of age of either sex scheduled to undergo robot assisted urological procedures in steep Trendelenburg position were enrolled. Anterior soft tissue thickness at the level of hyoid bone and vocal cords, tongue thickness, Malampatti grading and neck circumference were measured at predefined postoperative intervals in the immediate postoperative period, at 2-, 6- and 12-h period postoperatively. Linear stepwise regression analysis was done to explore the factors associated with change in anterior tissue thickness immediately after surgery. The mean difference (95%; CI) in the anterior soft tissue thickness in the immediate postoperative period at the level of hyoid was 0.023 (0.029-0.016) cm, p < 0.001 and at level of vocal cords was - 0.012 (- 0.017 to - 0.008) cm, p < 0.001 from the baseline. There was a significant increase in tongue thickness (0.002), Mallampati score (p = 0.002) and neck circumference (p < 0.001) in immediate postoperative period. The change in anterior tissue thickness at the level of hyoid was affected by total intraoperative fluids used (r = 0.602, p < 0.001), airway trauma (r = 0.275, p = 0.002) and duration of surgery (r = 0.243, p = 0.025). Significant changes in airway dimensions after robotic surgeries in Trendelenburg position persist till 2 h in the postoperative period which warrant vigilant monitoring for any airway compromise during this period.

Background: We evaluated the relationship between ultrasonographical acquired parameters and short-term postoperative cognitive function in patients undergoing robotic-assisted radical prostatectomy (RALP)., Methods: Ninety elderly patients scheduled for RALP had their optic nerve sheath diameter (ONSD), the cross-sectional area (CSA) of the internal jugular vein (IJV) and the IJV valve (IJVV) competency assessed by ultrasound. The patients were analyzed in 2 groups based on whether displayed IJVV incompetency (IJVVI). The 3 parameters were measured before anesthesia (T0), immediately after induction of general anesthesia (T1), 5 minutes after establishing pneumoperitoneum (T2), 5 minutes after placing the patient in the Trendelenburg position (T3), and 5 minutes after the release of the pneumoperitoneum in the supine position (T4). Regional cerebral tissue oxygen saturation (rSO2) was also measured by near-infrared spectroscopy intraoperatively. The Mini-Mental State Examination (MMSE) and Confusion Assessment Method (CAM) were performed the day before surgery and on postoperative days 1, 3, and 7., Results: We found that 52% of patients had evidence of IJVVI after being placed in the Trendelenburg position after pneumoperitoneum was established (T4). Patient with IJVVI showed a significant increase of ONSD and CSA at T1, T2, T3, T4 but there was no associated decrease in rSO2. MMSE scores were reduced at postoperative day 1 and the 7 patients that developed postoperative delirium came from Group IJVVI., Conclusions: Our observations suggest that elderly patients that show IJVVI after adequate positioning for RALP may develop elevated intracranial pressure as well as mildly compromised postoperative cognitive function in the short term.

Robot-assisted surgery can cause raised intracranial pressures (ICP) due to steep trendelenburg position and pneumoperitoneum. The choice of anesthetic agents can influence the ICP, which can be measured indirectly by correlating it with the sonographically measured optic nerve sheath diameter (ONSD). In this study, our primary aim was to compare the change from baseline of the ONSD during propofol versus sevoflurane-maintained anesthesia in patients undergoing robotic pelvic surgery. In this prospective, interventional, double-blinded study, we randomised 50 patients into two groups P and S. Subjects in group P received intravenous propofol infusion while those in group S received inhalation sevoflurane for maintenance of anesthesia. The ONSD at fixed intervals was noted as the mean of four values measured using ultrasound in both eyes by two independent anesthesiologists who were blinded to the group allocation. The patient demographics and baseline parameters were similar. The mean maximum rise in ONSD from baseline was 0.01 ± 0.01 cm in group P while it was 0.03 ± 0.01 cm in group S (p = 0.001). Percentage change from baseline in group P was 3.41 ± 1.81% and 8.00 ± 2.95% in group S (p = 0.001). We found a positive correlation between the duration of surgery and the maximum rise in ONSD in group S (p = 0.003), but not in group P. Propofol-based total intravenous anesthesia is more effective than inhalation sevoflurane in attenuating the increase in ICP as correlated with the ONSD during robotic pelvic surgery.Clinical trial registration: Yes; Principal investigator: Nambiath Sujata; Trial number: REF/2016/11/012713 (registered); Trial registry: CTRI- http://ctri.nic.in .

Laparoscopic surgery is often prolonged and requires positional changes to facilitate surgical access. Previous studies reported intraocular pressure (IOP) changes in one fixed position. This study investigated the effect of desflurane and propofol anesthesia on IOP during repeated positional changes. A total of 46 patients undergoing laparoscopic colorectal surgery were randomized into desflurane or propofol groups. IOP was measured using a handheld tonometer at seven time points: before induction (baseline), after endotracheal intubation, after pneumoperitoneum, after the first Trendelenburg and right tilt position, after reverse Trendelenburg and right tilt position, after the second Trendelenburg and right tilt position and before endotracheal extubation. Trendelenburg positioning raised IOP in both groups. In the desflurane group, IOP at the first Trendelenburg position was 6.27 and 8.48 mmHg higher than baseline IOP in left and right eye, respectively; IOP at the second Trendelenburg position was 7 and 9.44 mmHg higher than baseline in left and right eye, respectively. In the propofol group, IOP at the first Trendelenburg position was 2.04 and 4.04 mmHg higher than baseline in left and right eyes, respectively. It was 3.04 and 4.87 mmHg higher than baseline in left and right eye, respectively, at the second Trendelenburg position. In the desflurane group, 56.52% patients exhibited high IOP (≥ 25 mmHg) compared with 13.04% in the propofol group at the second Trendelenburg position in the right eyes (P = 0.005). There was a positive correlation between IOP and peak inspiratory pressure (P < 0.001). Propofol anesthesia mitigated wide variations in IOP caused by repetitive positional changes during laparoscopic colorectal surgery.

Background: Mechanisms of peri-operative ischaemic optic neuropathy remain poorly understood. Both specific pre-operative and intra-operative factors have been examined by retrospective studies, but no animal model currently exists., Objectives: To develop a rodent model of peri-operative ischaemic optic neuropathy. In rats, we performed head-down tilt and/or haemodilution, theorising that the combination damages the optic nerve., Design: Animal study., Setting: Laboratory., Animals: A total of 36 rats, in four groups, completed the functional examination of retina and optic nerve after the interventions., Interventions: Anaesthetised groups (n>8) were supine (SUP) for 5 h, head-down tilted 70° for 5 h, head-down tilted/haemodiluted for 5 h or SUP/haemodiluted for 5 h. We measured blood pressure, heart rate, intra-ocular pressure and maintained constant temperature., Main Outcome Measurements: Retinal function (electroretinography), scotopic threshold response (STR) (for retinal ganglion cells) and visual evoked potentials (VEP) (for transmission through the optic nerve). We imaged the optic nerve in vivo and evaluated retinal histology, apoptotic cells and glial activation in the optic nerve. Retinal and optic nerve function were followed to 14 and 28 days after experiments., Results: At 28 days in head down tilted/haemodiluted rats, negative STR decreased (about 50% amplitude reduction, P = 0.006), VEP wave N2-P3 decreased (70% amplitude reduction, P = 0.01) and P2 latency increased (35%, P = 0.003), optic discs were swollen and glial activation was present in the optic nerve. SUP/haemodiluted rats had decreases in negative STR and increased VEP latency, but no glial activation., Conclusion: An injury partly resembling human ischaemic optic neuropathy can be produced in rats by combining haemodilution and head-down tilt. Significant functional changes were also present with haemodilution alone. Future studies with this partial optic nerve injury may enable understanding of mechanisms of peri-operative ischaemic optic neuropathy and could help discover preventive or treatment strategies.

Study Objective: To study the effects of intraoperative dexmedetomidine on the intraocular pressure (IOP) in patients undergoing robot-assisted laparoscopic radical prostatectomy (RALRP) under propofol-remifentanil anesthesia., Design: Double-blind, randomized controlled trial., Setting: Operating room., Patients: Forty consenting male patients aged ≥20 to <80 years with American Society of Anesthesiologists physical status classes I and II., Interventions: The patients were randomly assigned to either dexmedetomidine (DEX) (n = 20) or control (n = 20) group. Anesthesia was induced and maintained using propofol, remifentanil, and rocuronium. In the dexmedetomidine group, dexmedetomidine was administered at 0.4 μg/kg/h immediately after anesthesia induction until the end of the surgery, whereas normal saline was administered as placebo in the control group., Measurements: IOP was measured using a rebound tonometer. Time points of measuring IOP were as follows: T1: before anesthesia induction, T2: 5 min after intubation, T3: 60 min after placing patient in the Trendelenburg position, T4: 120 min after placing patient in the Trendelenburg position, T5: 180 min after placing patient in the Trendelenburg position, T6: 5 min after placing patient in a horizontal position, T7: 5 min after extubation, and T8: 30 min after extubation., Main Results: A linear mixed model analysis demonstrated a significant intergroup difference in IOP over time and during pneumoperitoneum in the steep Trendelenburg position. IOP at T5 was significantly lower in the dexmedetomidine group than in the control group even after post-hoc analysis in the steep Trendelenburg position periods with Bonferroni correction., Conclusions: Dexmedetomidine combined with propofol decreases IOP in the steep Trendelenburg position during RALRP., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Steep Trendelenburg during surgery has been associated with many position-related injuries. The American Society of Anesthesiology practice advisory recommends documentation, frequent position checks, avoiding shoulder braces, and limiting abduction of upper extremities to avoid brachial plexopathy. We conducted a web-based survey to assess anesthesiologists' practices, institutional policies, and complications encountered when using steep Trendelenburg., Methods: Two thousand fifty randomly selected active members of the American Society of Anesthesiology were invited via email to participate in a 9-item web-based survey. Results are reported as absolute numbers and proportions with 95% confidence interval (CI)., Results: Survey response rate was 290 of 2050 (14.1%). 44.6% (95% CI, 38.9-50.3) of the respondents documented anesthesia start and finish, 73.9% (95% CI, 68.8-79) frequently checked positioning during surgery, 30.8% (95% CI, 25.4-36.2) reported using shoulder braces, 66.9% (95% CI, 61.5-72.3) tucked patients' arms to the side, 54.0% (95% CI, 48.2-59.8) limited fluid administration, and more than two-thirds did not limit the duration or inclination angle. Notably, 63/290 (21.7%) reported a complication and only 6/289 (2.1%) had an institutional policy. The most common complication was airway and face edema, second was brachial plexus injury, and third was corneal abrasions. Most institutional policies, when present, focused on limiting duration of steep Trendelenburg and communication with surgical team. Only 1/6 policies required avoiding use of shoulder braces., Conclusion: Based on survey results, practices related to steep Trendelenburg varied among USA anesthesiologists. Differences included protective measures, documentation, positioning techniques, fluid management, and institutional guidelines. The singular commonality found among all respondents was lack of institutional policies. Survey results highlighted the need for institutional policies and more education.

Purpose of Review: Laparoscopy is routinely performed for the treatment and management of gynaecologic disorders. During gynaecologic laparoscopy, the patient is placed in the Trendelenburg position to optimize visualization and access to the pelvis. The Trendelenburg position may result in complications in many organ systems., Recent Findings: Trendelenburg positioning may cause rare, potentially life-threatening complications of the respiratory and cardiovascular systems. Case reports of visual field loss and cognitive aberrations following Trendelenburg positioning have been published. Few intervention studies have been performed evaluating attenuation of changes in intraocular pressure and haemodynamics., Summary: This review summarizes possible complications related to the Trendelenburg position and current evidence regarding interventions to minimize the risk of complications.

Objective: After severe (primary) brain injury, Dutch physician-based helicopter emergency medical services start therapy to lower the intracranial pressure (ICP) on scene to stop or delay secondary brain injury. In some cases, helicopter transportation to the nearest level 1 trauma center is indicated. During transportation, the head-down position may counteract the ICP-lowering strategies because of venous blood pooling in the head. To examine this theory, we measured the optic nerve sheath diameter (ONSD) during helicopter transport in healthy volunteers., Methods: The ONSD was measured by ultrasound in healthy volunteers during helicopter liftoff and acceleration in the supine position or with a raised headrest., Results: In this proof-of-principle study, the ONSD increased during helicopter acceleration (-9° Trendelenburg, mean = 5.6 ± .3 mm) from baseline (0° supine position, mean = 5.0 ± .4 mm). After headrest elevation (20°-25°), the ONSD did not increase during helicopter acceleration (mean ONSD = 5.0 ± .5 mm)., Conclusion: ONSD and ICP seem to increase during helicopter transportation in -9° head-down (Trendelenburg) position. By raising the headrest of the gurney before liftoff, these effects can be prevented., (Copyright © 2018 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.)

Robotic surgical platforms are now in widespread use in the practice of gynecology all over the world. The introduction of robotic surgery has required some modifications of patient positioning when compared to standard laparoscopic surgery. Optimal patient positioning is likely to be the most essential step of robotic surgery as it provides the technical feasibility to have adequate access to the pelvic structures for performing the surgery. It is prudent to pay attention to preventing patient shifting in Trendelenburg position because of tendency of sliding down toward the direction of the head. Inappropriate patient positioning is associated with inadequate exposure of the operative field as well as detrimental complications that may lead to long-term side effects. These issues can be reduced with use of proper or strategic positioning technique. The purpose of this review is to highlight important points to properly position patient for robot-assisted laparoscopic benign gynecologic surgery and protect patient from position-related injuries., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Microgravity and elevated levels of CO 2 are two common environmental stressors in spaceflight that may affect cognitive performance of astronauts. In this randomized, double-blind, crossover trial (SPACECOT), 6 healthy males (mean ± SD age: 41 ± 5 yr) were exposed to 0.04% (ambient air) and 0.5% CO 2 concentrations during 26.5-h periods of -12° head-down tilt (HDT) bed rest with a 1-wk washout period between exposures. Subjects performed the 10 tests of the Cognition Test Battery before and on average 0.1, 5.2, and 21.0 h after the initiation of HDT bed rest. HDT in ambient air induced a change in response strategy, with increased response speed (+0.19 SD; P = 0.0254) at the expense of accuracy (-0.19 SD; P = 0.2867), resulting in comparable cognitive efficiency. The observed effects were small and statistically significant for cognitive speed only. However, even small declines in accuracy can potentially cause errors during mission-critical tasks in spaceflight. Unexpectedly, exposure to 0.5% CO 2 reversed the response strategy changes observed under HDT in ambient air. This was possibly related to hypercapnia-induced cerebrovascular reactivity that favors cortical regions in general and the frontal cortex in particular, or to the CNS arousing properties of mildly to moderately increased CO 2 levels. There were no statistically significant time-in-CO 2 effects for any cognitive outcome. The small sample size and the small effect sizes are major limitations of this study and its findings. The results should not be generalized beyond the group of investigated subjects until they are confirmed by adequately powered follow-up studies. NEW & NOTEWORTHY Simulating microgravity with exposure to 21 h of -12° head-down tilt bed rest caused a change in response strategy on a range of cognitive tests, with a statistically significant increase in response speed at the expense of accuracy. Cognitive efficiency was not affected. The observed speed-accuracy tradeoff was small but may nevertheless be important for mission-critical tasks in spaceflight. Importantly, the change in response strategy was reversed by increasing CO 2 concentrations to 0.5%.

To understand the impact of physical deconditioning with head-down tilt bed rest (HDBR) on the malleability of sympathetic discharge patterns, we studied 1) baseline integrated muscle sympathetic nerve activity (MSNA; microneurography) from 13 female participants in the WISE-2005 60-day HDBR study (retrospective analysis), 2) integrated MSNA and multiunit action potential (AP) analysis in 13 male participants performed on data collected at baseline and during physiological stress imposed by end-inspiratory apnea in a new 60-day HDBR study, and 3) a repeatability study (control; n = 6, retrospective analysis, 4 wk between tests). Neither baseline integrated burst frequency nor incidence were altered with HDBR (both P > 0.35). However, baseline integrated burst latency increased in both HDBR studies (male: 1.35 ± 0.02 to 1.39 ± 0.02 s, P < 0.01; female: 1.23 ± 0.02 to 1.29 ± 0.02 s, P < 0.01), whereas controls exhibited no change across two visits (1.25 ± 0.02 to 1.25 ± 0.02 s, group-by-time interaction, P = 0.02). With the exception of increased AP latency ( P = 0.03), male baseline AP data did not change with HDBR (all P > 0.19). The change in AP frequency on going from baseline to apnea (∆94 ± 25 to ∆317 ± 55 AP/min, P < 0.01) and the number of active sympathetic clusters per burst (∆0 ± 0.2 to ∆1 ± 0.2 clusters/burst, P = 0.02) were greater post- compared with pre-HDBR. The change in total clusters with apnea was ∆0 ± 0.5 clusters pre- and ∆2 ± 0.7 clusters post-HDBR ( P = 0.07). These data indicate that 60-day HDBR modified discharge characteristics in baseline burst latency and sympathetic neural recruitment during apneic stress. NEW & NOTEWORTHY Long-duration bed rest did not modify baseline sympathetic burst frequency in male and female participants, but examination of additional features of the multiunit signal provided novel evidence to suggest augmented synaptic delays or processing times at baseline for all sympathetic action potentials. Furthermore, long-duration bed rest increased reflex-sympathetic arousal to apneic stress in male participants primarily by mechanisms involving an augmented firing rate of action potential clusters active at baseline.

Risk of optic nerve injury after prolonged Trendelenburg's position Postoperative loss of vision due to acute ischaemic optic nerve injury is a rare complication following pelvic surgery. A steep Trendelenburg's position of the patient, high intraabdominal pressure and a long operative time in Trendelenburg's position are recognised risk factors associated with robot-assisted pelvic surgery. This manuscript presents the underlying pathophysiologic mechanism. Practical tips and tricks for prevention are discussed.

Study Objective: The aim of this study was to investigate how steep Trendelenburg positioning with pneumoperitoneum modifies brain oxygenation and autonomic nervous system modulation of heart rate variability during robotic sacrocolpopexy., Design: Prospective study (Canadian Task Force classification III)., Setting: Rambam Health Care Campus., Patients: Eighteen women who underwent robotic sacrocolpopexy for treatment of uterovaginal or vaginal apical prolapse., Interventions: Robotic sacrocolpopexy., Measurements and Main Results: A 5-minute computerized electrocardiogram, cerebral O 2 saturation (cSO 2 ), systemic O 2 saturation, heart rate (HR), diastolic blood pressure (BP), systolic BP, and end-tidal CO 2 tension were recorded immediately after anesthesia induction (baseline phase) and after alterations in positioning and in intra-abdominal pressure. HR variability was assessed in time and frequency domains. Cerebral oxygenation was measured by the technology of near-infrared spectrometry. cSO 2 at baseline was 73% ± 9%, with minor and insignificant elevation during the operation. Mean HR decreased significantly when the steep Trendelenburg position was implemented (66 ± 10 vs 55 ± 9 bpm, p < .05) and returned gradually to baseline with advancement of the operation and the decrease in intra-abdominal pressure. Concomitant with this decrease, the power of both arms of the autonomic nervous system increased significantly (2.8 ± .8 vs 3.3 ± .9 ms 2 /Hz and 2.5 ± 1.2 vs 3.2 ± .9 ms 2 /Hz, respectively, p < .05). All these effects occurred without any significant shifts in systolic or diastolic BP or in systemic or cerebral oxygenation., Conclusion: This study supports the safety of robotic sacrocolpopexy performed with steep Trendelenburg positioning with pneumoperitoneum. Only minor alterations were observed in cerebral oxygenation and autonomic perturbations, which did not cause clinically significant alterations in HR rate and HR variability., (Copyright © 2017 American Association of Gynecologic Laparoscopists. Published by Elsevier Inc. All rights reserved.)