BACKGROUND: During gynecological laparoscopic surgery, pneumoperitoneum and the Trendelenburg position (TP) can lead to increased intracranial pressure (ICP). However, it remains unclear whether perioperative fluid therapy impacts ICP. The purpose of this research was to evaluate the impact of restrictive fluid (RF) therapy versus conventional fluid (CF) therapy on ICP in gynecological laparoscopic surgery patients by measuring the ratio of the optic nerve sheath diameter (ONSD) to the eyeball transverse diameter (ETD) using ultrasound.
METHODS: Sixty-four patients who were scheduled for laparoscopic gynecological surgery were randomly assigned to the CF group or the RF group. The main outcomes were differences in the ONSD/ETD ratios between the groups at predetermined time points. The secondary outcomes were intraoperative circulatory parameters (including mean arterial pressure, heart rate, and urine volume changes) and postoperative recovery indicators (including extubation time, length of post-anaesthesia care unit stay, postoperative complications, and length of hospital stay).
RESULTS: There were no statistically significant differences in the ONSD/ETD ratio and the ONSD over time between the two groups (all p > 0.05). From T2 to T4, the ONSD/ETD ratio and the ONSD in both groups were higher than T1 (all p < 0.001). From T1 to T2, the ONSD/ETD ratio in both groups increased by 14.3%. However, the extubation time in the RF group was shorter than in the CF group [median difference (95% CI) -11(-21 to -2) min, p = 0.027]. There were no differences in the other secondary outcomes.
CONCLUSIONS: In patients undergoing laparoscopic gynecological surgery, RF did not significantly lower the ONSD/ETD ratio but did shorten the tracheal extubation time, when compared to CF.
BACKGROUND: ChiCTR2300079284. Registered on December 29, 2023.

It is a consensus in the international manned space field that factors such as microgravity during the space flight can cause anxiety, depression and other important brain function abnormalities in astronauts. However, the neural mechanism at the molecular level is still unclear. Due to the limitations of research conditions, studies of biological changes in the primate brain have been comparatively few. We took advantage of -6° head-down bed rest (HDBR), one of the most implemented space analogues on the ground, to investigate the effects of simulated weightlessness on non-human primate brain metabolites. The Rhesus Macaque monkeys in the experiment were divided into three groups: the control group, the 42-day simulated weightlessness group with HDBR, and the recovery group, which had 28 days of free activity in the home cage after the HDBR. Liquid chromatography-mass spectrometry (LC-MS) was used to perform metabolomics analysis on specific brain areas of the monkeys under three experimental conditions. Our results show that simulated weightlessness can cause neurotransmitter imbalances, the amino acid and energy metabolism disorders, and hormone disturbances. But these metabolomics changes are reversible after recovery. Our study suggests that long-term brain damage in space flight might be reversible at the metabolic level. This lays a technical foundation for ensuring brain health and enhancing the brain function in future space studies.

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.

UNASSIGNED: Head-down training can affect behavioural and neurocognitive control while performing dual tasks (DT). Breathing training improves motor and cognitive performance in patients with chronic obstructive pulmonary disease (COPD). As a neurorehabilitation tool, functional near-infrared spectroscopy (fNIRS) has been demonstrated to be an effective method for detecting changes in brain activation during motor recovery, as well as monitoring patients\' long-term progress during DT in motor and cognitive performance. However, no studies have examined the combined effect of head-down position and breathing exercises on motor and cognitive performance during DT. This study will employ a novel intervention involving head-down strong abdominal breathing training to investigate its effects on motor and cognitive performance during DT in patients with COPD aiming to inform future training modalities in the community and at home.
UNASSIGNED: We will recruit participants from Anqing, China, through community announcements, bulletin board postings, WeChat, and offline visits and screen 72 patients with stable COPD, classified as Global Initiative for Chronic Obstructive Lung Disease (GOLD) I-II, by pulmonologists at the university hospital. All participants will be randomly assigned to the head-down strong abdominal breathing (tilt angle 0-30° on the inversion apparatus, respiratory rate 20-30 breaths/min), head-down training, and strong abdominal breathing training groups in a 1:1:1 ratio. The intervention will last 12 weeks, with sessions performed thrice weekly for 1 h.
UNASSIGNED: The primary outcomes will be motor-cognitive DT time, dual-task effects, correct responses to cognitive tasks, and gait characteristics assessed at baseline, 6 and 12 weeks of intervention. The patient\'s dorsolateral prefrontal cortex (PFC) will also be stimulated with fNIRS at wavelengths of 730 and 850 nm, with a sampling rate of 11 Hz, to record oxy-haemoglobin (oxy-Hb), deoxy-haemoglobin (deoxy-Hb), and total oxyhaemoglobin (total-Hb). Secondary outcomes will include pre- and post-intervention scales for dyspnoea, overall cognitive function, balance, and anxiety and depression.
UNASSIGNED: Alterations in the PFC involved in attentional control, planning, and decision-making may partially explain cognitive and motor deficits (such as impaired balance and slower walking speed) in patients with COPD. This study may help to understand the effects of head-down strong abdominal breathing training on cognitive and motor performance under DT in patients with COPD and compare it with head-down training and breathing training alone. It may also help to determine whether it is a simple and effective form of exercise at home and in the community.

Long-duration spaceflight (LDSF) is associated with unique hazards and linked with numerous human health risks including Spaceflight Associated Neuro-ocular Syndrome (SANS). The proposed mechanisms for SANS include microgravity induced cephalad fluid shift and increased Intracranial Pressure (ICP). SANS is a disorder seen only after LDSF and has no direct terrestrial pathologic counterpart as the zero G environment cannot be completely replicated on Earth. Head-down tilt, bed rest studies however have been used as a terrestrial analog and produce the cephalad fluid shift. Some proposed countermeasures for SANS include vasoconstrictive thigh cuffs and lower body negative pressure. Another potential researched countermeasure is the impedance threshold device (ITD) which can reduce ICP. We review the mechanisms of the ITD and its potential use as a countermeasure for SANS.

UNASSIGNED: In-office use of the Trendelenburg position has been shown to be a beneficial clinical tool to help decipher if a CSF pressure/volume component is part of the underlying etiologic process for a patient\'s persistent headache. Utilizing the Trendelenburg position at home could potentially be an additional diagnostic tool for the treating headache physician.
UNASSIGNED: Our headache practice has been using at-home self-Trendelenburg for the past 2 years and will present the clinical scenarios in which it seems to be the most helpful utilizing a case series of patients. These include (1) in those who just had a lumbar puncture and call for worsening headaches and do not have an obvious orthostatic component; (2) in those who had a spinal epidural blood patch for a presumed CSF leak and state there was no improvement; (3) in those who are on daily preventive CSF volume-lowering medications and call in with worsening headaches; (4) in those with known CSF pressure-dependent headaches high or low but who are not on daily preventive CSF volume modulatory medications; (5) in those with a history of migraine or other primary headache disorder to see if a new type of headache is possibly from a CSF leak or an abnormal reset of CSF pressure to an elevated state; (6) in those with triggered only headaches like cough or exertional headache.
UNASSIGNED: Utilizing at-home self-Trendelenburg can provide valuable information for the treating headache physician on possible underlying headache etiology and can guide specific treatment strategies. Its simplicity and quick declaration of results are very patient pleasing.

BACKGROUND: During laparoscopic surgery, pneumoperitoneum and Trendelenburg positioning applied to provide better surgical vision can cause many physiological changes as well as an increase in intracranial pressure. However, it has been reported that cerebral autoregulation prevents cerebral edema by regulating this pressure increase. This study aimed to investigate whether the duration of the Trendelenburg position had an effect on the increase in intracranial pressure using ultrasonographic optic nerve sheath diameter (ONSD) measurements.
METHODS: The near infrared spectrometry monitoring of patients undergoing laparoscopic hysterectomy was performed while awake (T0); at the fifth minute after intubation (T1); at the 30th minute (T2), 60th minute (T3), 75th minute (T4), and 90th minute (T5) after placement in the Trendelenburg position; and at the fifth minute after placement in the neutral position (T6).
RESULTS: The study included 25 patients. The measured ONSD values were as follows: T0 right/left, 4.18±0.32/4.18±0.33; T1, 4.75±0.26/4.75±0.25; T2, 5.08±0.19/5.08±0.19; T3, 5.26±0.15/5.26±0.15; T4, 5.36±0.11/5.37±0.12; T5, 5.45±0.09/5.48±0.11; and T6, 4.9±0.24/4.89±0.22 ( p < 0.05 compared with T0). ). No statistical difference was detected in all measurements in terms of MAP, HR and ETCO2 values compared to the T0 value (p > 0.05).
CONCLUSIONS: It was determined that as the Trendelenburg position duration increased, the ONSD values ​​increased. This suggests that as the duration of Trendelenburg positioning and pneumoperitoneum increases, the sustainability of the mechanisms that balance the increase in intracranial pressure becomes insufficient.
BACKGROUND: This study was registered at Clinical Trials.gov on 21/09/2023 (registration number NCT06048900).

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.

BACKGROUND: Ureteroscopy lithotripsy (URSL) presents a therapeutic option for patients with proximal ureteral calculi warranting active removal. This systematic review and meta-analysis aimed to assess the efficacy of the reverse Trendelenburg (RT) position during this procedure.
METHODS: A comprehensive literature search was conducted across PubMed, Embase, and Cochrane databases to identify randomized controlled trials and observational studies comparing RT versus standard positioning (STD) in patients undergoing URSL for proximal ureteral stones. Heterogeneity was measured with the Cochran\'s Q test, I2 statistics, and prediction intervals (PI). A DerSimonian and Laird random-effects model was utilized for all outcomes.
RESULTS: Four studies encompassing 505 patients undergoing URSL were analyzed. Among the studied participants, 293 (58%) underwent RT positioning. Overall, RT was associated with a lower average incidence of stone retropulsion (RR 0.42; 95% CI 0.27-0.65; I2=48%; PI 0.08-2.10) and a higher mean stone-free rate (RR 1.33; 95% CI 1.18-1.49; I2=0%). However, no significant difference between groups was found in the mean rate of overall complications (RR 0.76; 95% CI 0.40-1.43; I2=51%; PI 0.00-520.22) and operative time (MD -0.65; 95% CI -9.58-8.27; I2=94%; PI -111.95-110.65). In those with proximal ureteral stones undergoing RT positioning at only the 20° angle, there was a reduction in stone retropulsion without any measured heterogeneity (RR 0.35; 95% CI 0.23-0.52; I2=0%).
CONCLUSIONS: These findings suggest that RT positioning is effective in improving outcomes for patients with proximal ureteral stones undergoing URSL, and its use should be considered during the procedure.

BACKGROUND: The distribution and elimination of infused crystalloid fluid is known to be affected by general anesthesia, but it is unclear whether changes differ depending on whether the patient is operated in the flat recumbent position, the Trendelenburg (\"legs up\") position, or the reverse Trendelenburg (\"head up\") position.
METHODS: Retrospective data on hemodilution and urine output obtained during and after infusion of 1-2 L of Ringer\'s solution over 30-60 min were collected from 61 patients undergoing surgery under general anesthesia and 106 volunteers matched with respect to the infusion volume and infusion time. Parameters describing fluid distribution in the anesthetized and awake subjects were compared by population volume kinetic analysis.
RESULTS: General anesthesia decreased the rate constant for urine output by 79% (flat recumbent), 91% (legs up) and 91% (head up), suggesting that laparoscopic surgery per se intensified the already strong anesthesia-induced fluid retention. General anesthesia also decreased the rate constant governing the return of the distributed fluid to the plasma by 32%, 15%, and 70%, respectively. These results agree with laboratory data showing a depressive effect of anesthetic drugs on lymphatic pumping, and further suggest that the \"legs up\" position facilitates lymphatic flow, whereas the \"head up\" position slows this flow. Both Trendelenburg positions increased swelling of the \"third fluid space\".
CONCLUSIONS: General anesthesia caused retention of infused fluid with preferential distribution to the extravascular space. Both Trendelenburg positions had a modifying influence on the kinetic adaptations that agreed with the gravitational forces inflicted by tilting to body.