Association Between Acute Kidney Injury and the Trendelenburg Position Angle During Robot-assisted Radical Prostatectomy.

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.

The effects of robot-assisted laparoscopic surgery with Trendelenburg position on short-term postoperative respiratory diaphragmatic function.

OBJECTIVE: To study how Pneumoperitoneum under Trendelenburg position for robot-assisted laparoscopic surgery impact the perioperative respiratory parameters, diagrammatic function, etc. METHODS: Patients undergoing robot-assisted laparoscopic surgery in the Trendelenburg position and patients undergoing general surgery in the supine position were selected. The subjects were divided into two groups according to the type of surgery: robot-assisted surgery group and general surgery group. ① Respiratory parameters such as lung compliance, oxygenation index, and airway pressure were recorded at 5 min after intubation, 1 and 2 h after pneumoperitoneum. ② Diaphragm excursion (DE) and diaphragm thickening fraction (DTF) were recorded before entering the operating room (T1), immediately after extubation (T2), 10 min after extubation (T3), and upon leaving the postanesthesia care unit (T4). ③ Peripheral venous blood (5 ml) was collected before surgery and 30 min after extubation and was analyzed by enzyme-linked immunosorbent assay to determine the serum concentration of Clara cell secretory protein 16 (CC16) and surfactant protein D (SP-D). RESULT: ① Compared with the general surgery group (N = 42), the robot-assisted surgery group (N = 46) presented a significantly higher airway pressure and lower lung compliance during the surgery(P < 0.001). ② In the robot-assisted surgery group, the DE significantly decreased after surgery (P < 0.001), which persisted until patients were discharged from the PACU (P < 0.001), whereas the DTF only showed a transient decrease postoperatively (P < 0.001) and returned to its preoperative levels at discharge (P = 0.115). In the general surgery group, the DE showed a transient decrease after surgery(P = 0.011) which recovered to the preoperative levels at discharge (P = 1). No significant difference in the DTF was observed among T1, T2, T3, and T4. ③ Both the general and robot-assisted surgery reduced the postoperative serum levels of SP-D (P < 0.05), while the robot-assisted surgery increased the postoperative levels of CC16 (P < 0.001). CONCLUSION: Robot-assisted laparoscopic surgery significantly impairs postoperative diaphragm function, which does not recover to preoperative levels at PACU discharge. Elevated levels of serum CC16 after surgery suggest potential lung injury. The adverse effects may be attributed to the prolonged Trendelenburg position and pneumoperitoneum during laparoscopic surgery.

Retrograde Flow of Fluid Through the Nasolacrimal Duct System Under General Anesthesia: A Case Report.

This case report describes a rare incident of fluid exhibiting retrograde flow from the nasopharynx through the nasolacrimal duct and accumulating within the eye guard while under general anesthesia. The patient was in a steep Trendelenburg position for several hours and received multiple liters of intravenous fluid. The patient did not have a history of sinusitis, sinus surgery, cocaine use, dacryostenosis and dacryocystitis, or nasolacrimal duct irrigation and probing. This case provides insight into the potential ophthalmic implications of surgical and anesthetic management. While the patient fortunately had no complications, this case also underscores the importance of intraoperative vigilance.

Mesial temporal atrophy in preoperative MRI rather than steep Trendelenburg position is associated with postoperative delirium in patients undergoing a major urologic surgery.

PURPOSE: To investigate whether steep Trendelenburg in a major urologic surgery is associated with postoperative delirium, and to examine other potential clinical and radiologic factors predictive of postoperative delirium. METHODS: 182 patients who received a major urologic surgery and underwent a 3.0-T brain MRI scan within 1 year prior to the date of surgery were retrospectively enrolled. Preoperative brain MRIs were used to analyze features related to small vessel disease burden and mesial temporal atrophy. Presence of a significant mesial temporal atrophy was defined as Scheltens' scale ≥ 2. Patients' clinico-demographic data and MRI features were used to identify significant predictors of postoperative delirium using the logistic regression analysis. Independent predictors found significant in the univariate analysis were further evaluated in the multivariate analysis. RESULTS: Incidence of postoperative delirium was 6.0%. Patients with postoperative delirium had lower body mass index (21.3 vs. 25.0 kg/m2, P = 0.003), prolonged duration of anesthesia (362.7 vs. 224.7 min, P < 0.001) and surgery (302.2 vs. 174.5 min, P < 0.001), and had more significant mesial temporal atrophy (64% vs. 30%, P = 0.046). In the univariate analysis, female sex, type of surgery (radical prostatectomy over cystectomy), prolonged duration of anesthesia (≥ 6 h), and presence of a significant mesial temporal atrophy were significant predictors (all P-values < 0.050), but only the presence of significant mesial temporal atrophy was significant in the multivariate analysis [odds ratio (OR), 3.69; 95% CI 0.99-13.75; P = 0.046]. CONCLUSION: Steep Trendelenburg was not associated with postoperative delirium. Significant mesial temporal atrophy (Scheltens' scale ≥ 2) in preoperative brain MRI was predictive of postoperative delirium. TRIAL REGISTRATION: Not applicable.

Advances in the Clinical Application of Trendelenburg Position.

The Trendelenburg position and reverse Trendelenburg position are frequently employed during lower abdominal surgery to achieve optimal surgical field visualization and complete exposure of the operative site, particularly under pneumoperitoneum conditions. However, these positions can have significant impacts on the patient's physiological functions. This article overviews the historical background of Trendelenburg position and reverse Trendelenbury position, their effects on various physiological functions, recent advancements in their clinical applications, and strategies for preventing and managing associated complications.

A new position utilizing the effect of gravity in proximal ureteral stones, ureteroscopic lithotripsy in the reverse Trendelenburg position: a prospective, randomized, comparative study.

PURPOSE: To evaluate the effect of the reverse Trendelenburg position in patients undergoing ureteroscopic lithotripsy for proximal ureteral stones. METHODS: The study included 167 patients who underwent ureteroscopic lithotripsy for proximal ureter stones between December 2020 and September 2022. The patients were randomly assigned to one of three groups: standard lithotomy (n:55), 10° reverse Trendelenburg (n:55), and 20° reverse Trendelenburg (n:57). Preoperative information, including age, sex, body mass index (BMI), previous shock wave lithotripsy (SWL), stone side, volume, and density, distance to the ureteropelvic junction (UPJ) of the stone, and hydronephrosis degree. Stone-free status was evaluated with computed tomography (CT) at 4 weeks postoperatively. The groups were compared in respect of stone migration, stone-free rate, use of flexible ureterorenoscope, operating time, postoperative length of stay in the hospital, and complications. RESULTS: No statistically significant difference was determined between the groups with respect to age, sex, BMI, previous SWL, stone side, volume and density, distance to the UPJ of the stone, and hydronephrosis degree (p > 0.05 for all). Statistically significant differences were determined between the groups with respect to stone migration (p = 0.001), stone-free rate (p < 0.001), use of flexible ureterorenoscope (p = 0.01), operating time (p < 0.001), hospital length of stay (p < 0.001), postoperative fever (p = 0.002), and total complications (p = 0.01). CONCLUSION: A new patient position is presented in this study, which can be used in ureteroscopic lithotripsy performed for proximal ureteral stones. The reverse Trendelenburg position constitutes a surgical method that can be used safely and successfully in the treatment of proximal ureteral stones. TRIAL REGISTRATION NUMBER: NCT04894058, 05/21/2021, Prospectively registered.

Effects of individualised positive end-expiratory pressure titration on respiratory and haemodynamic parameters during the Trendelenburg position with pneumoperitoneum: A randomised crossover physiologic trial.

BACKGROUND: The Trendelenburg position with pneumoperitoneum during surgery promotes dorsobasal atelectasis formation, which impairs respiratory mechanics and increases lung stress and strain. Positive end-expiratory pressure (PEEP) can reduce pulmonary inhomogeneities and preserve end-expiratory lung volume (EELV), resulting in decreased inspiratory strain and improved gas-exchange. The optimal intraoperative PEEP strategy is unclear. OBJECTIVES: To compare the effects of individualised PEEP titration strategies on set PEEP levels and resulting transpulmonary pressures, respiratory mechanics, gas-exchange and haemodynamics during Trendelenburg position with pneumoperitoneum. DESIGN: Prospective, randomised, crossover single-centre physiologic trial. SETTING: University hospital. PATIENTS: Thirty-six patients receiving robot-assisted laparoscopic radical prostatectomy. INTERVENTIONS: Randomised sequence of three different PEEP strategies: standard PEEP level of 5 cmH 2 O (PEEP 5 ), PEEP titration targeting a minimal driving pressure (PEEP ΔP ) and oesophageal pressure-guided PEEP titration (PEEP Poeso ) targeting an end-expiratory transpulmonary pressure ( PTP ) of 0 cmH 2 O. MAIN OUTCOME MEASURES: The primary endpoint was the PEEP level when set according to PEEP ΔP and PEEP Poeso compared with PEEP of 5 cmH 2 O. Secondary endpoints were respiratory mechanics, lung volumes, gas-exchange and haemodynamic parameters. RESULTS: PEEP levels differed between PEEP ΔP , PEEP Poeso and PEEP5 (18.0 [16.0 to 18.0] vs. 20.0 [18.0 to 24.0]vs. 5.0 [5.0 to 5.0] cmH 2 O; P  < 0.001 each). End-expiratory PTP and lung volume were lower in PEEP ΔP compared with PEEP Poeso ( P  = 0.014 and P  < 0.001, respectively), but driving pressure, lung stress, as well as respiratory system and dynamic elastic power were minimised using PEEP ΔP ( P  < 0.001 each). PEEP ΔP and PEEP Poeso improved gas-exchange, but PEEP Poeso resulted in lower cardiac output compared with PEEP 5 and PEEP ΔP . CONCLUSION: PEEP ΔP ameliorated the effects of Trendelenburg position with pneumoperitoneum during surgery on end-expiratory PTP and lung volume, decreased driving pressure and dynamic elastic power, as well as improved gas-exchange while preserving cardiac output. TRIAL REGISTRATION: German Clinical Trials Register (DRKS00028559, date of registration 2022/04/27). https://drks.de/search/en/trial/DRKS00028559.

Effect of Individualized PEEP on Perioperative Pulmonary Complications in Elderly Patients with Prostate Cancer Undergoing General Anesthesia in Trendelenburg Position: A Single-Center Retrospective Study.

OBJECTIVE: This study aimed to explore the effect of individualized positive end-expiratory pressure (PEEP) on postoperative pulmonary complications (PPCs) in elderly patients with prostate cancer undergoing general anesthesia in Trendelenburg position (low-head and high-foot position at about 45° when patients were in supine position). METHODS: The clinical data of 96 elderly patients undergoing Leonardo's robotic-assisted laparoscopic radical prostatectomy in Zhejiang Provincial People's Hospital from October 2021, to April 2023, were selected for retrospective analysis. Sixteen patients who had interrupted follow-up or did not meet the inclusion criteria were excluded, and 80 patients were finally included. The patients were divided into group A (lung-protective strategy using routine PEEP value, n = 40) and group B (lung-protective strategy using individualized PEEP value, n = 40) on the basis of different inversion methods. The PEEP value of group A was set as 5 cmH2O, whereas that of group B was determined under the guidance of static lung compliance. The incidences of PPCs on postoperative day 7 were statistically analyzed, and the serum levels of interleukin (IL) 6 (IL-6) and IL-8 in both groups were measured by enzyme-linked immunoadsordent assay (ELISA). RESULTS: The incidence of pulmonary complications was obviously lower in group B than in group A on postoperative day 7 (p < 0.001). Group B had lower levels of serum IL-6 and IL-8 at the end of surgery (T1) and 12 h after surgery (T2, p < 0.001); Higher oxygenation index values 10 min after successful titration of individualized PEEP (A3), 1 h after individualized PEEP ventilation (A4), 2 h after individualized PEEP ventilation (A5), 10 min after recovery of supine position (A6), and 30 min after tracheal extubation (A7); And lower hospitalization time (all p < 0.001) than group A. CONCLUSIONS: Individualized PEEP for elderly patients with prostate cancer undergoing general anesthesia in Trendelenburg position effectively relieves the release of inflammatory factors, reduces the occurrence of PPCs, and shortens hospitalization time. Thus, it is an effective protection strategy and has certain clinical value.

Effect of the reverse Trendelenburg position on the incidence of gastroesophageal reflux in dogs anesthetized for elective stifle surgery.

OBJECTIVE: To determine if a 15° reverse Trendelenburg position decreases the incidence of gastroesophageal reflux (GER) compared with a horizontal position in dogs anesthetized for stifle surgery. STUDY DESIGN: Prospective, randomized parallel-arm study. ANIMALS: A total of 44 healthy client-owned dogs were enrolled and data from 36 dogs were analyzed. METHODS: Dogs requiring preoperative radiographs under anesthesia, or with a history of gastrointestinal signs or administered gastroprotectant therapy within 1 month of surgery were excluded. Anesthesia protocol was standardized to include hydromorphone, dexmedetomidine, ketamine, propofol and isoflurane. Dogs were randomly assigned at enrollment to be positioned in a 15° reverse Trendelenburg or a horizontal position for surgery. Continuous pH monitoring was documented throughout the procedure with a 6.4 Fr (2.13 mm) esophageal pH probe positioned in the distal esophagus via the oral cavity. GER was defined as pH < 4.0 (acidic) or > 7.5 (alkaline) for more than 30 seconds. The proportions of dogs developing GER were compared between groups using Fisher's exact test. Time to reflux was compared using survival curves and the Gehan-Breslow-Wilcoxon test. Statistical significance was set as p < 0.05. RESULTS: An episode of GER occurred in 11/36 (30%) dogs. Reflux was alkaline in two dogs and acidic in nine dogs. The proportion of dogs with GER was 5/18 (28%) and 6/18 (33%) for dogs in the reverse Trendelenburg position and horizontal position, respectively, and was not statistically significant (p > 0.99). Median (range) time until reflux was 44 (23-135) and 44.5 (9-56) minutes when dogs were positioned in reverse Trendelenburg position and horizontal position, respectively (p = 0.66; two-tailed Mann-Whitney U test). CONCLUSIONS AND CLINICAL RELEVANCE: Positioning the surgery table in a 15° rostral elevation for dogs anesthetized for elective stifle surgical procedures did not decrease the incidence of GER.

Effects of antioxidant supplementation on bone mineral density, bone mineral content and bone structure in healthy men during 60 days of 6° head-down tilt bed rest: Results from a randomised controlled trial.

Dietary countermeasures to mitigate detrimental spaceflight-induced effects on bone health would alleviate the requirements and the consequences imposed by other types of countermeasures for this risk. We hypothesised that antioxidant supplementation during 60 days of 6° head-down tilt bed rest (HDBR), an analogue of spaceflight, would have a protective effect on bone mineral density (BMD), content (BMC) and bone structure parameters. An exploratory, randomised, controlled, single-blind intervention trial was conducted in a parallel design with 20 healthy male volunteers (age 34 ± 8 y, weight 74 ± 6 kg). The study included 14 days of baseline data collection (BDC) before bed rest, followed by 60 days of HDBR and a 14-day recovery period. Ten subjects in the antioxidant group received a supplement (741 mg/d polyphenols, 2.1 g/d omega-3 fatty acids, 168 mg/d vitamin E and 80 µg/d selenium) daily. Ten subjects in the control group received no supplement. The diet was consistent with dietary reference intakes, individually tailored based on the subject's bodyweight and strictly controlled. We measured whole-body, lumbar spine and femur BMD and BMC, as well as BMD of the cortical and trabecular compartments of the distal radius and tibia, and cortical and trabecular thickness during BDC, HDBR and recovery. Data were analysed using linear mixed models. The supplementation of an antioxidant cocktail did not mitigate the deteriorating effects of HDBR on BMD, BMC and bone structure parameters. Our findings do not support a recommendation for antioxidant supplementation for astronauts.

Effect of expiratory flow limitation on ventilation/perfusion mismatch and perioperative lung function during pneumoperitoneum and Trendelenburg position.

BACKGROUND: Laparoscopic surgery and Trendelenburg position may affect the respiratory function and alter the gas exchange. Further the reduction of the lung volumes may contribute to the development of expiratory flow limitation (EFL). The latter is associated with an increased risk of postoperative pulmonary complications. Our aim was to investigate the incidence of EFL and to evaluate its effect on pulmonary function and intraoperative V/Q mismatch. METHODS: This is a prospective study on patients undergoing elective laparoscopic gynecological surgery. We evaluated respiratory mechanics, V/Q mismatch and presence of EFL after anesthesia induction, during pneumoperitoneum and Trendelenburg position and at the end of surgery. Intraoperative gas exchange and hemodynamic were also recorded. Clinical data were collected until seven days after surgery to evaluate the onset of pulmonary postoperative complications (PPCs). RESULTS: Among the 66 patients enrolled, 25/66 (38%) exhibited EFL during surgery, of whom 10/66 (15%) after anesthesia induction, and the remaining 15 patients after pneumoperitoneum and Trendelenburg position. Median PEEP able to reverse flow limitation was 7 [7-10] cmH2O after anesthesia induction and 9 [8-15] cmH2O after pneumoperitoneum and Trendelenburg position. Patients with EFL had significantly higher shunt (17 [2-25] vs. 9 [1-19]; P=0.05), low V̇/Q̇ (27 [20-70] vs. 15 [10-22]; P=0.05) and high V̇/Q̇ (10 [7-14] vs. 6 [4-7]; P=0.024). At the end of surgery, only high V/Q was significantly higher in EFL patients. Further, they exhibited higher incidence of postoperative pulmonary complication (48% (12/25) vs. 15% (6/41), P=0.005), hypoxemia and hypercapnia (80% [20/25] vs. 32% [13/41]; P<0.001). CONCLUSIONS: Expiratory flow limitation is a common phenomenon during gynecological laparoscopic surgery associated with worsen gas exchange, increased V/Q mismatch and altered lung mechanics. Our study showed that patients experiencing EFL during surgery showed a higher risk for PPCs.

Electric impedance tomography and protective mechanical ventilation in elective robotic-assisted laparoscopy surgery with steep Trendelenburg position: a randomized controlled study.

Electrical impedance tomography (EIT) reconstructs functional lung images and evaluates the variations of impedance during the breathing cycle. The aim of this study was to evaluate the effect of protective mechanical ventilation on ventilation distributions recorded by the EIT during elective robotic-assisted laparoscopy surgery with steep Trendelenburg position. This prospective, randomized single center study included patients with healthy lungs undergoing elective robot-assisted laparoscopic urological surgery in general anesthesia. Patients were randomly assigned to either protective lung ventilation or conventional ventilation. In the protective ventilation group, tidal volume (TV) was set at 6 ml/Kg predicted body weight (PBW), with PEEP 6 cmH2O, and recruitment maneuvers (RM) as needed. In the conventional ventilation group, TV was set at 9 ml/Kg PBW, with PEEP 2 cmH2O and RM only as needed. Ventilation distribution was assessed using an EIT device. This study included 40 patients in the functional image analysis. Significant differences were found in ventilation distribution in the region of interest (p < 0.05). Driving pressure was significantly lower in protective ventilation group (p < 0.05). Peak and plateau pressures were not different between the groups while statical significance was found in tidal volume and respiratory rate. EIT may be a valuable tool for monitoring lung function during general anesthesia. During elective robotic-assisted laparoscopy surgery with steep Trendelenburg position, protective mechanical ventilation may have a more homogenous distribution of intraoperative and postoperative ventilation. Larger sample size and long-term evaluation are needed in future studies to assess the benefit of EIT monitoring in operation room.Clinical trial registration ClinicalTrials.gov Identifier: NCT04194177 registered at 11th December 2019.

Minimizing Lung Injury During Laparoscopy in Head-Down Tilt: A Physiological Cohort Study.

BACKGROUND: Increased intra-abdominal pressure during laparoscopy induces atelectasis. Positive end-expiratory pressure (PEEP) can alleviate atelectasis but may cause hyperinflation. Cyclic opening of collapsed alveoli and hyperinflation can lead to ventilator-induced lung injury and postoperative pulmonary complications. We aimed to study the effect of PEEP on atelectasis, lung stress, and hyperinflation during laparoscopy in the head-down (Trendelenburg) position. METHODS: An open-label, repeated-measures, interventional, physiological cohort trial was designed. All participants were recruited from a single tertiary Belgian university hospital. Twenty-three nonobese patients scheduled for laparoscopy in the Trendelenburg position were recruited.We applied a decremental PEEP protocol: 15 (high), 10 and 5 (low) cm H 2 O. Atelectasis was studied with the lung ultrasound score, the end-expiratory transpulmonary pressure, the arterial oxygen partial pressure to fraction of inspired oxygen concentration (P ao2 /Fi o2 ) ratio, and the dynamic respiratory system compliance. Global hyperinflation was evaluated by dead space volume, and regional ventilation was evaluated by lung ultrasound. Lung stress was estimated using the transpulmonary driving pressure and dynamic compliance. Data are reported as medians (25th-75th percentile). RESULTS: At 15, 10, and 5 cm H 2 O PEEP, the respective measurements were: lung ultrasound scores (%) 11 (0-22), 27 (11-39), and 53 (42-61) ( P < .001); end-expiratory transpulmonary pressures (cm H 2 O) 0.9 (-0.6 to 1.7), -0.3 (-2.0 to 0.7), and -1.9 (-4.6 to -0.9) ( P < .001); P ao2 /Fi o2 ratios (mm Hg) 471 (435-538), 458 (410-537), and 431 (358-492) ( P < .001); dynamic respiratory system compliances (mL/cm H 2 O) 32 (26-36), 30 (25-34), and 27 (22-30) ( P < .001); driving pressures (cm H 2 O) 8.2 (7.5-9.5), 9.3 (8.5-11.1), and 11.0 (10.3-12.2) ( P < .001); and alveolar dead space ventilation fractions (%) 10 (9-12), 10 (9-12), and 9 (8-12) ( P = .23). The lung ultrasound score was similar between apical and basal lung regions at each PEEP level ( P = .76, .37, and .76, respectively). CONCLUSIONS: Higher PEEP levels during laparoscopy in the head-down position facilitate lung-protective ventilation. Atelectasis and lung stress are reduced in the absence of global alveolar hyperinflation.

Lower leg blood pressure decreases while calf external pressure increases with the angulation of the Trendelenburg position in the lithotomy position with calf- and foot-supported leg holders.

Patients who underwent lower abdominopelvic surgeries in the lithotomy position (LP) and the Trendelenburg position (TP) with the leg holder are at risk of developing well leg compartment syndrome (WLCS). However, contributing factors related to the LP with TP associated with WLCS are unknown. This study aimed to investigate the associations between external pressure at the calf in the LPs at different angulations of the TP and physiological characteristics. Eighty-four university students (age, 21.7 ± 0.9; 42 men and 42 women) voluntarily participated in the study. The awake participants were placed in the LPs using the calf- and foot-supported leg holder at 0° (horizontal level), 5°, 10°, and 20° head-down tilts by moving the electric operating table. The peak contact pressure (pCP) was measured at the calf as a representative external pressure using the pressure distribution measurement system BIG-MAT®. Lower leg blood pressure significantly decreased with TP angulation, while calf pCP significantly increased with it at 0°, 5°, 10°, and 20° head-down tilts (39.4 ± 15.2, 46.5 ± 17.7, 47.2 ± 16.9, and 50.3 ± 17.6 mmHg, respectively). The calf pCP with a 10° head-down tilt was correlated positively with the calf total force (P < 0.001) and negatively with the calf contact area (P < 0.001). Blood hypoperfusion due to low lower leg blood pressure secondary to lower leg elevation and head-down tilt, and high calf external pressure due to direct external compression from the leg holder where it is loaded may contribute to WLCS.

Transoral robotic surgery in a modified Trendelenburg position for oropharyngeal squamous cell carcinoma in a patient with severe thoracic kyphosis.

BACKGROUND: Excessive flexion of the neck and upper back from severe kyphosis of the thoracic spine may limit treatment options for head and neck cancer (HNC). METHODS: We describe an innovative approach to transoral robotic surgery (TORS) in a patient with severe thoracic kyphosis and oropharyngeal squamous cell carcinoma (OPSCC) who was unsuitable for definitive radiotherapy. RESULTS: Detailed discussion of management pathway, perioperative considerations, and surgical challenges is presented. TORS lateral oropharyngectomy was successfully performed with the robotic system docked from the caudal end in a modified Trendelenburg position. CONCLUSIONS: With appropriate surgical and anesthetic planning, TORS for patients with severe thoracic kyphosis is a feasible and suitable treatment.

The complexity analysis of cerebral oxygen saturation during pneumoperitoneum and Trendelenburg position: a retrospective cohort study.

BACKGROUND: The human brain is a highly complex and nonlinear system, nonlinear complexity measures such as approximate entropy (ApEn) and sample entropy (SampEn) can better reveal characteristics of brain dynamics. However, no studies report complexity of perioperative physiological signals to reveal how brain complexity associates with age, varies along with the development of surgery and postoperative neurological complications. AIM: This study examined the complexity of intraoperative regional cerebral oxygen saturation (rSO2), aiming to reveal brain dynamics during surgery. METHODS: This retrospective cohort study enrolled patients who scheduled for robot-assisted urological surgery. Intraoperative rSO2 was continuously monitored throughout the surgery. Postoperative delirium (POD) was diagnosed by the Confusion Assessment Method. ApEn and SampEn were used to characterize the complexity of rSO2. Pearson correlation coefficients were used to measure the correlation between complexity of rSO2 and age. The association between complexity of rSO2 and POD was examined using T tests. RESULTS: A total of 68 patients (mean [SD] age, 63.0 (12.0) years; 47 (69.1%) males) were include in this analysis. There was a significant reverse relationship between the complexity of rSO2 and age (The correlation coefficients range between - 0.32 and - 0.28, all p < 0.05). Patients ≥ 75 years showed significantly lower complexity of rSO2 than the other two groups. Older age remained an independent factor influencing complexity of rSO2 after adjusting for a number of covariates. Six patients (8.8%) developed POD, and POD patients had lower complexity of rSO2 compared with non-POD patients. CONCLUSIONS: The complexity of rSO2 may serve as a new candidate marker of aging and POD prediction.

Relationships between common carotid artery blood flow and anesthesia, pneumoperitoneum, and head-down tilt position: a linear mixed-effect analysis.

This study investigated the effects of pneumoperitoneum and the head-down tilt position on common carotid artery (CCA) blood flow in surgical patients. METHODS: This prospective observational study included 20 patients who underwent gynecological surgery. CCA blood flow was measured using Doppler ultrasound at four-time points: awake in the supine position [T1], 3 min after anesthesia induction in the supine position [T2], 3 min after pneumoperitoneum in the supine position [T3], and 3 min after pneumoperitoneum in the head-down tilt position [T4]. Hemodynamic and respiratory parameters were also recorded at each time point. Linear mixed-effect analyses were performed to compare CCA blood flow across the time points and assess its relationship with hemodynamic parameters. RESULTS: Compared with T1, CCA blood flow decreased significantly at T2 (345.4 [288.0-392.9] vs. 293.1 [253.0-342.6], P = 0.048). CCA blood flow were also significantly lower at T3 and T4 compared with T1 (345.4 [288.0-392.9] vs. 283.6 [258.8-307.6] and 287.1 [242.1-321.4], P = 0.005 and 0.016, respectively). CCA blood flow at T3 and T4 did not significantly differ from that at T2. Changes in CCA blood flow were significantly associated with changes in cardiac index and stroke volume index (P = 0.011 and 0.024, respectively). CONCLUSION: CCA blood flow was significantly decreased by anesthesia induction. Inducing pneumoperitoneum, with or without the head-down tilt position, did not further decrease CCA blood flow if the cardiac index remained unchanged. The cardiac index and stroke volume index were significantly associated with CCA blood flow. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov (NCT04233177, January 18, 2020).