Upper extremity contact pressure measurement in robot-assisted pelvic surgery

Upper extremity complications are often a problem in robot-assisted pelvic surgery (RAPS) with the lithotomy-Trendelenburg position (LT-position). This study focused on upper extremity contact pressure (UEP) and examined the relationship between UEP and upper extremity complications. From May 2020 to April 2022 at the University of Tokyo Hospital, UEP was measured in 155 patients undergoing RARP and 20 patients undergoing RARC. A total of 350 sets of UEP were investigated in this study. UEP was measured using a portable interface pressure sensor (Palm Q, Cape CO., Kanagawa, Japan) in the preoperative lithotripsy position (L-position), preoperative LT-position, and postoperative L-position. UEP was increased in the preoperative LT-position than in the preoperative L-position (right side 5.2 mmHg vs. 17.1 mmHg, left side 5.3 mmHg vs. 17.1 mmHg, P < 0.001, respectively), and was decreased in the postoperative L-position than in preoperative LT-position (right side 17.1 mmHg vs. 10.8 mmHg, left side 17.1 mmHg vs. 10.6 mmHg, P < 0.001, respectively). Eleven upper extremities developed shoulder pain. UEP of the preoperative LT-position tended to be higher in the upper extremity exhibiting shoulder pain (25.6 mmHg (15.4-30.3) vs. 17.1 mmHg (12.0-24.4) P = 0.0901). UEP measurements may help prevent postoperative shoulder pain.

Role of oxygen reserve index monitoring in patients undergoing robot-assisted radical prostatectomy: a retrospective study

PURPOSE

Robot-assisted radical prostatectomy (RARP) is a common surgical procedure for the treatment of prostate cancer. Although beneficial, it can lead to intraoperative hypoxia due to high-pressure pneumoperitoneum and Trendelenburg position. This study explored the use of oxygen reserve index (ORi) to monitor and predict hypoxia during RARP.

METHODS

A retrospective analysis was conducted on 329 patients who underwent RARP at the Seoul National University Bundang Hospital between July 2021 and March 2023. Various pre- and intraoperative variables were collected, including ORi values. The relationship between ORi values and hypoxia occurrence was assessed using receiver operating characteristic curves and logistic regression analysis.

RESULTS

Intraoperative hypoxia occurred in 18.8% of the patients. The receiver operating characteristic curve showed a satisfactory area under the curve of 0.762, with the ideal ORi cut-off value for predicting hypoxia set at 0.16. Sensitivity and specificity were 64.5% and 75.7%, respectively. An ORi value of < 0.16 and a higher body mass index were identified as independent risk factors of hypoxia during RARP.

CONCLUSIONS

ORi monitoring provides a non-invasive approach to predict intraoperative hypoxia during RARP, enabling early management. Additionally, the significant relationship between a higher body mass index and hypoxia underscores the importance of individualized patient assessment.

Experimental assessment of pelvis slipping during postless traction for orthopaedic applications

BACKGROUND

The application of lower limb traction during hip arthroscopy and femur fractures osteosynthesis is commonplace in orthopaedic surgeries. Traditional methods utilize a perineal post on a traction table, leading to soft tissue damage and nerve neuropraxia. A postless technique, using high-friction pads, has been considered as a potential damage-free alternative. However, whether these pads sufficiently prevent patient displacement remains unknown. Thus, this study systematically assesses the efficacy of commercial high-friction pads (PinkPad and CarePad) in restraining subject displacement, for progressively increasing traction loads and different Trendelenburg angles.

METHODS

Three healthy male subjects were recruited and tested in supine and Trendelenburg positions (5° and 10°), using a customized boot-pulley system. Ten load disks (5 kg) were dropped at 15s intervals, increasing gradually the traction load up to 50 kg. Pelvis displacement along the traction direction was measured with a motion capture system. The displacement at 50 kg of traction load was analyzed and compared across various pads and bed inclinations. Response to varying traction loads was statistically assessed with a quadratic function model.

RESULTS

Pelvis displacement at 50 kg traction load was below 60 mm for all conditions. Comparing PinkPad and CarePad, no significant differences in displacement were observed. Finally, similar displacements were observed for the supine and Trendelenburg positions.

CONCLUSIONS

Both PinkPad and CarePad exhibited nearly linear behavior under increasing traction loads, limiting displacement to 60 mm at most for 50 kg loads. Contrary to expectations, placing subjects in the Trendelenburg position did not increase adhesion.

Acute Coronary Artery Air Embolism Complicating a CT-guided percutaneous lung biopsy: A case report

Systemic air embolism is a fatal complication of computed tomography-guided percutaneous lung biopsy. Here, we report a case of acute coronary artery air embolism following computed tomography (CT) guided percutaneous lung biopsy. The patient exhibited cardiac symptoms, and CT showed air density in left ventricle and aorta, indicating air embolism. Trendelenburg positioning and coronary angiography were performed during the treatment, and the patient was discharged without obvious complications.

Hypoxemia of the lower limbs during robot-assisted radical prostatectomy in Trendelenburg position

Objectives

The objective of this study is to assess frequency and risk factors for intraoperative hypoxemia of the lower limbs during robot-assisted radical prostatectomy (RARP). Trendelenburg position during RARP may contribute to hypoxemia and compartment syndrome (CS) of the lower limbs as a major but rare complication.

Patients and methods

This prospective study included patients undergoing RARP for prostate cancer. Preoperative calculation of the ankle-brachial-index (ABI) was performed. Peripheral oxygen saturation (SpO2) at the toes was routinely measured. Occurrence of SpO2 levels of <90% was defined as hypoxemic events and treated immediately. Blood pressure, intraabdominal pressure, SpO2 of the upper limb and surgery time were monitored in case of hypoxemia. A multivariable logistic regression model was performed with age, BMI, nicotine abuse, MAP, comorbidities as covariates and hypoxemia of the lower limbs as the outcome.

Results

A total of 207 patients were included. Among these, 126 patients had ABI measurements with 10.6% having an abnormal ABI value. One, two or at least three events of lower limb hypoxemia occurred intraoperatively in 19.7%, 14.8% and 16.9%, respectively. In 20 events, surgical instruments were affecting vascular perfusion by compression. None of the covariates were statistically significant associated with lower limb hypoxemia. No patient developed a compartment syndrome.

Conclusion

Decrease in oxygen saturation of the lower extremities was observed frequently during RARP, without revealing any risk factors for its occurrence. Routine oximetry leads to an early detection of hypoxemia of the lower extremities, giving the anaesthesiologist and surgeon the opportunity to make adequate adjustments (increasing blood pressure and ending iliac vessel compression).

Postoperative vision loss due to bilateral vitreous hemorrhage after robot-assisted laparoscopic hysterectomy: A case report

Purpose

To report a case of bilateral vitreous hemorrhage (VH) resulting in postoperative vision loss (POVL) after robot-assisted laparoscopic hysterectomy in a 71-year-old female patient.

Observations

At initial presentation, best-corrected visual acuity was hand motion at 20 cm in the right eye and 20/666 in the left eye. VH in both eyes and preretinal hemorrhage in the left eye was observed. As the hemorrhage gradually resolved, a full-thickness macular hole was discovered in the right eye, for which the patient did not agree with a surgical treatment.

Conclusions and importance

This report describes a rare incidence of bilateral VH as a cause of POVL after non-ophthalmic surgery, which may be related to Trendelenburg positioning, CO2 pneumoperitoneum, and a long surgical duration. Given that POVL can cause severe visual impairment, consultation with ophthalmologists is crucial.

Airway leakage due to malpositioning of esophageal temperature probe during robot-assisted radical prostatectomy: a case report

Measuring patients' core body temperature during surgery is essential and commonly performed with an esophageal temperature probe. The probe must be placed in the lower third of the esophagus for accurate measurement. In this case report, we describe our experience of discovering an inadvertently malpositioned esophageal temperature probe in the right inferior lobar bronchus, which led to ventilation-related problems in a patient undergoing prostate surgery.

Measuring intraoperative anesthetic parameters during hepatectomy with inferior vena cava clamping

PURPOSE

Uncontrollable bleeding remained problematic in anatomical hepatectomy exposing hepatic veins. Based on the inferior vena cava (IVC) anatomy, we attempted to analyze the hemodynamic and surgical effects of the combined IVC-partial clamp (PC) accompanied with the Trendelenburg position (TP).

METHODS

We prospectively assessed 26 consecutive patients who underwent anatomical hepatectomies exposing HV trunks between 2020 and 2023. Patients were divided into three groups: use of IVC-PC (group 1), no use of IVC-PC (group 2), and use of IVC-PC accompanied with TP (group 3). In 10 of 26 patients (38%), hepatic venous pressure was examined using transhepatic catheter insertion.

RESULTS

IVC-PC was performed in 15 patients (58%). Operating time and procedures did not significantly differ between groups. A direct hemostatic effect on hepatic veins was evaluated in 60% and 70% of patients in groups 1 and 3, respectively. Group 1 showed significantly more unstable vital status and vasopressor use (p < 0.01). Blood or fluid transfusion and urinary output were similar between groups. Group 2 had a significantly lower baseline central venous pressure (CVP), while group 3 showed a significant increase in CVP in TP. CVP under IVC-PC seemed lower than under TP; however, not significantly. Hepatic venous pressure did not significantly differ between groups. Systolic arterial blood pressure significantly decreased via IVC-PC in group 1 and to a similar extent in group 3. Heart rate significantly increased during IVC-PC (p < 0.05).

CONCLUSION

IVC-PC combined with the TP may be an alternative procedure to control intrahepatic venous bleeding during anatomical hepatectomy exposing hepatic venous trunks.

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 secondary daily persistent headache from onset with underlying nutcracker physiology and spinal epidural venous congestion: case series with lumbar vein embolization as a therapeutic approach

The authors have published on a unique subset of patients whose headaches worsened in the Trendelenburg position and who on time-resolved MR angiography demonstrated left renal vein compression (nutcracker physiology) with retrograde left second lumbar vein (L2LV) flow and regional spinal epidural venous plexus (EVP) congestion. We hypothesized that the spinal EVP congestion subsequently causes a secondary congestion of the cerebral venous system, which then leads to an elevation of CSF pressure above that individuals CSF pressure set point. This results in a daily headache from onset. Thus, eliminating the spinal EVP could conceivably improve or eliminate the manifested headache syndrome. We now present a case series of four patients with long-term follow-up utilizing lumbar vein coil embolization as a new therapeutic approach. In each patient, the MR angiography findings were verified by catheter-based venography. Treatment consisted of endovascular embolization of the second lumbar vein. Four patients have had coil embolization of which three are 1 year or longer from their procedure while one is 10 months posttreatment. All patients were women. Duration of daily headache prior to embolization ranged from 4 to 8 years. Post-embolization: Three patients are either headache free or 90-95% improved with substantial pain free time. There were no procedure-related complications. Our results suggest that embolization of L2LV in a specific patient population with nutcracker physiology may substantially improve head pain issues. This is a minimally invasive outpatient technique with no apparent side effects.

Ultrasonographic evaluation of diaphragmatic excursion changes after major laparoscopic surgeries in the Trendelenburg position under general anaesthesia: A prospective observational study

Background and Aims

Laparoscopic surgeries result in increased intra abdominal pressure and cephalad displacement of the diaphragm. The Trendelenburg position can augment these respiratory changes. The primary objective of this study was to compare diaphragmatic excursions before and after a major laparoscopic pelvic surgery under general anaesthesia in the Trendelenburg position using ultrasonography (USG).

Methods

This prospective observational study included 90 patients of either gender, aged 20-60 years, with American Society of Anesthesiologists physical status I/II. M-mode USG was used to assess diaphragm inspiratory amplitude (DIA) before induction of anaesthesia and 10 minutes after tracheal extubation. Factors such as age, gender, body mass index, positive end-expiratory pressure (PEEP), pain, peak airway pressures, duration of pneumoperitoneum, duration and degree of Trendelenburg position and duration of anaesthesia were recorded. Pearson's correlation and multiple linear regression were used to analyse the factors affecting change in DIA (ΔDIA).

Results

The mean difference (95% confidence interval (CI)) of measured DIA was 0.70 (0.598-0.809), P < 0.001. ΔDIA had a weak positive significant correlation with age, anaesthesia duration, pneumoperitoneum, and visual analogue scale (VAS) score 10 minutes after extubation. Multiple linear regression analysis showed 14.86% of the variance in DIA. Age (β = 0.008, P = 0.049), duration of anaesthesia (β = 0.002, P = 0.02) and VAS score 10 minutes after extubation (β = 0.128, P = 0.001) were significant independent predictors.

Conclusion

DIA decreased significantly after pelvic laparoscopic surgeries performed in the Trendelenburg position. Age, duration of anaesthesia and pain after the procedure were significant independent predictors.

[Effect of preoperative carbohydrates intake on the gastric volume and the risk of reflux aspiration in patients positioning in trendelenburg undergoing gynecological laparoscopic procedures]

OBJECTIVE

To investigate the effect of 300 mL carbohydrates intake two hours before sur-gery on the gastric volume (GV) in patients positioning in trendelenburg undergoing gynecological laparoscopic procedures by using gastric antrum sonography, and further assess the risk of reflux aspiration.

METHODS

From June 2020 to February 2021, a total of 80 patients, aged 18-65 years, body mass index (BMI) 18-35 kg/m2, falling into American Society of Anesthesiologists (ASA) physical status Ⅰ or Ⅱ, scheduled for gynecological laparoscopic procedures positioning in trendelenburg were recruited and divided into two groups: the observation group (n =40) and the control group (n=40). In the observation group, solid food was restricted after 24:00, the patients were required to take 300 mL carbohydrates two hours before surgery. In the control group, solid food and liquid intake were restricted after 24:00 the night before surgery. The cross-sectional area (CSA) of gastric antrum was measured in supine position and right lateral decubitus position before anesthesia. Primary outcome was gastric volume (GV) in each group. Secondary outcome included Perlas A semi-quantitative grading and gastric volume/weight (GV/W). All the patients received assessment of preoperative feeling of thirsty and hunger with visual analogue scale (VAS).

RESULTS

Complete data were available in eighty patients. GV was (58.8±23.6) mL in the intervention group vs. (56.3±22.1) mL in the control group, GV/W was (0.97±0.39) mL/kg vs. (0.95±0.35) mL/kg, respectively; all the above showed no significant difference between the two groups (P > 0.05). Perlas A semi-quantitative grading showed 0 in 24 patients (60%), 1 in 15 patients (37.5%), 2 in 1 patient (2.5%) in the intervention group and 0 in 25 (62.5%), 1 in 13 (32.5%), 2 in 2 (5%) in the control group, the proportion of Perlas A semi-quantitative grading showed no significant difference between the two groups (P > 0.05). A total of 3 patients (1 in the intervention group and 2 in the control group) with Perlas A semi-quantitative grading 2 were treated with special intervention, no aspiration case was observed in this study. The observation group endured less thirst and hunger (P＜0.05).

CONCLUSION

Three hundred mL carbohydrates intake two hours before surgery along with ultrasound guided gastric content monitoring does not increase gastric volume and the risk of reflux aspiration in patients positioning in trendelenburg undergoing gynecological laparoscopic surgery, and is helpful in minimizing disturbance to the patient's physiological needs, therefore leading to better clinical outcome.

Optimal positive end-expiratory pressure titration of intraoperative mechanical ventilation in different operative positions of female patients under general anesthesia

Objective

This study aimed to compare the effectiveness and safety of different titrated methods used to determine individual positive end-expiratory pressure (PEEP) for intraoperative mechanical ventilation in female patients undergoing general anesthesia in different operative positions, and provide reference ranges of optimal PEEP values based on the titration.

Methods

A total of 123 female patients who underwent elective open abdominal surgery under general anesthesia were included in this study. After endotracheal intubation, patients' body position was adjusted to the supine position, Trendelenburg positions at 10° and 20° respectively. PEEP was titrated from 20 cmH2O to 4 cmH2O, decreasing by 2 cmH2O every 1 min. Electrical impedance tomography (EIT), hemodynamic and respiratory mechanics parameters were continuously monitored and recorded. Optimal PEEP values and reference ranges were respectively calculated based on optimal EIT parameters, mean arterial pressure (MAP), and lung dynamic compliance (Cdyn).

Results

EIT-guided optimal PEEP was found to have higher values than those of the MAP-guided and Cdyn-guided methods for all three body positions (P < 0.001), and it was observed to more significantly inhibit hemodynamics (P < 0.05). The variable coefficients of EIT-guided optimal PEEP values were smaller than those of the other two methods, and this technique could provide better ventilation uniformity for dorsal/ventral lung fields and better balance for pulmonary atelectasis/collapse. The 95% reference ranges of EIT-guided optimal PEEP values were 4.6-13.8 cmH2O, 7.0-15.0 cmH2O and 8.6-17.0 cmH2O for the supine position, Trendelenburg 10°, and Trendelenburg 20° positions, respectively.

Conclusion

EIT-guided optimal PEEP titration was found to be a superior method for lung protective ventilation in different operative positions under general anesthesia. The calculated reference ranges of PEEP values based on the EIT-guided method can be used as a reference for intraoperative mechanical ventilation.

Ventilation strategy during urological and gynaecological robotic-assisted surgery: a narrative review

Robotic-assisted surgery has improved the precision and accuracy of surgical movements with subsequent improved outcomes. However, it requires steep Trendelenburg positioning combined with pneumoperitoneum that negatively affects respiratory mechanics and increases the risk of postoperative respiratory complications. This narrative review summarises the state of the art in ventilatory management of these patients in terms of levels of positive end-expiratory pressure (PEEP), tidal volume, recruitment manoeuvres, and ventilation modes during both urological and gynaecological robotic-assisted surgery. A review of the literature was conducted using PubMed/MEDLINE; after completing abstract and full-text review, 31 articles were included. Although different levels of PEEP were often evaluated within a protective ventilation strategy, including higher levels of PEEP, lower tidal volume, and recruitment manoeuvres vs a conventional ventilation strategy, we conclude that the best PEEP in terms of lung mechanics, gas exchange, and ventilation distribution has not been defined, but moderate PEEP levels (4-8 cm H2O) could be associated with better outcomes than lower or highest levels. Recruitment manoeuvres improved intraoperative arterial oxygenation, end-expiratory lung volume and the distribution of ventilation to dependent (dorsal) lung regions. Pressure-controlled compared with volume-controlled ventilation showed lower peak airway pressures with both higher compliance and higher carbon dioxide clearance. We propose directions to optimise ventilatory management during robotic surgery in light of the current evidence.

Review of Risk Factors and Complications of Anterior Migration of Ozurdex Implant: Lessons Learnt from the Previous Reports

Purpose: Ozurdex had shown promising anatomical and functional outcomes in managing refractory Irvine-Gass syndrome over the years. Burgeoning usage of Ozurdex has prompted the study of its related complications, particularly the anterior chamber migration of the implant. Methods: Literature reviews on the anterior chamber migration of the Ozurdex via PubMed, EBSCO, and TRIP databases were searched from 2012 to 2020. The predisposing factors, outcomes, and management of such cases were evaluated. Results: A total of 54 articles consisting of 105 cases of anterior migration of Ozurdex were included in this analysis. The vitrectomized eye and compromised posterior capsule were highly associated with this complication. About 81.9% of the cases had cornea edema upon presentation, with 31.4% of them ending up with cornea decompensation despite intervention. Although there was high intraocular pressure reported initially in 22 cases, only 2 cases required glaucoma filtration surgeries in which they had preexisting glaucoma. Numerous techniques of repositioning or surgical removal of the implant were described but they were challenging and the outcomes varied. Conclusions: A noninvasive method of manipulating the Ozurdex into the vitreous cavity via the "Trendelenburg position, external pressure with head positioning" maneuvers is safe yet achieves a favorable outcome. Precaution must be taken whenever offering Ozurdex to the high-risk eyes. Prompt repositioning or removal of the implant is crucial to deter cornea decompensation. Clinical Trial Registration number: NMRR-22-02092-S9X (from the Medical Research and Ethics Committee (MREC), Ministry of Health, Malaysia).

Improving Trendelenburg position effectiveness by varying cardiopulmonary bypass flow

INTRODUCTION

Trendelenburg position (TP) is used to transport gaseous emboli away from the cerebral region during cardiac surgery. However, TP effectiveness has not been fully considered when combined with varying the cardiopulmonary bypass (CPB) flow. This study simulated the supine and TP at different pump flows and assessed the trapped emboli and embolic load entering the aortic arch branch arteries (AABA).

METHODS

A computational fluid dynamics (CFD) approach used a centrally cannulated adult patient-specific aorta model replicating a CPB circuit. Air emboli of 0.1 mm, 0.5 mm, and 1.0 mm (n = 700 each) were injected into the aorta placed in the supine position (0°) and the TP (-20°) at 2 L/min and 5 L/min. The number of emboli entering the AABA were compared. An aortic phantom flow experiment was performed to validate air bubble behaviour.

RESULTS

TP at 5 L/min had the lowest 0.1 mm mean (±SD) embolic load compared to the supine 2 L/min (55.3 ± 30.8 vs 64.3 ± 35.4). For both the supine and TP, the lower flow of 2 L/min had the highest number of simulated trapped emboli in higher elevated regions than at 5 L/min (541 ± 185 and 548 ± 191 vs 520 ± 159 and 512 ± 174), respectively. The flow experiment demonstrated that 2 L/min promoted bubble coalescence and high amounts of trapped emboli and 5 L/min transported air emboli away from the AABA.

CONCLUSIONS

TP effectiveness was improved by using CPB flow to manage air emboli. These results provide insights for predicting emboli behaviour and improving emboli de-airing procedures.

Perioperative lung function following flow controlled ventilation for robot-assisted prostatectomies in steep trendelenburg position: an observational study

BACKGROUND

Steep Trendelenburg position combined with capnoperitoneum can lead to pulmonary complications and prolonged affection of postoperative lung function. Changes in pulmonary function occur independent of different modes of ventilation and levels of positive end-expiratory pressure (PEEP). The effect of flow-controlled ventilation (FCV) has not been evaluated yet. We perioperatively measured spirometric lung function parameters in patients undergoing robot-assisted prostatectomy under FCV. Our primary hypothesis was that there is no significant difference in the ratio of the maximal mid expiratory and inspiratory flow (MEF50/MIF50) after surgery.

METHODS

In 20 patients, spirometric measurements were obtained preoperatively, 40, 120, and 240 min and 1 and 5 days postoperatively. We measured MEF50/MIF50, vital capacity (VC), forced expiratory volume in 1 s (FEV1), and intraoperative ventilation parameters.

RESULTS

MEF50/MIF50 ratio increased from 0.92 (CI 0.73-1.11) to 1.38 (CI 1.01-1.75, p < 0.0001) and returned to baseline within 24 h, while VC and FEV1 decreased postoperatively with a second nadir at 24 h and only normalized by the fifth day (p < 0.0001). Compared to patients with PCV, postoperative lung function changes similarly.

CONCLUSION

Flow-controlled ventilation led to changes in lung function similar to those observed with pressure-controlled ventilation. While the ratio of MEF50/MIF50 normalized within 24 h, VC and FEV1 recovered within 5 days after surgery.

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.

Guidelines in Practice: Positioning the Patient

Positioning the patient is an important perioperative task; the recently updated AORN "Guideline for positioning the patient" provides perioperative personnel with background information and evidence-based best practices for perioperative patient positioning and focuses on maintaining patient and staff member safety. The revised guideline includes recommendations for placing patients safely in a variety of positions and avoiding positioning injuries, such as postoperative vision loss. This article provides an overview of positioning recommendations for assessing patients' risk for injury, implementing safe positioning practices, placing patients in the Trendelenburg position, and preventing intraocular injuries. It also includes a patient-focused scenario on preventing adverse events associated with the Trendelenburg position that aligns with information discussed in the article. Perioperative nurses should review the guideline in its entirety and implement appropriate recommendations for positioning patients during procedures.

Haemodynamic and respiratory perioperative outcomes for open versus robot-assisted radical cystectomy: A double-blinded, randomised trial

BACKGROUND

The clinical impact of prolonged steep Trendelenburg position and CO₂ pneumoperitoneum during robot-assisted radical cystectomy (RC) on intraoperative conditions and immediate postoperative recovery remains to be assessed. The current study investigates intraoperative and immediate postoperative outcomes for open RC (ORC) versus robot-assisted RC with intracorporal urinary diversion (iRARC) in a blinded randomised trial. We hypothesised that ORC would result in a faster haemodynamic and respiratory post-anaesthesia care unit (PACU) recovery compared to iRARC.

METHODS

This study is a predefined sub-analysis of a single-centre, double-blinded, randomised feasibility study. Fifty bladder cancer patients were randomly assigned to ORC (n = 25) or iRARC (n = 25). Patients, PACU staff, and ward personnel were blinded to the surgical technique. Both randomisation arms followed the same anaesthesiologic procedure, fluid treatment plan, and PACU care. The primary outcome was immediate postoperative recovery using a standardised PACU Discharge Criteria (PACU-DC) score. Secondary outcomes included respiration- and arterial O₂ saturation scores as well as perioperative interventions and recordings.

RESULTS

All patients underwent the allocated treatment. The total PACU-DC score was highest 6 h postoperatively with no difference in the total score between randomisation arms (p = 0.80). Both the ORC and iRARC groups maintained a mean respiration- and arterial O₂ saturation score below 1 (out of 3) throughout PACU stay. The iRARC patients had significantly, but clinically acceptable, higher maximum airway pressure and arterial blood pressure, as well as lower minimum pH levels. The ORC group received significantly more opioids after extubation but marginally less analgesics in the PACU, compared to the iRARC group.

CONCLUSIONS

A prolonged Trendelenburg position and CO₂ pneumoperitoneum was well-tolerated during iRARC, and immediate postoperative recovery was similar for ORC and iRARC patients.

Changes in cerebral oxygen saturation with the Trendelenburg position and increased intraabdominal pressure in laparocopic rectal surgery

Objectives

Position changes and increased intra-abdominal pressure in laparoscopic interventions lead to some physiopathological changes. There is no definite information in the literature regarding cerebral oxygen saturation in patients undergoing colorectal surgery. Our aim was to investigate whether there is oxygen saturation change in the brain tissue in pneumoperitoneum and the Trendelenburg position during laparoscopic rectal surgery.

Material and Methods

Cerebral oxygen saturation was measured in 35 patients who underwent laparoscopic rectal surgery in the Trendelenburg position. Measurements were made under general anesthesia in the pneumoperitoneum and the Trendelenburg position.

Results

The values that are statistically affected by the position are systolic blood pressure, mean arterial blood pressure and cerebral oxygen saturation. The Trendelenburg position does not disturb the cerebral oxygen saturation and it causes an increase in saturation. After pneumoperitoneum occurred, changes in systolic blood pressure, mean arterial blood pressure and brain oxygen saturation were detected. Cerebral oxygen saturation increases with the formation of pneumoperitoneum.

Conclusion

The Trendelenburg position and increased intraabdominal pressure during laparoscopic rectal surgery do not impair brain oxygen saturation.

Efficacy of the three-point cuff palpation technique in preventing endobronchial tube migration during positioning in robotic pelvic surgeries

Background and Aims

During robotic pelvic surgeries, the shortening of endotracheal tube (ETT) tip-to-carina distance (D_TC) during pneumoperitoneum with 45° Trendelenburg position can result in endobronchial tube migration. In the three-point ETT cuff palpation (TPP) technique, maximal ETT cuff distension is felt over the tracheal segment located between the cricoid-thyroid membrane and suprasternal notch, which is likely to provide optimal placement. However, the reproducibility and reliability of the TPP technique in preventing endobronchial tube migration are yet to be evaluated. Hence, we compared three ETT placement techniques: TPP technique, intubation guide mark (IGM) technique and Varshney's formula (VF) for the prevention of endobronchial tube migration during robotic pelvic surgeries.

Methods

ETT placement by TPP was compared with IGM and VF techniques in 100 American Society of Anesthesiologists physical class II-III patients, by assessing the serial changes in D_TC and incidence of endobronchial tube migration throughout the different phases of pneumoperitoneum and Trendelenburg position using t-test and Chi-square test. Changes in the D_TC during various phases were also measured.

Results

D_TC (mean ± standard deviation) at baseline and during pneumoperitoneum was significantly better in TPP technique (2.80 ± 0.62 cm and 1.96 ± 0.66 cm) as compared to both IGM (2.50 ± 1.27 cm and 1.41 ± 1.29 cm) and VF techniques (1.83 ± 1.13 cm and 0.98 ± 1.18 cm), P < 0.001. During pneumoperitoneum, the mean shortening of D_TC was 0.84 ± 0.20 cm, and no endobronchial tube migration was found in TPP technique compared to 20% in IGM and 25% in VF techniques, P < 0.001.

Conclusion

TPP is a simple and reliable technique, which provides optimal ETT placement and prevents endobronchial tube migration throughout the different phases of robotic pelvic surgeries.

Effect of dexmedetomidine on intracranial pressure in patients undergoing gynecological laparoscopic surgery in Trendelenburg position through ultrasonographic measurement of optic nerve sheath diameter

OBJECTIVE

To evaluate the effect of dexmedetomidine on intracranial pressure (ICP) in patients undergoing gynecological laparoscopic surgery in Trendelenburg position through ultrasonographic measurement of optic nerve sheath diameter (ONSD).

METHODS

Ninety patients underwent total laparoscopic hysterectomy were selected as research subjects in this prospective study. These patients were divided into a dexmedetomidine group (n=45) and a control group (n=45) using a random number table. The dexmedetomidine group was pumped with 0.5 μg/kg dexmedetomidine (20041731, Yangtze River Pharmaceutical Group, China) 10 min before the anesthesia induction, followed by a continuous pump of 0.5 μg/(kg·h) until the end of the surgery, and the control group was pumped with 0.5 μg/(kg·h) 0.9% sodium chloride solution. Patients in both groups were assisted with mechanical ventilator after endotracheal intubation by rapid induction. Intraoperatively, the pneumoperitoneum pressure was maintained at 14 mmHg, and the bispectral index was maintained at 40 to 60. We recorded ONSD measured with ultrasonography in both groups at 5 min before induction of anesthesia in supine position (T1), 5 min after CO₂ pneumoperitoneum in Trendelenburg position (T2), 30 min after CO₂ pneumoperitoneum in Trendelenburg position (T3), 60 min after CO₂ pneumoperitoneum in Trendelenburg position (T4) and 5 min after the close of pneumoperitoneum in supine position (T5). The cerebral oxygen metabolism indicators of the two groups at different time periods were compared, including jugular venous oxygen saturation (SjvO₂), arterial content and arterial-to-internal jugular difference (Da-jvO₂), cerebral oxygen extraction rate (CERO₂). Heart rate (HR) and mean arterial pressure (MAP) were also recorded at T1-T5. Besides, American Society of Anesthesiologists (ASA) grade, time of endotracheal extubation, recovery time for orientation and postoperative adverse reactions were recorded in each group.

RESULTS

There were significant differences in ONSD at T2 ((4.77±0.14) mm vs. (4.98±0.13) mm), T3 ((5.19±0.15) mm vs. (5.53±0.14) mm), T4 ((5.10±0.11) mm vs. (5.27±0.13) mm) and T5 ((4.71±0.12) mm vs. (4.4±0.16) mm) between the two groups (all P<0.05), and obvious differences were also found within groups when comparing the ONSD at T2-T5 to that at T1 (P<0.05). There were also significant differences in SjvO₂, Da-jvO₂ and CERO₂ between the control group and the dexmedetomidine group at T2-T5 (all P<0.05), and obvious differences were found within groups when comparing the indices at T2-T5 to those at T1 (P<0.05). The incidences of postoperative dizziness (20.00%), nausea and vomiting (17.78%), and headache (13.33%) in the dexmedetomidine group and were significantly lower than those in the control group (55.56%, 48.89% and 42.22%, respectively; all P<0.05). At T2-T5, dexmedetomidine group had lower HR than control group (P<0.05), while no differences were found in MAP between the two groups (P>0.05). There were also no differences in ASA grade, time of endotracheal extubation, and recovery time for orientation between the two groups (both P>0.05).

CONCLUSION

Dexmedetomidine can effectively decrease the occurence of increased ICP in patients undergoing gynecological laparoscopic surgery in Trendelenburg position, improve brain oxygen metabolism, and reduce the incidences of postoperative dizziness, nausea and vomiting as well as headache (China Clinical Trials Registration Center, registration number: ChiCTR2100052046, https://www.chictr.org.cn).

Recruitable alveolar collapse and overdistension during laparoscopic gynecological surgery and mechanical ventilation: a prospective clinical study

Background

Laparoscopic surgery in Trendelenburg position may impede mechanical ventilation (MV) due to positioning and high intra-abdominal pressure. We sought to identify the positive end-expiratory pressure (PEEP) levels necessary to counteract atelectasis formation (“Open-Lung-PEEP”) and to provide an equal balance between overdistension and alveolar collapse (“Best-Compromise-PEEP”).

Methods

In 30 patients undergoing laparoscopic gynecological surgery, relative overdistension and alveolar collapse were assessed with electrical impedance tomography (EIT) during a decremental PEEP trial ranging from 20 to 4 cmH₂O in supine position without capnoperitoneum and in Trendelenburg position with capnoperitoneum.

Results

In supine position, the median Open-Lung-PEEP was 12 (8–14) cmH₂O with 8.7 (4.7–15.5)% of overdistension and 1.7 (0.4–2.2)% of collapse. Best-Compromise-PEEP was 8 (6.5–10) cmH₂O with 4.2 (2.4–7.2)% of overdistension and 5.1 (3.9–6.5)% of collapse. In Trendelenburg position with capnoperitoneum, Open-Lung-PEEP was 18 (18–20) cmH ₂ O (p < 0.0001 vs supine position) with 1.8 (0.5–3.9)% of overdistension and 0 (0–1.2)% of collapse and Best-Compromise-PEEP was 18 (16–20) cmH₂O (p < 0.0001 vs supine position) with 1.5 (0.7–3.0)% of overdistension and 0.2 (0–2.7)% of collapse. Open-Lung-PEEP and Best-Compromise-PEEP were positively correlated with body mass index during MV in supine position but not in Trendelenburg position.

Conclusion

The PEEP levels required for preventing alveolar collapse and for balancing collapse and overdistension in Trendelenburg position with capnoperitoneum were significantly higher than those required for achieving the same goals in supine position without capnoperitoneum. Even with high PEEP levels, alveolar overdistension was negligible during MV in Trendelenburg position with capnoperitoneum.

Trial registration

This study was prospectively registered at German Clinical Trials registry (DRKS00016974).

Inflatable penile prosthesis reservoir placement-Are we ready for a paradigm change?

In 2002, Steve Wilson pioneered new procedures for alternative placement of reservoirs for inflatable prostheses in patients who have suffered damage to the space of Retzius following pelvic surgery or obliteration of the transversalis fascia by mesh hernia repair. Since then, surgical techniques and tools for ectopic reservoir placement have gradually gained acceptance to minimize palpability, and the risk of visceral and vascular lesions for high risk patients has been all but eliminated. Lockout valves and high submuscular placement techniques are now recommended, and reports of vascular, bowel or bladder injuries are uncommonly rare. While surgeons continue their search for safer and more effective placement methods, new skills and instruments are constantly being introduced to make recommendations to minimize complications and provide safety and functionality. Additional studies and comparisons of techniques are needed to achieve a consensus of best practice for reservoir placement solutions.

Effect of pneumoperitoneum and Trendelenburg position on internal carotid artery blood flow measured by ultrasound during robotic prostatectomy

INTRODUCTION

Robotic prostatectomy requires pneumoperitoneum and a steep Trendelenburg position; however, this condition may compromise cerebral blood flow. Here, we evaluated the effect of pneumoperitoneum and the steep Trendelenburg position on internal carotid artery (ICA) blood flow measured by Doppler ultrasound during robotic prostatectomy.

METHODS

Patients who underwent robotic prostatectomy were prospectively recruited. The ICA blood flow was measured at the following five time-points: with the patient awake and in the supine position (Ta), 10 min after anaesthetic induction in the supine position (T1), 10 (T2) and 30 (T3) min after pneumoperitoneum in the steep Trendelenburg position, and at the end of surgery in the supine position after desufflation of the pneumoperitoneum (T4). Hemodynamic and cerebrovascular variables were measured at each time-point.

RESULTS

A total of 28 patients were evaluated. The ICA blood flows were significantly lower at T2 and T3 than at T1 (162.3±44.7 [T2] vs. 188.0±49.6 mL/min [T1], P=0.002; 163.1±39.9 [T3] vs. 188.0±49.6 mL/min [T1], P=0.009). The ICA blood flow also differed significantly between Ta and T1 (236.8±58.3 vs. 188.0±49.6 mL/min, P<0.001). Heart rates, cardiac indexes, peak systolic velocity, and end-diastolic velocity were significantly lower at T2 and T3 than at T1. However, ICA diameter, mean blood pressure, and end-tidal carbon dioxide partial pressure did not differ significantly at all time-points.

CONCLUSION

Pneumoperitoneum and the steep Trendelenburg position caused decreased ICA blood flow, suggesting that they should be carefully performed during robotic prostatectomy, especially in patients at risk of postoperative cerebrovascular accident. This article is protected by copyright. All rights reserved.

Influence of steep Trendelenburg position on postoperative complications: a systematic review and meta-analysis

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.

Effects of propofol and inhalational anesthetics on the optic nerve sheath diameter in patients undergoing surgery in the steep Trendelenburg position: a systematic review and meta-analysis

BACKGROUND

Optic nerve sheath diameter (ONSD) is recognized as a surrogate indicator of intracranial pressure (ICP) during surgery. Due to the requirements of surgery, the adjustment to the steep Trendelenburg position and the establishment of CO2 pneumoperitoneum can lead to an increase in ICP, resulting in an increase in the ONSD. Anesthetic agents have different impacts on cerebral blood volume and ICP. The aim of this study was to evaluate the effects of propofol and inhalational anesthetics on the ONSD based on data from randomized controlled trials (RCTs).

METHODS

The electronic databases of PubMed, EMBASE, Ovid MEDLINE, the Cochrane Library, and other databases were searched systematically using specified keywords from their inception to June 2021. The Chi-square test and I2 test were used to evaluate the heterogeneity across the studies. The weighted mean difference (WMD) with 95% confidence interval (CI) were adopted to analyze continuous data.

RESULTS

A total of 379 patients from 7 studies were involved in this meta-analysis. There were borderline significant differences in the ONSD atT2 between propofol and the control group: T2 (WMD =-0.15, 95% CI: -0.31, -0.00, P=0.005). There were significant differences at T3 (WMD =-0.23,95% CI: -0.42, -0.05, P =0.013) and T4 (WMD  =-0.18, 95% CI: -0.29, -0.07, P =0 .001). After statistical verification, there was no significant difference in the ONSD at T1 between the 2 groups: T1 (WMD =-0.08, 95% CI: -0.26, 0.10, P =0 .368). There were also no significant differences in mean arterial pressure (MAP) (P=0.654, 0.445, 0.698, and 0.562, respectively) and end tidal CO2 (ETCO2) (P=0.081, 0.506, 0.126, and 0.983, respectively) at T1, T2, T3 and T4 between propofol and inhalational anesthetics.

DISCUSSION

The findings in the present study indicated that the ONSD during propofol anesthesia was significantly lower than that during inhalational anesthesia after adopting the Trendelenburg position and CO2 pneumoperitoneum. These analysis results suggest that propofol anesthesia may help to minimize changes in ICP compared to inhalational anesthetics.

Evaluation of hemodynamic changes during laparoscopic cholecystectomy by transthoracic echocardiography

Background and Aims:

The purpose of this study was to prospectively examine the effects of pneumoperitoneum and the reverse Trendelenburg position on cardiac hemodynamics during laparoscopic cholecystectomy using transthoracic echocardiography (TTE).

Material and Methods:

In this prospective observational study, after institutional review board clearance, forty patients of either sex of ASA I-II status undergoing laparoscopic cholecystectomy were enrolled in the study. Changes in cardiac output, stroke volume, and ejection fraction were recorded using TTE at different time intervals: Preoperatively, before creation of pneumoperitoneum, 5 min after creation of pneumoperitoneum, and 5 min after setting the operative reverse Trendelenburg position with legs at the level of the hips. All statistical analyses were performed using the statistical program SPSS version 16 and P value less than 0.05 was considered as statistically significant. Data were examined using mixed analysis of variance (ANOVA) followed by post hoc Bonferroni correction.

Results:

There was significant fall in cardiac output (CO) (45%, P < 0.001), stroke volume (SV) (42%, P < 0.001), and ejection fraction (EF) (31.8% change, P < 0.001) after creation of pneumoperitoneum with significant rise in MAP (11%, P < 0.001). But with reverse Trendelenburg position, there was a significant improvement of CO (30%), SV (28%), and EF (21% change) in comparison to values after pneumoperitoneum, but still remained below baseline. There was no change in heart rate at different time intervals. There was no significant difference in hemodynamics between ASA I and II patients.

Conclusion:

Patients undergoing laparoscopic cholecystectomy undergo significant hemodynamic changes after pneumoperitoneum and reverse Trendelenburg position.

Comparison of the Effects of Normocapnia and Mild Hypercapnia on the Optic Nerve Sheath Diameter and Regional Cerebral Oxygen Saturation in Patients Undergoing Gynecological Laparoscopy with Total Intravenous Anesthesia

Cerebral hemodynamics may be altered by hypercapnia during a lung-protective ventilation (LPV), CO₂ pneumoperitoneum, and Trendelenburg position during general anesthesia. The purpose of this study was to compare the effects of normocapnia and mild hypercapnia on the optic nerve sheath diameter (ONSD), regional cerebral oxygen saturation (rSO₂), and intraoperative respiratory mechanics in patients undergoing gynecological laparoscopy under total intravenous anesthesia (TIVA). Sixty patients (aged between 19 and 65 years) scheduled for laparoscopic gynecological surgery in the Trendelenburg position. Patients under propofol/remifentanil total intravenous anesthesia were randomly assigned to either the normocapnia group (target PaCO₂ = 35 mmHg, n = 30) or the hypercapnia group (target PaCO₂ = 50 mmHg, n = 30). The ONSD, rSO₂, and respiratory and hemodynamic parameters were measured at 5 min after anesthetic induction (Tind) in the supine position, and at 10 min and 40 min after pneumoperitoneum (Tpp10 and Tpp40, respectively) in the Trendelenburg position. There was no significant intergroup difference in change over time in the ONSD (p = 0.318). The ONSD increased significantly at Tpp40 when compared to Tind in both normocapnia and hypercapnia groups (p = 0.02 and 0.002, respectively). There was a significant intergroup difference in changes over time in the rSO2 (p < 0.001). The rSO₂ decreased significantly in the normocapnia group (p = 0.01), whereas it increased significantly in the hypercapnia group at Tpp40 compared with Tind (p = 0.002). Alveolar dead space was significantly higher in the normocapnia group than in the hypercapnia group at Tpp40 (p = 0.001). In conclusion, mild hypercapnia during the LPV might not aggravate the increase in the ONSD during CO₂ pneumoperitoneum in the Trendelenburg position and could improve rSO₂ compared to normocapnia in patients undergoing gynecological laparoscopy with TIVA.

Umbilical cord prolapse: revisiting its definition and management

Umbilical cord prolapse is an unpredictable obstetrical emergency with an incidence ranging from 1 to 6 per 1000 pregnancies. It is associated with high perinatal mortality, ranging from 23% to 27% in low-income countries to 6% to 10% in high-income countries. In this review, we specifically addressed 3 issues. First, its definition is not consistent in the current literature, and "occult cord prolapse" is a misnomer because the cord is still above the cervix. We proposed that cord prolapse, cord presentation, and compound cord presentation should be classified according to the positional relationship among the cord, the fetal presenting part, and the cervix. All of them may occur with either ruptured or intact membranes. The fetal risk is highest in cord prolapse, followed by cord presentation, and lastly by compound cord presentation, which replaces the misnomer "occult cord prolapse." Second, the mainstay of treatment of cord prolapse is urgent delivery, which means cesarean delivery in most cases, unless vaginal delivery is imminent. The urgency depends on the fetal heart rate pattern, which can be bradycardia, recurrent decelerations, or normal. It is most urgent in cases with bradycardia, because a recent study showed that cord arterial pH declines significantly with the bradycardia-to-delivery interval at a rate of 0.009 per minute (95% confident interval, 0.0003-0.0180), and this may indicate an irreversible pathology such as vasospasm or persistent cord compression. However, cord arterial pH does not correlate with either deceleration-to-delivery interval or decision-to-delivery interval, indicating that intermittent cord compression causing decelerations is reversible and less risk. Third, while cesarean delivery is being arranged, different maneuvers should be adopted to relieve cord compression by elevating the fetal presenting part and to prevent further cord prolapse beyond the vagina. A recent study showed that the knee-chest position provides the greatest elevation effect, followed by filling of the maternal urinary bladder with 500 mL of fluid, and then the Trendelenburg position (15°) and other maneuvers. However, each maneuver has its own advantages and limitations; thus, they should be applied wisely and with great caution, depending on the actual clinical situation. Therefore, we have proposed an algorithm to guide this acute management.

Transperineal ultrasound assessment of fetal head elevation by maneuvers used for managing umbilical cord prolapse

OBJECTIVE

To assess objectively the degree of fetal head elevation achieved by different maneuvers commonly used for managing umbilical cord prolapse.

METHODS

This was a prospective observational study of pregnant women at term before elective Cesarean delivery. A baseline assessment of fetal head station was performed with the woman in the supine position, using transperineal ultrasound for measuring the parasagittal angle of progression (psAOP), head-symphysis distance (HSD) and head-perineum distance (HPD). The ultrasonographic measurements of fetal head station were repeated during different maneuvers, including elevation of the maternal buttocks using a wedge, knee-chest position, Trendelenburg position with a 15° tilt and filling the maternal urinary bladder with 100 mL, 300 mL and 500 mL of normal saline. The measurements obtained during the maneuvers were compared with the baseline measurements.

RESULTS

Twenty pregnant women scheduled for elective Cesarean section at term were included in the study. When compared with baseline (median psAOP, 103.6°), the knee-chest position gave the strongest elevation effect, with the greatest reduction in psAOP (psAOP, 80.7°; P < 0.001), followed by filling the bladder with 500 mL (psAOP, 89.9°; P < 0.001) and 300 mL (psAOP, 94.4°; P < 0.001) of normal saline. Filling the maternal bladder with 100 mL of normal saline (psAOP, 96.1°; P = 0.001), the Trendelenburg position (psAOP, 96.8°; P = 0.014) and elevating the maternal buttocks (psAOP, 98.3°; P = 0.033) gave modest elevation effects. Similar findings were reported for HSD and HPD. The fetal head elevation effects of the knee-chest position, Trendelenburg position and elevation of the maternal buttocks were independent of the initial fetal head station, but that of bladder filling was greater when the initial head station was low.

CONCLUSIONS

To elevate the fetal presenting part, the knee-chest position provides the best effect, followed by filling the maternal urinary bladder with 500 mL then 300 mL of fluid, respectively. Filling the bladder with 100 mL of fluid, the Trendelenburg position and elevation of the maternal buttocks have modest effects. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

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

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

Clinical Trial registry: chictr.org. identifier: ChiCTR-2100044928

Surgery in antiquity: the origin of the Trendelenburg position revisited

INTRODUCTION

The Raised Pelvic Position, also known as Trendelenburg position, consists of the elevation of the pelvis above the horizontal plane in the supine position with the head lowered. The position is named after Friedrich Trendelenburg, a German surgeon, who flourished in Berlin at the end of the nineteenth century. Although modern studies trace the position's principle back to the first century BC, we herein present even earlier descriptions, dating back to the fifth century BC.

MATERIAL AND METHODS

The whole ancient Greek literature was digitally searched. All relevant references were analyzed from the original sources.

RESULTS

We found at least nine references to the Raised Pelvic Position in the ancient Greek literature from the following physicians: Hippocrates (fifth century BC), Soranus of Ephesus (first century AD), Aetius of Amida (fifth century AD) and Paulus Aegineta (seventh century AD).

DISCUSSION AND CONCLUSION

All references presented, describe clearly the Raised Pelvic Position, as part of a strategy to repair uterine pathologies, mainly prolapsed uterus, but also instability, bleeding, tumors and infertility. We conclude that ancient Greek writers were aware of the usefulness of the head-down position, as reflected from the numerous existing descriptions dating back to the fifth century BC.

Comparison of the effects of normal and low blood pressure regulation on the optic nerve sheath diameter in robot assisted laparoscopic radical prostatectomy

Background

Robot-assisted laparoscopic radical prostatectomy is an advanced and popular surgical technique. However, increased intracranial pressure which is caused by CO₂ pneumoperitoneum and Trendelenburg position is the main cerebrovascular effect. Measurement of optic nerve sheath diameter using ocular ultrasound is a noninvasive and reliable method for the assessment of intracranial pressure. The primary endpoint of this study was to identify whether low blood pressure regulation has any benefit in attenuating an increase of optic nerve sheath diameter during robot-assisted laparoscopic radical prostatectomy.

Methods

Optic nerve sheath diameter and cerebral oxygen saturation were measured at baseline (supine position), one and two hours after pneumoperitoneum and Trendelenburg position respectively, and after return to supine position in normal (n = 27) and low blood pressure groups (n = 24).

Results

Mean optic nerve sheath diameter values measured at one and two hours after pneumoperitoneum and Trendelenburg position were significantly increased compared to the baseline value (P < 0.001 in normal blood pressure group; P = 0.003 in low blood pressure group). However, the mean optic nerve sheath diameter and cerebral oxygen saturation measured at any of the time points as well as degrees of change between the two groups did not show any significant changes. The peak values of optic nerve sheath diameter in normal and low blood pressure groups demonstrated 14.9% and 9.2% increases, respectively.

Conclusions

Low blood pressure group demonstrated an effect in maintaining an increase of optic nerve sheath diameter less than 10% during CO₂ pneumoperitoneum and Trendelenburg position.

Intraocular pressure during robotic-assisted laparoscopic prostatectomy: a prospective observational study

Background and objectives

Although previous reports have shown intraocular pressure changes during robotic-assisted laparoscopic prostatectomy, they did not discuss the time course of changes or the timing of the largest change. We conducted this study to quantify pressure changes over time in patients assuming the steep Trendelenburg position during robotic-assisted laparoscopic prostatectomy.

Methods

Twenty-one men were enrolled. Intraocular pressure was measured before anesthesia induction in the supine position (T0); 30 (T1), 90 (T2), and 150 minutes after assuming the Trendelenburg position (T3); and 30 minutes after reassuming the supine position (T4). End-tidal carbon dioxide and blood pressure were also recorded. To compare intraocular pressure between the time points, we performed repeated-measures analysis of variance. A mixed-effects multivariate regression analysis was conducted to adjust for confounding factors.

Results

The mean (standard deviation) intraocular pressure was 18.3 (2.4), 23.6 (3.0), 25.1 (3.1), 25.3 (2.2), and 18.1 (5.0) mmHg at T0, T1, T2, T3, and T4, respectively. The mean intraocular pressure was higher at T1, T2, and T3 than at T0 (p < 0.0001 for all). There was no significant difference between T0 and T4, and between T3 and T2 (p > 0.99 for both).

Conclusions

The Trendelenburg position during robotic-assisted laparoscopic prostatectomy increased intraocular pressure. The increase was moderate at 90 minutes after the position was assumed, with the value being approximately 7 mmHg higher than the baseline value. The baseline intraocular pressure was restored at 30 minutes after the supine position was reassumed.

Trial registration

UMIN ID 000014973

Date of registration

August 27, 2014

The effect of robotic surgery on intraocular pressure and optic nerve sheath diameter: a prospective study

Background and objectives

To investigate the effect of the steep Trendelenburg position (35° to 45°) and carbon dioxide (CO2) insufflation on optic nerve sheath diameter (ONSD), intraocular pressure (IOP), and hemodynamic parameters in patients undergoing robot-assisted laparoscopic prostatectomy (RALP), and to evaluate possible correlations between these parameters.

Methods

A total of 34 patients were included in this study. ONSD was measured using ultrasonography and IOP was measured using a tonometer at four time points: T1 (5 minutes after intubation in the supine position); T2 (30 minutes after CO2 insufflation); T3 (120 minutes in steep Trendelenburg position); and T4 (in the supine position, after abdominal exsufflation). Systolic and diastolic arterial pressure, heart rate, and end-tidal CO2 (etCO2) were also evaluated.

Results

The mean IOP was 12.4 mmHg at T1, 20 mmHg at T2, 21.8 mmHg at T3, and 15.6 mmHg at T4. The mean ONSD was 4.87 mm at T1, 5.21 mm at T2, 5.30 mm at T3, and 5.08 at T4. There was a statistically significant increase and decrease in IOP and ONSD between measurements at T1 and T4, respectively. However, no significant correlation was found between IOP and ONSD. A significant positive correlation was found only between ONSD and diastolic arterial pressure. Mean arterial pressure, heart rate, and etCO2 were not correlated with IOP or ONSD.

Conclusions

A significant increase in IOP and ONSD were evident during RALP; however, there was no significant correlation between the two parameters.

Effects of sevoflurane and propofol on the optic nerve sheath diameter in patients undergoing laparoscopic gynecological surgery: a randomized controlled clinical studies

Background

The results of studies on changes in intracranial pressure in patients undergoing laparoscopic surgery are inconsistent. Meanwhile, previous neurosurgery studies have suggested that propofol and sevoflurane have inconsistent effects on cerebral blood flow and cerebrovascular self-regulation. The purpose of this study is to compare changes in the optic nerve sheath diameter in patients undergoing laparoscopic gynecological surgery under anesthetic maintenance with propofol versus sevoflurane.

Methods

This study included 110 patients undergoing laparoscopic gynecological surgery with an estimated operative time of more than 2 h under general anesthesia. The study was a randomized controlled study. The optic nerve sheath diameter (ONSD) at various time points was measured by ultrasound, including when the patients entered the operating room (Tawake), after successful anesthesia induction and endotracheal intubation (Tinduction), when the body position was adjusted to the Trendelenburg position and the CO₂ pneumoperitoneum pressure reached 14 mmHg, which was recorded as T₀. Then, measurements were conducted every 15 min for the first 1 h and then once every hour until the end of the surgery (T₁₅, T₃₀, T₄₅, T_1h, T_2h …), after the end of surgery and the tracheal tube was removed (T_end), and before the patients were transferred to the ward (T_pacu).

Results

A significant difference in optic nerve sheath diameter was found between two groups at T₁₅, T₃₀, T₄₅ (4.64 ± 0.48 mm and 4.50 ± 0.29 mm, respectively, p = 0.031;4.77 ± 0.45 mm and 4.62 ± 0.28 mm, respectively, p = 0.036;4.84 ± 0.46 mm and 4.65 ± 0.30 mm, respectively, p = 0.012), while there was no significant difference at T_awake and other time points.

Conclusion

During laparoscopic gynecological surgery lasting more than 2 h, the optic nerve sheath diameter was slightly larger in the propofol group than that in the sevoflurane group in the first 45 min. No significant difference was observed between the two groups 1 h after surgery.

Trial registration

clinicaltrials.gov, NCT03498235. Retrospectively registered 1 March 2018.

The manuscript adheres to CONSORT guidelines.

Risk of Upper-body Adverse Events in Robot-assisted Total Laparoscopic Hysterectomy for Benign Gynecologic Disease

STUDY OBJECTIVE

Recent studies suggest that prolonged Trendelenburg positioning during robot-assisted total laparoscopic hysterectomy (RA-TLH) may lead to fluid shifts and pulmonary, airway, head and neck, and cranial complications in the upper body. This study examined the upper-body complications during RA-TLH for benign gynecologic disease.

DESIGN

Population-based retrospective study.

SETTING

The National Inpatient Sample.

PATIENTS

A total of 771 412 women who had total hysterectomy for benign gynecologic disease from October 2008 to September 2015, including 661 284 women who had total abdominal hysterectomy (TAH), 51 544 women who had traditional TLH, and 58 584 women who had RA-TLH.

INTERVENTIONS

A multiple-group generalized boosted model to balance the measured baseline covariates across the 3 hysterectomy groups and a generalized estimating equation model to assess the effect size of complication risk (overall and upper-body complications).

MEASUREMENTS AND MAIN RESULTS

Women in the RA-TLH group were more likely to be older, white, and have a higher comorbidity index (all, p <.001). The overall rate of upper-body complications was 4.6% across the 3 groups. RA-TLH was not associated with increased risk of upper-body complications compared with traditional TLH (odds ratio [OR] 1.06; 95% confidence interval [CI], 0.90-1.26) or TAH (OR 0.98; 95% CI, 0.87-1.11). In contrast, RA-TLH was associated with decreased risk of overall perioperative complications compared with TAH (12.0% vs 18.6%; OR 0.64; 95% CI, 0.59-0.70; p <.001). RA-TLH and traditional TLH had similar risk of overall perioperative complications (12.0% vs 13.1%; OR 0.91; 95% CI, 0.8-1.02; p = .099). Women who developed upper-body complications had a higher perioperative mortality rate (0.4% vs <0.01%; OR 79.1; 95% CI, 36.0-174). The highest rates of complications (62.5%) were observed in morbidly obese women aged 70-79 with a comorbidity index of ≥4.

CONCLUSION

In hysterectomy for benign gynecologic disease, RA-TLH was not associated with an increased risk of upper-body complications compared with TAH or traditional TLH. However, older age and higher comorbidity are key risk factors that increase the risk of upper-body complications which carry a disproportionally high mortality rate.

Attenuation of the increase in intraocular pressure with dexmedetomidine: Systematic review with meta-analysis and trial sequential analysis

STUDY OBJECTIVE

Whether dexmedetomidine effectively attenuates the increase in intraocular pressure (IOP) remains inconclusive. We aim to evaluate the effects of dexmedetomidine on IOP in adult patients undergoing surgery which requires general anesthesia and endotracheal intubation.

DESIGN

Systematic review and meta-analysis.

INTERVENTIONS

Intravenous administration of dexmedetomidine during surgery.

MEASUREMENTS

Intraocular pressure.

METHODS

We searched PubMed, Embase, Scopus, Web of Science, Cochrane Library, Google Scholar, Wanfang Data, and China National Knowledge Infrastructure from the inception through April 14, 2020. Randomized control trials which involved adult patients undergoing surgery that required general anesthesia and endotracheal intubation, which compared intravenous administration of dexmedetomidine with placebo regarding the IOP levels, which also provided sufficient information for meta-analysis were considered eligible.

MAIN RESULTS

Twenty-nine randomized control trials were included. The IOP levels are significantly lower in patients receiving dexmedetomidine after the administration of dexmedetomidine [mean difference (MD), -2.04 mmHg; 95% confidence interval (CI), -2.40 mmHg to -1.67 mmHg], after the injection of succinylcholine (MD, -3.84 mmHg; 95% CI, -4.80 mmHg to -2.88 mmHg), after endotracheal intubation (MD, -3.64 mmHg; 95% CI, -4.46 mmHg to -2.82 mmHg), after pneumoperitoneum (MD, -3.12 mmHg; 95% CI, -3.93 mmHg to -2.30 mmHg), and after the patients being placed in a steep Trendelenburg position (MD, -4.12 mmHg; 95% CI, -5.39 mmHg to -2.85 mmHg). Trial sequential analyses for these outcomes are conclusive.

CONCLUSIONS

Dexmedetomidine effectively attenuates the increase in IOP levels, and should be considered especially for at-risk patients.

Effect of pneumoperitoneum on dynamic variables of fluid responsiveness (Delta PP and PVI) during Trendelenburg position

Background and Aims:

Pulse pressure variation (ΔPP) is considered as one of the best predictors of fluid responsiveness in patients under mechanical ventilation. Pleth Variability Index (PVI) has been proposed as a noninvasive alternative. However, pneumoperitoneum has been recently suggested as a limitation to their interpretation. The aim of this study was to compare changes in ΔPP and PVI related to autotransfusion associated with a Trendelenburg maneuver before and during pneumoperitoneum.

Methods:

50 patients undergoing elective abdominal laparoscopic surgery were enrolled in this prospective observational study. All patients were equipped with an invasive radial artery catheter and a PVI probe. After obtaining a stable signal with both ΔPP and PVI, baseline values were recorded, before and after head-down tilts of 10°, with or without abdominal insufflation (10-12 mmHg). All measurements were made before any fluid challenge under standardized anaesthesia, while patients were paralyzed and mechanically ventilated with 8 mL/kg tidal volume.

Results:

Changes in ΔPP and PVI associated with the Trendelenburg maneuver before and after insufflation of the pneumoperitoneum were significantly different (P < 0.001). In baseline conditions, the Trendelenburg maneuver was associated with a significant decrease in heart rate while mean arterial pressure remained unchanged. Both ΔPP and PVI decreased. After insufflation of the pneumoperitoneum, the Trendelenburg maneuver was associated with a significant decrease in heart rate and ΔPP and an increase in mean arterial pressure while PVI remained unchanged.

Conclusion:

Pneumoperitoneum did not alter the response of ΔPP to autotransfusion associated with the Trendelenburg maneuver, which was not the case for the PVI. This latter decreased during Trendelenburg maneuver performed alone and remained unchanged during Trendelenburg maneuver performed after insufflation of the pneumoperitoneum.

Postanesthesia care unit delirium following robot-assisted vs open retropubic radical prostatectomy: A prospective observational study

BACKGROUND

The aim of this study was to compare the incidence of early postoperative delirium in the postanesthesia care unit (PACU) between robot-assisted radical prostatectomy (RARP) in the extreme Trendelenburg position and open retropubic radical prostatectomy (ORP) in supine position.

METHODS

Patients were screened for delirium signs 15, 30, 45, and 60 minutes following extubation.

RESULTS

PACU delirium was present in 39.3% of RARP (64/163) patients and 41.8% of ORP (77/184) patients. Higher age (OR 1.072, 95%CI: 1.034-1.111, P < .001), total intravenous anesthesia (OR 2.001, 95%CI: 1.243-3.221, P = .004), and anesthesia duration (OR 1.255, 95%CI: 1.067-1.476, P = .006) were associated with PACU delirium, but no association was found between surgical technique and PACU delirium.

CONCLUSION

Compared with inhalational anesthesia, total intravenous anesthesia using propofol-sufentanil, higher age, and longer duration of anesthesia were associated with PACU delirium. Based on these findings, adverse effects on postoperative recovery and delirium signs do not have to be considered in the choice of surgical approach for radical prostatectomy.

TRIAL REGISTRATION

https://www.drks.de/, identifier: DRKS00010014.

Effect of postoperative Trendelenburg position on shoulder pain after gynecological laparoscopic procedures: a randomized clinical trial

BACKGROUND

Laparoscopic surgery has become a standard of care for many gynecological surgeries due to its lower morbidity, pain and cost compared to open techniques. Unfortunately, the use of carbon dioxide (CO2) to insufflate the abdomen is the main contributor to post-operative shoulder pain.

METHODS

We aim to assess the effect of postoperative Trendelenburg position on shoulder pain after gynecological laparoscopic procedures. We hypothesize that maintaining the patient in Trendelenburg for 24 h postoperatively will significantly decrease postoperative shoulder pain and analgesic consumption. After obtaining written informed consent, 108 patients were prospectively randomized into two groups. In the control group, patients underwent standard gynecologic laparoscopic procedures; then after passive deflation of the pneumoperitoneum at the end of the surgery, the patients were placed in supine head up position in the post anesthesia care unit (PACU) and received our institution's common postoperative care. Patients in the intervention group were subjected to the same maneuver but were positioned in a Trendelenburg position (20 °) once fully awake and cooperative in the PACU and retained this position for the first 24 h. Numerical rating scale (NRS) was used to assess shoulder pain and nausea upon patient arrival to the PACU, at 4, 6, 12 (primary outcome) and 24 h postoperatively. Time to first rescue pain medication, total rescue pain medications and overall satisfaction with pain control were recorded. 101 patients were included in the final data analysis.

RESULTS

Both groups were comparable in terms of baseline characteristics. NRS pain scores were significantly lower in the intervention group at 12 h compared to the control group (0 [0-1] versus 5 [1-4], p < 0.001), furthermore improvement in postoperative shoulder pain between time of arrival to PACU (time zero) and 12 h postoperatively was significantly higher in patients allocated to the experimental group compared to the control group. Pain scores were significantly lower in patients allocated to the experimental group versus the control group (0 [0-1] versus 5 [1-4], p < 0.001).

CONCLUSION

In conclusion, Trendelenburg position is an easy non-pharmacologic intervention that is beneficial in reducing postoperative shoulder pain following gynecologic laparoscopic surgery.

TRIAL REGISTRATION

Retrospectively registered at Clinicaltrials.gov, registration number NCT04129385,  date of registration: June 28, 2019.

Comparison of volume-controlled, pressure-controlled, and pressure-controlled volume-guaranteed ventilation during robot-assisted laparoscopic gynecologic surgery in the Trendelenburg position

Background: Pressure-controlled ventilation volume-guaranteed (PCV-VG) is being increasingly used for ventilation during general anesthesia. Carbon dioxide (CO₂) pneumoperitoneum in the Trendelenburg position is routinely used during robot-assisted laparoscopic gynecologic surgery. Here, we hypothesized that PCV-VG would reduce peak inspiratory pressure (Ppeak), compared to volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV). Methods: In total, 60 patients were enrolled in this study and randomly assigned to receive VCV, PCV, or PCV-VG. Hemodynamic variables, respiratory variables, and arterial blood gases were measured in the supine position 15 minutes after the induction of anesthesia (T0), 30 and 60 minutes after CO₂ pneumoperitoneum and Trendelenburg positioning (T1 and T2, respectively), and 15 minutes after placement in the supine position at the end of anesthesia (T3). Results: The Ppeak was higher in the VCV group than in the PCV and PCV-VG groups (p=0.011). Mean inspiratory pressure (Pmean) was higher in the PCV and PCV-VG groups than in the VCV group (p<0.001). Dynamic lung compliance (Cdyn) was lower in the VCV group than in the PCV and PCV-VG groups (p=0.001). Conclusion: Compared to VCV, PCV and PCV-VG provided lower Ppeak, higher Pmean, and improved Cdyn, without significant differences in hemodynamic variables or arterial blood gas results during robot-assisted laparoscopic gynecologic surgery with Trendelenburg position.

[Cardiorespiratory effects of perioperative positioning techniques]

The supine position is still the most frequently used type of positioning during surgical procedures. Positions other than the supine position lead to physiological alterations that have a relevant influence on the course of anesthesia and surgery. As a matter of principle, hemodynamic stability is at risk because venous blood is pooled in the lower positioned body parts. In addition, head down positions (Trendelenburg position) may lead to an impairment of respiratory function by reducing lung volumes as well as lung compliance. Upright positions (beach chair position) are characterized by a relative hypovolemia accompanied by a reduction of mean arterial pressure, cardiac output and stroke volume, whereas pulmonary functions remain unchanged. Some severe adverse events have been described in the literature (e.g. intraoperative apoplexy, postoperative blindness). The pathophysiological principles and effects of hemodynamic alterations as well as potential strategies to avoid complications are presented and discussed in this lead article. Head down positions, especially the Trendelenburg position, cause a relative (intrathoracic) hypervolemia and an increase in cardiac preload that is usually well-tolerated in patients without heart problems; however, the Trendelenburg position, especially if combined with a capnoperitoneum, significantly impairs pulmonary function, can have a negative effect on intracerebral pressure and may reduce blood flow of intra-abdominal organs. The pathophysiological intraoperative changes caused by Trendelenburg positioning are described and approaches suitable for risk reduction are discussed. The prone position and lateral decubitus position have little influence on the intraoperative homeostasis. Nevertheless, there is an ongoing discussion concerning the efficacy of a 15° left lateral position during caesarean section, which is also discussed in a separate section of this review.

The Effects of Positioning on the Volume/Location of the Internal Jugular Vein Using 2-Dimensional Tracked Ultrasound

OBJECTIVE

To investigate the effects of different positioning on the volume/location of the internal jugular vein (IJV) using 2-dimensional (2D) tracked ultrasound.

DESIGN

This was a prospective, observational study.

SETTING

Local research institute.

PARTICIPANTS

Healthy volunteers.

INTERVENTIONS

Twenty healthy volunteers were scanned in the following 6 positions: (1) supine with head neutral, rotated 15 and 30 degrees to the left and (2) 5-, 10-, and 15-degree Trendelenburg position with head neutral. In each position the volunteer's neck was scanned using a 2D ultrasound probe tracked with a magnetic tracker. These spatially tracked 2D images were collected and reconstructed into a 3D volume of the IJV and carotid artery. This 3D ultrasound volume then was segmented to obtain a 3D surface on which measurements and calculations were performed.

MEASUREMENTS AND MAIN RESULTS

The measurements included average cross-section area (CSA), CSA along the length of IJV, and average overlap rate. CSA (mm²) in the supine and 5-, 10-, and 15-degree Trendelenburg positions were as follows: 86.7 ± 44.8, 104.3 ± 54.5, 119.1 ± 58.6, and 133.7 ± 53.3 (p < 0.0001). CSA enlarged with the increase of Trendelenburg degree. Neither Trendelenburg position nor head rotation showed a correlation with overlap rate.

CONCLUSIONS

Trendelenburg position significantly increased the CSA of the IJV, thus facilitating IJV cannulation. This new 3D reconstruction method permits the creation of a 3D volume through a tracked 2D ultrasound scanning system with image acquisition and integration and may prove useful in providing the user with a "road map" of the vascular anatomy of a patient's neck or other anatomic structures.

The tidal volume challenge improves the reliability of dynamic preload indices during robot-assisted laparoscopic surgery in the Trendelenburg position with lung-protective ventilation

Background

The reliability of pulse pressure variation (PPV) and stroke volume variation (SVV) is controversial under pneumoperitoneum. In addition, the usefulness of these indices is being called into question with the increasing adoption of lung-protective ventilation using low tidal volume (V_T) in surgical patients. A recent study indicated that changes in PPV or SVV obtained by transiently increasing V_T (V_T challenge) accurately predicted fluid responsiveness even in critically ill patients receiving low V_T. We evaluated whether the changes in PPV and SVV induced by a V_T challenge predicted fluid responsiveness during pneumoperitoneum.

Methods

We performed an interventional prospective study in patients undergoing robot-assisted laparoscopic surgery in the Trendelenburg position under lung-protective ventilation. PPV, SVV, and the stroke volume index (SVI) were measured at a V_T of 6 mL/kg and 3 min after increasing the V_T to 8 mL/kg. The V_T was reduced to 6 mL/kg, and measurements were performed before and 5 min after volume expansion (infusing 6% hydroxyethyl starch 6 ml/kg over 10 min). Fluid responsiveness was defined as ≥15% increase in the SVI.

Results

Twenty-four of the 38 patients enrolled in the study were responders. In the receiver operating characteristic curve analysis, an increase in PPV > 1% after the V_T challenge showed excellent predictive capability for fluid responsiveness, with an area under the curve (AUC) of 0.95 [95% confidence interval (CI), 0.83–0.99, P < 0.0001; sensitivity 92%, specificity 86%]. An increase in SVV > 2% after the V_T challenge predicted fluid responsiveness, but showed only fair predictive capability, with an AUC of 0.76 (95% CI, 0.60–0.89, P < 0.0006; sensitivity 46%, specificity 100%). The augmented values of PPV and SVV following V_T challenge also showed the improved predictability of fluid responsiveness compared to PPV and SVV values (as measured by V_T) of 6 ml/kg.

Conclusions

The change in PPV following the V_T challenge has excellent reliability in predicting fluid responsiveness in our surgical population. The change in SVV and augmented values of PPV and SVV following this test are also reliable.

Trial registration

This trial was registered with Clinicaltrials.gov, NCT03467711, 10th March 2018.

Changes of cerebral regional oxygen saturation during pneumoperitoneum and Trendelenburg position under propofol anesthesia: a prospective observational study

BACKGROUND

We evaluated the change of cerebral regional tissue oxygen saturation (rSO₂) along with the pneumoperitoneum and the Trendelenburg position. We also assessed the relationship between the change of rSO₂ and the changes of mean arterial blood pressure (MAP), heart rate (HR), arterial carbon dioxide tension (PaCO₂), arterial oxygen tension (PaO₂), or arterial oxygen saturation (SaO₂).

METHODS

Forty-one adult patients who underwent a robotic assisted endoscopic prostatic surgery under propofol and remifentanil anesthesia were involved in this study. During the surgery, a pneumoperitoneum was established using carbon dioxide. Measurements of rSO₂, MAP, HR, PaCO₂, PaO₂, and SaO₂ were performed before the pneumoperitoneum (baseline), every 5 min after the onset of pneumoperitoneum, before the Trendelenburg position. After the onset of the Trendelenburg position, rSO₂, MAP, HR were recorded at 5, 10, 20, 30, 45, and 60 min, and PaCO₂, PaO₂, and SaO₂ were measured at 10, 30, and 60 min.

RESULTS

Before the pneumoperitoneum, left and right rSO₂ were 67.9 ± 6.3% and 68.5 ± 7.0%. Ten minutes after the onset of pneumoperitoneum, significant increase in the rSO₂ was observed (left: 69.6 ± 5.9%, right: 70.6 ± 7.4%). During the Trendelenburg position, the rSO₂ increased initially and peaked at 5 min (left: 72.2 ± 6.5%, right: 73.1 ± 7.6%), then decreased. Multiple regression analysis showed that change of rSO₂ correlated with MAP and PaCO₂.

CONCLUSIONS

Pneumoperitoneum and the Trendelenburg position in robotic-assisted endoscopic prostatic surgery did not worsen cerebral oxygenation. Arterial blood pressure is the critical factor in cerebral oxygenation.

TRIAL REGISTRATION

Japan Primary Registries Network (JPRN); UMIN-CTR ID; UMIN000026227 (retrospectively registered).

Comparison of the effect of the right lateral tilt position and Trendelenburg position on the right internal jugular vein in healthy volunteers: A prospective observational study

BACKGROUND

Central venous cannulation is an invasive procedure commonly used by many physicians. The aim of this study was to evaluate the effects of the right lateral tilt position on the cross-sectional area and size of the right internal jugular vein, and the relationship between the right internal jugular vein and the carotid artery.

METHOD

Forty healthy volunteers aged over 18 years were included in this prospective, observational study. The right internal jugular vein cross-sectional area and the anatomic relationship with the carotid artery were assessed using ultrasound imaging. This measurement was repeated for four positions (baseline position, 10° right tilt position, 10° Trendelenburg position, and 10° right tilt + 10° Trendelenburg position). The head was rotated 30° to the contralateral side in all patients.

RESULTS

The mean (standard deviation) right internal jugular vein cross-sectional area, transverse diameter, and anteroposterior diameter were significantly increased with the Trendelenburg position and 10° right tilt + 10° Trendelenburg position (p < 0.05). There were no significant differences in right internal jugular vein cross-sectional area, transverse diameter, and anteroposterior diameter between the baseline position and 10° right tilt position (p > 0.05).

CONCLUSION

We found that the right lateral tilt position had no effect on the internal jugular vein cross-sectional area and that the Trendelenburg position was still the most valid position for safely increasing the right internal jugular vein cross-sectional area.