A comparative analysis of the effects of sevoflurane and propofol on cerebral oxygenation during steep Trendelenburg position and pneumoperitoneum for robotic-assisted laparoscopic prostatectomy

The intraoperative management of robotic-assisted laparoscopic prostatectomy

PURPOSE OF REVIEW

Robotic-assisted laparoscopic radical prostatectomy has become the second most commonly performed robotic surgical procedure worldwide, therefore, anesthesiologists should be aware of the intraoperative pathophysiological consequences. The aim of this narrative review is to report the most recent updates regarding the intraoperative management of anesthesia, ventilation, hemodynamics and central nervous system, during robotic-assisted laparoscopic radical prostatectomy.

RECENT FINDINGS

Surgical innovations and the advent of new technologies make it imperative to optimize the anesthesia management to provide the most holistic approach possible. In addition, an ageing population with an increasing burden of comorbidities requires multifocal attention to reduce the surgical stress.

SUMMARY

Total intravenous anesthesia (TIVA) and balanced general anesthesia are similar in terms of postoperative complications and hospital stay. Reversal of rocuronium is associated with shorter hospital stay and postanesthesia recovery time. Adequate PEEP levels improve oxygenation and driving pressure, and the use of a single recruitment maneuver after the intubation reduces postoperative pulmonary complications. Restrictive intravenous fluid administration minimizes bladder-urethra anastomosis complications and facial edema. TIVA maintains a better autoregulation compared with balanced general anesthesia. Anesthesiologists should be able to optimize the intraoperative management to improve outcomes.

Influence of pneumoperitoneum and head-down maneuver on the cerebral microvasculature in rabbits

BACKGROUND

With recent advances in robot-assisted techniques, an increasing number of surgeries are being performed with pneumoperitoneum and head-down maneuver (HDM) that may affect the cerebral microcirculation. For the first time, this study investigated the direct influence of pneumoperitoneum and HDM on the cerebral microvasculature in rabbits.

METHODS

Adult male rabbits were randomly allocated to the following groups (n = 7 each): control, pneumoperitoneum alone (P), and pneumoperitoneum with HDM (P + HDM) for 120 min. A closed cranial window was installed above the parietal bone to visualize the pial microvasculature. Pial arteriolar diameter and hemodynamic and blood gas parameters were measured during the 140-min observation period. Brain edema was assessed by evaluation of the brain water content at the end of the experiment.

RESULTS

Rabbits in the P and P + HDM groups exhibited a similar degree of immediate pial arteriolar dilation following the initiation of both P and P + HDM (P: 1.11 ± 0.03, p = 0.0044 and P + HDM: 1.07 ± 0.02, p = 0.0004, relative changes from the baseline value by defining the baseline as one). In the P + HDM group, pial arteriole diameter returned to the baseline level following the discontinuation of pneumoperitoneum and HDM (1.05 ± 0.03, p = 0.0906, vs. baseline). In contrast, the pial arterioles remained dilated as compared to the baseline level in the P group after discontinuation of pneumoperitoneum. There were no changes in pial arteriole diameter in the animals in the control group. Heart rate, blood gas parameters, and brain water content were not significantly different between the groups.

CONCLUSION

The pial arterioles dilated immediately after pneumoperitoneum with or without HDM. The pial arterioles remained dilated 20 min after discontinuation of pneumoperitoneum alone but constricted upon discontinuation of pneumoperitoneum plus HDM. Pneumoperitoneum and HDM for 2 h did not cause brain edema.

Effects of sevoflurane versus propofol on cerebral autoregulation during anaesthesia for robot-assisted laparoscopic prostatectomy

Robot-assisted laparoscopic prostatectomy requires a pneumoperitoneum combined with steep Trendelenburg positioning, and these conditions can be associated with impairment of cerebral autoregulation. The objective of this study was to determine if choice of anaesthetic agent affects the preservation of cerebral autoregulation during robot-assisted laparoscopic prostatectomy. We randomly assigned 30 patients to maintenance of general anaesthesia with either propofol or sevoflurane. Cerebral autoregulation was tested by administration of intravenous phenylephrine to increase mean arterial pressure from approximately 80 mmHg to 100 mmHg while assessing cerebral blood flow using transcranial Doppler ultrasonography. Autoregulation was first tested in the supine position and then approximately once every hour after Trendelenburg positioning. The main outcome measure was the result of the final autoregulation test prior to completion of surgery. At that time, we found cerebral autoregulation to be significantly impaired in six of the 15 patients receiving sevoflurane and none of the 15 patients receiving propofol (P = 0.02). However, it should be noted that some patients in the propofol group had impaired autoregulation on earlier tests. In conclusion, we found that autoregulation during robot-assisted laparoscopic prostatectomy is less likely to be impaired with propofol compared to sevoflurane anaesthesia, particularly towards the end of the surgery.

Comparison of the Effects of Propofol and Sevoflurane Anesthesia on Optic Nerve Sheath Diameter in Robot-Assisted Laparoscopic Gynecology Surgery: A Randomized Controlled Trial

Optic nerve sheath diameter (ONSD) is used as a surrogate parameter for intracranial pressure. This study was conducted to evaluate the effect of the anesthetics (sevoflurane and propofol) on ONSD in women undergoing robotic surgery. The 42 patients who were scheduled for robot-assisted gynecology surgery were randomly allocated to the sevoflurane group or the propofol group. ONSD was recorded at 10 min after the induction of anesthesia (T0); 5 min, 20 min, and 40 min after carbon dioxide pneumoperitoneum was induced and the patients were put in a steep Trendelenburg position (T1, T2, and T3, respectively); and at skin closure after desufflation of the pneumoperitoneum (T4). Patients were observed for postoperative nausea and vomiting (PONV) during the immediate postoperative period. The propofol group had significantly lower ONSD than the sevoflurane group at T3. Mean ONSD values continuously increased from T0 to T3 in both groups. Two patients in the sevoflurane group experienced PONV. This study suggests that propofol anesthesia caused a lower increase in ONSD than sevoflurane anesthesia.

Extremely low bispectral index value during robotic-assisted laparoscopic prostatectomy: A case report

The steep Trendelenburg position and pneumoperitoneum during surgery may affect intracranial pressure and cerebral oxygenation, which in turn may affect the values of the bispectral index (BIS). Prolonged maintenance of the Trendelenburg position and pneumoperitoneum may impair cerebrovascular autoregulation. We present a case of a patient with an extremely low BIS value during robotic-assisted laparoscopic prostatectomy (RALP). We managed the patient under general anesthesia and he showed a prominent decrease in BIS values 6 h after the start of surgery. Suppression ratio (SR) of electroencephalography (EEG) is also decreased, suggesting that the brain activity decreased. The BIS value increased quickly after the Trendelenburg position was released and the anesthesia was terminated. The patient recovered without any neurological deficits and was discharged. Steep Trendelenburg position and pneumoperitoneum can cause EEG abnormalities.

Sevoflurane-Remifentanil Versus Propofol-Remifentanil Anesthesia During Noncardiac Surgery for Patients with Coronary Artery Disease - A Prospective Study Between 2016 and 2017 at a Single Center

BACKGROUND Volatile anesthesia possesses cardioprotective properties, and it is widely used in patients undergoing coronary artery bypass surgery, but no randomized controlled trials (RCTs) are available on the use of sevoflurane-remifentanil versus propofol-remifentanil anesthesia for patients with coronary artery disease (CAD) during noncardiac surgery. This study was designed to compare the 2 different types of general anesthesia in patients with CAD undergoing noncardiac surgery at a single center. MATERIAL AND METHODS Patients with CAD undergoing noncardiac surgery were enrolled in an RCT conducted between March 2016 and December 2017. The participants were randomized to receive either sevoflurane-remifentanil or propofol-remifentanil anesthesia. The primary endpoint was occurrence of in-hospital cardiovascular events. The secondary endpoints included delirium, postoperative nausea and vomiting (PONV), Intensive Care Unit (ICU) length of stay (LOS), in-hospital morbidity and mortality, and hospital LOS. RESULTS A total of 164 participants completed the study (sevoflurane: 81; propofol: 83). The occurrence of in-hospital cardiovascular events did not differ between the 2 groups (42.6% vs 39.4%, P=0.86). The occurrence of delirium did not differ between the 2 groups after the operation. PONV had a higher frequency after sevoflurane anesthesia at 48 h compared with propofol. In-hospital morbidity and mortality, ICU LOS, and hospital LOS were similar between the 2 groups (all P>0.05). At 30 days after surgery, no between-group differences in cardiac morbidity and mortality were observed. CONCLUSIONS In this study, anesthesia using sevoflurane-remifentanil did not provide additional postoperative cardioprotection in comparison with propofol-remifentanil in patients with CAD undergoing noncardiac surgery.

The effect of different levels of pneumoperitoneum pressures on regional cerebral oxygenation during robotic assisted laparoscopic prostatectomy

Background/aim

This study aimed to evaluate the effect of low- and high-pressure pneumoperitoneum pressures applied during robotic-assisted laparoscopic prostatectomy (RALP) using near-infrared spectroscopy (NIRS) on regional cerebral oxygenation saturation (rSO₂).

Materials and methods

The prospective, comparative, and observational study included patients aged 18–80 years, with the American Society of Anesthesiologists (ASA) physical status I-II, who would undergo elective RALP. The patients were divided into two groups (12 mmHg of pneumoperitoneum pressure group, n=22 and 15 mmHg of pneumoperitoneum pressure group, n=23). Patients’ demographic data, durations of anesthesia, surgery, pneumoperitoneum, and Trendelenburg position, intraoperative estimated blood loss, fluid therapy, urine output, hemodynamic and respiratory data, and rSO₂ values were recorded at regular intervals.

Results

The rSO₂ values increased significantly during the pneumoperitoneum combined with steep Trendelenburg position (from t3 to t6 ) and at the end of the surgery ( t7 ) in both groups, compared to the values 5 min after the onset of pneumoperitoneum in the supine position ( t2 ) (P < 0.05), but no statistical significance was observed between the two groups. No cerebral desaturation was observed in any of our patients. Hemodynamic and respiratory parameters were preserved in both groups. The blood lactate levels were significantly higher in patients operated at high-pressure pneumoperitoneum, compared to those with low-pressure pneumoperitoneum (P < 0.05).

Conclusion

We believe that low-pressure pneumoperitoneum, especially in robotic surgeries, such as robotic-assisted laparoscopic prostatectomy (RALP), can be applied safely.

Forehead Regional Oxygen Saturation (rSO2)-Related Ear-Level Arterial Pressure and Lower Thigh rSO2 in the Steep Trendelenburg Position with CO2 Pneumoperitoneum and the Beach Chair Position

Introduction

Regional oxygen saturation (rSO2) reflects tissue perfusion. This observational study aimed to examine the change in the forehead and lower thigh rSO2 associated with intraoperative posture, anesthesia regimen, or mean arterial pressure (mAP) at heart and external auditory meatus (ear) levels.

Methods

Patients undergoing robot-assisted laparoscopic radical prostatectomy in the Trendelenburg position at 30° with pneumoperitoneum (TPP) or arthroscopic shoulder surgery in the beach chair position at 70° (BCP) under desflurane-remifentanil (D/R) or propofol-remifentanil (P/R) anesthesia were examined. Bilateral forehead and lower thigh rSO2 values and mean radial artery pressure were measured simultaneously at heart and ear levels.

Results

In TPP, there were no differences under anesthesia regimens in the forehead or lower thigh rSO2change, although one patient with an absolute lower thigh rSO2 of ≤50% in the lithotomy position complained of transient limb pain. No correlation was observed between rSO2 and mAP. In BCP, forehead rSO2 decreased and lower thigh rSO2 increased under either of the anesthesia regimens. The coefficient of correlation between forehead rSO2 andheart-level and ear-level mAP was 0.341 and 0.236, respectively.

Conclusions

There were no differences under anesthesia regimens in the changes of forehead rSO2 and lower thigh rSO2. In TPP, significant changes in forehead rSO2 and lower thigh rSO2 were not observed. Monitoring lower thigh rSO2 might be useful for preventing lower extremity pain. In BCP, forehead rSO2 decreased and lower thigh rSO2 increased from the supine position to the BCP. To prevent brain damage, anesthesiologists should pay attention to heart- and ear-level mAP.

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.

[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.

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).

Effects of pneumoperitoneum and steep Trendelenburg position on cerebral hemodynamics during robotic-assisted laparoscopic radical prostatectomy: A randomized controlled study

BACKGROUND

We evaluated the relationship between ultrasonographical acquired parameters and short-term postoperative cognitive function in patients undergoing robotic-assisted radical prostatectomy (RALP).

METHODS

Ninety elderly patients scheduled for RALP had their optic nerve sheath diameter (ONSD), the cross-sectional area (CSA) of the internal jugular vein (IJV) and the IJV valve (IJVV) competency assessed by ultrasound. The patients were analyzed in 2 groups based on whether displayed IJVV incompetency (IJVVI). The 3 parameters were measured before anesthesia (T0), immediately after induction of general anesthesia (T1), 5 minutes after establishing pneumoperitoneum (T2), 5 minutes after placing the patient in the Trendelenburg position (T3), and 5 minutes after the release of the pneumoperitoneum in the supine position (T4). Regional cerebral tissue oxygen saturation (rSO2) was also measured by near-infrared spectroscopy intraoperatively. The Mini-Mental State Examination (MMSE) and Confusion Assessment Method (CAM) were performed the day before surgery and on postoperative days 1, 3, and 7.

RESULTS

We found that 52% of patients had evidence of IJVVI after being placed in the Trendelenburg position after pneumoperitoneum was established (T4). Patient with IJVVI showed a significant increase of ONSD and CSA at T1, T2, T3, T4 but there was no associated decrease in rSO2. MMSE scores were reduced at postoperative day 1 and the 7 patients that developed postoperative delirium came from Group IJVVI.

CONCLUSIONS

Our observations suggest that elderly patients that show IJVVI after adequate positioning for RALP may develop elevated intracranial pressure as well as mildly compromised postoperative cognitive function in the short term.

Effects of Carbon Dioxide Insufflation and Trendelenburg Position on Brain Oxygenation During Laparoscopy in Children

PURPOSE

Laparoscopic appendectomy has become more popular compared with the open appendectomy in children, but there are limited data on the effects of pneumoperitoneum and Trendelenburg position on cerebral oxygenation. This study was designed to evaluate the changes in cerebral saturation using near-infrared spectroscope during laparoscopic surgery in children.

METHODS

The children underwent laparoscopic (LAP Group, n=22) or open appendectomy (OPEN Group, n=22). Right and left cerebral oxygenation (RScO2-LScO2), heart rate (HR), mean arterial pressure (MAP), end-tidal CO2pressure (PETCO2), and peripheral oxygen saturations (SpO2) were recorded between anesthesia induction (T0, baseline), after induction (T1), after intubation (T2), 5 minutes after intubation (T3), 5 minutes after pneumoperitoneum-15th minute at OPEN (T4), 5 minutes after Trendelenburg-20th minute at OPEN (T5), 30 minutes after pneumoperitoneum-45th minute at OPEN (T6), 5 minutes after supine position-skin suturing at OPEN (T7), 5 minutes postextubation (T8).

RESULTS

Groups were similar with respect to their demographic data. In LAP group, a significant increase in HR was recorded at T5. No significant difference was observed in the MAP, PETCO2, SpO2, RScO2, and LScO2 values between the groups. There was a significant increase in the perioperative T1 to T8 values compared with the T0 values in LScO2 of the LAP group.

CONCLUSIONS

Our results suggest that pneumoperitoneum and Trendelenburg position does not alter the hemodynamic values and can be safely performed in children without altering regional brain oxygenation levels.

Intravenous versus inhalational maintenance of anaesthesia for postoperative cognitive outcomes in elderly people undergoing non-cardiac surgery

BACKGROUND

The use of anaesthetics in the elderly surgical population (more than 60 years of age) is increasing. Postoperative delirium, an acute condition characterized by reduced awareness of the environment and a disturbance in attention, typically occurs between 24 and 72 hours after surgery and can affect up to 60% of elderly surgical patients. Postoperative cognitive dysfunction (POCD) is a new-onset of cognitive impairment which may persist for weeks or months after surgery.Traditionally, surgical anaesthesia has been maintained with inhalational agents. End-tidal concentrations require adjustment to balance the risks of accidental awareness and excessive dosing in elderly people. As an alternative, propofol-based total intravenous anaesthesia (TIVA) offers a more rapid recovery and reduces postoperative nausea and vomiting. Using TIVA with a target controlled infusion (TCI) allows plasma and effect-site concentrations to be calculated using an algorithm based on age, gender, weight and height of the patient.TIVA is a viable alternative to inhalational maintenance agents for surgical anaesthesia in elderly people. However, in terms of postoperative cognitive outcomes, the optimal technique is unknown.

OBJECTIVES

To compare maintenance of general anaesthesia for elderly people undergoing non-cardiac surgery using propofol-based TIVA or inhalational anaesthesia on postoperative cognitive function, mortality, risk of hypotension, length of stay in the postanaesthesia care unit (PACU), and hospital stay.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 11), MEDLINE (1946 to November 2017), Embase (1974 to November 2017), PsycINFO (1887 to November 2017). We searched clinical trials registers for ongoing studies, and conducted backward and forward citation searching of relevant articles.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) with participants over 60 years of age scheduled for non-cardiac surgery under general anaesthesia. We planned to also include quasi-randomized trials. We compared maintenance of anaesthesia with propofol-based TIVA versus inhalational maintenance of anaesthesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias, and synthesized findings.

MAIN RESULTS

We included 28 RCTs with 4507 randomized participants undergoing different types of surgery (predominantly cardiovascular, laparoscopic, abdominal, orthopaedic and ophthalmic procedures). We found no quasi-randomized trials. Four studies are awaiting classification because we had insufficient information to assess eligibility.All studies compared maintenance with propofol-based TIVA versus inhalational maintenance of anaesthesia. Six studies were multi-arm and included additional TIVA groups, additional inhalational maintenance or both. Inhalational maintenance agents included sevoflurane (19 studies), isoflurane (eight studies), and desflurane (three studies), and was not specified in one study (reported as an abstract). Some studies also reported use of epidural analgesia/anaesthesia, fentanyl and remifentanil.We found insufficient reporting of randomization methods in many studies and all studies were at high risk of performance bias because it was not feasible to blind anaesthetists to study groups. Thirteen studies described blinding of outcome assessors. Three studies had a high of risk of attrition bias, and we noted differences in the use of analgesics between groups in six studies, and differences in baseline characteristics in five studies. Few studies reported clinical trials registration, which prevented assessment of risk of selective reporting bias.We found no evidence of a difference in incidences of postoperative delirium according to type of anaesthetic maintenance agents (odds ratio (OR) 0.59, 95% confidence interval (CI) 0.15 to 2.26; 321 participants; five studies; very low-certainty evidence); we noted during sensitivity analysis that using different time points in one study may influence direction of this result. Thirteen studies (3215 participants) reported POCD, and of these, six studies reported data that could not be pooled; we noted no difference in scores of POCD in four of these and in one study, data were at a time point incomparable to other studies. We excluded one large study from meta-analysis because study investigators had used non-standard anaesthetic management and this study was not methodologically comparable to other studies. We combined data for seven studies and found low-certainty evidence that TIVA may reduce POCD (OR 0.52, 95% CI 0.31 to 0.87; 869 participants).We found no evidence of a difference in mortality at 30 days (OR 1.21, 95% CI 0.33 to 4.45; 271 participants; three studies; very low-certainty evidence). Twelve studies reported intraoperative hypotension. We did not perform meta-analysis for 11 studies for this outcome. We noted visual inconsistencies in these data, which may be explained by possible variation in clinical management and medication used to manage hypotension in each study (downgraded to low-certainty evidence); one study reported data in a format that could not be combined and we noted little or no difference between groups in intraoperative hypotension for this study. Eight studies reported length of stay in the PACU, and we did not perform meta-analysis for seven studies. We noted visual inconsistencies in these data, which may be explained by possible differences in definition of time points for this outcome (downgraded to very low-certainty evidence); data were unclearly reported in one study. We found no evidence of a difference in length of hospital stay according to type of anaesthetic maintenance agent (mean difference (MD) 0 days, 95% CI -1.32 to 1.32; 175 participants; four studies; very low-certainty evidence).We used the GRADE approach to downgrade the certainty of the evidence for each outcome. Reasons for downgrading included: study limitations, because some included studies insufficiently reported randomization methods, had high attrition bias, or high risk of selective reporting bias; imprecision, because we found few studies; inconsistency, because we noted heterogeneity across studies.

AUTHORS' CONCLUSIONS

We are uncertain whether maintenance with propofol-based TIVA or with inhalational agents affect incidences of postoperative delirium, mortality, or length of hospital stay because certainty of the evidence was very low. We found low-certainty evidence that maintenance with propofol-based TIVA may reduce POCD. We were unable to perform meta-analysis for intraoperative hypotension or length of stay in the PACU because of heterogeneity between studies. We identified 11 ongoing studies from clinical trials register searches; inclusion of these studies in future review updates may provide more certainty for the review outcomes.

Effect of Mannitol on Ultrasonographically Measured Optic Nerve Sheath Diameter as a Surrogate for Intracranial Pressure During Robot-Assisted Laparoscopic Prostatectomy with Pneumoperitoneum and the Trendelenburg Position

INTRODUCTION

CO₂ pneumoperitoneum and the steep Trendelenburg position during robot-assisted laparoscopic prostatectomy (RALP) can increase intracranial pressure (ICP). Mannitol is widely used to treat increased ICP. However, no studies to date have specifically evaluated the effect of mannitol on ICP in patients undergoing RALP. Ultrasonographic measurement of the optic nerve sheath diameter (ONSD) is considered a reliable technique to noninvasively evaluate the ICP. Therefore, this study compared ONSDs as a surrogate for ICP before and after mannitol administration in prostate cancer patients undergoing RALP.

METHODS

Mannitol (0.5 g/kg) was administered after pneumoperitoneum establishment and shifting to the Trendelenburg position. ONSDs were measured at six predetermined time points: 10 minutes after anesthesia induction (T0); 5 minutes after pneumoperitoneum and the Trendelenburg position before mannitol administration (T1); 30 minutes (T2), 60 minutes (T3), and 90 minutes (T4) after completion of mannitol administration during pneumoperitoneum and the Trendelenburg position; and at skin closure in the supine position (T5). Moreover, intraoperative hemodynamic and respiratory variables were evaluated simultaneously.

RESULTS

Thirty-six patients were analyzed. ONSDs were significantly lower at T2, T3, and T4 than at T1 (all p < 0.001), with the greatest decrease observed at T4 compared with T1 (4.46 ± 0.2 mm vs 4.81 ± 0.3 mm, p < 0.001). Regional cerebral oxygen saturation, cardiac output, corrected flow time, peak velocity, body temperature, arterial CO₂ partial pressure, peak airway pressure, plateau airway pressure, dynamic compliance, and static compliance were not significantly different during pneumoperitoneum and the Trendelenburg position; however, mean arterial blood pressure and heart rate were significantly different.

CONCLUSIONS

Mannitol decreases the ONSD in patients undergoing RALP with CO₂ pneumoperitoneum and the steep Trendelenburg position. This result provides useful information on the beneficial effects of mannitol administration on prostate cancer patients who may develop increased ICP during RALP.