Cerebral oximetry in high-risk surgical patients: where are we?

PURPOSE OF REVIEW

This review aims to summarize the latest evidence on the role of near-infrared spectroscopy (NIRS) in monitoring cerebral oxygenation in high-risk surgical patients, including both cardiac and noncardiac surgeries, and to present a new algorithm for its application.

RECENT FINDINGS

NIRS effectively measures brain oxygen saturation noninvasively, proving valuable in cardiac surgeries to reduce neurological complications, though its impact on nonneurological outcomes is less clear. In noncardiac surgeries, NIRS can help prevent complications like postoperative cognitive dysfunction, particularly in high-risk and major surgeries. Studies highlight the variability of cerebral oxygenation impacts based on surgical positions, with mixed results in positions like the beach chair and sitting positions. A structured algorithm for managing cerebral desaturation has been proposed to optimize outcomes by addressing multiple factors contributing to blood oxygen content and delivery.

SUMMARY

Despite its limitations, including spatial resolution and interindividual variability, NIRS is a useful tool for intraoperative cerebral monitoring. Further studies are needed to confirm its broader applicability in noncardiac surgeries, but current evidence supports its role in reducing postoperative complications especially in cardiac surgeries.

Effect of optimizing cerebral oxygen saturation on postoperative delirium in older patients undergoing one-lung ventilation for thoracoscopic surgery

OBJECTIVES

This randomized controlled trial investigated whether the regional cerebral oxygenation saturation (rScO2)-guided lung-protective ventilation strategy could improve brain oxygen and reduce the incidence of postoperative delirium (POD) in patients older than 65 years.

METHODS

This randomized controlled trial enrolled 120 patients undergoing thoracic surgery who received one-lung ventilation (OLV). Patients were randomly assigned to the lung-protective ventilation group (PV group) or rScO2-oriented lung-protective ventilation group (TPV group). rScO2 was recorded during the surgery, and the occurrence of POD was assessed.

RESULTS

The incidence of POD 3 days after surgery-the primary outcome-was significantly lower in the TPV group (23.3% versus 8.5%). Meanwhile, the levels of POD-related biological indicators (S100β, neuron-specific enolase, tumor necrosis factor-α) were lower in the TPV group. Considering the secondary outcomes, both groups exhibited a lower oxygenation index after OLV, whereas partial pressure of carbon dioxide and mean arterial pressure were significantly increased in the TPV group. In addition, minimum rScO2 during surgery and mean rScO2 were higher in the TPV group than in the PV group.

CONCLUSION

Continuous intraoperative monitoring of brain tissue oxygenation and active intervention measures guided by cerebral oxygen saturation are critical for improving brain metabolism and reducing the risk of POD.

The relationship between perioperative central venous oxygen saturation and postoperative complications in highly invasive gastroenterological surgery

Purpose

Operations for malignant diseases of the bile duct, pancreas, and esophagus are the most invasive gastroenterological surgeries. The frequency of complications after these surgeries is high, which affects the postoperative course and mortality. In patients who undergo these types of surgeries, continuous monitoring of the perioperative central venous oxygen saturation (ScvO2) is possible via a central venous catheter. We aimed to investigate the relationship between continuously monitored perioperative ScvO2 values and postoperative complications.

Methods

The medical records of 115 patients who underwent highly invasive gastroenterological surgeries and ScvO2 monitoring from April 2012 to March 2014 were analyzed. Sixty patients met the inclusion criteria, and their ScvO2 levels were continuously monitored perioperatively. The relationship between ScvO2 levels and major postoperative complications, defined as Clavien-Dindo grade ≥ III, was examined using uni- and multivariate analysis.

Results

Thirty patients developed major postoperative complications. The adequate cut-off value derived from receiver operating curves of the postoperative average ScvO2 levels for predicting major complications was 75%. Multivariate analysis revealed that low average postoperative ScvO2 levels (p = 0.016) and blood loss ≥ 1000 mL (p = 0.039) were significant predictors of major postoperative complications.

Conclusions

Low perioperative ScvO2 values were associated with an increased risk of major postoperative complications. Continuous ScvO2 monitoring will help prevent postoperative complications.

Effects of different anesthetic regimens on postoperative cognitive function of elderly patients undergoing thoracic surgery: a double-blinded randomized controlled trial

OBJECTIVE

Postoperative cognitive dysfunction (POCD) is a serious surgical complication. We assessed the different POCD incidences between anesthesia using sevoflurane and sevoflurane combined with dexmedetomidine, with propofol-based sedation in elderly patients who underwent a thoracic surgical procedure.

METHODS

A total of 90 patients aged 65 to 80 years old who underwent a thoracic surgical procedure at our hospital and 15 nonsurgical participants as controls, were enrolled in this study. Patients were divided in a randomized 1:1:1 ratio into 3 groups. All participants were randomized into a trial with three anesthesia groups (P, PS, PSD) or a control group (C) of healthy matches. All trial groups received distinct anesthetic combinations during surgery, while controls mirrored patient criteria.Group P (propofol and remifentanil were maintained during the surgery), Group PS (propofol, remifentanil, and sevoflurane were maintained during the surgery), and Group PSD (propofol, remifentanil, sevoflurane, and dexmedetomidine were maintained during the surgery).All participants were rated using a series of cognitive assessment scales before and three days after surgery. All participants were interviewed over the telephone, 7 days, 30 days, and 90 days postoperatively.

RESULTS

POCD incidences in the PSD (combined anesthetization with propofol, sevoflurane, and dexmedetomidine) group was significantly lower than that in the PS (combined anesthetization with propofol and sevoflurane) group, 1 day post-surgery (10.0% vs. 40.0%, P = 0.008), and the results were consistent at 3 days post-surgery. When the patients were assessed 7 days, 30 days, and 90 days postoperatively, there was no significant difference in POCD incidence among the three groups. Multivariate logistic regression analysis of POCD one day after surgery showed that education level was negatively correlated with incidence of POCD (P = 0.018) and single lung ventilation time was positively correlated with incidence of POCD (P = 0.001).

CONCLUSION

For elderly patients who underwent a thoracic surgical procedure, dexmedetomidine sedation shows an obvious advantage on improving short-term POCD incidence, which is caused by sevoflurane.

The Association of Cerebral Oxygen Desaturation with Postoperative Cognitive Dysfunction in Older Patients: A Review

Postoperative cognitive dysfunction (POCD) is a neurological complication associated with surgery and anesthesia that is commonly observed in older patients, and it can significantly affect patient prognosis and survival. Therefore, predicting and preventing POCD is important. Regional cerebral oxygen saturation (rSO2) reflects cerebral perfusion and oxygenation, and decreased intraoperative cerebral oxygen saturation has been reported to increase the risk of POCD. In this review, we elucidated the important relationship between the decline in rSO2 and risk of POCD in older patients. We also emphasized the importance of monitoring rSO2 during surgery to predict and prevent adverse perioperative cognitive outcomes. The findings reveal that incorporating intraoperative rSO2 monitoring into clinical practice has potential benefits, such as protecting cognitive function, reducing perioperative adverse outcomes, and ultimately improving the overall quality of life of older adults.

Cerebrovascular dysregulation and postoperative cognitive alterations after carotid endarterectomy

There are controversial data about the effect of carotid endarterectomy regarding postoperative cognitive function. Our aim was to analyze the effect of cerebral tissue saturation monitored by near-infrared spectroscopy (NIRS) on cognitive function. Perioperative data of 103 asymptomatic patients undergoing elective carotid surgery under general anesthesia were analyzed. Preoperatively and 3 months after the operation, MMSE (Mini Mental State Examination) and MoCA (Montreal Cognitive Assessment) tests were conducted. For cerebral monitoring, NIRS was used, and the lowest rSO2 value and the degree of desaturation were calculated. Cognitive changes were defined as one standard deviation change from the preoperative test scores, defined as postoperative neurocognitive decline (PNCD) and cognitive improvement (POCI). PNCD was found in 37 patients (35.92%), and POCI was found in 18 patients (17.47%). Female gender, patients with diabetes, and the degree of desaturation were independently associated with PNCD. The degree of desaturation during the cross-clamp period negatively correlated with the change in the MoCA scores (R =  - 0.707, p = 0.001). The 15.5% desaturation ratio had 86.5% sensitivity and 78.8% specificity for discrimination. For POCI, a desaturation of less than 12.65% had 72.2% sensitivity and 67.1% specificity. POCI was associated with lower preoperative MOCA scores and a lower degree of desaturation. We found a significant relation between the change of postoperative cognitive function proven by the MoCA test and cerebral tissue saturation during the clamping period in patients undergoing carotid endarterectomy.

Comparison of analgesic effect of pericapsular nerve group block and supra-inguinal fascia iliaca compartment block on dynamic pain in patients with hip fractures: a randomized controlled trial

BACKGROUND

Patients with hip fracture often experience severe pain, particularly during movement or slight positional change, prior to the occurrence of surgery. It is essential to explore the appropriate analgesic methods before surgery in patients with hip fracture, especially those capable of alleviating dynamic pain. Pericapsular nerve group (PENG) block was introduced as a useful technique for hip analgesia. In this study, we aimed to compare the reduction in dynamic pain between the PENG block and supra-inguinal fascia iliaca compartment block (SIFICB).

METHODS

This prospective trial included 80 hip fracture patients aged ≥19 years, with an American Society of Anesthesiologists Physical Status of 1-4 and a baseline dynamic pain score ≥4 on the numerical rating scale. The patients were randomly allocated into the PENG block (n=40) and SIFICB group (n=40). For the PENG block and SIFICB, 20 mL and 30 mL of 0.3% ropivacaine was used, respectively. The primary outcome was reduction in dynamic pain scores at 30 min following the peripheral nerve block. Dynamic pain score was evaluated when the leg was passively raised.

RESULTS

A total of 79 patients were included in the final analysis, and the reductions in pain score during hip flexion were 3.1±2.4 and 2.9±2.5 in the PENG block and SIFICB groups, respectively, which was statistically insignificant (p=0.75). Moreover, no significant differences were observed in any of the outcomes.

CONCLUSIONS

PENG block and SIFICB could effectively provide analgesia for dynamic pain in patients with hip fractures, with no significant difference between the two groups.

TRIAL REGISTRATION NUMBER

NCT04677348.

Deciphering the dual role of N-methyl-D-Aspartate receptor in postoperative cognitive dysfunction: A comprehensive review

Postoperative cognitive dysfunction (POCD) is a common complication following surgery, adversely impacting patients' recovery, increasing the risk of negative outcomes, prolonged hospitalization, and higher mortality rates. The N-methyl-D-aspartate (NMDA) receptor, crucial for learning, memory, and synaptic plasticity, plays a significant role in the development of POCD. Various perioperative factors, including age and anesthetic use, can reduce NMDA receptor function, while surgical stress, inflammation, and pain may lead to its excessive activation. This review consolidates preclinical and clinical research to explore the intricate relationship between perioperative factors affecting NMDA receptor functionality and the onset of POCD. It discusses the influence of aging, anesthetic administration, perioperative injury, pain, and inflammation on the NMDA receptor-related pathophysiology of POCD. The comprehensive analysis presented aims to identify effective treatment targets for POCD, contributing to the improvement of patient outcomes post-surgery.

Two-lung ventilation with artificial pneumothorax on cerebral desaturation and early postoperative cognitive outcome: a randomized controlled trial

BACKGROUND

The effect of two lung ventilation (TLV) with carbon dioxide artificial pneumothorax on cerebral desaturation and postoperative neurocognitive changes in elderly patients undergoing elective minimally invasive esophagectomy (MIE) is unclear.

OBJECTIVES

The first aim of this study was to compare the effect of TLV and one lung ventilation (OLV) on cerebral desaturation. The second aim was to assess changes in early postoperative cognitive outcomes of two ventilation methods.

METHODS

This prospective, randomized, controlled trial enrolled patients 65 and older scheduled for MIE. Patients were randomly assigned (1:1) to TLV group or OLV group. The primary outcome was the incidence of cerebral desaturation events (CDE). Secondary outcomes were the cumulative area under the curve of desaturation for decreases in regional cerebral oxygen saturation (rSO2) values below 20% relative to the baseline value (AUC.20) and the incidence of delayed neurocognitive recovery.

RESULTS

Fifty-six patients were recruited between November 2019 and August 2020. TLV group had a lower incidence of CDE than OLV group [3 (10.71%) vs. 13 (48.14%), P = 0.002]. TLV group had a lower AUC.20 [0 (0-35.86) % min vs. 0 (0-0) % min, P = 0.007], and the incidence of delayed neurocognitive recovery [2 (7.4%) vs. 11 (40.7%), P = 0.009] than OLV group. Predictors of delayed neurocognitive recovery on postoperative day 7 were age (OR 1.676, 95% CI 1.122 to 2.505, P = 0.006) and AUC.20 (OR 1.059, 95% CI 1.025 to 1.094, P < 0.001).

CONCLUSION

Compared to OLV, TLV had a lower incidence of CDE and delayed neurocognitive recovery in elderly patients undergoing MIE. The method of TLV combined with carbon dioxide artificial pneumothorax may be an option for these elderly patients. Chinese Clinical Trial Registry (identifier: ChiCTR1900027454).

Effects of positive end-expiratory pressure on regional cerebral oxygen saturation in elderly patients undergoing thoracic surgery during one-lung ventilation: a randomized crossover-controlled trial

BACKGROUND

A significant reduction in regional cerebral oxygen saturation (rSO2) is commonly observed during one-lung ventilation (OLV), while positive end-expiratory pressure (PEEP) can improve oxygenation. We compared the effects of three different PEEP levels on rSO2, pulmonary oxygenation, and hemodynamics during OLV.

METHODS

Forty-three elderly patients who underwent thoracoscopic lobectomy were randomly assigned to one of six PEEP combinations which used a crossover design of 3 levels of PEEP-0 cmH2O, 5 cmH2O, and 10 cmH2O. The primary endpoint was rSO2 in patients receiving OLV 20 min after adjusting the PEEP. The secondary outcomes included hemodynamic and respiratory variables.

RESULTS

After exclusion, thirty-six patients (36.11% female; age range: 60-76 year) were assigned to six groups (n = 6 in each group). The rSO2 was highest at OLV(0) than at OLV(10) (difference, 2.889%; [95% CI, 0.573 to 5.204%]; p = 0.008). Arterial oxygen partial pressure (PaO2) was lowest at OLV(0) compared with OLV(5) (difference, -62.639 mmHg; [95% CI, -106.170 to -19.108 mmHg]; p = 0.005) or OLV(10) (difference, -73.389 mmHg; [95% CI, -117.852 to -28.925 mmHg]; p = 0.001), while peak airway pressure (Ppeak) was lower at OLV(0) (difference, -4.222 mmHg; [95% CI, -5.140 to -3.304 mmHg]; p < 0.001) and OLV(5) (difference, -3.139 mmHg; [95% CI, -4.110 to -2.167 mmHg]; p < 0.001) than at OLV(10).

CONCLUSIONS

PEEP with 10 cmH2O makes rSO2 decrease compared with 0 cmH2O. Applying PEEP with 5 cmH2O during OLV in elderly patients can improve oxygenation and maintain high rSO2 levels, without significantly increasing peak airway pressure compared to not using PEEP.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200060112 on 19 May 2022.

The Effect of Ciprofol on Postoperative Delirium in Elderly Patients Undergoing Thoracoscopic Surgery for Lung Cancer: A Prospective, Randomized, Controlled Trial

Purpose

This study was conducted to assess whether ciprofol vs propofol could affect the incidence of postoperative delirium (POD) in elderly patients with lung cancer after thoracoscopic surgery.

Patients and Methods

In this study, a total of 84 elderly patients undergoing thoracoscopic surgery for lung cancer were recruited and randomized into two groups to receive anesthesia with either ciprofol or propofol. The primary outcome was the incidence of POD within three days after surgery. Secondary outcomes included the Confusion Assessment Method (CAM) score, intraoperative indicators related to mean arterial pressure (MAP), and cerebral tissue oxygen saturation (SctO2). Moreover, MAP- and SctO2-related indicators associated with POD were analyzed.

Results

The incidence of POD was 7.1% and 16.7%, respectively, in the ciprofol group and the propofol group (risk ratio [RR], 0.37; 95% confidence interval [CI], 0.07 to 2.03; risk difference [RD], -9.6%; 95% CI, -23.3% to 4.1%; p = 0.178). Compared with those in the propofol group, patients in the ciprofol group had lower CAM scores three days after surgery (13 (12, 15) vs 15 (14, 17); 12 (11, 13) vs 14 (13, 16); 12 (11, 12) vs 13 (12, 14), p<0.05). Besides, patients in the ciprofol group exhibited higher mean and minimum MAP (88.63 ± 6.7 vs 85 ± 8.3; 69.81 ± 9.59 vs 64.9 ± 9.43, p<0.05) and SctO2 (77.26 ± 3.96 vs 75.3 ± 4.49, 71.69 ± 4.51 vs 68.77 ± 6.46, p<0.05) and percentage of time for blood pressure stabilization (0.6 ± 0.14 vs 0.45 ± 0.14, p<0.05) than those in the propofol group. Furthermore, MAP and SctO2-related indicators were validated to correlate with POD.

Conclusion

Anesthesia with ciprofol did not increase the incidence of POD compared with propofol. The results demonstrated that ciprofol could improve intraoperative MAP and SctO2 levels and diminish postoperative CAM scores.

Effects of nonintubated thoracoscopic surgery on postoperative neurocognitive function: a randomized controlled trial

OBJECTIVES

Postoperative neurocognitive disorder following thoracoscopic surgery with general anaesthesia may be linked to reduced intraoperative cerebral oxygenation and perioperative inflammation, which can potentially be exacerbated by mechanical ventilation. However, nonintubated thoracoscopic surgery, which utilizes regional anaesthesia and maintains spontaneous breathing, provides a unique model for studying the potential benefits of avoiding mechanical ventilation. This approach allows investigation into the impact on perioperative neurocognitive profiles, inflammatory responses and intraoperative cerebral oxygen levels.

METHODS

In total, 110 patients undergoing thoracoscopic surgery were randomly equally assigned to the intubated group and the nonintubated group. Regional cerebral oxygenation was monitored during surgery. Serum neuroinflammatory biomarkers, including interleukin-6 and glial fibrillary acidic protein, were measured at baseline (before surgery) and 24 h after surgery. Postoperative complication severity was compared using the Comprehensive Complication Index. The primary outcome was perioperative changes in neurocognitive test score, which was assessed at baseline, 24 h and 6 months after surgery.

RESULTS

Patients in the nonintubated group had higher neurocognitive test scores at 24 h (69.9 ± 10.5 vs 65.3 ± 11.8; P = 0.03) and 6 months (70.6 ± 6.7 vs 65.4 ± 8.1; P < 0.01) after surgery and significantly higher regional cerebral oxygenation over time during one-lung ventilation (P = 0.03). Patients in the intubated group revealed a significantly higher postoperative serum interleukin-6 level (group by time interaction, P = 0.04) and a trend towards a significantly higher serum glial fibrillary acidic protein level (group by time interaction, P = 0.11). Furthermore, patients in the nonintubated group had a significantly lower Comprehensive Complication Index (9.0 ± 8.2 vs 6.1 ± 7.1; P < 0.05).

CONCLUSIONS

Nonintubated thoracoscopic surgery was associated with improved postoperative neurocognitive recovery, more stable intraoperative cerebral oxygenation, ameliorated perioperative inflammation and attenuated postoperative complication severity.

Propofol Versus Remimazolam on Cognitive Function, Hemodynamics, and Oxygenation During One-Lung Ventilation in Older Patients Undergoing Pulmonary Lobectomy: A Randomized Controlled Trial

OBJECTIVES

To investigate the effects of remimazolam on postoperative cognitive function, intraoperative hemodynamics, and oxygenation in older patients undergoing lobectomy.

DESIGN

A prospective, double-blind, randomized, controlled study.

SETTING

A university hospital.

PARTICIPANTS

Eighty-four older patients with lung cancer who underwent lobectomy, aged ≥65 years.

INTERVENTIONS

Patients were divided randomly into the remimazolam (group R) and propofol (group P) groups. Group R underwent remimazolam anesthesia induction and maintenance, whereas group P underwent propofol anesthesia induction and maintenance. Cognitive function was assessed with neuropsychological tests 1 day before surgery and 7 days after surgery. The Clock Drawing Test, Verbal Fluency Test (VFT), Digit Symbol Switching Test (DSST), and Auditory Verbal Learning Test-Huashan (AVLT-H) assessed visuospatial ability, language function, attention, and memory, respectively. The systolic blood pressure (SBP), heart rate, mean arterial pressure (MAP), and cardiac index were recorded 5 minutes before induction of anesthesia (T0), 2 minutes after sedation (T1), 5 minutes after intubation with two-lung ventilation (T2), 30 minutes after one-lung ventilation (OLV) (T3), 60 minutes after OLV (T4), and at the end of surgery (T5), and the incidences of hypotension and bradycardia were recorded. The PaO2, oxygenation index (OI), and intrapulmonary shunt (Qs/Qt) were assessed at T0, T2, T3, T4, and T5. The levels of S-100β and interleukin 6 were measured by enzyme-linked immunosorbent assay at T0, T5, 24 hours after surgery (T6), and on day 7 after surgery (T7).

MEASUREMENTS AND MAIN RESULTS

The VFT, DSST, immediate recall AVLT-H, and short-delayed recall AVLT-H scores were significantly higher in group R than in group P on day 7 after surgery (p < 0.05). The SBP and MAP at T2 to T5 were significantly higher in group R than in group P, the incidence of hypotension was significantly lower in group R (9.5%) than in group P (35.7%) (p = 0.004), and remimazolam significantly reduced the dose of phenylephrine used (p < 0.05). The PaO2 and OI at T4 were significantly higher in group R than in group P, and Qs/Qt was significantly lower in group R than in group P. The levels of S-100β at T5 were significantly lower in group R than in group P (p < 0.05).

CONCLUSION

The results showed that remimazolam (versus propofol) may lessen the degree of short-term postoperative cognitive dysfunction measured by standard neuropsychological tests, better optimize intraoperative hemodynamics, and lead to improved oxygenation during OLV.

Dose-dependent relationship between intra-procedural hypoxaemia or hypocapnia and postoperative delirium in older patients

BACKGROUND

Previous studies indicated an association between impaired cerebral perfusion and post-procedural neurological disorders. We investigated whether intra-procedural hypoxaemia or hypocapnia are associated with delirium after surgery.

METHODS

Inpatients ≥60 yr of age undergoing anaesthesia for surgical or interventional procedures between 2009 and 2020 at an academic healthcare network in the USA (Massachusetts) were included in this hospital registry study. The primary exposure was intra-procedural hypoxaemia, defined as peripheral oxygen saturation <90% for >2 cohering min. The co-primary exposure was hypocapnia during general anaesthesia, defined as end-tidal carbon dioxide pressure ≤25 mm Hg for >5 cohering min. The primary outcome was delirium within 7 days after surgery.

RESULTS

Of 71 717 included patients, 1702 (2.4%) developed postoperative delirium, and hypoxaemia was detected in 2532 (3.5%). Of 42 894 patients undergoing general anaesthesia, 532 (1.2%) experienced hypocapnia. The occurrence of either hypoxaemia (adjusted odds ratio [OR_adj]=1.71; 95% confidence interval [CI], 1.40-2.07; P<0.001) or hypocapnia (OR_adj=1.77; 95% CI, 1.30-2.41; P<0.001) was associated with a higher risk of delirium within 7 days. Both associations were dependent on the magnitude, and increased with event duration (OR_adj=1.03; 95% CI, 1.02-1.04; P<0.001 and OR_adj=1.01; 95% CI, 1.00-1.01; P=0.005, for each minute increase in the longest continuous episode, respectively). There was no association between occurrence of hypercapnia and postoperative delirium (OR_adj=1.24; 95% CI, 0.90-1.71; P=0.181).

CONCLUSIONS

Intra-procedural hypoxaemia and hypocapnia were dose-dependently associated with a higher risk of postoperative delirium. These findings support maintaining normal gas exchange to avoid postoperative neurological disorders.

Evaluation of the relationship between intraoperative cerebral oxygen saturation and postoperative cognitive functions in laparoscopic hysterectomy surgery

Objective: Laparoscopic surgery has become more popular than traditional open surgery because it is less invasive, provides faster recovery, and provides better cosmetic success. This procedure requires insufflation of an inert gas into the peritoneal cavity. This may be an increase in arterial CO2, changes in cerebral blood flow, an increase in intra-abdominal pressure (IAP), a decrease in cardiac output. The primary outcome of this study is to show the effect of IAP levels on cerebral oxygen saturation (COS) in patients who underwent laparoscopic total abdominal hysterectomy, and the secondary outcome is to reveal the relationship between IAP and COS and the recovery of postoperative cognitive functions. Material and Method: Demographic data of the cases were recorded and mini-mental test (MMT) was applied to evaluate the preoperative cognitive functions of the cases before surgery. COS monitoring were performed with standard anesthesia procedure for all patients. The MMT was repeated after the surgery. Results: A total of 40 female patients were included in the study. Those with IAP level 12 and below were defined as Group Low-Pressure, and those above 12 were defined as Group High-Pressure. There was no statistical difference between the anesthesia times and recovery times of the two groups. While there was no statistical difference in the preoperative MMT evaluation, it was found to be significantly lower in Group H in the postoperative MMT evaluation. Conclusion: In this study, we evaluated the effect of intraoperative IAP levels on intraoperative COS. It is seen that high IAP level does not have a negative effect on COS. In addition, this study has evidence that high IAP affects postoperative cognitive functions. In intraoperative management for TLH surgery, we recommend maintaining the IAP level at the lowest appropriate pressure that does not impair surgical comfort.

Comparison of regional cerebral oxygen saturation during one-lung ventilation under desflurane or propofol anesthesia: A randomized trial

BACKGROUND

During one-lung ventilation (OLV), deterioration of pulmonary oxygenation reduces arterial oxygen saturation and cerebral oxygen saturation (rSO2). However, oxidative stress during OLV causes lung injury, so the fraction of inspiratory oxygen (FiO2) should be kept as low as possible. We investigated the changes in rSO2 under propofol or desflurane anesthesia while percutaneous oxygen saturation (SpO2) was kept as low as possible during OLV.

METHODS

Thirty-six patients scheduled for thoracic surgery under OLV in the lateral decubitus position were randomly assigned to propofol (n = 19) or desflurane (n = 17) anesthesia. FiO2 was set to 0.4 at the start of surgery under two-lung ventilation (measurement point: T3) and then adjusted to maintain an SpO2 of 92% to 94% after the initiation of OLV. The primary outcome was the difference in the absolute value of the decrease in rSO2 from T3 to 30 minutes after the initiation of OLV (T5), which was analyzed by an analysis of covariance adjusted for the rSO2 value at T3.

RESULTS

The mean rSO2 values were 61.5% ± 5.1% at T3 and 57.1% ± 5.3% at T5 in the propofol group and 62.2% ± 6.0% at T3 and 58.6% ± 5.3% at T5 in the desflurane group. The difference in the absolute value of decrease between groups (propofol group - desflurane group) was 0.95 (95% confidence interval, [-0.32, 2.2]; P = .152).

CONCLUSIONS

Both propofol and desflurane anesthesia maintain comparable cerebral oxygenation and can be used safely, even when the SpO2 is kept as low as possible during OLV.

Effect of dexmedetomidine on the Montreal Cognitive Assessment in older patients undergoing pulmonary surgery

Objective

We investigated the effect of dexmedetomidine anesthesia on postoperative cognitive function after pulmonary surgery.

Methods

A blinded, prospective, randomized, placebo-controlled study was performed on 60 patients (age range 65–74 years) undergoing lobectomy by video-assisted thoracoscopic surgery (29 in the dexmedetomidine group; 31 in the placebo group). Dexmedetomidine group patients received dexmedetomidine, and placebo group patients received an equal volume of physiological saline 20 minutes before anesthesia induction. Cognitive function was evaluated using the Montreal Cognitive Assessment 1 day before surgery and on postoperative day (POD)1, POD3, and POD7. The regional cerebral oxygen saturation (rSO₂) was monitored continuously by near-infrared spectroscopy before anesthesia.

Results

The Montreal Cognitive Assessment score was significantly different between the two groups on POD1 (dexmedetomidine 26.4  ±  0.73 vs. placebo 25.5 ± 0.96) and POD3 (dexmedetomidine 27.1 ± 0.79 vs. placebo 26.6 ± 0.80). Specifically, attention and orientation scores were increased in the dexmedetomidine group on POD1 and POD3. The rSO₂ was not significantly different between the dexmedetomidine and placebo groups.

Conclusion

Dexmedetomidine given before induction of anesthesia could reduce the risk of postoperative cognitive dysfunction and might not decrease rSO₂. Hence, dexmedetomidine could be employed in pulmonary surgical procedures, especially for older patients with a high risk of cognitive dysfunction.

Intelligent Algorithm-Based Echocardiography to Evaluate the Effect of Lung Protective Ventilation Strategy on Cardiac Function and Hemodynamics in Patients Undergoing Laparoscopic Surgery

The aim of this study was to analyze the effect of optimal pulmonary compliance titration of PEEP regimen on cardiac function and hemodynamics in patients undergoing laparoscopic surgery. 120 patients undergoing elective laparoscopic radical resection of colorectal cancer were included as the study subjects and randomly divided into the experimental group (n = 60) and the control group (n = 60). The control group had a fixed positive end-expiratory pressure (PEEP) = 5 cmH2O. The experimental group had transesophageal ultrasound monitoring through on an improved noise reduction algorithm (ONLM) based on nonlocal mean filtering (NLM) according to optimal pulmonary compliance titration of PEEP. There was significant difference in cerebral oxygen saturation and blood glucose level at T4-T6 between the experimental group and the control group (P < 0.05); the signal-to-noise ratio (SNR), figure of merit (FOM), and structural similarity (SSIM) of ONLM algorithm were significantly higher than those of NLM algorithm and Bayes Shrink denoising algorithm, and the differences were statistically significant (P < 0.05); there was significant difference in stroke volume (SV) and cardiac output (CO) at T4-T6 between the experimental group and the control group (P < 0.05); there was significant difference in pH, partial pressure of carbon dioxide (PCO2), and PO2 at T4-T6 between the experimental group and the control group (P < 0.05); pH was higher, and PCO2 and PO2 were lower in the experimental group. The results showed that transesophageal ultrasound based on the ONLM algorithm can accurately assess cardiac function and hemodynamics in patients undergoing laparoscopic surgery. In addition, optimal pulmonary compliance titration of PEEP could better maintain arterial acid-base balance during perioperative period and increase cerebral oxygen saturation and CO, but this strategy had no significant effect on hemodynamics.

Monocyte NLRP3-IL-1β Hyperactivation Mediates Neuronal and Synaptic Dysfunction in Perioperative Neurocognitive Disorder

Perioperative neurocognitive disorder may develop in vulnerable patients following major operation. While neuroinflammation is linked to the cognitive effects of surgery, how surgery and immune signaling modulate neuronal circuits, leading to learning and memory impairment remains unknown. Using in vivo two-photon microscopy, Ca2+ activity and postsynaptic dendritic spines of layer 5 pyramidal neurons in the primary motor cortex of a mouse model of thoracic surgery are imaged. It is found that surgery causes neuronal hypoactivity, impairments in learning-dependent dendritic spine formation, and deficits in multiple learning tasks. These neuronal and synaptic alterations in the cortex are mediated by peripheral monocytes through the NLRP3 inflammasome-dependent IL-1β production. Depleting peripheral monocytes or inactivating NLRP3 inflammasomes before surgery reduces levels of IL-1β and ameliorates neuronal and behavioral deficits in mice. Furthermore, adoptive transfer of IL-1β-producing myeloid cells from mice undertaking thoracic surgery is sufficient to induce neuronal and behavioral deficits in naïve mice. Together, these findings suggest that surgery leads to excessive NLRP3 activation in monocytes and elevated IL-1β signaling, which in turn causes neuronal hypoactivity and perioperative neurocognitive disorder.

Dexmedetomidine improved one-lung ventilation-induced cognitive dysfunction in rats

BACKGROUND

One-lung ventilation (OLV) is widely used in thoracic surgery. However, OLV may also increase CERO₂ and aggravate delayed cognitive recovery. Here, we aimed to investigate the effect of dexmedetomidine (DEX) on cognitive function in rats undergoing OLV.

METHODS

Sprague-Dawley rats were randomly divided into two-lung ventilation (TLV) group, OLV group and OLV treated with DEX group. Group DEX received 25 μg/kg DEX i.p. 30 min before induction. After mechanical ventilation (MV), Morris water maze (MWM) test was carried out to examine spatial memory function. Western blotting was used to detect pERK1/2, pCREB, Bcl-2 and BAX in hippocampal tissues. Transmission electron microscopy (TEM) was used to observe the hippocampal CA1 region.

RESULTS

Post-MV, compared with group OLV, group DEX showed increases in percentage of target quadrant time (P < 0.05), platform crossings (P < 0.05), a reduction in CERO₂ (P < 0.05), and pERK1/2, pCREB, and Bcl-2 significantly increased (P < 0.01 or P < 0.05), while BAX significantly decreased (P < 0.01), besides, a less damaged synaptic structure was observed in group DEX.

CONCLUSIONS

DEX improved post-MV cognitive function in rats undergoing OLV, reduced cerebral oxygen consumption, protected synaptic structure and upregulated ERK1/2-CREB anti-apoptotic signaling pathway in hippocampal CA1 region.

Flurbiprofen used in one-lung ventilation improves intraoperative regional cerebral oxygen saturation and reduces the incidence of postoperative delirium

BACKGROUND

We previously demonstrated that flurbiprofen increased arterial oxygen partial pressure and reduced intrapulmonary shunts. The present study aims to investigate whether flurbiprofen improves intraoperative regional cerebral oxygen saturation (rScO₂) and reduces the incidence of postoperative delirium (POD) in elderly patients undergoing one-lung ventilation (OLV).

METHODS

One hundred and twenty patients undergoing thoracoscopic lobectomy were randomly assigned to the flurbiprofen-treated group (n = 60) and the control-treated group (n = 60). Flurbiprofen was intravenously administered 20 minutes before skin incision. The rScO₂ and partial pressure of arterial oxygen (PaO₂) were recorded during the surgery, and POD was measured by the Confusion Assessment Method (CAM) within 5 days after surgery. The study was registered in the Chinese Clinical Trial Registry with the number ChiCTR1800020032.

RESULTS

Compared with the control group, treatment with flurbiprofen significantly improved the mean value of intraoperative rScO₂ as well as the PaO₂ value (P < 0.05, both) and significantly reduced the baseline values of the rScO₂ area under threshold (AUT) (P < 0.01) at 15, 30, and 60 min after OLV in the flurbiprofen-treated group. After surgery, the POD incidence in the flurbiprofen-treated group was significantly decreased compared with that in the control group (P < 0.05).

CONCLUSION

Treatment with flurbiprofen may improve rScO₂ and reduce the incidence of POD in elderly patients undergoing thoracoscopic one-lung ventilation surgery for lung cancer.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org/cn/, identifier ChiCTR1800020032.

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.

Role of Dexmedetomidine in Early POCD in Patients Undergoing Thoracic Surgery

Objective

To evaluate whether a low-dose perioperative infusion of Dex reduces early POCD.

Design

This study was a double-blind, randomized, placebo-controlled trial that randomly assigned patients to Dex or saline placebo infused during surgery and patient-controlled intravenous analgesia (PCIA) infusion. Patients were assessed for postoperative cognitive decline. Interventions. Dex was infused at a loading dose of 0.5 μg/kg intravenously (15 min after entering the operation room) followed by a continuous infusion at a rate of 0.5 μg/kg/h until one-lung ventilation or artificial pneumothorax ended. Patients in the Dex group received regular PCIA pump with additional dose of Dex (200 μg).

Results

In total, 126 patients were randomized, and 102 patients were involved in the result analysis. The incidence of POCD was 36.54% (19/52) in the Dex group and 32.00% (16/50) in the normal saline (NS) group, with no statistic difference. No significant difference was observed between the two groups in terms of Telephone Interview for Cognitive Status-Modified (TICS-m) scores at different times. However, the TICS-m score at 7 days after surgery was significantly lower than that at 30 days in 102 patients (32.93 ± 0.42 vs. 33.92 ± 0.47, P = 0.03). The visual analogue scale scores in the Dex group were significantly lower than those in the NS group 1 day postoperation at rest and activity (2.00 [1.00-3.00] vs. 3.00 [2.00-4.00], P < 0.01; 4.00 [3.00-5.00] vs. 5.00 [4.00-6.00], P < 0.05, respectively). Patients receiving Dex or NS had no statistical difference in activities of daily living (ADLs) scores at 7 and 30 days after surgery, but the ADL score at 30 days after surgery showed a significant reduction compared with that at 7 days (P < 0.01). Patients in the Dex group had a shorter hospital length of stay (15.26 ± 3.77 vs. 17.69 ± 5.09, P = 0.02) and less expenses (52458.71 ± 10649.30 vs. 57269.03 ± 9269.98, P = 0.04) than those in the NS group.

Conclusions

Low-dose Dex in the perioperative period did not reduce the incidence of early POCD in thoracic surgery. However, it relieved postoperative pain, decreased the hospitalization expenses, and shortened the length of stay.

Effect of desflurane on changes in regional cerebral oxygenation in patients undergoing one-lung ventilation is equivalent to the effect of propofol

OBJECTIVES

Desaturation is an important clinical problem during one-lung ventilation (OLV) since it may induce cerebral hypoxia. Measurement of cerebral oxygenation has been shown to provide accurate information about episodes of cerebral hypoxemia. The purpose of this study was to compare the effect of desflurane on changes in cerebral oxygenation during OLV with the effect of propofol.

METHODS

A randomized, single-blinded, prospective study was conducted. Fifty adult patients who were scheduled to undergo thoracic surgery were randomly assigned to anesthetic management using desflurane with remifentanil (Group D: n = 25) or using propofol and remifentanil (Group P: n = 25).

RESULTS

The characteristics of the patients were very similar. Intergroup analysis of changes in cerebral oxygenation showed no significant difference on the operative side (two-way ANOVA, F (7, 368) = 0.425, p = 0.887) or the non-operative side (two-way ANOVA, F (7, 367) = 1.342, p = 0.229). Intragroup analysis of changes in cerebral oxygenation using one-way ANOVA showed no significant difference on the operative side (Group P; p = 0.585, Group D; p = 0.928) or the non-operative side in both groups (Group P; p = 0.657, Group D; p = 0.602).

CONCLUSIONS

The effects of desflurane and propofol on changes in cerebral oxygenation in patients undergoing OLV were equivalent. Our results indicated that desflurane might be an appropriate anesthetic during OLV for maintaining cerebral oxygenation with an effective equivalent to that of propofol.

Near-Infrared Spectroscopy (NIRS) for Cerebral and Tissue Oximetry: Analysis of Evolving Applications

THE USE OF NEAR-INFRARED SPECTROSCOPY (NIRS) has increased significantly worldwide in the past decade. This technology, first described more than 40 years ago, is based on the fact that near-infrared light is able to penetrate biologic tissue and can obtain real-time, noninvasive information on tissue oxygenation and metabolism. In the clinical setting, NIRS has been able to provide clinicians potentially valuable information in patients with impaired microcirculations (systemic and cerebral). Near-infrared spectroscopy has progressed beyond assessment of brain oxygenation to monitor local tissue and muscle oxygenation and perfusion. This review analyzes the published data and provides the clinician a comprehensive account of the perioperative utility of NIRS in cardiac, vascular and thoracic surgery, as well as its increasing role in tissue/muscle oxygenation monitoring.

Intraoperative Oxygen Concentration and Postoperative Delirium After Laparoscopic Gastric and Colorectal Malignancies Surgery: A Randomized, Double-Blind, Controlled Trial

Purpose

Postoperative delirium (POD) is common in elderly patients undergoing laparoscopic surgery for gastric and colorectal malignancies. POD may be affected by different fraction of inspired oxygen (FiO₂). The purpose of this study was to compare the effects of different FiO₂ on POD.

Patients and Methods

A randomized, double-blind controlled trial was performed in Qingdao Municipal Hospital Affiliated to Qingdao University. A total of 662 patients aged 65 to 85 years old underwent isolated laparoscopic radical gastrectomy, radical resection of colon cancer, or radical resection of rectal cancer only. A random number table method was used to divide the patients into two groups: 40% FiO₂ (group A) and 80% FiO₂ (group B). The primary endpoint was the incidence of POD, which was assessed by the Confusion Assessment Method (CAM) twice daily during the first 7 postoperative days, and POD severity was measured by the Memorial Delirium Assessment Scale (MDAS). The secondary endpoints were the intraoperative regional cerebral oxygen saturation (rSO₂), Bispectral (BIS) index, invasive arterial blood pressure (IABP), oxygen saturation (SpO₂), end-tidal carbon dioxide partial pressure (P_ETCO₂), the number of atelectasis cases and visual analogue scale (VAS) scores on days 1-7 after surgery.

Results

The incidence of POD was 19.37% (122/630), including 20.38% (64/314) in group A and 18.35% (58/316) in group B. No statistical significance was found in the incidence of POD between the two groups (P > 0.05); compared with group B, SpO₂, rSO₂ and PaO₂ decreased at T₂ to T₄ time point (P < 0.01), and the incidence of postoperative atelectasis decreased (P < 0.05) in group A.

Conclusion

The incidence of POD was not significantly affected by different FiO₂ and the incidence of postoperative atelectasis was decreased at low FiO₂.

The Potential Role of Lung-Protective Ventilation in Preventing Postoperative Delirium in Elderly Patients Undergoing Prone Spinal Surgery: A Preliminary Study

Background

Postoperative delirium (POD) is a frequent complication in elderly patients, usually occurring within a few days after surgery. This study investigated the effect of lung-protective ventilation (LPV) on POD in elderly patients undergoing spinal surgery and the mechanism by which LPV suppresses POD.

Material/Methods

Seventy-one patients aged ≥65 years were randomized to receive LPV or conventional mechanical ventilation (MV), consisting of intermittent positive pressure ventilation following induction of anesthesia. The tidal volume in patients who received MV was 8 ml/kg predicted body weight (PBW), and the ventilation frequency was 12 times/min. The tidal volume in patients who received LPV was 6 ml/kg PBW, the positive end-expiratory pressure was 5 cmH₂O, and the ventilation frequency was 15 times/min, with a lung recruitment maneuver performed every 30 min. Blood samples were collected immediately before anesthesia induction (T₀), 10 min (T₁) and 60 min (T₂) after turning over, immediately after the operation (T₃), and 15 min after extubation (T₄) for blood gas analysis. Simultaneous cerebral oxygen saturation (rSO₂) and cerebral desaturation were recorded. Preoperative and postoperative serum concentrations of interleukin (IL)-6, IL-10 and glial fibrillary acidic protein (GFAP) were measured by ELISA. POD was assessed by nursing delirium screening score.

Results

Compared with the MV group, pH was lower and PaCO₂ higher in the LPV group at T₂. In addition PaO₂, SaO₂, and PaO₂/FiO₂ were higher at T₁, and T₄, and rSO₂ was higher at T₃, and T₄ in the LPV than in the MV group (P<0.05 each). Postoperative serum GFAP and IL-6 were lower and IL-10 higher in the LPV group. The incidences of cerebral desaturation and POD were significantly lower in the LPV group (P<0.05).

Conclusions

LPV may reduce POD in elderly patients undergoing spinal surgery by inhibiting inflammation and improving cerebral oxygen metabolism.

The Association of Cerebral Desaturation During One-Lung Ventilation and Postoperative Recovery: A Prospective Observational Cohort Study

OBJECTIVES

This study was designed to investigate whether cerebral oxygen desaturations during thoracic surgery are predictive of patients' quality of recovery. As a secondary aim, the authors investigated the relationship among cerebral desaturations and postoperative delirium and hospital length of stay.

DESIGN

This study was a prospective observational cohort study.

SETTING

A single tertiary-care medical center from September 2012 through March 2014.

PATIENTS

Adult patients scheduled for elective pulmonary surgery requiring one-lung ventilation.

INTERVENTIONS

All patients were monitored with the ForeSight cerebral oximeter.

MEASUREMENTS AND MAIN RESULTS

The primary assessment tool was the Postoperative Quality of Recovery Scale. Delirium was assessed using the Confusion Assessment Method. Of the 117 patients analyzed in the study, 60 of the patients desaturated below a cerebral oximetry level of 65% for a minimum of 3 minutes (51.3%). Patients who desaturated were significantly less likely to have cognitive recovery in the immediate postoperative period (p = 0.012), which did not persist in the postoperative period beyond day 0. Patients who desaturated also were more likely to have delirium (p = 0.048, odds ratio 2.81 [95% CI 1.01-7.79]) and longer length of stay (relative duration 1.35, 95% CI 1.05-1.73; p = 0.020).

CONCLUSIONS

Intraoperative cerebral oxygen desaturations, frequent during one-lung ventilation, are associated significantly with worse early cognitive recovery, high risk of postoperative delirium, and prolonged length of stay. Large interventional studies on cerebral oximetry in the thoracic operating room are warranted.

Intraoperative Anesthetic Management of the Thoracic Patient

The intraoperative anesthetic management for thoracic surgery can impact a patient's postoperative course, especially in patients with significant lung disease. One-lung ventilation poses an inherent risk to patients, including hypoxemia, acute lung injury, and right ventricular dysfunction. Patient-specific ventilator management strategies during one-lung ventilation can reduce postoperative morbidity.

Perioperative probiotic treatment decreased the incidence of postoperative cognitive impairment in elderly patients following non-cardiac surgery: A randomised double-blind and placebo-controlled trial

BACKGROUND

Given that population aging is a global health challenge, the high prevalence of postoperative neurocognitive impairment in elderly patients necessitates the development of novel simple and effective prevention methods.

OBJECTIVE

To evaluate the effects of perioperative application of oral probiotic as a prophylaxis for cognitive impairment in elderly patients following non-cardiac surgery.

METHODS

This randomised double-blind and placebo-controlled trial included 120 elderly patients (in a modified intention-to-treat analysis) scheduled for elective orthopaedic or colorectal surgery. Patients were assigned to receive either probiotics or a placebo from hospital admission until discharge. The primary endpoint was the incidence of postoperative cognitive impairment, defined as a decrease of ≥3 points in the Mini-Mental State Examination (MMSE) scores from admission baseline to the 7th day post-surgery. Secondary endpoints included changes in plasma interleukin-6 (IL-6) and cortisol, postoperative pain intensity, postoperative sleep quality, gastrointestinal function recovery, and faecal microbiota composition.

RESULTS

The incidence of postoperative cognitive impairment in the probiotic group was significantly lower than in the control group (3 of 59 patients [5.1%] vs. 10 of 61 patients [16.4%], P = 0.046). In addition, compared to pre-surgery, the levels of plasma IL-6 and cortisol in the probiotic group decreased more than in the control group 5-7 days after surgery (IL-6: -117.90 ± 49.15 vs. -14.93 ± 15.21, P = 0.044; cortisol: -158.70 ± 53.52 vs. 40.98 ± 72.48, P = 0.010). Relative abundance at the genus level in the faeces of the probiotic group also changed more than in that of the control group during the perioperative period. In contrast, postoperative pain intensity, sleep quality, and gastrointestinal function recovery did not differ significantly between the two groups.

CONCLUSION

Perioperative application of oral probiotic prevents postoperative cognitive impairment in elderly patients following non-cardiac surgery, possibly via the limitation of peripheral inflammation and the stress response.

CPAP Effects on Oxygen Delivery in One-Lung Ventilation During Minimally Invasive Surgical Ablation for Atrial Fibrillation in The Supine Position

OBJECTIVE

In minimally invasive surgical ablation for atrial fibrillation during video-assisted thoracoscopy surgery, one-lung ventilation (OLV) with a double- lumen tube is commonly employed. In contrast with the majority of thoracic procedures, the patient lies supine; thus, the protective effect of gravity is lost and intrapulmonary shunt remains high. To decrease intrapulmonary shunt and to increase oxygenation, many strategies are utilized: high inspiratory fraction of oxygen (F_IO₂), positive end-expiratory pressure on the ventilated lung, and continuous positive airway pressure (CPAP) on the deflated lung.

DESIGN

The authors performed a prospective, single- center, randomized study to evaluate the effect of additional CPAP in the nonventilated lung on oxygen delivery during surgical ablation for atrial fibrillation via video-assisted thoracoscopy in the supine position.

SETTING

University hospital Centro Cardiologico Monzino IRCCS, Milano, Italy.

PARTICIPANTS

Twenty-two patients scheduled for minimally invasive surgical ablation for atrial fibrillation.

INTERVENTIONS

The patients underwent pressure-controlled ventilation, adjusting inspiratory pressure to obtain a tidal volume of 7 mL/kg while keeping F_IO₂ constantly 1.0, a respiratory rate to maintain arterial partial pressure of carbon dioxide (PaCO₂) between 35 and 40 mmHg, and positive end-expiratory pressure of 5 cmH₂O. During OLV, inspiratory pressure was reduced to obtain a tidal volume of 5 mL/kg, maintaining F_IO₂ of 1.0, a respiratory rate to maintain PaCO₂ between 35 and 40 mmHg with capnothorax of 10 cmH₂O. The patients were then randomized into the CPAP group (CPAP 10 cmH₂0 on deflated lung) and NO CPAP group. Inotropic agents (dopamine or dobutamine) were used if cardiac index fell below 1.5 L/min/m².

MEASUREMENTS AND MAIN RESULTS

Twenty-two patients were enrolled, randomized, and completed the study. Median age was 62 years. The difference in arterial partial pressure of oxygen between the 2 groups was shy of significance, p = 0.16. Cardiac index progressively increased during OLV until the end of the procedure in both groups (p < 0.01) and was maintained above 1.5 mL/min/m² during the whole study time. Arterial oxygen content remained stable during the entire procedure in both groups (p = 0.27). Oxygen delivery index (DO₂I) increased significantly during the procedure (p < 0.01); nevertheless, the difference in DO₂I between the CPAP and NO CPAP group was nonsignificant (p = 0.61). Intrapulmonary shunt (Q_s/Q_t) increased during OLV (p < 0.01 for the time effect) and remained high until total lung ventilation was reintroduced. No difference in Q_s/Q_t was observed between the CPAP and NO CPAP groups (p = 0.98). Similarly, mean pulmonary artery pressure increased significantly during OLV and remained high at the end of the procedure in both groups (time effect p < 0.01).

CONCLUSIONS

During OLV for atrial fibrillation surgical ablation in the supine position, CPAP on the deflated lung seemed to be ineffective to reduce Q_s/Q_t or to increase arterial partial pressure of oxygen and DO₂I, provided cardiac output was maintained above 1.5 L/min/m².

Risk factors and outcomes of sepsis-associated delirium in intensive care unit patients: A secondary data analysis

OBJECTIVE

To identify the risk factors of sepsis-associated delirium and determine their effect on intensive care unit adult patient outcomes.

DESIGN

A secondary analysis of data from system development studies.

SETTING

Korean intensive care unit patients in a university hospital who were diagnosed with sepsis.

METHODS

The risk factors for sepsis-associated delirium were classified into patient factors and sepsis clinical features and were analysed using hierarchical logistic regression analysis. Outcomes included in-hospital mortality, 30-day in-hospital mortality, duration of mechanical ventilation, length of stay in the intensive care unit, length of hospital stay, total medical expenses, discharge placement, re-hospitalisation and visits to the emergency department after discharge.

RESULTS

The risk factor for sepsis-associated delirium including patients aged 65 ≥years, dependent activity and high nursing needs (patient factors), low level of consciousness, tachypnoea, and thrombocytopaenia (clinical features of sepsis). Use of vasopressors/inotropes and albumin decreased the risk of sepsis-associated delirium. Mechanical ventilation duration was prolonged and discharge to skilled nursing facilities was increased by sepsis-associated delirium.

CONCLUSIONS

The risk factors for sepsis-associated delirium increased as the severity of condition for patients with sepsis increased. Early identification of risk factors associated with sepsis-associated delirium may improve patient outcomes.

Comparative effects of fentanyl versus sufentanil on cerebral oxygen saturation and postoperative cognitive function in elderly patients undergoing open surgery

This study was aimed to systematically evaluate the effects of fentanyl and sufentanil on intraoperative cerebral oxygen saturation changes and postoperative cognitive function in elderly patients undergoing open surgery. Ninety-six elderly patients who had undergone open surgery under general anesthesia were randomly divided into fentanyl group (F group, anesthesia by fentanyl, 4 g/kg) and sufentanil group (S group, anesthesia by sufentanil, 0.4 µg/kg). There were no significant differences between the F group and S group in the general characteristics of patients. Compared to the F group, the S group had a better effect on suppressing the stress response, maintaining a stable hemodynamic status and achieving better anesthesia effects. The anesthesia recovery time of the S group was significantly shorter than that of the F group. There was no significant difference between the two groups in the intraoperative and postoperative agitation. Patient's waking time and extubation time were significantly shorter in the S group than the F group. The VAS scores in the S group were significantly lower than those in the F group at each time point. The Ramsay scores in the S group were significantly higher than those in the F group at each time point. The cerebral oxygen saturation (SctO₂) levels in both groups were significantly increased following anesthesia induction and intubation compared to that of the awake state (P < 0.05), and SctO₂ was significantly decreased during the surgery in both groups. The changes in SctO₂ levels were not significantly different between the two groups (P > 0.05). The SctO₂ level was significantly higher during surgery than that after intubation. Compared with the F group, the relative value of SctO₂ decline in the S group was smaller. Compared to the day before surgery, the Montreal Cognitive Assessment (MoCA) scores of both groups were significantly reduced after surgery. At 1 day post-surgery, the MoCA scores of the S group were significantly higher and the incidence of postoperative cognitive dysfunction (POCD) was significantly lower compared to the F group. POCD occurred in three patients (6.2%) in the S group, and the ratio was significantly lower than that in the F group (11.9%) (P < 0.05). It showed a consistent trend with the SctO₂ status during the surgery. The relative value of SctO₂ decline in the S group was significantly smaller than that in the F group. The reduction of cognitive function in the S group was significantly lower than that in the F group. These results indicate that the changes in SctO₂ are a good prediction of the incidence of POCD.

Electroencephalography and Brain Oxygenation Monitoring in the Perioperative Period

Maintaining brain function and integrity is a pivotal part of anesthesiological practice. The present overview aims to describe the current role of the 2 most frequently used monitoring methods for evaluation brain function in the perioperative period, ie, electroencephalography (EEG) and brain oxygenation monitoring. Available evidence suggests that EEG-derived parameters give additional information about depth of anesthesia for optimizing anesthetic titration. The effects on reduction of drug consumption or recovery time are heterogeneous, but most studies show a reduction of recovery times if anesthesia is titrated along processed EEG. It has been hypothesized that future EEG-derived indices will allow a better understanding of the neurophysiological principles of anesthetic-induced alteration of consciousness instead of the probabilistic approach most often used nowadays.Brain oxygenation can be either measured directly in brain parenchyma via a surgical burr hole, estimated from the venous outflow of the brain via a catheter in the jugular bulb, or assessed noninvasively by near-infrared spectroscopy. The latter method has increasingly been accepted clinically due to its ease of use and increasing evidence that near-infrared spectroscopy-derived cerebral oxygen saturation levels are associated with neurological and/or general perioperative complications and increased mortality. Furthermore, a goal-directed strategy aiming to avoid cerebral desaturations might help to reduce these complications. Recent evidence points out that this technology may additionally be used to assess autoregulation of cerebral blood flow and thereby help to titrate arterial blood pressure to the individual needs and for bedside diagnosis of disturbed autoregulation.

Comparison of the Effects of Desflurane and Sevoflurane on Cerebral Oxygen Saturation in Patients Undergoing Thyroidectomy: A Randomised Controlled Clinical Study

Objective

The commonly performed sitting position with head extended during thyroidectomy has been shown to cause adverse effects on cerebral regional oxygen saturation (CrSO2). Therefore, the present study aimed to investigate the effects of two well-known anaesthetic agents, desflurane and sevoflurane, on CrSO2 in patients undergoing thyroidectomy in the semi-sitting position by near-infra-red spectroscopy monitoring.

Methods

The study included 60 patients aged 18-65 years, with an American Society of Anesthesiologists (ASA) physical status classification score I-III, who underwent elective thyroidectomy in the semi-sitting position. The patients were randomly divided into two groups, depending on the anaesthetic agent administered: (1) sevoflurane group (Group S; n=30) and (2) desflurane group (Group D; n=30). After intubation, the patients were placed in a 45-degree semi-sitting position. Vital signs and the CrSO2 levels in both hemispheres were recorded both pre-induction and at the induction minute 1, post-intubation, post-positioning, every 5 minutes intraoperatively and in the case of sudden changes.

Results

No significant difference was found between the groups in terms of age, height, body weight, the ASA score, operative time and left- and right-hemisphere CrSO2 (p>0.05). Moreover, the two groups were statistically similar to each other with regard to peripheral capillary oxygen saturation, heart rate, systolic and diastolic blood pressure, mean artery pressure and end-tidal CO₂ (ETCO₂) levels.

Conclusion

Desflurane and sevoflurane had similar effects in the preservation of CrSO2 in patients undergoing thyroidectomy in the semi-sitting position.

Is cerebrovascular autoregulation associated with outcomes after major noncardiac surgery? A prospective observational pilot study

BACKGROUND

Studies have identified multiple risk factors for development of cognitive decline after surgery. Impaired cerebrovascular autoregulation may be a contributor to postoperative cognitive decline.

METHODS

One hundred and forty patients admitted for major elective noncardiac surgery were recruited. Near-infrared spectroscopy was used to calculate the tissue oxygenation index of dynamic autoregulation (TOx). The primary endpoint was Day 3 cognitive recovery as assessed using the Postoperative Quality of Recovery Scale. The secondary endpoint was a combined major adverse event of death, acute myocardial infarction, cardiac arrest, stroke, pulmonary embolism, sepsis, and acute kidney injury at Day 30.

RESULTS

Higher optimal TOx values, signifying impaired autoregulation, were associated with worse outcomes. Patients who cognitively recovered at Day 3 (n = 47) had lower optimal TOx values (TOx_opt ) than patients who did not recover (n = 22): 0.06 (0.24) vs 0.18 (0.16) (mean [SD]), P = 0.02. Patients who did not suffer a major adverse event (n = 102) had lower TOx_opt than patients who did (n = 17): 0.09 (0.21) vs 0.20 (0.27), P = 0.04. When dichotomized as having impaired or intact autoregulation based on TOx_opt levels, a value of TOx_opt ≥0.1 correctly identified 72.7% of patients who did not cognitively recover, OR 3.3 (1.1-9.9) (Odds ratio, [95% CI]), P = 0.03. TOx_opt ≥0.1 correctly identified 82.4% of patients who suffered a major adverse event, OR 4.7 (1.3-17.2), P = 0.02.

CONCLUSIONS

In older and higher risk patients having major noncardiac surgery, impaired cerebrovascular autoregulation was associated with failure of cognitive recovery in the early postoperative period and with 1-month mortality and morbidity.

Neurocognitive Function after Cardiac Surgery: From Phenotypes to Mechanisms

For half a century, it has been known that some patients experience neurocognitive dysfunction after cardiac surgery; however, defining its incidence, course, and causes remains challenging and controversial. Various terms have been used to describe neurocognitive dysfunction at different times after cardiac surgery, ranging from "postoperative delirium" to "postoperative cognitive dysfunction or decline." Delirium is a clinical diagnosis included in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Postoperative cognitive dysfunction is not included in the DSM-5 and has been heterogeneously defined, though a recent international nomenclature effort has proposed standardized definitions for it. Here, the authors discuss pathophysiologic mechanisms that may underlie these complications, review the literature on methods to prevent them, and discuss novel approaches to understand their etiology that may lead to novel treatment strategies. Future studies should measure both delirium and postoperative cognitive dysfunction to help clarify the relationship between these important postoperative complications.

Prospective pilot study of cerebral near infrared spectroscopy monitoring during pre-hospital anaesthesia

BACKROUND

Near-infrared spectroscopy (NIRS) provides a non-invasive measure of cerebral tissue oxygenation. The literature on application of this method in pre-hospital setting is limited. The aims of this study were to determine the feasibility of cerebral NIRS during pre-hospital anaesthesia and to quantify the changes in front lobe regional oxygen saturation (rSO2) during the pre-hospital phase.

METHODS

NIRS monitoring (Nonin SenSmart X-100) of front lobe regional oxygen saturation (rSO2) was initiated before induction of anaesthesia in 31 adult patients and continued until hospital arrival. The median age of the patients was 55 years (IQR [range] 43-63 [20-84]), and 20 (65%) of the patients were male. The indications for pre-hospital anaesthesia were neurological reasons (29%), intoxication (23%), traumatic brain injury (23%) and successful resuscitation from cardiac arrest (16%).

RESULTS

The NIRS monitoring was successful in 29 of 31 cases (94%; 95% CI: 78-99). One patient could not be monitored due to poor probe-skin contact, and 1 patient had poor contact with 1 hemisphere. Monitoring was performed for a total of 1335 minutes and was successful in both hemispheres 95% (95% CI: 94-96) of the time. The median lowest rSO2 was 8% (IQR [range] 2-13 [0-30]) below baseline, and median peak rSO2 was 7% (IQR [range] 2-11 [0-34]) above the baseline. Changes in rSO2 without accompanying changes in vital signs were observed.

CONCLUSION

NIRS is feasible during pre-hospital anaesthesia and substantial changes were observed in some patients. It provides data beyond the standard monitoring used in the pre-hospital setting.