Association between Intraoperative Hypotension and Myocardial Injury after Vascular Surgery

Prediction of myocardial ischemia-reperfusion injury post-PCI: role of sST2 levels in STEMI patients

BACKGROUND

Myocardial ischemia-reperfusion injury (MIRI) after ST-segment elevation myocardial infarction (STEMI) significantly impacts clinical outcomes. However, only a few studies have examined its clinical predictors and prognostic biomarkers.

METHODS

Patients with STEMI who received percutaneous coronary intervention (PCI) at Liaoning Provincial People's Hospital between 2020 and 2021 were enrolled in the study. Based on a thorough evaluation of clinical features, which included data obtained from intraoperative angiography and inpatient monitoring, patients were divided into the MIRI group and the non-MIRI group. Upon admission, serum solube growth stimulation expressed gene 2 protein (sST2) levels were assessed, and follow-up examinations were conducted for the patients.

RESULTS

Patients with MIRI who were admitted to the hospital present elevated serum sST2 levels (P < 0.001). Serum sST2 was recognized as a standalone risk factor contributing to the occurrence of MIRI in STEMI patients who are undergoing PCI (P < 0.001). Throughout the follow-up duration, 37 (17.0%) patients encountered major adverse cardiovascular and cerebrovascular incidents (MACCEs), which included eight (3.6%) deaths from all causes. The Kaplan-Meier assessment revealed that individuals in the MIRI group had an unfavorable prognosis (all log-rank P < 0.05). Both univariable and multivariable Cox regression models were established using MIRI patients as the study cohort. The findings indicated that sST2 levels exceeding 68.98 ng/mL served as one of independent risk factors for predicting MACCEs (all P < 0.001). The model was evaluated using the C-index, AUC, calibration plot, and Decision Curve Analysis (DCA) curve.

CONCLUSION

Elevated levels of serum sST2 may accurately predict the onset of MIRI following PCI in STEMI patients. Specifically, a serum sST2 concentration > 68.98 ng/mL is a prominent independent risk predictor for overall mortality and MACCE in individuals experiencing MIRI.

Hypotension after induction of anesthesia with remimazolam or etomidate: a non-inferiority randomized controlled trial in patients undergoing coronary artery bypass grafting

BACKGROUND

Remimazolam is a novel ultra-short-acting benzodiazepine known for its hemodynamic stability over propofol. However, its hemodynamic effects compared to those of etomidate are not well established. This study aimed to determine whether the use of remimazolam is non-inferior to etomidate with regard to the occurrence of post-induction hypotension in patients undergoing coronary artery bypass grafting.

METHODS

Patients were randomly assigned to either the remimazolam group (6 mg/kg/h) or the etomidate group (0.3 mg/kg) for induction of anesthesia. Anesthetic depth was adjusted based on the bispectral index. Primary outcome was the incidence of post-induction hypotension, defined as a mean arterial pressure less than 65 mmHg within 15 min after endotracheal intubation, with a non-inferiority margin of 12%.

RESULTS

A total of 144 patients were finally analyzed. Incidence of post-induction hypotension was 36/71 (50.7%) in the remimazolam group and 25/73 (34.2%) in the etomidate group, with a rate difference of 16.5% (95% CI [3.0-32.6]) between the two groups that was beyond the prespecified non-inferiority margin of 12.0%. The number of patients who needed vasopressors was similar in the two groups.

CONCLUSIONS

In this non-inferiority trial, remimazolam failed to show non-inferiority to etomidate in terms of post-induction hypotension when used as an induction drug for general anesthesia in patients undergoing coronary artery bypass grafting. However, different doses or infusion techniques of remimazolam should be compared with etomidate in various patient groups to fully assess its hemodynamic non-inferiority during induction of anesthesia.

Navigating Cardiovascular Events in Non-Cardiac Surgery: A Comprehensive Review of Complications and Risk Assessment Strategies

Cardiovascular complications following non-cardiac surgery pose a significant global concern, affecting millions of patients annually. These complications, ranging from asymptomatic troponin elevations to major adverse cardiac events, contribute to heightened morbidity, mortality, and health care expenditures. The underlying mechanisms involve oxygen supply-demand imbalances and acute coronary syndromes precipitated by perioperative stressors. High-risk surgeries, including vascular and major abdominal procedures, are particularly susceptible to these complications. Risk assessment tools and biomarkers, especially high-sensitivity cardiac troponins, play pivotal roles in prognostication. However, despite advances in perioperative care, optimal management strategies remain elusive, as underscored by conflicting guidelines regarding interventions such as β-blockers and statins. This review aims to consolidate current evidence on cardiovascular complications following non-cardiac surgery, evaluate the utility of biomarkers, and discuss international guidelines for risk mitigation. An enhanced understanding regarding the standardized approaches is imperative in mitigating these complications effectively. Further research is essential to refine risk prediction models, validate biomarker thresholds, and elucidate the efficacy of preventive measures. Addressing these challenges can eventually lead to improved patient outcomes and more efficient healthcare resource utilization worldwide.

Diastolic Versus Systolic or Mean Intraoperative Hypotension as Predictive of Perioperative Myocardial Injury in a White-Box Machine-Learning Model

BACKGROUND

Intraoperative hypotension (IOH) and tachycardia are associated with perioperative myocardial injury (PMI), and thereby increased postoperative mortality. Patients undergoing vascular surgery are specifically at risk of developing cardiac complications. This study aimed to explore the association between different thresholds for IOH and tachycardia, and PMI. It also aimed to explore which threshold for IOH and tachycardia best predicts PMI.

METHODS

In this single-center prospective observational study, high-sensitivity cardiac troponin T was measured preoperatively and at 4, 24, and 48 hours after vascular surgery. Absolute and relative thresholds were used to define intraoperative systolic, mean, and diastolic arterial hypotension, measured every 15 seconds by invasive arterial pressure monitoring and heart rate using the Philips IntelliVue X3 monitor. Decision tree machine-learning (ML) models were used to explore which thresholds for IOH and tachycardia best predict PMI. Clinical utility and transparency were prioritized over maximizing the performance of the ML model and therefore a white-box model was used.

RESULTS

In all, 498 patients were included in the study. Ninety-nine patients (20%) had PMI. Significant associations were found between IOH and PMI using both absolute and relative thresholds for systolic, mean, and diastolic arterial pressure. Absolute thresholds based on diastolic arterial pressure had the strongest correlation with PMI and yielded greater statistical significance. The threshold that was most predictive of PMI was an absolute diastolic arterial pressure <44 mm Hg. The prediction model with the absolute threshold of diastolic arterial pressure <44 mm Hg had a macro average F1 score of 0.67 and a weighted average F1 score of 0.76. No association was found between tachycardia and PMI.

CONCLUSIONS

We found that an absolute, not relative, IOH threshold based on diastolic arterial pressure, and not systolic or mean arterial pressure, or tachycardia, was most predictive of PMI.

The hypotension prediction index in major abdominal surgery - A prospective randomised clinical trial protocol

Background

Patients undergoing major abdominal surgery are at increased risk of developing perioperative hypotension, which is associated with increased mortality and morbidity. Despite using advanced technologies such as evaluating arterial pressure derived cardiac output, anaesthetic management to maintain hemodynamic stability is still reactive when the clinical decision is made after hypotension has developed. Previous perioperative goal-directed studies have not proven the benefits of this approach with high certainty. A new, approved technology called the Hypotension Prediction Index (HPI) aims to prevent hypotension occurrence by allowing the precise hemodynamic monitoring of patients under general anaesthesia, significantly reducing intraoperative hypotension events. This prospective randomised clinical trial aims to compare the rate of perioperative hypotension in patients undergoing major abdominal surgery according to their type of hemodynamic monitoring.

Methods

and Analysis: Patients meeting the inclusion criteria will be randomly assigned to receive hemodynamic assessment with arterial pressure cardiac output (APCO) monitoring (group A) or hemodynamic monitoring with the HPI software (group B). The primary outcome is a time-weighted average (TWA) mean arterial pressure (MAP) of <65 mmHg: TWA MAP = (depth of hypotension [in mmHg] below a MAP of 65 mmHg × time [in minutes] spent below a MAP of 65 mmHg)/total duration of the operation (in minutes). Its secondary outcomes include perioperative hemodynamic management and the rate of postoperative complications.

Ethics and dissemination

This trial was approved by the Ethics Committee of the Poznan University of Medical Sciences (KB-559/220; date: 01/07/2022). Its results will be submitted for publication in a peer-reviewed journal.

Trial registration number

NCT06247384.

Continuation versus discontinuation of renin-angiotensin aldosterone system inhibitors before non-cardiac surgery: A systematic review and meta-analysis

BACKGROUND

A large number of patients undergoing noncardiac surgeries are on long-term use of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARBs). The current guidelines regarding the continuation or discontinuation of renin-angiotensin-aldosterone system inhibitors (RAAS) inhibitors before noncardiac surgery are conflicting. This meta-analysis aims to evaluate whether continuing or withholding RAAS inhibitors before noncardiac surgery influences perioperative mortality and complications.

METHODS

A thorough literature search was performed across PubMed/MEDLINE, Embase, and the Cochrane Library from their inception up to August 30, 2024 to identify eligible randomized controlled trials (RCTs) and cohort studies. Clinical outcomes were evaluated using a random-effects model to pool odds ratios (ORs) with 95 % confidence intervals (CIs).

RESULTS

The analysis included 16 studies with a total of 59,105 patients on RAAS inhibitors before noncardiac surgery. Withholding RAAS inhibitors was associated with a significantly lower incidence of intraoperative hypotension (OR = 0.49; 95 % CI = 0.29 to 0.83) and acute kidney injury (AKI) (OR = 0.88; 95 % CI = 0.82 to 0.95) than continuing the therapy. However, there was no statistically significant difference in reducing mortality (OR = 1.10; 95 % CI = 0.86 to 1.40), major adverse cardiovascular events (MACE) (OR = 1.27; 95 % CI = 0.75 to 2.16), myocardial infarction (OR = 0.83; 95 % CI = 0.27 to 2.59) or stroke events (OR = 0.70; 95 % CI = 0.36 to 1.36) between the two groups.

CONCLUSION

Withholding RAAS inhibitors before noncardiac surgery reduces intraoperative hypotension and AKI with nonsignificant effects on mortality and MACE.

Effect of prophylactic infusion of norepinephrine on the prevention of hypotension during vertebroplasty: a randomized clinical trial

BACKGROUND

Transient hypotension is a common occurrence during the implantation of bone cement. This placebo-controlled randomized clinical trial study investigated the effect of prophylactic infusion of norepinephrine on the incidence of hypotension in senior patients who underwent vertebroplasty.

METHODS

The trial recruited patients who were greater than or equal to 65 years of age, had an American Society of Anesthesiologist physical status classification of I to III, and underwent vertebroplasty from August 2020 to August 2021 at the Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine in China. The patients were randomly grouped according to whether they received either a norepinephrine infusion of 0.05 µg/kg/min or an equivalent volume of saline 10 min before implantation of bone cement. Intraoperative hemodynamics were monitored continuously by the MostCare system at the following 7 time points: 10 min before implantation of bone cement and immediately, 30 s, 1, 3, 5, and 10 min after implantation of bone cement. We also recorded the number of hypotensive episodes and the total number of vasopressors after implantation of bone cement. Multivariable logistic regression was used to assess the risk factors associated with hypotension after implantation of bone cement.

RESULTS

A total of 63 patients were randomized to the control group (n = 31; median [IQR] age, 74 [69-79] years) and the norepinephrine group (n = 32; median [IQR] age, 75 [71-79] years). The incidence of hypotension in the norepinephrine group was significantly lower than that in the control group after implantation of bone cement (12.5% vs. 45.2%; relative risk [RR], 3.61 [95% CI, 1.13-15.07]; P = 0.005). Moreover, the median (IQR) number of hypotensive episodes (0 [0-0] vs. 0 [0-2]; P = 0.005) and the total number of vasopressors (0 [0-0] vs. 0 [0-1]; P = 0.004) in the norepinephrine group were significantly lower than those in the control group. Furthermore, compared with the baseline, the MAP significantly decreased at 1 min (P = 0.007) and 3 min (P < 0.001) after bone cement implantation in the control group. However, the MAP at 3 min in the norepinephrine group was significantly higher than that in the control group (P < 0.001). The incidence of complications was not different between the groups. In multivariable logistic regression, the FRAIL score (OR, 2.29; 95% CI, 1.21-4.31) was identified as a risk factor associated with hypotension.

CONCLUSION

Prophylactic infusion of norepinephrine before bone cement implantation can stabilize hemodynamics and reduce the incidence of hypotension after implantation of bone cement.

Intraoperative hypotension is associated with decreased long-term survival in older patients after major noncardiac surgery: Secondary analysis of three randomized trials

STUDY OBJECTIVE

To assess the association of intraoperative hypotension with long-term survivals in older patients after major noncardiac surgery mainly for cancer.

DESIGN

A secondary analysis of databases from three randomized trials with long-term follow-up.

SETTING

The underlying trials were conducted in 17 tertiary hospitals in China.

PATIENTS

Patients aged 60 to 90 years who underwent major noncardiac thoracic or abdominal surgeries (≥ 2 h) in a single center were included in this analysis.

EXPOSURES

Restricted cubic spline models were employed to determine the lowest mean arterial pressure (MAP) threshold that was potentially harmful for long-term survivals. Patients were arbitrarily divided into three groups according to the cumulative duration or area under the MAP threshold. The association between intraoperative hypotension exposure and long-term survivals were analyzed with the Cox proportional hazard regression models.

MEASUREMENTS

Our primary endpoint was overall survival. Secondary endpoints included recurrence-free and event-free survivals.

MAIN RESULTS

A total of 2664 patients (mean age 69.0 years, 34.9% female sex, 92.5% cancer surgery) were included in the final analysis. MAP < 60 mmHg was adopted as the threshold of intraoperative hypotension. Patients were divided into three groups according to duration under MAP < 60 mmHg (<1 min, 1-10 min, and > 10 min) or area under MAP <60 mmHg (< 1 mmHg⋅min, 1-30 mmHg⋅min, and > 30 mmHg⋅min). After adjusting confounders, duration under MAP < 60 mmHg for > 10 min was associated with a shortened overall survival when compared with the < 1 min patients (adjusted hazard ratio [HR] 1.31, 95% confidence interval [CI] 1.09 to 1.57, P = 0.004); area under MAP < 60 mmHg for > 30 mmHg⋅min was associated with a shortened overall survival when compared with the < 1 mmHg⋅min patients (adjusted HR 1.40, 95% CI 1.16 to 1.68, P < 0.001). Similar associations exist between duration under MAP < 60 mmHg for > 10 min or area under MAP < 60 mmHg for > 30 mmHg⋅min and recurrence-free or event-free survivals.

CONCLUSIONS

In older patients who underwent major noncardiac surgery mainly for cancer, intraoperative hypotension was associated with worse overall, recurrence-free, and event-free survivals.

Frequency Domain Deep Learning With Non-Invasive Features for Intraoperative Hypotension Prediction

BACKGROUND

Intraoperative hypotension can lead to postoperative organ dysfunction. Previous studies primarily used invasive arterial pressure as the key biosignal for the detection of hypotension. However, these studies had limitations in incorporating different biosignal modalities and utilizing the periodic nature of biosignals. To address these limitations, we utilized frequency-domain information, which provides key insights that time-domain analysis cannot provide, as revealed by recent advances in deep learning. With the frequency-domain information, we propose a deep-learning approach that integrates multiple biosignal modalities.

METHODS

We used the discrete Fourier transform technique, to extract frequency information from biosignal data, which we then combined with the original time-domain data as input for our deep learning model. To improve the interpretability of our results, we incorporated recent interpretable modules for deep-learning models into our analysis.

RESULTS

We constructed 75 994 segments from the data of 3226 patients to predict hypotension during surgery. Our proposed frequency-domain deep-learning model outperformed conventional approaches that rely solely on time-domain information. Notably, our model achieved a greater increase in AUROC performance than the time-domain deep learning models when trained on non-invasive biosignal data only (AUROC 0.898 [95% CI: 0.885-0.91] vs. 0.853 [95% CI: 0.839-0.867]). Further analysis revealed that the 1.5-3.0 Hz frequency band played an important role in predicting hypotension events.

CONCLUSION

Utilizing the frequency domain not only demonstrated high performance on invasive data but also showed significant performance improvement when applied to non-invasive data alone. Our proposed framework offers clinicians a novel perspective for predicting intraoperative hypotension.

Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery: Guidelines of the German Society of Anaesthesiology and Intensive Care Medicine in collaboration with the German Association of the Scientific Medical Societies

Haemodynamic monitoring and management are cornerstones of perioperative care. The goal of haemodynamic management is to maintain organ function by ensuring adequate perfusion pressure, blood flow, and oxygen delivery. We here present guidelines on "Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery" that were prepared by 18 experts on behalf of the German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und lntensivmedizin; DGAI).

Predictive ability of hypotension prediction index and machine learning methods in intraoperative hypotension: a systematic review and meta-analysis

INTRODUCTION

Intraoperative Hypotension (IOH) poses a substantial risk during surgical procedures. The integration of Artificial Intelligence (AI) in predicting IOH holds promise for enhancing detection capabilities, providing an opportunity to improve patient outcomes. This systematic review and meta analysis explores the intersection of AI and IOH prediction, addressing the crucial need for effective monitoring in surgical settings.

METHOD

A search of Pubmed, Scopus, Web of Science, and Embase was conducted. Screening involved two-phase assessments by independent reviewers, ensuring adherence to predefined PICOS criteria. Included studies focused on AI models predicting IOH in any type of surgery. Due to the high number of studies evaluating the hypotension prediction index (HPI), we conducted two sets of meta-analyses: one involving the HPI studies and one including non-HPI studies. In the HPI studies the following outcomes were analyzed: cumulative duration of IOH per patient, time weighted average of mean arterial pressure < 65 (TWA-MAP < 65), area under the threshold of mean arterial pressure (AUT-MAP), and area under the receiver operating characteristics curve (AUROC). In the non-HPI studies, we examined the pooled AUROC of all AI models other than HPI.

RESULTS

43 studies were included in this review. Studies showed significant reduction in IOH duration, TWA-MAP < 65 mmHg, and AUT-MAP < 65 mmHg in groups where HPI was used. AUROC for HPI algorithms demonstrated strong predictive performance (AUROC = 0.89, 95CI). Non-HPI models had a pooled AUROC of 0.79 (95CI: 0.74, 0.83).

CONCLUSION

HPI demonstrated excellent ability to predict hypotensive episodes and hence reduce the duration of hypotension. Other AI models, particularly those based on deep learning methods, also indicated a great ability to predict IOH, while their capacity to reduce IOH-related indices such as duration remains unclear.

Development and validation of a predictive model for PACU hypotension in elderly patients undergoing sedated gastrointestinal endoscopy

BACKGROUND

Hypotension, characterized by abnormally low blood pressure, is a frequently observed adverse event in sedated gastrointestinal endoscopy procedures. Although the examination time is typically short, hypotension during and after gastroscopy procedures is frequently overlooked or remains undetected. This study aimed to construct a risk nomogram for post-anesthesia care unit (PACU) hypotension in elderly patients undergoing sedated gastrointestinal endoscopy.

METHODS

This study involved 2919 elderly patients who underwent sedated gastrointestinal endoscopy. A preoperative questionnaire was used to collect data on patient characteristics; intraoperative medication use and adverse events were also recorded. The primary objective of the study was to evaluate the risk of PACU hypotension in these patients. To achieve this, the least absolute shrinkage and selection operator (LASSO) regression analysis method was used to optimize variable selection, involving cyclic coordinate descent with tenfold cross-validation. Subsequently, multivariable logistic regression analysis was applied to build a predictive model using the selected predictors from the LASSO regression. A nomogram was visually developed based on these variables. To validate the model, a calibration plot, receiver operating characteristic (ROC) curve, and decision curve analysis (DCA) were used. Additionally, external validation was conducted to further assess the model's performance.

RESULTS

The LASSO regression analysis identified predictors associated with an increased risk of adverse events during surgery: age, duration of preoperative water abstinence, intraoperative mean arterial pressure (MAP) <65 mmHg, decreased systolic blood pressure (SBP), and use of norepinephrine (NE). The constructed model based on these predictors demonstrated moderate predictive ability, with an area under the ROC curve of 0.710 in the training set and 0.778 in the validation set. The DCA indicated that the nomogram had clinical applicability when the risk threshold ranged between 20 and 82%, which was subsequently confirmed in the external validation with a range of 18-92%.

CONCLUSION

Incorporating factors such as age, duration of preoperative water abstinence, intraoperative MAP <65 mmHg, decreased SBP, and use of NE in the risk nomogram increased its usefulness for predicting PACU hypotension risk in elderly patient undergoing sedated gastrointestinal endoscopy.

Effect of pericapsular nerve group block and suprainguinal fascia iliaca block on postoperative analgesia and stress response in elderly patients undergoing hip arthroplasty: a prospective randomized controlled double-blind trial

BACKGROUND

As a novel regional analgesic technique, ultrasound-guided pericapsular nerve group (PENG) block has some potential advantages, and we designed a randomized clinical trial (RCT) to investigate whether the ultrasound-guided PENG block combined with general anesthesia can better reduce stress response, maintain intraoperative hemodynamic stability, and reduce postoperative analgesia in elderly hip arthroplasty compared with ultrasound-guided suprainguinal fascia iliaca block (SIFIB) combined with general anesthesia.

METHODS

Seventy-four subjects were enrolled over an 8-month period (20 April 2023 to 31 December 2023). All patients were divided into the test group (group P) and the control group (group S) using the envelope as the randomization method. The test group was treated with preoperative ultrasound-guided PENG block analgesia combined with general anesthesia and the control group was treated with preoperative ultrasound-guided SIFIB analgesia combined with general anesthesia. The primary outcome selected was the patient Visual Analogue Scale (VAS) score at 12 h postoperatively.

RESULTS

After generalized estimating equations (GEE) analysis, there was a statistically significant difference in the main effect of postoperative VAS score in group P compared with group S (P = 0.009), the time effect of VAS score in each group was significantly different (P < 0.001), and there was no statistically significant difference in the group-time interaction effect (P = 0.069). There was no statistically significant difference in the main effect of intraoperative mean arterial pressure (MAP) change (P = 0.911), there were statistically significant differences in the time effect of MAP in each group (P < 0.001), and there were statistically significant differences in the interaction effect (P < 0.001).

CONCLUSIONS

In summary, we can conclude that in elderly patients undergoing hip fracture surgery, postoperative analgesia is more pronounced, intraoperative hemodynamic parameters are more stable, and intraoperative stress is less induced in patients receiving SIFIB than in patients receiving PENG block.

The exploration of perioperative hypotension subtypes: a prospective, single cohort, observational pilot study

Background

Hypotension is a risk factor for postoperative complications, but evidence from randomized trials does not support that a higher blood pressure target always leads to optimized outcomes. The heterogeneity of underlying hemodynamics during hypotension may contribute to these contradictory results. Exploring the subtypes of hypotension can enable optimal management of intraoperative hypotension.

Methods

This is a prospective, observational pilot study. Patients who were ≥ 45 years old and scheduled to undergo moderate-to-high-risk noncardiac surgery were enrolled in this study. The primary objective of this pilot study was to investigate the frequency and distribution of perioperative hypotension and its subtypes (hypotension with or without cardiac output reduction). The exposure of hypotension and its subtypes in patients with and without myocardial or acute kidney injury were also explored.

Results

Sixty patients were included in the analysis. 83% (50/60) of the patients experienced perioperative hypotension. The median duration of hypotension for each patient was 8.0 [interquartile range, 3.1-23.3] minutes. Reduced cardiac output was present during 77% of the hypotension duration. Patients suffering from postoperative myocardial or acute kidney injury displayed longer duration and more extensive exposure in all hypotension subtypes. However, the percentage of different hypotension subtypes did not differ in patients with or without postoperative myocardial or acute kidney injury.

Conclusion

Perioperative hypotension was frequently accompanied by cardiac output reduction in moderate-to-high-risk noncardiac surgical patients. However, due to the pilot nature of this study, the relationship between hypotension subtypes and postoperative myocardial or acute kidney injury still needs further exploration.

Clinical trial registration

https://www.chictr.org.cn/showprojEN.html?proj=134260, CTR2200055929.

Computer-controlled closed-loop norepinephrine infusion system for automated control of mean arterial pressure in dogs under isoflurane-induced hypotension: a feasibility study

Introduction

Intra-operative hypotension is a common complication of surgery under general anesthesia in dogs and humans. Computer-controlled closed-loop infusion systems of norepinephrine (NE) have been developed and clinically applied for automated optimization of arterial pressure (AP) and prevention of intra-operative hypotension in humans. This study aimed to develop a simple computer-controlled closed-loop infusion system of NE for the automated control of the mean arterial pressure (MAP) in dogs with isoflurane-induced hypotension and to validate the control of MAP by the developed system.

Methods

NE was administered via the cephalic vein, whereas MAP was measured invasively by placing a catheter in the dorsal pedal artery. The proportional-integral-derivative (PID) controller in the negative feedback loop of the developed system titrated the infusion rate of NE to maintain the MAP at the target value of 60 mmHg. The titration was updated every 2 s. The performance of the developed system was evaluated in six laboratory Beagle dogs under general anesthesia with isoflurane.

Results

In the six dogs, when the concentration [median (interquartile range)] of inhaled isoflurane was increased from 1.5 (1.5-1.5)% to 4 (4-4)% without activating the system, the MAP was lowered from 95 (91-99) to 41 (37-42) mmHg. In contrast, when the concentration was increased from 1.5 (1.0-1.5)% to 4 (4-4.8)% for a 30-min period and the system was simultaneously activated, the MAP was temporarily lowered from 92 (89-95) to 47 (43-49) mmHg but recovered to 58 (57-58) mmHg owing to the system-controlled infusion of NE. If the acceptable target range for MAP was defined as target MAP ±5 mmHg (55 ≤ MAP ≤65 mmHg), the percentage of time wherein the MAP was maintained within the acceptable range was 96 (89-100)% in the six dogs during the second half of the 30-min period (from 15 to 30 min after system activation). The median performance error, median absolute performance error, wobble, and divergence were - 2.9 (-4.7 to 1.9)%, 2.9 (2.0-4.7)%, 1.3 (0.8-1.8)%, and - 0.24 (-0.34 to -0.11)%·min-1, respectively. No adverse events were observed during the study period, and all dogs were extubated uneventfully.

Conclusion

This system was able to titrate the NE infusion rates in an accurate and stable manner to maintain the MAP within the predetermined target range in dogs with isoflurane-induced hypotension. This system can be a potential tool in daily clinical practice for the care of companion dogs.

Goal-directed therapy guided by the FloTrac sensor in major surgery: a systematic review and meta-analysis

OBJECTIVE

To provide insights into the potential benefits of goal-directed therapy guided by FloTrac in reducing postoperative complications and improving outcomes.

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials to evaluate goal-directed therapy guided by FloTrac in major surgery, comparing goal-directed therapy with usual care or invasive monitoring in cardiac and noncardiac surgery subgroups. The quality of the articles and evidence were evaluated with a risk of bias tool and GRADE.

RESULTS

We included 29 randomized controlled trials with 3,468 patients. Goal-directed therapy significantly reduced the duration of hospital stay (mean difference -1.43 days; 95%CI 2.07 to -0.79; I2 81%), intensive care unit stay (mean difference -0.77 days; 95%CI -1.18 to -0.36; I2 93%), and mechanical ventilation (mean difference -2.48 hours, 95%CI -4.10 to -0.86, I2 63%). There was no statistically significant difference in mortality, myocardial infarction, acute kidney injury or hypotension, but goal-directed therapy significantly reduced the risk of heart failure or pulmonary edema (RR 0.46; 95%CI 0.23 - 0.92; I2 0%).

CONCLUSION

Goal-directed therapy guided by the FloTrac sensor improved clinical outcomes and shortened the length of stay in the hospital and intensive care unit in patients undergoing major surgery. Further research can validate these results using specific protocols and better understand the potential benefits of FloTrac beyond these outcomes.

Intraoperative hypotension and its association with acute kidney injury in patients undergoing elective cardiac surgery: a large retrospective cohort study

BACKGROUND

Intraoperative hypotension (IOH) is known to affect renal outcomes in noncardiac surgery. However, it is unclear whether intraoperative hypotension (IOH) causes postoperative acute kidney injury following cardiac surgery.

OBJECTIVE

This study aimed to determine whether the duration of IOH during cardiac surgery is associated with the incidence of postoperative acute kidney injury (AKI) and identify its impact on long-term outcomes.

DESIGN

Retrospective cohort study.

SETTING

Academic university hospital (Heart and Diabetes Center, Bad Oeynhausen, Germany).

PATIENTS

A cohort of 28 909 patients who underwent elective cardiac surgery between 1 January 2009 and 31 December 2018.

INTERVENTIONS

IOH was defined as intraoperative mean arterial blood pressure (MAP) of less than 60 mmHg for more than 2 min. The cumulative duration of these IOH events was recorded each patient.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of AKI according to the KDIGO criteria (Kidney Disease: Improving Global Outcomes). Logistic regression analysis was used to analyse the associations between IOH and the incidence of AKI. Secondary outcomes were the independent predictors for the incidence of AKI.

RESULTS

Postoperative AKI was observed in 42.9% of patients. The cumulative duration of IOH (minutes) had a significant influence on the incidence of AKI [odds ratio (OR) 1.004; 95% confidence interval (CI) 1.003 to 1.005; P < 0.001] (P > 0.001 versus P < 0.001). The survival time was significantly shorter in patients with a higher cumulative duration of IOH, patients aged more than 70 years, and those who developed AKI (P < 0.001). Logistic regression analysis identified eight predictors of AKI: age, cumulative duration of IOH, duration of surgery, chronic obstructive pulmonary disease, body mass index, type of surgery, American Society of Anesthesiologists stage, and Euroscore 2.

CONCLUSIONS

The cumulative duration of IOH is an independent risk factor for the occurrence of postoperative AKI after cardiac surgery.

TRIAL REGISTRATION

Ethics Committee of the Ruhr University Bochum (Register number 2019-491).

Pathophysiological mechanisms underlying increased circulating cardiac troponin in noncardiac surgery: a narrative review

Assay-specific increases in circulating cardiac troponin are observed in 20-40% of patients after noncardiac surgery, depending on patient age, type of surgery, and comorbidities. Increased cardiac troponin is consistently associated with excess morbidity and mortality after noncardiac surgery. Despite these findings, the underlying mechanisms are unclear. The majority of interventional trials have been designed on the premise that ischaemic cardiac disease drives elevated perioperative cardiac troponin concentrations. We consider data showing that elevated circulating cardiac troponin after surgery could be a nonspecific marker of cardiomyocyte stress. Elevated concentrations of circulating cardiac troponin could reflect coordinated pathological processes underpinning organ injury that are not necessarily caused by ischaemia. Laboratory studies suggest that matching of coronary artery autoregulation and myocardial perfusion-contraction coupling limit the impact of systemic haemodynamic changes in the myocardium, and that type 2 ischaemia might not be the likeliest explanation for cardiac troponin elevation in noncardiac surgery. The perioperative period triggers multiple pathological mechanisms that might cause cardiac troponin to cross the sarcolemma. A two-hit model involving two or more triggers including systemic inflammation, haemodynamic strain, adrenergic stress, and autonomic dysfunction might exacerbate or initiate acute myocardial injury directly in the absence of cell death. Consideration of these diverse mechanisms is pivotal for the design and interpretation of interventional perioperative trials.

AcumenTM hypotension prediction index guidance for prevention and treatment of hypotension in noncardiac surgery: a prospective, single-arm, multicenter trial

BACKGROUND

Intraoperative hypotension is common during noncardiac surgery and is associated with postoperative myocardial infarction, acute kidney injury, stroke, and severe infection. The Hypotension Prediction Index software is an algorithm based on arterial waveform analysis that alerts clinicians of the patient's likelihood of experiencing a future hypotensive event, defined as mean arterial pressure < 65 mmHg for at least 1 min.

METHODS

Two analyses included (1) a prospective, single-arm trial, with continuous blood pressure measurements from study monitors, compared to a historical comparison cohort. (2) A post hoc analysis of a subset of trial participants versus a propensity score-weighted contemporaneous comparison group, using external data from the Multicenter Perioperative Outcomes Group (MPOG). The trial included 485 subjects in 11 sites; 406 were in the final effectiveness analysis. The post hoc analysis included 457 trial participants and 15,796 comparison patients. Patients were eligible if aged 18 years or older, American Society of Anesthesiologists (ASA) physical status 3 or 4, and scheduled for moderate- to high-risk noncardiac surgery expected to last at least 3 h.

MEASUREMENTS

minutes of mean arterial pressure (MAP) below 65 mmHg and area under MAP < 65 mmHg.

RESULTS

Analysis 1: Trial subjects (n = 406) experienced a mean of 9 ± 13 min of MAP below 65 mmHg, compared with the MPOG historical control mean of 25 ± 41 min, a 65% reduction (p < 0.001). Subjects with at least one episode of hypotension (n = 293) had a mean of 12 ± 14 min of MAP below 65 mmHg compared with the MPOG historical control mean of 28 ± 43 min, a 58% reduction (p< 0.001). Analysis 2: In the post hoc inverse probability treatment weighting model, patients in the trial demonstrated a 35% reduction in minutes of hypotension compared to a contemporaneous comparison group [exponentiated coefficient: - 0.35 (95%CI - 0.43, - 0.27); p < 0.001].

CONCLUSIONS

The use of prediction software for blood pressure management was associated with a clinically meaningful reduction in the duration of intraoperative hypotension. Further studies must investigate whether predictive algorithms to prevent hypotension can reduce adverse outcomes.

TRIAL REGISTRATION

Clinical trial number: NCT03805217. Registry URL: https://clinicaltrials.gov/ct2/show/NCT03805217 . Principal investigator: Xiaodong Bao, MD, PhD. Date of registration: January 15, 2019.

Comparative outcomes of awake spine surgery under spinal versus general anesthesia: a comprehensive systematic review and meta-analysis

BACKGROUND

Awake surgery, under spinal anesthesia (SA), is an alternative to surgery under general anesthesia (GA), in neurological and spine surgery. In the literature, there seem to be some evidence supporting benefits associated with the use of this anesthetic modality, as compared to GA. Currently, there is a notable lack of updated and comprehensive review addressing the complications associated with both awake SA and GA in spine surgery. We hence aimed to perform a systematic review of the literature and meta-analysis on the topic.

METHODS

A systematic search was conducted to identify studies that assessed SA in spine surgery from database inception to April 14, 2023, in PubMed, Medline, Embase, and Cochrane databases. Outcomes of interest included estimated blood loss, length of hospital stay, operative time, and overall complications. Meta-analysis was conducted using random effects models.

RESULTS

In total, 38 studies that assessed 7820 patients were included. The majority of the operations that were treated with SA were single-level lumbar cases. Awake patients had significantly shorter lengths of hospital stay (Mean difference (MD): - 0.40 days; 95% CI - 0.64 to - 0.17) and operative time (MD: - 19.17 min; 95% CI - 29.68 to - 8.65) compared to patients under GA. The overall complication rate was significantly higher in patients under GA than SA (RR, 0.59 [95% CI 0.47-0.74]). Patients under GA had significantly higher rates of postoperative nausea/vomiting RR, 0.60 [95% CI 0.39-0.90]) and urinary retention (RR, 0.61 [95% CI 0.37-0.99]).

CONCLUSIONS

Patients undergoing awake spine surgery under SA had significantly shorter operations and hospital stays, and fewer rates of postoperative nausea and urinary retention as compared to GA. In summary, awake spine surgery offers a valid alternative to GA and added benefits in terms of postsurgical complications, while being associated with relatively low morbidity.

Continuous vs intermittent Non-Invasive blood pressure MONitoring in preventing postoperative organ failure (niMON): study protocol for an open-label, multicenter randomized trial

BACKGROUND

Blood pressure has become one of the most important vital signs to monitor in the perioperative setting. Recently, the Italian Society of Anesthesia Analgesia Resuscitation and Intensive Care (SIAARTI) recommended, with low level of evidence, continuous monitoring of blood pressure during the intraoperative period. Continuous monitoring allows for early detection of hypotension, which may potentially lead to a timely treatment. Whether the ability to detect more hypotension events by continuous noninvasive blood pressure (C-NiBP) monitoring can improve patient outcomes is still unclear. Here, we report the rationale, study design, and statistical analysis plan of the niMON trial, which aims to evaluate the effect of intraoperative C-NiBP compared with intermittent (I-NiBP) monitoring on postoperative myocardial and renal injury.

METHODS

The niMon trial is an investigator-initiated, multicenter, international, open-label, parallel-group, randomized clinical trial. Eligible patients will be randomized in a 1:1 ratio to receive C-NiBP or I-NiBP as an intraoperative monitoring strategy. The proportion of patients who develop myocardial injury in the first postoperative week is the primary outcome; the secondary outcomes are the proportions of patients who develop postoperative AKI, in-hospital mortality rate, and 30 and 90 postoperative days events. A sample size of 1265 patients will provide a power of 80% to detect a 4% absolute reduction in the rate of the primary outcome.

CONCLUSIONS

The niMON data will provide evidence to guide the choice of the most appropriate intraoperative blood pressure monitoring strategy.

CLINICAL TRIAL REGISTRATION

Clinical Trial Registration: NCT05496322, registered on the 5th of August 2023.

The Incidence of Perioperative Hypotension in Patients Undergoing Major Abdominal Surgery with the Use of Arterial Waveform Analysis and the Hypotension Prediction Index Hemodynamic Monitoring-A Retrospective Analysis

Intraoperative hypotension (IH) is common in patients receiving general anesthesia and can lead to serious complications such as kidney failure, myocardial injury and increased mortality. The Hypotension Prediction Index (HPI) algorithm is a machine learning system that analyzes the arterial pressure waveform and alerts the clinician of an impending hypotension event. The purpose of the study was to compare the frequency of perioperative hypotension in patients undergoing major abdominal surgery with different types of hemodynamic monitoring. The study included 61 patients who were monitored with the arterial pressure-based cardiac output (APCO) technology (FloTrac group) and 62 patients with the Hypotension Prediction Index algorithm (HPI group). Our primary outcome was the time-weighted average (TWA) of hypotension below < 65 mmHg. The median TWA of hypotension in the FloTrac group was 0.31 mmHg versus 0.09 mmHg in the HPI group (p = 0.000009). In the FloTrac group, the average time of hypotension was 27.9 min vs. 8.1 min in the HPI group (p = 0.000023). By applying the HPI algorithm in addition to an arterial waveform analysis alone, we were able to significantly decrease the frequency and duration of perioperative hypotension events in patients who underwent major abdominal surgery.

Effect of carotid corrected flow time combined with perioperative fluid therapy on preventing hypotension after general anesthesia induction in elderly patients: a prospective cohort study

BACKGROUND

Hypotension often occurs following the induction of general anesthesia in elderly patients undergoing surgery and can lead to severe complications. This study assessed the effect of carotid corrected flow time (FTc) combined with perioperative fluid therapy on preventing hypotension after general anesthesia induction in elderly patients.

MATERIALS AND METHODS

The prospective cohort study was divided into two parts. The first part (Part I) consisted of 112 elderly patients. Carotid FTc was measured using Color Doppler Ultrasound 5 min before anesthesia induction. Hypotension was defined as a decrease of greater than 30% in systolic blood pressure (SBP) or a decrease of greater than 20% in mean arterial pressure (MAP) from baseline, or an absolute SBP below 90 mmHg and MAP below 60 mmHg within 3 min after induction of general anesthesia. The predictive value of carotid FTc was determined using receiver operating characteristic (ROC) curve. The second part (Part II) consisted of 65 elderly patients. Based on the results in Part I, elderly patients with carotid FTc below the optimal cut-off value received perioperative fluid therapy at a volume of 8 ml/kg of balanced crystalloids (lactated Ringer's solution) in 30 min before induction. The effect of carotid FTc combined with perioperative fluid therapy was assessed by comparing observed incidence of hypotension after induction.

RESULTS

The area under the ROC for carotid FTc to predict hypotension after induction was 0.876 [95% confidence interval (CI) 0.800-0.952, P <0.001]. The optimal cut-off value was 334.95 ms (sensitivity of 87.20%; specificity of 82.20%). The logistic regression analysis revealed that carotid FTc is an independent predictor for post-induction hypotension in elderly patients. The incidence of post-induction hypotension was significantly lower ( P <0.001) in patients with carotid FTc less than 334.95 ms who received perioperative fluid therapy (35.71%) compared to those who did not (92.31%).

CONCLUSIONS

Carotid FTc combined with the perioperative fluid therapy could significantly reduce the incidence of hypotension after the induction of general anesthesia in elderly patients.

Safety and Feasibility of Intraoperative High PEEP Titrated to the Lowest Driving Pressure (ΔP)-Interim Analysis of DESIGNATION

Uncertainty remains about the best level of intraoperative positive end-expiratory pressure (PEEP). An ongoing RCT ('DESIGNATION') compares an 'individualized high PEEP' strategy ('iPEEP')-titrated to the lowest driving pressure (ΔP) with recruitment maneuvers (RM), with a 'standard low PEEP' strategy ('low PEEP')-using 5 cm H2O without RMs with respect to the incidence of postoperative pulmonary complications. This report is an interim analysis of safety and feasibility. From September 2018 to July 2022, we enrolled 743 patients. Data of 698 patients were available for this analysis. Hypotension occurred more often in 'iPEEP' vs. 'low PEEP' (54.7 vs. 44.1%; RR, 1.24 (95% CI 1.07 to 1.44); p < 0.01). Investigators were compliant with the study protocol 285/344 patients (82.8%) in 'iPEEP', and 345/354 patients (97.5%) in 'low PEEP' (p < 0.01). Most frequent protocol violation was missing the final RM at the end of anesthesia before extubation; PEEP titration was performed in 99.4 vs. 0%; PEEP was set correctly in 89.8 vs. 98.9%. Compared to 'low PEEP', the 'iPEEP' group was ventilated with higher PEEP (10.0 (8.0-12.0) vs. 5.0 (5.0-5.0) cm H2O; p < 0.01). Thus, in patients undergoing general anesthesia for open abdominal surgery, an individualized high PEEP ventilation strategy is associated with hypotension. The protocol is feasible and results in clear contrast in PEEP. DESIGNATION is expected to finish in late 2023.

The Role of Intraoperative and Early Postoperative Blood Pressure Variations, Fluid Balance and Inotropics in Fibula Free Flap Head and Neck Reconstruction: A Retrospective Analysis

BACKGROUND

In head and neck reconstructive surgery, postoperative complications are a well-known concern.

METHODS

We examined 46 patients who underwent ablative surgery and received fibula free flap reconstruction. The main focus was to assess the influence of intraoperative blood pressure fluctuations and the administration of inotropic drugs on complications, either related to the flap or systemic, serving as the primary endpoint.

RESULTS

Utilizing logistic regression models, we identified that intraoperative mean arterial blood pressure (MAP) drops did not correlate with the occurrence of either flap-related complications (MAP < 70, p = 0.79; MAP < 65, p = 0.865; MAP < 60, p = 0.803; MAP < 55, p = 0.937) or systemic medical complications (MAP < 70, p = 0.559; MAP < 65, p = 0.396; MAP < 60, p = 0.211; MAP < 55, p = 0.936). The occurrence of flap-related complications significantly increased if a higher dosage of dobutamine was administered (median 27.5 (IQR 0-47.5) vs. 62 (38-109) mg, p = 0.019) but not if norepinephrine was administered (p = 0.493). This correlation was especially noticeable given the uptick in complications associated with fluid overload (3692 (3101-4388) vs. 4859 (3555-6216) mL, p = 0.026).

CONCLUSION

Intraoperative and immediate postoperative blood pressure fluctuations are common but are not directly associated with flap-related complications; however, dobutamine application as well as fluid overload may impact flap-specific complications.

Continuous Noninvasive Blood Pressure Measurement With "ClearSight" Compared to Standard Intermittent Blood Pressure Measurement in Patients With Peripheral Arterial Disease. Are Potential Differences Influenced by Phenylephrine or Dobutamine?

OBJECTIVES

To investigate the agreement between continuous noninvasive blood pressure measurement with the ClearSight system (cNIBP-CS) and standard intermittent noninvasive blood pressure measurement (iNIBP) in patients with peripheral arterial disease (PAD). Additionally, the influence of vasoactive medication on potential measurement differences was assessed.

DESIGN

A secondary analysis of a randomized controlled trial.

SETTING

At a university hospital.

PARTICIPANTS

Thirty-four patients with PAD undergoing percutaneous transluminal angioplasty of the lower limbs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Continuous noninvasive blood pressures were measured with the "ClearSight" system and compared to standard iNIBPs. Bland-Altman analysis revealed a mean bias of 13 mmHg (±15) between cNIBP-CS and iNIBP, with 95% limits of agreement (LOA) ranging from -17 to 42 mmHg. When comparing both medication groups, a similar mean bias was found for phenylephrine and dobutamine (12 mmHg [±13] and 13 mmHg [±13], respectively).

CONCLUSION

In this study, in patients with PAD, cNIBP-CS showed an underestimation of blood pressure compared to iNIBP in phenylephrine- and dobutamine-treated patients. Compared to previous studies, a larger bias and wider 95% LOA were found.

Intraoperative hypotension affects postoperative acute kidney injury depending on the invasiveness of abdominal surgery: A retrospective cohort study

Intraoperative hypotension (IOH) or highly invasive surgery adversely affects postoperative clinical outcomes. It is, however, unclear whether IOH affects postoperative acute kidney injury (AKI) depending on the invasiveness of abdominal surgery. We speculated that IOH in highly invasive abdominal surgery is a significant risk factor for postoperative AKI. We retrospectively reviewed the data of 448 patients who underwent abdominal surgery. Patients were divided into 3 groups: highly (such as pancreaticoduodenectomy and hepatectomy), moderately (open abdominal surgery), and minimally (laparoscopic surgery) invasive surgeries. The association between the time-weighted average (TWA) of mean arterial pressure (MAP) values (≤60 and ≤ 55 mm Hg) and AKI occurrences in each group was assessed. Postoperative AKI occurred after highly, moderately, and minimally invasive surgeries in 33 of 222 (14.9%), 14 of 110 (12.7%), and 12 of 116 (10.3%) cases, respectively (P = .526). The median [interquartile range] of TWA-MAP ≤ 60 mm Hg, as an IOH parameter, was 0.94 [0.33-2.08] mm Hg in highly, 0.54 [0.16-1.46] mm Hg in moderately, and 0.14 [0.03-0.57] mm Hg in minimally invasive surgeries (P < 0001). In addition, there was a significant association between TWA-MAP and AKI in highly invasive surgery, unlike in moderately and minimally invasive surgery, with adjusted odds ratios (95% confidence interval) for TWA-MAP ≤ 60 and ≤ 55 mm Hg associated with AKI of 1.23 [1.00-1.52] (P = .049) and 1.55 [1.02-2.36] (P = .041), respectively. Intraoperative MAP ≤ 60 mm Hg in highly invasive abdominal surgery is associated with postoperative AKI, compared to moderately and minimally invasive surgeries. Additionally, low MAP thresholds in highly invasive surgery increase postoperative AKI risk.

Bibliometric and visual analysis of intraoperative hypotension from 2004 to 2022

Background

Intraoperative hypotension (IOH) is a common complication occurring in surgical practice. This study aims to comprehensively review the collaboration and impact of countries, institutions, authors, journals, keywords, and critical papers on intraoperative hypotension from the perspective of bibliometric, and to evaluate the evolution of knowledge structure clustering and identify research hotspots and emerging topics.

Methods

Articles and reviews related to IOH published from 2004 to 2022 were retrieved from the Web of Science Core Collection. Bibliometric analyses and visualization were conducted on Excel, CiteSpace, VOSviewer, and Bibliometrix (R-Tool of R-Studio).

Results

A total of 1,784 articles and reviews were included from 2004 to 2022. The number of articles on IOH gradually increased in the past few years, and peaked in 2021. These publications were chiefly from 1,938 institutions in 40 countries, led by America and China in publications. Sessler Daniel I published the most papers and enjoyed the highest number of citations. Analysis of the journals with the most outputs showed that most journals concentrated on perioperative medicine and clinical anesthesiology. Delirium, acute kidney injury and vasoconstrictor agents are the current and developing research hotspots. The keywords "Acute kidney injury", "postoperative complication", "machine learning", "risk factors" and "hemodynamic instability" may also become new trends and focuses of the near future research.

Conclusion

This study uses bibliometrics and visualization methods to comprehensively review the research on intraoperative hypotension, which is helpful for scholars to better understand the dynamic evolution of IOH and provide directions for future research.

Pleth variability index during preoxygenation could predict anesthesia-induced hypotension: A prospective, observational study

STUDY OBJECTIVE

To determine whether changes in the pleth variability index (PVi) during preoxygenation with forced ventilation for 1 min could predict anesthesia-induced hypotension.

DESIGN

Prospective, observational study.

SETTING

A tertiary teaching hospital.

PATIENTS

Ninety-six patients who underwent general anesthesia using total intravenous anesthesia were enrolled.

INTERVENTIONS

Upon the patient's arrival at the preoperative waiting area, a PVi sensor was affixed to their fourth fingertip. For preoxygenation, forced ventilation of 8 breaths/min in a 1:2 inspiratory-expiratory ratio was conducted using the guidance of an audio file. One minute after preoxygenation, anesthetic administration was initiated. Blood pressure was measured for the next 15 min.

MEASUREMENTS

We calculated the difference (dPVi) and percentage of change (%PVi) between the PVi values immediately before and after forced ventilation. Anesthesia-induced hypotension was defined as a mean arterial pressure of <60 mmHg within 15 min after the infusion of anesthetics.

MAIN RESULTS

Overall, 87 patients were included in the final analysis. Anesthesia-induced hypotension occurred in 31 (35.6%) of the 87 patients. Receiver operating characteristic curve analyses identified a cut-off value of -2 for dPVi, with an area under the curve of 0.691 (95% confidence interval [CI], 0.564-0.818; P < 0.001) and a cut-off value of -7.6% for %PVi, with an area under the curve of 0.711 (95% CI, 0.589-0.832; P < 0.001). Further, multivariate logistic regression analysis showed that a low %PVi with an odds ratio of 9.856 (95% CI, 3.131-31.032; P < 0.001) was a significant determinant of anesthesia-induced hypotension.

CONCLUSIONS

Hypotension frequently occurs during general anesthesia induction and can impact outcomes. Additionally, the percentage change in the PVi before and after preoxygenation using deep breathing can be used to predict anesthesia-induced hypotension.

Incorporating intraoperative blood pressure time-series variables to assist in prediction of acute kidney injury after type a acute aortic dissection repair: an interpretable machine learning model

BACKGROUND

Acute kidney injury (AKI) is a common and serious complication after the repair of Type A acute aortic dissection (TA-AAD). However, previous models have failed to account for the impact of blood pressure fluctuations on predictive performance. This study aims to develop machine learning (ML) models combined with intraoperative medicine and blood pressure time-series data to improve the accuracy of early prediction for postoperative AKI risk.

METHODS

Indicators reflecting the duration and depth of hypotension were obtained by analyzing continuous mean arterial pressure (MAP) monitored intraoperatively with multiple thresholds (<65, 60, 55, 50) set in the study. The predictive features were selected by logistic regression and the least absolute shrinkage and selection operator (LASSO), and 4 ML models were built based on the above features. The performance of the models was evaluated by area under receiver operating characteristic curve (AUROC), calibration curve and decision curve analysis (DCA). Shapley additive interpretation (SHAP) was used to explain the prediction models.

RESULTS

Among the indicators reflecting intraoperative hypotension, 65 mmHg showed a statistically superior difference to other thresholds in patients with or without AKI (p < .001). Among 4 models, the extreme gradient boosting (XGBoost) model demonstrated the highest AUROC: 0.800 (95% 0.683-0.917) and sensitivity: 0.717 in the testing set and was verified the best-performing model. The SHAP summary plot indicated that intraoperative urine output, cumulative time of mean arterial pressure lower than 65 mmHg outside cardiopulmonary bypass (OUT_CPB_MAP_65 time), autologous blood transfusion, and smoking were the top 4 features that contributed to the prediction model.

CONCLUSION

With the introduction of intraoperative blood pressure time-series variables, we have developed an interpretable XGBoost model that successfully achieve high accuracy in predicting the risk of AKI after TA-AAD repair, which might aid in the perioperative management of high-risk patients, particularly for intraoperative hemodynamic regulation.

Intraoperative hypotension in noncardiac surgery patients with chronic beta-blocker therapy: A matched cohort analysis

STUDY OBJECTIVE

To explore the incidence of intraoperative hypotension in patients with chronic beta-blocker therapy, expressed as time spent, area and time-weighted average under predefined mean arterial pressure thresholds.

DESIGN

Retrospective analysis of a prospective observational cohort registry.

SETTING

Patients ≥60 years undergoing intermediate- to high-risk noncardiac surgery with routine postoperative troponin measurements on the first three days after surgery.

PATIENTS

1468 matched sets of patients (1:1 ratio with replacement) with and without chronic beta-blocker treatment.

INTERVENTIONS

None.

MEASUREMENTS

The primary outcome was the exposure to intraoperative hypotension in beta-blocker users vs. non-users. Time spent, area and time-weighted average under predefined mean arterial pressure thresholds (55-75 mmHg) were calculated to express the duration and severity of exposure. Secondary outcomes included incidence of postoperative myocardial injury and thirty-day mortality, myocardial infarction (MI) and stroke. Furthermore, analyses for patient subgroup and beta-blocker subtype were conducted.

MAIN RESULTS

In patients with chronic beta-blocker therapy, no increased exposure to intraoperative hypotension was observed for all characteristics and thresholds calculated (all P > .05). Beta-blocker users had lower heart rate before, during and after surgery (70 vs. 74, 61 vs. 65 and 68 vs. 74 bpm, all P < .001, respectively). Postoperative myocardial injury (13.6% vs. 11.6%, P = .269) and thirty-day mortality (2.5% vs. 1.4%, P = .055), MI (1.4% vs. 1.5%, P = .944) and stroke (1.0% vs 0.7%, P =  .474) rates were comparable. The results were consistent in subtype and subgroup analyses.

CONCLUSIONS

In this matched cohort analysis, chronic beta-blocker therapy was not associated with increased exposure to intraoperative hypotension in patients undergoing intermediate- to high-risk noncardiac surgery. Furthermore, differences in patient subgroups and postoperative adverse cardiovascular events as a function of treatment regimen could not be demonstrated.

Handling Severe Intraoperative Hemorrhage and Avoiding Iatrogenic Stroke During Brain Tumor Surgery: Techniques for Prevention of Hemorrhagic and Ischemic Complications

BACKGROUND

Nationwide databases show that iatrogenic stroke and postoperative hematoma are among the commonest complications in brain tumor surgery, with a 10-year incidence of 16.3/1000 and 10.3/1000, respectively. However, techniques for handling severe intraoperative hemorrhage and dissecting, preserving, or selectively obliterating vessels traversing the tumor are sparse in the literature.

METHODS

Records of the senior author's intraoperative techniques during severe haemorrhage and vessel preservation were reviewed and analyzed. Intraoperative media demonstrations of key techniques were collected and edited. In parallel, a literature search investigating technique description in handling severe intraoperative hemorrhage and vessel preservation in tumor surgery was undertaken. Histologic, anesthetic, and pharmacologic prerequisites of significant hemorrhagic complications and hemostasis were analyzed.

RESULTS

The senior author's techniques for arterial and venous skeletonization, temporary clipping with cognitive or motor mapping, and ION monitoring were categorized. Vessels interfacing with tumor are labeled intraoperatively as supplying/draining the tumor, or traversing en passant, while supplying/draining functional neural tissue. Intraoperative techniques of differentiation were analyzed and illustrated. Literature search found 2 vascular-related complication domains in tumor surgery: perioperative management of excessively vascular intraparenchymal tumors and lack of intraoperative techniques and decision processes for dissecting and preserving vessels interfacing or traversing tumors.

CONCLUSIONS

Literature searches showed a dearth of complication-avoidance techniques in tumor-related iatrogenic stroke, despite its high prevalence. A detailed preoperative and intraoperative decision process was provided along with a series of case illustrations and intraoperative videos showing the techniques required to reduce intraoperative stroke and associated morbidity addressing a void in complication avoidance of tumor surgery.

Diagnostic Efficacy of Carotid Ultrasound for Predicting the Risk of Perioperative Hypotension or Fluid Responsiveness: A Meta-Analysis

Despite the acceptance of carotid ultrasound for predicting patients' fluid responsiveness in critical care and anesthesia, its efficacy for predicting hypotension and fluid responsiveness remains unclear in the perioperative setting. Electronic databases were searched from inception to May 2023 to identify observational studies focusing on the use of corrected blood flow time (FTc) and respirophasic variation in carotid artery blood flow peak velocity (ΔVpeak) for assessing the risks of hypotension and fluid responsiveness. Using FTc as a predictive tool (four studies), the analysis yielded a pooled sensitivity of 0.82 (95% confidence interval (CI): 0.72 to 0.89) and specificity of 0.94 (95% CI: 0.88 to 0.97) for the risk of hypotension (area under curve (AUC): 0.95). For fluid responsiveness, the sensitivity and specificity of FTc were 0.79 (95% CI: 0.72 to 0.84) and 0.81 (95% CI: 0.75 to 0.86), respectively (AUC: 0.87). In contrast, the use of ΔVpeak to predict the risk of fluid responsiveness showed a pooled sensitivity of 0.76 (95% CI: 0.63 to 0.85) and specificity of 0.74 (95% CI: 0.66 to 0.8) (AUC: 0.79). The current meta-analysis provides robust evidence supporting the high diagnostic accuracy of FTc in predicting perioperative hypotension and fluid responsiveness, which requires further studies for verification.

The incidence of hypotension during general anesthesia: a single-center study at a university hospital

BACKGROUND

Although intraoperative hypotension (IOH) has been emerging as a serious concern during general anesthesia, the incidence of IOH has not been demonstrated clearly in the Japanese population.

METHODS

This single-center retrospective study investigated the incidence and the characteristics of IOH in non-cardiac surgery at a university hospital. IOH was defined as at least one fall of MAP during general anesthesia, which was categorized into the following groups: mild (65 to < 75 mmHg), moderate (55 to < 65 mmHg), severe (45 to < 55 mmHg), and very severe (< 45 mmHg). The incidence of IOH was calculated as a percentage of the number of events to the total anesthesia cases. Logistic regression analysis was performed to examine factors affecting IOH.

RESULTS

Eleven thousand two hundred ten cases out of 13,226 adult patients were included in the analysis. We found moderate to very severe hypotension occurred in 86.3% of the patients for at least 1 to 5 min, and 48.5% experienced severe or very severe hypotension. The results of the logistic regression analysis indicated female gender, vascular surgery, American Society of Anesthesiologists physical status classification (ASA-PS) 4 or 5 in emergency surgery, and the combination with the epidural block (EDB) were significant factors of IOH.

CONCLUSIONS

IOH during general anesthesia was very frequent in the Japanese population. Female gender, vascular surgery, ASA-PA 4 or 5 in emergency surgery, and the combination with EDB were independent risk factors associated with IOH. However, the association with patient outcomes were not elucidated.

Association of intraoperative hypotension and severe postoperative complications during non-cardiac surgery in adult patients: A systematic review and meta-analysis

Background

Intraoperative hypotension (IOH) is a common side effect of non-cardiac surgery that might induce poor postoperative outcomes. The relationship between the IOH and severe postoperative complications is still unclear. Thus, we summarized the existing literature to evaluate whether IOH contributes to developing severe postoperative complications during non-cardiac surgery.

Methods

We conducted a comprehensive search of PubMed, Embase, Cochrane Library, Web of Science, and the CBM from inception to 15 September 2022. The primary outcomes were 30-day mortality, acute kidney injury (AKI), major adverse cardiac events (myocardial injury or myocardial infarction), postoperative cognitive dysfunction (POCD), and postoperative delirium (POD). Secondary outcomes included surgical-site infection (SSI), stroke, and 1-year mortality.

Results

72 studies (3 randomized; 69 non-randomized) were included in this study. Low-quality evidence showed IOH resulted in an increased risk of 30-day mortality (OR, 1.85; 95% CI, 1.30-2.64; P < .001), AKI (OR, 2.69; 95% CI, 2.15-3.37; P < .001), and stroke (OR, 1.33; 95% CI, 1.21-1.46; P < .001) after non-cardiac surgery than non-IOH. Very low-quality evidence showed IOH was associated with a higher risk of myocardial injury (OR, 2.00; 95% CI, 1.17-3.43; P = .01), myocardial infarction (OR, 2.11; 95% CI, 1.41-3.16; P < .001), and POD (OR, 2.27; 95% CI, 1.53-3.38; P < .001). Very low-quality evidence showed IOH have a similar incidence of POCD (OR, 2.82; 95% CI, 0.83-9.50; P = .10) and 1-year-mortality (OR, 1.66; 95% CI, 0.65-4.20; P = .29) compared with non-IOH in non-cardiac surgery.

Conclusion

Our results suggest IOH was associated with an increased risk of severe postoperative complications after non-cardiac surgery than non-IOH. IOH is a potentially avoidable hazard that should be closely monitored during non-cardiac surgery.

A framework for perioperative care for lower extremity vascular bypasses: A Consensus Statement by the Enhanced Recovery after Surgery (ERAS®) Society and Society for Vascular Surgery

The Society for Vascular Surgery and the Enhanced Recovery After Surgery (ERAS) Society formally collaborated and elected an international, multi-disciplinary panel of experts to review the literature and provide evidence-based suggestions for coordinated perioperative care for patients undergoing infrainguinal bypass surgery for peripheral artery disease. Structured around the ERAS core elements, 26 suggestions were made and organized into preadmission, preoperative, intraoperative, and postoperative sections.

Perioperative strategies to reduce risk of myocardial injury after non-cardiac surgery (MINS): A narrative review

Myocardial injury is a frequent complication of surgical patients after having non-cardiac surgery that is strongly associated with perioperative mortality. While intraoperative anesthesia-related deaths are exceedingly rare, about 1% of patients undergoing non-cardiac surgery die within the first 30 postoperative days. Given the number of surgeries performed annually, death following surgery is the second leading cause of death in the United States. Myocardial injury after non-cardiac surgery (MINS) is defined as an elevation in troponin concentrations within 30 days postoperatively. Although typically asymptomatic, patients with MINS suffer myocardial damage and have a 10% risk of death within 30 days after surgery and excess risks of mortality that persist during the first postoperative year. Many factors for the development of MINS are non-modifiable, such as preexistent coronary artery disease. Preventive measures, systematic approaches to surveillance and treatment standards are still lacking, however many factors are modifiable and should be considered in clinical practice: the importance of hemodynamic control, adequate oxygen supply, metabolic homeostasis, the use of perioperative medications such as statins, anti-thrombotic agents, beta-blockers, or anti-inflammatory agents, as well as some evidence regarding the choice of sedative and analgesic for anesthesia are discussed. Also, as age and complexity in comorbidities of the surgical patient population increase, there is an urgent need to identify patients at risk for MINS and develop prevention and treatment strategies. In this review, we provide an overview of current screening standards and promising preventive options in the perioperative setting and address knowledge gaps requiring further investigation.

Intraoperative Hypotension Prediction—A Proactive Perioperative Hemodynamic Management—A Literature Review

Intraoperative hypotension (IH) is a frequent phenomenon affecting a substantial number of patients undergoing general anesthesia. The occurrence of IH is related to significant perioperative complications, including kidney failure, myocardial injury, and even increased mortality. Despite advanced hemodynamic monitoring and protocols utilizing goal directed therapy, our management is still reactive; we intervene when the episode of hypotension has already occurred. This literature review evaluated the Hypotension Prediction Index (HPI), which is designed to predict and reduce the incidence of IH. The HPI algorithm is based on a machine learning algorithm that analyzes the arterial pressure waveform as an input and the occurrence of hypotension with MAP <65 mmHg for at least 1 min as an output. There are several studies, both retrospective and prospective, showing a significant reduction in IH episodes with the use of the HPI algorithm. However, the level of evidence on the use of HPI remains very low, and further studies are needed to show the benefits of this algorithm on perioperative outcomes.

Photoplethysmography waveform analysis for classification of vascular tone and arterial blood pressure: Study based on neural networks

BACKGROUND

To test whether a Shallow Neural Network (S-NN) can detect and classify vascular tone dependent changes in arterial blood pressure (ABP) by advanced photopletysmographic (PPG) waveform analysis.

METHODS

PPG and invasive ABP signals were recorded in 26 patients undergoing scheduled general surgery. We studied the occurrence of episodes of hypertension (systolic arterial pressure (SAP) >140 mmHg), normotension and hypotension (SAP < 90 mmHg). Vascular tone according to PPG was classified in two ways: 1) By visual inspection of changes in PPG waveform amplitude and dichrotic notch position; where Classes I-II represent vasoconstriction (notch placed >50% of PPG amplitude in small amplitude waves), Class III normal vascular tone (notch placed between 20-50% of PPG amplitude in normal waves) and Classes IV-V-VI vasodilation (notch <20% of PPG amplitude in large waves). 2) By an automated analysis, using S-NN trained and validated system that combines seven PPG derived parameters.

RESULTS

The visual assessment was precise in detecting hypotension (sensitivity 91%, specificity 86% and accuracy 88%) and hypertension (sensitivity 93%, specificity 88% and accuracy 90%). Normotension presented as a visual Class III (III-III) (median and 1st-3rd quartiles), hypotension as a Class V (IV-VI) and hypertension as a Class II (I-III); all p < .0001. The automated S-NN performed well in classifying ABP conditions. The percentage of data with correct classification by S-ANN was 83% for normotension, 94% for hypotension, and 90% for hypertension.

CONCLUSIONS

Changes in ABP were correctly classified automatically by S-NN analysis of the PPG waveform contour.

Ultrasound-guided anterior iliopsoas muscle space block effectively reduces intraoperative hypotension in elderly adults undergoing hip surgery: A randomised controlled trial

Background

Hypotension often occurs during hip surgery in elderly adults with conventional posterior lumbosacral plexus block.

Purpose

We conducted a randomised controlled trial to determine if simple iliopsoas space block can lower the incidence of intraoperative hypotension (IOH) and provide sufficient perioperative pain relief during hip fracture surgery in elderly adults.

Methods

Patients undergoing surgery for elderly hip fracture were randomised to receive either an anterior iliopsoas space block with a lateral femoral cutaneous nerve block or a posterior lumbosacral plexus block. The primary outcome was a composite measure of IOH incidence comprising frequency, absolute and relative hypotension durations.

Results

Compared to the posterior group, the iliopsoas space block group had a decreased median frequency of IOH [1.09 (0-2. 14) vs. 3 (1.6-4.8), p = 0.001, respectively] along with lower absolute [5 (0-10) min] and relative [minutes below systolic blood pressure of 100 mmHg in % of total anaesthesia time, 6.67 (0-7.65)] duration of IOH compared to the posterior group [35 (10-45) min, p = 0.008; 37.6 (12.99-66.18), p = 0.004, respectively]. The median pain levels in the post-anaesthesia care unit and median intraoperative sufentanil usage were comparable between the iliopsoas space group [2 (1-3); 8 (6-10) μg] and posterior group [1 (0-3); 5 (5-8) μg]. Thermal imaging revealed that the limb injected with the iliopsoas space block had a higher skin temperature than the unblocked limb in the sacral plexus innervated region.

Conclusion

A single iliopsoas space block lowers the IOH incidence and provides comparable perioperative analgesia to conventional lumbosacral plexus block.

Clinical Trial Registration

Trial registration at www.chictr.org.cn (ChiCTR2100051394); registered 22 September 2021.

Comparison of hemodynamics during induction of general anesthesia with remimazolam and target-controlled propofol in middle-aged and elderly patients: a single-center, randomized, controlled trial

BACKGROUND

Remimazolam confers a lower risk of hypotension than propofol. However, no studies have compared the efficacy of remimazolam and propofol administered using target-controlled infusion (TCI). This study aimed to investigate hemodynamic effects of remimazolam and target-controlled propofol in middle-aged and elderly patients during the induction of anesthesia.

METHODS

Forty adults aged 45-80 years with the American Society of Anesthesiologists Physical Status 1-2 were randomly assigned to remimazolam or propofol group (n = 20 each). Patients received either remimazolam (12 mg/kg/h) or propofol (3 μg/mL, TCI), along with remifentanil for inducing anesthesia. We recorded the blood pressure, heart rate (HR), and estimated continuous cardiac output (esCCO) using the pulse wave transit time. The primary outcome was the maximum change in mean arterial pressure (MAP) after induction. Secondary outcomes included changes in HR, cardiac output (CO), and stroke volume (SV).

RESULTS

MAP decreased after induction of anesthesia in both groups, without significant differences between the groups (- 41.1 [16.4] mmHg and - 42.8 [10.8] mmHg in remimazolam and propofol groups, respectively; mean difference: 1.7 [95% confidence interval: - 8.2 to 4.9]; p = 0.613). Furthermore, HR, CO, and SV decreased after induction in both groups, without significant differences between the groups. Remimazolam group had significantly shorter time until loss of consciousness than propofol group (1.7 [0.7] min and 3.5 [1.7] min, respectively; p < 0.001). However, MAP, HR, CO, and SV were not significantly different between the groups despite adjusting time until loss of consciousness as a covariate. Seven (35%) and 11 (55%) patients in the remimazolam and propofol groups, respectively, experienced hypotension (MAP < 65 mmHg over 2.5 min), without significant differences between the groups (p = 0.341).

CONCLUSIONS

Hemodynamics were not significantly different between remimazolam and target-controlled propofol groups during induction of anesthesia. Thus, not only the choice but also the dose and usage of anesthetics are important for hemodynamic stability while inducing anesthesia. Clinicians should monitor hypotension while inducing anesthesia with remimazolam as well as propofol.

TRIAL REGISTRATION

UMIN-CTR (UMIN000045612).

Association between hypotension and myocardial injury in patients with severe trauma

PURPOSE

During resuscitation of patients with severe trauma, guidelines recommend permissive hypotension prior to surgical bleeding control. However, hypotension may be associated with reduced organ perfusion and multiple organ dysfunction, e.g. myocardial injury. The association between hypotension and myocardial injury in trauma patients is underexplored. We hypothesized that hypotension is associated with myocardial injury in this population.

MATERIALS AND METHODS

This retrospective study included patients ≥ 18 years suffering from severe trauma [defined as Injury Severity Score (ISS) ≥ 16] that were treated in the emergency department resuscitation room between 2016 and 2019. Primary endpoint was the incidence of myocardial injury defined as high-sensitive troponin T > 14 ng/l. Main exposure was the duration of arterial hypotension during resuscitation period defined as mean arterial pressure < 65 mmHg.

RESULTS

Out of 368 patients screened, 343 were analyzed (73% male, age: 55 ± 21, ISS: 28 ± 12). Myocardial injury was detected in 143 (42%) patients. Overall in-hospital mortality was 26%. Multivariate binary logistic regression with forced entry of nine predefined covariables revealed an odds ratio of 1.29 [95% confidence interval 1.16-1.44]; p = 0.012) for the association between the duration of hypotension and myocardial injury.

CONCLUSION

The duration of hypotension during resuscitation period is independently associated with the incidence of myocardial injury in patients with severe trauma.

High versus low blood pressure targets for cardiac surgery while on cardiopulmonary bypass

BACKGROUND

Cardiac surgery is performed worldwide. Most types of cardiac surgery are performed using cardiopulmonary bypass (CPB). Cardiac surgery performed with CPB is associated with morbidities. CPB needs an extracorporeal circulation that replaces the heart and lungs, and performs circulation, ventilation, and oxygenation of the blood. The lower limit of mean blood pressure to maintain blood flow to vital organs increases in people with chronic hypertension. Because people undergoing cardiac surgery commonly have chronic hypertension, we hypothesised that maintaining a relatively high blood pressure improves desirable outcomes among the people undergoing cardiac surgery with CPB.

OBJECTIVES

To evaluate the benefits and harms of higher versus lower blood pressure targets during cardiac surgery with CPB.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search of databases was November 2021 and trials registries in January 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing a higher blood pressure target (mean arterial pressure 65 mmHg or greater) with a lower blood pressure target (mean arterial pressure less than 65 mmHg) in adults undergoing cardiac surgery with CPB.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were 1. acute kidney injury, 2. cognitive deterioration, and 3. all-cause mortality. Secondary outcomes were 4. quality of life, 5. acute ischaemic stroke, 6. haemorrhagic stroke, 7. length of hospital stay, 8. renal replacement therapy, 9. delirium, 10. perioperative transfusion of blood products, and 11. perioperative myocardial infarction. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included three RCTs with 737 people compared a higher blood pressure target with a lower blood pressure target during cardiac surgery with CPB. A high blood pressure target may result in little to no difference in acute kidney injury (risk ratio (RR) 1.30, 95% confidence interval (CI) 0.81 to 2.08; I² = 72%; 2 studies, 487 participants; low-certainty evidence), cognitive deterioration (RR 0.82, 95% CI 0.45 to 1.50; I² = 0%; 2 studies, 389 participants; low-certainty evidence), and all-cause mortality (RR 1.33, 95% CI 0.30 to 5.90; I² = 49%; 3 studies, 737 participants; low-certainty evidence). No study reported haemorrhagic stroke. Although a high blood pressure target may increase the length of hospital stay slightly, we found no differences between a higher and a lower blood pressure target for the other secondary outcomes. We also identified one ongoing RCT which is comparing a higher versus a lower blood pressure target among the people who undergo cardiac surgery with CPB.

AUTHORS' CONCLUSIONS

A high blood pressure target may result in little to no difference in patient outcomes including acute kidney injury and mortality. Given the wide CIs, further studies are needed to confirm the efficacy of a higher blood pressure target among those who undergo cardiac surgery with CPB.

The use of artificial intelligence and machine learning monitoring to safely administer a fluid-restrictive goal-directed treatment protocol to minimize the risk of transfusion during major spine surgery of a Jehovah’s Witness: a case report

Background

The Hypotension Prediction Index (HPI) displays an innovative monitoring tool which predicts intraoperative hypotension before its onset.

Case presentation

We report the case of an 84-year-old Caucasian woman undergoing major spinal surgery with no possibility for the transfer of blood products given her status as a Jehovah’s Witness. The hemodynamic treatment algorithm we employed was based on HPI and resulted in a high degree of hemodynamic stability during the surgical procedure. Further, the patient was not at risk for either hypo- or hypervolemia, conditions which might have caused dilution anemia. By using HPI as a tool for patient blood management, it was possible to reduce the incidence of intraoperative hypotension to a minimum.

Conclusions

In sum, this HPI-based treatment algorithm represents a useful application for the treatment of complex anesthesia and perioperative patient blood management. It is a simple but powerful extension of standard monitoring for the prevention of intraoperative hypotension.

Association of anesthesia and analgesia with long-term mortality after hip fracture surgery: an analysis of the Australian and New Zealand hip fracture registry

Introduction

Hip fractures are a common frailty injury affecting a vulnerable geriatric population. It is debated if anesthetic and analgesic techniques are associated with altered risk for outcomes in hip fracture patients. This study aimed to determine the association of anesthesia and regional analgesia with all cause 12-month mortality and even longer-term mortality after hip fracture surgery in Australia and New Zealand.

Methods

Data from the Australian and New Zealand Hip Fracture Registry collected from 2016 to 2018, with a minimum follow-up of 12 months, were reviewed. Anesthesia type and use of regional nerve blocks were investigated. The primary outcome was all cause 12-month mortality.

Results

12-month mortality was 30.6% (n=5410) in a total of 17,635 patients. There was no difference in 12-month mortality between patients who received spinal or general anesthesia (p=0.238). The administration of a combination of general and spinal anesthesia for surgery to repair the fracture was an independent predictor of higher 12-month mortality (unadjusted complete case HR=1.17 (95% CI 1.04 to 1.31); p<0.001). Nerve blocks performed in both the emergency department (ED) and the operating theater (OT) were associated with reduced long-term mortality (median follow-up 21 months) with an unimputed unadjusted HR=0.86 (95% CI 0.77 to 0.96; p=0.043).

Conclusion

There was no difference in the association of 12-month mortality between general and spinal anesthesia in patients undergoing hip fracture surgery. However, there was an association with a higher risk of 12-month mortality in patients who received both general and spinal anesthesia for the same surgery. Patients who received a regional nerve block in both the ED and the OT had a lower association of 12-month and longer-term mortality risk. The reasons for these findings remain unknown and should be the subject of further research investigation.

Impact of hemodynamic instability during cytoreductive surgery on survival in high-grade serous ovarian carcinoma

Background

To evaluate the impact of intraoperative hypotension and hemodynamic instability on survival outcomes in patients with high-grade serous ovarian carcinoma (HGSOC).

Methods

We retrospectively identified patients with HGSOC, who underwent primary or interval debulking surgery between August 2013 and December 2019. We collected anesthesia-related variables, including the arterial blood pressure measurements (at 1-min intervals) during the surgery of patients. The cumulative duration of mean arterial blood pressure (MAP) readings under 65 mmHg and two performance measurements (median performance error [MDPE] and wobble) were calculated. We investigated associations between the factors indicating hemodynamic instability and prognosis.

Results

In total, 338 patients were included. Based on the cumulative duration of MAP under 65 mmHg, we divided patients into two groups: ≥30 min and <30 min. The progression-free survival (PFS) was worse in the ≥30 min group (n = 107) than the <30 min group (n = 231) (median, 18.2 vs. 23.7 months; P = 0.014). In multivariate analysis adjusting for confounders, a duration of ≥30 min of MAP under 65 mmHg was identified as an independent poor prognostic factor for PFS (adjusted HR, 1.376; 95% CI, 1.035–1.830; P = 0.028). Shorter PFS was observed in the group with a MDPE <−4.0% (adjusted HR, 1.351; 95% CI, 1.024–1.783; P = 0.033) and a wobble ≥7.5% (adjusted HR, 1.445; 95% CI, 1.100–1.899; P = 0.008). However, no differences were observed in overall survival.

Conclusion

This study suggests that the three intraoperative variables for hemodynamic instability, cumulative duration of MAP <65 mmHg, MDPE, and wobble, might be novel prognostic biomarkers for disease recurrence in patients with HGSOC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10060-1.

Associations between intraoperative hypotension, duration of surgery and postoperative myocardial injury after noncardiac surgery: a retrospective single-centre cohort study

BACKGROUND

Studies of intraoperative hypotension typically specify a blood pressure threshold associated with adverse outcomes. Such thresholds are likely to be study-biased, investigator-biased, or both. We hypothesised that a newly developed modelling method without a threshold, which is biologically more plausible than a threshold-based approach, would reveal a continuous association between exposure to intraoperative hypotension and adverse outcomes.

METHODS

Single-centre, retrospective cohort study of subjects ≥60 yr old undergoing noncardiac surgery. We modelled intraoperative hypotension using three different approaches: (1) unweighted, (2) weighted for degree of hypotension (depth), and (3) weighted for duration of hypotension. The primary outcome was myocardial injury, defined as elevated troponin I (>60 ng L^-1) measured during the first 3 days after surgery. The associations between the three models, postoperative myocardial injury, and mortality (secondary outcome) were reported as penalised adjusted odds ratios (ORs) scaled between the 75th and 25th percentiles.

RESULTS

Myocardial injury occurred in 1812/15 452 (12%) procedures, with 554/15 452 (3.6%) procedures resulting in death before discharge from hospital. The unweighted lower blood pressure measure (OR: 0.26, 95% confidence interval [CI]: 0.12-0.53) and the depth-weighted measure (OR: 4.4, 95% CI: 2.6-7.4) were associated with myocardial injury. The duration-weighted measure was not associated with myocardial injury (OR: 0.89, 95% CI: 0.61-1.3). The unweighted measure (OR 0.08, 95% CI: 0.01-0.40) and the depth-weighted measure (OR: 12, 95% CI, 3.8-35) were associated with in-hospital mortality, but not the duration-weighted measure (OR: 1.3, 95% CI: 0.53-3.0).

CONCLUSIONS

Intraoperative hypotension appears to have a graded association with postoperative myocardial injury and mortality, with depth appearing to contribute more than duration.

Microvascular Changes of the Non-surgical Eye after General Anesthesia in Optical Coherence Tomography Angiography

Purpose: To investigate chorioretinal vascular changes in the non-surgical eyes of patients who underwent vitreoretinal surgery under general anesthesia using optical coherence tomography angiography (OCTA).Methods: Data from 40 patients who underwent retinal surgery were retrospectively analyzed. Ophthalmologic examinations (including OCTA) were performed in the morning before and after surgery. The presence of intraoperative hypotension (IOH; mean arterial pressure <70 mmHg) was determined based on medical records. The vessel density of superficial and deep retinal capillary plexus layers, choriocapillaris void features, and thickness of the choroid and retina were quantified after image processing. Associations between retinal OCTA parameters and anesthesia profiles were also assessed.Results: DCP vessel density was increased after general anesthesia (p < 0.05). Among the patients who experienced IOH, there was no statistical difference in chorioretinal vessel parameters before and after general anesthesia. Also, we did not observe a difference in chorioretinal vessel parameters after general anesthesia between healthy patients and patients with chronic disease, including hypertension and diabetes (p > 0.05). The duration of anesthesia and average size of the choriocapillaris void (p < 0.05, r = -0.32), and the intraoperative mean arterial pressure (MAP) fluctuation and DCP, showed statistically significant negative linear correlations (p < 0.05, r = -0.38). The choriocapillaris void size and intraoperative MAP fluctuation also displayed a significant negative correlation (p < 0.05, r = -0.37), while the average size signal void showed a weak positive linear correlation (p < 0.01, r = 0.41; and p < 0.01, r = 0.44, respectively).Conclusions: This is the first study to assess the effects of general anesthesia on chorioretinal vessels using OCTA. The Vessel density of the DCP was significantly increased in the non-surgical eye after total vitrectomy under general anesthesia. Furthermore, we found a correlation between MAP fluctuation and choriocapillaris void features. More studies are needed to confirm and expand on these observations.

Predicting intraoperative hypotension using deep learning with waveforms of arterial blood pressure, electroencephalogram, and electrocardiogram: Retrospective study

To develop deep learning models for predicting Interoperative hypotension (IOH) using waveforms from arterial blood pressure (ABP), electrocardiogram (ECG), and electroencephalogram (EEG), and to determine whether combination ABP with EEG or CG improves model performance. Data were retrieved from VitalDB, a public data repository of vital signs taken during surgeries in 10 operating rooms at Seoul National University Hospital from January 6, 2005, to March 1, 2014. Retrospective data from 14,140 adult patients undergoing non-cardiac surgery with general anaesthesia were used. The predictive performances of models trained with different combinations of waveforms were evaluated and compared at time points at 3, 5, 10, 15 minutes before the event. The performance was calculated by area under the receiver operating characteristic (AUROC), area under the precision-recall curve (AUPRC), sensitivity and specificity. The model performance was better in the model using both ABP and EEG waveforms than in all other models at all time points (3, 5, 10, and 15 minutes before an event) Using high-fidelity ABP and EEG waveforms, the model predicted IOH with a AUROC and AUPRC of 0.935 [0.932 to 0.938] and 0.882 [0.876 to 0.887] at 5 minutes before an IOH event. The output of both ABP and EEG was more calibrated than that using other combinations or ABP alone. The results demonstrate that a predictive deep neural network can be trained using ABP, ECG, and EEG waveforms, and the combination of ABP and EEG improves model performance and calibration.