Intraoperative hypotension is associated with myocardial damage in noncardiac surgery: An observational study

Comparative Analysis of the Hemodynamic Effects of Remimazolam and Propofol During General Anesthesia: A Retrospective Study

PURPOSE

Hypotension is common during anesthesia induction. However, minimal hemodynamic effects of remimazolam anesthesia have been reported. We hypothesized that remimazolam would have weaker hemodynamic effects than would propofol. To test this, we simultaneously evaluated the hemodynamics using the estimated continuous cardiac output (esCCO) system and heart rate variability (HRV) during anesthesia induction.

METHODS

This was a single-center, observational, retrospective study of patients undergoing dental surgery under general anesthesia between 2020 and 2022. Seventy patients were divided into two groups: remimazolam (R group; n=34) and propofol (P group; n=36). The information obtained from the anesthesia records, patient information, esCCO system parameters, and HRV were integrated and analyzed. The percentages of various parameters were set to 100% for the pre-induction phase as the baseline.

RESULTS

The %MAP (noninvasive mean arterial blood pressure) decreased over a narrower range in the R compared to the P group (-17.8% (-26.3%, -11.9%) vs. -22.6% (-32.9%, -17.0%); P=0.039). The %HR (heart rate) increased significantly in the R group and decreased in the P group (+10.7% (+6.5%, +18.6%) vs. -6.5% (-14.5%, +8.4%); P<0.01). The %SVesCCO (stroke volume calculated using the esCCO system) decreased significantly in both groups, but the R group showed a smaller difference compared to the P group (- 5.1% (-7.7%, -2.1%) vs. -10.0% (-13.8%, -5.6%); P<0.01). The rates of change in %LF nu (normalized unit of low frequency) and %HF nu (normalized unit of high frequency) were lower for the R than for the P group, although the difference was not significant (+6.8% (-14.5%, 32.4%) vs. +9.2% (-7.2%, +59.7%), P=0.30; +7.9% (-51.0%, +66.9%) vs. +22.8% (-26.1%, +61.6%), P=0.57).

CONCLUSION

Remimazolam demonstrated a lower MAP reduction rate than propofol. A compensatory increase in HR occurred with a decrease in stroke volume. However, the HR increase was not attributable to the autonomic nervous system.

Efficacy of remimazolam tosilate versus propofol for total intravenous anaesthesia in urological surgery: A randomised clinical trial

BACKGROUND

Remimazolam is a novel ultra-short-acting benzodiazepine sedative that acts on the gamma-aminobutyric acid type A receptor (GABAAR).

OBJECTIVE

To compare the efficacies of remimazolam (RMZ), and propofol (PROP) combined with remifentanil and cisatracurium for total intravenous anaesthesia (TIVA) in patients undergoing urological surgery.

DESIGN

A prospective, single-blind, randomised, noninferiority clinical trial.

SETTING

Single centre from 1 January 2022 to 30 March 2022.

PATIENTS

A total of 146 adult patients undergoing elective urological surgery.

INTERVENTION

Patients were randomly allocated in a 1 : 1 ratio to the PROP or RMZ groups. In the PROP group, anaesthesia was induced with propofol at 100 mg min -1 to reach a bispectral index score (BIS) of 40 to 60. After loss of consciousness (LOC), intravenous fentanyl 3 μg kg -1 was administered, followed by cisatracurium 0.3 mg kg -1 . Patients were intubated 3 min after cisatracurium administration. Anaesthesia was maintained with the combination of propofol (plasma concentration: 2.5 to 4 μg ml -1 ) and remifentanil (plasma concentration: 2.5 to 4 ng ml -1 ). In the RMZ group, anaesthesia was induced with remimazolam tosilate starting at 10 mg kg -1  h -1 to reach a BIS of 40 to 60 and maintained between 0.2 and 2 mg kg -1  h -1 . After LOC, fentanyl and cisatracurium were administered and intubation was performed as in the PROP group. Anaesthesia was maintained with a combination of remimazolam (0.2 to 2 mg kg -1  h -1 ) and remifentanil (plasma concentration: 2.5 to 4 ng ml -1 ).

MAIN OUTCOME MEASURES

The primary outcome was the TIVA success rate. The predefined noninferiority margin considered an absolute difference of 6% in the primary outcome between the groups. The secondary outcomes were vital signs, anaesthesia and surgery characteristics, and adverse events.

RESULTS

All patients completed the trial. The success rates of TIVA with remimazolam and propofol were 100 and 98.6%, respectively. The incidence of hypotension during anaesthesia was lower in the RMZ group (26%) than in the PROP group (46.6%) ( P  = 0.016). The median [IQR] total consumption of ephedrine during anaesthesia was higher in the PROP group 10 [0 to 12.5] mg than in the RMZ group 0 [0 to 10] mg ( P  = 0.0002). The incidence of injection pain was significantly higher in the PROP group (76.7%) than in the RMZ group (0; P  < 0.001). No significant differences in the controllability of the anaesthesia depth, anaesthesia and surgery characteristics, or vital signs were observed between the groups.

CONCLUSION

Remimazolam demonstrated noninferior efficacy to propofol combined with remifentanil and cisatracurium for TIVA in patients undergoing urological surgery.

TRIAL REGISTRATION

Chictr.org.cn, identifier: ChiCTR2100050923.

CLINICAL REGISTRATION

The study was registered in the Chinese Clinical Trial Registry (ChiCTR2100050923, Principal investigator: Xuehai Guan, Date of registration: 8 November 2021, https://www.chictr.org.cn/showproj.html?proj=133466 ).

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.

Multitask Attention-Based Neural Network for Intraoperative Hypotension Prediction

Timely detection and response to Intraoperative Hypotension (IOH) during surgery is crucial to avoid severe postoperative complications. Although several methods have been proposed to predict IOH using machine learning, their performance still has space for improvement. In this paper, we propose a ResNet-BiLSTM model based on multitask training and attention mechanism for IOH prediction. We trained and tested our proposed model using bio-signal waveforms obtained from patient monitoring of non-cardiac surgery. We selected three models (WaveNet, CNN, and TCN) that process time-series data for comparison. The experimental results demonstrate that our proposed model has optimal MSE (43.83) and accuracy (0.9224) compared to other models, including WaveNet (51.52, 0.9087), CNN (318.52, 0.5861), and TCN (62.31, 0.9045), which suggests that our proposed model has better regression and classification performance. We conducted ablation experiments on the multitask and attention mechanisms, and the experimental results demonstrated that the multitask and attention mechanisms improved MSE and accuracy. The results demonstrate the effectiveness and superiority of our proposed model in predicting IOH.

Intraoperative Variables Enhance the Predictive Performance of Myocardial Injury in Patients with High Cardiovascular Risk After Thoracic Surgery When Added to Baseline Prediction Model

Purpose

Myocardial injury after non-cardiac surgery is closely related to major adverse cardiac and cerebrovascular event and is difficult to identify. This study aims to investigate how to predict the myocardial injury of thoracic surgery and whether intraoperative variables contribute to the prediction of myocardial injury.

Methods

The prospective study included adult patients with high cardiovascular risk who underwent elective thoracic surgery from May 2022 to October 2022. Multivariate logistic regression was used to establish a model with baseline variables and a model with baseline and intraoperative variables. We compare the predictive performance of two models for postoperative myocardial injury.

Results

In general, 31.5% (94 of 298) occurred myocardial injury. Age ≥65 years old, obesity, smoking, preoperative hsTnT, and one-lung ventilation time were independent predictors of myocardial injury. Compared with baseline model, the intraoperative variables improved model fit, modestly improved the reclassification (continuous net reclassification improvement 0.409, 95% CI, 0.169 to 0.648, P<0.001, improved integrated discrimination 0.036, 95% CI, 0.011 to 0.062, P<0.01) of myocardial injury cases, and achieved higher net benefit in decision curve analysis.

Conclusion

The risk stratification and anesthesia management of high-risk patients are essential. The addition of intraoperative variables to the baseline predictive model improved the performance of the overall model of myocardial injury and helped anesthesiologists screen out the patients at the greatest risk for myocardial injury and adjust anesthesia strategies.

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.

Long-term major adverse cardiovascular events following myocardial injury after non-cardiac surgery: meta-analysis

BACKGROUND

Myocardial injury after non-cardiac surgery is diagnosed following asymptomatic troponin elevation in the perioperative interval. Myocardial injury after non-cardiac surgery is associated with high mortality rates and significant rates of major adverse cardiac events within the first 30 days following surgery. However, less is known regarding its impact on mortality and morbidity beyond this time. This systematic review and meta-analysis aimed to establish the rates of long-term morbidity and mortality associated with myocardial injury after non-cardiac surgery.

METHODS

MEDLINE, Embase and Cochrane CENTRAL were searched, and abstracts screened by two reviewers. Observational studies and control arms of trials, reporting mortality and cardiovascular outcomes beyond 30 days in adult patients diagnosed with myocardial injury after non-cardiac surgery, were included. Risk of bias was assessed using the Quality in Prognostic Studies tool. A random-effects model was used for the meta-analysis of outcome subgroups.

RESULTS

Searches identified 40 studies. The meta-analysis of 37 cohort studies found a rate of major adverse cardiac events-associated myocardial injury after non-cardiac surgery of 21 per cent and mortality following myocardial injury after non-cardiac surgery was 25 per cent at 1-year follow-up. A non-linear increase in mortality rate was observed up to 1 year after surgery. Major adverse cardiac event rates were also lower in elective surgery compared with a subgroup including emergency cases. The analysis demonstrated a wide variety of accepted myocardial injury after non-cardiac surgery and major adverse cardiac events diagnostic criteria within the included studies.

CONCLUSION

A diagnosis of myocardial injury after non-cardiac surgery is associated with high rates of poor cardiovascular outcomes up to 1 year after surgery. Work is needed to standardize diagnostic criteria and reporting of myocardial injury after non-cardiac surgery-related outcomes.

REGISTRATION

This review was prospectively registered with PROSPERO in October 2021 (CRD42021283995).

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.

The use of remimazolam versus propofol for induction and maintenance of general anesthesia: A systematic review and meta-analysis

Background: The primary objective of this study was to compare the risk of hypotension, as well as the induction and recovery characteristics between remimazolam and propofol in patients receiving surgery under general anesthesia. Methods: The Embase, Medline, Google scholar, and the Cochrane Library databases were searched from inception to March 2022 for randomized controlled trials The primary outcome was the risk of post-induction hypotension between the two agents, while the secondary outcomes included anesthetic depth, induction efficacy, time to loss of consciousness (LOC), hemodynamic profiles, time to eye opening, extubation time as well as the incidence of injection pain and postoperative nausea/vomiting (PONV). Results: Meta-analysis of eight studies published from 2020 to 2022 involving 738 patients revealed a significantly lower risk of post-induction hypotension with the use of remimazolam compared to that with propofol [risk ratio (RR) = 0.57, 95% confidence interval (CI): 0.43 to 0.75, p < 0.0001, I2 = 12%, five studies, 564 patients]. After anesthetic induction, the anesthetic depth measured by bispectral index (BIS) was lighter in the remimazolam group than that in the propofol group (MD = 9.26, 95% confidence interval: 3.06 to 15.47, p = 0.003, I2 = 94%, five studies, 490 patients). The time to loss of consciousness was also longer in the former compared to the latter (MD = 15.49 s, 95%CI: 6.53 to 24.46, p = 0.0007, I2 = 61%, three studies, 331 patients). However, the use of remimazolam correlated with a lower risk of injection pain (RR = 0.03, 95%CI: 0.01 to 0.16, p < 0.0001, I2 = 0%, three studies, 407 patients) despite comparable efficacy of anesthetic induction (RR = 0.98, 95%CI: 0.9 to 1.06, p = 0.57, I2 = 76%, two studies, 319 patients). Our results demonstrated no difference in time to eye opening, extubation time, and risk of PONV between the two groups. Conclusion: Remimazolam was associated with a lower risk of post-induction hypotension after anesthetic induction compared with propofol with similar recovery characteristics. Further studies are required to support our findings. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/; Identifier: CRD42022320658.

Hypobaric Unilateral Spinal Anesthesia Versus General Anesthesia for Hip Fracture Surgery in the Elderly: A Randomized Controlled Trial

BACKGROUND

Hypotension during surgery is frequent in the elderly population and is associated with acute kidney and myocardial injury, which are, themselves, associated with increased 30-day mortality. The present study compared the hemodynamic effects of hypobaric unilateral spinal anesthesia (HUSA) to general anesthesia (GA) in patients ≥70 years of age undergoing hip fracture surgery.

METHODS

We conducted a single-center, prospective, randomized study. In the HUSA group, patients were positioned with the operated hip above, and the hypobaric anesthetic solution was composed of 9 mg ropivacaine, 5 µg sufentanil, and 1 mL of sterile water. Anesthesia was adjusted for the GA group. Mean arterial pressure (MAP) was measured with a noninvasive blood pressure upper arm cuff every 3 minutes. Hypotension was treated with a bolus of ephedrine and then a continuous intravenous of norepinephrine to obtain a MAP ≥65 mm Hg. Primary outcome was the occurrence of severe hypotension, defined as a MAP <65 mm Hg for >12 consecutive minutes.

RESULTS

A total of 154 patients were included. Severe hypotension was more frequent in the GA group compared to the HUSA group (odds ratio, 5.6; 95% confidence interval, 2.7-11.7; P < .001). There was no significant difference regarding the short-term outcomes between the HUSA and GA groups: acute kidney injury (respectively, 5.1% vs 11.3%; P = .22), myocardial injury (18.0% vs 14.0%; P = .63), and 30-day mortality (2.4% vs 4.7%; P = .65).

CONCLUSIONS

HUSA leads to fewer episodes of severe intraoperative hypotension compared to GA in an elderly population undergoing hip fracture surgery.

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.

Intraoperative Hypotension and Myocardial Injury After Noncardiac Surgery in Adults With or Without Chronic Hypertension: A Retrospective Cohort Analysis

BACKGROUND

The risk of myocardial injury progressively increases at intraoperative mean arterial pressures (MAPs) ≤65 mm Hg. Higher pressures might be required in chronically hypertensive patients. We aimed to test the hypothesis that the harm threshold is higher in patients with chronic hypertension than in normotensive patients.

METHODS

We conducted a single-center retrospective cohort analysis of adults >45 years old who had noncardiac surgery between 2010 and 2018 and scheduled, rather than symptom-driven, postoperative troponin measurements. The MAP thresholds under which risk started to increase were compared between patients with chronic hypertension (baseline MAP ≥110 mm Hg) and normotensive patients (baseline MAP <110 mm Hg). The primary outcome was a composite of in-hospital mortality and myocardial injury within 30 days, defined by any postoperative 4th-generation troponin T measurement ≥0.03 ng/mL apparently due to cardiac ischemia. Multivariable logistic regression and moving average smoothing methods were used to evaluate confounder-adjusted associations between the composite outcome and the lowest intraoperative MAP sustained for either 5 or 10 cumulative minutes, and whether the relationship depended on baseline pressure (normotensive versus hypertensive).

RESULTS

Among 4576 eligible surgeries, 2066 were assigned to the normotensive group with mean (standard deviation [SD]) baseline MAP of 100 (7) mm Hg, and 2510 were assigned to the hypertensive group with mean baseline MAP of 122 (10) mm Hg. The overall incidence of the composite outcome was 5.6% in normotensive and 6.0% in hypertensive patients ( P = .55). The relationship between intraoperative hypotension and the composite outcome was not found to depend on baseline MAP in a multivariable mixed effects logistic regression model. Furthermore, no statistical change points were found for either baseline MAP group.

CONCLUSIONS

Baseline blood pressure of the hypertensive patients was only moderately increased on average, and the event rate was low. Nonetheless, we were not able to demonstrate a difference in the harm threshold between normotensive and chronically hypertensive patients. Our results do not support the theory that hypertensive patients should be kept at higher intraoperative pressures than normotensive patients.

Provisional Decision-Making for Perioperative Blood Pressure Management: A Narrative Review

Blood pressure (BP) is a basic determinant for organ blood flow supply. Insufficient blood supply will cause tissue hypoxia, provoke cellular oxidative stress, and to some extent lead to organ injury. Perioperative BP is labile and dynamic, and intraoperative hypotension is common. It is unclear whether there is a causal relationship between intraoperative hypotension and organ injury. However, hypotension surely compromises perfusion and causes harm to some extent. Because the harm threshold remains unknown, various guidelines for intraoperative BP management have been proposed. With the pending definitions from robust randomized trials, it is reasonable to consider observational analyses suggesting that mean arterial pressures below 65 mmHg sustained for more than 15 minutes are associated with myocardial and renal injury. Advances in machine learning and artificial intelligence may facilitate the management of hemodynamics globally, including fluid administration, rather than BP alone. The previous mounting studies concentrated on associations between BP targets and adverse complications, whereas few studies were concerned about how to treat and multiple factors for decision-making. Hence, in this narrative review, we discussed the way of BP measurement and current knowledge about baseline BP extracting for surgical patients, highlighted the decision-making process for BP management with a view to providing pragmatic guidance for BP treatment in the clinical settings, and evaluated the merits of an automated blood control system in predicting hypotension.

Prediction of intraoperative hypotension from the linear extrapolation of mean arterial pressure

BACKGROUND

Hypotension prediction index (HPI) software is a proprietary machine learning-based algorithm used to predict intraoperative hypotension (IOH). HPI has shown superiority in predicting IOH when compared to the predictive value of changes in mean arterial pressure (ΔMAP) alone. However, the predictive value of ΔMAP alone, with no reference to the absolute level of MAP, is counterintuitive and poor at predicting IOH. A simple linear extrapolation of mean arterial pressure (LepMAP) is closer to the clinical approach.

OBJECTIVES

Our primary objective was to investigate whether LepMAP better predicts IOH than ΔMAP alone.

DESIGN

Retrospective diagnostic accuracy study.

SETTING

Two tertiary University Hospitals between May 2019 and December 2019.

PATIENTS

A total of 83 adult patients undergoing high risk non-cardiac surgery.

DATA SOURCES

Arterial pressure data were automatically extracted from the anaesthesia data collection software (one value per minute). IOH was defined as MAP < 65 mmHg.

ANALYSIS

Correlations for repeated measurements and the area under the curve (AUC) from receiver operating characteristics (ROC) were determined for the ability of LepMAP and ΔMAP to predict IOH at 1, 2 and 5 min before its occurrence (A-analysis, using the whole dataset). Data were also analysed after exclusion of MAP values between 65 and 75 mmHg (B-analysis).

RESULTS

A total of 24 318 segments of ten minutes duration were analysed. In the A-analysis, ROC AUCs to predict IOH at 1, 2 and 5 min before its occurrence by LepMAP were 0.87 (95% confidence interval, CI, 0.86 to 0.88), 0.81 (95% CI, 0.79 to 0.83) and 0.69 (95% CI, 0.66 to 0.71) and for ΔMAP alone 0.59 (95% CI, 0.57 to 0.62), 0.61 (95% CI, 0.59 to 0.64), 0.57 (95% CI, 0.54 to 0.69), respectively. In the B analysis for LepMAP these were 0.97 (95% CI, 0.9 to 0.98), 0.93 (95% CI, 0.92 to 0.95) and 0.86 (95% CI, 0.84 to 0.88), respectively, and for ΔMAP alone 0.59 (95% CI, 0.53 to 0.58), 0.56 (95% CI, 0.54 to 0.59), 0.54 (95% CI, 0.51 to 0.57), respectively. LepMAP ROC AUCs were significantly higher than ΔMAP ROC AUCs in all cases.

CONCLUSIONS

LepMAP provides reliable real-time and continuous prediction of IOH 1 and 2 min before its occurrence. LepMAP offers better discrimination than ΔMAP at 1, 2 and 5 min before its occurrence. Future studies evaluating machine learning algorithms to predict IOH should be compared with LepMAP rather than ΔMAP.

Perioperative Myocardial Injury/Infarction After Non-cardiac Surgery in Elderly Patients

At present, we have entered an aging society. Many diseases suffered by the elderly, such as malignant tumors, cardiovascular diseases, fractures, surgical emergencies and so on, need surgical intervention. With the improvement of Geriatrics, surgical minimally invasive technology and anesthesia level, more and more elderly patients can safely undergo surgery. Elderly surgical patients are often complicated with a variety of chronic diseases, and the risk of postoperative myocardial injury/infarction (PMI) is high. PMI is considered to be the increase of cardiac troponin caused by perioperative ischemia, which mostly occurs during operation or within 30 days after operation, which can increase the risk of short-term and long-term death. Therefore, it is suggested to screen troponin in elderly patients during perioperative period, timely identify patients with postoperative myocardial injury and give appropriate treatment, so as to improve the prognosis. The pathophysiological mechanism of PMI is mainly due to the increase of myocardial oxygen consumption and / the decrease of myocardial oxygen supply. Preoperative and postoperative risk factors of myocardial injury can be induced by mismatch of preoperative and postoperative oxygen supply. The treatment strategy should first control the risk factors and use the drugs recommended in the guidelines for treatment. Application of cardiovascular drugs, such as antiplatelet β- Receptor blockers, statins and angiotensin converting enzyme inhibitors can effectively improve postoperative myocardial ischemia. However, the risk of perioperative bleeding should be fully considered before using antiplatelet and anticoagulant drugs. This review is intended to describe the epidemiology, diagnosis, pathophysiology, risk factors, prognosis and treatment of postoperative myocardial infarction /injury.

The burden of perioperative hypertension/hypotension: A systematic review

Study objective

Our goal is to review the outcomes of acute hypertensive/hypotensive episodes from articles published in the past 10 years that assessed the short- and long-term impact of acute hypertensive/hypotensive episodes in the perioperative setting.

Methods

We conducted a systematic peer review based upon PROSPERO and Cochrane Handbook protocols. The following study characteristics were collected: study type, author, year, population, sample size, their definition of acute hypertension, hypotension or other measures, and outcomes (probabilities, odds ratio, hazard ratio, and relative risk) and the p-values; and they were classified according to the type of surgery (cardiac and non-cardiac).

Results

A total of 3,680 articles were identified, and 66 articles fulfilled the criteria for data extraction. For the perioperative setting, the number of articles varies by outcome: 20 mortality, 16 renal outcomes, 6 stroke, 7 delirium and 34 other outcomes. Hypotension was reported to be associated with mortality (OR 1.02–20.826) as well as changes from the patient’s baseline blood pressure (BP) (OR 1.02–1.36); hypotension also had a role in the development of acute kidney injury (AKI) (OR 1.03–14.11). Postsurgical delirium was found in relation with BP lability (OR 1.018–1.038) and intra- and postsurgical hypotension (OR 1.05–1.22), and hypertension (OR 1.44–2.34). Increased OR (37.67) of intracranial hemorrhage was associated to postsurgical systolic BP >130 mmHg. There was a wide range of additional diverse outcomes related to hypo-, hypertension and BP lability.

Conclusions

The perioperative management of BP influences short- and long-term effects of surgical procedures in cardiac and non-cardiac interventions; these findings support the burden of BP fluctuations in this setting.

OUP accepted manuscript

OBJECTIVE

We developed a comprehensive, medication-related clinical decision support (CDS) software prototype for use in the operating room. The purpose of this study was to compare the usability of the CDS software to the current standard electronic health record (EHR) medication administration and documentation workflow.

MATERIALS AND METHODS

The primary outcome was the time taken to complete all simulation tasks. Secondary outcomes were the total number of mouse clicks and the total distance traveled on the screen in pixels. Forty participants were randomized and assigned to complete 7 simulation tasks in 1 of 2 groups: (1) the CDS group (n = 20), who completed tasks using the CDS and (2) the Control group (n = 20), who completed tasks using the standard medication workflow with retrospective manual documentation in our anesthesia information management system. Blinding was not possible. We video- and audio-recorded the participants to capture quantitative data (time on task, mouse clicks, and pixels traveled on the screen) and qualitative data (think-aloud verbalization).

RESULTS

The CDS group mean total task time (402.2 ± 85.9 s) was less than the Control group (509.8 ± 103.6 s), with a mean difference of 107.6 s (95% confidence interval [CI], 60.5-179.5 s, P < .001). The CDS group used fewer mouse clicks (26.4 ± 4.5 clicks) than the Control group (56.0 ± 15.0 clicks) with a mean difference of 29.6 clicks (95% CI, 23.2-37.6, P < .001). The CDS group had fewer pixels traveled on the computer monitor (59.5 ± 20.0 thousand pixels) than the Control group (109.3 ± 40.8 thousand pixels) with a mean difference of 49.8 thousand pixels (95% CI, 33.0-73.7, P < .001).

CONCLUSIONS

The perioperative medication-related CDS software prototype substantially outperformed standard EHR workflow by decreasing task time and improving efficiency and quality of care in a simulation setting.

Preoperative ultrasonographic evaluation of subclavian vein and inferior vena cava for predicting hypotension associated with induction of general anesthesia

Introduction:

Induction of general anesthesia is often associated with hypotension and is a common scenario faced by anesthesiologists. Intraoperative hypotension can have detrimental effects and cause various adverse effects leading to an extended hospital stay. Patients' preinduction volume status can have an effect on postinduction blood pressure. Ultrasonography is a useful tool for measuring intravascular volume status. We studied the ability of ultrasonographic measurement of subclavian vein (SCV) and inferior vena cava (IVC) diameter, collapsibility index (CI) to predict hypotension after induction of general anesthesia.

Materials and Methods:

We included 120 patients in our study. SCV measurements during spontaneous and deep inspiration and IVC measurements were taken before induction and postinduction blood pressure was monitored. Patients with mean arterial blood pressure <60 mmHg or with a 30% decrease from baseline were considered to be having hypotension.

Results:

The CI of IVC with a cutoff 37% showed sensitivity of 94% and specificity of 84% which was statistically significant. The CI of 36% of SCV during deep breathing was found to have high sensitivity and specificity of 90% and 87%.

Conclusion:

Our study in spontaneously breathing preoperative patients shows that SCV CI in deep breathing and IVC CI is very sensitive and reliable in predicting postinduction hypotension. Bedside ultrasound measurements can be easily done to obtain valuable information to recognize patients who could be at risk from postinduction hypotension.

A Monte Carlo Simulation to Estimate the Additional Cost Associated With Adverse Medication Events Leading to Intraoperative Hypotension and/or Hypertension in the United States

OBJECTIVES

Intraoperative hypertension and hypotension are common and often related to adverse medication events (AMEs). The study objective is to estimate the annual additional fully allocated costs to the U.S. healthcare system related to AMEs associated with clinically significant intraoperative hypertension and hypotension.

METHODS

Using anesthesia-trained observers in randomly selected operating rooms, we estimated the rates of clinically significant intraoperative hypotension and hypertension. We conducted systematic literature reviews to estimate incidence and additional costs of acute kidney injury (AKI), acute myocardial injury, and stroke after intraoperative hypotension and hypertension. We used Monte Carlo simulation to estimate annual costs to the U.S. healthcare system.

RESULTS

Intraoperative hypotension (mean arterial pressure <55 mm Hg for >6 minutes) occurred in 11 of 277 operations (3.97%), hypotension (>30% drop from baseline mean arterial pressure in patients with coronary artery disease) in 9 operations (3.25%) and hypertension in 14 operations (5.05%). After hypotension, incremental incidence of AKI was 1.46% (additional cost $17,289/case), acute myocardial injury was 0.75% ($21,340/case), and stroke was 0.05% ($19,903/case). After hypertension, incremental stroke incidence was 4.76% ($28,320/case). Annually in the United States, we estimated 11,513 cases of AKI, 5914 of acute myocardial injury, 345 of stroke after intraoperative hypotension, and 47,774 cases of stroke after intraoperative hypertension, costing the U.S. $1.7 billion (90% confidence interval, $1.4-$2.0 billion), of which $923 million (90% confidence interval, $763-$1101 million) is preventable.

CONCLUSIONS

Adverse medication events related to blood pressure are frequent, costly, and can cause considerable patient harm. Cost estimates for these events may provide a means of prioritizing safety improvements to reduce cost of care and improve patient outcomes.

Early intraoperative hypotension and its associated factors among surgical patients undergoing surgery under general anesthesia: An observational study

Background

Early intraoperative hypotension (eIOH) is a common complication of general anesthesia and is significantly associated with postoperative morbidity and mortality. The incidence of eIOH was high, especially in resource-limited settings. Identifying the factors associated with the occurrence of eIOH might allow avoidance and planning of a timely treatment of it.

Objective

To assess the incidence of early intraoperative hypotension and its associated factors among surgical patients undergoing Surgical procedures under general anesthesia at XX Comprehensive Specialized Hospital, North-central Ethiopia, 2021.

Methods

A total of 424 surgical patients under general anesthesia were included in this prospective observational study. The data were collected by a structured questionnaire. Variables with p-values of less than 0.2 in the bivariable logistic regression were fitted to multivariable logistic regression. Data was presented in odds ratios with a 95% confidence interval. Descriptive statistics were used to summarize data.

Results

The incidence of early intra-operative hypotension (eIOH) was 21.2%. In this study older age (age≥ 60 years) (AOR: 2.063 (95% CI;1.194, 3.563)), ASA physical status (AOR: (II2.259 (95% CI;1.229, 4.153)), III(AOR: 2.810 (95% CI;1.319, 5.986)), a BMI of 25–29.9 kg/m2 (AOR: 2.098 (1.128, 3.901), a BMI of ≥30 kg/m2 (AOR: 3.090 (95% CI;1.324, 7.210)), emergency surgical procedures (AOR: 2.215 (95% CI;1.287, 3.810)), the estimated blood loss greater than 500 ml (AOR: 2.510 (95% CI;1.478, 4.261)) were found to be independent factors of eIOH.

Conclusion

This study revealed that the incidence of eIOH was high (21.2%). Older age, ASA II and III, BMI ≥25, emergency surgical procedures, and a significant amount of blood loss (EBL ≥500 ml) were the main predictors of an increased occurrence of eIOH.

•

Early intraoperative hypotension is associated with postoperative morbidity and mortality.

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Emergency surgical procedures, and a significant amount of blood loss are the main predictors of an increased occurrence of eIOH.

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Thyroidectomy has a relatively short duration and less amount of estimated blood loss when compared to major surgical procedures.

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The occurrence of eIOH after general anesthesia for general surgery is a common problem.

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Arterial hypotension in patients undergoing surgery under general anesthesia usually described by the very general term intraoperative hypotension.

Heterogeneous impact of hypotension on organ perfusion and outcomes: a narrative review

Arterial blood pressure is the driving force for organ perfusion. Although hypotension is common in acute care, there is a lack of accepted criteria for its definition. Most practitioners regard hypotension as undesirable even in situations that pose no immediate threat to life, but hypotension does not always lead to unfavourable outcomes based on experience and evidence. Thus efforts are needed to better understand the causes, consequences, and treatments of hypotension. This narrative review focuses on the heterogeneous underlying pathophysiological bases of hypotension and their impact on organ perfusion and patient outcomes. We propose the iso-pressure curve with hypotension and hypertension zones as a way to visualize changes in blood pressure. We also propose a haemodynamic pyramid and a pressure-output-resistance triangle to facilitate understanding of why hypotension can have different pathophysiological mechanisms and end-organ effects. We emphasise that hypotension does not always lead to organ hypoperfusion; to the contrary, hypotension may preserve or even increase organ perfusion depending on the relative changes in perfusion pressure and regional vascular resistance and the status of blood pressure autoregulation. Evidence from RCTs does not support the notion that a higher arterial blood pressure target always leads to improved outcomes. Management of blood pressure is not about maintaining a prespecified value, but rather involves ensuring organ perfusion without undue stress on the cardiovascular system.

Intraoperative Hypotension Is Associated With Adverse Clinical Outcomes After Noncardiac Surgery

Intraoperative hypotension (IOH) occurs frequently during surgery and may be associated with organ ischemia; however, few multicenter studies report data regarding its associations with adverse postoperative outcomes across varying hemodynamic thresholds. Additionally, no study has evaluated the association between IOH exposure and adverse outcomes among patients by various age groups.

Intraoperative Hypotension and Myocardial Infarction Development Among High-Risk Patients Undergoing Noncardiac Surgery: A Nested Case-Control Study

BACKGROUND

Hemodynamic instability during anesthesia and surgery is common and associated with cardiac morbidity and mortality. Information is needed regarding optimal blood pressure (BP) threshold in the perioperative period. Therefore, the effect of intraoperative hypotension (IOH) on risk of perioperative myocardial infarction (MI) was explored.

METHODS

A nested case-control study with patients developing MI <30 days postsurgery matched with non-MI patients, sampled from a large surgery cohort. Study participants were adults undergoing noncardiac surgery at 3 university hospitals in Sweden, 2007-2014. Matching criteria were age, sex, American Society of Anesthesiologists (ASA) physical status, cardiovascular disease, hospital, year-, type-, and extent of surgery. Medical records were reviewed to validate MI diagnoses and retrieve information on comorbid history, baseline BP, laboratory and intraoperative data. Main exposure was IOH, defined as a decrease in systolic blood pressure (SBP), in mm Hg, from preoperative individual resting baseline lasting at least 5 minutes. Outcomes were acute MI, fulfilling the universal criteria, subclassified as type 1 and 2, occurring within 30 days and mortality beyond 30 days among case and control patients. Conditional logistic regression assessed the association between IOH, decrease in SBP from individual baseline, and perioperative MI. Mortality rates were estimated using Cox proportional hazards. Relative risk estimates are reported as are the corresponding absolute risks derived from the well-characterized source population.

RESULTS

A total of 326 cases met the inclusion criteria and were successfully matched with 326 controls. The distribution of MI type was 59 (18%) type 1 and 267 (82%) type 2. Median time to MI diagnosis was 2 days; 75% were detected within a week of surgery. Multivariable analysis acknowledged IOH as an independent risk factor of perioperative MI. IOH, with reduction of 41-50 mm Hg, from individual baseline SBP, was associated with a more than tripled increased odds, odds ratio (OR) = 3.42 (95% confidence interval [CI], 1.13-10.3), and a hypotensive event >50 mm Hg with considerably increased odds in respect to MI risk, OR = 22.6, (95% CI, 7.69-66.2). In patients with a very high-risk burden, the absolute risk of an MI diagnosis increased from 3.6 to 68 per 1000 surgeries.

CONCLUSIONS

In patients undergoing noncardiac surgery, IOH is a possible contributor to clinically significant perioperative MI. The high absolute MI risk associated with IOH, among a growing population of patients with a high-risk burden, suggests that increased vigilance of BP control in these patients may be beneficial.

Predicting peri-operative troponin elevation by advanced electrocardiography

BACKGROUND

Peri-operative mortality remains a global problem and an improved pre-operative risk assessment identifying those at highest risk for peri-operative myocardial injury might improve postsurgical outcomes.

AIMS

To determine whether pre-operative measures of advanced electrocardiography (A-ECG) could predict elevated serum troponin T (TnT) in patients undergoing elective, major non-cardiac surgery.

MATERIAL AND METHODS

This observational cohort study included 257 surgical patients who underwent elective major non-cardiac surgery between the years 2012-2013 and 2015-2016 at Karolinska University Hospital. All selected patients were ≥ 18 years of age [median age 70 (63-75) years], had a pre-operative digital 12‑lead ECG < 6 months prior to the procedure and a postoperative high-sensitivity cardiac TnT (hs-cTnT) sample. A-ECG confounders including atrial fibrillation or flutter, abundant premature atrial or ventricular contractions, bundle branch blocks, QRS duration >110 ms, heart rate > 100 beats/min and paced rhythms were excluded. Previously validated A-ECG diagnostic scores that detect cardiovascular pathologies were calculated and compared in patients with and without peri-operative myocardial injury, defined as hs-cTnT >14 ng l^-1.

RESULTS

Pre-operative left ventricular systolic dysfunction by A-ECG was more probable in patients with than without peri-operative myocardial injury (p = 0.03).

CONCLUSIONS

While a pre-operative A-ECG score for LVSD was able to differentiate between patients with versus without elevated peri-operative TnT levels, it did not add any further utility to standard clinical parameters for predicting troponin-related events in the studied population.

Epidural Anesthesia-Analgesia and Recurrence-free Survival after Lung Cancer Surgery: A Randomized Trial

BACKGROUND

Regional anesthesia and analgesia reduce the stress response to surgery and decrease the need for volatile anesthesia and opioids, thereby preserving cancer-specific immune defenses. This study therefore tested the primary hypothesis that combining epidural anesthesia-analgesia with general anesthesia improves recurrence-free survival after lung cancer surgery.

METHODS

Adults scheduled for video-assisted thoracoscopic lung cancer resections were randomized 1:1 to general anesthesia and intravenous opioid analgesia or combined epidural-general anesthesia and epidural analgesia. The primary outcome was recurrence-free survival (time from surgery to the earliest date of recurrence/metastasis or all-cause death). Secondary outcomes included overall survival (time from surgery to all-cause death) and cancer-specific survival (time from surgery to cancer-specific death). Long-term outcome assessors were blinded to treatment.

RESULTS

Between May 2015 and November 2017, 400 patients were enrolled and randomized to general anesthesia alone (n = 200) or combined epidural-general anesthesia (n = 200). All were included in the analysis. The median follow-up duration was 32 months (interquartile range, 24 to 48). Recurrence-free survival was similar in each group, with 54 events (27%) with general anesthesia alone versus 48 events (24%) with combined epidural-general anesthesia (adjusted hazard ratio, 0.90; 95% CI, 0.60 to 1.35; P = 0.608). Overall survival was also similar with 25 events (13%) versus 31 (16%; adjusted hazard ratio, 1.12; 95% CI, 0.64 to 1.96; P = 0.697). There was also no significant difference in cancer-specific survival with 24 events (12%) versus 29 (15%; adjusted hazard ratio, 1.08; 95% CI, 0.61 to 1.91; P = 0.802). Patients assigned to combined epidural-general had more intraoperative hypotension: 94 patients (47%) versus 121 (61%; relative risk, 1.29; 95% CI, 1.07 to 1.55; P = 0.007).

CONCLUSIONS

Epidural anesthesia-analgesia for major lung cancer surgery did not improve recurrence-free, overall, or cancer-specific survival compared with general anesthesia alone, although the CI included both substantial benefit and harm.

EDITOR’S PERSPECTIVE

Remimazolam Anesthesia for MitraClip Implantation in a Patient with Advanced Heart Failure

Remimazolam, a novel and ultrashort-acting benzodiazepine, has been available for general anesthesia in Japan. The administration of remimazolam does not induce injection pain, has been reported to have less cardiovascular depressant effects during general anesthesia, and flumazenil can antagonize the effects of remimazolam. However, in clinical trials, no patient who is complicated with severe heart failure or undergoes cardiac surgery was included. We present anesthetic management with remimazolam for MitraClip^® implantation in a patient with severe mitral regurgitation and advanced heart failure. Remimazolam was administered both in anesthetic induction and maintenance with less cardiovascular depressant effects. After surgical procedures were completed, the patient smoothly recovered from anesthesia and the tracheal was extubated just after administration of flumazenil. Remimazolam may be able to achieve appropriate anesthetic management in patients complicated with severe cardiovascular diseases.

Prediction of Death After Noncardiac Surgery: Potential Advantage of Using High-Sensitivity Troponin T as a Continuous Variable

Background

Increased high‐sensitivity cardiac troponin T (hs‐cTnT) above the upper reference limit (URL) after noncardiac surgery identifies patients at risk for mortality. Prior studies have not analyzed hs‐cTnT as a continuous variable or probed age‐ and sex‐specific URLs. This study compared the prediction of 30‐day mortality using continuous postoperative hs‐cTnT levels to the use of the overall URL and age‐ and sex‐specific URLs.

Methods and Results

Patients (876) >40 years of age who underwent noncardiac surgery were included. Hs‐cTnT was measured on postoperative day 1. Cox proportional hazards models were used to compare associations between 30‐day mortality and using hs‐cTnT as a continuous variable, or above the overall or age‐ and sex‐specific URLs. Comparisons were performed by the area under the receiver operating characteristic curve analysis. Mortality was 4.2%. For each 1 ng/L increase in postoperative hs‐cTnT, there was a 0.3% increase in mortality (P<0.001). Patients with postoperative hs‐cTnT >14 ng/L were 37% of the cohort, while those above age‐ and sex‐specific URLs were 25.3%. Both manifested higher mortality (hazard ratio [HR], 3.19; 95% CI, 1.20–8.49; P=0.020) and (HR, 2.76; P=0.009) than those with normal levels. The area under receiver operating characteristic curve was 0.89 using hs‐cTnT as a continuous variable, 0.87 for age‐ and sex‐specific URLs, and 0.86 for the overall URL.

Conclusions

Hs‐cTnT as a continuous variable was independently associated with 30‐day mortality and had the highest accuracy. Hs‐cTnT elevations using overall and/or age‐ and sex‐specific URLs were also associated with higher mortality.

Association of intraoperative hypotension with postoperative morbidity and mortality: systematic review and meta-analysis

Background

Intraoperative hypotension, with varying definitions in literature, may be associated with postoperative complications. The aim of this meta-analysis was to assess the association of intraoperative hypotension with postoperative morbidity and mortality.

Methods

MEDLINE, Embase and Cochrane databases were searched for studies published between January 1990 and August 2018. The primary endpoints were postoperative overall morbidity and mortality. Secondary endpoints were postoperative cardiac outcomes, acute kidney injury, stroke, delirium, surgical outcomes and combined outcomes. Subgroup analyses, sensitivity analyses and a meta-regression were performed to test the robustness of the results and to explore heterogeneity.

Results

The search identified 2931 studies, of which 29 were included in the meta-analysis, consisting of 130 862 patients. Intraoperative hypotension was associated with an increased risk of morbidity (odds ratio (OR) 2.08, 95 per cent confidence interval 1.56 to 2.77) and mortality (OR 1.94, 1.32 to 2.84). In the secondary analyses, intraoperative hypotension was associated with cardiac complications (OR 2.44, 1.52 to 3.93) and acute kidney injury (OR 2.69, 1.31 to 5.55). Overall heterogeneity was high, with an I² value of 88 per cent. When hypotension severity, outcome severity and study population variables were added to the meta-regression, heterogeneity was reduced to 50 per cent.

Conclusion

Intraoperative hypotension during non-cardiac surgery is associated with postoperative cardiac and renal morbidity, and mortality. A universally accepted standard definition of hypotension would facilitate further research into this topic.

Development and Evaluation of a Risk-Adjusted Measure of Intraoperative Hypotension in Patients Having Nonemergent, Noncardiac Surgery

Intraoperative hypotension is common and associated with organ injury and death, although randomized data showing a causal relationship remain sparse. A risk-adjusted measure of intraoperative hypotension may therefore contribute to quality improvement efforts.

Common clinical thresholds of intraoperative hypotension and 30-day mortality following surgery: A retrospective cohort study

BACKGROUND

A wide range of thresholds define intraoperative hypotension and can be used to guide intraoperative blood pressure management. Many clinicians use the systolic blood pressure (SBP) <80 mmHg, the mean arterial pressure (MAP) <60 mmHg and the SBP percent drop from baseline (ΔSBP) >20% as alarming limits that should not be exceeded. Whether these common thresholds are valid limits that can inform clinicians on a possible increased risk of post-operative complications, particularly 30-day mortality, is currently unclear.

METHODS

We performed a retrospective registry-based cohort study between January 2015 and July 2016 using departmental hospital databases and the National Death Registry. Uni- and multivariate analyses were performed to assess the association between each of these three thresholds and 30-day post-operative mortality. Six specific markers of hypotension were used.

RESULTS

Of 11 304 patients, 86 (0.76%) died within 30 days following surgery. All intraoperative hypotension markers for SBP < 80 mmHg and MAP < 60 mmHg were significantly associated with 30-day mortality (P < .005). Markers of ΔSBP > 20% were not significant. After adjustment for age, gender, American Society of Anesthesiologists (ASA) score, emergency status and risk related to the type of surgery, both SBP < 80 mmHg and MAP < 60 mmHg (the per cent area under the threshold marker) showed the strongest associations with 30-day mortality, with odds ratios (ORs) of 3.02 (95% confidence interval (CI) 1.81-5.07) and 3.77 (95% CI 2.25-6.31) respectively.

CONCLUSIONS

Commonly accepted thresholds of intraoperative hypotension, such as an SBP of 80 mmHg and an MAP of 60 mmHg, are valid alarming limits that are significantly and independently associated with 30-day mortality.

Arterial Catheters for Early Detection and Treatment of Hypotension During Major Noncardiac Surgery: A Randomized Trial

BACKGROUND

Continuous blood pressure monitoring may facilitate early detection and prompt treatment of hypotension. We tested the hypothesis that area under the curve (AUC) mean arterial pressure (MAP) <65 mm Hg is reduced by continuous invasive arterial pressure monitoring.

METHODS

Adults having noncardiac surgery were randomly assigned to continuous invasive arterial pressure or intermittent oscillometric blood pressure monitoring. Arterial catheter pressures were recorded at 1-minute intervals; oscillometric pressures were typically recorded at 5-minute intervals. We estimated the arterial catheter effect on AUC-MAP <65 mm Hg using a multivariable proportional odds model adjusting for imbalanced baseline variables and duration of surgery. Pressures <65 mm Hg were categorized as 0, 1-17, 18-91, and >91 mm Hg × minutes of AUC-MAP <65 mm Hg (ie, no hypotension and 3 equally sized groups of increasing hypotension).

RESULTS

One hundred fifty-two patients were randomly assigned to arterial catheter use and 154 to oscillometric monitoring. For various clinical reasons, 143 patients received an arterial catheter, while 163 were monitored oscillometrically. There were a median [Q1, Q3] of 246 [187, 308] pressure measurements in patients with arterial catheters versus 55 (46, 75) measurements in patients monitored oscillometrically. In the primary intent-to-treat analysis, catheter-based monitoring increased detection of AUC-MAP <65 mm Hg, with an estimated proportional odds ratio (ie, odds of being in a worse hypotension category) of 1.78 (95% confidence interval [CI], 1.18-2.70; P = .006). The result was robust over an as-treated analysis and for sensitivity analyses with thresholds of 60 and 70 mm Hg.

CONCLUSIONS

Intraoperative blood pressure monitoring with arterial catheters detected nearly twice as much hypotension as oscillometric measurements.

Intraoperative hypotension is associated with increased postoperative complications in patients undergoing surgery for pheochromocytoma-paraganglioma: a retrospective cohort study

BACKGROUND

Dramatic hemodynamic fluctuation occurs frequently during surgery for pheochromocytoma or paraganglioma. However, the criteria of intraoperative hemodynamic instability vary widely, and most of them were defined arbitrarily but not according to patients' prognosis. The objective was to analyze the relationship between different thresholds and durations of intraoperative hyper-/hypotension and the risk of postoperative complications in patients undergoing surgery for pheochromocytoma or paraganglioma.

METHODS

This was a retrospective single-center cohort study performed in a tertiary care hospital from January 1, 2005 to December 31, 2017. Three hundred twenty-seven patients who underwent surgery for pheochromocytoma or paraganglioma, of which the diagnoses were confirmed by postoperative pathologic examination, were enrolled. Those who were less than 18 years, underwent surgery involving non-tumor organs, or had incomplete data were excluded. The primary endpoint was a composite of the occurrence of AKI or other complications during hospital stay after surgery. Multivariate Logistic regression models were used to analyze the association between different thresholds and durations of intraoperative hyper-/hypotension and the development of postoperative complications.

RESULTS

Forty three (13.1%) patients developed complications during hospital stay after surgery. After adjusting for confounding factors, intraoperative hypotension, defined as systolic blood pressure (SBP) of ≤95 mmHg for ≥20 min (OR 3.211; 99% CI 1.081-9.536; P = 0.006), SBP of ≤90 mmHg for ≥20 min (OR 3.680; 98.8% CI 1.107-12.240; P = 0.006), SBP of ≤85 mmHg for ≥10 min (OR 3.975; 98.3% CI 1.321-11.961; P = 0.003), and SBP of ≤80 mmHg for ≥1 min (OR 3.465; 95% CI 1.484-8.093; P = 0.004), were associated with an increased risk of postoperative complications. On the other hand, intraoperative hypertension was not significantly associated with the development of postoperative complications.

CONCLUSIONS

For patients undergoing surgery for pheochromocytoma or paraganglioma, intraoperative hypotension is associated with increased postoperative complications; and the harmful effects are level- and duration-dependent. The effects of intraoperative hypertension need to be studied further.

Troponin I as a mortality marker after lung resection surgery - a prospective cohort study

BACKGROUND

Cardiovascular complications associated with thoracic surgery increase morbidity, mortality, and treatment costs. Elevated cardiac troponin level represents a predictor of complications after non-cardiac surgeries, but its role after thoracic surgeries remains undetermined. The objective of this study was to analyze the relationship between troponin I elevation and morbidity and mortality after one year in patients undergoing lung resection surgery.

METHODS

This prospective cohort study evaluated 151 consecutive patients subjected to elective lung resection procedures using conventional and video-assisted thoracoscopic techniques at a University Hospital in Brazil, from July 2012 to November 2015. Preoperative risk stratification was performed using the scores obtained by the American College of Physicians (ACP) and the Society of Cardiology of the state of São Paulo (EMAPO) scoring systems. Troponin I levels were measured in the immediate postoperative period (POi) and on the first and second postoperative days.

RESULTS

Most patients had a low risk for complications according to the ACP (96.7%) and EMAPO (82.8%) scores. Approximately 49% of the patients exhibited increased troponin I (≥0.16 ng/ml), at least once, and 22 (14.6%) died in one year. Multivariate analysis showed that the elevation of troponin I, on the first postoperative day, correlated with a 12-fold increase in mortality risk within one year (HR 12.02, 95% CI: 1.82-79.5; p = 0.01).

CONCLUSIONS

In patients undergoing lung resection surgery, with a low risk of complications according to the preoperative evaluation scores, an increase in troponin I levels above 0.16 ng/ml in the first postoperative period correlated with an increase in mortality within one year.

Management of veterinary anaesthesia in small animals: A survey of current practice in Quebec

OBJECTIVE

To describe how small animal anaesthesia is performed in French-speaking Eastern Canada, and the variations between practices, in particular based on practice type, veterinarian gender and experience.

DESIGN

Observational study, survey.

SAMPLE

156 respondents.

PROCEDURE

A questionnaire was designed to assess current small animal anaesthesia practices in French-speaking Eastern Canada, mainly in the province of Quebec. The questionnaire was available through SurveyMonkey, and consisted of four parts: demographic information about the veterinarians surveyed, evaluation and management of anaesthetic risk, anaesthesia procedure, monitoring and safety. Gender, year of graduation, and type of practice were tested as potential risk factors. Chi-square exact test was used to study relations between each risk factor, and the effect of the selected risk factor on each response of the survey. For ordinal data, the Cochran-Mantel-Haenszel test was used to maximize power.

RESULTS

Response rate over a period of 3 months was 20.85% (156 respondents). Overall, the way anaesthesia is performed by most respondents does not meet international guidelines, such as patient preparation and evaluation prior to anaesthesia, not using individualised protocols (for 41%), not obtaining intravenous access (12.4% use it for all their anaesthesia in cats, and 30.6% in dogs), lack of patient monitoring at certain intervals for 55% of the responses, and client prompted optional analgesia (for 29% of respondents). Some practices are more compliant than others. Among them, referral centres generally offer better care than general practices.

CONCLUSIONS AND CLINICAL RELEVANCE

The level of care in anaesthesia and analgesia in practices in French-speaking Eastern Canada is concerning, highlighting the need for more sustained continuing education.

Perioperative multidisciplinary implementation enhancing recovery after hip arthroplasty in geriatrics with preoperative chronic hypoxaemia

We investigated risk factors for postoperative serious adverse events (SAEs) in elderly patients with preoperative chronic hypoxaemia undergone total hip arthroplasty (THA) or hemiarthroplasty and performed an implementation to modify and improve clinical outcome. A retrospective medical record review was performed to identify geriatric patients who receiving THA or hemiarthroplasty at a single university teaching hospital, Kunming, Yunnan, China between January 2009 and August 2017. Total of 450 elderly patients were included in the study. Data were collected on baseline characteristics, detailed treatments, and adverse events. Univariate and multivariate logistic regression analysis were used to identify risk factors for SAEs. In multivariate regression analysis, a higher occurrence of general anaesthesia and multiple episodes of hypotension were associated with higher risk of SAEs (general anesthesia: odds ratio [OR] 5.09, 95% confidence interval [CI] 1.96–13.24, P = 0.001; hypotension time: OR 4.29, 95% CI 1.66–11.10, P = 0.003). After the multidisciplinary implementation, the postoperative length of stay was decreased from 15 days to 10 days (P < 0.0001); incidence of SAEs was decreased from 21.1% to 7.0% (P = 0.002), and the all-cause mortality rate within 30 days decreased from 4.6% to 1.0% (P = 0.040). Our observational study demonstrated that an increasing application of general anaesthesia and longer time of hypotension were associated with an increased risk of postoperative SAEs in patients after THA or hemiarthroplasty. Additionally, optimizing stable haemodynamics under higher application of combined-spinal epidural anaesthesia was associated with improved outcome up to 30 days after THA or hemiarthroplasty.

Intraoperative hypotension and its prediction

Intraoperative hypotension (IOH) very commonly accompanies general anaesthesia in patients undergoing major surgical procedures. The development of IOH is unwanted, since it is associated with adverse outcomes such as acute kidney injury and myocardial injury, stroke and mortality. Although the definition of IOH is variable, harm starts to occur below a mean arterial pressure (MAP) threshold of 65 mmHg. The odds of adverse outcome increase for increasing duration and/or magnitude of IOH below this threshold, and even short periods of IOH seem to be associated with adverse outcomes. Therefore, reducing the hypotensive burden by predicting and preventing IOH through proactive appropriate treatment may potentially improve patient outcome. In this review article, we summarise the current state of the prediction of IOH by the use of so-called machine-learning algorithms. Machine-learning algorithms that use high-fidelity data from the arterial pressure waveform, may be used to reveal 'traits' that are unseen by the human eye and are associated with the later development of IOH. These algorithms can use large datasets for 'training', and can subsequently be used by clinicians for haemodynamic monitoring and guiding therapy. A first clinically available application, the hypotension prediction index (HPI), is aimed to predict an impending hypotensive event, and additionally, to guide appropriate treatment by calculated secondary variables to asses preload (dynamic preload variables), contractility (dP/dtmax), and afterload (dynamic arterial elastance, Eadyn). In this narrative review, we summarise the current state of the prediction of hypotension using such novel, automated algorithms and we will highlight HPI and the secondary variables provided to identify the probable origin of the (impending) hypotensive event.

Association of intra-operative hypotension with acute kidney injury, myocardial injury and mortality in non-cardiac surgery: A meta-analysis

BACKGROUND

Intra-operative hypotension might induce poor postoperative outcomes in non-cardiac surgery, and the relationship between the level or duration of Intra-operative hypotension (IOH) and postoperative adverse events is still unclear. In this study, we performed a meta-analysis to determine how IOH could affect acute kidney injury (AKI), myocardial injury and mortality in non-cardiac surgery.

METHODS

We searched PubMed (Medline), Embase, Springer, The Cochrane Library, Ovid and Google Scholar, and retrieved the related clinical trials on intra-operative hypotension and prognosis in non-cardiac surgery.

RESULTS

Fifteen observational studies were included. The meta-analysis showed that in non-cardiac surgery, intra-operative hypotension (mean arterial pressure [MAP]) <60 mm Hg for more than 1 minute was associated with an increased risk of postoperative acute kidney injury(AKI) [1-5 minutes: odds ratio (OR) = 1.13, 95% CI (1.04, 1.23), I²  = 0, P = .003; 5-10 minutes: OR = 1.18, 95% CI (1.07, 1.31), I²  = 0, P = .001; >10 minutes: OR = 1.35, 95% CI (1.1, 1.67), I²  = 52.6%, P = .004] and myocardial injury [1-5 minutes: OR = 1.16, 95% CI (1.01, 1.33), I²  = 30.6%, P = .04; 5-10 minutes: OR = 1.34, 95% CI (1.01, 1.77), I²  = 70.4%, P = .046; >10 minutes: OR = 1.43, 95% CI (1.18, 1.72), I²  = 39.4%, P < .0001]. Intra-operative hypotension (MAP < 60 mm Hg) for 1-5 minutes was not associated with postoperative 30-day mortality [OR = 1.15, 95% CI (0.95, 1.4), I²  = 0, P = .154], but intra-operative hypotension (MAP < 60 mm Hg) for more than 5 min was associated with an increased risk of postoperative 30-day mortality [OR = 1.11, 95% CI (1.06, 1.17), I²  = 51.9%, P < .0001].

CONCLUSION

Intra-operative hypotension was associated with an increased risk of postoperative AKI, myocardial injury and 30-day mortality in non-cardiac surgery. Intra-operative MAP < 60 mm Hg more than 1 minute should be avoided.

Better haemodynamic stability under xenon anaesthesia than under isoflurane anaesthesia during partial nephrectomy - a secondary analysis of a randomised controlled trial

Background

Renal dysfunction following intraoperative arterial hypotension is mainly caused by an insufficient renal blood flow. It is associated with higher mortality and morbidity rates. We hypothesised that the intraoperative haemodynamics are more stable during xenon anaesthesia than during isoflurane anaesthesia in patients undergoing partial nephrectomy.

Methods

We performed a secondary analysis of the haemodynamic variables collected during the randomised, single-blinded, single-centre PaNeX study, which analysed the postoperative renal function in 46 patients who underwent partial nephrectomy. The patients received either xenon or isoflurane anaesthesia with 1:1 allocation ratio. We analysed the duration of the intraoperative systolic blood pressure decrease by > 40% from baseline values and the cumulative duration of a mean arterial blood pressure (MAP) of < 65 mmHg as primary outcomes. The secondary outcomes were related to other blood pressure thresholds, the amount of administered norepinephrine, and the analysis of confounding factors on the haemodynamic stability.

Results

The periods of an MAP of < 65 mmHg were significantly shorter in the xenon group than in the isoflurane group. The medians [interquartile range] were 0 [0–10.0] and 25.0 [10.0–47.5] minutes, for the xenon and isoflurane group, respectively (P = 0.002). However, the cumulative duration of a systolic blood pressure decrease by > 40% did not significantly differ between the groups (P = 0.51). The periods with a systolic blood pressure decrease by 20% from baseline, MAP decrease to values < 60 mmHg, and the need for norepinephrine, as well as the cumulative dose of norepinephrine were significantly shorter and lower, respectively, in the xenon group. The confounding factors, such as demographic data, surgical technique, or anaesthesia data, were similar in the two groups.

Conclusion

The patients undergoing xenon anaesthesia showed a better haemodynamic stability, which might be attributed to the xenon properties. The indirect effect of xenon anaesthesia might be of importance for the preservation of renal function during renal surgery and needs further elaboration.

Trial registration

ClinicalTrials.gov: NCT01839084. Registered 24 April 2013.

Electronic supplementary material

The online version of this article (10.1186/s12871-019-0799-2) contains supplementary material, which is available to authorized users.

Feasibility of closed-loop titration of norepinephrine infusion in patients undergoing moderate- and high-risk surgery

BACKGROUND

Vasopressor agents are used to prevent intraoperative hypotension and ensure adequate perfusion. Vasopressors are usually administered as intermittent boluses or manually adjusted infusions, but this practice requires considerable time and attention. We have developed a closed-loop vasopressor (CLV) controller to correct hypotension more efficiently. Here, we conducted a proof-of-concept study to assess the feasibility and performance of CLV control in surgical patients.

METHODS

Twenty patients scheduled for elective surgical procedures were included in this study. The goal of the CLV system was to maintain MAP within 5 mm Hg of the target MAP by automatically adjusting the rate of a norepinephrine infusion using MAP values recorded continuously from an arterial catheter. The primary outcome was the percentage of time that patients were hypotensive, as defined by a MAP of 5 mm Hg below the chosen target. Secondary outcomes included the total dose of norepinephrine, percentage of time with hypertension (MAP>5 mm Hg of the chosen target), raw percentage "time in target" and Varvel performance criteria.

RESULTS

The 20 subjects (median age: 64 years [52-71]; male (35%)) underwent elective surgery lasting 154 min [124-233]. CLV control maintained MAP within ±5 mm Hg of the target for 91.6% (85.6-93.3) of the intraoperative period. Subjects were hypotensive for 2.6% of the intraoperative period (range, 0-8.4%). Additional performance criteria for the controller included mean absolute performance error of 2.9 (0.8) and mean predictive error of 0.5 (1.0). No subjects experienced major complications.

CONCLUSIONS

In this proof of concept study, CLV control minimised perioperative hypotension in subjects undergoing moderate- or high-risk surgery. Further studies to demonstrate efficacy are warranted.

TRIAL REGISTRY NUMBER

NCT03515161 (ClinicalTrials.gov).

Emergency General Surgery in Older Adults: A Review

Older people are the fastest growing segment of the population and over-represented among people requiring emergency general surgery. Independent of comorbid and procedural factors, perioperative risk increases with increasing age. This effect is amplified with frailty or sarcopenia. Multidisciplinary perioperative care aligned with goals of care is most likely to achieve optimal patient and health system outcomes; however, substantial knowledge gaps exist in emergency general surgery for older people. Anesthesiologists are uniquely positioned to address these knowledge gaps, including optimizing goal-directed intraoperative care, appropriate provision of acute postoperative monitoring, and integration of principles of geriatric medicine in perioperative care.

Causes and prevention of postoperative myocardial injury

Over the past few years non-cardiac surgery has been recognised as a serious circulatory stress test which may trigger cardiovascular events such as myocardial infarction, in particular in patients at high risk. Detection of these postoperative cardiovascular events is difficult as clinical symptoms often go unnoticed. To improve detection, guidelines advise to perform routine postoperative assessment of cardiac troponin. Troponin elevation - or postoperative myocardial injury - can be caused by myocardial infarction. However, also non-coronary causes, such as cardiac arrhythmias, sepsis and pulmonary embolism, may play a role in a considerable number of patients with postoperative myocardial injury. It is crucial to acquire more knowledge about the underlying mechanisms of postoperative myocardial injury because effective prevention and treatment options are lacking. Preoperative administration of beta-blockers, aspirin, statins, clonidine, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, and preoperative revascularisation have all been investigated as preventive options. Of these, only statins should be considered as the initiation or reload of statins may reduce the risk of postoperative myocardial injury. There is also not enough evidence for intraoperative measures such blood pressure optimisation or intensified medical therapy once patients have developed postoperative myocardial injury. Given the impact, better preoperative identification of patients at risk of postoperative myocardial injury, for example using preoperatively measured biomarkers, would be helpful to improve cardiac optimisation.