Association of preoperative beta-blocker use and cardiac complications after major noncardiac surgery: a prospective cohort study

INTRODUCTION

Cardiac complications after major noncardiac surgery are common and associated with high morbidity and mortality. How preoperative use of beta-blockers may impact perioperative cardiac complications remains unclear.

METHODS

In a multicentre prospective cohort study, preoperative beta-blocker use was ascertained in consecutive patients at elevated cardiovascular risk undergoing major noncardiac surgery. Cardiac complications were prospectively monitored and centrally adjudicated by two independent experts. The primary endpoint was perioperative myocardial infarction or injury attributable to a cardiac cause (cardiac PMI) within the first three postoperative days. The secondary endpoints were major adverse cardiac events (MACE), defined as a composite of myocardial infarction, acute heart failure, life-threatening arrhythmia, and cardiovascular death and all-cause death after 365 days. We used inverse probability of treatment weighting to account for differences between patients receiving beta-blockers and those who did not.

RESULTS

A total of 3839/10 272 (37.4%) patients (mean age 74 yr; 44.8% female) received beta-blockers before surgery. Patients on beta-blockers were older, and more likely to be male with established cardiorespiratory and chronic kidney disease. Cardiac PMI occurred in 1077 patients, with a weighted odds ratio of 1.03 (95% confidence interval [CI] 0.94-1.12, P=0.55) for patients on beta-blockers. Within 365 days of surgery, 971/10 272 (9.5%) MACE had occurred, with a weighted hazard ratio of 0.99 (95% CI 0.83-1.18, P=0.90) for patients on beta-blockers.

CONCLUSION

Preoperative use of beta-blockers was not associated with decreased cardiac complications including cardiac perioperative myocardial infarction or injury and major adverse cardiac event. Additionally, preoperative use of beta-blockers was not associated with increased all-cause death within 30 and 365 days.

CLINICAL TRIAL REGISTRATION

NCT02573532.

Is crystalloid co-loading necessary to prevent spinal hypotension during elective cesarean delivery? A randomized double-blind trial

BACKGROUND

Hypotension is common during spinal anesthesia for cesarean delivery. Preventive strategies include fluid loading and phenylephrine. We hypothesized that if prophylactic phenylephrine infusion is used, omission of fluid loading would be non-inferior to fluid co-loading in maintaining cardiac output. We assumed that if there was a difference, the increase in cardiac output would be greater in the no-loading than in the co-loading group.

METHODS

Term pregnant women scheduled for elective cesarean delivery were randomized to receive 1 L crystalloid co-loading or maintenance fluids only. Phenylephrine was titrated to maintain blood pressure. Changes in cardiac output following spinal anesthesia were the primary outcome. The study was powered as a non-inferiority trial, allowing the no-loading arm to have a 50% greater change in cardiac output. Heart rate, dose of phenylephrine, occurrence of nausea and vomiting, Apgar scores and neonatal acid base status were secondary outcomes.

RESULTS

Data from 63 women were analyzed. In contrast to our hypothesis, there was 33% less increase in cardiac output with no loading (ratio 0.67, 95% CI 0.15 to 1.36), and 60% greater reduction of cardiac output with no loading (ratio 1.6, 95% CI 1.0 to 2.7). Total dose of phenylephrine was higher in the no-loading group. There may be a less favorable neonatal acid base status without volume loading.

CONCLUSION

Omission of crystalloid co-loading leads to a decrease in cardiac output which has a potentially unfavorable impact on neonatal acid base status. We conclude that crystalloid co-loading may be useful in the presence of phenylephrine infusion.

How to avoid intraoperative complications of active paragangliomas?

Background

Paragangliomas (PGs) are very rare neuroendocrine tumors that can be found in unusual locations such as the spinal canal. Some PGs may be endocrinologically active, containing neurotransmitters such as noradrenaline, adrenaline, and serotonin. This can lead to unexpected neurotransmitter release during the removal of PGs, leading to a hypertensive crisis.

Case Description

We present two patients who underwent surgical removal of a secretory filum terminale PG.

Conclusion

If laboratory tests are suggestive of a secretory tumor, surgery should include anesthesiologic preparation similar to cases of pheochromocytoma.

Discrepancy in Reporting of Perioperative Complications: A Retrospective Observational Study

OBJECTIVE

To assess the discrepancy between perioperative complications, prospectively recorded during a cohort study versus retrospectively from health records.

BACKGROUND

Perioperative adverse events are relevant for patient outcome, but incomplete reporting is common.

METHODS

Two physicians independently recorded all intraoperative adverse events according to ClassIntra and all postoperative complications according to the Clavien-Dindo classification based on all available health records. These retrospective assessments were compared with the number and severity of those prospectively assessed in the same patients during their inclusion in 1 center of a prospective multicenter cohort study.

RESULTS

Interrater agreement between both physicians for retrospective recording was high [intraclass correlation coefficient: 0.89 (95% CI, 0.86, 0.91) for intraoperative and 0.88 (95% CI, 0.85, 0.90) for postoperative complications]. In 320 patients, the incidence rate was higher retrospectively than prospectively for any intraoperative complication (incidence rate ratio: 1.79; 95% CI, 1.50, 2.13) and for any postoperative complication (incidence rate ratio: 2.21; 95% CI, 1.90, 2.56). In 71 patients, the severity of the most severe intraoperative complication was higher in the retrospective than in the prospective data collection, whereas in 69 the grading was lower. In 106 patients, the severity of the most severe postoperative complication was higher in the retrospective than in the prospective data collection, whereas in 19 the grading was lower.

CONCLUSIONS

There is a noticeable discrepancy in the number and severity of reported perioperative complications between these 2 data collection methods. On the basis of the double-blinded assessment of 2 independent raters, our study renders prospective underreporting more likely than retrospective overreporting.

Guideline adherence to statin therapy and association with short-term and long-term cardiac complications following noncardiac surgery: A cohort study

BACKGROUND

Peri-operative complications are common and associated with high morbidity and mortality. Optimising the use of statins might be of important benefit in peri-operative care and reduce morbidity and mortality.

OBJECTIVE

To evaluate adherence to current guideline recommendations regarding statin therapy and its association with peri-operative and long-term cardiac complications.

DESIGN

Prospective cohort study.

SETTING

Multicentre study with enrolment from October 2014 to February 2018.

PATIENTS

Eight thousand one hundred and sixteen high-risk inpatients undergoing major noncardiac surgery who were eligible for the institutional peri-operative myocardial injury/infarction (PMI) active surveillance and response program.

MAIN OUTCOME MEASURES

Class I indications for statin therapy were derived from the current ESC Clinical Practice Guidelines during the time of enrolment. PMI was prospectively defined as an absolute increase in cTn concentration of the 99th percentile in healthy individuals above the preoperative concentration within the first three postoperative days. Long-term cardiac complications included cardiovascular death and spontaneous myocardial infarction (MI) within 120 days.

RESULTS

The mean age was 73.7 years; 45.2% were women. Four thousand two hundred and twenty-seven of 8116 patients (52.1%) had a class I indication for statin therapy. Of these, 2440 of 4227 patients (57.7%) were on statins preoperatively. Adherence to statins was lower in women than in men (46.9 versus 63.9%, P  < 0.001). PMI due to type 1 myocardial infarction/injury (T1MI; n  = 42), or likely type 2 MI (lT2MI; n  = 466) occurred in 508 of 4170 (12.2%) patients. The weighted odds ratio in patients on statin therapy was 1.15 [95% confidence interval (CI) 1.01 to 1.31, P  = 0.036]. During the 120-day follow-up, 192 patients (4.6%) suffered cardiovascular death and spontaneous MI. After multivariable adjustment, preoperative use of statins was associated with reduced risk; weighted hazard ratio 0.59 (95% CI 0.41 to 0.86, P  = 0.006).

CONCLUSION

Adherence to guideline-recommended statin therapy was suboptimal, particularly in women. Statin use was associated with an increased risk of PMI due to T1MI and lT2MI but reduced risk of cardiovascular death and spontaneous MI within 120 days.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT02573532.

Patient blood management programmes: keeping the ball rolling

Patient blood management programmes have been endorsed by the World Health Organization and multiple medical societies. It seems important to review the progress and results of patient blood management programmes so necessary modifications or new initiatives can be added to achieve their major goals. In this issue of the British Journal of Anaesthesia, Meybohm and colleagues show that a nationwide patient blood management programme had an impact and was potentially cost-effective in centres that previously utilised large amounts of allogeneic blood transfusions. Before implementing a programme, each institution might need to identify the area(s) of deficiency with respect to established patient blood management methods, which will warrant specific focus in subsequent clinical practice reviews.

Long-term outcomes of perioperative myocardial infarction/injury after non-cardiac surgery

AIMS

Perioperative myocardial infarction/injury (PMI) following non-cardiac surgery is a frequent cardiac complication. Better understanding of the underlying aetiologies and outcomes is urgently needed.

METHODS AND RESULTS

Aetiologies of PMIs detected within an active surveillance and response programme were centrally adjudicated by two independent physicians based on all information obtained during clinically indicated PMI work-up including cardiac imaging among consecutive high-risk patients undergoing major non-cardiac surgery in a prospective multicentre study. PMI aetiologies were hierarchically classified into 'extra-cardiac' if caused by a primarily extra-cardiac disease such as severe sepsis or pulmonary embolism; and 'cardiac', further subtyped into type 1 myocardial infarction (T1MI), tachyarrhythmia, acute heart failure (AHF), or likely type 2 myocardial infarction (lT2MI). Major adverse cardiac events (MACEs) including acute myocardial infarction, AHF (both only from day 3 to avoid inclusion bias), life-threatening arrhythmia, and cardiovascular death as well as all-cause death were assessed during 1-year follow-up. Among 7754 patients (age 45-98 years, 45% women), PMI occurred in 1016 (13.1%). At least one MACE occurred in 684/7754 patients (8.8%) and 818/7754 patients died (10.5%) within 1 year. Outcomes differed starkly according to aetiology: in patients with extra-cardiac PMI, T1MI, tachyarrhythmia, AHF, and lT2MI 51%, 41%, 57%, 64%, and 25% had MACE, and 38%, 27%, 40%, 49%, and 17% patients died within 1 year, respectively, compared to 7% and 9% in patients without PMI. These associations persisted in multivariable analysis.

CONCLUSION

At 1 year, most PMI aetiologies have unacceptably high rates of MACE and all-cause death, highlighting the urgent need for more intensive treatments.

STUDY REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02573532.

Acute heart failure after non-cardiac surgery: incidence, phenotypes, determinants and outcomes

AIMS

Primary acute heart failure (AHF) is a common cause of hospitalization. AHF may also develop postoperatively (pAHF). The aim of this study was to assess the incidence, phenotypes, determinants and outcomes of pAHF following non-cardiac surgery.

METHODS AND RESULTS

A total of 9164 consecutive high-risk patients undergoing 11 262 non-cardiac inpatient surgeries were prospectively included. The incidence, phenotypes, determinants and outcome of pAHF, centrally adjudicated by independent cardiologists, were determined. The incidence of pAHF was 2.5% (95% confidence interval [CI] 2.2-2.8%); 51% of pAHF occurred in patients without known heart failure (de novo pAHF), and 49% in patients with chronic heart failure. Among patients with chronic heart failure, 10% developed pAHF, and among patients without a history of heart failure, 1.5% developed pAHF. Chronic heart failure, diabetes, urgent/emergent surgery, atrial fibrillation, cardiac troponin elevations above the 99th percentile, chronic obstructive pulmonary disease, anaemia, peripheral artery disease, coronary artery disease, and age, were independent predictors of pAHF in the logistic regression model. Patients with pAHF had significantly higher all-cause mortality (44% vs. 11%, p < 0.001) and AHF readmission (15% vs. 2%, p < 0.001) within 1 year than patients without pAHF. After Cox regression analysis, pAHF was an independent predictor of all-cause mortality (adjusted hazard ratio [aHR] 1.7 [95% CI 1.3-2.2]; p < 0.001) and AHF readmission (aHR 2.3 [95% CI 1.5-3.7]; p < 0.001). Findings were confirmed in an external validation cohort using a prospective multicentre cohort of 1250 patients (incidence of pAHF 2.4% [95% CI 1.6-3.3%]).

CONCLUSIONS

Postoperative AHF frequently developed following non-cardiac surgery, being de novo in half of cases, and associated with a very high mortality.

Independent External Validation of a Preoperative Prediction Model for Delirium After Cardiac Surgery: A Prospective Observational Cohort Study

OBJECTIVE

This investigation provided independent external validation of an existing preoperative risk prediction model.

DESIGN

A prospective observational cohort study of patients undergoing cardiac surgery covering the period between April 16, 2018 and January 18, 2022.

SETTING

Two academic hospitals in Switzerland.

PARTICIPANTS

Adult patients (≥60 years of age) who underwent elective cardiac surgery, including coronary artery bypass graft, mitral or aortic valve replacement or repair, and combined procedures.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measure was the incidence of postoperative delirium (POD) in the intensive or intermediate care unit, diagnosed using the Intensive Care Delirium Screening Checklist. The prediction model contained 4 preoperative risk factors to which the following points were assigned: Mini-Mental State Examination (MMSE) score ≤23 received 2 points; MMSE 24-27, Geriatric Depression Scale (GDS) >4, prior stroke and/or transient ischemic attack (TIA), and abnormal serum albumin (≤3.5 or ≥4.5 g/dL) received 1 point each. The missing data were handled using multiple imputation. In total, 348 patients were included in the study. Sixty patients (17.4%) developed POD. For point levels in the prediction model of 0, 1, 2, and ≥3, the cumulative incidence of POD was 12.6%, 22.8%, 25.8%, and 35%, respectively. The validation resulted in a pooled area under the receiver operating characteristics curve of 0.60 (median CI, 0.525-0.679).

CONCLUSIONS

The evaluated predictive model for delirium after cardiac surgery in this patient cohort showed only poor discriminative capacity but fair calibration.

Conversion between the Montreal Cognitive Assessment and the Mini-Mental Status Examination

BACKGROUND

Early and accurate detection of cognitive changes using simple tools is essential for an appropriate referral to a more detailed neurocognitive assessment and for the implementation of therapeutic strategies. The Mini-Mental Status Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) are two commonly used psychometric tests for cognitive screening. Both tests have different strengths and weaknesses. Preferences regarding test selection may therefore differ among clinicians. The aim of this retrospective observational cohort study was to define corresponding scores for the MMSE and the MoCA.

METHODS

We examined the relationship between the cognitive screening tests in 803 German-speaking Memory Clinic outpatients, encompassing a wide range of neurocognitive disorders. We produced a conversion table using the equipercentile equating method with log-linear smoothing. In addition, we conducted a systematic review of existing MMSE-MoCA conversions to create a table allowing for the conversion of MoCA scores into MMSE scores and vice versa using the weighted mean method.

RESULTS

The Memory Clinic sample showed that the prediction of MMSE to MoCA was overall less accurate compared to the conversion from MoCA to MMSE. The 19 studies included after thorough literature search showed that MoCA scores were consistently lower than MMSE scores. Eleven of 19 conversion studies had addressed the conversion of the MoCA to the MMSE, while two studies converted MMSE to MoCA scores. Another six studies applied bi-directional conversions. We provide an easy-to-use table covering the entire range of scores and taking into account all currently existing conversion formulas.

CONCLUSION

The comprehensive MMSE-MoCA conversion table enables a direct comparison of cognitive test scores at screening examinations and over the course of disease in patients with neurocognitive disorders.

Renal failure: a non-cardiac source of high sensitivity cardiac troponin T

Background

Circulating high sensitivity cardiac troponin T (hs-cTnT) levels are frequently elevated in patients with end-stage renal disease (ESRD). The underlying pathophysiology is largely unknown. Currently, accumulation of hs-cTnT due to impaired renal clearance, as well as increased production caused by chronic cardiomyocyte injury is being discussed.

Purpose

The aim of this study was to assess the relative contribution of impaired renal clearance as a non-cardiac source of elevated hs-cTnT concentrations, using renal transplantation as an in vivo model of rapidly improved renal function and on a short-term basis rather unchanged cardiac pathology.

Methods

This single-centre study was a secondary analysis within a prospective active surveillance study program for perioperative myocardial infarction/injury (PMI). 42 consecutive high-risk patients undergoing renal transplantation without evidence of PMI were included. Serial creatinine and hs-cTnT (Elecsys, Roche) measurements were performed pre-transplant (baseline) and post-transplant on day (d) 1, between d2 and d5, and between d14 and d180. The effect of time and creatinine on hs-cTnT was estimated with a log-level non-linear mixed-effects model, where time and creatinine were treated as the fixed effects and subject as the random effect. Natural cubic splines were used to account for nonlinearity in the fixed effects.

Results

Baseline median serum creatinine concentration was 616 umol/L [interquartile range (IQR) 477–825], and significantly fell to 425 umol/L (IQR 313–619) on d1, 285 umol/L (IQR 194–509) on day2–5, and 116 umol/L (IQR 100–166) on d14–180 (p&lt;0.001, p&lt;0.001, and p=0.043, respectively; Figure 1A).

Pre-transplant hs-cTnT concentrations were above the 99th percentile (14ng/L) in all patients, median hs-cTnT concentration was 50 ng/L (IQR 35–70). In parallel to the fall in serum creatinine from baseline to d1, hs-cTnT concentrations significantly fell to 28 ng/L (IQR 15–40) on d1 (p&lt;0.001), and then remained constant on d2–5 (27 ng/L (IQR 18–35)), and on d14–180 (24 ng/L (IQR 19–28); Figure 1B).

The mixed-effect model showed a significant decrease of hs-cTnT between baseline and d1 (p&lt;0.001), whereas no significant change between d1 and d2 (p=0.82) occurred (Figure 2).

Conclusion

In contrast to the continuously falling serum creatinine levels, hs-cTnT concentrations reduced by about 50% only within the first 24 hours with a functional graft and then remained elevated above the 99th percentile. This suggests, that ESRD is a non-cardiac source of elevated circulating hs-cTnT concentrations, which contributes about 50%, while the other 50% seem related to chronic cardiomyocyte injury. Further studies assessing the long-term effect of renal transplantation on hs-cTnT levels and cardiac function are needed.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Swiss National Science FoundationSwiss Heart Foundation

Comparing propofol anaesthesia guided by Bispectral Index monitoring and frontal EEG wave analysis with standard monitoring in laparoscopic surgery: protocol for the 'EEG in General Anaesthesia - More Than Only a Bispectral Index' Trial, a multicentre, double-blind, randomised controlled trial

INTRODUCTION

The use of Bispectral Index (BIS) monitors for assessing depth of sedation has led to a reduction in both the incidence of awareness and anaesthetic consumption in total intravenous anaesthesia. However, these monitors are vulnerable to artefacts. In addition to the processed number, the raw frontal electroencephalogram (EEG) can be displayed as a curve on the same monitor. Anaesthesia practitioners can learn to interpret the EEG in a short tutorial and may be quicker and more accurate thanBIS in assessing anaesthesia depth by recognising EEG patterns. We hypothesise that quality of recovery (QoR) in patients undergoing laparoscopic surgery is better, if propofol is titrated by anaesthesia practitioners able to interpret the EEG.

METHODS AND ANALYSIS

This is a multicentre, double-blind (patients and outcome assessors) randomised controlled trial taking place in four Swiss hospitals. Patients aged 18 years or older undergoing laparoscopic procedures with general anaesthesia using propofol and anaesthesia practitioners with more than 2 years experience will be eligible. The primary study outcome is the difference in QoR 24 hours after surgery. Secondary outcomes are propofol consumption, incidence of postoperative nausea and vomiting (PONV) and postoperative delirium.QoR and propofol consumption are compared between both groups using a two-sample t-test. Fisher's exact test is used to compare the incidences of PONV and delirium. A total of 200 anaesthesia practitioners (and 200 patients) are required to have an 80% chance of detecting the minimum relevant difference for the QoR-15 as significant at the 5% level assuming a SD of 20.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from all responsible ethics committees (lead committee: Ethikkommission Nordwest- und Zentralschweiz, 16 January 2021). The findings of the trial will be published in a peer-reviewed journal, presented at international conferences, and may lead to a change in titrating propofol in clinical practice.

TRIAL REGISTRATION NUMBER

www.

CLINICALTRIALS

gov:NCT04105660.

Cardiovascular imaging following perioperative myocardial infarction/injury

Patients developing perioperative myocardial infarction/injury (PMI) have a high mortality. PMI work-up and therapy remain poorly defined. This prospective multicenter study included high-risk patients undergoing major non-cardiac surgery within a systematic PMI screening and clinical response program. The frequency of cardiovascular imaging during PMI work-up and its yield for possible type 1 myocardial infarction (T1MI) was assessed. Automated PMI detection triggered evaluation by the treating physician/cardiologist, who determined selection/timing of cardiovascular imaging. T1M1 was considered with the presence of a new wall motion abnormality within 30 days in transthoracic echocardiography (TTE), a new scar or ischemia within 90 days in myocardial perfusion imaging (MPI), and Ambrose-Type II or complex lesions within 7 days of PMI in coronary angiography (CA). In patients with PMI, 21% (268/1269) underwent at least one cardiac imaging modality. TTE was used in 13% (163/1269), MPI in 3% (37/1269), and CA in 5% (68/1269). Cardiology consultation was associated with higher use of cardiovascular imaging (27% versus 13%). Signs indicative of T1MI were found in 8% of TTE, 46% of MPI, and 63% of CA. Most patients with PMI did not undergo any cardiovascular imaging within their PMI work-up. If performed, MPI and CA showed high yield for signs indicative of T1MI.Trial registration: https://clinicaltrials.gov/ct2/show/NCT02573532 .

Incidence and outcomes of perioperative myocardial infarction/injury diagnosed by high-sensitivity cardiac troponin I

BACKGROUND

 Perioperative myocardial infarction/injury (PMI) diagnosed by high-sensitivity troponin (hs-cTn) T is frequent and a prognostically important complication of non-cardiac surgery. We aimed to evaluate the incidence and outcome of PMI diagnosed using hs-cTnI, and compare it to PMI diagnosed using hs-cTnT.

METHODS

We prospectively included 2455 patients at high cardiovascular risk undergoing 3111 non-cardiac surgeries, for whom hs-cTnI and hs-cTnT concentrations were measured before surgery and on postoperative days 1 and 2. PMI was defined as a composite of perioperative myocardial infarction (PMIInfarct) and perioperative myocardial injury (PMIInjury), according to the Fourth Universal Definition of Myocardial Infarction. All-cause mortality was the primary endpoint.

RESULTS

Using hs-cTnI, the incidence of overall PMI was 9% (95% confidence interval [CI] 8-10%), including PMIInfarct 2.6% (95% CI 2.0-3.2) and PMIInjury 6.1% (95% CI 5.3-6.9%), which was lower versus using hs-cTnT: overall PMI 15% (95% CI 14-16%), PMIInfarct 3.7% (95% CI 3.0-4.4) and PMIInjury 11.3% (95% CI 10.2-12.4%). All-cause mortality occurred in 52 (2%) patients within 30 days and 217 (9%) within 1 year. Using hs-cTnI, both PMIInfarct and PMIInjury were independent predictors of 30-day all-cause mortality (adjusted hazard ratio [aHR] 2.5 [95% CI 1.1-6.0], and aHR 2.8 [95% CI 1.4-5.5], respectively) and, 1-year all-cause mortality (aHR 2.0 [95% CI 1.2-3.3], and aHR 1.8 [95% CI 1.2-2.7], respectively). Overall, the prognostic impact of PMI diagnosed by hs-cTnI was comparable to the prognostic impact of PMI using hs-cTnT.

CONCLUSIONS

Using hs-cTnI, PMI is less common versus using hs-cTnT. Using hs-cTnI, both PMIInfarct and PMIInjury remain independent predictors of 30-day and 1-year mortality.

Adherence to the European Society of Cardiology/European Society of Anaesthesiology recommendations on preoperative cardiac testing and association with positive results and cardiac events: a cohort study

BACKGROUND

European Society of Cardiology/European Society of Anaesthesiology (ESC/ESA) guidelines inform cardiac workup before noncardiac surgery based on an algorithm. Our primary hypotheses were that there would be associations between (i) the groups stratified according to the algorithms and major adverse cardiac events (MACE), and (ii) over- and underuse of cardiac testing and MACE.

METHODS

This is a secondary analysis of a multicentre prospective cohort. Major adverse cardiac events were a composite of cardiac death, myocardial infarction, acute heart failure, and life-threatening arrhythmia at 30 days. For each cardiac test, pathological findings were defined a priori. We used multivariable logistic regression to measure associations.

RESULTS

We registered 359 MACE at 30 days amongst 6976 patients; classification in a higher-risk group using the ESC/ESA algorithm was associated with 30-day MACE; however, discrimination of the ESC/ESA algorithms for 30-day MACE was modest; area under the curve 0.64 (95% confidence interval: 0.61-0.67). After adjustment for sex, age, and ASA physical status, discrimination was 0.72 (0.70-0.75). Overuse or underuse of cardiac tests were not consistently associated with MACE. There was no independent association between test recommendation class and pathological findings (P=0.14 for stress imaging; P=0.35 for transthoracic echocardiography; P=0.52 for coronary angiography).

CONCLUSIONS

Discrimination for MACE using the ESC/ESA guidelines algorithms was limited. Overuse or underuse of cardiac tests was not consistently associated with cardiovascular events. The recommendation class of preoperative cardiac tests did not influence their yield.

CLINICAL TRIAL REGISTRATION

NCT02573532.

[Prospective Cohort Study of In-Hospital Patients Undergoing Ophthalmic Surgery for the Validation of ClassIntra: Classification of Intraoperative Adverse Events]

BACKGROUND

To the best of our knowledge, there is no validated classification to assess intraoperative adverse events (iAEs) in ophthalmic surgery. ClassIntra is a newly developed classification for surgery- and anaesthesia-related iAEs that has been recently validated in various surgical disciplines, but not in ophthalmic surgery. We aim to assess the validity and practicability of ClassIntra in patients undergoing ophthalmic surgery.

METHODS

A consecutive sample of in-hospital patients undergoing any type of ophthalmic surgery was included in this single-centre prospective cohort study. iAEs were classified using ClassIntra, consisting of 5 severity grades according to the symptoms of the patient and the required treatment. All patients were followed for two weeks to record all postoperative adverse events according to Clavien-Dindo. The primary endpoint was the risk-adjusted association between the most severe iAE and the weighted sum of all postoperative adverse events within the two-week follow-up using the Comprehensive Complication Index (CCI). In addition, ophthalmologists and anaesthesiologists were asked to complete an online survey assessing the severity of iAEs for 10 fictitious clinical case scenarios. Reliability was assessed by comparing the clinicians' ratings to the prespecified benchmark rating of the study team.

RESULTS

In this study, 100 in-hospital patients with an average age of 64 years (SD 15) were included. The majority of all patients were ASA II (n = 53, 53%) or III (n = 42, 42%). Thirty-two iAEs were recorded in 22 patients (17 grade I, 12 grade II, 3 grade III). Ninety-four postoperative adverse events occurred in 50 patients (44 grade I, 36 grade II, 14 grade IIIa). We found a mean difference in CCI of 2,1 (95% confidence interval [CI] - 2,5 to 6,8) per one unit increase in severity grades of ClassIntra. Fifty ophthalmologists and anaesthesiologists completed the online survey (response rate 54%). The intraclass correlation coefficient was 0,79 (95% CI 0,64 to 0,94).

CONCLUSIONS

The application of ClassIntra during daily routine in ophthalmic surgery showed the usefulness and practicability of this classification for the standardised assessment of intraoperative adverse events. Although construct validity could not be demonstrated, the good reliability in the survey's rating underlines the criterion validity of this newly developed classification in ophthalmic surgery.

Spatial and Temporal Pattern of Ischemia and Abnormal Vascular Function Following Traumatic Brain Injury

Question

How does ¹⁵oxygen positron emission tomography characterization of cerebral physiology after traumatic brain injury inform clinical practice?

Findings

In this single-center observational cohort study of 68 patients and 27 control participants, early ischemia was common in patients, but hyperemia coexisted in different brain regions. Cerebral blood volume was consistently increased, despite low cerebral blood flow.

Meaning

Per this analysis, pathophysiologic heterogeneity indicates that bedside physiological monitoring with devices that measure global (jugular venous saturation) or focal (tissue oximetry) brain oxygenation should be interpreted with caution.

Importance

Ischemia is an important pathophysiological mechanism after traumatic brain injury (TBI), but its incidence and spatiotemporal patterns are poorly characterized.

Objective

To comprehensively characterize the spatiotemporal changes in cerebral physiology after TBI.

Design, Setting, and Participants

This single-center cohort study uses ¹⁵oxygen positron emission tomography data obtained in a neurosciences critical care unit from February 1998 through July 2014 and analyzed from April 2018 through August 2019. Patients with TBI requiring intracranial pressure monitoring and control participants were recruited.

Exposures

Cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen metabolism (CMRO₂), and oxygen extraction fraction.

Main Outcomes and Measures

Ratios (CBF/CMRO₂ and CBF/CBV) were calculated. Ischemic brain volume was compared with jugular venous saturation and brain tissue oximetry.

Results

A total of 68 patients with TBI and 27 control participants were recruited. Results from 1 patient with TBI and 7 health volunteers were excluded. Sixty-eight patients with TBI (13 female [19%]; median [interquartile range (IQR)] age, 29 [22-47] years) underwent 90 studies at early (day 1 [n = 17]), intermediate (days 2-5 [n = 54]), and late points (days 6-10 [n = 19]) and were compared with 20 control participants (5 female [25%]; median [IQR] age, 43 [31-47] years). The global CBF and CMRO₂ findings for patients with TBI were less than the ranges for control participants at all stages (median [IQR]: CBF, 26 [22-30] mL/100 mL/min vs 38 [29-49] mL/100 mL/min; P < .001; CMRO₂, 62 [55-71] μmol/100 mL/min vs 131 [101-167] μmol/100 mL/min; P < .001). Early CBF reductions showed a trend of high oxygen extraction fraction (suggesting classical ischemia), but this was inconsistent at later phases. Ischemic brain volume was elevated even in the absence of intracranial hypertension and highest at less than 24 hours after TBI (median [IQR], 36 [10-82] mL), but many patients showed later increases (median [IQR] 6-10 days after TBI, 24 [4-42] mL; across all points: patients, 10 [5-39] mL vs control participants, 1 [0-3] mL; P < 001). Ischemic brain volume was a poor indicator of jugular venous saturation and brain tissue oximetry. Patients’ CBF/CMRO₂ ratio was higher than controls (median [IQR], 0.42 [0.35-0.49] vs 0.3 [0.28-0.33]; P < .001) and their CBF/CBV ratio lower (median [IQR], 7.1 [6.4-7.9] vs 12.3 [11.0-14.0]; P < .001), suggesting abnormal flow-metabolism coupling and vascular reactivity. Patients’ CBV was higher than controls (median [IQR], 3.7 [3.4-4.1] mL/100 mL vs 3.0 [2.7-3.6] mL/100 mL; P < .001); although values were lower in patients with intracranial hypertension, these were still greater than controls (median [IQR], 3.7 [3.2-4.0] vs 3.0 [2.7-3.6] mL/100 mL; P = .002), despite more profound reductions in partial pressure of carbon dioxide (median [IQR], 4.3 [4.1-4.6] kPa vs 4.7 [4.3-4.9] kPa; P = .001).

Conclusions and Relevance

Ischemia is common early, detectable up to 10 days after TBI, possible without intracranial hypertension, and inconsistently detected by jugular or brain tissue oximetry. There is substantial between-patient and within-patient pathophysiological heterogeneity; ischemia and hyperemia commonly coexist, possibly reflecting abnormalities in flow-metabolism coupling. Increased CBV may contribute to intracranial hypertension but can coexist with abnormal CBF/CBV ratios. These results emphasize the need to consider cerebrovascular pathophysiological complexity when managing patients with TBI.

Association between self-reported functional capacity and major adverse cardiac events in patients at elevated risk undergoing noncardiac surgery: a prospective diagnostic cohort study

BACKGROUND

Perioperative cardiovascular guidelines endorse functional capacity estimation, based on 'cut-off' daily activities for risk assessment and climbing two flights of stairs to approximate 4 metabolic equivalents. We assessed the association between self-reported functional capacity and postoperative cardiac events.

METHODS

Consecutive patients at elevated cardiovascular risk undergoing in-patient noncardiac surgery were included in this predefined secondary analysis. Self-reported ability to walk up two flights of stairs was extracted from electronic charts. The primary endpoint was a composite of cardiac death and cardiac events at 30 days. Secondary endpoints included the same composite at 1 yr, all-cause mortality, and myocardial injury.

RESULTS

Among the 4560 patients, mean (standard deviation) age 73 (SD 8 yr) yr, classified as American Society of Anesthesiologists physical status ≥3 in 61% (n=2786/4560), the 30-day and 1-yr incidences of major adverse cardiac events were 5.7% (258/4560) and 11.2% (509/4560), respectively. Functional capacity less than two flights of stairs was associated with the 30-day composite endpoint (adjusted hazard ratio 1.63, 95% confidence interval [CI] 1.23-2.15) and all other endpoints. The addition of functional capacity information to the revised cardiac risk index (RCRI) significantly improved risk classification (functional capacity plus RCRI vs RCRI: net reclassification improvement [NRI]_Events 6.2 [95% CI 3.6-9.9], NRI_Nonevents19.2 [95% CI 18.1-20.0]).

CONCLUSIONS

In patients at high cardiovascular risk undergoing noncardiac surgery, self-reported functional capacity less than two flights of stairs was independently associated with major adverse cardiac events and all-cause mortality at 30 days and 1 yr. The addition of self-reported functional capacity to surgical and clinical risk improved risk classification.

CLINICAL TRIAL REGISTRATION

INCT 02573532.

Prospective validation of classification of intraoperative adverse events (ClassIntra): international, multicentre cohort study

OBJECTIVE

To prospectively assess the construct and criterion validity of ClassIntra version 1.0, a newly developed classification for assessing intraoperative adverse events.

DESIGN

International, multicentre cohort study.

SETTING

18 secondary and tertiary centres from 12 countries in Europe, Oceania, and North America.

PARTICIPANTS

The cohort study included a representative sample of 2520 patients in hospital having any type of surgery, followed up until discharge. A follow-up to assess mortality at 30 days was performed in 2372 patients (94%). A survey was sent to a representative sample of 163 surgeons and anaesthetists from participating centres.

MAIN OUTCOME MEASURES

Intraoperative complications were assessed according to ClassIntra. Postoperative complications were assessed daily until discharge from hospital with the Clavien-Dindo classification. The primary endpoint was construct validity by investigating the risk adjusted association between the most severe intraoperative and postoperative complications, measured in a multivariable hierarchical proportional odds model. For criterion validity, inter-rater reliability was evaluated in a survey of 10 fictitious case scenarios describing intraoperative complications.

RESULTS

Of 2520 patients enrolled, 610 (24%) experienced at least one intraoperative adverse event and 838 (33%) at least one postoperative complication. Multivariable analysis showed a gradual increase in risk for a more severe postoperative complication with increasing grade of ClassIntra: ClassIntra grade I versus grade 0, odds ratio 0.99 (95% confidence interval 0.69 to 1.42); grade II versus grade 0, 1.39 (0.97 to 2.00); grade III versus grade 0, 2.62 (1.31 to 5.26); and grade IV versus grade 0, 3.81 (1.19 to 12.2). ClassIntra showed high criterion validity with an intraclass correlation coefficient of 0.76 (95% confidence interval 0.59 to 0.91) in the survey (response rate 83%).

CONCLUSIONS

ClassIntra is the first prospectively validated classification for assessing intraoperative adverse events in a standardised way, linking them to postoperative complications with the well established Clavien-Dindo classification. ClassIntra can be incorporated into routine practice in perioperative surgical safety checklists, or used as a monitoring and outcome reporting tool for different surgical disciplines. Future studies should investigate whether the tool is useful to stratify patients to the appropriate postoperative care, to enhance the quality of surgical interventions, and to improve long term outcomes of surgical patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03009929.

Study protocol for a prospective randomised double-blind placebo-controlled clinical trial investigating a Better Outcome with Melatonin compared to Placebo Administered to normalize sleep-wake cycle and treat hypoactive ICU Delirium: the Basel BOMP-AID study

INTRODUCTION

Delirium is frequently observed in the intensive care unit (ICU) population, in particular. Until today, there is no evidence for any reliable pharmacological intervention to treat delirium. The Basel BOMP-AID (Better Outcome with Melatonin compared to Placebo Administered to normalize sleep-wake cycle and treat hypoactive ICU Delirium) randomised trial targets improvement of hypoactive delirium therapy in critically ill patients and will be conducted as a counterpart to the Basel ProDex Study (Study Protocol, BMJ Open, July 2017) on hyperactive and mixed delirium. The aim of the BOMP-AID trial is to assess the superiority of melatonin to placebo for the treatment of hypoactive delirium in the ICU. The study hypothesis is based on the assumption that melatonin administered at night restores a normal circadian rhythm, and that restoration of a normal circadian rhythm will cure delirium.

METHODS AND ANALYSIS

The Basel BOMP-AID study is an investigator-initiated, single-centre, randomised controlled clinical trial for the treatment of hypoactive delirium with the once daily oral administration of melatonin 4 mg versus placebo in 190 critically ill patients. The primary outcome measure is delirium duration in 8-hour shifts. Secondary outcome measures include delirium-free days and death at 28 days after study inclusion, number of ventilator days, length of ICU and hospital stay, and sleep quality. Patients will be followed after 3 and 12 months for activities of daily living and mortality assessment. Sample size was calculated to demonstrate superiority of melatonin compared with placebo regarding the duration of delirium. Results will be presented using an intention-to-treat approach.

ETHICS AND DISSEMINATION

This study has been approved by the Ethics Committee of Northwestern and Central Switzerland and will be conducted in compliance with the protocol, the current version of the Declaration of Helsinki, the International Conference on Harmonisation (ICH) of technical requirements for registration of pharmaceuticals for human use; Good Clinical Practice (GCP) or ISO EN 14155 (as far as applicable), as well as all national legal and regulatory requirements. Study results will be presented in international conferences and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03438526.

PROTOCOL VERSION

Clinical Study Protocol Version 3, 10.03.2019.

Enhanced diagnostic accuracy for neurocognitive disorders: a revised cut-off approach for the Montreal Cognitive Assessment

Background

The Montreal Cognitive Assessment (MoCA) has good sensitivity for mild cognitive impairment, but specificity is low when the original cut-off (25/26) is used. We aim to revise the cut-off on the German MoCA for its use in clinical routine.

Methods

Data were analyzed from 496 Memory Clinic outpatients (447 individuals with a neurocognitive disorder; 49 with cognitive normal findings) and from 283 normal controls. Cut-offs were identified based on (a) Youden’s index and (b) the 10th percentile of the control group.

Results

A cut-off of 23/24 on the MoCA had better correct classification rates than the MMSE and the original MoCA cut-off. Compared to the original MoCA cut-off, the cut-off of 23/24 points had higher specificity (92% vs 63%), but lower sensitivity (65% vs 86%). Introducing two separate cut-offs increased diagnostic accuracies with 92% specificity (23/24 points) and 91% sensitivity (26/27 points). Scores between these two cut-offs require further examinations.

Conclusions

Using two separate cut-offs for the MoCA combined with scores in an indecisive area enhances the accuracy of cognitive screening.

The Montreal Cognitive Assessment: Normative Data from a German-Speaking Cohort and Comparison with International Normative Samples

Background:

The Montreal Cognitive Assessment (MoCA) is used to evaluate multiple cognitive domains in elderly individuals. However, it is influenced by demographic characteristics that have yet to be adequately considered.

Objective:

The aim of our study was to investigate the effects of age, education, and sex on the MoCA total score and to provide demographically adjusted normative values for a German-speaking population.

Methods:

Subjects were recruited from a registry of healthy volunteers. Cognitive health was defined using the Mini-Mental State Examination (score ≥27/30 points) and the Consortium to Establish a Registry for Alzheimer’s Disease-Neuropsychological Assessment Battery (total score ≥85.9 points). Participants were assessed with the German version of the MoCA. Normative values were developed based on regression analysis. Covariates were chosen using the Predicted Residual Sums of Squares approach.

Results:

The final sample consisted of 283 participants (155 women, 128 men; mean (SD) age = 73.8 (5.2) years; education = 13.6 (2.9) years). Thirty-one percent of participants scored below the original cut-off (<26/30 points). The MoCA total score was best predicted by a regression model with age, education, and sex as covariates. Older age, lower education, and male sex were associated with a lower MoCA total score (p < 0.001).

Conclusion:

We developed a formula to provide demographically adjusted standard scores for the MoCA in a German-speaking population. A comparison with other MoCA normative studies revealed considerable differences with respect to selection of volunteers and methods used to establish normative data.

Hypocapnia after traumatic brain injury: how does it affect the time constant of the cerebral circulation?

The time constant of the cerebral arterial bed (“tau”) estimates how fast the blood entering the brain fills the arterial vascular sector. Analogous to an electrical resistor–capacitor circuit, it is expressed as the product of arterial compliance (Ca) and cerebrovascular resistance (CVR). Hypocapnia increases the time constant in healthy volunteers and decreases arterial compliance in head trauma. How the combination of hyocapnia and trauma affects this parameter has yet to be studied. We hypothesized that in TBI patients the intense vasoconstrictive action of hypocapnia would dominate over the decrease in compliance seen after hyperventilation. The predominant vasoconstrictive response would maintain an incoming blood volume in the arterial circulation, thereby lengthening tau. We retrospectively analyzed recordings of intracranial pressure (ICP), arterial blood pressure (ABP), and blood flow velocity (FV) obtained from a cohort of 27 severe TBI patients [(39/30 years (median/IQR), 5 women; admission GCS 6/5 (median/IQR)] studied during a standard clinical CO₂ reactivity test. The reactivity test was performed by means of a 50-min increase in ventilation (20% increase in respiratory minute volume). CVR and Ca were estimated from these recordings, and their product calculated to find the time constant. CVR significantly increased [median CVR pre-hypocapnia/during hypocapnia: 1.05/1.35 mmHg/(cm³/s)]. Ca decreased (median Ca pre-hypocapnia/during hypocapnia: 0.130/0.124 arbitrary units) to statistical significance (p = 0.005). The product of these two parameters resulted in a significant prolongation of the time constant (median tau pre-hypocapnia/during hypocapnia: 0.136 s/0.152 s, p ˂ .001). Overall, the increase in CVR dominated over the decrease in compliance, hence tau was longer. We demonstrate a significant increase in the time constant of the cerebral circulation during hypocapnia after severe TBI, and attribute this to an increase in cerebrovascular resistance which outweighs the decrease in cerebral arterial bed compliance.

Efficacy and safety of carbetocin given as an intravenous bolus compared with short infusion for Caesarean section - double-blind, double-dummy, randomized controlled non-inferiority trial

Background

Carbetocin is a synthetic oxytocin-analogue, which should be administered as bolus according to manufacturer's recommendations. A higher speed of oxytocin administration leads to increased cardiovascular side-effects. It is unclear whether carbetocin administration as short infusion has the same efficacy on uterine tone compared with bolus administration and whether haemodynamic parameters differ.

Methods

In this randomized, double-blind, non-inferiority trial, women undergoing planned or unplanned Caesarean section (CS) under regional anaesthesia received a bolus and a short infusion, only one of which contained carbetocin 100 mcg (double dummy). Obstetricians quantified uterine tone two, three, five and 10 min after cord-clamping by manual palpation using a linear analogue scale from 0 to 100. We evaluated whether the lower limit of the 95% CI of the difference in maximum uterine tone within the first five min after cord-clamping did not include the pre-specified non-inferiority limit of -10.

Results

Between December 2014 and November 2015, 69 patients were randomized to receive carbetocin as bolus and 71 to receive it as short infusion. Maximal uterine tone was 89 in the bolus and 88 in the short infusion group (mean difference -1.3, 95% CI -5.7 to 3.1). Bp, calculated blood loss, use of additional uterotonics, and side-effects were comparable.

Conclusions

Administration of carbetocin as short infusion does not compromise uterine tone and has similar cardiovascular side-effects as a slow i.v. bolus. In accordance with current recommendations for oxytocin, carbetocin can safely be administered as short -infusion during planned or unplanned CS.

Clinical trial registration

ClinicalTrials.gov NCT02221531 and www.kofam.ch SNCTP000001197.

Transiente und permanente kognitive Defizite nach chirurgischen Operationen

Zusammenfassung. Eine von Ärzten oft unterschätze Befürchtung von älteren Patienten ist das Auftreten von vorübergehenden, oder sogar bleibenden, kognitiven Einbussen als Folge einer Operation. Als Anästhesist wird man mit dieser Frage oft konfrontiert, da im Allgemeinen davon ausgegangen wird, dass solche kognitive Defizite eine direkte Folge der Narkose sind. In diesem Artikel werden die möglichen kognitiven Folgen einer Operation und ihr zeitlicher Verlauf dargestellt. Zusätzlich werden die Risikofaktoren und die Pathophysiologie, soweit bekannt, diskutiert. Im Rahmen dieser Übersicht sprechen wir von transienten Störungen bei kognitiven Problemen, die in den ersten drei bis maximal sechs Monaten nach einer Operation auftreten. Die beiden Formen der transienten postoperativen kognitiven Störungen, die in der Praxis unterschieden werden, sind das postoperative Delir und die postoperative kognitive Dysfunktion. Störungen, welche 12 bis 24 Monate nach Operationen persistieren, werden als permanent definiert.

Individualizing Thresholds of Cerebral Perfusion Pressure Using Estimated Limits of Autoregulation

OBJECTIVES

In severe traumatic brain injury, cerebral perfusion pressure management based on cerebrovascular pressure reactivity index has the potential to provide a personalized treatment target to improve patient outcomes. So far, the methods have focused on identifying "one" autoregulation-guided cerebral perfusion pressure target-called "cerebral perfusion pressure optimal". We investigated whether a cerebral perfusion pressure autoregulation range-which uses a continuous estimation of the "lower" and "upper" cerebral perfusion pressure limits of cerebrovascular pressure autoregulation (assessed with pressure reactivity index)-has prognostic value.

DESIGN

Single-center retrospective analysis of prospectively collected data.

SETTING

The neurocritical care unit at a tertiary academic medical center.

PATIENTS

Data from 729 severe traumatic brain injury patients admitted between 1996 and 2016 were used. Treatment was guided by controlling intracranial pressure and cerebral perfusion pressure according to a local protocol.

INTERVENTIONS

None.

METHODS AND MAIN RESULTS

Cerebral perfusion pressure-pressure reactivity index curves were fitted automatically using a previously published curve-fitting heuristic from the relationship between pressure reactivity index and cerebral perfusion pressure. The cerebral perfusion pressure values at which this "U-shaped curve" crossed the fixed threshold from intact to impaired pressure reactivity (pressure reactivity index = 0.3) were denoted automatically the "lower" and "upper" cerebral perfusion pressure limits of reactivity, respectively. The percentage of time with cerebral perfusion pressure below (%cerebral perfusion pressure < lower limit of reactivity), above (%cerebral perfusion pressure > upper limit of reactivity), or within these reactivity limits (%cerebral perfusion pressure within limits of reactivity) was calculated for each patient and compared across dichotomized Glasgow Outcome Scores. After adjusting for age, initial Glasgow Coma Scale, and mean intracranial pressure, percentage of time with cerebral perfusion pressure less than lower limit of reactivity was associated with unfavorable outcome (odds ratio %cerebral perfusion pressure < lower limit of reactivity, 1.04; 95% CI, 1.02-1.06; p < 0.001) and mortality (odds ratio, 1.06; 95% CI, 1.04-1.08; p < 0.001).

CONCLUSIONS

Individualized autoregulation-guided cerebral perfusion pressure management may be a plausible alternative to fixed cerebral perfusion pressure threshold management in severe traumatic brain injury patients. Prospective randomized research will help define which autoregulation-guided method is beneficial, safe, and most practical.

Associations Between Impaired Cerebral Blood Flow Autoregulation, Cerebral Oxygenation, and Biomarkers of Brain Injury and Postoperative Cognitive Dysfunction in Elderly Patients After Major Noncardiac Surgery

BACKGROUND

Increasing evidence links postoperative cognitive dysfunction (POCD) to surgery and anesthesia. POCD is recognized as an important neuropsychological adverse outcome in surgical patients, particularly the elderly. This prospective cohort study aimed to investigate whether POCD is associated with impaired intraoperative cerebral autoregulation and oxygenation, and increased levels of biomarkers of brain injury.

METHODS

Study subjects were patients ≥65 years of age scheduled for major noncardiac surgery. Cognitive function was assessed before and 1 week after surgery. POCD was diagnosed if a decline of >1 standard deviation of z-scores was present in ≥2 variables of the test battery. The incidence of POCD 1 week after surgery was modeled as a multivariable function of the index of autoregulation (MxA) and tissue oxygenation index (TOI), adjusting for baseline neuropsychological assessment battery (Consortium to Establish a Registry for Alzheimer's Disease-Neuropsychological Assessment Battery [CERAD-NAB]) total score and the maximum C-reactive protein (CRP) concentration. The biomarkers of brain injury neuron-specific enolase and S100β protein, age, and level of education were included in secondary multivariable logistic regression analyses.

RESULTS

Of the 82 patients who completed the study, 38 (46%) presented with POCD 1 week after surgery. In the multivariable regression analysis, higher intraoperative MxA (odds ratio [OR; 95% confidence interval (CI)], 1.39 [1.01-1.90] for an increase of 0.1 units, P = .08 after Bonferroni adjustment), signifying less effective autoregulation, was not associated with higher odds of POCD. The univariable logistic regression model for MxA yielded an association with POCD (OR [95% CI], 1.44 [1.06-1.95], P = .020). Tissue oxygenation index (1.12 [0.41-3.01] for an increase of 10%, P = 1.0 after Bonferroni adjustment) and baseline CERAD-NAB total score (0.80 [0.45-1.42] for an increase of 10 points, P = .45) did not affect the odds of POCD. POCD was associated with elevated CRP on postoperative day 2 (median [interquartile range]; 175 [81-294] vs 112 [62-142] mg/L, P = .033); however, the maximum CRP value (OR [95% CI], 1.35 [0.97-1.87] for a 2-fold increase, P = .07) had no distinct effect on POCD.

CONCLUSIONS

Impairment of intraoperative cerebral blood flow autoregulation is not predictive of early POCD in elderly patients, although secondary analyses indicate that an association probably exists.

Comparison of propofol and dexmedetomidine infused overnight to treat hyperactive and mixed ICU delirium: a protocol for the Basel ProDex clinical trial

BACKGROUND/OBJECTIVES

Delirium is a neurobehavioural disturbance that frequently develops particularly in the intensive care unit (ICU) population. It was first described more than half a century ago, where it was already discovered as a state that might come along with serious complications such as prolonged ICU and hospital stay, reduced quality of life and increased mortality. However, in most cases, there is still lack of proof for causal relationship. Its presence frequently remains unrecognised due to suggested predominance of the hypoactive form. Furthermore, in the general ICU population, it has been shown that the duration of delirium is associated with worse long-term cognitive function. Due to the multifactorial origin of delirium, we have several but no incontestable treatment options. Nonetheless, delirium bears a high burden for patient, family members and the medical care team.The Basel ProDex Study targets improvement of hyperactive and mixed delirium therapy in critically ill patients. We will focus on reducing the duration and severity of delirium by implementing dexmedetomidine into the treatment plan. Dexmedetomidine compared with other sedatives shows fewer side effects representing a better risk profile for delirium treatment in general. This could further contribute to higher patient safety.The aim of the BaProDex Trial is to assess the superiority of dexmedetomidine to propofol for treatment of hyperactive and mixed delirium in the ICU. We hypothesise that dexmedetomidine, compared with propofol administered at night, shortens both the duration and severity of delirium.

METHODS/DESIGN

The Basel ProDex Study is an investigator-initiated, one-institutional, two-centre randomised controlled clinical trial for the treatment of delirium with dexmedetomidine versus propofol in 316 critically ill patients suffering from hyperactive and mixed delirium. The primary outcome measure is delirium duration in hours. Secondary outcomes include delirium-free days at day 28, death at day 28, delirium severity, amount of ventilator days, amount of rescue sedation with haloperidol, length of ICU and hospital stay, and pharmaceutical economic analysis of the treatments. Sample size was estimated to be able to show the superiority of dexmedetomidine compared with propofol regarding the duration of delirium in hours. The trial will be externally monitored according to good clinical practice (GCP) requirements. There are no interim analyses planned for this trial.

ETHICS AND DISSEMINATION

This study will be conducted in compliance with the protocol, the current version of the Declaration of Helsinki, the International Conference on Harmonization- Good Clinical Practice (ICH-GCP) or Europäische Norm International Organization for Standardization (ISO EN 14155; as far as applicable) as well as all national legal and regulatory requirements. Only the study team will have access to trial specific data. Anonymisation will be achieved by a unique patient identification code. Trial data will be archived for a minimum of 10 years after study termination. We plan to publish the data in a major peer-reviewed clinical journal.

TRIALS REGISTRATION

ClinicalTrials.gov Identifier: NCT02807467 PROTOCOL VERSION: Clinical Study Protocol Version 2, 16.08.2016.

Independent Predictors of the Duration and Overall Burden of Postoperative Delirium After Cardiac Surgery in Adults: An Observational Cohort Study

OBJECTIVE

Postoperative delirium (POD) is a common complication after cardiac surgery and is associated with increased patient morbidity and mortality. The objective of this study was to identify risk factors for long duration and overall burden of POD after cardiac surgery.

DESIGN

One-year, single-center, retrospective, observational cohort study.

SETTING

University hospital.

PARTICIPANTS

Adult patients undergoing cardiac surgery with cardiopulmonary bypass in 2013.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were screened for POD using the Intensive Care Delirium Screening Checklist. The primary outcome measure was the incidence of POD. Secondary outcome measures were the duration of POD and the area under the curve determined using the Intensive Care Delirium Screening Checklist score over time. Independent predictors of POD were estimated in multivariable logistic regression models. Hospital length of stay, medications, and outcome data also were analyzed. Among the 656 patients included in the cohort, 618 were analyzed. The overall incidence of POD was 39%. Older patient age (odds ratio [95% confidence interval]) 1.06 [1.04-1.09] for an increase of 1 year, p < 0.001); low preoperative serum albumin (1.08 [1.03-1.13] for a decrease of 1 g/L, p < 0.001); a history of atrial fibrillation (2.30 [1.30-4.09], p = 0.004); perioperative stroke (6.27 [1.54-43.64], p = 0.008); ascending aortic replacement surgery (2.99 [1.50-6.05], p = 0.002); longer duration of procedure (1.37 [1.16-1.63] for an increase of 1 hour, p < 0.001); and increased postoperative C-reactive protein concentration (2.16 [1.49-3.16] for a 2-fold increase, p < 0.001) were associated with higher odds of POD. Among patients affected by POD, older age, perioperative stroke, longer procedure time, and increased postoperative C-reactive protein were consistently predictive of longer duration of POD and greater area under the curve.

CONCLUSIONS

Known risk factors for the development of POD after cardiac surgery also are predictive of prolonged duration and high overall burden of POD.

Case Report: Emergency awake craniotomy for cerebral abscess in a patient with unrepaired cyanotic congenital heart disease

We report the case of a 39-year-old male with complex cyanotic congenital heart disease undergoing emergency craniotomy for a cerebral abscess. Maintenance of intraoperative hemodynamic stability and adequate tissue oxygenation during anesthesia may be challenging in patients with cyanotic congenital heart disease. In this case, we decided to perform the surgery as an awake craniotomy after interdisciplinary consensus. We discuss general aspects of anesthetic management during awake craniotomy and specific concerns in the perioperative care of patients with congenital heart disease.

Association between changes in cerebral grey matter volume and postoperative cognitive dysfunction in elderly patients: study protocol for a prospective observational cohort study

Background

Cognitive decline is frequently observed in elderly patients after major surgery. The pathophysiology of postoperative cognitive dysfunction (POCD) remains unclear. The aim of our investigation is to identify potential associations between brain volume change and POCD in elderly patients undergoing major surgery.

Methods

This is a prospective observational cohort study approved by the regional ethics board. We intend to compare specific brain volumes (hippocampus, lateral ventricle, total grey matter volume, regional cortical thickness) on magnetic resonance imaging and cognitive functions determined by a neuropsychological assessment battery in 70 study participants aged ≥65 years before and 3 and 12 months after major noncardiac surgery. Thirty volunteers will be included as matched nonsurgical controls. The primary endpoint of the study is the change in hippocampal volume over time in patients with and without POCD. The secondary endpoint is the correlation between the change in cerebral volume and cognitive function. We will follow the STROBE guidelines for reporting the results of observational studies.

Discussion

We hypothesize that surgery under general anesthesia is associated with a loss of cerebral grey matter, and that the degree of postoperative cognitive dysfunction correlates with the extent of atrophy in areas of the brain that are relevant for cognitive functions. The validation of reproducible anatomical biomarkers, such as the specific brain volumes examined in our cohort, may serve to evaluate the effect of preventive strategies and treatment interventions for POCD in follow-up studies.

Trial registration

Clinicaltrials.gov NCT02045004. Registered 22 January 2014. Kofam.ch SNCTP000001751. Registered 21 April 2016 (retrospectively registered).

Efficacy and safety of carbetocin applied as an intravenous bolus compared to as a short-infusion for caesarean section: study protocol for a randomised controlled trial

BACKGROUND

The two most commonly used uterotonic drugs in caesarean section are oxytocin and carbetocin, a synthetic oxytocin analogue. Carbetocin has a longer half-life when compared to oxytocin, resulting in a reduced use of additional uterotonics. Oxytocin is known to cause fewer cardiovascular side effects when administered as a short-infusion compared to as an intravenous bolus. Based on these findings, we aim at comparing carbetocin 100 mcg given as a slow intravenous bolus with carbetocin 100 mcg applied as a short-infusion in 100 ml 0.9 % sodium chloride in women undergoing a planned or unplanned caesarean delivery. We hypothesise uterine contraction not to be inferior to a bolus application (primary efficacy endpoint) and greater haemodynamic stability to be achieved after a short-infusion than after a bolus administration, as measured by heart rate and mean arterial blood pressure (primary safety endpoint).

METHODS/DESIGN

This is a prospective, double-blind, randomised controlled, investigator-initiated, non-inferiority trial taking place at the University Hospital Basel, Switzerland. Uterine tone is quantified by manual palpation by the obstetrician using a linear analogue scale from 0 to 100 at 2, 3, 5 and 10 minutes after cord clamping. We will evaluate whether the lower limit of the confidence interval for the difference of the maximal uterine tone within the first 5 minutes after cord clamping between both groups does not include the pre-specified non-inferiority limit of -10. Both haemodynamic secondary endpoints will be analysed using a linear regression model, adjusting for the baseline value and the dosage of vasoactive drug given between cord clamping and 1 minute thereafter, in order to investigate superiority of a short-infusion as compared to a bolus application. We will follow the extension of CONSORT guidelines for reporting the results of non-inferiority trials.

DISCUSSION

Haemodynamic stability and adequate uterine tone are important outcomes in caesarean sections. The results of this trial may be used to optimise these factors and thereby increase patient safety due to a reduction in cardiovascular side effects.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02221531 on 19 August 2014 and www.kofam.ch SNCTP000001197 on 15 November 2014.

Doppler flow velocity and intra-cranial pressure: responses to short-term mild hypocapnia help to assess the pressure-volume relationship after head injury

To anticipate an increase in intra-cranial pressure (ICP), information about pressure-volume (p/v) compliance is required. ICP monitoring often fails at this task after head injury. Could a test that transiently shifts intra-cranial blood volume produce consistent information about the p/v relationship? Doppler flow velocities in the middle cerebral arteries (left: 80.8 ± 34.7 cm/s; right: 65.9 ± 28.0 cm/s) and ICP (16.4 ± 6.7 mm Hg) were measured in 29 patients with head injury, before and during moderate hypocapnia (4.4 ± 3.0 kPa). The ratio of vasomotor response to change in ICP differed between those with high (left: 14.8 ± 6.9, right: 14.4 ± 6.6 cm/s/kPa/mm Hg) and low (left: 1.8 ± 0.6, right: 2.2 ± 0.9 cm/s/kPa/mm g) intra-cranial compliance. Additionally, the ratio identified 12 patients deviating from the classic non-linear p/v curve (left: 5.7 ± 1.3, right: 5.8 ± 1.0 cm/s/kPa/mm Hg). They exhibited an almost proportional relationship between vasomotor and ICP responses (R = 0.69, p < 0.01). Results suggest that a test that combines the responses of two intra-cranial compartments may provide consistent information about intra-cranial p/v compliance, even if the parameters derived from ICP monitoring are inconclusive.

Transcranial Doppler pulsatility index: what it is and what it isn't

BACKGROUND

Transcranial Doppler (TCD) pulsatility index (PI) has traditionally been interpreted as a descriptor of distal cerebrovascular resistance (CVR). We sought to evaluate the relationship between PI and CVR in situations, where CVR increases (mild hypocapnia) and decreases (plateau waves of intracranial pressure-ICP).

METHODS

Recordings from patients with head-injury undergoing monitoring of arterial blood pressure (ABP), ICP, cerebral perfusion pressure (CPP), and TCD assessed cerebral blood flow velocities (FV) were analyzed. The Gosling pulsatility index (PI) was compared between baseline and ICP plateau waves (n = 20 patients) or short term (30-60 min) hypocapnia (n = 31). In addition, a modeling study was conducted with the "spectral" PI (calculated using fundamental harmonic of FV) resulting in a theoretical formula expressing the dependence of PI on balance of cerebrovascular impedances.

RESULTS

PI increased significantly (p < 0.001) while CVR decreased (p < 0.001) during plateau waves. During hypocapnia PI and CVR increased (p < 0.001). The modeling formula explained more than 65% of the variability of Gosling PI and 90% of the variability of the "spectral" PI (R = 0.81 and R = 0.95, respectively).

CONCLUSION

TCD pulsatility index can be easily and quickly assessed but is usually misinterpreted as a descriptor of CVR. The mathematical model presents a complex relationship between PI and multiple haemodynamic variables.

Time constant of the cerebral arterial bed in normal subjects

The time constant of cerebral arterial bed (in brief time constant) is a product of brain arterial compliance (C(a)) and resistance (CVR). We tested the hypothesis that in normal subjects, changes in end-tidal CO(2) (EtCO(2)) affect the value of the time constant. C(a) and CVR were estimated using mathematical transformations of arterial pressure (ABP) and transcranial Doppler (TCD) cerebral blood flow velocity waveforms. Responses of the time constant to controlled changes in EtCO(2) were compared in 34 young volunteers. Hypercapnia shortened the time constant (0.22 s [0.17, 0.26] vs. 0.16 s [0.13, 0.20]; p = 0.000001), while hypocapnia lengthened the time constant (0.22 s [0.17, 0.26] vs. 0.23 s [0.19, 0.32]; p < 0.0032). The time constant was negatively correlated with changes in EtCO(2) (R(partial) = -0.68, p < 0.000001). This was associated with a decrease in CVR when EtCO(2) increased (R(partial) = -0.80, p < 0.000001) and C(a) remained independent of changes in EtCO(2). C(a) was negatively correlated with mean ABP (R(partial) = -0.68, p < 0.000001). In summary, the time constant shortens with increasing EtCO(2). Its potential role in cerebrovascular investigations needs further studies.

Cerebrovascular time constant: dependence on cerebral perfusion pressure and end-tidal carbon dioxide concentration

OBJECTIVE

The cerebrovascular time constant (τ) describes the time to establish a change in cerebral blood volume after a step transient in arterial blood pressure (ABP). We studied the relationship between τ, ABP, intracranial pressure (ICP), and end-tidal carbon dioxide concentration (EtCO2).

METHOD

Recordings from 46 anaesthetized, paralysed and ventilated New Zealand rabbits were analysed retrospectively. ABP was directly monitored in the femoral artery, transcranial Doppler (TCD) cerebral blood flow velocity (CBFV) from the basilar artery, and ICP using an intraparenchymal sensor. In nine animals end-tidal CO2 (EtCO2) was monitored continuously. ABP was decreased with injection of trimetophan (n = 11) or haemorrhage (n = 6) and increased by boluses of dopamine (n = 11). ICP was increased by infusion of normal saline into the lumbar cerebrospinal fluid space (n = 9). Changes in cerebral compliance (C(a)) were estimated as a ratio of the pulse amplitude of the cerebral arterial blood volume (CBV) and the pulse amplitude of ABP. Changes in cerebrovascular resistance (CVR) were expressed as mean ABP or cerebral perfusion pressure (CPP) divided by mean CBFV. Time constant τ was calculated as the product of CVR and C(a).

RESULTS

The time constant changed inversely to the direction of the change in ABP (during arterial hypo- and hypertension) and CPP (during intracranial hypertension). C(a) increased with decreasing CPP, while CVR decreased. During a decrease in CPP, changes in C(a) exceeded changes in CVR. In contrast, during hypercapnia, the decrease in CVR was more pronounced than the increase in C(a), resulting in a decrease in τ.

CONCLUSION

Cerebrovascular time constant τ is modulated by ABP, ICP, and EtCO2.

Can postoperative cognitive dysfunction be avoided?

Postoperative cognitive dysfunction (POCD) refers to a postoperative decline in cognitive function compared with preoperative cognitive function. Diagnosis requires pre- and postoperative testing, the latter of which is usually performed both 7 days and 3 months postoperatively. Although several risk factors for POCD have been described, age is the only consistently reported risk factor. Postoperative cognitive dysfunction is often transient. It may last several months, and is associated with leaving the labor market prematurely and increased mortality. As the pathophysiology of POCD is still a matter of debate and is likely to be multifactorial, there are no widely accepted prophylactic and therapeutic interventions. In this article, we discuss POCD's definition, risk factors, long-term significance, and pathophysiology. We also present data on prophylactic interventions that have been investigated in clinical trials.

[Decompressive craniectomy in acute stroke - The different perspective]

Extensive space occupying strokes occur in about 1-10% of all ischaemic supratentorial infarctions. Both the high mortality and morbidity primarily result from secondary brain damage due to an accompanying brain edema. Therefore, the primary therapeutic target in patients with space occupying strokes is the control of the brain edema and the consecutively elevated intracranial pressure. If intracranial pressure cannot be controlled by conservative treatment methods, a decompressive craniectomy (DC) is a possible treatment option in selected patients to reduce intracranial pressure. In this review recommendations from the surgeon's perspective are given concerning the indication and timing of DC in patients with space occupying supra- and infratentorial cerebral infarctions.

Evaluation of a summary score of cognitive performance for use in trials in perioperative and critical care

BACKGROUND/AIMS

Cognitive dysfunction after medical treatment is increasingly being recognized. Studies on this topic require repeated cognitive testing within a short time. However, with repeated testing, practice effects must be expected. We quantified practice effects in a demographically corrected summary score of a neuropsychological test battery repeatedly administered to healthy elderly volunteers.

METHODS

The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Neuropsychological Assessment Battery (for which a demographically corrected summary score was developed), phonemic fluency tests, and trail-making tests were administered in healthy volunteers aged 65 years or older on days 0, 7, and 90. This battery allows calculation of a demographically adjusted continuous summary score.

RESULTS

Significant practice effects were observed in the CERAD total score and in the word list (learning and recall) subtest. Based on these volunteer data, we developed a threshold for diagnosis of postoperative cognitive dysfunction (POCD) with the CERAD total score.

CONCLUSION

Practice effects with repeated administration of neuropsychological tests must be accounted for in the interpretation of such tests. Ignoring practice effects may lead to an underestimation of POCD. The usefulness of the proposed demographically adjusted continuous score for cognitive function will have to be tested prospectively in patients.

Effect of age on intraoperative cerebrovascular autoregulation and near-infrared spectroscopy-derived cerebral oxygenation

BACKGROUND

Age is an important risk factor for perioperative cerebral complications such as stroke, postoperative cognitive dysfunction, and delirium. We explored the hypothesis that intraoperative cerebrovascular autoregulation is less efficient and brain tissue oxygenation lower in elderly patients, thus, increasing the vulnerability of elderly brains to systemic insults such as hypotension.

METHODS

We monitored intraoperative cerebral perfusion in 50 patients aged 18-40 and 77 patients >65 yr at two Swiss university hospitals. Mean arterial pressure (MAP) was measured continuously using a plethysmographic method. An index of cerebrovascular autoregulation (Mx) was calculated based on changes in transcranial Doppler flow velocity due to changes in MAP. Cerebral oxygenation was assessed by the tissue oxygenation index (TOI) using near-infrared spectroscopy. End-tidal CO₂, O₂, and sevoflurane concentrations and peripheral oxygen saturation were recorded continuously. Standardized anaesthesia was administered in all patients (thiopental, sevoflurane, fentanyl, atracurium).

RESULTS

Autoregulation was less efficient in patients aged >65 yr [by 0.10 (se 0.04; P=0.020)] in a multivariable linear regression analysis. This difference was not attributable to differences in MAP, end-tidal CO₂, or higher doses of sevoflurane. TOI was not significantly associated with age, sevoflurane dose, or Mx but increased with increasing flow velocity [by 0.09 (se 0.04; P=0.028)] and increasing MAP [by 0.11 (se 0.05; P=0.043)].

CONCLUSIONS

Our results do not support the hypothesis that older patients' brains are more vulnerable to systemic insults. The difference of autoregulation between the two groups was small and most likely clinically insignificant.

Changes in cerebral compartmental compliances during mild hypocapnia in patients with traumatic brain injury

The benefit of induced hyperventilation for intracranial pressure (ICP) control after severe traumatic brain injury (TBI) is controversial. In this study, we investigated the impact of early and sustained hyperventilation on compliances of the cerebral arteries and of the cerebrospinal (CSF) compartment during mild hyperventilation in severe TBI patients. We included 27 severe TBI patients (mean 39.5 ± 3.4 years, 6 women) in whom an increase in ventilation (20% increase in respiratory minute volume) was performed during 50 min as part of a standard clinical CO(2) reactivity test. Using a new mathematical model, cerebral arterial compliance (Ca) and CSF compartment compliance (Ci) were calculated based on the analysis of ICP, arterial blood pressure, and cerebral blood flow velocity waveforms. Hyperventilation initially induced a reduction in ICP (17.5 ± 6.6 vs. 13.9 ± 6.2 mmHg; p < 0.001), which correlated with an increase in Ci (r(2) = 0.213; p = 0.015). Concomitantly, the reduction in cerebral blood flow velocities (CBFV, 74.6 ± 27.0 vs. 62.9 ± 22.9 cm/sec; p < 0.001) marginally correlated with the reduction in Ca (r(2) = 0.209; p = 0.017). During sustained hyperventilation, ICP increased (13.9 ± 6.2 vs. 15.3 ± 6.4 mmHg; p < 0.001), which correlated with a reduction in Ci (r(2) = 0.297; p = 0.003), but no significant changes in Ca were found during that period. The early reduction in Ca persisted irrespective of the duration of hyperventilation, which may contribute to the lack of clinical benefit of hyperventilation after TBI. Further studies are needed to determine whether monitoring of arterial and CSF compartment compliances may detect and prevent an adverse ischemic event during hyperventilation.

Primary structure of the M subunit of the reaction center from Rhodopseudomonas sphaeroides

The reaction center is a membrane-bound bacteriochlorophyll-protein complex that mediates the primary photochemical events in the photosynthetic bacterium Rhodopseudomonas sphaeroides. The previously determined amino-terminal sequences of the three subunits of the reaction center protein were used to design synthetic mixed oligonucleotide probes for the structural genes encoding the subunits. One of these probes was used to isolate and clone a fragment of DNA from R. sphaeroides that contained the gene encoding the M subunit. The nucleotide sequence of this gene was determined by the dideoxy method. In addition, a number of tryptic and chymotryptic peptides from the M protein were isolated and subjected to sequence analysis, and the sequence of the carboxyl terminus was determined. Together with the amino-terminal sequence, the data establish the primary structure of the M protein. The distribution of hydrophobic residues in the amino acid sequence suggests the presence of five membrane-spanning segments. A significant homology was found between the amino acid sequence of the M subunit and a thylakoid membrane protein (M(r) 32,000) from spinach that has been implicated in herbicide and quinone binding.