Comparison between propofol and total inhalational anaesthesia on cardiovascular outcomes following on-pump cardiac surgery in higher-risk patients: a randomised controlled pilot and feasibility study

OBJECTIVES

Myocardial revascularisation and cardiopulmonary bypass (CPB) can cause ischaemia-reperfusion injury, leading to myocardial and other end-organ damage. Volatile anaesthetics protect the myocardium in experimental studies. However, there is uncertainty about whether this translates into clinical benefits because of the coadministration of propofol and its detrimental effects, restricting myocardial protective processes.

METHODS

In this single-blinded, parallel-group randomised controlled feasibility trial, higher-risk patients undergoing elective coronary artery bypass graft (CABG) surgery with an additive European System for Cardiac Operative Risk Evaluation ≥5 were randomised to receive either propofol or total inhalational anaesthesia as single agents for maintenance of anaesthesia. The primary outcome was the feasibility of recruiting and randomising 50 patients across two cardiac surgical centres, and secondary outcomes included the feasibility of collecting the planned perioperative data, clinically relevant outcomes and assessments of effective patient identification, screening and recruitment.

RESULTS

All 50 patients were recruited within 11 months in two centres, allowing for a 13-month hiatus in recruitment due to the COVID-19 pandemic. Overall, 50/108 (46%) of eligible patients were recruited. One patient withdrew before surgery and one patient did not undergo surgery. All but one completed in-hospital and 30-day follow-up.

CONCLUSIONS

It is feasible to recruit and randomise higher-risk patients undergoing CABG surgery to a study comparing total inhalational and propofol anaesthesia in a timely manner and with high acceptance and completion rates.

TRIAL REGISTRATION NUMBER

NCT04039854.

How to Personalize General Anesthesia-A Prospective Theoretical Approach to Conformational Changes of Halogenated Anesthetics in Fire Smoke Poisoning

Smoke intoxication is a central event in mass burn incidents, and toxic smoke acts at different levels of the body, blocking breathing and oxygenation. The majority of these patients require early induction of anesthesia to preserve vital functions. We studied the influence of hemoglobin (HMG) and myoglobin (MGB) blockade by hydrochloric acid (HCl) in an interaction model with gaseous anesthetics using molecular docking techniques. In the next part of the study, molecular dynamics (MD) simulations were performed on the top-scoring ligand-receptor complexes to investigate the stability of the ligand-receptor complexes and the interactions between ligands and receptors in more detail. Through docking analysis, we observed that hemoglobin creates more stable complexes with anesthetic gases than myoglobin. Intoxication with gaseous hydrochloric acid produces conformational and binding energy changes of anesthetic gases to the substrate (both the pathway and the binding site), the most significant being recorded in the case of desflurane and sevoflurane, while for halothane and isoflurane, they remain unchanged. According to our theoretical model, the selection of anesthetic agents for patients affected by fire smoke containing hydrochloric acid is critical to ensure optimal anesthetic effects. In this regard, our model suggests that halothane and isoflurane are the most suitable choices for predicting the anesthetic effects in such patients when compared to sevoflurane and desflurane.

Volatile Anaesthesia versus Total Intravenous Anaesthesia for Cardiac Surgery—A Narrative Review

Recent research has contested the previously accepted paradigm that volatile anaesthetics improve outcomes in cardiac surgery patients when compared to intravenous anaesthesia. In this review we summarise the mechanisms of myocardial ischaemia/reperfusion injury and cardioprotection in cardiac surgery. In addition, we make a comprehensive analysis of evidence comparing outcomes in patients undergoing cardiac surgery under volatile or intravenous anaesthesia, in terms of mortality and morbidity (cardiac, neurological, renal, pulmonary).

Inhalational or total intravenous anesthetic for cardiac surgery: does the debate even exist?

PURPOSE OF REVIEW

Perioperative myocardial injury related to cardiac surgery is associated with organ dysfunction and increased mortality. Volatile anesthetics (VA) have been used during cardiac surgery for decades because of their direct and indirect preconditioning and protection against ischemia-reperfusion injury. The current review provides a summary of the latest literature comparing pharmacological preconditioning and the potential benefits of using VA versus total intravenous anesthesia (TIVA) for general anesthesia to improve outcomes after cardiac surgery.

RECENT FINDINGS

Recent literature reports lower mortality and better outcomes when VA is used alone or in combination with remote ischemic preconditioning compared with groups receiving TIVA. However, inconsistent research findings over the years have led to continued debate regarding the anesthetic technique considered more favorable for cardiac surgery.

SUMMARY

Research findings regarding the use of volatile anesthetic versus TIVA for better outcomes after cardiac surgery are inconsistent. Variability in timing, duration, dosing, and type of VA as well as surgical and patient-related factors may have influenced these results. Therefore, either technique can reasonably be adopted depending on provider and institutional preference and used safely in patients undergoing cardiac surgery.

Inhaled Anesthetics: Environmental Role, Occupational Risk, and Clinical Use

Inhaled anesthetics have been in clinical use for over 150 years and are still commonly used in daily practice. The initial view of inhaled anesthetics as indispensable for general anesthesia has evolved during the years and, currently, its general use has even been questioned. Beyond the traditional risks inherent to any drug in use, inhaled anesthetics are exceptionally strong greenhouse gases (GHG) and may pose considerable occupational risks. This emphasizes the importance of evaluating and considering its use in clinical practices. Despite the overwhelming scientific evidence of worsening climate changes, control measures are very slowly implemented. Therefore, it is the responsibility of all society sectors, including the health sector to maximally decrease GHG emissions where possible. Within the field of anesthesia, the potential to reduce GHG emissions can be briefly summarized as follows: Stop or avoid the use of nitrous oxide (N2O) and desflurane, consider the use of total intravenous or local-regional anesthesia, invest in the development of new technologies to minimize volatile anesthetics consumption, scavenging systems, and destruction of waste gas. The improved and sustained awareness of the medical community regarding the climate impact of inhaled anesthetics is mandatory to bring change in the current practice.

Sevoflurane prevents vulnerable plaque disruption in apolipoprotein E-knockout mice by increasing collagen deposition and inhibiting inflammation

BACKGROUND

Sevoflurane may reduce the occurrence of major adverse cardiovascular events (MACCEs) in surgical patients, although the mechanisms are poorly understood. We hypothesised that sevoflurane stabilises atherosclerotic plaques by inhibiting inflammation and enhancing prolyl-4-hydroxylase α1 (P4Hα1), the rate-limiting subunit for the P4H enzyme essential for collagen synthesis.

METHODS

We established a vulnerable arterial plaque model in apolipoprotein E-knockout mice (ApoE^-/-) fed a high-fat diet that underwent daily restraint/noise stress, with/without a single prior exposure to sevoflurane for 6 h (1-3%; n=30 per group). In vitro, smooth muscle cells (SMCs) were incubated with tumour necrosis factor-alpha in the presence/absence of sevoflurane. Immunohistochemistry, immunoblots, and mRNA concentrations were used to quantify the effect of sevoflurane on plaque formation, expression of inflammatory cytokines, P4Hα1, and collagen subtypes in atherosclerotic plaques or isolated SMCs.

RESULTS

In ApoE^-/- mice, inhalation of sevoflurane 1-3% for 6 h reduced the aortic plaque size by 8-29% in a dose-dependent manner, compared with control mice that underwent restraint stress alone (P<0.05); this was associated with reduced macrophage infiltration and lower lipid concentrations in plaques. Sevoflurane reduced gene transcription and protein expression levels of pro-inflammatory cytokines (≥69-75%; P<0.05) and matrix metalloproteinases (≥39-65%; P<0.05) at both gene transcription and protein levels, compared with controls. Sevoflurane dose dependently increased Types I and III collagen deposition through enhanced protein expression of P4Hα1, both in vivo and in vitro (0.7-3.3-fold change; P<0.05).

CONCLUSIONS

Sevoflurane dose dependently promotes plaque stabilisation and decreases the incidence of plaque disruption in ApoE^-/- mice by increasing collagen deposition and inhibiting inflammation. These mechanisms may contribute to sevoflurane reducing MACCE.

Volatile Anesthetics versus Propofol for Cardiac Surgery with Cardiopulmonary Bypass

Background

The aim of this systematic review and meta-analysis was to assess the effect of anesthesia maintenance with volatile agents compared with propofol on both short- and long-term mortality (primary outcomes) and major clinical events in adults undergoing cardiac surgery with cardiopulmonary bypass.

Methods

Randomized clinical trials on the effects of current volatile anesthetics versus propofol in adults undergoing cardiac surgery with cardiopulmonary bypass were searched (1965 to September 30, 2019) in PubMed, the Cochrane Library, and article reference lists. A random effect model on standardized mean difference for continuous outcomes and odds ratio for dichotomous outcomes were used to meta-analyze data.

Results

In total, 37 full-text articles (42 studies, 8,197 participants) were included. The class of volatile anesthetics compared with propofol was associated with lower 1-yr mortality (5.5 vs. 6.8%; odds ratio, 0.76 [95% CI, 0.60 to 0.96]; P = 0.023), myocardial infarction (odds ratio, 0.60 [95% CI, 0.39 to 0.92]; P = 0.023), cardiac troponin release (standardized mean difference, −0.39 [95% CI, −0.59 to −0.18], P = 0.0002), need for inotropic medications (odds ratio, 0.40 [95% CI, 0.24 to 0.67]; P = 0.0004), extubation time (standardized mean difference, −0.35 [95% CI, −0.68 to −0.02]; P = 0.038), and with higher cardiac index/output (standardized mean difference, 0.70 [95% CI, 0.37 to 1.04]; P &lt; 0.0001). The class of volatile anesthetics was not associated with changes in short-term mortality (1.63 vs. 1.65%; odds ratio, 1.04 [95% CI, 0.73 to 1.49]; P = 0.820) and acute kidney injury (odds ratio, 1.25 [95% CI, 0.77 to 2.03]; P = 0.358).

Conclusions

In adults undergoing cardiac surgery with cardiopulmonary bypass, the class of volatile anesthetics was superior to propofol with regard to long-term mortality, as well as to many secondary outcomes indicating myocardial protection.

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

The Impact of Anesthetic Regimen on Outcomes in Adult Cardiac Surgery: A Narrative Review

Despite improvements in surgical techniques and perioperative care, cardiac surgery still is burdened by relatively high mortality and frequent major postoperative complications, including myocardial dysfunction, pulmonary complications, neurologic injury, and acute kidney injury. Although the surgeon's skills and volume and patient- and procedure-related risk factors play a major role in the success of cardiac surgery, there is growing evidence that also optimizing perioperative care may improve outcomes significantly. The present review focuses on the aspects of perioperative care that are strictly related to the anesthesia regimen, with special reference to volatile anesthetics and neuraxial anesthesia, whose effect on outcome in adult cardiac surgery has been investigated extensively.

Development of a prototype anti-pollution filter for volatile anesthetics

INTRODUCTION

The use of volatile agents during cardiopulmonary bypass allows a "single drug anesthesia" and is associated with reduced peak postoperative troponin levels. Connecting the exhaust systems to the oxygenator's gas outlet port is mandatory and allows to prevent operating room (but not atmospheric) pollution by volatile agents. The aim of this study was to create a prototype filter for volatile agents and to test its adsorption efficacy during an ex-vivo simulated conventional cardiopulmonary bypass test.

METHODS

We carried out bench tests to conceive a prototype filter that could prevent room and environment pollution without damaging membrane oxygenators. We performed the tests at the Engineering Center for Circulatory Assistance Laboratory, Dante Pazzanese Institute of Cardiology, São Paulo, Brazil. Bench tests included simulation of integral adsorption tests, filter dimensions and design, flow versus pressure curve, sizing, and tightness.

RESULTS

Calgon AT 410 was the best kind of activated charcoal granules for adsorption of sevoflurane, isoflurane, and desflurane. Filter dimension tests showed that a chamber of 30-cm width over 10-cm diameter filled with 200 g of the Calgon AT410 granules was the minimum required to fully adsorb sevoflurane for 90 min. Adsorption tests showed that the prototype filter fully adsorbed isoflurane in 100 ± 2.3 min, sevoflurane in 95 ± 3.4 min, and desflurane in 95 ± 4.3 min.

CONCLUSION

The new version of our prototype filter adsorbed most of the volatile anesthetics agents during an ex-vivo simulated conventional cardiopulmonary bypass test.

Anaesthetic management in endovascular total aortic arch repair via needle-based in situ fenestration: a case series of 14 patients

Objective

Endovascular total aortic arch repair (ETAAR) via needle-based in situ fenestration (ISF) is a major challenge for anaesthesiologists because of haemodynamic instability and the risk of cerebral hypoxia. We herein summarise our experience with anaesthetic management of patients who underwent this procedure.

Methods

Fourteen patients who underwent ETAAR via ISF for arch pathologies involving the major supra-arch branches were included. Regional cerebral oxygen saturation was measured to monitor cerebral perfusion. Partial extracorporeal circulation (EC) support from the right common femoral vein to the right axillary artery was introduced to provide cerebral perfusion.

Results

During ISF, vessel rupture occurred in three patients and ventricular fibrillation occurred in one patient. The regional cerebral oxygen saturation significantly decreased during the potential risk period for cerebral ischaemia. Establishment of EC effectively prevented cerebral ischaemia.

Conclusions

During ETAAR, the risks of haemodynamic instability caused by the procedure and vessel rupture during ISF need to be overcome. Partial EC ensured good cerebral protection in our study, and regional cerebral oxygen saturation monitoring may help to reduce the rate of desaturation.

Postoperative Cardiac Troponin I Thresholds Associated With 1-Year Cardiac Mortality After Adult Cardiac Surgery: An Attempt to Link Risk Stratification With Management Stratification in an Observational Study

OBJECTIVES

Cardiac troponin (cTn) concentrations are measured routinely in some centers after cardiac surgery as part of risk stratification, but there are no data on how increased cTn concentrations could change patients' management. The aim of this study was to estimate relevant cTnI thresholds and identify potential interventions (additional monitoring/therapeutic interventions) that could be part of management changes of patients with cTnI greater than relevant thresholds.

DESIGN

Retrospective, single-center, observational study.

SETTING

Bichat-Claude Bernard Hospital, Paris, France, between January 1, 2009, and December 31, 2012.

PARTICIPANTS

Consecutive adult patients undergoing cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

cTnI was measured on the 20th postoperative hour. Causes of death and possible interventions were determined by analysis of individual medical records. cTnI thresholds for 1-year cardiac mortality with a specificity >80% were calculated. For this study, 3,228 procedures were analyzed; 129 deaths occurred (4%), 83 of which (2.6%) were cardiac deaths. Threshold cTnI values were 4.2 µg/L for coronary artery bypass grafting (95% confidence interval [CI] 3.9-4.5) and 10.7 µg/L for non-coronary artery bypass grafting (95% CI 10.0-11.3). In multivariable analysis, the EuroSCORE II (odds ratio 1.1 [95% CI 1.06-1.13]; p < 0.001) and cTnI concentrations greater than the thresholds (odds ratio 5.62 [95% CI 3.37-9.37]; p < 0.001) were associated with significantly increased risk of death. The additive and absolute Net Reclassification Index were 0.288% and 14.1%, respectively, for a logistic model including cTnI and EuroSCORE II (area under the curve C-index 0.82 [95% CI 0.77-0.87]) compared with a model including only EuroSCORE II (area under the curve C-index 0.80 [95% CI 0.75-0.84]). Fifty-three of the 83 patients who experienced cardiac death (64%) had a cTnI concentration greater than the threshold, and an intervention was deemed possible in 47 of those 53 (89%) (mostly patients with mild postoperative cardiac dysfunction). For noncardiac deaths, 28% of patients had a cTnI concentration greater than the threshold and no interventions were deemed possible.

CONCLUSIONS

In an attempt to evolve from risk to management stratification, this study's results identified a subgroup of patients with mild cardiac dysfunction and a cTnI concentration greater than the threshold who could be the target for interventions in future validation studies concerning changes in patient management.

Pre-cardiopulmonary bypass administration of dexmedetomidine decreases cardiac troponin I level following cardiac surgery with sevoflurane postconditioning

Objective

This study was performed to determine the effect of dexmedetomidine (DEX) administration on myocardial damage in cardiac surgery with sevoflurane postconditioning.

Methods

We retrospectively examined all cardiac valve replacement surgeries from 1 April 2016 to 30 April 2017. Eligible patients were divided into two groups based on whether DEX was infused. DEX infusion was permitted only between intubation and the beginning of cardiopulmonary bypass (CPB). Sevoflurane was inhaled via the standard postconditioning procedure starting at aortic declamping. The cardiac troponin I (cTnI) level was measured at different time points. The postoperative outcomes and complications were also analyzed.

Results

One hundred patients were included in the study (DEX group, n = 53; non-DEX group, n = 47). Increased cTnI levels were significantly correlated with the New York Heart Association classification, CPB time, and DEX use. DEX use and the CPB time were potential independent factors contributing to changes in the cTnI level. The cTnI level at 6, 12, and 24 hours postoperatively was remarkably lower in the DEX than non-DEX group by 1.14, 7.83, and 5.86 ng/mL, respectively.

Conclusions

DEX decreased the cTnI level after CPB when sevoflurane postconditioning was used, especially at 6, 12, and 24 hours postoperatively.

Identification of Candidate Genes and Pathways in Dexmedetomidine-Induced Cardioprotection in the Rat Heart by Bioinformatics Analysis

Dexmedetomidine (DEX), a highly selective alpha2 adrenergic receptor agonist, directly protects hearts against ischemia/reperfusion (I/R) injury. However, the detailed mechanism has not been fully elucidated. We studied differentially expressed mRNAs and miRNAs after DEX administration in rat hearts by comprehensive analysis. Additionally, bioinformatics analysis was applied to explore candidate genes and pathways that might play important roles in DEX-induced cardioprotection. The results of microarray analysis showed that 165 mRNAs and 6 miRNAs were differentially expressed after DEX administration. Through bioinformatics analysis using differentially expressed mRNAs, gene ontology (GO) terms including MAP kinase tyrosine/serine/threonine phosphatase activity and pathways including the p53 pathway were significantly enriched in the down-regulated mRNAs. Dusp1 and Atm were associated with the GO term of MAP kinase tyrosine/serine/threonine phosphatase activity and the p53 pathway, respectively. On the other hand, no significant pathway was found in the target mRNAs of deregulated miRNAs. The results indicated some possible key genes and pathways that seem to be of significance in DEX-induced cardioprotection, although miRNAs seem to be unlikely to contribute to cardioprotection induced by DEX.