Remimazolam for anesthesia and sedation in cardiac surgery and for cardiac patients undergoing non-cardiac surgery: a systematic-narrative hybrid review.

INTRODUCTION: Remimazolam, an ultra-short-acting benzodiazepine recognized and approved as an anesthetic and sedative in multiple countries, offers a distinctive pharmacokinetic profile, boasting advantages such as rapid onset, short action duration, and rapid recovery. These attributes may contribute to enhanced hemodynamic stability and a diminished risk of respiratory depression compared to other sedatives. EVIDENCE ACQUISITION: We conducted the first comprehensive systematically structured narrative review to evaluate the role and potential application of remimazolam in cardiac surgery. Twenty-one studies published from 2021 to 2023 delved into remimazolam's application in open cardiac surgery, cardiac catheterization or electrophysiology laboratories, and high-risk cardiovascular patients undergoing non-cardiac surgery. EVIDENCE SYNTHESIS: Overall, remimazolam usage was apparently linked to potentially superior hemodynamic stability compared to other hypnotic drugs. However, findings regarding the reduction in postoperative delirium incidence with remimazolam and the doses of remimazolam for anesthesia induction and maintenance were inconsistent across the studies. CONCLUSIONS: Though remimazolam has demonstrated potential safety, efficacy, and ease-of-use for both anesthesia induction and maintenance in cardiac surgery patients and high-risk cardiovascular patients undergoing non-cardiac surgery, further research is imperative to delve into specific patient subgroups (e.g., the elderly or emergent procedures) so as to ascertain optimal dose ranges to suit diverse clinical scenarios.

Association of Impedance Aggregometry-Measured Platelet Aggregation With Thromboembolic Events in Patients Who Undergo Carotid Endarterectomy: A Pilot Study.

OBJECTIVES: The aim of the current study was to assess the relationship among thrombin receptor activator peptide 6 (TRAP test), adenosine-5'-diphosphate (ADP test), arachidonic acid (ASPI test), and stroke/transient ischemic attack (TIA), using the multiple electrode aggregometry (Multiplate) in patients undergoing carotid thromboendarterectomy (CEA). DESIGN: A retrospective study. SETTING: Vascular surgery operating rooms of a university hospital. PARTICIPANTS: One hundred thirty-one out of 474 patients undergoing CEA between November 2020 and October 2022. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A preoperative blood sample of all enrolled patients was analyzed using the Multiplate analyzer. Receiver operating characteristics curves, were generated to test the ability of TRAP, ADP, and ASPI in discriminating perioperative thromboembolic stroke/TIA. A logistic LASSO regression model was used to identify factors independently associated with stroke/TIA. Eight patients experienced a perioperative stroke/TIA. Although all the platelet functional assays showed excellent predictive performance, an ADP value exceeding 72 U showed the highest specificity (87%) and sensitivity (68%) in discriminating patients who had a perioperative thromboembolic stroke/TIA, with a negative predictive value of 99% and a positive predictive value of 15%. After LASSO regression, an ADP >72 U and the need for a shunt during CEA were the only 2 variables independently associated with perioperative stroke/TIA. CONCLUSION: Because the ADP test was independently associated with perioperative stroke/TIA, the assessment of platelet reactivity using Multiplate may offer potential utility in monitoring patients undergoing CEA.

Management of Microvascular Bleeding after On-Pump Cardiac Surgery in a Patient with Perioperative Diagnosis of Impairment of Platelet Responses to Adenosine Diphosphate: A Case Report and a Literature Review.

BACKGROUND: Impairment of platelet responses to adenosine diphosphate (ADP) is typified by mild to severe bleeding diathesis, easy bruising, excessive mucosal and post-operative bleeding. Patients lack full platelet activation and aggregation in response to ADP. Following research of the literature in Scopus, PubMed/MEDLINE, ScienceDirect, and the Cochrane Library, we report only 18 patients described to date with impaired platelet response to ADP, none of whom in the high bleeding-risk surgical setting or exploring potential therapeutic options. Data regarding population, putative genetic mutations, modes of inheritance, functional defects, and related clinical manifestations were retrieved from case series and case reports. CASE PRESENTATION: A 40-year-old woman was scheduled for on-pump cardiac surgery. Her past medical history included episodes of spontaneous mucocutaneous hemorrhages of the mild entity since childhood. Multiple electrode aggregometry (MEA, Multiplate® Roche Diagnostics, Rotkreuz, Switzerland) was used to evaluate platelet response to thrombin-activated peptide-6 (TRAP), arachidonic acid (ASPI), and ADP. An inadequate platelet aggregation induced using a high concentration of ADP with normal TRAP and ASPI tests was detected preoperatively. Therefore, intravenous desmopressin (DVVAP) 0.3 µg/kg body weight was administered to manage microvascular bleeding developed after weaning from cardiopulmonary bypass (CPB). CONCLUSIONS: Proper management of impaired platelet response to ADP requires a systematic assessment. The Multiplate analyzer is a valuable tool to promptly detect the disorder when a high clinical suspect is present and obtain insights during high bleeding-risk surgical procedures. DVVAP can be beneficial as first-line therapy in bleeding patients to improve platelet function.

Opioid Free Anesthesia in Thoracic Surgery: A Systematic Review and Meta Analysis.

Introduction: Recent studies showed that balanced opioid-free anesthesia is feasible and desirable in several surgical settings. However, in thoracic surgery, scientific evidence is still lacking. Thus, we conducted the first systematic review and meta-analysis of opioid-free anesthesia in this field. Methods: The primary outcome was the occurrence of any complication. Secondary outcomes were the length of hospital stay, recovery room length of stay, postoperative pain at 24 and 48 h, and morphine equivalent consumption at 48 h. Results: Out of 375 potentially relevant articles, 6 studies (1 randomized controlled trial and 5 observational cohort studies) counting a total of 904 patients were included. Opioid-free anesthesia compared to opioid-based anesthesia, was associated with a lower rate of any complication (74 of 175 [42%] vs. 200 of 294 [68%]; RR = 0.76; 95% CI, 0.65−0.89; p < 0.001; I2 = 0%), lower 48 h morphine equivalent consumption (MD −14.5 [−29.17/−0.22]; p = 0.05; I2 = 95%) and lower pain at 48 h (MD −1.95 [−3.6/0.3]; p = 0.02, I = 98%). Conclusions: Opioid-free anesthesia in thoracic surgery is associated with lower postoperative complications, and less opioid demand with better postoperative analgesia at 48 h compared to opioid-based anesthesia.

Mitral Valve Systolic Anterior Motion in Robotic Thoracic Surgery as the Cause of Unexplained Hemodynamic Shock: From a Case Report to Recommendations.

Robotic major lung resection for lung cancer carries a risk for intraoperative hemodynamic instability. Systolic anterior motion (SAM) of the mitral valve is a rare and often misrecognized cause of intraoperative hemodynamic instability. If not promptly recognized, SAM leads to a complicated perioperative course. Here, we report for the first time a case of a patient with SAM with a severe degree of left ventricular outflow obstruction (LVOTO) undergoing robotic lung lobectomy and its challenging intraoperative management. A 70-year-old man undergoing robotic left upper lobectomy developed immediately after the induction of general anesthesia hemodynamic instability due to SAM-related LVOTO. The diagnosis was possible, thanks to the use of transesophageal echocardiography (TEE). The treatment strategies applied were preload optimization without fluid overload, ultra-short-acting beta-blockers, and vasopressors. Peripheral nerve blockades were preferred over epidural analgesia to avoid vasodilatation. The patient reported a good quality of recovery and no pain the day after surgery. The management of patients with higher risk of SAM and LVOTO development during robotic thoracic surgery requires a dedicated and skilled team together with high-impact treatment strategies driven by TEE. Since current guidelines do not recommend the use of TEE, even for patients with higher cardiac risk undergoing noncardiac surgery, the present case report may stimulate interest in future recommendations.

Intravenous amino acid therapy for kidney protection in cardiac surgery a protocol for a multi-centre randomized blinded placebo controlled clinical trial. The PROTECTION trial.

BACKGROUND: Postoperative acute kidney injury (AKI) is frequent in cardiac surgery patients. Its pathophysiology is complex and involves decreased renal perfusion. Preliminary clinical evidence in critically ill patients shows that amino acids infusion increases renal blood flow and may decrease the incidence and severity of AKI. We designed a study to evaluate the effectiveness of perioperative continuous infusion of amino acids in decreasing AKI. METHODS: This is a phase III, multi-center, randomized, double-blind, placebo-controlled trial. Adults undergoing cardiac surgery with cardiopulmonary bypass (CPB) are included. Patients are randomly assigned to receive either continuous infusion of a balanced mixture of amino acids in a dose of 2 g/kg ideal body weight/day or placebo (balanced crystalloid solution) from the operating room up to start of renal replacement therapy (RRT), or ICU discharge, or 72 h after the first dose. The primary outcome is the incidence of AKI during hospital stay defined by KDIGO (Kidney Disease: Improving Global Outcomes). Secondary outcomes include the need for, and duration of, RRT, mechanical ventilation; ICU and hospital length of stay; all-cause mortality at ICU, hospital discharge, 30, 90, and 180 days after randomization; quality of life at 180 days. Data will be analyzed in 3500 patients on an intention-to-treat basis. DISCUSSION: The trial is ongoing and currently recruiting. It will be one of the first randomized controlled studies to assess the relationship between amino acids use and kidney injury in cardiac surgery. If our hypothesis is confirmed, this practice could reduce morbidity in the studied population. STUDY REGISTRATION: This trial was registered on ClinicalTrials.gov with the trial identification NCT03709264 in October 2018.

Association Between Type of Anaesthesia and Clinical Outcome in Patients Undergoing Endovascular Repair of Thoraco-Abdominal Aortic Aneurysms by Fenestrated and Branched Endografts.

OBJECTIVE: Although endovascular repair of thoraco-abdominal aortic aneurysm (TAAA) is the treatment of choice in the high risk population that is ineligible for an open surgical approach, little is known about the association between the type of anaesthesia and complications. This study compared the short term clinical outcomes of patients undergoing the visceral step of TAAA with fenestrated endograft aortic repair (FEVAR) and branched endograft aortic repair (BEVAR) under general anaesthesia (GA) with sedation with monitored care anaesthesia (MAC). METHODS: This single centre, retrospective, observational study recruited 124 consecutive patients undergoing elective F/BEVAR from 2014 - 2021. The primary endpoint was the short term complication rate according to the type of anaesthesia. Secondary endpoints included: need for inotropes or vasopressors for hypotension, time spent in the operating room, and admission to the intensive care unit. Propensity score matching was generated to account for the between group imbalance in the pre-operative covariables. RESULTS: After propensity score matching, 42 patients under GA were matched with 42 under MAC. The two groups showed no difference in cardiac and non-cardiac complications. Among the secondary outcomes, a higher number of patients in the GA group required inotropes or vasopressors compared with MAC (33% vs. 9%; p = .031). Although GA and MAC showed the same 30 day technical success (81% vs. 83%; p = .078), non-significant lower rates of major adverse events (10% vs. 12%; p = .72), one year re-intervention (14% vs. 21%; p = .39), and one year target vessel instability (10% vs. 21%; p = .39) were observed in the GA group. Overall, the in hospital mortality rate was 4%, with no difference between GA and MAC (2% vs. 5%; p = 1.0). CONCLUSION: The type of anaesthesia seemed to have no effect on procedure success, peri-operative morbidity, or mortality in patients undergoing F/BEVAR.

Less is more: We are administering too much protamine in cardiac surgery.

Context: Protamine is routinely administered to neutralize the anticlotting effects of heparin, traditionally at a dose of 1 mg for every 100 IU of heparin-a 1:1 ratio protamine sparing effects-but this is based more on experience and practice than literature evidence. The use of Hemostasis Management System (HMS) allows an individualized heparin and protamine titration. This usually results in a decreased protamine dose, thus limiting its side effects, including paradox anticoagulation. Aims: This study aims to assess how the use of HMS allows to reduction of protamine administration while restoring the basal activated clotting time (ACT) at the end of cardiac surgery. Settings and Design: A retrospective observational study in a tertiary care university hospital. Subjects and Methods: We analyzed data from 42 consecutive patients undergoing cardiopulmonary bypass (CPB) for cardiac surgery. For all patients HMS tests were performed before and after CPB, to determine how much heparin was needed to reach target ACT, and how much protamine was needed to reverse it. Results: At the end of cardiopulmonary bypass, 2.2 ± 0.5 mg/kg of protamine was sufficient to reverse heparin effects. The protamine-to-heparin ratio was 0.56:1 over heparin total dose (a 44% reduction) and 0.84:1 over heparin initial dose (a 16% reduction). Conclusion: A lower dose of protamine was sufficient to revert heparin effects after cardiopulmonary bypass. While larger studies are needed to confirm these findings and detect differences in clinically relevant outcomes, the administration of a lower protamine dose is endorsed by current guidelines and may help to avoid the detrimental effects of protamine overdose, including paradox bleeding.

Trigger and Target for Fibrinogen Supplementation Using Thromboelastometry (ROTEM) in Patients Undergoing Open Thoraco-Abdominal Aortic Aneurysm Repair.

OBJECTIVE: To determine the relationship between the value of fibrinogen assessed by the FIBTEM clot amplitude at 10 minutes (A10 FIBTEM) measured on admission to the intensive care unit (ICU) and the amount of drainage output at 24 hours, to investigate whether the A10 FIBTEM predicts severe bleeding (SB), and to define A10 FIBTEM thresholds to prevent (trigger) and treat (target) severe bleeding by fibrinogen supplementation. METHODS: In a single centre, retrospective observational study, 166 patients underwent elective open thoraco-abdominal aortic aneurysm (TAAA) repair between March 2016 and January 2019. Exclusion criteria were emergency, congenital, or acquired coagulopathy, or administration of P2Y12 inhibitor antiplatelet agents in the five days before surgery. All patients were managed intra-operatively and post-operatively according to a rotational thromboelastometry driven transfusion protocol. The principal endpoint was a composite outcome, which included bleeding, large volume transfusion, and re-operation. RESULTS: FIBTEM clot amplitude after 10 minutes measured on ICU admission and post-operative bleeding at 24 hours showed an inverse linear relationship (R2 = .03; p = .026). Performance of A10 FIBTEM in predicting SB evaluated by Receiving Operating Curve analysis showed an area under the curve of 0.63 (95% CI 0.56 - 0.70; p = .026) with a best cutoff of 9 mm. An A10 FIBTEM of 3 mm was the cutoff associated with a positive predictive value of 50%, while an A10 FIBTEM of 9 mm showed a negative predictive value of 92%. On multivariable analysis, an A10 FIBTEM ≤ 3 mm remained independently associated with SB. CONCLUSION: The present investigation shows for the first time in a population undergoing open TAAA repair that an A10 FIBTEM ≤ 3mm on ICU admission is associated with post-operative severe bleeding. Trigger and target values for fibrinogen supplementation, based on A10 FIBTEM, have been provided. The transferability and reliability of these cutoff values require further study.

Dynamic arterial elastance measured with pressure recording analytical method, and mean arterial pressure responsiveness in hypotensive preload dependent patients undergoing cardiac surgery: A prospective cohort study.

BACKGROUND: Organ perfusion is a factor of cardiac output and perfusion pressure. Recent evidence shows that dynamic arterial elastance is a reliable index of the interaction between the left ventricle and the arterial system and, in turn, of left ventricular mechanical efficiency. A practical approach to the assessment of dynamic arterial elastance at the bedside is the ratio between pulse pressure variation and stroke volume variation, which might predict the effect of a fluid challenge on the arterial pressure in patients undergoing cardiac surgery. OBJECTIVE: To evaluate the ability of dynamic arterial elastance, measured by the pressure recording analytical method (PRAM), to predict the response of mean arterial pressure (MAP) to a fluid challenge. DESIGN: Prospective observational study. SETTING: Cardiac surgery patients in a university hospital. PATIENTS: Preload-dependent (pulse pressure variation ≥13%), hypotensive (MAP ≤65 mmHg) patients, without right ventricular dysfunction, at the end of cardiac surgery. INTERVENTIONS: A 250 ml fluid challenge infused over 3 min. MAIN OUTCOME MEASURES: A receiver-operating characteristic curve was generated to test the ability of the baseline (before fluid challenge) dynamic arterial elastance (primary endpoint) and all other haemodynamic variables (secondary endpoint) to predict MAP responsiveness (≥10% increase in MAP) after a fluid challenge. RESULTS: Of 270 patients undergoing cardiac surgery, 97 (35.9%) were preload-dependent, hypotensive and received a fluid challenge. Of these 97 patients, 50 (51%) were MAP responders (≥10% increase in MAP) and 47 (48%) were MAP nonresponders (<10% increase in MAP). Baseline dynamic arterial elastance (mean ±â€ŠSD) had an area under the curve of 0.64 ±â€Š0.06 [95% confidence interval (CI), 0.53 to 0.73; P = 0.017]. A dynamic arterial elastance at least 1.07 with a grey zone ranging between 0.9 and 1.5 had 86% sensitivity (95% CI, 73 to 94) and 45% specificity (95% CI, 30 to 60) in predicting MAP increase. CONCLUSION: In a hypotensive preload-dependent cardiac surgery cohort without right ventricular dysfunction, dynamic arterial elastance measured by PRAM can predict pressure response for values greater than 1.5 or less than 0.9.

Esmolol in Cardiac Surgery: A Randomized Controlled Trial.

OBJECTIVE: To assess whether the administration of the ultra-short-acting ß-blocker esmolol in cardiac surgery could have a cardioprotective effect that translates into improved postoperative outcomes. DESIGN: Single-center, double-blinded, parallel-group randomized controlled trial. SETTING: A tertiary care referral center. PARTICIPANTS: Patients undergoing elective cardiac surgery with preoperative evidence of left ventricular end-diastolic diameter >60 mm and/or left ventricular ejection fraction <50%. INTERVENTIONS: Patients were assigned randomly to receive either esmolol (1 mg/kg as a bolus before aortic cross-clamping and 2 mg/kg mixed in the cardioplegia solution) or placebo in a 1:1 allocation ratio. MEASUREMENTS AND MAIN RESULTS: The primary composite endpoint of prolonged intensive care unit stay and/or in-hospital mortality occurred in 36/98 patients (36%) in the placebo group versus 27/102 patients (27%) in the esmolol group (p = 0.13). In the esmolol group, a reduction in the maximum inotropic score during the first 24 postoperative hours was observed (10 [interquartile range 5-15] v 7 [interquartile range 5-10.5]; p = 0.04), as well as a trend toward a reduction in postoperative low-cardiac-output syndrome (13/98 v 6/102; p = 0.08) and the rate of hospital admission at one year (26/95 v 16/96; p = 0.08). A trend toward an increase in the number of patients with ejection fraction ≥60% at hospital discharge also was observed (4/95 v 11/92; p = 0.06). CONCLUSIONS: In the present trial, esmolol as a cardioplegia adjuvant enhanced postoperative cardiac performance but did not reduce a composite endpoint of prolonged intensive care unit stay and/or mortality.

Differences in Biomarkers Pattern Between Severe Isolated Right and Left Ventricular Dysfunction After Cardiac Surgery.

OBJECTIVE: To find out if there are any differences in biomarkers between severe isolated right ventricular (RV) dysfunction and severe isolated left ventricular (LV) dysfunction after cardiac surgery using cardiopulmonary bypass. DESIGN: Observational study. SETTING: Teaching hospital. PARTICIPANTS: A total of 46 patients who had severe isolated RV or LV dysfunction after cardiac surgery. INTERVENTION: The authors collected perioperative clinical and biomarker data. MEASUREMENTS AND MAIN RESULTS: Severe isolated RV dysfunction patients (n = 20) had higher postoperative direct bilirubin (p = 0.030), total bilirubin (p = 0.044), glucose (p = 0.011), and international normalized ratio (INR) (p = 0.050) by repeated measure analysis of variance when compared with patients with severe isolated LV dysfunction (n = 26). The RV group also showed lower preoperative alanine transferase (19.3 ± 1.5 v 32.7 ± 4.2, p = 0.001), higher 4-hour INR (1.5 ± 0.3 v 1.4 ± 0.2, p = 0.008), and higher 48-hour INR (1.8 ± 0.4 v 1.4 ± 0.1, p < 0.001). None in the LV group died, whereas 4 patients in the RV group died (all of them had preoperative atrial fibrillation and underwent double valve replacement surgery). CONCLUSION: The authors observed biomarkers differences between severe isolated RV dysfunction and severe isolated RV dysfunction.

Editor's Choice - A Rotational Thromboelastometry Driven Transfusion Strategy Reduces Allogenic Blood Transfusion During Open Thoraco-abdominal Aortic Aneurysm Repair: A Propensity Score Matched Study.

OBJECTIVE: Open repair of thoraco-abdominal aortic aneurysm (TAAA) is a challenging procedure, associated with high rates of peri-operative bleeding and blood product transfusions. A large intra-operative volume transfusion has been associated with higher in hospital mortality and prolonged mechanical ventilation. A propensity score matched study was carried out to assess whether the introduction of a rotational thromboelastometry (ROTEM) based transfusion strategy reduces allogenic blood transfusion and affects morbidity in patients undergoing open TAAA repair. METHODS: All patients undergoing open TAAA repair at the San Raffaele Scientific Institute between 2009 and 2017 were included. Until 2016, a protocol based on estimated blood loss and conventional coagulation tests was used. After March 2016 a ROTEM guided transfusion protocol was developed and adopted. To account for selection bias, propensity score matching was performed. RESULTS: Five hundred and forty-seven consecutive patients were included. After propensity score matching, 77 patients in the ROTEM algorithm group were successfully matched with 77 patients in the standard algorithm group. Patients managed with ROTEM received fewer red blood cells units (3.5 [range 0-11] vs. 4 [range 0-17]; p = .026) and a lower volume of fresh frozen plasma (286 ± 496 vs. 2,050 ± 1,120; p < .001). In addition, fewer patients received fresh frozen plasma (35% vs. 97%; p < .001). Patients in the ROTEM group showed a significant decrease in the occurrence of pulmonary complications (44% vs. 83%; p = .01). Cost analysis showed a relevant reduction of per-patient expense after the introduction of ROTEM (€834 ± €577 vs. €1,285 ± €851; p < .001) CONCLUSION: A ROTEM guided transfusion strategy significantly limited the quantity of transfused blood products during open TAAA repair, improving clinical outcomes while reducing costs, allowing for better resource distribution in a setting where blood loss is relevant.