Benzodiazepine-Free Cardiac Anesthesia for Reduction of Postoperative Delirium (B-Free): A Protocol for a Multi-centre Randomized Cluster Crossover Trial

Delirium is common after cardiac surgery and is associated with adverse outcomes. Administration of benzodiazepines before and after cardiac surgery is associated with delirium; guidelines recommend minimizing their use. Benzodiazepine administration during cardiac surgery remains common because of its recognized benefits. The Benzodiazepine-Free Cardiac Anesthesia for Reduction of Postoperative Delirium (B-Free) trial is a randomized cluster crossover trial evaluating whether an institutional policy of restricting intraoperative benzodiazepine administration (ie, ≥ 90% of patients do not receive benzodiazepines during cardiac surgery), as compared with a policy of liberal intraoperative benzodiazepine administration (ie, ≥ 90% of patients receive ≥ 0.03 mg/kg midazolam equivalent), reduces delirium. Hospitals performing ≥ 250 cardiac surgeries a year are included if their cardiac anesthesia group agrees to apply both benzodiazepine policies per their randomization, and patients are assessed for postoperative delirium every 12 hours in routine clinical care. Hospitals apply the restricted or liberal benzodiazepine policy during 12 to 18 crossover periods of 4 weeks each. Randomization for all periods takes place in advance of site startup; sites are notified of their allocated policy during the last week of each crossover period. Policies are applied to all patients undergoing cardiac surgery during the trial period. The primary outcome is the incidence of delirium at up to 72 hours after surgery. The B-Free trial will enroll ≥ 18,000 patients undergoing cardiac surgery at 20 hospitals across North America. Delirium is common after cardiac surgery, and benzodiazepines are associated with the occurrence of delirium. The B-Free trial will determine whether an institutional policy restricting the administration of benzodiazepines during cardiac surgery reduces the incidence of delirium after cardiac surgery. Clinicaltrials.gov registration number: NCT03928236 (First registered April 26, 2019).

Intracranial pressure monitoring in the perioperative period of patients with acute liver failure undergoing orthotopic liver transplantation

Acute liver failure (ALF) may result in severe neurological complications caused by cerebral edema and elevated intracranial pressure (ICP). Multiple pathogenic mechanisms explain the elevated ICP, and newer hypotheses have been described. While invasive ICP monitoring (ICPM) may have a role in ALF management, these patients are typically coagulopathic and at risk for intracranial hemorrhage. ICPM is the subject of much debate, and significant heterogeneity exists in clinical practice regarding its use. Contemporary ICPM techniques and coagulopathy reversal strategies may be associated with a lower risk of hemorrhage; however, most of the evidence is limited by its retrospective nature and relatively small sample size.

Intraoperative transesophageal echocardiography following mitral valve repair: a systematic review

OBJECTIVE

We aimed to examine the recent evidence and search for novel assessments on intraoperative TEE following mitral valve repair that can impact short and long-term outcomes.

METHODS

The Ovid MEDLINE, PubMed, and EMBASE databases were searched from January 1, 2008, until January 27, 2021, for studies on patients with severe Mitral Valve Regurgitation (MR) undergoing Mitral Valve (MV) repair surgery with intraoperative Transesophageal Echocardiography (TEE) performed after the repair. Additional searches were conducted using Google search engine, Web of Science, and Cochrane Library.

RESULTS

After reviewing 302 records, 8 retrospective and 22 prospective studies were included (n = 30). Due to clinical and methodological diversity, these studies are noncomparable and data were not amenable to quantitative synthesis.

CONCLUSION

Although technological advances allowed the objective assessment of geometric and dynamic alterations of the MV, the impact of the use of these technologies on short- or long-term outcomes was not studied. There is uncertainty and conflicting evidence on the ideal method and metrics to evaluate MV patency post-repair. Few isolated studies validated methods to assess coaptation surface and LV function post-repair.

Intraoperative management of liver transplant in a patient with an undiagnosed ventricular septal defect: A case report

BACKGROUND

The intraoperative management of patients undergoing orthotopic liver transplantation (OLT) frequently encounters hemodynamic instability after reperfusion of the new liver graft. The resulting post-reperfusion syndrome is characterized by an increase in pulmonary vascular resistance and decrease in systemic vascular resistance. In the presence of a left to right intracardiac shunt, this hemodynamic perturbance can lead to shunt reversal followed by hypoxemia and embolization of air and debris into the systemic circulatory system.

CASE SUMMARY

A 43 years-old male with end-stage liver disease due to primary sclerosing cholangitis complicated by portal hypertension and hepatocellular carcinoma presented for an OLT. A bedside transthoracic echocardiography (TTE) was performed immediately before the procedure and unexpectedly identified a ventricular septal defect (VSD). The patient and the surgical team agreed to proceed with the surgery as it was a time critical donation after circulatory organ death. We developed an intraoperative plan to optimize pulmonary and systemic pressures using vasoactive support, optimized mechanical ventilation, and used transesophageal echocardiography (TEE) for intraoperative monitoring. During reperfusion, considerable turbulent flows with air were noted in the right ventricle, but no air was visualized in the left ventricle. Color flow Doppler showed no reversal flow in the VSD. At the end of the procedure, the patient was extubated in the operating room without complication and was transferred to the transplant unit for recovery.

CONCLUSION

Our case highlights the importance of echocardiography in the perioperative assessment of patients undergoing liver transplantation. The TTE findings obtained immediately before the procedure and the real-time use of intraoperative TEE to modify our management during the critical phases of the transplant resulted in continuity of care and a good surgical outcome for this patient.