Dexmedetomidine for adult cardiac surgery: a systematic review, meta-analysis and trial sequential analysis

The effects of dexmedetomidine in adults undergoing cardiac surgery are inconsistent. We conducted a systematic review and meta-analysis to analyse the effects of peri-operative dexmedetomidine in adults undergoing cardiac surgery. We searched MEDLINE via Pubmed, EMBASE, Scopus and Cochrane for relevant randomised controlled trials between 1 January 1990 and 1 March 2022. We used the Joanna Briggs Institute methodology checklist to assess study quality and the GRADE approach to certainty of evidence. We assessed the sensitivity of results to false data. We used random-effects meta-analyses to analyse the primary outcomes: durations of intensive care and tracheal intubation. We included 48 trials of 6273 participants. Dexmedetomidine reduced the mean (95%CI) duration of intensive care by 5.0 (2.2-7.7) h, p = 0.001, and tracheal intubation by 1.6 (0.6-2.7) h, p = 0.003. The relative risk (95%CI) for postoperative delirium was 0.58 (0.43-0.78), p = 0.001; 0.76 (0.61-0.95) for atrial fibrillation, p = 0.015; and 0.49 (0.25-0.97) for short-term mortality, p = 0.041. Bradycardia and hypotension were not significantly affected. Trial sequential analysis was consistent with the primary meta-analysis. Adjustments for possible false data reduced the mean (95%CI) reduction in duration of intensive care and tracheal intubation by dexmedetomidine to 3.6 (1.8-5.4) h and 0.8 (0.2-1.4) h, respectively. Binary adjustment for methodological quality at a Joanna Briggs Institute score threshold of 10 did not alter the results significantly. In summary, peri-operative dexmedetomidine reduced the durations of intensive care and tracheal intubation and the incidence of short-term mortality after adult cardiac surgery. The reductions in intensive care stay and tracheal intubation may or may not be considered clinically useful, particularly after adjustment for possible false data.

Extracorporeal membrane oxygenation in peripartum cardiomyopathy: A review of the ELSO Registry

AIMS

Data on the use of extracorporeal membrane oxygenation (ECMO) for cardiogenic shock in peripartum cardiomyopathy (PPCM) is limited. We queried the Extracorporeal Life Support Organization (ELSO) Registry for PPCM patients treated with ECMO in order to characterize demographic and clinical features, complications, survival, and variables associated with mortality.

METHODS AND RESULTS

This was a retrospective review of patients voluntarily entered into the ELSO Registry. De-identified data was collected on patients with a diagnosis of PPCM based on ICD-9/ICD-10 coding who received ECMO between 2007 and 2019. Collected data included demographics, ECMO mode, cannulation strategies, pre-ECMO ventilator, biochemical, and hemodynamic parameters, run duration, complications, and survival to wean off ECMO and hospital discharge. Our primary outcome measure was survival to discharge. In the final analysis, 88 veno-arterial (VA) ECMO patients were included. Overall, 72% of patients were weaned off ECMO, including 10% who were weaned to ventricular assist device or heart transplantation, and 64% survived to hospital discharge. Extracorporeal cardiopulmonary resuscitation (ECPR) was performed in 11% of patients with 60% survival. Factors associated with decreased survival included neurologic complications (p = 0.03), specifically central nervous system hemorrhage (p = 0.01).

CONCLUSION

Our review is the largest to date of PPCM patients supported with VA ECMO for cardiogenic shock. ECMO and ECPR are valuable forms of short-term mechanical circulatory support with acceptable mortality profiles for PPCM patients who remain refractory to aggressive medical management. Complications should be meticulously avoided, especially neurologic complications.

Successful Use of ECMO in Adults with Life-threatening Infections

Two cases of critically ill patients who received extracorporeal membrane oxygenation (ECMO) using different forms of circuitry and for different indications are presented. Both patients had life-threatening infections with septic shock and were not able to be supported by conventional means. The first patient had staphylococcal septicaemia and received venoarterial ECMO for circulatory failure. The second patient had psittacosis and received venovenous ECMO for respiratory failure. We discuss the expanding indications for this technology and the role it has to play in adult intensive care.

Bloodless Intensive Care: A Case Series and Review of Jehovah's Witnesses in ICU

The objective of this study was to assess the outcome of Jehovah's Witness (JW) patients admitted to a major Australasian ICU and to review the literature regarding the management of critically ill Jehovah's Witness patients.

All Jehovah's Witness patients admitted to the ICU between January 1999 and September 2003 were identified from a prospective database. Their ICU mortality, APACHE II scores, APACHE II risk of death and ICU length of stay were compared to the general ICU population. Twenty-one (0.24%) out of 8869 patients (excluding re-admissions) admitted to the ICU over this period were Jehovah's Witness patients. Their mean APACHE II score was 14.1 (±7.0), the mean APACHE II risk of death was 21.2% (±16.6), and the mean nadir haemoglobin (Hb) was 80.2 g/l (±36.4). Four out of 21 Jehovah's Witness patients died in ICU compared to 782 out of 8848 non- Jehovah's Witness patients (19.0% vs 8.8%, P=0.10, chi square). The median ICU length of stay in both groups was two days (P=0.64, Wilcoxon rank sum). The lowest Hb recorded in a survivor was 23 g/l.

Jehovah's Witness patients appear to be an uncommon patient population in a major Australasian ICU but are not over-represented when compared with their prevalence in the community. Despite similar severity of illness scores and predicted mortality to those in the general ICU population, there was a trend towards higher mortality in Jehovah's Witness patients.

ECMO in acute and chronic adult respiratory failure: recent trends and future directions

Extracorporeal membrane oxygenation (ECMO) can be used to preserve or enhance systemic oxygen delivery in patients with refractory cardiac or respiratory failure. Although widely accepted as a standard of care for many indications in children and for adult cardiogenic shock, ECMO for adult respiratory failure is more controversial. This controversy arose over thirty years ago after the disappointing results of the first flawed, randomized study and is fueled by a group of non-ECMO clinicians who repeatedly criticize the methodology of more recent studies which show probable benefit. In spite of this, there is probably now more evidence to support the use of ECMO in refractory acute respiratory distress syndrome than for any other form of rescue therapy. The purpose of this review is to update clinicians regarding trends in ECMO research over the last 12 months and speculate on how the clinical use of ECMO and associated technology will evolve.

Evaluation of echocardiography indices of systolic function: a comparative study using pressure-volume loops in patients undergoing coronary artery bypass surgery

Transoesophageal echocardiography measures of systolic left ventricular function obtained during coronary artery bypass surgery are heavily influenced by alterations in loading conditions. No validation of these measurements against load independent indices obtained by pressure-volume loop analysis has been undertaken in humans. Ten patients undergoing coronary artery bypass surgery underwent simultaneous transoesophageal echocardiography and pressure-volume loop analysis of cardiac function at different loading conditions (reduced preload, increased afterload and atrial pacing). Fractional area change, afterload corrected fractional area change, and lateral basal wall peak systolic myocardial velocity, along with dP/dt, were compared to the preload recruitable stroke work relationship. There were no significant differences between the echocardiography measures when compared to the preload recruitable stroke work relationship; however, dP/dt varied significantly across loading conditions (p<0.001). Transoesophageal echocardiography adequately assesses systolic function across loading conditions commonly seen during coronary artery bypass surgery.