Magnesium sulphate to prevent perioperative atrial fibrillation in cardiac surgery: a randomized clinical trial : A protocol description of the PeriOperative Magnesium Infusion to Prevent Atrial fibrillation Evaluated (POMPAE) trial.

BACKGROUND: Postoperative atrial fibrillation (POAF) is a common and potentially serious complication post cardiac surgery. Hypomagnesaemia is common after cardiac surgery and recent evidence indicates that supplementation of magnesium may prevent POAF. We aim to investigate the effectiveness of continuous intravenous magnesium sulphate administration in the perioperative period to prevent POAF as compared to placebo. METHODS: The (POMPAE) trial is a phase 2, single-center, double-blinded randomized superiority clinical study. It aims to assess the impact of perioperative continuous intravenous magnesium administration on the occurrence of cardiac surgery-related POAF. A total of 530 patients will be included. Eligible patients will be randomized in 1:1 ratio to the intervention or placebo group with stratification based on the presence of valvular surgery. The objective of the infusion is to maintain ionized magnesium levels between 1.5 and 2.0 mmol/L. DISCUSSION: The primary outcome measure is the incidence of de novo POAF within the first 7 days following surgery, with censoring at hospital discharge. This trial may generate crucial evidence for the prevention of POAF and reduce clinical adverse events in patients following cardiac surgery. TRIAL REGISTRATION: The POMPAE trial was registered at ClinicalTrials.gov under the following identifier NTC05669417, https://clinicaltrials.gov/ct2/show/NCT05669417 . Registered on December 30, 2022. PROTOCOL VERSION: Version 3.3, dated 13-01-2023.

Withdrawing intra-aortic balloon pump support paradoxically improves microvascular flow.

INTRODUCTION: The Intra-Aortic Balloon Pump (IABP) is frequently used to mechanically support the heart. There is evidence that IABP improves microvascular flow during cardiogenic shock but its influence on the human microcirculation in patients deemed ready for discontinuing IABP support has not yet been studied. Therefore we used sidestream dark field imaging (SDF) to test our hypothesis that human microcirculation remains unaltered with or without IABP support in patients clinically ready for discontinuation of mechanical support. METHODS: We studied 15 ICU patients on IABP therapy. Measurements were performed after the clinical decision was made to remove the balloon catheter. We recorded global hemodynamic parameters and performed venous oximetry during maximal IABP support (1:1) and 10 minutes after temporarily stopping the IABP therapy. At both time points, we also recorded video clips of the sublingual microcirculation. From these we determined indices of microvascular perfusion including perfused vessel density (PVD) and microvascular flow index (MFI). RESULTS: Ceasing IABP support lowered mean arterial pressure (74 ± 8 to 71 ± 10 mmHg; P = 0.048) and increased diastolic pressure (43 ± 10 to 53 ± 9 mmHg; P = 0.0002). However, at the level of the microcirculation we found an increase of PVD of small vessels <20 µm (5.47 ± 1.76 to 6.63 ± 1.90; P = 0.0039). PVD for vessels >20 µm and MFI for both small and large vessels were unaltered. During the procedure global oxygenation parameters (ScvO2/SvO2) remained unchanged. CONCLUSIONS: In patients deemed ready for discontinuing IABP support according to current practice, SDF imaging showed an increase of microcirculatory flow of small vessels after ceasing IABP therapy. This observation may indicate that IABP impairs microvascular perfusion in recovered patients, although this warrants confirmation.

Imaging the human microcirculation during cardiopulmonary resuscitation in a hypothermic victim of submersion trauma.

The microcirculation is essential for delivery of oxygen and nutrients to tissue. However, the human microvascular response to cardiopulmonary resuscitation (CPR) is unknown. We report on the first use of sidestream dark field imaging to assess the human microcirculation during CPR with a mechanical chest compression/decompression device (mCPR). mCPR was able to provide microvascular perfusion. Capillary flow persisted even during brief mCPR interruption. However, indices of microvascular perfusion were low and improved vastly after return of spontaneous circulation. Microvascular perfusion was relatively independent from blood pressure. The microcirculation may be a useful monitor for determining the adequacy of CPR.