ECMO for COVID-19 patients in Europe and Israel

Since March 15th, 2020, 177 centres from Europe and Israel have joined the study, routinely reporting on the ECMO support they provide to COVID-19 patients. The mean annual number of cases treated with ECMO in the participating centres before the pandemic (2019) was 55. The number of COVID-19 patients has increased rapidly each week reaching 1531 treated patients as of September 14th. The greatest number of cases has been reported from France (n = 385), UK (n = 193), Germany (n = 176), Spain (n = 166), and Italy (n = 136) .The mean age of treated patients was 52.6 years (range 16–80), 79% were male. The ECMO configuration used was VV in 91% of cases, VA in 5% and other in 4%. The mean PaO2 before ECMO implantation was 65 mmHg. The mean duration of ECMO support thus far has been 18 days and the mean ICU length of stay of these patients was 33 days. As of the 14th September, overall 841 patients have been weaned from ECMO support, 601 died during ECMO support, 71 died after withdrawal of ECMO, 79 are still receiving ECMO support and for 10 patients status n.a. . Our preliminary data suggest that patients placed on ECMO with severe refractory respiratory or cardiac failure secondary to COVID-19 have a reasonable (55%) chance of survival. Further extensive data analysis is expected to provide invaluable information on the demographics, severity of illness, indications and different ECMO management strategies in these patients

An in vitro lung model to assess true shunt fraction by multiple inert gas elimination

The Multiple Inert Gas Elimination Technique, based on Micropore Membrane Inlet Mass Spectrometry, (MMIMS-MIGET) has been designed as a rapid and direct method to assess the full range of ventilation-to-perfusion (V/Q) ratios. MMIMS-MIGET distributions have not been assessed in an experimental setup with predefined V/Q-distributions. We aimed (I) to construct a novel in vitro lung model (IVLM) for the simulation of predefined V/Q distributions with five gas exchange compartments and (II) to correlate shunt fractions derived from MMIMS-MIGET with preset reference shunt values of the IVLM. Five hollow-fiber membrane oxygenators switched in parallel within a closed extracorporeal oxygenation circuit were ventilated with sweep gas (V) and perfused with human red cell suspension or saline (Q). Inert gas solution was infused into the perfusion circuit of the gas exchange assembly. Sweep gas flow (V) was kept constant and reference shunt fractions (IVLM-S) were established by bypassing one or more oxygenators with perfusate flow (Q). The derived shunt fractions (MM-S) were determined using MIGET by MMIMS from the retention data. Shunt derived by MMIMS-MIGET correlated well with preset reference shunt fractions. The in vitro lung model is a convenient system for the setup of predefined true shunt fractions in validation of MMIMS-MIGET

Bland-Altman analysis with saline as priming fluid.

<p>Bland-Altman analysis of MMIMS-MIGET based shunt fraction–with saline as priming fluid (MM-SNS) on predefined in vitro lung model shunt (IVLM-SNS). Bias ± precision (2 SD) was -0.04 00B1 0.12 with 95% limits of agreement (dashed) of -0.154 and 0.082.</p

Schematic of in vitro lung model setup.

<p>Schematic of in vitro lung model setup.</p

Linear regression analysis with saline as priming fluid.

<p>Linear regression analysis for MMIMS-MIGET shunt fraction–with saline as priming fluid (MM-SNS) on predefined in vitro lung model shunt (IVLM-SNS): MM-SNS = 0.91*IVLM-SNS +0.005 (r² = 0.99, P< 0.0001). Duplicate data from 0 to 0.8 model shunt fractions included. Solid line = linear regression; Dashed line = line of identity.</p

Linear regression analysis with blood as priming fluid.

<p>Linear regression analysis for MMIMS-MIGET based shunt fraction–with blood as priming fluid (MM-SRBC) on predefined in vitro lung model shunt (IVLM-SRBC): MM-SRBC = 0.87*IVLM-SRBC-0.02 (r2 = 0.96, P< 0.0001). Duplicate data from 0 to 0.8 model shunt fractions included. Solid line = linear regression; Dashed line = line of identity.</p

Neurophysiological and paraspinal oximetry monitoring to detect spinal cord ischemia in patients during and after descending aortic repair: An international multicenter explorative study

Background: During descending aortic repair, critically decreased blood flow to the myelum can result in ischemic spinal cord injury and transient or permanent paraplegia. Assessment of motor evoked potentials (MEPs) has been shown to be a valuable tool which allows to detect spinal cord ischemia (SCI) intraoperatively within a therapeutic window suitable to prevent progression to paraparesis or paraplegia. MEP monitoring is not feasible during postoperative care in the awakening patient. Therefore, ancillary techniques to monitor integrity of spinal cord function are needed to detect delayed spinal cord ischemia. Objective: The purpose of this study is to evaluate whether assessment of long loop reflexes (LLR; F-waves) and paraspinal muscle oximetry using Near-Infrared Spectroscopy (NIRS) are feasible and valid in detecting delayed SCI. Methods: We aim to include patients from three tertiary referral centers undergoing aortic repair with MEP monitoring in this study.F-wave measurements and paraspinal NIRS oximetry will be operated intra- and postoperatively. Measurement characteristics and feasibility will be assessed in the first 25 patients. Subsequently, a second cohort of 75 patients will be investigated to determine the sensitivity and specificity of F-waves and NIRS in detecting perioperative SCI. In this context for the MEP group SCI is defined intraoperatively as significant MEP changes and postoperatively as newly developed paraplegia. Conclusions: A clinical study design and protocol is proposed to assess if F-waves and/or NIRS-based paraspinal oximetry are feasible and valid in detecting and monitoring for occurrences of delayed SCI

Artificial Circulatory Setup.

<p>Artificial circulatory setup with two independent circuits filled with human packed red blood cells (haematocrit of 30%). A switching valve between the circuits enabled a step-change between highly oxygenated (circuit 1: purged with pure oxygen) and oxygen free blood (circuit 2: purged with nitrogen). Black arrows represent direction of blood flow. Adapting the settings of the rollerpumps and the heating-cooling device (heat exchanger) allowed blood-flow and temperature to be controlled. Via the O₂/N₂ blenders, oxygen content could be adapted at fixed sweep gas flow over the oxygenators. Measurement chamber contained 1.) ports for insertion of MFPF probes (Foxy-AL 300); 2.) a temperature probe and 3.) a sampling port for Clark-typed based (CTE) P_O2 analysis (ABL 700).</p