An impedance threshold device did not improve carotid blood flow in a porcine model of prolonged cardiac arrest

Benedict Kjaergaard,Erika F Christensen,Sigridur O Magnusdottir,Søren Lundbye-Christensen,Hans O Holdgaard

doi:10.1186/s12967-020-02264-5

Benedict Kjaergaard, Erika F Christensen + Show 3 more

Open Access

https://doi.org/10.1186/s12967-020-02264-5

Copy DOI

Abstract

BackgroundAn impedance threshold device (ITD) was developed to increase venous return to the heart and therefore increase cardiac output and organ blood flow during cardiopulmonary rescue (CPR). Basic CPR aims to maintain coronary and cerebral blood flow at the minimum level necessary for survival. The present study compared the effects of an ITD on cerebral blood flow assessed as blood flow in both carotid arteries to the blood flow of a control group during prolonged CPR.MethodsFourteen anaesthetized pigs were monitored during 60 min of CPR after induced ventricular fibrillation. The primary outcome was blood flow in both carotid arteries, and the secondary outcomes were blood pressure, acid–base parameters, plasma potassium, and plasma lactate. The pigs were randomized to mechanical compressions and ventilation with an ITD added to the ventilation or to a control group treated only with mechanical compressions and ventilation. The time course for the parameters was tested using analysis of variance.ResultsThe cumulative carotid blood flow in the ITD group decreased from 64 to 42 ml/min, and it decreased from 69 to 51 ml/min in the control group during 60 min of CPR. The difference was not significant. The secondary outcome measures were also not significantly different.ConclusionsThis study did not show any beneficial effect of an ITD on carotid blood flow.

Highlights

An impedance threshold device (ITD) was developed to increase venous return to the heart and there‐ fore increase cardiac output and organ blood flow during cardiopulmonary rescue (CPR)
Kjaergaard et al J Transl Med (2020) 18:83 randomized study with ITD or sham ITD in patients with out-of-hospital cardiac arrest, there was no difference in survival to hospital discharge [9]
Another study showed a benefit of an ITD but only in cases where the quality of CPR was good, and the opposite result was found if the patient did not receive an acceptable quality of CPR [10]

Summary

Introduction

An impedance threshold device (ITD) was developed to increase venous return to the heart and there‐ fore increase cardiac output and organ blood flow during cardiopulmonary rescue (CPR). It is often necessary to perform prolonged cardiopulmonary resuscitation (CPR) on patients with cardiac arrest (CA) during transportation to a hospital. Under these conditions, it is helpful to use mechanical chest compression devices, such as LUCAS and Autopulse [1, 2]. It is of clinical interest to know if an ITD improves brain circulation during prolonged CPR when DC conversions and medications do not result in return of spontaneous circulation (ROSC) Under these conditions, another method with extracorporeal life support may be a bridge to diagnosis, treatment and survival provided that the circulation to the brain was sufficient until ECC was established [13, 14]

Methods

Results

Conclusion