Impact of pulse pressure on clinical outcome in extracorporeal cardiopulmonary resuscitation (eCPR) patients

Background

Hemodynamic response after successful extracorporeal cardiopulmonary resuscitation (eCPR) is very heterogeneous. Pulse pressure (PP) as an easy to access surrogate parameter and correlate for myocardial damage or recovery from it, might be a valuable tool to estimate the outcome of these patients.

Purpose

To investigate the predictive value of the surrogate parameter PP in eCPR patients.

Methods

We report retrospective data of a single-centre registry of eCPR patients, treated at our Interdisciplinary Medical Intensive Care Unit between 01/2017 and 01/2020. The association between PP of the first 10 days after eCPR and hospital survival was investigated. Moreover, patients were divided into three groups according to their PP (low (0–9 mmHg), mid (10–29 mmHg) and high (≥30 mmHg)) at each time point.

Results

143 patients (age 63 years, 74.1% male, 40% OHCA, average low flow time 49 min) were analysed. Overall hospital survival rate was 28%. A low PP both early after eCPR (after 1, 3, 6 and 12 hours) and in the further course after day 1 to day 8 was associated with reduced hospital survival. At each time point (1 hour to day 5) the classification of patients into a low, mid and high PP group was able to categorize the patients for a low (5–20%), moderate (20–40%) and high (50–70%) survival rate. A multivariable analysis showed that the mean PP of the first 24 hours was an independent predictor for survival (p=0.008, figure 1).

Conclusion

In this analysis, PP occurred to be a valuable parameter to estimate survival and maybe support clinical decision making in the further course of patients after eCPR.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Survival of eCPR patients by mean 24hPP

[Freiburg Cardiac Arrest Receiving Team (CART) : Interdisciplinary solution for the acute management of non-traumatic out-of-hospital cardiac arrest]

Standard procedures and guidelines provide specific instructions for basic and advanced cardiac life support. Recommendations for the admission of patients from preclinical into clinical structures after successful cardiopulmonary resuscitation (CPR) are available, but only a few are detailed. In the presence of ST-elevation myocardial infarction after return of spontaneous circulation (ROSC), coronary angiography must be performed as soon as possible. However, acute management and consecutive diagnostic procedures after hospital admission are up to the doctor on duty, who can rely on standard internal hospital procedures at best. Despite the enormous progress and new findings in intensive care and emergency medicine, intra-hospital mortality, as well as long-term survival, after CPR remains low and depends on a wide variety of influencing factors. To optimize in-hospital acute care of successfully resuscitated patients, an interdisciplinary admission team, a so-called cardiac arrest receiving team (CART), has been implemented at the University Hospital of Freiburg, Germany. The aim of the CART is to provide primary care to resuscitated patients as quickly and in as standardized a manner as possible with predefined diagnostic and therapeutic pathways by a team with special expertise in the field of CPR and post-resuscitation management. Accordingly, clear criteria for procedures and the location of primary care (e.g. emergency room vs. cardiac catheter laboratory), the composition of the CART and concrete treatment measures were defined.

Superior neurologic recovery after 15 minutes of normothermic cardiac arrest using an extracorporeal life support system for optimized blood pressure and flow

OBJECTIVE

Sudden cardiac arrest is one of the leading causes of death. Conventional CPR techniques after cardiac arrest provide circulation with reduced and varying blood flow and pressure. We hypothesize that using pressure- and flow-controlled reperfusion of the whole body improves neurological recovery and survival after 15 min of normothermic cardiac arrest.

METHODS

Pigs were randomized in two experimental groups and exposed to 15 min of ventricular fibrillation (VF). After this period, the animals in the control group received conventional CPR with open chest compression (n=6), while circulation in the treatment group (n=6) was established with an extracorporeal life support system (ECLS) to control blood pressure and flow. Follow-up included the assessment of neurological recovery and magnetic resonance imaging (MRI) for up to 7 days.

RESULTS

Five of the six animals in the control group died, one animal was resuscitated successfully. In the treatment group, 1/6 could not be separated from ECLS. Five out of the six pigs survived and were transferred to the animal facility. One animal was unable to walk and had to be sacrificed 30 hours after ECLS. The remaining 4 animals of the treatment group and the surviving pig from the control group showed complete neurological recovery. Brain MRI revealed no pathological changes.

CONCLUSION

We were able to demonstrate a significant improvement in survival after 15 minutes of normothermic cardiac arrest. These results support our hypothesis that using an ECLS for pressure- and flow-controlled circulation after circulatory arrest is superior to conventional CPR.

Prolonged cardiac arrest and resuscitation by extracorporeal life support: favourable outcome without preceding anticoagulation in an experimental setting

State-of-the-art cardiopulmonary resuscitation (CPR) restores circulation with inconsistent blood-flow and pressure. Extracorporeal life support (ECLS) following CPR opens the opportunity for "controlled reperfusion". In animal experiments investigating CPR with ECLS, systemic anticoagulation before induced cardiac arrest is normal, but a major point of dispute, since preliminary heparinization in patients undergoing unwitnessed cardiac arrest is impossible. In this study, we investigated options for ECLS after an experimental 15 minutes normothermic cardiac arrest, without preceding anticoagulation, in pigs. Neurological recovery was assessed by a scoring system, electroencephalography and brain magnetic resonance imaging. Additionally, brain histology was performed on day seven after cardiac arrest. We demonstrated that preliminary heparin administration was not necessary for survival or neurological recovery in this setting. Heparin flushing of the cannulae seemed sufficient to avoid thrombus formation. These findings may ease the way to using ECLS in patients with sudden cardiac arrest.