Pre-Hospital Randomized Assessment of a Mechanical Compression Device in Cardiac Arrest - PARAMEDIC

Description:

The current trial sought to investigate whether community use of automated defibrillation and chest compressions with the LUCAS device would be superior to manual cardiopulmonary resuscitation (CPR) in patients with unexpected out-of-hospital cardiac arrest (OHCA).

Hypothesis:

LUCAS-guided CPR would be superior compared with manual CPR for survival at 30 days in patients with OHCA.

Study Design

  • Randomized
  • Parallel

Patient Populations:

  • Trial vehicle was the first ambulance service vehicle on scene
  • Patient was in cardiac arrest outside of a hospital
  • Resuscitation was attempted
  • Patient was known or believed to be aged 18 years or older

    Number of enrollees: 4,471
    Duration of follow-up: 30 days
    Mean patient age: 71.3
    Percentage female: 37%

Exclusions:

  • Cardiac arrest caused by trauma
  • Known or clinically apparent pregnancy

Primary Endpoints:

  • Survival at 30 days

Secondary Endpoints:

  • Survived event (ROSC sustained until admission and transfer of care to medical staff at the receiving hospital)
  • Survival to 3 months
  • Survival to 12 months
  • Survival with favorable neurological outcome at 3 months

Drug/Procedures Used:

This was a randomized cluster trial where the ambulance service vehicles served as the unit of randomization. Individual ambulance vehicles were randomized in a 1:2 fashion to either LUCAS CPR or manual CPR, stratified by station and vehicle type. Individual patients were allocated to the LUCAS-2 or control (standard manual chest compression) group according to the first trial vehicle on scene.

The LUCAS-2 (Physio-Control Inc./Jolife AB, Lund, Sweden) device provides chest compressions between 40–53 mm in depth (according to patient size) at a rate of 102/minute and ensures full chest recoil between compressions, and an equal time in compression and decompression. In the LUCAS-2 group, staff initiated manual CPR and switched the device on. Patients in the control group received manual CPR aiming for a target compression depth of 50–60 mm, rate 100–120/minute, full recoil between compressions, and an equal time in compression and decompression in line with guidelines. Both groups received compression to ventilation ratio of 30:2 before intubation, and continuous compressions with asynchronous ventilation after intubation.

Concomitant Medications:

Post return of spontaneous circulation (ROSC) care was provided based on local hospital protocols.

Principal Findings:

A total of 418 emergency vehicles were randomized, with 147 clusters receiving LUCAS-2 and 271 manual CPR. This included 4,471 patients, of which 1,652 were allocated to LUCAS-2 (of which 985 actually received LUCAS-2 compressions) and 2,819 to manual CPR. Baseline characteristics were fairly similar between the two arms. The presumed etiology was cardiac in 85% of all patients and respiratory in 8%. The majority of OHCAs happened at home (82%), with bystander CPR administered in 43%. The initial rhythm was ventricular tachycardia (VT)/ventricular fibrillation (VF) in 23%, pulseless electrical activity in 25%, and asystole in nearly 50%. Less than a quarter of patients had successful ROSC before arriving at the hospital.

The primary endpoint of survival at 30 days was similar between the LUCAS-guided CPR and manual CPR arms (6% vs. 7%, odds ratio 0.91, 95% confidence interval 0.71-1.17). ROSC (32% vs. 31%), survival to 3 months (6% vs. 6%), and survival with favorable neurological outcome (5% vs. 6%) were all similar between the two arms (p > 0.05 for all). Results were similar on adjusting for compliance with LUCAS-2 use. On subgroup analysis, 30-day survival was lower with the LUCAS-2 device in patients with VT/VF as the initial rhythm (18% vs. 24%, p < 0.05). Other subgroup analyses (cardiac vs. other arrest; bystander CPR vs. none) showed similar results.

Seven clinical adverse events were reported in the LUCAS-2 group (three events of chest bruising, two of chest laceration, and two of blood in mouth). No serious adverse events were reported. Fifteen device incidents occurred during operational use (four incidents in which alarms sounded, seven in which the device stopped working, and four other device incidents).

Interpretation:

The results of the PARAMEDIC trial indicate that survival at 30 days following OHCA in a community-based all-comers trial is abysmally low (~6%), with no improvements with the use of the automated LUCAS-2 device over manual CPR. Studies demonstrate that manual chest compressions during CPR result in only 20-30% of normal blood flow and are difficult to perform for a long period of time. Following small pilot studies, there has been recent interest in mechanical chest compressions with the LUCAS device. The current trial, in conjunction with two other recent trials, indicates that the LUCAS device does not, however, confer a clinical benefit.

References:

Perkins GD, Lall R, Quinn T, et al., on behalf of the PARAMEDIC Trial Collaborators. Mechanical versus manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised controlled trial. Lancet 2014;Nov 16:[Epub ahead of print].

Presented Dr. Gavin Perkins at the American Heart Association Scientific Sessions, Chicago, IL, November 16, 2014.

Clinical Topics: Arrhythmias and Clinical EP, EP Basic Science, SCD/Ventricular Arrhythmias

Keywords: Ambulances, Intubation, Tachycardia, Ventricular, Follow-Up Studies, Out-of-Hospital Cardiac Arrest, Ventricular Fibrillation, Cardiopulmonary Resuscitation, Electric Countershock, Confidence Intervals, Lacerations, AHA Annual Scientific Sessions


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