Introduction: Studies comparing manual active compression-decompression CPR (ACD-CPR) to manual CPR have shown similar survival rates. Recently a new mechanical ACD-CPR device (LUCAS2AD, Jolife AB/Physio-Control, Lund, Sweden) was compared to the standard LUCAS2 device in pigs, documenting improved hemodynamics. In this first clinical study on mechanical ACD-CPR we hypothesized that it would produce better hemodynamic variables than the standard LUCAS2 device (ClinicalTrials.gov NCT02479152).
Methods: The trial is a prospective block-randomized unblinded study of out-of-hospital cardiac arrest patients >18 years old with anterior-posterior (AP) chest diameter 185-280mm, treated by the physician manned vehicle in Oslo. Inclusion criteria: simultaneous minimum 5 minutes of LUCAS2/LUCAS2AD chest compressions, intubated and side stream pCO2 measurements. Exclusion criteria: traumatic arrest, pregnancy, imprisonment and previous chest surgery. LIFEPAK 15 data was exported via CodeStat 10 (both PhysioControl, Redmond, WA, USA) to Excel and analyzed by automatic algorithms in MatLab. The primary end-point pETCO2was collected as the averaged top readings from two consecutive 3-12 seconds long ventilations every 30-second period. Generalized linear mixed model (GLMM) was used.
Results: Of 221 patients enrolled, 211 were analyzed (excluded n=10, (denied consent n=6, various n=4)). Eligible patients for per protocol final inclusion were 133 (LUCAS2 n=64, LUCAS2AD n=69). Intention-to-treat group had AP-diameter (<185mm n=53, >280mm n=2), too short observation period and technical issues (n=23). So far 90% of patient data is analyzed. Averaged pETCO2: LUCAS2 32.5mmHg (n=61) and LUCAS2AD 31.0mmHg (n=65). GLMM did not reveal significant differences between the devices at any time-point (difference for LUCAS2AD: -1.2mmHg, standard error 2.40, CI -5.94 to 3.54, p=0.62). Calculation with ITT group did not change the result (difference for LUCAS2AD -1.05mmHg, standard error 2.57, CI -6.1 to 4.0, p=0.68). Overall survival was 6.3% (14) patients, all CPC 1 and 44.7% (99) patients had ROSC on arrival to hospital.
Conclusion: Preliminary analysis of pETCO2 data in the LUCAS2AD trial did not find statistical differences between the two groups.