Does an algorithm combining mechanical chest compression and defibrillation provide a short term survival benefit in out-of-hospital cardiac arrest (OHCA) when compared to a traditional algorithm of manual chest compressions and defibrillation.
There was no 4-hour survival benefit in the mechanical vs. manual CPR algorithm.
Background & Major Points
- The LUCAS mechanical CPR device has previously been shown to provide enhanced cerebral blood flow and higher end tidal CO2 although no survival outcomes have been demonstrated from the device's use
- Two randomized studies of OHCA failed to find significant differences between manual and mechanical chest compressions using the Lucas device
- This study sought to emphasize the benefit of maximizing compression ratio and increasing compressions prior to defibrillation by first responders in cardiac arrest.
- However, like all prior studies using mechanical compression devices, no significant benefit has been demonstrated clinically although minimal harm and at the very least the two modes of CPR appear equivalent. Other benefits although not clinically significant may be to prehospital providers ability to perform CPR during transport
- Multicenter randomized clinical trial of patients with OHCA
- 2589 patients with OHCA between 2008-2013
- 4 Swedish, 1 British, and 1 Dutch ambulance service
- Age >18
- Out of Hospital Cardiac Arrest
- Traumatic Cardiac Arrest (including hanging)
- Age < 18 years old
- Known pregnancy
- Body size too large or small to fit the LUCAS compression device
- Defibrillation before the LUCAS arrived on scene
- Patients with cardiac arrest witnessed by the EMS crew and received return of spontaneous circulation (ROSC) after immediate defibrilation
Baseline Patient Characteristics
Mechanical vs Manual CPR
age: 69 vs 69.1
male: 67% vs 66%
heart disease: 65% vs 63%
pulmonary disease: 64% vs 69%
respiratory arrest: 59% vs 47%
witnessed arrest: 66% vs 65%
bystander CPR: 57% vs 55%
- V. fib 29% vs 30%
- PEA20% vs 20%
- Asystole 47% vs 46%
Time to ROSC from start of CPR: 17min vs 14min
Mechanical CPR algorithm:
- Immediate manual CPR until the mechanical device was deployed
- Mechanical compressions for 3 min
- First defibrillation shock delivered without rhythm check at 90 sec
- Rhythm check after 3 min
- If shockable rhythm at 3 min then new 3 min cycle begun with shock at new 90 sec mark
- if no shockable rhythm then 3 min of mechanical CPR with no defibrillation until next 3min rhythm check
Manual CPR algorithm
- In accordance with the 2005 European Resuscitation Council guidelines
Paramedics were trained at initiation of trial and ever 6 months in the mechanical algorithm
Post Resuscitation care
- Patients were treated with hypothermia (32C-34C) for 24hours regardless of initial ECG rhythm.
Mechanical CPR vs Manual CPR
4 hour survival: 23.6% vs 23.7% (P>.99%)
Arrival at emergency department with pulse: 28.2% vs 27.7% Survival to discharge from ICU:
- CPC score 1-2 on hospital discharge: 8.3% vs. 7.8%
- 6month survivals with CPC score 1-2: 8.5% v 7.6%
Chest compression fraction: 0.84 vs 0.78
- Airway bleeding: 1
- Splenic rupture: 1
- Pneumothorax: 1
- Migration on Chest: 1
Thoracic vertebral fracture and flail chest not directly related to LUCAS
- Flail chest: 2
- Abdominal Aortic aneurysm: 1
- Pneumothorax: 1
Criticisms & Further Discussion
- The study is more about comparing a unique algorithm that prioritizes chest compressions over defibrilation and just so happens to use a mechanical compression device since the LUCAS arm had a different resuscitation protocol with extra shock delivery at 90 seconds.
- The study is industry sponsored by Physio-Control and Jolife AB with the lead author receiving consulting fees from Physio-Control
- Inference regarding the use of mechanical vs manual compressions is limited since a different resuscitation algorithm was used for the two arms
- The study suggests equivalence in the two means of resuscitation (mechanical with modified CPR and traditional CPR algorithms) and no increase in adverse events
- The LUCAS group did not seem to offer a manpower advantage or speed advantage since arrival times in the hospital were faster with the standard CPR group.
- When focusing on patient centered outcomes, no differences were found in survival outcomes.
Institutional grants from Uppsala University and by Physio-Control/Jolife AB
- EMLit of Note - Man vs Machine
- ALiEM - Mechanical CPR and LINC trial
- ScanCrit - CPR Man vs Machine: 1-1
- Emergency medicine Ireland - The LINC Trial
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