EBQ:LINC Trial

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Complete Journal Club Article
Rubertsson, Sten et al. "Mechanical Chest Compressions and Simultaneous Defibrillation vs Conventional Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest (The LINC Randomized Trial)". JAMA. 2014. 311(1):53-61.
PubMed Full text PDF

Clinical Question

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.

Conclusion

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[1][2][3]
  • Two randomized studies of OHCA failed to find significant differences between manual and mechanical chest compressions using the Lucas device[4][5]
  • This study sought to emphasize the benefit of maximizing compression ratio and increasing compressions prior to defibrillation by first responders in cardiac arrest.[6][7]
  • 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[8]

Design

  • Multicenter randomized clinical trial of patients with OHCA
  • 2589 patients with OHCA between 2008-2013
  • 4 Swedish, 1 British, and 1 Dutch ambulance service

Inclusion Criteria

  • Age >18
  • Out of Hospital Cardiac Arrest

Exclusion Criteria

  • 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%

Initial rhythm:

V. fib 29% vs 30%
PEA20% vs 20%
Asystole 47% vs 46%

Time to ROSC from start of CPR: 17min vs 14min

Interventions

Mechanical CPR algorithm:

  1. Immediate manual CPR until the mechanical device was deployed
  2. Mechanical compressions for 3 min
  3. First defibrillation shock delivered without rhythm check at 90 sec
  4. Rhythm check after 3 min
  5. If shockable rhythm at 3 min then new 3 min cycle begun with shock at new 90 sec mark
  6. 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.

Outcome

Mechanical CPR vs Manual CPR

Primary Outcomes

4 hour survival: 23.6% vs 23.7% (P>.99%)

Secondary Outcomes

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

Adverse Outcomes

LUCAS group:

  • Airway bleeding: 1
  • Splenic rupture: 1
  • Pneumothorax: 1
  • Migration on Chest: 1

Thoracic vertebral fracture and flail chest not directly related to LUCAS

Manual group:

  • 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.

Funding

Institutional grants from Uppsala University and by Physio-Control/Jolife AB

Further Reading

References

  1. Steen S, Liao Q,Pierre L, Paskevicius A, Sjöberg T. Evaluation of LUCAS, a new device for automatic mechanical compression and active decompression resuscitation. Resuscitation. 2002;55(3):285-299.
  2. Rubertsson S, Karlsten R.Increased cortical cerebral blood flow with LUCAS; a new device for mechanical chest compressions compared to standard external compressions during experimental cardiopulmonary resuscitation. Resuscitation. 2005;65(3):357-363.
  3. Axelsson C, Karlsson T,Axelsson AB, Herlitz J. Mechanical active compression-decompression cardiopulmonary resuscitation (ACD-CPR) vs manual CPR according to pressure of end tidal carbon dioxide (P(ET)CO2) during CPR in out-of-hospital cardiac arrest (OHCA). Resuscitation. 2009;80(10):1099-1103.
  4. Axelsson C, Nestin J, Svensson L, Axelsson AB, Herlitz J. Clinical consequences of the introduction of mechanical chest compression in the EMS system for treatment of out-of-hospital cardiac arrest—a pilot study. Resuscitation. 2006;71(1):47-55.
  5. Smekal D, Johansson J, Huzevka T, Rubertsson S. A pilot study of mechanical chest compressions with the LUCAS device in cardiopulmonary resuscitation. Resuscitation. 2011;82(6):702-706.
  6. Cobb LA, Fahrenbruch CE, Walsh TR, et al. Influence of cardiopulmonary resuscitation prior to defibrillation in patients with out-of-hospital ventricular fibrillation. JAMA. 1999;281(13):1182- 1188.
  7. Wik L, Hansen TB, Fylling F, et al. Delaying defibrillation to give basic cardiopulmonary resuscitation to patients with out-of-hospital ventricular fibrillation: a randomized trial. JAMA. 2003;289(11):1389-1395.
  8. Olasveengen TM, et al.Quality of cardiopulmonary resuscitation before and during transport in out-of-hospital cardiac arrest. Resuscitation. 2008;76(2):185-190.