CONTROVERSIES IN EMS Why CPR First

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CONTROVERSIES IN EMSWhy CPR First?

• Jim Pointer, MD, FACEP
• Medical Director
• Alameda County EMS

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The Research
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The Cobb Study

• Design, Setting and Patients
• 639 VF patients
• Observational, prospectively defined
• Hospital survival rates before and after
  institution of 90 seconds of CPR prior to
  defibrillatory shock

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The Cobb Study (cont.)

• Results
• All patients
• Survival - shock first 24 (155/639)
• Survival - CPR first 30 (142/478) (p.04)
• Patients with response interval gt 4 minutes
• Survival - shock first 17 (56/321)
• Survival - CPR first 27 (60/220) (p.01)
• After adjusting patient factor differences
• CPR first - improved survival
• OR 1.42
• 95 CI 1.07 1.90
• P 0.2

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CPR Prior to DefibrillationWik, et al.

• Objective To study the effects of CPR before
  defibrillation in VF patients with response times
  lt or gt 5 minutes
• Design Blinded RCT of 200 out-of-hospital VF in
  Oslo between June 1998 May 2001

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CPR Prior to Defibrillation (cont.)Wik, et al.

• Groups
• Standard immediate defibrillation
• CPR first 3 minutes CPR prior to defibrillation
• (same if initial defibrillation unsuccessful)
• Outcome Measures
• Primary survival to hospital discharge
• Secondary ROSC on admission, 1-year survival,
  neuroloical outcome

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CPR Prior to Defibrillation

• Discussion
• No overall differences in survival for all
  patient group
• Significant differences in survival at discharge
  and at one-year for response time gt 5 minutes
• Agreement with Cobb
• Admission rate 46, and discharge rate 15
• Comparable to other Seattle studies

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Other Research

• Robinson et al.
• CPR first 2 minutes unwitnessed VF arrests
• ROSC 16, survival 4
• Defibbrillation first questioned
• Dog studies
• CPR first increases defibrillation success rates
  if limited to
• 3 7.5 minutes
• Niemann et al. (pig study)
• Survival improved with immediate defibrillation
  vs. with
• 5 minutes CPR first

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Conclusions

• Absolute delay before defibrillation is important
• Survival better with shorter response times
• Survival improved with CPR first if response
  times
• gt 5 minutes
• Prolonged VF increases probability of
  unsuccessful defibrillation (PEA or asystole)
• CPR may provide critical cardiac perfusion and
  metabolic state of myocytes ? ? more favorable
  response to defibrillation

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References

• Yakaitis RW, Ewy GA, Otto CW, et al. Influence
  of time and therapy on ventricular fibrillation
  in dogs. Critical Care Medicine. 1980
  8157-163.
• Niemann JT, Cairns CB, Sharma J, Lewis RJ.
  Treatment of prolonged ventricular fibrillation
  immediate countershock vs. high-dose epinephrine
  and CPR preceding countershock. Circulation.
  1992 85 281-287.
• Robinson JS, Davies MK, Johns BM, Edwards SN.
  Out-of-hospital cardiac arrests treated by the
  WestMidlands Ambulance Service over a two-year
  period. European Journal of Anesthesiology.
  1998 15 702-709

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References (cont.)

• Cobb LA, Fahrenbruch CF, Walsh TR, et al.
  Influence of cardiopulmonary resuscitation prior
  to defibrillation in patients with
  out-of-hospital ventricular fibrillation. JAMA.
  1999 281 1182-1188.
• Niemann JT, Cruz B, Garner D, Lewis RJ.
  Immediate countershock vs. cardiopulmonary
  resuscitation before countershock in a
  five-minute SMNE moidel of ventricular
  fibrillation arrest. Annals of Emergency
  Medicine. 2000 36 543-546.
• 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 1389-95.

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