Time to First Compression During Dispatcher-Assisted CPR is Not Associated with ROSC or Survival to Discharge

Lee M. Van Vleet MHS, NREMT-P • Michael Bachman MHS, NREMT-P • Michael Hubble PhD, NREMT-PWake County EMS, Raleigh, NC Wake County EMS, Raleigh, NC Western Carolina University, Cullowhee, NC

Table 1

• Retrospective data set from a single EMS system.

• Small sample size.

• Potentially confounding variables, such as CPR quality, timing of interventions, and hospital care were not available for inclusion in the logistic regression models.

Limitations

Within the limitations of our study design, we found that patients with a TTFC of ≤3 minutes were no more likely to achieve ROSC or survive to hospital discharge than patients with longer TTFC. Additional study is needed to determine ideal TTFC goals.

Conclusions

• Complete data were available for 609 cases.

• The mean patient age was 58.7 years and 61.5% of patients were male.

• A shockable rhythm was the initial rhythm in 21.7% of cases and 43.5% of arrests were witnessed.

• Mean TTFC was 4.1 (± 1.6) minutes and mean EMS response time 9.6 (± 4.1) minutes.

• Significant predictors of ROSC included age (OR=0.98) and shockable rhythm (OR=1.95), while significant predictors of survival to discharge included minority status (OR=1.96), witnessed arrest (OR=5.0), and shockable rhythm (OR=6.7). Compared to BVM only, patients receiving BIAD (OR=0.11) and ETI (OR=0.15) were less likely to survive to discharge. (Table 1)

• TTFC ≤ 3 minutes was not a significant predictor of ROSC or survival to discharge. (Table 1)

ResultsTo develop a model describing the impact of TTFC intervals of ≤3 minutes on ROSC and survival to hospital discharge.

Objective

Retrospective review of all non-traumatic 911 calls receiving CPR Pre-Arrival Instructions from December 2005 to February 2014.

• Audio recordings of each call were reviewed by an EMD QA officer to determine TTFC.

Other data abstracted from EMS reports:

• Initial ECG

• Final Airway

• Witnessed or not

• Patient demographics

• ROSC

• Survival to discharge

Data were modeled using logistic regression with p≤0.05 indicating significance.

Methods

Variable

Adjusted Odds RatioAdjusted Odds Ratio

VariableROSC Survival to

discharge

TTFC 1.06 (p = 0.81) 0.66 (p = 0.31)

Age 0.98 (p = 0.01) 0.98 (p = 0.09)

Gender1 0.86 (p = 0.51) 0.86 (p = 0.66)

Minority Status2 1.12 (p = 0.59) 1.96 (p = 0.04)

Witnessed Arrest3 0.90 (p = 0.63) 5.00 (p = 0.00)

Shockable Rhythm4 1.95 (p = 0.01) 6.77 (p = 0.00)

Final airway5

BIAD

ETI

0.58 (p = 0.14) 0.11 (p = 0.00)BIAD

ETI 0.68 (p = 0.31) 0.15 (p = 0.00)

EMS Response Time

1.03 (p = 0.23) 0.99 (p = 0.96)

1. Reference category = male.2. Reference category = Caucasian.3. Reference category = not witnessed.

4. Reference category = non-shockable.5. Reference category = BVM only.

Background• Rapid delivery of uninterrupted chest compressions is

a key component of successful resuscitation.

• Without bystander CPR, cardiac arrest survival decreases 7%-10% for every minute of delay until defibrillation.

• Dispatcher-assisted CPR increases the rate of bystander CPR and cardiac arrest survival.

• While there are uncontrollable barriers to the delivery of dispatcher-assisted CPR, the time to first compression (TTFC) remains a potentially modifiable component of the EMD-caller interaction. However, the effect of the TTFC on ROSC and survival to discharge is largely unknown.

Setting• Wake County, NC, is a

mixed urban/suburban county encompassing 831 square miles with a 2014 population of approximately 1 million residents.

• Approximately 90,000 EMS calls answered in 2014.

• Approximately 1,500 basic life support firefighter first responders with an estimated mean response time of 5 minutes.

• 225 ALS providers with a mean ambulance response time of 8.3 minutes.

• 87 credentialed emergency medical dispatchers utilizing MPDS protocol versions 11.2 through 12.2 across the study period.

•Raleigh-Wake Emergency Communications Center (RWECC) is the sole ambulance

dispatch center for Wake County,

and is one of only 139 accredited EMD centers of excellence (ACE) worldwide.