Bystander initiated and dispatcher assisted cardiopulmonary resuscitation in out-of-hospital cardiac arrest

Abstract

Cardiac arrest (CA) is a common cause of death. In Sweden approximately 6 000-10 000 people annually suffer a CA outside hospital. Cardiopulmonary resuscitation (CPR) can save lives in an out-of-hospital cardiac arrest (OHCA). The aim of this thesis was to describe various aspects of CPR and the emergency medical dispatcher (EMD) organisation to find approaches for enhancing bystander intervention in OHCA.

Methods and results: In Study I, 315 consecutive cases of OHCA during a 3-month period in 2004 were analysed to describe the frequency of as well as hindrance to dispatcher-assisted CPR. Seventy-six cases met the inclusion and exclusion criteria as witnessed, non-traumatic CA and the corresponding tapes recordings of the emergency calls were analyzed. Dispatchers offered bystanders telephone instructions for CPR in 47% (n=36) of cases. Only two bystanders were unwilling to perform CPR. Signs of breathing (agonal respiration) were described in 45% of cases. CPR was offered to 23% (n=10) of patients with agonal respiration versus 92% (n=23) of those without any form of breathing signs (p=0.001).

To evaluate whether tuition in recognition of agonal respiration will improve EMD recognition of CA and subsequent offers of assisted CPR by telephone (T-CPR) was addressed in Study II. In 255 consecutive cases of OHCA during the study period in 2006, 76 cases met the inclusion and exclusion criteria as witnessed, non-traumatic CA and the corresponding tape recordings of the emergency calls were analyzed. The findings from the 76 tape recordings from study I were used as a historical control group. The EMD offered CPR instructions in 36 (47%) calls before tuition compared to 52 (68%) calls after a 1-day tuition in agonal respiration (p=0.01). An increase was also shown after the tuition regarding offered dispatcher-assisted CPR in cases with agonal respiration, 23% (2004) vs. 56% (2006) (p=0.006).

To evaluate standard bystander CPR (mouth-to-mouth ventilation with chest compressions) versus chest compression only CPR by bystanders Study III included cases of OHCA who had received any form of bystander CPR and who had been reported to the Swedish Cardiac Arrest Register between 1990 and 2005. Crew witnessed cases of OHCA were excluded. Information as to type of CPR that had been given was missing in 1 465 (11%) patients. Among the remaining 11 275 patients, 8 209 had (73%) received standard CPR, whereas 1 145 patients (10%) had received compressions only. There was no significant difference in 1-month survival in patients who received standard CPR compared with those given compression only CPR.

In Study IV calls concerning possible cases of witnessed OHCA were randomized by EMDs to receive pre-arrival instructions of either compression only CPR or standard CPR. The primary end point was survival to 30 days. Data were collected between February 2005 to January 2009 for 3 809 patients. The intention-to-treat analysis included 1 276 patients who did meet the inclusion and exclusion criteria. Six hundred and eleven (620) patients were randomly assigned to receive instructions for compression only CPR and 656 patients for standard CPR. Survival in both groups was similar with 8.7% (54/620) of the patients who received compressions only CPR and 7.0% (46/656) in the standard CPR group being alive at 30 days (1.7 percentage points difference, 95% CI, -1.2% to 4.6%; p < 0.30).

Conlusions: EMDs do offer telephone guided CPR to bystanders in cases of OHCA but not to all those cases where it is indicated. Agonal respiration in association with CA is often a hindrance to offering T-CPR. Very few witnesses who were offered telephone-guidance for CPR refused to participate. A brief tutorial for EMDs comprising the signs and implications of agonal respiration led to a significantly higher proportion of bystanders who were offered TCPR. In a register study of CPR in patients suffering OHCA no significant difference was found in 1-month survival in patients who received standard bystander CPR as compared to those given compressions only. A prospective randomized study showed no significant difference between pre-arrival instructions for compression only CPR compared to standard CPR in witnessed OHCA which gives further support to the hypothesis that compression-only CPR is the preferred method in bystander CPR.