Reliability of prehospital rating scales for case severity and status change

A randomized controlled feasibility trial comparing safety and effectiveness of prehospital pacing versus conventional treatment: 'PrePACE'

OBJECTIVE

To evaluate the feasibility of a prehospital randomized controlled trial comparing transcutaneous pacing (TCP) with dopamine for unstable bradycardia.

METHODS

Unstable bradycardic patients who failed to respond to a fluid bolus and up to 3mg atropine were enrolled. The intervention was dopamine or TCP with crossover to dopamine if TCP failed. The primary outcome was survival to discharge or 30 days. Randomization compliance, safety, follow-up rates, primary outcome, and sample size requirements were assessed.

RESULTS

Of 383 patients with unstable bradycardia, 151 (39%) failed to respond to atropine or fluid and were eligible for enrollment and 82 (55%) were correctly enrolled. Fifty-five (36%) of eligible patients could not be enrolled for practical reasons; 3 had advance directives, 32 met inclusion criteria on arrival at hospital and in 20 cases, paramedics chose not to enroll based on the circumstances of the case. The remaining 13 were missed cases; 8 were missing randomization envelopes and in 5, the paramedic forgot. Randomization compliance was 95% (78/82). Forty-two (51%) patients were randomized to TCP and seven of these crossed over to dopamine. Two cases were randomized but did not receive the intervention; either due to lack of time or loss of IV access. Three adverse events occurred in each group. Survival to discharge or 30 days in hospital was 70% (28/40) and 69% (29/42) in the dopamine and TCP groups, respectively with 100% follow up. To detect a 10% relative difference in 30 days survival between treatment arms, a sample size of 690 per group would be required.

CONCLUSIONS

It is feasible to conduct a prehospital randomized controlled trial of TCP for unstable bradycardia and a definitive trial would require a multi-centre study.

Effect of socioeconomic status on out-of-hospital transport delays of patients with chest pain

STUDY OBJECTIVES

The effect of socioeconomic status on out-of-hospital care has not been widely examined. We determine whether socioeconomic status was associated with out-of-hospital transport delays for patients with chest pain.

METHODS

A retrospective study of patients with chest pain transported by means of ambulance in Toronto, Ontario, Canada, in 1999 was conducted. The primary outcome measure was the 90th percentile system response interval, with secondary outcomes being the 90th percentile on-scene interval, transport interval, and total out-of-hospital interval. Socioeconomic status was the primary independent variable. Covariates were age, sex, case severity, dispatch and return priority, time and day of transport, paramedic training, and percentage of high-rise apartments in the region.

RESULTS

Four thousand three hundred fifty-six patients met the inclusion criteria. The 90th percentile system response interval and total out-of-hospital interval were 11 minutes and 49 minutes, respectively. In multivariate analyses, the highest socioeconomic status neighborhoods were significantly associated with decreased system response interval (34.0 seconds; 95% confidence interval [CI] 6.2 to 70.9 seconds) and transport interval (132.3 seconds; 95% CI 24.1 to 229.6 seconds). In addition, age (+45.3 seconds per 10 years; 95% CI 13.3 to 75.1 seconds), female sex (+205.0 seconds; 95% CI 78.1 to 287.7 seconds), and advanced care paramedic crews (+371.6 seconds; 95% CI 263.3 to 490.1 seconds) were associated with delays in total out-of-hospital interval. Lastly, calls originating from the highest socioeconomic status neighborhoods were dispatched the highest proportion of advanced care paramedic crews, despite similar dispatch priorities and case severities.

CONCLUSION

High socioeconomic status neighborhoods were associated with shorter out-of-hospital transport intervals for patients with chest pain. In addition, out-of-hospital delays were associated with age, sex, and advanced care paramedic crew type, with calls from the highest socioeconomic status neighborhoods being most likely to receive advanced care paramedic crews.

Effects of prehospital care on outcome in patients with cardiac illness

STUDY OBJECTIVE

To compare outcomes of patients with acute cardiac illness transported by ambulance for whom prehospital care was provided by emergency medical technician-paramedics (EMT-Ps) or EMTs trained in defibrillation (EMT-Ds).

DESIGN

A prospective chart review carried out over 3.5 years.

SETTING

The Hamilton-Wentworth region of Ontario, Canada, which covers 1,136 km2 and includes five receiving hospitals.

PARTICIPANTS

We prospectively identified 8,720 potentially eligible patients from approximately 30,000 who presented to the ambulance service. We reviewed hospital charts to confirm eligibility. The group of 8,720 patients yielded 3,066 patients with acute cardiac illness who met all other eligibility requirements. We excluded patients in cardiac arrest.

RESULTS

Incidence of myocardial infarction (MI), length of hospital stay, and mortality were evaluated. Analysis was performed with chi 2 tests for association, linear regression, and logistic regression. Of the eligible patients who received prehospital EMS care, 783 sustained MIs. The proportions of people discharged alive with the diagnosis of MI did not differ between crew types (P = .16). Average hospital stay was 13 days in both groups for patients with the discharge diagnosis of MI; hospital stay ranged from 9 (EMT-D) to 11 days (EMT-P) for any patient with a discharge diagnosis other than MI. These values were statistically similar. The odds ratio of having had an MI after treatment by an EMT-D crew was 1.02 (95% confidence interval, .86 to 1.21) compared with that for treatment by an EMT-P crew.

CONCLUSIONS

In an urban setting with short (less than 10 minutes) average transport times, the availability of prehospital paramedic care does not affect occurrence of MI, length of hospital stay, or mortality of patients presenting to the EMS system with cardiac illness.

Differential prehospital benefit from paramedic care

STUDY OBJECTIVES

To determine whether prehospital outcome of patients who receive care from emergency medical technicians-paramedic (EMT-Ps) differs from that of patients who receive care from emergency medical technicians-defibrillation (EMT-Ds), as rated by the treating EMTs using standardized scales, and to determine whether the patient's seriousness of illness is relevant to any differential benefit of one level of care over the other.

DESIGN

Historical (retrospective) cohort.

SETTING

An urban and semiurban region of southwest Ontario comprising an area of 1,136 square kilometers (438 square miles) with a population of more than 445,000.

TYPE OF PARTICIPANTS

Patients (10,291) who were transported by the Hamilton-Wentworth EMS system between January 1, 1991, and December 31, 1991.

METHODS AND MEASUREMENTS

EMTs rated the prehospital outcome of their own patients, using scales that had been tested in a previous study. Comparisons between EMT-P- and EMT-D-treated patients were made by chi 2, chi 2 by trend, and Fisher's exact test as appropriate.

RESULTS

More seriously ill or injured EMT-P-treated patients were rated as improved and fewer EMT-P-treated patients were rated as worsened compared with similar patients who were cared for and rated by EMT-Ds. The differential benefit from EMT-P to EMT-D care ranged from 8% to 25% for patients rated as "severe" and from 27% to 49% for patients rated as "life-threatened."

CONCLUSION

According to the ratings of prehospital care providers, patients classified as "severe" or "life-threatened" had their conditions "improve" by the time they arrived at the hospital more often when care was provided by an EMT-P team than when it was provided by an EMT-D team.