Methodology-dependent variation in documentation of outcome predictors in out-of-hospital cardiac arrest

The reliability and accuracy of operational system data in a nationwide helicopter emergency medical services mission database

AIM

The aim of this study was to evaluate the reliability and accuracy of documentation in FinnHEMS database, which is a nationwide helicopter emergency service (HEMS) clinical quality registry.

METHODS

This is a nationwide study based on written fictional clinical scenarios. Study subjects were HEMS physicians and paramedics, who filled in the clinical quality registry based on the clinical scenarios. The inter-rater -reliability of the collected data was analyzed with percent agreement and free-marginal multi-rater kappa.

RESULTS

Dispatch coding had a percent agreement of 91% and free-marginal multi-rater kappa value of 0.83. Coding for transportation or mission cancellation resulted in an agreement of 84% and free-marginal kappa value of 0.68. An agreement of 82% and a kappa value of 0.73 for dispatcher coding was found. Mission end, arrival at hospital and HEMS unit dispatch -times had agreements from 80 to 85% and kappa values from 0.61 to 0.73. The emergency call to dispatch centre time had an agreement of 71% and kappa value of 0.56. The documentation of pain had an agreement of 73% on both the first and second measurements. All other vital parameters had less than 70% agreement and 0.40 kappa value in the first measurement. The documentation of secondary vital parameter measurements resulted in agreements from 72 to 91% and kappa values from 0.43 to 0.64.

CONCLUSION

Data from HEMS operations can be gathered reliably in a national clinical quality registry. This study revealed some inaccuracies in data registration and data quality, which are important to detect to improve the overall reliability and validity of the HEMS clinical quality register.

Circadian variation in witnessed out of hospital cardiac arrest

OBJECTIVES

To examine the effect on circadian variation of out of hospital cardiac arrest according to the underlying aetiology and presenting rhythm of arrest, and to explore strategies that might help to improve survival outcome using circadian variation.

DESIGN

Population based retrospective study.

SETTING

County of Nottinghamshire with a total population of 993 914 and an area of 2183 km(2).

SUBJECTS

Between 1 January 1991 and 3 December 1994, all witnessed cardiac arrests attended by the Nottinghamshire Ambulance Service, of which 1196 patients had a cardiac cause for their arrest (ICD, 9th revision, codes 390-414 and 420-429) and 339 had a non-cardiac cause.

RESULTS

The circadian variation of the cardiac cases was not significantly different from that of non-cardiac cases (p = 0.587), even when adjusted for age, sex, or presenting rhythm of arrest. For cardiac cases, the circadian variation of those who presented with ventricular fibrillation was significantly different from those presenting with a rhythm other than ventricular fibrillation (p = 0.005), but was similar to the circadian variation of bystander cardiopulmonary resuscitation (p = 0.306) and survivors (p = 0.542). Ambulance response time was also found to have a circadian variation.

CONCLUSIONS

There is a common circadian variation of out of hospital cardiac arrest, irrespective of underlying aetiology, where the presenting rhythm is other than ventricular fibrillation. This is different from the circadian variation of cases of cardiac aetiology presenting with ventricular fibrillation. The circadian variation of ventricular fibrillation, and consequently survival, may be affected by the availability of bystander cardiopulmonary resuscitation and the speed of ambulance response.

Who gets bystander cardiopulmonary resuscitation in a witnessed arrest?

OBJECTIVE

To identify characteristics associated with provision of bystander CPR in witnessed out-of-hospital cardiac arrest cases.

METHODS

An observational, prospective, cohort study was performed using cardiac arrest cases as identified by emergency medical services (EMS) agencies in Oakland County. MI, from July 1, 1989, to December 31, 1993. All patients who sustained a witnessed arrest prior to arrival of EMS personnel were reviewed.

RESULTS

Of the 927 patients meeting entry criteria, the 229 patients receiving bystander CPR were younger: 60.9 +/- 14.7 vs 67.9 +/- 14.7 years (p < 0.01). Most (76.6%) cardiac arrests occurred in the home. In a multivariate logistic model, only the location of arrest outside the home was a significant predictor of receiving bystander CPR [odds ratio (OR) 3.8; 99% CI 2.5, 5.9]. Arrests outside the home were associated with significantly improved outcome, with 18.2% of out-of-home and 8.2% of in-home victims discharged from the hospital alive (OR 2.5; 99% CI 1.4, 4.4).

CONCLUSION

Patients who have had witnessed cardiac arrests outside the home are nearly 4 times more likely to receive bystander CPR, and are twice as likely to survive. This observation emphasizes the need for CPR training of family members in the authors' locale. This phenomenon may also represent a significant confounder in studies of out-of-hospital cardiac arrest and resuscitation.

Outcome of out-of-hospital cardiorespiratory arrest in south Glamorgan

During 138 weeks an emergency medical service (EMS) of mixed skill-level attempted to resuscitate 954 patients from prehospital cardiac arrest (883 attempts per million population per year); 75% of the arrests were of cardiac cause. This paper is one of the first analyses from europe to use the 'Utstein template' to report outcomes of such arrests. In cases where an arrest rhythm could be recorded, 38.4% were ventricular fibrillation (VF), 45.5% were asystolic, and the remainder were either electromechanical dissociation or respiratory arrests. Using univariate analysis factors associated with a greater likelihood of survival include the presence of a witness, bystander-initiated cardiopulmonary resuscitation (CPR), early CPR and VF as the arrest rhythm. Twenty of 155 cases (13%) survived where VF arrest was witnessed by non-EMS personnel.

Evidence for and impact of selective reporting of trauma triage mechanism criteria

OBJECTIVE

To determine whether out-of-hospital care charts selectively report trauma triage criteria, and the impact of such documentation on triage guideline development.

METHODS

A special structured data instrument that requested the presence or absence of the American College of Surgeons (ACS) trauma triage criteria was completed by emergency medical services (EMS) personnel transporting victims of motor vehicle crashes. The standard written EMS report forms for a subset of 199 patients with at least 1 ACS trauma triage mechanism criterion were reviewed by the investigators. Outcome data were obtained from medical record review. The structured data instrument and the standard EMS report were compared for concordance. The impact of method of data collection on the ability of the ACS criteria to predict patient outcome was determined.

RESULTS

EMS reports and structured data instruments similarly noted the presence of anatomic, physiologic, and "other" trauma triage criteria (p > 0.07 for all individual comparisons). Most mechanism-of-injury criteria noted on the data instrument (pedestrian struck > 20 mph; crash speed > 20 mph; vehicle deformity; compartment intrusion; rollover; and ejection) were infrequently documented on the standard EMS report (median 28.5% noted, range 0-100%). Patients who had mechanism criteria noted on the EMS report were more likely to be admitted to the hospital (44% vs 13%; p = 0.006), to require major operative procedures (10% vs 0%; p = 0.005), and to have prolonged lengths of stay (26% vs 9%; p = 0.02) and injury severity scores > or = 16 (15% vs 3%; p = 0.03) than were patients who had mechanism criteria documented only on the structured data instrument.

CONCLUSIONS

In the authors' EMS system, standard EMS report documentation underreports ACS trauma triage mechanism criteria. This underreporting appears to bias outcome analysis in the direction of a worse outcome and more resource utilization. Reporting of mechanism-of-injury criteria improves with use of a structured data instrument.

Bystander CPR, ventricular fibrillation, and survival in witnessed, unmonitored out-of-hospital cardiac arrest

STUDY OBJECTIVE

To assess whether bystander CPR (BCPR) on collapse affects initial rhythm and outcome in patients with witnessed, unmonitored out-of-hospital cardiac arrest (OHCA).

DESIGN

Prospective cohort study. Student's t test, the chi 2 test, and logistic regression were used for analysis.

SETTING

Suburban emergency medical service (EMS) system.

PARTICIPANTS

Patients 19 years or older with witnessed OHCA of presumed cardiac origin who experienced cardiac arrest before EMS arrival between July 1989 and July 1993.

RESULTS

Of 722 patients who met the entry criteria, 153 received BCPR. Patients who received BCPR were younger than those who did not: 62.5 +/- 15.4 years versus 66.8 +/- 15.1 years (P < .01). We found no differences in basic or advanced life support response intervals or in frequency of AED use. More patients initially had ventricular fibrillation (VF) in the BCPR group: 80.9% versus 61.4% (P < .01). The interval to definitive care for ventricular tachycardia (VT)/VF was longer for the BCPR group (8.59 +/- 5.3 versus 7.45 +/- 4.7 minutes; P < .05). The percentage of patients discharged alive who were initially in VT/VF was higher in the BCPR group: 18.3% versus 8.4% (P < .001). In a multivariate model, BCPR is a significant predictor for VT/VF and live discharge with adjusted ORs of 2.7 (95% CI, 1.7 to 4.4) and 2.4 (95% CI, 1.5 to 4.0), respectively. For those patients in VT/VF, BCPR predicted live discharge from hospital with an adjusted OR of 2.1 (95% CI, 1.2 to 3.6).

CONCLUSION

Patients who receive BCPR are more often found in VT/VF and have an increased rate of live discharge, with controls for age and response and definitive care intervals. For VT/VF patients, BCPR is associated with an increased rate of live discharge.