Andrew K Marsden

Effect of reducing ambulance response times on deaths from out of hospital cardiac arrest: cohort study

Abstract Objectives: To determine the association between ambulance response time and survival from out of hospital cardiopulmonary arrest and to estimate the effect of reducing response times. Design: Cohort study. Setting: Scottish Ambulance Service. Subjects: All out of hospital cardiopulmonary arrests due to cardiac disease attended by the Scottish Ambulance Service during May 1991 to March 1998. Main outcome measures: Survival rate to hospital discharge and potential improvement from reducing response times. Results: Of 13 822 arrests not witnessed by ambulance crews but attended by them within 15 minutes, complete data were available for 10 554 (76%). Of these patients, 653 (6%) survived to hospital discharge. After other significant covariates were adjusted for, shorter response time was significantly associated with increased probability of receiving defibrillation and survival to discharge among those defibrillated. Reducing the 90th centile for response time to 8 minutes increased the predicted survival to 8%, and reducing it to 5 minutes increased survival to 10-11% (depending on the model used). Conclusions: Reducing ambulance response times to 5 minutes could almost double the survival rate for cardiac arrests not witnessed by ambulance crews. What is already known on this topic Three quarters of all deaths from myocardial infarction occur after cardiac arrest in the community Survival after out of hospital arrest is much lower in the United Kingdom than the United States What this study adds Ambulance response times are independently associated with defibrillation and survival Decreasing the target for response to 90% of calls from 14 minutes to 8 minutes would increase survival from 6% to 8% A response time of 5 minutes would increase survival to 10-11%

Presentation, management, and outcome of out of hospital cardiopulmonary arrest: comparison by underlying aetiology

Objective: To describe and compare presentation, management, and survival by aetiology of cardiopulmonary arrest. Design, setting, and patients: A retrospective cohort study was undertaken of all 21 175 first out of hospital cardiopulmonary arrests in Scotland between May 1991 and March 1998. Main outcome measure: Discharge alive from hospital. Results: Presumed cardiac disease accounted for 17 451 cases (82%), other internal aetiologies for 1814 (9%), and external aetiologies for 1910 (9%). Arrests caused by presumed cardiac disease had a better risk profile in terms of presence of a witness, bystander cardiopulmonary resuscitation, call–response interval, and use of defibrillation; 1265 (7%) of those who arrested from presumed cardiac disease were discharged alive, compared with only 77 (2%) of those with non-cardiac disorders (p < 0.001). Among those defibrillated, call–response interval was associated with survival following arrests from both presumed cardiac and non-cardiac causes (p < 0.001). Conclusions: Out of hospital cardiopulmonary arrests from non-cardiac causes were associated with worse crude survival than arrests from cardiac causes. Improvements in call–response interval and basic life support skills in the community would improve survival irrespective of the aetiology and should therefore be encouraged.

Potential impact of public access defibrillators on survival after out of hospital cardiopulmonary arrest: retrospective cohort study

Abstract Objective: To estimate the potential impact of public access defibrillators on overall survival after out of hospital cardiac arrest. Design: Retrospective cohort study using data from an electronic register. A statistical model was used to estimate the effect on survival of placing public access defibrillators at suitable or possibly suitable sites. Setting: Scottish Ambulance Service. Subjects: Records of all out of hospital cardiac arrests due to heart disease in Scotland in 1991-8. Main outcome measures: Observed and predicted survival to discharge from hospital. Results: Of 15 189 arrests, 12 004 (79.0%) occurred in sites not suitable for the location of public access defibrillators, 453 (3.0%) in sites where they may be suitable, and 2732 (18.0%) in suitable sites. Defibrillation was given in 67.9% of arrests that occurred in possibly suitable sites for locating defibrillators and in 72.9% of arrests that occurred in suitable sites. Compared with an actual overall survival of 744 (5.0%), the predicted survival with public access defibrillators ranged from 942 (6.3%) to 959 (6.5%), depending on the assumptions made regarding defibrillator coverage. Conclusions: The predicted increase in survival from targeted provision of public access defibrillators is less than the increase achievable through expansion of first responder defibrillation to non-ambulance personnel, such as police or firefighters, or of bystander cardiopulmonary resuscitation. Additional resources for wide scale coverage of public access defibrillators are probably not justified by the marginal improvement in survival.

Survival of 1476 patients initially resuscitated from out of hospital cardiac arrest.

Abstract Objectives: To determine the short and long term outcome of patients admitted to hospital after initially successful resuscitation from cardiac arrest out of hospital. Design: Review of ambulance and hospital records. Follow up of mortality by “flagging” with the registrar general. Cox proportional hazards analysis of predictors of mortality in patients discharged alive from hospital. Setting: Scottish Ambulance Service and acute hospitals throughout Scotland. Subjects: 1476 patients admitted to a hospital ward, of whom 680 (46%) were discharged alive. Main outcome measures: Survival to hospital discharge, neurological status at discharge, time to death, and cause of death after discharge. Results: The median duration of hospital stay was 10 days (interquartile range 8-15) in patients discharged alive and 1 (1-4) day in those dying in hospital. Neurological status at discharge in survivors was normal or mildly impaired in 605 (89%), moderately impaired in 58 (8.5%), and severely impaired in 13 (2%); one patient was comatose. Direct discharge to home occurred in 622 (91%) cases. The 680 discharged survivors were followed up for a median of 25 (range 0-68) months. There were 176 deaths, of which 81 were sudden cardiac deaths, 55 were non-sudden cardiac deaths, and 40 were due to other causes. The product limit estimate of 4 year survival after discharge was 68%. The independent predictors of mortality on follow up were increased age, treatment for heart failure, and cardiac arrest not due to definite myocardial infarction. Conclusion: About 40% of initial survivors of resuscitation out of hospital are discharged home without major neurological disability. Patients at high risk of subsequent cardiac death can be identified and may benefit from further cardiological evaluation. Key messages Nearly 70% of patients discharged after cardiac arrest are alive four years after the event Patients whose cardiac arrest is not due to definite myocardial infarction require further cardiological assessment

Cost effectiveness and cost utility model of public place defibrillators in improving survival after prehospital cardiopulmonary arrest

Objective To determine the cost effectiveness and cost utility of locating defibrillators in all major airports, railway stations, and bus stations throughout Scotland. Design Economic modelling exercise with data from Heartstart (Scotland). Parameters used in economic model included direct costs derived for increased accident and emergency attendances, increased hospital bed days, purchase and maintenance of defibrillators, and training in their use; life years gained calculated from increased discharges from hospital and mean survival after discharge; utility (quality of life) obtained from published data. Sensitivity analyses tested the robustness of model. Future gains discounted at 1.5% a year and future costs at 6%. Setting Whole of Scotland. Subjects Records of all prehospital cardiac arrests due to presumed heart disease that occurred in a major airport, railway, or bus station between May 1991 and March 1998 and were not witnessed by ambulance or medical staff. Main outcome measures Observed survival to hospital admission and observed survival to discharge. Predicted survival calculated by applying observed survival in patients attended by ambulance staff within three minutes to those who waited longer. Results The total discounted direct costs were £18 325 a year. The cost per life year gained was £29 625 (

Seasonal variations in out of hospital cardiopulmonary arrest

49 625, €;43 151) and the cost per quality adjusted life year (QALY) gained was £41 146 (

Getting the right ambulance to the right patient at the right time

68 924, €;59 932). More widespread provision of public place defibrillators would increase these figures. Conclusions The cost per QALY calculated for public place defibrillators represents poorer value for money than some alternative strategies for improving survival after prehospital cardiopulmonary arrest, such as the use of other trained first responders. The figure exceeds the commonly discussed cut off levels for funding in the United Kingdom and United States of £30 000 and

Case report — the successful use of naloxone in an asystolic pre-hospital arrest

50 000 per QALY, respectively.

United Kingdom resuscitation outcome study

OBJECTIVE To determine whether there are seasonal variations in survival following out of hospital cardiopulmonary arrest. DESIGN Prospective cohort study using the Heartstart (Scotland) database. SETTING All of Scotland. PATIENTS 10 890 people who suffered out of hospital cardiopulmonary arrest in the summer or winter between December 1988 and August 1997 inclusive. INTERVENTION Univariate comparisons of 5406 arrests occurring in summer with 5484 in winter, in terms of patient characteristics, management, and survival using χ2 and Mann-Whitney U tests. Multivariate analysis of the association between season and survival following adjustment for case mix. MAIN OUTCOMES MEASURES Survival to discharge from hospital, survival pre-admission, in-hospital survival. RESULTS Only 6% of people who arrested in winter survived to discharge, compared to 8% of those who arrested in summer (odds ratio 0.77, p < 0.001). People who arrested in winter had a poorer risk profile in that they were older, more likely to arrest at home, less likely to have a witness, and less likely to receive defibrillation. However, after adjustment for case mix, people who arrested in winter were still 19% less likely to survive compared to those who arrested in summer. Deaths pre-admission were significantly higher in winter (odds ratio 1.18, p < 0.05) but in-hospital deaths were not. CONCLUSIONS People who suffer cardiopulmonary arrest in winter have a significantly lower likelihood of surviving. This is, in part, caused by the higher frequency of a number of recognised risk factors. However, their prognosis remains poorer even after adjustment for these factors.

Einfache lebensrettende Sofortmaßnahmen beim Erwachsenen

This paper outlines recent developments in dispatching ambulances according to the clinical needs of the patient. Criteria Based Dispatch (CBD) uses accurate and effective interrogation of the caller, with reference to clinically approved guidelines, to ensure that the appropriate level of ambulance support is deployed. The pattern of calls in Glasgow, UK, was monitored in order to evaluate CBD in this context, and the potential benefits of adopting the system are summarised.