Out-of-Hospital Cardiac Arrest in Central Norway: Prehospital management and outcome in urban versus rural areas

Abstract

Bakgrunn: Prehospital hjertestans er hevdet å være den mest tidskritiske akuttmedisinske tilstanden utenfor sykehus. Håndtering kan være særlig utfordrende i landlige områder, og flere tidligere studier har funnet redusert overlevelse etter prehospital hjertestans i landlige strøk. Hensikten med denne studien var å beskrive kjennetegn ved ambulansebehandlet hjertestans i St. Olavs Hospital helseforetak, og identifisere mulige forskjeller i prehospital håndtering og 30 dagers overlevelse i urbane og landlige strøk. Metode: Data på pasienter med prehospital hjertestans dokumenteres rutinemessig fra Akuttmedisinsk kommunikasjonssentral, ambulanse- og luftambulansejournaler. Data på pasientgruppen fra 1.januar 2019 til 31.desember 2019 ble eksportert og analysert i Microsoft Excel og IBM-SPSS Statistics v. 26.0. Variabler ble sammenlignet ved bruk av Fishers eksakte test for kategoriske variabler og Mann-Whitney U test for kontinuerlige variabler. Resultater: Studieperioden inkluderte 162 pasienter (urban: n=90, landlig: n=72). Det var ingen forskjell mellom urbane og landlige pasienter med tanke på hjerte-lungeredning (HLR) av tilstedeværende (urban: 80.8%, landlig: 81.2%, p=1.000) eller HLR av førsterespondenter (urban: 7.8%, rural: 14.9%, p=0.194). Flere landlige enn urbane pasienter hadde påkoblet automatisk ekstern defibrillator (AED) før ambulanseankomst, men forskjellen var ikke statistisk signifikant (urban: 11.4%, landlig: 18.8%, p=0.249). Median responstid var signifikant kortere i urbane strøk (Md=8:00 m:s, IQR=5:43-11:02) sammenliknet med landlige strøk (Md=14.29 m:s, IQR= 7:03-26.57) (p<0.001). Det var ingen statistisk signifikant forskjell i andel av urbane og landlige pasienter som fikk vedvarende egensirkulasjon (ROSC) prehospitalt (urban: 32.2%, landlig: 20.8%, p=0.114). Derimot var median tid fra ambulanseankomst til vedvarende ROSC signifikant lavere i urbane strøk (Md=27:59 m:s, IQR= 14:30-38:29) sammenliknet med landlige strøk (Md=40:59, IQR= 33:59-65:59) (p=0.007). Det var ingen statistisk signifikant forskjell i 30 dagers overlevelse mellom pasientgruppene (urban: 16.7%, landlig: 13.9%, p=0.666). Konklusjon: I likhet med tidligere studier fant denne studien at responstid var signifikant lengre i landlige sammenlignet med urbane strøk. I motsetning til flere tidligere studier, fant denne studien ingen forskjell i 30 dagers overlevelse mellom urbane og landlige pasientgrupper. Det kan være fordi antall pasienter i denne studien var begrenset, og fordi det var flere utelatte variabler.

Background: Out-of-hospital-cardiac arrest (OHCA) is claimed to be the most time-critical emergency in the prehospital setting. Management of OHCA may be particularly challenging in remote areas, and some studies have shown decreased survival rate after OHCA in rural areas. The purpose of this study was to describe the characteristics of emergency medical service (EMS) resuscitated OHCAs in St. Olav’s Hospital Trust, Central Norway, and identify possible differences in the prehospital management and 30-day survival between urban and rural areas. Methods: Data on OHCA patients are routinely collected from the emergency medical dispatch center (EMDC) and from ground ambulances and helicopter emergency medical services (HEMS) records. Data on EMS resuscitated OHCA patients, from January 1st, 2019 to December 31st, 2019, was exported and analyzed using Microsoft Excel and IBM-SPSS Statistics v. 26.0. Variables of interest were compared using the Fisher’s exact test for categorical variables, and the Mann-Whitney U test for continuous variables. Results: The study period included 162 patients (urban: n=90, rural: n=72). There was no significant difference between the urban and rural areas in the rates of bystander cardiopulmonary resuscitation (CPR) (urban: 80.8%, rural: 81.2%, p=1.000) or first responder CPR (urban: 7.8%, rural: 14.9%, p=0.194). More rural than urban patients had attached automated external defibrillator (AED) prior to EMS arrival, but the difference was not significant (urban: 11.4%, rural: 18.8%, p=0.249). The median response time was significantly lower in urban areas (Md=8:00 m:s, IQR=5:43-11:02) compared to rural areas (Md=14.29 m:s, IQR= 7:03-26.57) (p<0.001). There was no significant difference in the rate of sustained return of spontaneous circulation (ROSC) in the field between the urban and rural patient groups (urban: 32.2%, rural: 20.8%, p=0.114). However, median time from EMS arrival until sustained ROSC was significantly lower in urban areas (Md=27:59 m:s, IQR= 14:30-38:29) than in rural areas (Md=40:59 m:s, IQR= 33:59-65:59) (p=0.007). There was no significant difference in 30-day survival between the patient groups (urban: 16.7%, rural: 13.9%, p=0.666). Conclusion: Like previous studies, the present study found that EMS response time was significantly longer in the rural areas compared to urban areas. In spite of this, there was no significant difference in 30-day survival between the urban and rural groups, unlike what several other studies have suggested. However, the patient number in the present study was limited, and there were several important omitted variables.