Prearrest signs of shock and respiratory insufficiency in out-of-hospital cardiac arrests witnessed by crew of the emergency medical service☆☆☆★
Received 13 January 2008; received in revised form 1 March 2008; accepted 15 March 2008.
Abstract
Aim
The objective of this study is to determine whether prearrest shock and respiratory insufficiency influence outcome in patients with emergency medical service–witnessed out-of-hospital cardiac arrest.
Methods
Analysis of data from a cardiac arrest database and data from the ambulance charts was performed. For the purpose of the study, shock was defined as prearrest heart rate below 40 or above 140/min, systolic blood pressure as below 90 mm Hg, and respiratory insufficiency as respiratory rate above 36 or oxygen saturation below 90%. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.
Results
Of a total of 303 patients, 81% had prearrest shock or respiratory insufficiency. Mortality was higher in these patients indicated by fewer with return of spontaneous circulation (43% vs 75%, P < .001), and lower survival to hospital admission (31% vs 71%, P < .001) and to discharge (13% vs 59%, P < .001). Independent predictors of mortality were age (OR, 1.04; CI, 1.0-1.06), initial rhythm other than ventricular fibrillation or ventricular tachycardia (OR, 32.9; CI, 10.9-99.0), and respiratory insufficiency (OR, 4.2; CI, 1.4-12.5).
Conclusions
Shock and respiratory depression are common among patients with out-of-hospital cardiac arrest witnessed by the emergency medical service, and these patients have a high mortality when compared with patients without shock or respiratory failure.
aDepartment of Anaesthesiology and Intensive Care Medicine, Helsinki University Central Hospital, PO Box 340, FIN-00029 HUS, Finland
bHelsinki EMS of Helsinki University Hospital, Finland
Corresponding author.
☆ The present study was supported by unrestricted grants from Stockmann Stiftelsen and Medicinska Understödsföreningen Liv och Hälsa rf.
☆☆ The present study has not been previously submitted, and it is not under consideration in any other journal. An abstract including the main findings of the present study has been accepted for presentation and for publication (abstract in supplement of Resuscitation) at the European Resuscitation Council's congress to be held in Ghent, Belgium, in May 2008.
★ The patients included in the present study are from a prospectively collected out-of-hospital cardiac arrest database. From this database, 2 recent reports (Väyrynen et al. Acta Anaesthesiol Scand 2007, Väyrynen et al. Resuscitation 2007) have been published. In these reports, the patients in this submitted report are included as a subset. These 2 reports, however, focused on outcome of asystole and pulseless electrical activity in out-of-hospital cardiac arrest overall. The most important data in this submitted report, that is, vital signs before the arrest, were not analyzed or reported.
ABSTRACT