The present study included patients from three emergency medical service (EMS) systems in southern Finland, the paramedic-staffed EMS system in the city of Tampere and the physician-staffed helicopter EMS (HEMS) systems in Helsinki and Turku areas, between August 2001 and March 2003. For clarity, the Helsinki area HEMS serves areas surrounding the city of Helsinki, and the city itself is covered by a separate EMS system not included in this study. In Finland, majority of physicians in HEMS systems are specialists in anaesthesiology and intensive care, whereas paramedics undergo 3–4 years of education in emergency medicine.
Originally, the data were collected prospectively for a study with a focus on regurgitation during resuscitation regardless of the initial rhythm. The same database was now retrospectively used for this study, which is a post hoc-analysis with a focus on the long-term outcome of patients with PEA.
All consecutive patients more than 16 years of age, who suffered an OHCA of presumed cardiac origin with PEA as the initial cardiac rhythm and in whom resuscitation was attempted were included. PEA was defined as monitored electrical activity with no detectable pulse. As defined in the 2004 Utstein guidelines, the cause of arrest was presumed to be of cardiac origin when no external cause such as trauma, intoxication, airway obstruction, drowning or haemorrhage was evident. Patients with a disease at a terminal stage, e.g. end-stage malignancy, were excluded. Dispatch centre personnel provided basic life saving instructions to caller if CA was recognized. Patients with PEA were treated according to current guidelines during the study period: endotracheal intubation was used to secure airway and epinephrine was given in 1mg boluses every 3–5 minutes and possible subsequent VF was defibrillated. As a specific treatment for suspected pulmonary embolism causing PEA, all EMS systems were able to provide thrombolysis. At the time of the study period, therapeutic hypothermia was not routinely provided for these patients.
In the present study, assessment of long-term survival was performed after 1 and 5 years following OHCA. One of the authors (SS) evaluated the premorbid CPC and CPC one year after OHCA retrospectively based on patient medical records. The CPC –classification is a five-stage scale of neurological state. Class 1 corresponds to good cerebral performance with no or only mild neurologic or psychological defect, class 2 corresponds to moderate cerebral disability with sufficient cerebral function for independent activities of daily life. Class 3 indicates severe cerebral disability with dependence on others for daily support because of impaired cerebral function. Class 4 stands for coma or vegetative state without interaction with the environment and Class 5 means brain death. Briefly, classes 1–2 correspond to sufficient cerebral function for independent activities of daily life, while classes 3–5 reflect dependency on others. We estimated whether a long-term change in neurological status using the CPC-classification had occurred after OHCA with PEA as the initial rhythm.
The National registry of Statistics Finland was used to evaluate the time and cause of death (COD) in the non-surviving victims of pre-hospital PEA. The patients' medical records from receiving hospitals were used to obtain the cause of OHCA of patients who survived until follow-up.
We sent a fifteen dimensional (15D) questionnaire of health-associated quality of life to the long-term survivors. The 15D-questionnaire is validated in the Finnish National Centre for Health Program Evaluation and includes 15 questions describing self-assessed performance in activities of daily life[16, 17]. If a patient was unable to answer the questionnaire because of disability, his/her next of kin was asked to fill the form in co-operation with the patient.
The study protocol was approved by the ethical review board of the Helsinki University Hospital.
Statistical analyses were performed using the SPSS for Windows V16.0-software (SPSS Inc., Chicago, IL, USA). Chi-Square Test was used for categorical variables. Statistical significance was set at p <0.05. The data are presented as mean ± SD unless otherwise indicated. 95% confidence intervals (CI) were calculated for proportions.