Emergency medical dispatch. The first medical response for life-threatening conditions. Assessment and invention of patients with chest pain and/or suspected cardiac arrest

Abstract

Aims: To describe the Emergency Medical Dispatcher's (EMDs) possibility of assessment and intervention of patients reported having chest pain and/or cardiac arrest, with regard to identification of the problem, priority-decision, provision of instructions in dispatcher-assisted bystander cardiopulmonary resuscitation (CPR), and the subsequent outcome in terms of final diagnosis and survival. Methods: Prospective and retrospective observational studies based on registrations made by EMDs in case record forms (during two months, 1993), and in the dispatch protocol (27 months, 1994-1996) and subsequent follow-up in ambulance and hospital files. Evaluations of tape recordings of emergency calls to the EMS dispatch centre, concerning patients treated for out-of-hospital cardiac arrest (99 calls/1986, 100 calls/2000-2001). A qualitative study was used to describe the EMDs perceptions of identifying cardiac arrest, offer and provide instructions in CPR to callers. Ten EMDs were approached for face-to-face interviews in 1997. Results: Among 503 patients reporting chest pain, 68% were judged as having severe chest pain, of which 26% developed acute myocardial infarction (AMI) as compared with 13% among patients judged as having only vague chest pain (p = 0.0004). The EMDs had a strong suspicion of AMI in 36%, a moderate suspicion of AMI in 34%, and a vague or no suspicion in 30%. Among patients with a strong suspicion of AMI, 29% subsequently developed AMI compared with 18% among patients with a moderate suspicion, and 15% among patients with only a vague or no suspicion of AMI (p< 0.001). The study sample size was too small to evaluate the predictive value of various associated symptoms accompanying chest pain. The priority level was similar in patients with and without a life-threatening condition (81% vs. 73% receiving the highest priority). In patients with cardiac arrest outside hospital, more attention should be paid to the detection of these patients by the EMDs, however, when the EMDs had a suspicion, their accuracy was high. Half of witnesses accepted an offer of instructions in CPR, and one-third completed dispatcher-assisted bystander CPR. The comparison between no performance and performance of dispatcher-assisted bystander CPR, suggests an increase in survival from 6% to 9%. Among suspected cardiac arrest cases, EMDs offer CPR instruction to only a small fraction of callers, with an accomplishment in all, of ~8%. However, 30-50% of suspected cardiac arrest cases seemed eligible to be approached with such an offer. A major obstacle was the presentation of suspected agonal breathing, which was estimated to occur in about 30%, and was described as: difficulties breathing, poorly, gasping, wheezing, impaired and occasional breathing. The EMDs have a belief that they are being an empathic authority that relieves the caller of the burden of responsibility, and by meeting the witness mentally, this may enable the caller to act at the scene. The EMDs are dependent on the callers knowledge and trustworthiness, and convincing answers from the caller prompt a more secure feeling in the EMDs, just as caller's lack of knowledge having a negative effect on the EMDs efforts. Conclusion: There was a strong relationship between the EMDs suspicion of AMI and subsequent development of AMI. One-third, however, developed AMI among those where the EMD had had a moderate, vague or no suspicion of AMI. Patients judged to have severe chest pain, developed AMI twice as often as patients judged to have vague pain. Caller's reporting patients with a combination of unconsciousness and agonal breathing or respiratory arrest should be offered dispatcher-assisted CPR instruction. This may improve survival in out-of hospital cardiac arrest.