Recurrent opioid toxicity after pre-hospital care of presumed heroin overdose patients.

BACKGROUND: In patients with presumed heroin overdose, the recommended time of observation after reversing heroin toxicity with naloxone varies widely. The aims of this study were to examine the incidence of recurrent opioid toxicity and the time interval in which it occurs after pre-hospital treatment in presumed heroin overdose patients. METHODS: We undertook a retrospective study in Helsinki (population, 560,000). Records were reviewed from 1 January 1995 to 31 December 2000. Patients included were treated by the emergency medical service (EMS) for a presumed heroin overdose. Patients with known polydrug/alcohol use or the use of opioids other than heroin were excluded. The EMS records were compared with the cardiac arrest database and the medical examiners' records. RESULTS: One hundred and forty-five patients were included. The median dose of pre-hospital administered naloxone was 0.4 mg. After pre-hospital care, 84 patients refused further care and were not transported to an emergency department (ED). Seventy-one received pre-hospital naloxone, and no life-threatening events were recorded during a 12-h follow-up period in these patients. After pre-hospital care, 61 patients were transported to an ED. Twelve patients received naloxone in the ED for respiratory depression. All had signs of heroin use-related adverse events within 1 h after receiving pre-hospital naloxone. CONCLUSIONS: Allowing presumed heroin overdose patients to sign out after pre-hospital care with naloxone is safe. If transported to an ED, a 1-h observation period after naloxone administration seems to be adequate for recurrent heroin toxicity.

Outcome after heroin overdose and cardiopulmonary resuscitation.

BACKGROUND: The survival of heroin overdose patients resuscitated from cardiac arrest is reported to be poor. The aim of our study was to investigate the outcome and characteristics of survivors after cardiac arrest caused by heroin overdose. METHODS: This was a retrospective study in a medium-sized city (population, 560,000). Between 1 January 1997 and 31 December 2000, there were 94 combined cardiac arrests caused by acute drug poisonings. The main outcome measure was survival to discharge. RESULTS: Cardiopulmonary resuscitation was attempted in 19 heroin overdose patients (group A) and in 53 patients with cardiac arrest caused by other poisonings (group B). Three (16%) vs. six (11%) patients were discharged alive (group A vs. B, respectively). The survivors in group A had an Emergency Medical Service (EMS)-witnessed cardiac arrest or the Emergency Dispatching Centre was called before the arrest occurred. There was no statistically significant difference between the two groups in terms of survival. Survivors in both groups suffered from acute renal failure (two), hypoglycaemia (four) and hypothermia (three). CONCLUSION: Survival after cardiac arrest caused by heroin overdose is possible if the arrest is EMS witnessed or the Emergency Dispatching Centre is called before the cardiac arrest occurs. In comparison with cardiac arrests caused by other poisonings, there was no difference in survival. The incidence and mechanism of hypoglycaemia should be examined in further studies.

Comparison of 30 and the 100% inspired oxygen concentrations during early post-resuscitation period: a randomised controlled pilot study.

OBJECTIVES: High oxygen concentration in blood may be harmful in the reperfusion phase after cardiopulmonary resuscitation. We compared the effect of 30 and 100% inspired oxygen concentrations on blood oxygenation and the level of serum markers (NSE, S-100) of neuronal injury during the early post-resuscitation period in humans. METHODS: Patients resuscitated from witnessed out-of-hospital ventricular fibrillation were randomised after the return of spontaneous circulation (ROSC) to be ventilated either with 30% (group A) or 100% (group B) oxygen for 60 min. Main outcome measures were NSE and S-100 levels at 24 and 48 h after ROSC, the adequacy of oxygenation at 10 and 60 min after ROSC and, in group A, the need to raise FiO(2) to avoid hypoxaemia. Blood oxygen saturation <95% was the threshold for this intervention. RESULTS: Thirty-two patients were randomised and 28 (14 in group A and 14 in group B) remained eligible for the final analysis. The mean PaO(2) at 10 min was 21.1 kPa in group A and 49.7 kPa in group B. The corresponding values at 60 min were 14.6 and 46.5 kPa. PaO(2) values did not fall to the hypoxaemic level in group A. In another group FiO(2) had to be raised in five cases (36%) but in two cases it was returned to 0.30 rapidly. The mean NSE at 24 and 48 h was 10.9 and 14.2 microg/l in group A and 13.0 and 18.6 microg/l in group B (ns). S-100 at corresponding time points was 0.21 and 0.23 microg/l in group A and 0.73 and 0.49 microg/l in group B (ns). In the subgroup not treated with therapeutic hypothermia in hospital NSE at 24h was higher in group B (mean 7.6 versus 13.5 microg/l, p=0.0487). CONCLUSIONS: Most patients had acceptable arterial oxygenation when ventilated with 30% oxygen during the immediate post-resuscitation period. There was no indication that 30% oxygen with SpO(2) monitoring and oxygen backup to avoid SpO(2)<95% did worse that the group receiving 100% oxygen. The use of 100% oxygen was associated with increased level of NSE at 24h in patients not treated with therapeutic hypothermia. The clinical significance of this finding is unknown and an outcome-powered study is feasible.

Thrombolytic treatment of acute myocardial infarction after out-of-hospital cardiac arrest.

OBJECTIVE: To investigate the safety and efficacy of thrombolytic treatment for an acute myocardial infarction (AMI) immediately after resuscitation in the out-of-hospital setting. DESIGN: Retrospective. SETTING: A middle-sized urban city (population 540000) served by a single emergency medical system using a tiered response with physicians in field. PATIENTS AND METHODS: Sixty-eight patients with an initial diagnosis of AMI who received thrombolytic treatment in an out-of-hospital setting after cardiac arrest and cardiopulmonary resuscitation (CPR) between January 1st 1994 and December 31st 1998. An ECG and the myocardial enzymes (CK, CK-MB, Troponin-T) were used to diagnose AMI. Myocardial reperfusion was assessed by resolution of the ST-segment elevation. Side effects and complications were studied. The quality of secondary survival was evaluated. The Utstein style was used for a uniform style of reporting the cardiac arrest data. RESULTS: The accuracy of prehospital diagnosis was found to be excellent. Retrospective analysis revealed that thrombolytic therapy had been appropriately administered in 64 (94%) of the 68 patients actually treated. Reperfusion was achieved in 71% of the patients. Haemorrhagic complications were few, and included intracranial haemorrhage (one patient), gastrointestinal bleeding (two patients), bleeding from the puncture site (one patient) and epistaxis (one patient). The incidence of hypotension during streptokinase infusion was 22%. Sixty-three (93%) of the patients were admitted alive to the hospital, with 36 subsequently surviving to discharge. CONCLUSIONS: Thrombolytic treatment is a safe and effective treatment in AMI even after out-of-hospital cardiopulmonary resuscitation.

The incidence of out-of-hospital ventricular fibrillation in Helsinki, Finland, from 1994 to 1999.

Early defibrillation by emergency medical services has been a success story in the treatment of ventricular fibrillation. This success has been followed by recommendations to allow public access to defibrillation equipment. We tracked the changes in incidence of ventricular fibrillation from prospectively collected data from the Helsinki Cardiac Arrest Register. We found that the incidence of out-of-hospital ventricular fibrillation of cardiac origin fell by 48% from 1994 to 1999 (p=0.0036). The primary and secondary prevention of coronary artery disease may not be the only reasons for this change and so new public-access defibrillation programmes should be delayed until our findings are confirmed.

Out-of-hospital cardiac arrests of non-cardiac origin. Epidemiology and outcome.

AIMS: The aim of the study was to determine the epidemiology of out-of-hospital cardiac arrests of non-cardiac origin and survival following resuscitation, using the Utstein method of data collection. METHODS AND RESULTS: The study was of prospective cohort design and was conducted in a middle-sized urban city (population 525000) served by a single emergency medical services system. Consecutive out-of-hospital cardiac arrests of non-cardiac origin occurring between 1 January 1994 and 31 December 1995 were included. Survival from cardiac arrest to hospital discharge, and factors associated with survival were considered as main outcome measures. Of the 809 patients, 276 (34.1%) had a cardiac arrest of non-cardiac origin. The mean (SD) age of the patients was 49.8 (20.9) years. Resuscitation was attempted in 204 cases, 82 of whom (40.2%) were hospitalized alive and 23 (11.3%) were discharged. Thirteen (56.5%) of the survivors were discharged neurologically intact or with mild disability (overall performance category I or II). The survivors, during the study period, who suffered an out-of-hospital cardiac arrest of non-cardiac origin comprised 19.2% of all out-of-hospital cardiac arrest survivors. Trauma (62), non-traumatic bleeding (36), intoxication (31), near drowning (22) and pulmonary embolism (18) were the most common aetiologies, comprising 61.2% of cases. The non-cardiac aetiology was suspected pre-hospital in 176 (63.8%) cases; in the remaining cases, the aetiology was revealed only after in-hospital investigations or autopsy. In a logistic regression model, time interval to first responding unit, collapse outside the home, and aetiologies of near-drowning, airway obstruction, intoxication and convulsions were associated with survival. CONCLUSIONS: These results indicate that sudden out-of-hospital cardiac arrest more often has a non-cardiac cause than previously believed. Although survival is not as likely as from cardiac arrest of cardiac origin, since non-cardiac-cause survivors comprise one fifth of all out-of-hospital cardiac arrest survivors, resuscitation efforts are worthwhile.