Effects of prehospital care on outcome in patients with cardiac illness

Advanced Life Support for out-of-hospital Chest Pain: The Opals Study

Context: As many as 14% of patients transported by ambulance with chest pain die prior to hospital discharge. To date, no high-quality controlled trials have revealed that prehospital advanced life support interventions affect survival for these patients.Objective: The Ontario Prehospital Advanced Life Support (OPALS) Study assessed the effect of adding an advance life support service to an existing basic life support emergency medical service program, on the rate of mortality and morbidity for patients with out-of-hospital chest pain.Design: Controlled clinical trial comparing survival for 9 months before and 9 after instituting an advanced life support program.Setting: Thirteen urban and suburban Ontario communities (populations ranging from 30,000 to 750,000; total, 2.5 million).Patients: All adult patients with a primary complaint of chest pain and transported by paramedics to the emergency department.Intervention: Paramedics were trained in standard advanced life support, which includes endotracheal intubation, intravenous furosemide and morphine, oral ASA, and sublingual NTG. Emergency medical services within each community had to meet predefined criteria in order to qualify for the advanced life support phase.Main Outcome Measure: Survival to hospital discharge.Results: Overall, 12,168 patients were enrolled in either the basic life support phase (N = 5,788) or the advanced life support phase (N = 6,380). The rate of mortality significantly decreased from 4.3% in the basic life support phase to 3.2% in the advanced life support phase (absolute change 1.1, 95% CI 0.4-1.8, P = 0.0013). We also demonstrated a decrease in mortality for the subgroup of patients with a discharge diagnosis of myocardial infarction (13.1 percent vs 8.2 percent, P = 0.002).Conclusions: The addition of a prehospital advanced life support program to an existing basic life support emergency medical service was associated with a significant decrease in the mortality rate among patients complaining of chest pain. Future research should clarify the most effective interventions and target specific populations.ClinicalTrials.gov Identifier: NCT00212953.

Does Advanced Life Support Provide Benefits to Patients?: A Literature Review

Introduction:

Emergency medical services have invested substantial resources to establish advanced life support (ALS) programs. However, it is unclear whether ALS care provides better outcomes to patients compared to basic life support (BLS) care.

Objective:

To evaluate the current evidence regarding the benefits of ALS.

Methods:

Electronic medical databases were searched to identify articles that directly compared ALS versus BLS care. A total of 455 articles were found. Articles were excluded for the following reasons: (1) the article was not written in English; (2) BLS response was not compared to an ALS response; (3) a physician or nurse was included as part of the ALS response; (4) it was an aeromedical response; or (5) defibrillation was included in the ALS, but not the BLS, scope of care. Twenty-one articles met the inclusion criteria for this literature review.

Results:

Results were divided into four categories: (1) trauma; (2) cardiac arrest; (3) myocardial infarction; and (4) altered mental status.

Trauma:

The majority of articles showed that ALS provided no benefits over BLS in urban trauma patients. In fact, most studies showed higher mortality rates for trauma patients receiving ALS care. Further research is needed to evaluate the benefits of ALS for rural trauma patients, and whether ALS care improves outcomes in subgroups of urban trauma patients.

Cardiac Arrest:

Cardiac arrest studies show that early CPR plus early defibrillation provide the greatest improvement in survival. However, most cardiac arrest research includes defibrillation as an ALS skill which has now moved into the BLS scope of care. The 2004 multi-center OPALS study provided good evidence that ALS does not improve cardiac arrest survival over early defibrillation. Further research is needed to address whether any ALS interventions improve cardiac arrest outcome.

Myocardial Infarction:

Only one study directly compared the outcome of BLS and ALS care on myocardial infarction. The study found no difference in outcomes between BLS and ALS care in an urban setting.

Advanced Life Support:

Only one study directly compared the outcome of BLS and ALS care on patients with altered mental status. The study found that the same number of patients had improved to “alert” on arrival at the emergency department, but there was a decreased length of emergency department stay for patients treated by ALS for hypoglycemia.

Limitations:

This review article does not take into account the benefits of ALS interventions, such as thrombolytics, dextrose, or nitroglycerin, since no studies directly compared these interventions to BLS care. Furthermore, only one study in this literature review was a large, multi-center trial.

Conclusions:

ALS shows little, if any, benefits for urban trauma patients. Cardiac arrest studies show that ALS does not provide additional benefits over BLS-defibrillation care, but more research is needed in this area. In two small studies, ALS care did not provide benefits over BLS care for patients with myocardial infarctions or altered mental status. Larger-scale studies are needed to evaluate which specific ALS interventions improve patient outcomes.

The Efficacy of Advanced Life Support: A Review of the Literature

Introduction:

Jurisdictions throughout the United States and some other parts of the world have invested substantial time and resources into creating and sustaining a prehospital advanced life support (ALS) system without knowing whether the efficacy of ALS-level care had been validated scientifically. In recent years, it has become fashionable for speakers before large audiences to declare that there is no scientific evidence for the clinical effectiveness of ALS-level care in the out-of-hospital setting. This study was undertaken to evaluate the evidence that pertains to the efficacy of ALS-level care in the current scientific literature.

Methods:

An extensive review of the available literature was accomplished using computerized and manual means to identify all applicable articles from 1966 to October, 1995. Selected articles were read, abstracted, analyzed, and compiled Each article also was categorized as presenting evidence supporting or refuting the clinical efficacy of ALS-level care, and a list was constructed that pointed to where the preponderance of the evidence lies.

Results:

Research in this field differs widely in terms of methodological sophistication. Of the 51 articles reviewed, eight concluded that ALS-level care is not any more effective than is basic life support, seven concluded that it is effective in some applications but not for others, and the remainder demonstrated effectiveness. The strongest support for ALS-level care was in the area of responses to victims of cardiac arrest, whereas somewhat more divergent findings related to trauma or non condition-specific studies.

Conclusion:

While not unanimous, the predominant finding of recent research into the clinical effectiveness of advanced life support demonstrates improved effectiveness over basic life support for patients with certain pathologies. More outcomes-based research is needed.

Is advanced life support better than basic life support in prehospital care? A systematic review

BACKGROUND

Prehospital care is classified into ALS- (advanced life support) and BLS- (basic life support) levels according to the methods used. ALS-level prehospital care uses invasive methods, such as intravenous fluids, medications and intubation. However, the effectiveness of ALS care compared to BLS has been questionable.

AIM

The aim of this systematic review is to compare the effectiveness of ALS- and BLS-level prehospital care.

MATERIAL AND METHODS

In a systematic review, articles where ALS-level prehospital care was compared to BLS-level or any other treatment were included. The outcome variables were mortality or patient's health-related quality of life or patient's capacity to perform daily activities.

RESULTS

We identified 46 articles, mostly retrospective observational studies. The results on the effectiveness of ALS in unselected patient cohorts are contradictory. In cardiac arrest, early cardiopulmonary resuscitation and defibrillation are essential for survival, but prehospital ALS interventions have not improved survival. Prehospital thrombolytic treatment reduces mortality in patients having a myocardial infarction. The majority of research into trauma favours BLS in the case of penetrating trauma and also in cases of short distance to a hospital. In patients with severe head injuries, ALS provided by paramedics and intubation without anaesthesia can even be harmful. If the prehospital care is provided by an experienced physician and by a HEMS organisation (Helicopter Emergency Medical Service), ALS interventions may be beneficial for patients with multiple injuries and severe brain injuries. However, the results are contradictory.

CONCLUSIONS

ALS seems to improve survival in patients with myocardial infarction and BLS seems to be the proper level of care for patients with penetrating injuries. Some studies indicate a beneficial effect of ALS among patients with blunt head injuries or multiple injuries. There is also some evidence in favour of ALS among patients with epileptic seizures as well as those with a respiratory distress.

Evaluation of emergency medical services systems: a classification to assist in determination of indicators

Emergency medical services (EMS) systems, and prehospital care are difficult to evaluate. Accordingly, the true efficacy and value of such systems are difficult to determine. The multitude of variations and combinations of involved factors makes standardisation and comparison difficult, and universal indicators are hard to develop. Various attempts have been made to determine valid indicators of effectiveness, but there has been little success. Prehospital care has been seen by some as a single entity. As a result, experience from well resourced first world trauma centres has been taken, by many, to be applicable to all prehospital situations. This article attempts to assist in the development of valid EMS indicators of performance and effectiveness by categorising prehospital scenarios into a classification reflecting the reality of their conditions of practice.

Acute myocardial infarction: does pre-hospital treatment increase survival?

The aim of this study was to assess the impact of a mobile emergency care unit (MECU) staffed with an anaesthetist, in terms of increased survival among patients with acute myocardial infarction (MI). The setting was an urban area with 330 000 inhabitants. This was a quasi-experimental before-and-after-study including consecutive emergency calls during September to November 1996 (Period 1, without the MECU) and September to November 1997 (Period 2, including the MECU). Fifty-four ambulance patients had their MI diagnosis confirmed at hospital during Period 1, and another 54 in Period 2. The 28-day mortality was collected from relevant registers. Twenty-four (44%) of Period 2 patients were transported by the MECU. MECU patients had lower systolic blood pressure (SBP) than other patients, both before and after hospital admission. Nitroglycerine treatment was relatively frequent in MECU patients, and cardioversion, anaesthesia and intubation was applied exclusively in these patients. After arrival at hospital, MECU patients had thrombolysis relatively often (46% versus 23% in other Period 2 patients) but percutaneous transluminal coronary angioplasty (PTCA) relatively infrequently (21% vs 30%). The total mortality was significantly lower in Period 2 than in Period 1 patients (11% vs 21%, <0.025), irrespective of differences in the distribution of age, gender, pulse and SBP, measured at hospital. Also, the more specific MECU use, alone and in combination with subsequent PTCA treatment, was found to be associated with prolonged survival. Pre-hospital treatment by an MECU staffed by an anaesthetist and/or having a PTCA seems to be associated with prolonged survival in acute MI patients. It must be underscored that these observations have been based on quasi-experimental rather than randomized experimental data.

Paramedic decisions with placement of out-of-hospital intravenous lines

To determine the incidence of unused out-of-hospital intravenous line (IV) placements, we prospectively studied IV placement in emergency medical services (EMS) patients. Unused IV placement was defined as any patient having an EMS initiated IV that was not used for fluid bolus or medication administration in the field or in the emergency department (ED). Data were analyzed on placement and use of IV lines in the field and in the ED, transport time, years of paramedic practice, and paramedic student presence. Of 290 patients, 165 had an IV initiated (147) or attempted (18). Twenty-nine percent (84 of 290) of the patients received an unused EMS IV. One hundred twenty-five patients had no IV initiated by EMS. Seven subsequently had an IV started and used in the ED, for an undertreatment rate of 2.4% (7 of 290). The presence of a paramedic student increased the odds of an unused IV 1.4 (95% CI, 1.1 to 2.0). IVs are frequently started and not used.

Emergency medical service agency definitions of response intervals

STUDY OBJECTIVE

There is a time continuum from emergency medical services (EMS) dispatch, response, scene, transport, and arrival at the hospital. Previous research has documented favorable patient outcome with short response intervals; however, these studies revealed the documentation of EMS time intervals is not always consistent. This study evaluates how agencies estimate these times and factors that may affect the length of response intervals.

METHODS

The study used a mail questionnaire to assess factors related to response intervals and to determine how agencies define and record response intervals. All ground-based EMS agencies in a southwestern state were invited to participate in the survey. Univariate and stratified data analyses compared definitions of response intervals.

RESULTS

Agencies varied as to how they defined the start and end of the response. Fifty-six percent stated that their response started when the responding unit was notified of the call. However, almost 23% defined response interval as starting when dispatch received the call, and 11% defined it as starting with the initial 911 call. A factor that affected response intervals was routing of the 911 call. Less than 6% of agencies had only 1-call routing.

CONCLUSION

Agencies use different time points as the start and end of their response interval, which makes comparison of results directly related to response intervals across agencies or regions difficult. To maintain an appropriate standard of prehospital emergency medical care throughout the state, the use of consistent standard terminology defining response intervals will help reach that goal.

Critical care transport: outcome evaluation after interfacility transfer and hospitalization

STUDY OBJECTIVE

To test the hypothesis that interfacility transfer is not associated with increased mortality, duration of stay, or readmission within 7 days.

METHODS

We matched 3,298 patients who were hospitalized for chest pain or related complaints in Kaiser Permanente medical centers after transfer from the emergency department of a nonplan hospital (transported patients) with 3,298 patients of the same gender and age (+/-5 years) and with the same principal diagnosis who were hospitalized within 6 months without transfer in the same Kaiser Permanente medical center (directly admitted patients). Patients were compared in terms of outcome measures: in-hospital deaths, continued care in another facility, readmission within 7 days, in-patient length of stay (LOS), and LOS in special care units.

RESULTS

The adjusted odds ratios for in-hospital mortality and readmission within 7 days were 1.0 (95% confidence interval,.8 to 1.4) and.9 (95% confidence interval,.7 to 1.2), respectively. The adjusted mean difference in LOS was -.1 days (95% confidence interval, -.2 to.1). Transported and directly admitted cardiac patients were also compared for all examined outcome measures at each of 10 medical centers. At a few medical centers, we observed significant difference in LOS, special care LOS, and continued care in another facility. However, all these differences were small, and most were probably random errors.

CONCLUSION

Conservative patient selection criteria, pretransfer stabilization, and the use of appropriate equipment and medical personnel have resulted in the interfacility transfer program's achieving its goal of transferring high-risk patients without adverse impact on clinical outcomes or resource use.

Effectiveness of ambulance paramedics versus ambulance technicians in managing out of hospital cardiac arrest

OBJECTIVE

To determine the effectiveness of extended trained ambulance personnel (paramedics) for the management of out of hospital cardiac arrest.

METHODS

A retrospective cohort study of patients who suffered a cardiac arrest between 1 January 1992 and 31 July 1994, and who were transported to their local accident and emergency (A&E) department. Data were collected on basic demography, operational time intervals, and ambulance crew status. Further clinical data were collected, and outcome measures included status on arrival at A&E, status on leaving A&E (hospital admission), and status on leaving hospital. The data were analysed using univariate and multivariate techniques.

RESULTS

Univariate analysis showed the likelihood of arriving in A&E with a return of spontaneous circulation was more than doubled among patients attended by a paramedic crew compared with those attended by technicians (relative risk = 2.48, 95% confidence interval 1.34 to 4.60). The likelihood of successful hospital admission was also significantly increased (RR = 1.92, 95% CI 1.13 to 3.27); however, beyond this point, further survival benefits appeared to be much smaller. Similar findings were revealed using multivariate analysis. Second level modelling revealed further possible differences between paramedic and technician crews according to type of incident. Patients successfully admitted to hospital who died before discharge remained severely disabled between admission and death.

CONCLUSIONS

There are marked short term survival advantages after cardiac arrest associated with paramedic care, but these probably diminish rapidly over time.