To determine the clinical efficacy, patient volume, and program costs that justify pediatric intraosseous (IO) infusion as a routine skill for the treatment of patients with cardiac arrest in a prehospital system.

A decision analytic model was constructed to include patient outcomes and costs to society. Critical variables for the analysis were: 1) time to vascular access; 2) success of vascular access; 3) clinical efficacy (i.e., the percentage of lives saved by early vascular access); 4) number of patients requiring IO annually; and 5) the cost of an IO program. Program costs included training and equipment expenses. Sensitivity analysis, which repeatedly evaluates the model using different values for the critical variables, identified those values at which IO would be cost-effective.

With an estimated 80% success rate for IO access within five minutes, the cost-per-life-saved would be [US] $161,000. This cost-effectiveness ratio assumed annual program expenses of $2,000 and one patient per year needing IO. The cost-effectiveness ratio also required a clinical efficacy of 2% for vascular access. To prove that the clinical efficacy of vascular access is in fact 2%, epidemiologic studies would require a sample of nearly 9,000 patients.

This analysis suggests IO probably is cost-effective given a clinical efficacy above 2%. While the true efficacy may be below this value, clinical studies are unlikely to have sufficient size to prove it. Therefore, emergency medical services (EMS) medical directors must make the decision to utilize IO based on their own beliefs about its clinical efficacy. Further, it must be considered in the context of other prehospital programs which may be more cost-effective. Such analyses permit establishment of rational priorities to rank programs in prehospital systems.

Emergency cardiopulmonary resuscitation (CPR) instruction via telephone (ETCPR) is cost-effective compared to prehospital, emergency medical technician (EMT)/paramedic treatment alone of witnessed, ventricular fibrillation (VF) in adult patients.

A total of 118 patients, age >18 years, with prehospital, witnessed ventricular fibrillation were studied. Patient data were extracted from hospital records, monitor-defibrillator recordings, paramedic reports, dispatching records, and telephone interviews with bystanders. No ETCPR was available during this period. The costs of ETCPR implementation were estimated retrospectively. Marginal cost of the paramedic service attributable to treatment of VF was calculated from fire department records. Years-of-life saved were estimated from age, gender, and race matched norms.

Of the 53 patients receiving bystander CPR (BCPR), 14 (26%) survived to hospital discharge versus 4/65 patients (6%) lacking BCPR, These groups did not differ significantly (p>.05) in age, EMS response times, or time from collapse to defibrillation. The mean time interval from collapse to CPR was significantly less for patients with BCPR (1.8 min) than for patients without BCPR (7.1 min). Had all patients received BCPR and survived at the rate of 0.26, 13 additional patients would have survived to hospital discharge. The cost per year-of-life saved by the EMS system with ETCPR would have been [US]$2,834 versus $4,881 without ETCPR. The cost per additional year-of-life saved by ETCPR was estimated to be $560 in patients experiencing out-of-hospital ventricular fibrillation.

The use of ETCPR instruction of callers by 9-1-1 dispatchers potentially is a cost-effective addition to a two-tier, EMS system for treatment of prehospital ventricular fibrillation.

Emergency medical technicians (EMTs) find that the death of patients in their care is stressful.

Random sample of certified EMTs in one state (Levels I–IV).

A blinded, self-administered survey was sent to a random sample of 2,500 EMTs. Demographic data obtained were: level of training; hours worked each month; population of area served; age; gender; number of deaths per year; training for coping prehospital deaths; and availability of protocols and on-line medical advice for out-of-hospital deaths. A five-point, Likert scale was used to rate the frequency of perceived stress experienced by EMTs in specific situations and the routine practice for notification of survivors. Univariable analysis was performed using Spearman's Rank correlation, Kruskal-Wallis test, and Mann-Whitney U-test. Multivariable correlations were performed using forward and backward step-wise logistic regression analysis. A significance level of 0.05 was used throughout.

There were 654 respondents with a mean age of 35.5±8.3 yr; 83% were men. Their highest level of training was: 4% EMT-I, 43% EMT-II, 18% EMT-III, 33% EMT-IV. They saw an average of 9.6 deaths/year and spent an average of 20±17 minutes with survivors. 62 % found treatment of a patient that was dying or died in their care was commonly a stressful experience. Factors that made notification of the family about the prehospital death emotionally difficult included: fewer hours worked/month; working in a smaller community; lower level of EMT training; female gender; and fewer deaths seen during the previous year. The same factors were associated with general emotional difficulty in treatment of a patient who died during prehospital care. Online [direct] medical direction by physicians was common (73%), but did not lessen the difficulty of notification. It did reduce the emotional difficulty for specific clinical situations. Written protocols for not attempting resuscitation were common (66%), but only 44% had protocols for termination of resuscitation. Resuscitation of the clearly dead for the benefit of the family (10%) or for the EMT (5%) was practiced infrequently. Most (67%) respondents had some formal training in dealing with death and the dying patient. Such training did not correlate with less difficulty in notification of survivors or in coping with the deaths of patients in their care.

EMTs perceive they have emotional difficulty when prehospital deaths occur and survivors must be notified. Less experience and a lower level of EMT training correlate with more difficulty in coping with patient death. Protocols and on-line [direct] medical control can provide support for the EMT in coping with out-of-hospital deaths. Most notification of survivors is handled by EMTs with formal training to cope with patients that are dying or who die during prehospital care.

Paramedics accurately estimate the closest trauma hospital for ground transport.

Ground ambulance scene transports of trauma system patients to six participating trauma hospitals in Multnomah County, Oregon from 1 January 1986 to 1 January 1987 were studied. Transports involving multiple patients or pediatric patients were excluded.

A retrospective analysis was performed on consecutive patient transports to be taken to the closest trauma hospital as required by protocol. The availability of each hospital to receive trauma patients was monitored continuously by a central communications facility. Paramedics were provided hospital availability data at the time of patient system entry. When several hospitals were available, the paramedics were required by protocol to select the “closest” hospital. Subsequently, the vector distance from the trauma site to each of the available hospitals was measured using a grid map. This method was validated by odometer measurement (r2 = 0.924). Chisquare analysis was used to analyze hospital bypasses to specific hospitals.

Of the 1193 eligible patients entered into the trauma system, 160 (13%; 95% CI = 11–15%) transports bypassed the closest available hospital for a receiving hospital ≥1 mile more distant. There were 11 (1%; 0–2%) patients transported to a hospital more than five miles more distant. Of the 132 patients with a trauma score (TS) <12, 15 (11%; 6–18%) were taken to a hospital one mile or further beyond the closest hospital. None (0%; 0–2%) were transported more than five miles past the closest hospital. Of the six hospitals, three were bypassed more than one mile significantly more often then they received bypass patients. One hospital received such patients four times more than it was bypassed (p <.001).

While paramedics generally can identify the closest hospital for trauma patient transport, some systematic hospital bypass errors occur. If a community wants assurance of an equitable patient distribution among participating trauma hospitals and assignment of the closest geographic hospital for injured patients, then map vector distance determination to identify the closest available hospital should supplement paramedic dispatching.

Emergency physician interpretation of prehospital, paramedic-acquired, electrocardiograms (ECG) is accurate judged by comparison with that of a reference cardiologist.

Twelve-lead ECGs were obtained by paramedics in the field from 150 patients with acute chest pain. The ECGs were transmitted by cellular telephone to a central location. Each ECG was assessed for evidence of acute myocardial infarction (AMI) by: 1) a third-year, emergency medicine resident (EMP-R); 2) a residency-trained, board-certified, emergency physician (EMP-RT); 3) an emergency physician board certified under the practice option (EMP-PT); and 4) a board-certified cardiologist. Agreement between each emergency physician and the cardiologist was assessed by the kappa statistic. Hospital records were reviewed for final diagnosis of each patient.

Sixteen of 150 (10.7%) patients received a hospital discharge diagnosis of AMI. Sensitivity of physician interpretation ranged from 0.31 to 0.56. All physicians achieved specificity of 0.99. False-positive rates for the physicians ranged from 0.18–0.29. The mean positive predictive value for the four physicians was 0.77±0.05; the mean negative predictive value was 0.94±0.01. The total agreements between the EMP-R, EMP-RT, and EMP-PT and the cardiologists were 0.97, 0.96, and 0.97, respectively. Kappa values for agreement between the emergency physicians and the cardiologist ranged from 0.65–0.79.

Residency-trained or board-certified emergency physician interpretations of prehospital, paramedic-acquired 12-lead ECGs show a high degree of agreement with reference cardiologist interpretations.

To determine if intravenous (IV) glucose boluses cause significant alterations of serum potassium ([K+]) levels.

A prospective, descriptive study of patients ≥18 years of age presenting with altered levels of consciousness (ALOC) to paramedics in the prehospital setting or to the emergency department (ED) of a community teaching hospital and who received 50% Dextrose (D50) intravenously (IV). At presentation, a blood sample (PRE) was obtained prior to D50 therapy. For patients treated by paramedics, a second blood sample (POST) was obtained upon arrival at the ED. For patients who initially were seen in the ED, the POST sample was obtained one hour after D50 therapy. Both samples were analyzed to determine [K+] and glucose levels.

Over a seven-month period, 40 patients met study criteria. The average age was 46±20 years. Sixty percent of patients (24/40) had PRE blood sugars (BS) <80 mg/dl (mean PRE BS = 37±12 mg/dl; mean POST BS = 140±45 mg/dl) and 40% (16/40) had a PRE BS >80 mg/dl, (mean PRE BS = 241±255 mg/dl; mean POST BS = 274±237 mg/dl). The mean PRE [K+] was 4.1±0.8 mEq/L and the mean POST [K+] was 4.2±0.7 mEq/L. Forty-two percent of patients (17/40) had a <5% change in [K+], 33% (13/40) had a >5% increase in [K+], and 25% (10/40) had a >5% decrease in [K+]. Ten percent of patients (4/40) had a >20% increase in [K+], and 3% (1/40) had a ≥20% decrease in [K+]. No patient was treated for symptoms of either hyperkalemia or hypokalemia.

Boluses of IV glucose produce unpredictable changes in [K+]. The majority of these changes probably are insignificant clinically.

This study is an evaluation of the ability of medically trained and controlled emergency medical dispatchers to use telephone triage techniques to direct the appropriate prehospital unit to an emergency scene.

Emergency dispatchers, educated in a formal emergency medical dispatch program, were assigned one of four triage priorities to incoming 9-1-1 calls. The actual field management delivered for each patient was compared with the dispatcher's triage to determine the appropriateness of triage.

A total of 1,045 consecutive calls were reviewed with 74.4% sorted as needing advanced life support (ALS) units on scene; 65.3% (95% CI, 61.9 to 68.6%) of these calls required ALS intervention. A total of 3.4% of the runs sorted to the non-ALS response groups were identified to have required ALS intervention. Comparing the need for ALS intervention, a significant difference was found between the triage groups.

Emergency medical dispatchers, using a formal system for telephone triage, are able to direct appropriate prehospital resources to the emergency scene.

No randomized, prospective studies have been conducted that examine how standing orders for establishing intravenous (IV) lines in trauma patients affect prehospital time. The purpose of this randomized, prospective study was to determine if standing orders for IV lines in the field shorten prehospital time.

A prospective, randomized study was conducted.

Trauma patients (n = 521) were randomized prospectively on an even-/odd-day basis over a one-year period from 1 April 1988 to 1 April 1989. Patients were sorted into an IV Standing Orders (SO) arm (n = 258) and a No Standing Orders (NO) arm (n = 263) in which On-Line [Direct] Medical Command (OLMC) was required before IV initiation.

Trauma patients, paramedics in a high-volume, urban, EMS system, and medical-command physicians on the trauma team at a Level 1 trauma center.

No significant differences were found in demographics, prehospital vital signs, mechanism of injury, or trauma severity scores between the two treatment arms. Scene times were similar for the two groups (IV SO = 11.4 minutes, and NO = 10.6 minutes, p = .1675) as was IV success rate (92% vs. 88%, p = .1729).

When compared to OLMC in this EMS system, IV standing orders did not affect scene time. This supports the concept that only spinal stabilization and airway management be performed at the scene and other ALS maneuvers (e.g., IVs) be performed in the ambulance, preferably en route to a Trauma Center. Since IV standing orders had no documented, adverse effects and led to focused, concise radio telemetry reports, this EMS system adopted their use on a permanent basis.

Circumstances surrounding the prehospital management of trauma patients may mask clinical signs of inadequate oxygenation. Pulse oximetry (PO) may influence airway management prior to helicopter transport by helping to identify patients with occult hypoxemia.

Patients were enrolled in a prospective study. Initially, the flight physician clinically decided how best to manage the patient's airway prior to helicopter transport. The patient's oxygenation saturation (O2at), was determined by PO. Then, the physician reassessed the initial airway management decision based on clinical assessment and knowledge of the O2Sat. All patients had an arterial blood gas (ABG) measurement taken after completion of transport.

Sixty patients were enrolled. Knowledge of the O2Sat, as determined by pulse oximetry, did not influence airway management. No patients with occult hypoxemia were identified.

The use of PO in the initial evaluation of trauma patients prior to helicopter transport did not influence the flight physician's initial management of the airway.

Helicopter emergency medical service (HEMS) systems typically are described in terms of their role in the care and transport of trauma victims, while their function(s) in the care of patients with medical illness goes unrecognized.

Review of 575 prehospital HEMS missions by a flight program located in rural, north-central Florida over a five-year period, was performed to define demographics regarding the nature of the call.

Scene responses for trauma victims comprised 63% of these missions, while patients with medical illnesses comprised 37%. The incidence of medical scene responses is significantly higher in this review than has been noted in previous reports.

1) In rural settings, patients with medical illnesses comprise a major share of prehospital HEMS responses; 2) HEMS flight crews should be competent in treatment of prehospital medical patients, and their protocols reflect the needs of these patients; and 3) EMS providers must be aware of the role of HEMS in the transport of the medical patient.