The effect of telemetry on urban prehospital cardiac care

Standing Orders for Field Intravenous Lines Do Not Shorten Prehospital Time in Trauma Patients

Study Objective:

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.

Design:

A prospective, randomized study was conducted.

Setting:

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.

Participants:

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

Results:

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).

Conclusion:

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.

Accuracy of rural EMS provider interpretation of three-lead ECG rhythm strips

OBJECTIVE

To measure the accuracy of lead II rhythm strip interpretations performed by advanced life support (ALS) emergency medical technicians (EMTs) in a rural emergency medical services (EMS) system.

METHODS

An electronic rhythm simulator was used to produce 24 three-lead electrocardiogram (ECG) rhythm strips. The rhythms were shown to 57 ALS EMTs participating in regularly scheduled continuing education classes. The participants were asked to identify the rhythms.

RESULTS

The three-lead ECG interpretations were generally accurate, although there was some difficulty in distinguishing between specific types of tachydysrhythmia and atrioventricular (AV) block. The overall accuracy of the rhythm interpretations was 79.2%, ranging from 45.6% (second-degree type II heart block) to 98.2% (sinus bradycardia). The sensitivity for specific tachydysrhythmias ranged from 68.4% (supraventricular tachycardia) to 86.0% (atrial fibrillation); the sensitivity for specific types of AV block ranged from 45.6% (second-degree, type II) to 71.9% (third-degree).

CONCLUSION

In this EMS system, ECG interpretations are generally accurate, with tachydysrhythmias and AV blocks being the source of most discrepancies.

Use of on-line medical command to randomize patients in a prehospital research study

OBJECTIVE

To describe the efficiency of using on-line medical command (OLMC) to conduct a prospective, randomized clinical trial addressing safety and patient enrollment.

DESIGN, SETTING, AND PARTICIPANTS

Prospective design using OLMC to randomize adult asthmatics into one of three treatment groups. After verifying inclusion and exclusion criteria, OLMC physicians removed a covering label on study sheets and ordered the treatment specified underneath the label that had been assigned in a random sequence.

RESULTS

A total of 204 patients were seen with dyspnea and wheezing during the three-month study. Of these, 68 (33%) were excluded from the study. Of the 136 (67%) patients who were eligible for study, 87 were enrolled (enrollment efficiency 64%), with 79 fully evaluable (evaluable efficiency 91%). The study safety was 100% because no enrolled patients met any exclusion criteria.

CONCLUSIONS

The design was random and prospective, with patient entry blinded, using paramedics to enroll patients and OLMC physicians as gatekeepers, thus ensuring appropriate patient eligibility and study-arm assignment. Use of OLMC physicians to perform prospective randomized studies is safe and efficient, and results in a high yield of evaluable patients.

Physician medical direction and advanced life support in the United States

OBJECTIVE

To determine the specialty training and responsibilities of urban U.S. emergency medical service (EMS) medical directors how these factors relate to the type of service involved (fire, hospital, private, municipal).

METHODS

A single mailed survey of training officers--field supervisors of 211 urban advanced life support (ALS) services in the United States. The survey also requested information about medications carried, approved procedures. and who set these standards. Respondents also rated the EMS medical director's involvement in various activities (quality assurance, administrative, executive, run reviews, and in-service/education).

RESULTS

Eighty-five percent (n = 179) of the forms were returned. with 165 (78%) usable. The physician EMS medical directors were primarily trained in emergency medicine (77%) and were paiid (75%) for EMS responsibilities. The number of medications carried and the number of approved procedures were not related to either the number of hours the physicians commit weekly to the EMS service or their degree of involvement in ALS activities. The physician EMS medical directors were most often involved in quality assurance and education and were less likely to devote time to executive or other administrative functions of ALS units, with the exception of fire-based EMS physician medical directors, who contributed significantly to executive and administrative functions (p < 0.05). Overall practice standards were established by the medical director (46%), the state department of health (24%), and local/regional health authorities (23%).

CONCLUSIONS

EMS training officers believe that urban ALS medical directors in the United States primarily provide quality assurance and educational support. With the exception of fire-based EMS systems. physicians appear to have limited involvement in other EMS administrative and executive functions.

Comparison of interventions in prehospital care by standing orders versus interventions ordered by direct [on-line] medical command

OBJECTIVE

The aim of this study was to compare the patient care measures provided by paramedics according to standing orders versus measures ordered by direct [on-line] medical command in order to determine the types and frequency of medical command orders.

DESIGN

Prospective identification of patient care measures done as part of a prehospital quality assurance program.

SETTING

An urban paramedic service in the northeast United States with direct medical command from three local hospitals.

PARTICIPANTS

One thousand eight paramedic reports from October 1992 through March 1993.

INTERVENTIONS

All patient care interventions recorded as done by standing orders or by direct medical command orders. Errors in patient care were determined by the same criteria as in the prior two studies of the same system.

RESULTS

Direct medical command gave orders in 143/1,008 (14.2%) cases. Paramedics performed 2,453/2,624 (93.5%) of the total patient care interventions using standing orders. In 61 cases (6.1%), medical command ordered a potentially beneficial intervention not specified by standing orders or not done by the paramedic. 21/171 (12.3%) command orders were for additional doses of epinephrine or atropine in cardiac arrest cases (where the initial doses had been given under standing orders), and 59/171 (34.5%) were for interventions already mandated or permitted by standing orders. The paramedic error rate was 0.6%, and the medical command error rate was 1.8% (unchanged form the prior study of the same standing-orders system).

CONCLUSION

Direct medical command gave orders in 14% of cases in this standing-orders system, but 35% of command orders only reiterated the standing orders. More selective and reduced uses of on-line command could be done in this system with no change in the types or numbers of patient care interventions performed.

Decrease in medical command errors with use of a "standing orders" protocol system

The purpose of this study was to determine the physician medical command error rates and paramedic error rates after implementation of a "standing orders" protocol system for medical command. These patient-care error rates were compared with the previously reported rates for a "required call-in" medical command system (Ann Emerg Med 1992; 21(4):347-350). A secondary aim of the study was to determine if the on-scene time interval was increased by the standing orders system. Prospectively conducted audit of prehospital advanced life support (ALS) trip sheets was made at an urban ALS paramedic service with on-line physician medical command from three local hospitals. All ALS run sheets from the start time of the standing orders system (April 1, 1991) for a 1-year period ending on March 30, 1992 were reviewed as part of an ongoing quality assurance program. Cases were identified as nonjustifiably deviating from regional emergency medical services (EMS) protocols as judged by agreement of three physician reviewers (the same methodology as a previously reported command error study in the same ALS system). Medical command and paramedic errors were identified from the prehospital ALS run sheets and categorized. Two thousand one ALS runs were reviewed; 24 physician errors (1.2% of the 1,928 "command" runs) and eight paramedic errors (0.4% of runs) were identified. The physician error rate was decreased from the 2.6% rate in the previous study (P < .0001 by chi 2 analysis). The on-scene time interval did not increase with the "standing orders" system.(ABSTRACT TRUNCATED AT 250 WORDS)

Prehospital misidentification of tachydysrhythmias: a report of five cases

Identification and treatment of tachydysrhythmias is an important element of prehospital care. Five cases of prehospital misidentification of tachydysrhythmias are presented to highlight the challenges and pitfalls of field management. The literature is reviewed and discussed in light of new therapies and technology. Guidelines for patient subgroups potentially benefitting from on-line medical control and biotelemetry are explored.

Cellular telephone transmission of 12-lead electrocardiograms from ambulance to hospital

Currently, only single-lead, serial telemetry rhythm strips can be transmitted from ambulances. Triage of patients with chest pain and administration of thrombolytic therapy in ambulances is limited by the lack of specific electrocardiographic (ECG) diagnosis. A new technique is described using cellular telephone transmission of simultaneous 12-lead ECGs from ambulance to hospital to overcome this limitation. A portable 12-lead ECG installed in an ambulance was connected via modern link to a cellular telephone and digitized ECG information was transmitted to an ECG device in the hospital emergency room. Paramedics in the field placed adhesive patch electrodes and attached ECG wires. Field ECGs from 23 patients were compared with corresponding transmitted ECGs. There were no differences in heart rate, PR interval, QRS duration, QT interval or R- and T-wave axes. Baseline and transmitted ECGs had identical morphologic characteristics. Differences in R-wave amplitude in 5 transmitted tracings compared with hospital-recorded ECGs resulted in computer diagnosis of left ventricular hypertrophy by voltage, possibly due to differences in patient position. Twelve-lead ECGs can be easily transmitted from a moving ambulance using cellular telephones. This allows diagnosis before hospital arrival, improves prehospital triage of patients and may facilitate prehospital therapy with lidocaine or streptokinase. In addition, the cellular telephone link can convey both verbal and digitized information and thus improve on current telemetry systems.