Integrated Medical-Surgical Care in Acute Coronary Artery Disease Adv. Cardio!., vo!. 15, pp. 9-24 (Karger, Basel 1975)
Mobile Emergency Care Units Implementation and Justification J. MICHAEL CRILEY, A. JAMES LEWIS and GAYLORD E. AILSHIE Department of Medicine, University of California, Los Angeles, School of Medicine, Los Angeles, and the Division of Cardiology, Harbor General Hospital, Torrance, Calif.
Introduction
1 Actual data is now available for Los Angeles County 1969-1970. There were 18,596 cardiovascular deaths, 91 Ufo attributed to ischemic heart disease. (Data derived from Los Angeles County Community Diagnosis Project, prepared by J. M. CHAPMAN and A. H. COULSON, 1973.)
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The high mortality in the prehospital phase of myocardial infarction [1-4] led to the concept of mobile coronary care units, initially in Moscow in 1957 [5], next in Belfast [6] and then in many cities in the United States [7]. The majority of these mobile units was staffed by physicians and nurses, and the American version of the vehicle rivalled the Apollo capsule in complexity and expense. Unfortunately, most communities were not and are not blessed with unlimited finances and unlimited professional personnel, so the mobile coronary care unit concept was rightfully challenged on financial as well as scientific grounds [8-10]. The financial climate in the scientific community took a turn for the worse in the late 1960s, and unlimited federal support of idealistic ventures rapidly became 'inoperative' . Over 3.5 Ofo of American population resided in Los Angeles County in 1969 and, based on national mortality statistics for cardiovascular disease (600,000 deaths per year), it was predicted that 20,000 residents of this metropolitan area would succumb to cardiovascular disease yearly 1 and probably over one-half of these deaths would occur outside the hospital. An unknown number, perhaps 5,000-10,000, would succumb with a 'heart too good to die', as a result of primary arrhythmic death, potentially reversible. Although it was not possible to put a dollar figure on the worth
CRILEY/LEWIS!AILSHIE
10
of a citizen wage-earner or parent whose life might have been spared by prehospital cardiac emergency care, it was difficult to deny a populous county this type of facility, particularly if it could be achieved at a reasonable cost. With this concept in mind, a pilot program was initiated in the southern portion of Los Angeles County in August, 1969. The goal was to provide mobile life support utilizing existing rescue personnel, vehicles and dispatch systems. At the same time, another pilot project was begun in the county by other investigators [11] utilizing nurse-specialists, a specialized cardiac vehicle and a physician-initiated dispatch system.
Materials and Methods
Existing Rescue Systems In the city and county of Los Angeles, the initial response to medical emergencies is the purview of the Fire Departments. The Los Angeles City Fire Department maintains a Rescue Ambulance Service, while the Los Angeles County Fire Department maintains a Fire Rescue Service which depends on contract (private) ambulances for patient transportation. There are over 70 incorporated cities within the county, some with rescue systems based on the city or county model, and some contracting for rescue service with the Los Angeles County Fire Department.
18 volunteer firemen, 12 from the county and 6 from the city fire departments, were accepted for the pilot training program in September, 1969. These men had an average of 2 years of experience in fire rescue work but no previous medical training beyond advanced first-aid. The pilot group received 180 h of classroom, laboratory and clinical instruction, followed by 6-9-month field service on a hospital-based vehicle (station wagon) accompanied by a cardiac care unit (CCU) nurse. Following implementation of state wide legislation [12] permitting Mobile Intensive Care Unit (MICU) paramedics to function without direct supervision, the subsequent 350 trainees received a training course consisting of over 400 h of classroom and laboratory instruction, direct clinical experience and field internship on a hospital-based training vehicle. The training period now lasts 5 months, 40 h!week. There are now two full-time training facilities operated by the Los Angeles County Paramedic Training Division with separate faculties at Harbor General Hospital and Los Angeles County-University of Southern California Medical Center, consisting of full-time nursing staffs supplemented by voluntary physician and
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Training Program
Mobile Emergency Care Units
11
technical staffs. The training encompasses scientific terminology, basic anatomy and physiology, over 50 h of cardiology, noncardiac emergencies including head trauma, fractures, burns and childbirth, and special techniques including cardiopulmonary resuscitation, venipuncture, intubation, intracardiac injections and inhalation therapy. The cardiac training consists of normal and abnormal physiology, myocardial infarction and its complications, cardiac pharmacology and a comprehensive arrhythmia course. The cost of training a county paramedic is $1,575, and the cost is borne by the county. Other fire departments requiring additional men to cover those in training expend approximately $ 6,000 in salaries for back-up personnel per man in training.
Legislation The Wedworth-Townsend Paramedic Act [12], drafted specifically to enable the MICU paramedics within the Los Angeles County to function without direct supervision, was signed into law in July, 1970. It was amended in June, 1971 (Assembly Bill 492), to encompass MICU paramedic programs throughout the state of California. Under the terms of the amended legislation, a certified MICU paramedic 2 may initiate cardiopulmonary resuscitation (CPR) and defibrillate a pulseless nonbreathing patient without professional supervision. Any therapy requiring parenteral (intramuscular, intravenous or intracardiac) medications requires authorization from a physician or certified MICU nurse 3 by radio or telephonic contact with a base station hospital. Six categories of drugs may be administered: antiarrhythmic, vagolytic, chronotropic, vasopressor, analgesic and alkalinizing agents, as well as intravenous glucose and electrolyte solutions. The physician and nurse are exempted from liability for civil damages resulting from instructions given 'in good faith', as are the paramedics under separate legislation [13].
Operation of MICU Teams
2 Certified by the appropriate county official, i.e. Director of Health Services, under provision of the Wedworth-Townsend Paramedic Act. 3 As for footnote 2.
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The initial 3 paramedic squads trained at Harbor General Hospital provided 3 model configurations which provided prototypes for the subsequent 46 squads trained in the next 4 years. Although each team received similar training, there were major differences in vehicles and modes of operation (table I). At the present time (January, 1974) 40~/o of the county has minimal paramedic coverage and approximately 550 additional paramedics will be needed for complete geographic coverage.
CRILEy!LEWIS/AILSHIE
12
Table I. Paramedic team configurations
MICUteam
Location
Vehicle
Comments
Station 59 LACo.FD
fire station on hospital grounds
originally a station wagon, later replaced by a high-top van (fig. 1)
hospital-based training unit; paramedics maintain close contact with physicians and nurses; paramedics work in CCU and emergency room between calls; requires private or contract ambulance for patient transport
Station 36 LA Co. FD, prototype for 22 other county rescue squads
fire station 1mifrom hospital
utility truck (fig. 2)
upgraded Fire Rescue Service, requiring no additional manpower or vehicles; unit responds to all emergency calls and fires; unit carries equipment for extrication of victims from vehicular accidents, burning buildings, cliff rescues, etc.; utilizes private or contract ambulance for patient transport
Station 53 LAFD, prototype for 4 other city rescue ambulances
fire station 10 mi from hospital
rescue ambulance (fig. 3)
upgraded Rescue Ambulance Service, requiring no additional manpower or vehicles; unit responds to all emergency calls; transports patient - not dependent on private ambulances
MICU = mobile intensive care unit; LA Co. FD = Los Angeles County Fire Department; CCU = coronary care unit.
Squad 59 is a Los Angeles County Rescue Unit operating from a small fire station on the Harbor General Hospital grounds, which originally utilized a station wagon and currently a high-top van, carrying battery-powered portable equipment and drugs. The 6 men work in 2-man shifts, 24 h on, 48 h off. They sleep and eat on the hospital grounds, and spend time between calls in the CCU and emergency room. These men wear white coats, are identified as 'MICU paramedics' with name-badges, and are permitted to participate in many clinical activities in the hospital. They are permitted to assist the CCU nurses, record electrocardiograms (ECG), initiate intravenous infusions, perform CPR and countershock therapy, and the like.
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Training Vehicle - Squad 59 (fig. 1)
Mobile Emergency Care Units
13
Fig. 1. Hospital-based training unit, located at Fire Station 59 on the Harbor General Hospital campus. This high-topped van functions as a training unit for paramedics completing the field portion of their 5-months training. They are supervised during this phase of their training by experienced paramedics. The portable cardiac resuscitative equipment is displayed in front of the open doors.
This unit is used as a trammg facility for paramedic trainees as well as experienced MICU paramedics for 'refresher' training. Squad 59 responds to all rescue calls received from the fire rescue dispatch operation, and the men can be reached by 'hot-line' telephones in the CCU and fire station, by hospital pages or via portable hand-carried radios. Their rescue response area consists of 59 mi 2 and overlaps the Squad 36 (see below). They may perform as a back-up unit for Squad 36.
Squad 36 is a Los Angeles County rescue unit based at a Carson fire station 1 mi from Harbor General Hospital and has a response area of 38 mi2 • The 6 men work in 2-man shifts, sleep and eat at the fire station, and wear fire department uniforms. They respond to all fires as rescue paramedics, as well as to all rescue calls relayed by the dispatch center. Their vehicle is a standard fire department utility truck, equipped with cliff rescue gear, extrication tools, etc., in addition to the portable MICU equipment. Neither Squad 59 nor Squad 36 transports patients to the hospital. A private or contract ambulance is called and, if indicated by the emergency or requested by the base-station physician, a paramedic with portable equipment accompanies the patient in the ambulance to the hospital.
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Fire Rescue Unit - Squad 36 (fig. 2)
14
CRILEY /LEWIS/AILSHIE
a
I,
. .
:
.ro .• ,
.
,
Fig. 2. a Utility truck of the type used by 23 fire rescue squads in the Los Angeles County Fire Departments. b The resuscitative equipment is stored inside a side panel on the truck.
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b
Mobile Emergency Care Units
15
Fig. 3. Interior view of a Los Angeles City Rescue Ambulance which is typical of the 5 rescue ambulances maintained by the City Fire Department. The numbered items are: (1) bedboards for resuscitation; (2) battery-powered aspirator; (3) portable battery-powered electrocardiogram (ECG) oscilloscope; (4) portable battery-powered defibrillator; (5) portable transceiver for radio communications with base station; (6) cardiac drug box, and (7) first-aid equipment.
This unit is a Los Angeles City Fire Department unit located in the WilmingtonSan Pedro area, about 10 mi from Harbor General Hospital. It has a response area of 30 mi2 • The men wear fire department uniforms and they eat and sleep at the fire station. They respond to all emergency calls from the dispatcher and transport the patient to the hospital in their vehicle. Subsequent to 1972, the city fire department has employed civilian (nonfireman) paramedics.
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Rescue Ambulance 53 (fig. 3)
16
CRILEY /LEWIS/AILSHIE
Table lIa. MICU portable equipment Approximate cost, $ 1. Electrocardiogram (ECO) oscilloscope, battery-powered 950.00 2. Portable transceiver with ECO amplifier and modulator 3,200.00 3. D.C. defibrillator. battery-powered 1,750.00 4. Inhalation equipment Ambulance bag Elder valve Oxygen Airways - oropharyngeal and esophageal 5. Aspirator, battery-powered 175.00 6. Drugs Vasoactive: norepinephrine, metaraminol, epinephrine, isosorbide dinitrate, glyceryl trinitrate, isoproterenol Chronotropic: isoproterenol Vagolytic agents: atropine Antiarrhythmic: lidocaine Intravenous solutions: 5 % dextrose, normal saline, Ringer's lactate, dextran Analgesics: morphine, pentazocine (Talwin®) Antidotes: 50 % glucose, nalline Electrolyte concentrates: calcium chloride, sodium bicarbonate Miscellaneous: forosemide, benedryl, syrup of ipecac Sedatives, anticonvulsants: phenobarbital, diazepam (Valium®) 7. Miscellaneous Stethoscope Sphygmomanometer Splints - vacuum type Obstetrical equipment
Table lIb. Base-station (hospital) equipment Approximate cost, $ 2,300.00 4,000.00
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1. Base-station transceiver with duplexer and antenna 2. Base station console Cassette tape-recorder Strip chart recorder Demodulator Oscilloscope
Mobile Emergency Care Units
17
Fig. 4. Base station console at Harbor General Hospital consisting of transceiver, ECG demodulator, ECG oscilloscope, strip chart recorder and cassette tape-recorder for recording voice and ECG transmission. A coronary care unit (CCU) intern and certified mobile intensive care unit (MICU) nurse are communicating with the MICU, and a permanent record is made of each call by use of recorded data on the cassette tape.
Emergency Equipment All paramedic fire rescue squads and rescue ambulances carry essentially identical portable equipment (table II, fig. 1-3) costing approximately $ 6,000, consisting of cardiac and non-cardiac instrumentation and medications. This equipment can be hand-carried into the home, factory or scene of an accident. A major advance in airway maintenance has resulted from the use of the Gordon-Don Michael esophageal airway [14], an inexpensive device which can be inserted in less than 30 sec after brief training.
For these 3 prototype units and three subsequent units the base station at Harbor General Hospital in Torrance, California, is a 700-bed teaching hospital which functions as the southern campus of the University of California, Los Angeles (UCLA), Medical School. The CCU was chosen as the operational base because of
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Base Station
CRILEY/LEWIS/AILSHIE
18
_ L! ~ t '. t
r
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.·1
t
After def,brillalion
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30 sec later
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the immediate 24-hour availability of a physician and certified MICU nurse. The emergency room is consulted or alerted by telephone by the CCU staff in the event of burns, trauma or other emergencies requiring additional expertise. 18 subsequent base-station hospitals have entered paramedic-supervisory operation, the majority being private, non university affiliated community hospitals without house staff coverage. Some of these community hospitals utilize the emergency room rather than the CCU as a base-station facility, and must rely on the MICU nurses for the majority of the radio-telemetric supervision of the paramedic teams. The base-station console (table II, fig.4) consists of a transceiver, ECG demodulator oscilloscope, strip chart recorder and cassette tape-recorder. A back-up 'hotline' telephone system may be used for voice or ECG transmission in case of technical difficulties with radio (a rare occurrence). Each incoming call from a paramedic team
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Fig. 5. Resuscitation of patient (C. D., aged 62 years; 6.3. 1971) with ventricular fibrillation (VF) due to acute myocardial infarction. VF (top panel) was present when MICU arrived. Defibrillation resulted in complete heart block (second panel) which spontaneously converted to normal sinus rhythm.
Mobile Emergency Care Units
19
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NaHC0 3 and atropine
A fler 400 W shock, lidocaine
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r((((t(rrtr( I I I
48 h later
1
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3 min later
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is received by an intern or resident physician and recorded on cassette tape for later review by a staff physician. The ECG is received as a frequency-modulated (FM) tone signal which is recorded on cassette tape and can be displayed on the oscilloscope and recorded on the strip chart recorder. The cassette tape can be replayed to review both the voice and electrocardiographic data at any future time. Only on rare occasions is the telemetered ECG not of diagnostic quality for the interpretation of arrhythmias. A common problem is distortion of the ST segment, caused by lowfrequency filtering.
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Fig. 6. Resuscitation of patient (M. T., aged 16 years; 16.4. 1971) with VF secondary to aspiration. VF was present when MICU arrived (top panel). Following defibrillation, complete heart block occurred with ventricular asystole (second panel); idioventricular rhythm then developed with multiple premature ventricular contractions (PVC) (third and fourth panels). Ventricular flutter ensued (fifth panel) and was not responsive to D.C. countershock, but was converted to a supraventricular tachycardia following lidocaine administration. At this time, a blood pressure of 180/ 40 mm Hg was obtained. CPR = cardiopulmonary resuscitation.
CRILEyjLEWIS!AILSHIE
20
Typical Operation A patient in distress may dial the fire rescue or rescue ambulance dispatch number directly, state the nature of the complaint and give his name, age and address. As the dispatcher does not attempt to categorize or screen calls, delays in dispatching paramedics to the scene are kept to a minimum. The average response time from the paramedics' receipt of the call from the dispatcher to arrival at the scene is 5.6 min. Upon arrival at the scene, the paramedics briefly question and examine the patient and institute any necessary emergency resuscitative procedures. Electrocardiographic leads (self-adhering chest electrodes) are placed on the patient if indicated, and contact is made by radio with the physician in the CCU. The physician directs the course of treatment, such as starting intravenous infusion, drugs or possibly countershock. As noted above, the paramedic may employ CPR and countershock before contacting the physician in dealing with pulseless, nonbreathing patients (fig. 5, 6). If transportation to the hospital is required, a private (contract) ambulance is dispatched to the scene (if not there already), and that ambulance is upgraded to a MICU by the addition of one or more paramedics and their specialized portable equipment. Before transport, every attempt is made to stabilize the condition of the patient by institution of an adequate airway, countershock therapy, the administration of antiarrhythmic drugs and sodium bicarbonate and the institution of antihypotensive medications as indicated. When stabilization has been reached (or reasonable attempts to bring it about have failed) the patient is transported to the hospital. Rapid transport with red light and siren (Code 3) is avoided when the patient has stable vital signs. If the patient has a cardiac problem, he is taken directly from the ambulance to the CCU, accompanied by the paramedics and their portable equipment. During transport, constant contact with the base-station physician is maintained. Most patients are transported to Harbor General Hospital, but they may request to be taken to a private hospital, in which case the base-station physician calls the hospital to inform the physician or nurse on duty in the emergency room. If possible, the patient's private physician is contacted also. In cases of obvious cardiac distress (i.e., suspected myocardial infarction, significant arrhythmias, hypotension, etc.) a direct admission to the CCU in the outside hospital is arranged. No additional charge (above that of the private ambulance fees) is rendered the patient by the Los Angeles County Fire Rescue Paramedic Service.
The rapidly expanding program now comprises 49 MICU paramedic units serving 19 base-station hospitals, and covers approximately 40010 of Los Angeles County and its incorporated cities with advanced rescue capabilities. As of December, 1973, 50,909 rescue calls were made, of which 9,310 (18.2010) had primary or significant cardiac problems. The
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Results
Mobile Emergency Care Units
21
cost of implementing this enhanced rescue service, including training costs, portable MICU equipment (not including expendable supplies) and basestation equipment has been slightly over $1,000,000 - or approximately $0.36 per citizen covered by paramedic service - or $19 per rescue call. This latter figure will decrease as the number of calls increases, since many of the MICU paramedic squads have less than 6 months of service. Detailed statistics on the nature of cardiac problems encountered by all of the paramedic units are not available, but the following data represent statistics derived from the paramedic rescue squads serving the base-station at Harbor General Hospital.
Resuscitation from Ventricular Fibrillation In 3 ~ years, 246 patients with ventricular fibrillation were encountered in the field, and 70 (280/0) could be restored to a supraventricular rhythm at the time of transport to the hospital. 20 of these patients (8 % of those in ventricular fibrillation) survived to leave the hospital. A detailed analysis was made of the first 12 long-term survivors [15] which occurred in the first 30 months of paramedic operation at Harbor General Hospital. During that time 4,749 patients were treated by the paramedics, and a significant cardiac problem (cardiac arrest, myocardial infarction, congestive failure, angina, arrhythmia, etc.) was encountered in 902 patients (190/0). Ventricular fibrillation outside the hospital was documented in 137 (fig. 7), or 150/0, of the patients with significant cardiac problems. In 44 (32 Ofo) of the patients with ventricular fibrillation, field resuscitation was successful in restoring a supraventricular rhythm which was maintained up to the time of arrival at the hospital. Of the 44 successful resuscitations 32 died in the hospital: 15 in the first hour, 10 within 72 h and the remainder in the first 7 days of hospitalization. 12, or 8.80/0, of the patients with ventricular fibrillation survived to leave the hospital. Their subsequent courses are displayed graphically in figure 8.
The prehospital incidence of ventricular arrhythmias other than ventricular fibrillation among cardiac patients has been 32 % premature
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Other Arrhythmias
CRILEY (LEWIS(AILSHIE
22
I
L
..
_U"'_' " - - - . - - " ' - '
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Fig. 7. The fate of 137 patients found in ventricular fibrillation (VF) in the field in the first 30 months of parademic operation. There were 12 long-term survivors.
III
IV
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Fig. 8. Symptomatic classification (according to New York Heart Association [NYHA]) in 10 patients with coronary heart disease before resuscitation from ventricular fibrillation (VF), and following release from the hospital.
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L _ _ _ _ __
Mobile Emergency Care Units
23
ventricular contractions and 12010 ventricular tachycardia. These arrhythmias were treated by intravenous lidocaine and countershock, if indicated; no deaths occurred during the paramedic run in these patients.
Myocardial Infarction Major complications encountered in patients with myocardial infarction entering the CCU via the MICU consisted of: major arrhythmias, 30010; cardiogenic shock, 90/0; pulmonary edema, 26010; death, 11010. There was no significant difference in incidence of these complications in MICU patients as compared to patients with myocardial infarction admitted to the CCU via the usual channels. It was anticipated that MICU patients would actually have higher morbidity and mortality, since they had called for emergency aid rather than entering the hospital by conventional means. When the total duration of symptoms prior to admission to the CCU was less than 2 h, 53 010 had no complications, and this percentage fell to 37 0/0 (p 0.001) if CCU arrival was delayed from 2 to 12 h.
Mobile Emergency Care Units Implementation and Justification J. MICHAEL CRILEY, A. JAMES LEWIS and GAYLORD E. AILSHIE Department of Medicine, University of California, Los Angeles, School of Medicine, Los Angeles, and the Division of Cardiology, Harbor General Hospital, Torrance, Calif.
Introduction
1 Actual data is now available for Los Angeles County 1969-1970. There were 18,596 cardiovascular deaths, 91 Ufo attributed to ischemic heart disease. (Data derived from Los Angeles County Community Diagnosis Project, prepared by J. M. CHAPMAN and A. H. COULSON, 1973.)
Downloaded by: University of Cambridge 131.111.164.128 - 1/31/2019 7:41:48 PM
The high mortality in the prehospital phase of myocardial infarction [1-4] led to the concept of mobile coronary care units, initially in Moscow in 1957 [5], next in Belfast [6] and then in many cities in the United States [7]. The majority of these mobile units was staffed by physicians and nurses, and the American version of the vehicle rivalled the Apollo capsule in complexity and expense. Unfortunately, most communities were not and are not blessed with unlimited finances and unlimited professional personnel, so the mobile coronary care unit concept was rightfully challenged on financial as well as scientific grounds [8-10]. The financial climate in the scientific community took a turn for the worse in the late 1960s, and unlimited federal support of idealistic ventures rapidly became 'inoperative' . Over 3.5 Ofo of American population resided in Los Angeles County in 1969 and, based on national mortality statistics for cardiovascular disease (600,000 deaths per year), it was predicted that 20,000 residents of this metropolitan area would succumb to cardiovascular disease yearly 1 and probably over one-half of these deaths would occur outside the hospital. An unknown number, perhaps 5,000-10,000, would succumb with a 'heart too good to die', as a result of primary arrhythmic death, potentially reversible. Although it was not possible to put a dollar figure on the worth
CRILEY/LEWIS!AILSHIE
10
of a citizen wage-earner or parent whose life might have been spared by prehospital cardiac emergency care, it was difficult to deny a populous county this type of facility, particularly if it could be achieved at a reasonable cost. With this concept in mind, a pilot program was initiated in the southern portion of Los Angeles County in August, 1969. The goal was to provide mobile life support utilizing existing rescue personnel, vehicles and dispatch systems. At the same time, another pilot project was begun in the county by other investigators [11] utilizing nurse-specialists, a specialized cardiac vehicle and a physician-initiated dispatch system.
Materials and Methods
Existing Rescue Systems In the city and county of Los Angeles, the initial response to medical emergencies is the purview of the Fire Departments. The Los Angeles City Fire Department maintains a Rescue Ambulance Service, while the Los Angeles County Fire Department maintains a Fire Rescue Service which depends on contract (private) ambulances for patient transportation. There are over 70 incorporated cities within the county, some with rescue systems based on the city or county model, and some contracting for rescue service with the Los Angeles County Fire Department.
18 volunteer firemen, 12 from the county and 6 from the city fire departments, were accepted for the pilot training program in September, 1969. These men had an average of 2 years of experience in fire rescue work but no previous medical training beyond advanced first-aid. The pilot group received 180 h of classroom, laboratory and clinical instruction, followed by 6-9-month field service on a hospital-based vehicle (station wagon) accompanied by a cardiac care unit (CCU) nurse. Following implementation of state wide legislation [12] permitting Mobile Intensive Care Unit (MICU) paramedics to function without direct supervision, the subsequent 350 trainees received a training course consisting of over 400 h of classroom and laboratory instruction, direct clinical experience and field internship on a hospital-based training vehicle. The training period now lasts 5 months, 40 h!week. There are now two full-time training facilities operated by the Los Angeles County Paramedic Training Division with separate faculties at Harbor General Hospital and Los Angeles County-University of Southern California Medical Center, consisting of full-time nursing staffs supplemented by voluntary physician and
Downloaded by: University of Cambridge 131.111.164.128 - 1/31/2019 7:41:48 PM
Training Program
Mobile Emergency Care Units
11
technical staffs. The training encompasses scientific terminology, basic anatomy and physiology, over 50 h of cardiology, noncardiac emergencies including head trauma, fractures, burns and childbirth, and special techniques including cardiopulmonary resuscitation, venipuncture, intubation, intracardiac injections and inhalation therapy. The cardiac training consists of normal and abnormal physiology, myocardial infarction and its complications, cardiac pharmacology and a comprehensive arrhythmia course. The cost of training a county paramedic is $1,575, and the cost is borne by the county. Other fire departments requiring additional men to cover those in training expend approximately $ 6,000 in salaries for back-up personnel per man in training.
Legislation The Wedworth-Townsend Paramedic Act [12], drafted specifically to enable the MICU paramedics within the Los Angeles County to function without direct supervision, was signed into law in July, 1970. It was amended in June, 1971 (Assembly Bill 492), to encompass MICU paramedic programs throughout the state of California. Under the terms of the amended legislation, a certified MICU paramedic 2 may initiate cardiopulmonary resuscitation (CPR) and defibrillate a pulseless nonbreathing patient without professional supervision. Any therapy requiring parenteral (intramuscular, intravenous or intracardiac) medications requires authorization from a physician or certified MICU nurse 3 by radio or telephonic contact with a base station hospital. Six categories of drugs may be administered: antiarrhythmic, vagolytic, chronotropic, vasopressor, analgesic and alkalinizing agents, as well as intravenous glucose and electrolyte solutions. The physician and nurse are exempted from liability for civil damages resulting from instructions given 'in good faith', as are the paramedics under separate legislation [13].
Operation of MICU Teams
2 Certified by the appropriate county official, i.e. Director of Health Services, under provision of the Wedworth-Townsend Paramedic Act. 3 As for footnote 2.
Downloaded by: University of Cambridge 131.111.164.128 - 1/31/2019 7:41:48 PM
The initial 3 paramedic squads trained at Harbor General Hospital provided 3 model configurations which provided prototypes for the subsequent 46 squads trained in the next 4 years. Although each team received similar training, there were major differences in vehicles and modes of operation (table I). At the present time (January, 1974) 40~/o of the county has minimal paramedic coverage and approximately 550 additional paramedics will be needed for complete geographic coverage.
CRILEy!LEWIS/AILSHIE
12
Table I. Paramedic team configurations
MICUteam
Location
Vehicle
Comments
Station 59 LACo.FD
fire station on hospital grounds
originally a station wagon, later replaced by a high-top van (fig. 1)
hospital-based training unit; paramedics maintain close contact with physicians and nurses; paramedics work in CCU and emergency room between calls; requires private or contract ambulance for patient transport
Station 36 LA Co. FD, prototype for 22 other county rescue squads
fire station 1mifrom hospital
utility truck (fig. 2)
upgraded Fire Rescue Service, requiring no additional manpower or vehicles; unit responds to all emergency calls and fires; unit carries equipment for extrication of victims from vehicular accidents, burning buildings, cliff rescues, etc.; utilizes private or contract ambulance for patient transport
Station 53 LAFD, prototype for 4 other city rescue ambulances
fire station 10 mi from hospital
rescue ambulance (fig. 3)
upgraded Rescue Ambulance Service, requiring no additional manpower or vehicles; unit responds to all emergency calls; transports patient - not dependent on private ambulances
MICU = mobile intensive care unit; LA Co. FD = Los Angeles County Fire Department; CCU = coronary care unit.
Squad 59 is a Los Angeles County Rescue Unit operating from a small fire station on the Harbor General Hospital grounds, which originally utilized a station wagon and currently a high-top van, carrying battery-powered portable equipment and drugs. The 6 men work in 2-man shifts, 24 h on, 48 h off. They sleep and eat on the hospital grounds, and spend time between calls in the CCU and emergency room. These men wear white coats, are identified as 'MICU paramedics' with name-badges, and are permitted to participate in many clinical activities in the hospital. They are permitted to assist the CCU nurses, record electrocardiograms (ECG), initiate intravenous infusions, perform CPR and countershock therapy, and the like.
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Training Vehicle - Squad 59 (fig. 1)
Mobile Emergency Care Units
13
Fig. 1. Hospital-based training unit, located at Fire Station 59 on the Harbor General Hospital campus. This high-topped van functions as a training unit for paramedics completing the field portion of their 5-months training. They are supervised during this phase of their training by experienced paramedics. The portable cardiac resuscitative equipment is displayed in front of the open doors.
This unit is used as a trammg facility for paramedic trainees as well as experienced MICU paramedics for 'refresher' training. Squad 59 responds to all rescue calls received from the fire rescue dispatch operation, and the men can be reached by 'hot-line' telephones in the CCU and fire station, by hospital pages or via portable hand-carried radios. Their rescue response area consists of 59 mi 2 and overlaps the Squad 36 (see below). They may perform as a back-up unit for Squad 36.
Squad 36 is a Los Angeles County rescue unit based at a Carson fire station 1 mi from Harbor General Hospital and has a response area of 38 mi2 • The 6 men work in 2-man shifts, sleep and eat at the fire station, and wear fire department uniforms. They respond to all fires as rescue paramedics, as well as to all rescue calls relayed by the dispatch center. Their vehicle is a standard fire department utility truck, equipped with cliff rescue gear, extrication tools, etc., in addition to the portable MICU equipment. Neither Squad 59 nor Squad 36 transports patients to the hospital. A private or contract ambulance is called and, if indicated by the emergency or requested by the base-station physician, a paramedic with portable equipment accompanies the patient in the ambulance to the hospital.
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Fire Rescue Unit - Squad 36 (fig. 2)
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Fig. 2. a Utility truck of the type used by 23 fire rescue squads in the Los Angeles County Fire Departments. b The resuscitative equipment is stored inside a side panel on the truck.
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Fig. 3. Interior view of a Los Angeles City Rescue Ambulance which is typical of the 5 rescue ambulances maintained by the City Fire Department. The numbered items are: (1) bedboards for resuscitation; (2) battery-powered aspirator; (3) portable battery-powered electrocardiogram (ECG) oscilloscope; (4) portable battery-powered defibrillator; (5) portable transceiver for radio communications with base station; (6) cardiac drug box, and (7) first-aid equipment.
This unit is a Los Angeles City Fire Department unit located in the WilmingtonSan Pedro area, about 10 mi from Harbor General Hospital. It has a response area of 30 mi2 • The men wear fire department uniforms and they eat and sleep at the fire station. They respond to all emergency calls from the dispatcher and transport the patient to the hospital in their vehicle. Subsequent to 1972, the city fire department has employed civilian (nonfireman) paramedics.
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Rescue Ambulance 53 (fig. 3)
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CRILEY /LEWIS/AILSHIE
Table lIa. MICU portable equipment Approximate cost, $ 1. Electrocardiogram (ECO) oscilloscope, battery-powered 950.00 2. Portable transceiver with ECO amplifier and modulator 3,200.00 3. D.C. defibrillator. battery-powered 1,750.00 4. Inhalation equipment Ambulance bag Elder valve Oxygen Airways - oropharyngeal and esophageal 5. Aspirator, battery-powered 175.00 6. Drugs Vasoactive: norepinephrine, metaraminol, epinephrine, isosorbide dinitrate, glyceryl trinitrate, isoproterenol Chronotropic: isoproterenol Vagolytic agents: atropine Antiarrhythmic: lidocaine Intravenous solutions: 5 % dextrose, normal saline, Ringer's lactate, dextran Analgesics: morphine, pentazocine (Talwin®) Antidotes: 50 % glucose, nalline Electrolyte concentrates: calcium chloride, sodium bicarbonate Miscellaneous: forosemide, benedryl, syrup of ipecac Sedatives, anticonvulsants: phenobarbital, diazepam (Valium®) 7. Miscellaneous Stethoscope Sphygmomanometer Splints - vacuum type Obstetrical equipment
Table lIb. Base-station (hospital) equipment Approximate cost, $ 2,300.00 4,000.00
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1. Base-station transceiver with duplexer and antenna 2. Base station console Cassette tape-recorder Strip chart recorder Demodulator Oscilloscope
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Fig. 4. Base station console at Harbor General Hospital consisting of transceiver, ECG demodulator, ECG oscilloscope, strip chart recorder and cassette tape-recorder for recording voice and ECG transmission. A coronary care unit (CCU) intern and certified mobile intensive care unit (MICU) nurse are communicating with the MICU, and a permanent record is made of each call by use of recorded data on the cassette tape.
Emergency Equipment All paramedic fire rescue squads and rescue ambulances carry essentially identical portable equipment (table II, fig. 1-3) costing approximately $ 6,000, consisting of cardiac and non-cardiac instrumentation and medications. This equipment can be hand-carried into the home, factory or scene of an accident. A major advance in airway maintenance has resulted from the use of the Gordon-Don Michael esophageal airway [14], an inexpensive device which can be inserted in less than 30 sec after brief training.
For these 3 prototype units and three subsequent units the base station at Harbor General Hospital in Torrance, California, is a 700-bed teaching hospital which functions as the southern campus of the University of California, Los Angeles (UCLA), Medical School. The CCU was chosen as the operational base because of
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the immediate 24-hour availability of a physician and certified MICU nurse. The emergency room is consulted or alerted by telephone by the CCU staff in the event of burns, trauma or other emergencies requiring additional expertise. 18 subsequent base-station hospitals have entered paramedic-supervisory operation, the majority being private, non university affiliated community hospitals without house staff coverage. Some of these community hospitals utilize the emergency room rather than the CCU as a base-station facility, and must rely on the MICU nurses for the majority of the radio-telemetric supervision of the paramedic teams. The base-station console (table II, fig.4) consists of a transceiver, ECG demodulator oscilloscope, strip chart recorder and cassette tape-recorder. A back-up 'hotline' telephone system may be used for voice or ECG transmission in case of technical difficulties with radio (a rare occurrence). Each incoming call from a paramedic team
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Fig. 5. Resuscitation of patient (C. D., aged 62 years; 6.3. 1971) with ventricular fibrillation (VF) due to acute myocardial infarction. VF (top panel) was present when MICU arrived. Defibrillation resulted in complete heart block (second panel) which spontaneously converted to normal sinus rhythm.
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is received by an intern or resident physician and recorded on cassette tape for later review by a staff physician. The ECG is received as a frequency-modulated (FM) tone signal which is recorded on cassette tape and can be displayed on the oscilloscope and recorded on the strip chart recorder. The cassette tape can be replayed to review both the voice and electrocardiographic data at any future time. Only on rare occasions is the telemetered ECG not of diagnostic quality for the interpretation of arrhythmias. A common problem is distortion of the ST segment, caused by lowfrequency filtering.
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Fig. 6. Resuscitation of patient (M. T., aged 16 years; 16.4. 1971) with VF secondary to aspiration. VF was present when MICU arrived (top panel). Following defibrillation, complete heart block occurred with ventricular asystole (second panel); idioventricular rhythm then developed with multiple premature ventricular contractions (PVC) (third and fourth panels). Ventricular flutter ensued (fifth panel) and was not responsive to D.C. countershock, but was converted to a supraventricular tachycardia following lidocaine administration. At this time, a blood pressure of 180/ 40 mm Hg was obtained. CPR = cardiopulmonary resuscitation.
CRILEyjLEWIS!AILSHIE
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Typical Operation A patient in distress may dial the fire rescue or rescue ambulance dispatch number directly, state the nature of the complaint and give his name, age and address. As the dispatcher does not attempt to categorize or screen calls, delays in dispatching paramedics to the scene are kept to a minimum. The average response time from the paramedics' receipt of the call from the dispatcher to arrival at the scene is 5.6 min. Upon arrival at the scene, the paramedics briefly question and examine the patient and institute any necessary emergency resuscitative procedures. Electrocardiographic leads (self-adhering chest electrodes) are placed on the patient if indicated, and contact is made by radio with the physician in the CCU. The physician directs the course of treatment, such as starting intravenous infusion, drugs or possibly countershock. As noted above, the paramedic may employ CPR and countershock before contacting the physician in dealing with pulseless, nonbreathing patients (fig. 5, 6). If transportation to the hospital is required, a private (contract) ambulance is dispatched to the scene (if not there already), and that ambulance is upgraded to a MICU by the addition of one or more paramedics and their specialized portable equipment. Before transport, every attempt is made to stabilize the condition of the patient by institution of an adequate airway, countershock therapy, the administration of antiarrhythmic drugs and sodium bicarbonate and the institution of antihypotensive medications as indicated. When stabilization has been reached (or reasonable attempts to bring it about have failed) the patient is transported to the hospital. Rapid transport with red light and siren (Code 3) is avoided when the patient has stable vital signs. If the patient has a cardiac problem, he is taken directly from the ambulance to the CCU, accompanied by the paramedics and their portable equipment. During transport, constant contact with the base-station physician is maintained. Most patients are transported to Harbor General Hospital, but they may request to be taken to a private hospital, in which case the base-station physician calls the hospital to inform the physician or nurse on duty in the emergency room. If possible, the patient's private physician is contacted also. In cases of obvious cardiac distress (i.e., suspected myocardial infarction, significant arrhythmias, hypotension, etc.) a direct admission to the CCU in the outside hospital is arranged. No additional charge (above that of the private ambulance fees) is rendered the patient by the Los Angeles County Fire Rescue Paramedic Service.
The rapidly expanding program now comprises 49 MICU paramedic units serving 19 base-station hospitals, and covers approximately 40010 of Los Angeles County and its incorporated cities with advanced rescue capabilities. As of December, 1973, 50,909 rescue calls were made, of which 9,310 (18.2010) had primary or significant cardiac problems. The
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Results
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cost of implementing this enhanced rescue service, including training costs, portable MICU equipment (not including expendable supplies) and basestation equipment has been slightly over $1,000,000 - or approximately $0.36 per citizen covered by paramedic service - or $19 per rescue call. This latter figure will decrease as the number of calls increases, since many of the MICU paramedic squads have less than 6 months of service. Detailed statistics on the nature of cardiac problems encountered by all of the paramedic units are not available, but the following data represent statistics derived from the paramedic rescue squads serving the base-station at Harbor General Hospital.
Resuscitation from Ventricular Fibrillation In 3 ~ years, 246 patients with ventricular fibrillation were encountered in the field, and 70 (280/0) could be restored to a supraventricular rhythm at the time of transport to the hospital. 20 of these patients (8 % of those in ventricular fibrillation) survived to leave the hospital. A detailed analysis was made of the first 12 long-term survivors [15] which occurred in the first 30 months of paramedic operation at Harbor General Hospital. During that time 4,749 patients were treated by the paramedics, and a significant cardiac problem (cardiac arrest, myocardial infarction, congestive failure, angina, arrhythmia, etc.) was encountered in 902 patients (190/0). Ventricular fibrillation outside the hospital was documented in 137 (fig. 7), or 150/0, of the patients with significant cardiac problems. In 44 (32 Ofo) of the patients with ventricular fibrillation, field resuscitation was successful in restoring a supraventricular rhythm which was maintained up to the time of arrival at the hospital. Of the 44 successful resuscitations 32 died in the hospital: 15 in the first hour, 10 within 72 h and the remainder in the first 7 days of hospitalization. 12, or 8.80/0, of the patients with ventricular fibrillation survived to leave the hospital. Their subsequent courses are displayed graphically in figure 8.
The prehospital incidence of ventricular arrhythmias other than ventricular fibrillation among cardiac patients has been 32 % premature
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Fig. 8. Symptomatic classification (according to New York Heart Association [NYHA]) in 10 patients with coronary heart disease before resuscitation from ventricular fibrillation (VF), and following release from the hospital.
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Mobile Emergency Care Units
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ventricular contractions and 12010 ventricular tachycardia. These arrhythmias were treated by intravenous lidocaine and countershock, if indicated; no deaths occurred during the paramedic run in these patients.
Myocardial Infarction Major complications encountered in patients with myocardial infarction entering the CCU via the MICU consisted of: major arrhythmias, 30010; cardiogenic shock, 90/0; pulmonary edema, 26010; death, 11010. There was no significant difference in incidence of these complications in MICU patients as compared to patients with myocardial infarction admitted to the CCU via the usual channels. It was anticipated that MICU patients would actually have higher morbidity and mortality, since they had called for emergency aid rather than entering the hospital by conventional means. When the total duration of symptoms prior to admission to the CCU was less than 2 h, 53 010 had no complications, and this percentage fell to 37 0/0 (p 0.001) if CCU arrival was delayed from 2 to 12 h.
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