Virtual Museum EMS History

Planning and Developing a Prehospital Mobile
Intensive Care System in an Urban Setting

EMIL F. PASCARELLI, MD, AND IRWIN B. KATZ, MPH

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Abstract: A suggested model for the development of an urban based prehospital emergency care system is described. Factors considered in the planning and development include: 1) demand for services, projected and actual; 2) analysis of costs; 3) design and maintenance of the delivery system; and 4) establishment of the evaluation mechanisms. Over one year's experience and 1,144 mobile intensive care unit (MICU) calls in a densely populated urban setting with over 500,000 persons are reported. During the peak 8-hour period, predetermined dispatch categories were employed to activate one MICU operating in conjunction with three conventional ambulances. This partial conversion imparted MICU capability to the entire system at an 11 per cent increase in the ambulance budget. MICU calls averaged 4.5 per 8-hour peak shift and took 45 minutes each. (Am. J. Public Health 68:389-393, 1978)

Introduction

    The introduction of the concept of prehospital emergency care, utilizing trained first responders, paraprofessionals, professionals, and ambulances with biotelemetric capability has extended sophisticated emergency care services beyond the physical confines of the hospital. Various systems are already in operation throughout the world'-⁶ The purpose of this article is to suggest a model for the design of an urban prehospital care delivery system taking into account the costs involved, the approach to establishing and maintaining new programs, and the question of the general distribution of resources in terms of the medical commons.⁷

Method and Program Development

    In 1973, Beekman Downtown Hospital (BDH) in New York City adopted a plan to reorganize its prehospital emergency services. At that time, New York City's emergency medical system (EMS) provided basic life support response to medical emergencies utilizing a central dispatching system activated by dialing 911 on the telephone. The system was part of the city's Health and Hospital Corporation which controlled the dispatching of ambulances in 15 municipal hospitals and 22 private voluntary hospitals with which it contracted. Beekman Downtown Hospital was in the latter category.

    In July 1974, the city's first advanced life support program using paramedics was established in a Bronx municipal hospital on a trial basis. Beekman Downtown Hospital's program was the first in the City to be established by a voluntary hospital. Support was obtained through funding from private sources. The primary challenge was to integrate an advanced life support system into a previously established basic life support system. BDH, with 306 beds, a teaching program, a model emergency facility, and coronary and surgical intensive care units was able to provide the elements for establishing a continuum, linking prehospital and hospital care. Beekman Downtown Hospital has a long standing commitment to the delivery of emergency care8 linked to the necessity of serving a community of 575,000 working and residential persons in 3.2 square miles of Lower Manhattan. Because about half-a-million of these persons are workers who enter and leave the area daily, Beekman Hospital experiences  its peak emergency services demand during the period between 8 AM and 4 PM on weekdays.

    Analysis of data for 1974 revealed a total of 34,987 emergency department visits, of which 8,654 persons (25 per cent) arrived by ambulance. Approximately 50 per cent of these ambulance calls were made on weekdays between 8 AM and 4 PM reflecting the large proportion of working commuters. The average length of time of a conventional ambulance run from dispatch to return to hospital was 19.5 minutes. A profile of ambulance calls was obtained using the existing New York City EMS Priority I dispatch categories as the basis for analysis. Priority I classification was the most critical group of calls triaged by New York City's central dispatching unit and included the categories of cardiac, unconscious, difficulty breathing, serious trauma, person in distress, possible DOA, and "miscellaneous." The preponderance of calls relayed to BDH in the Priority I category occurred during the weekday daytime hours (3.6 calls per weekday during the hours of 8 AM to 4 PM) with a high frequency of cardiac-related incidents. Though fewer in number, the calls in the serious trauma and other non-cardiac related categories suggested a need for a broad mobile intensive care unit potential. As noted, in 1974, the average conventional ambulance call took approximately 20 minutes to complete. Deployment of the MICU rendering definitive care was expected to double the time from dispatch to return of the vehicle and was, therefore, estimated at 40 minutes. With an anticipated work load of 3.6 calls per day taking at least 40 minutes each, actual MICU working time in the field would consume 2.4 hours per 8-hour period. Priority I call response capability could be provided by one MICU unit at these levels of demand.

    Anticipated services included a high percentage of cardiac calls requiring the potential for performing effective cardiopulmonary resuscitation (CPR), carrying several pieces of equipment, drugs, intravenous solutions, communication gear, and stretchers. Experience with existing programs indicated that a minimum of two emergency medical technicians, trained and certified at a level of EMT-P were required to perform these duties.

    In 1974, the New York City EMS system had predominantly basic life support capabilities. This meant that Beekman's single advanced life support ambulance had to operate within the framework of a basic life support system, and offered the opportunity to conceptualize and test a "tandem system" in which the MICU responded selectively to Priority I calls along with a conventional ambulance. In this case, one of four conventional ambulances was replaced by a MICU. This approach was felt to offer the advantage of flexibility by permitting further triage at the scene to determine if the MICU was actually needed. Moreover, it could impart the MICU's capabilities to the entire system of the hospital's three remaining conventional ambulances.

    The next factor to be considered was the cost of the system. Anticipated costs were separated into three categories: capital expenditures; salaries of personnel; and expendable supplies, equipment and maintenance. The MICU program did not include the salaries of an ambulance driver, physician director, or ancillary support services since these were already in existence in the hospital.*
An evaluation system which would generate a broad data base was developed and considered a vital aspect of the program. Future plans for easy conversion to a computerized system were made and were recognized as an important goal. This included the establishment of separate medical records, a patient tracking system, and medical audit. * The cost of the paramedics' salary in our case was partly offset by that of the replaced EMT-I who was no longer part of the MICU system. Data were also generated to assist in the evaluation of productivity and costs.

Results

    A system like the one described was initiated in October 1975. During its first year of operation, the total number of ambulance calls made was 9,673. Of these, 5,008 calls (52 per cent) were made during the hours of 8 AM and 4 PM when the back-up MICU was available. During this time, in 1,144 instances (22.8 per cent), response was made by the MICU and a conventional ambulance in tandem responding to New York City's EMS designated Priority I calls. The average number of MICU calls was 4.5 per day versus the anticipated figure of 3.6. ^{(Table 1)}

    The average call took 45 minutes versus a projected 40 minutes. This resulted in actual time in the field averaging 3.3 hours daily as compared to an anticipated 2.4 hours. Additional time was spent by paramedics in areas not initially considered, including follow-up care in the emergency department and critical care units. Time was also spent replenishing drugs and supplies, maintaining the vehicle in a state of readiness, reviewing and critiquing calls, maintaining skills, and teaching, as well as keeping patients' records and statistics. These figures suggest that for every hour spent by the paramedic in the field, an additional hour is required for maintenance, review, evaluation, patient follow- up and other functions. They underscore the professional responsibilities of the paramedic. If increased demands for field time by paramedics were made, some of the in-hospital tasks might be performed by other paraprofessionals such as the EMT-1.

    Establishing a separate MICU patient chart and integrating this information into the Hospital's overall medical records system enabled us to conduct a rough evaluation of the program. Prior to case research being conducted, "definitive care" was explicitly defined as: "Care rendered in which advanced life support skills were employed on the scene. These skills include such procedures as defibrillation, delivering medication, drawing blood, starting an intravenous line, performing etidotracheal intubation, drawing arterial blood gases, and inserting a nasogastric tube."

    A review of cases was made to determine whether or not "definitive care" was rendered by the paramedic team. No attempt was made to evaluate these data in terms of quality or outcome. More rigorous medical care audit studies, employing statistical techniques to evaluate quality of care as well as reliability, are currently being conducted and will be the subject of future communications. The frequency of cases where "definitive care" was rendered by the paramedic team, within each EMS dispatch category, is displayed in Figure 1. Overall, "definitive care" was delivered in 46 per cent of the 1,144 MICU calls. Conversely, in 54 per cent of all calls, no definitive care was delivered and it was documented that the MICU returned to the hospital or was reassigned to another call from the scene. Calls received by the hospital under the category "possible DOA" were confirmed as accurate on the scene in a high percentage of cases (83 per cent), thereby making it the most reliable dispatch category, although not requiring definitive prehospital care.

    The tandem use of ambulances also provided the benefit of bringing additional manpower to the scene when complex resuscitative measures, crowd control, specialized transportation, or other tasks related to delivering prehospital care in an urban setting needed to be performed. This backup function was utilized in 36 per cent of all calls. An analysis of costs was also undertaken and is summarized in Table 2. The estimated cost of providing conventional ambulance service for the peak hours of 8 AM to 4 PM was $1 15,000. The additional personnel expense to provide MICU coverage during these hours was projected at $28,200 per year. The major addition in cost involved the salaries of the trained paramedics minus the salary cost of one EMT-1.
There was no increase in driver cost, since the fourth driver was assigned to the MICU. Because of the type of care rendered by the MICU staff, the cost of drugs and other supplies was about seven times greater, amounting to $6,000. Part of this sum was merely the allocation of already existing emergency department expenses to the prehospital area. The ambulance and related communications equipment, including the hospital base station, cost approximately $60,000. For comparison purposes, these capital expenditures, although delineated in Table 2, are not included in the cost comparisons which follow. For reimbursement, depreciation is allocated on a departmental basis on other hospital cost reports. Providing MICU coverage for the peak 8 AM to 4 PM period, using a total of four ambulances including one MICU, increased costs by 25 per cent over the original program. If this is taken as a percentage of the entire cost of the ambulance department, it becomes an 11 per cent increase.
If expressed in terms of the Lower Manhattan population served by the system, the annual cost of adding MICU coverage from 8 AM to 4 PM is approximately 4.9 cents per person.

Discussion

    Our experience with the selective tandem deployment of the MICU has pointed the way to the development of a hospital-based prehospital emergency response system geared to provide comprehensive services, while keeping expenditures to a minimum. Variations on this principle can adapt to a variety of situations, including a congested urban environment where further research is warranted. It is important that dispatch of MICUs be based on predetermined categories of priority in order to maximize their effectiveness. With an initial investment in a trained paramedic team and an adequately equipped ambulance with a telemetry medical command system, prehospital mobile intensive care can be made available for an existing conventional ambulance service using the principle of tandem operation even though the area's system is providing predominantly basic life support.To provide this enhanced capability, operating expense for a five-day, eight-hour shift in our experience represented a 25 per cent increase over the cost for operating that shift. Extension of this service to other hours of the day requires an investment in personnel but not necessarily in equipment. Extending this service beyond the period of the highest frequency of Priority I calls may increase the number of hours the service is available to the community, while reducing the cost effectiveness of the system. Such priorities must be weighed when designing individual systems.

    The greater the number of conventional ambulances that the MICU can cover, up to a critical point, the more the operating expenses can be spread over a greater area of the community. This would lower the per capita cost of providing this service and strengthen the possibility that in an urban setting it might not be necessary for a total conversion to an advanced life support system.

    The system proposed in this article recognizes that there are moral obligations to provide certain expensive but potential life-saving services to as many members of the community as possible.9 Even though the MICU system is desirable, it is not always possible to obtain and support. Instead, every effort should be made to strategically place a limited number of these units where demand is greatest. If cost benefits are taken into account and resources more effectively distributed, a greater number of persons will be able to share in the services offered.⁷

    This study raises other questions which need further investigation and evaluation. These include assessment of the effects of prehospital emergency care in long-term survival, ¹⁰ as well as evaluation of preventive intervention, such as the use of antiarrhythmia agents for incipient cardiac arrythmias." The basic question of the impact of the MICU on a community for given disease categories in terms of their effects on morbidity and mortality has yet to be extensively investigated.'2 In other categories, such as serious trauma and respiratory distress, such evaluation is more difficult.

    The data presented also refer to the productivity of various EMS dispatch categories in New York City based upon on-site evaluation. These data can be used to further maximize the effectiveness of a system where limited resources must be made available to a large service area.¹³ Other devices, such as the training of lay citizens in CPR, may further increase the efficiency of the prehospital care service.^{10 14} hospital-based prehospital emergency response system geared to provide comprehensive services, while keeping expenditures to a minimum. Variations on this principle can adapt to a variety of situations, including a congested urban environment where further research is warranted.

    It is important that dispatch of MICUs be based on predetermined categories of priority in order to maximize their effectiveness. With an initial investment in a trained paramedic team and an adequately equipped ambulance with a telemetry medical command system, prehospital mobile intensive care can be made available for an existing conventional ambulance service using the principle of tandem operation even though the area's system is providing predominantly basic life support.

 To provide this enhanced capability, operating expense for a five-day, eight-hour shift in our experience represented a 25 per cent increase over the cost for operating that shift. Extension of this service to other hours of the day requires an investment in personnel but not necessarily in equipment. Extending this service beyond the period of the highest frequency of Priority I calls may increase the number of hours the service is available to the community, while reducing the cost effectiveness of the system. Such priorities must be weighed when designing individual systems.

REFERENCES

1. Pantridge, J. F., Geddes, J. S. A mobile intensive care unit in the management of myocardial infarction. Lancet 2:271, 1967.
2. Pantridge, J. F., Adgey, A. A. J. Pre-hospital coronary care: the mobile coronary care unit. Am. J. Cardiol 24:666-673, 1969.
3. Grace, W. J. The mobile coronary care unit and the intermediate coronary care unit in the total systems approach to coronary care. Chest 58:363-368, 1970.
4. Rosati, M. D., Granatelli, A., Lustig, G. J., et al. Community hospital mobile coronary care unit. N.Y. State J. Med. 70:2462- 2465, 1970.
5. Luger, G. W., Kalsters, W. Preliminary experience with a mobile coronary care unit (cardulance). Folia Med. Neerl. 14:187- 195, 1971.
6. Chamberlain, D. A., White, N. M., Binning, R., et al. Mobile coronary care provided by ambulance personnel. Br. Heart J. 35:550, 1973.
7. Hiatt, H. H. Protecting the medical commons: Who is responsible?
N. Eng. J. Med. 293:235-241, 1975.
8. Kennedy, R. H. Transportation of the injured with particular reference to fractures of the extremeties. Bull. Am. Coll. Surg. XVII: 2, 21-30, 1933.
9. Noble, B. K. Toward a system of emergency medical care. N. Eng. Med. 294:609-611, 1976. 392 AJPH April 1978, Vol. 68, No. 4
10. Cobb, L. A., Baum, R. S., Alvarez, H., et al. Resuscitation from out-of-hospital ventricular fibrillation: 4 years follow-up. Circulation 52:6 Suppl. III. 223-228, 1975.
11. Rapaport, E. Pre-hospital ventricular defibrillation. Editorial. N. Eng. J. Med. 291:358-359, 1974.
12. Sherman, M. A. An evaluation of the effectiveness of mobile intensive care units in reducing deaths due to myocardial infarction. Unpublished PhD dissertation, Northwestern University, 1977.
13. New York Times: New York City plans to overhaul outmoded system of ambulances. Article by Jane E. Brody and Ronald Sullivan, May 30, 1977.
14. New York Daily News: Citizens CPR course. Brenda Woods, June 28th, 1977.

Address reprint requests to Irwin B. Katz, MPH, Assistant Administrator, Beekman Downtown Hospital, 170 William Street, New York, NY 10038. Dr. Pascarelli is Chief of Ambulatory Care at the hospital. This paper, submitted to thp Journal June 6, 1977, was revised and accepted for publication September 6, 1977.

 EDITORS NOTE- Several tables were not reproduced on this page. To view them, download the original  article:  Planning and Developing a Prehospital Mobile Intensive Care System in an Urban Setting

Keywords: NYC EMS, New York City, Beekman Downtown Hospital, MICU, Paramedic

Last Revision Date: 12/5/11 - 11:56 PM