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• In the 12 years from 1984 to 1995, Adelaide-based mobile intensive care teams transported 4443 critically ill patients from rural areas in South Australia and adjacent States to tertiary-level hospitals in Adelaide.
  
• The SA Ambulance Service undertook communications, support staffing and deployment of transport.
  
• Average radial distances in 819 road missions were 71 km, in 808 helicopter missions 122 km, and in 2777 fixed-wing aircraft missions 398 km.
  
• The largest groups of patients were neonates (23%) and those with trauma (25%).
  
• Rural hospitals made 96% of the requests for intensive care transport; 4% came from ambulance or other emergency service crews at accident locations.
  
• Emergency surgical or operative obstetrical procedures were performed on 2.7% of patients before transport.
  
• One hundred and thirteen patients (2.5%) died during resuscitation or transport, with one death deemed to be preventable.

This system was first reported in the Journal in 1977.¹ This article describes the function and outcomes of the mobile intensive care service from 1984 to 1995.

Rural hospitals were connected to intensive care units at the tertiary centres by dedicated telephone lines so that rural medical officers could obtain emergency advice, contact other specialists and arrange transfer of patients. Mobile teams consisted of a consultant or senior trainee in intensive care, anaesthesia or emergency medicine and a critical care nurse, commonly assisted by a paramedic or Royal Flying Doctor Service (RFDS) nurse. Other specialists (eg, surgeon, obstetrician) travelled as required.

The SA Ambulance Service Communications Centre co-ordinated transport and provided supporting staff. Very high frequency radio and mobile phones linked road ambulances, aircraft, tertiary centres and rural hospitals.

A twin-engine, pressurised Super KingAir B200C fixed-wing aircraft of the RFDS, carrying a pilot and up to five cabin crew, two stretchers and a stretcher-loading device,² was used for most long-distance transfers. Recently, Pilatus PC XII aircraft of similar performance have been used. The helicopter used was a twin-engine Bell 412 helicopter of the State Government Insurance Commission-State Rescue Helicopter Service, with 2-4-stretcher capability, pilot, crewperson and up to three medical crew as needed.

The Department of Human Services, Royal Flying Doctor Service (Central Section) Medical Review Committee and the SGIC-State Rescue Helicopter Committee audited the operations of the mobile intensive care service.

At times, the service was extended to remote areas in other States. Box 1 shows the range of operations.

One hundred and thirteen patients died (2.5%) during resuscitation or in transit. One preventable death resulted from an endotracheal tube displacement in transit, which was managed unsuccessfully by emergency tracheostomy at a nearby hospital.

Box 3 lists the procedures performed to stabilise patients before transport. A third of patients required endotracheal intubation. Major biochemical disturbances commonly involved potassium or glucose levels. Hypothermia and hyperthermia were corrected to the degree possible.

Box 4 lists emergency surgical and obstetrical procedures undertaken before transporting patients.

Effective care for critically ill rural patients requires an integrated hierarchy of rural and city hospitals, ambulance services, the RFDS and mobile intensive care. Larger rural hospitals have specialist surgical and anaesthetic services, but may lack tertiary centre services such as neurosurgery, burns, spinal injuries, specialised organ imaging, extensive transfusion facilities and major (level III) intensive care.^4,5

Because of the large distances involved, staff at tertiary intensive care units encouraged rural medical officers to start a dialogue early with the retrieval service whenever a patient might require retrieval. Intensive care units provided necessary advice while the team was in transit.

After stabilising the patient, treatment in transit was commonly restricted to adjustment of sedation, infusion rates and ventilator settings. The transfer of patients immediately after emergency surgery or obstetric procedures was uneventful.

Obstetric conditions requiring transfer included eclampsia and major blood loss. The number of obstetric patients declined from 1984 to 1995 as improved antenatal care identified at-risk pregnancies, with elective movement of mothers to a major centre.

A surgeon did not usually accompany the mobile intensive care team, largely because the surgical facilities in small rural hospitals were limited.

There were 30 patients with suspected extradural haematoma, for whom a local medical officer commenced burr holes, directed by telephone, pending arrival of the team (accompanied by a neurosurgeon in 16 cases) to complete the procedure and retrieve the patient. Data suggest that such emergency drainage of an extradural haemorrhage is a valid procedure if the patient is more than two hours from a trauma centre.⁶

Ambulance crews at rural accident sites with multiple victims or patients deteriorating during prolonged entrapment were encouraged to request support when needed from local medical officers and/or retrieval teams. While primary (site) retrieval was requested in 149 instances (13% of trauma cases), distance commonly decreed that teams would attend after patients had been transferred to the local hospital. This contrasts with some overseas services that perform mainly primary retrieval missions by helicopter over shorter distances.^7-9

Paramedic services provide a high level of care, but retrieval teams have a different role, with a wider therapeutic armamentarium and the ability to undertake major procedures in rural hospitals. Advanced trainees or consultants in intensive care, anaesthesia or emergency medicine, and their nurse counterparts, provide requisite clinical experience and procedural skills. To be effective, they must also be able to work in unfamiliar hospitals, in vehicles and other restricted sites, and they must have insight into the problems of rural doctors and nurses and the concerns of patients and relatives.

Fixed-wing aircraft and helicopter services are complementary. Fixed-wing aircraft mobilisation from Adelaide took 45-60 minutes, commonly for distances beyond 200 km. Executive or passenger jet aircraft complete extended trips (eg, Darwin, 2600 km) in half the time of turboprop aircraft. RAAF services assisted in five early cases. Pressurised aircraft were introduced in 1988, enabling smooth, rapid flight above adverse weather and allowing sea-level cabin pressure (eg, in decompression sickness).

The helicopter's rapid mobilisation, ability to land close to an incident, and reduced need of supportive road transport offsets slower airspeed. Helicopter transit times, commonly 50 minutes shorter than road transport, were improved by helipads at tertiary centres. Sports fields, lit at night, proved acceptable helipads in country areas. While road transport was used for shorter trips or if aircraft were unavailable, road transfer by local medical officers or ambulance staff (often with inadequate supportive resources) was commonly less satisfactory than if local staff continued resuscitation in the hospital pending arrival of a team.

Safe transport requires compact ventilators, infusion pumps and monitors with modest consumption of medical gases and battery power. Monitoring by the mobile teams included electrocardiography, pulse oximetry, core temperature, end-tidal carbon dioxide and (for neonates) transcutaneous measurement of respiratory gases. Intravascular blood pressure and central venous pressure measurements were especially useful, as pulse oximetry and non-invasive blood pressure measurements have limited reliability in hypothermia, shock^10,11 and during transport.

Neonatal transport incubators weigh about 100 kg, requiring a stretcher base, ventilator, monitors and heating for all phases of transport,¹² as combating hypothermia remains the most necessary component.

Early transfer of the critically ill has been associated with improved survival.¹³ Results of care in larger tertiary units are often better than in smaller, local hospitals, especially for severe trauma,¹⁴ neonatal¹⁵ and paediatric intensive care.¹⁶

See Box 5 for some case histories.

1. Gilligan JE, McCleave DJ, Nicholson B, et al. Retrieval of the critically ill in South Australia: a coordinated approach. Med J Aust 1977; 2: 849-855.
2. Gilligan JE, Goon P, Maughan G, et al. An airborne intensive care facility (fixed wing). Anaesth Intens Care 1996; 24: 245-253.
3. Runcie C. Principles of safe transport. Chapter 3. In: Morton NS, Pollack MM, Wallace P, editors. Stabilisation and transport of the critically ill. New York, London, Melbourne: Churchill Livingstone: 1997.
4. Faculty of Intensive Care. Australian and New Zealand College of Anaesthetists. Minimum standards for intensive care units (IC-1, 1994). Melbourne: ANZCA, 1994.
5. Report of the AHMAC (Australian Health Ministers Advisory Council) Aeromedical Services Working Party. Canberra: Commonwealth Department of Health, Housing, Local Government and Community Services, 1993: 47.
6. Simpson DA, Heyworth JS, McLean AJ, et al. Extradural haemorrhage: strategies for management in remote places. Injury 1988; 19: 307-312.
7. Grabosch A. Ten years experience in helicopter rescue in West Germany. Proceedings of the First International Assembly on Emergency Services. Washington DC: US Department of Transportation, 1982: 222-228.
8. Poisot D. Presentation du SAMU 33. SAMU 33 1994. Paris: Societé Assistance Medicale d'Urgence, 1994: 5-13.
9. Morley AP. Prehospital monitoring of trauma patients: experience of a helicopter emergency service. Br J Anaesth 1996; 76: 726-730.
10. Clayton DG, Webb RK, Ralston AC, et al. A comparison of 20 pulse oximeters under conditions of poor perfusion. Anaesthesia 1991; 46: 3-10.
11. Rutten AJ, Ilsley AH, Skowronski GA, Runciman WB. A comparative study of the measurement of mean arterial blood pressure using automatic oscillometers, arterial cannulation and auscultation. Anaesth Intens Care 1986; 14: 58-65.
12. Duncan AW. The critically ill child. Chapter 101. In: Oh T, editor. Intensive care manual. 4th ed. London: Butterworth-Heinemann, 1997.
13. Purdie JA, Ridley SA, Wallace PG. Effective use of regional intensive therapy units. BMJ 1990; 300: 79-81.
14. West JG, Cales RH, Gazzaniga AB. Impact of regionalisation: the Orange County experience. Arch Surg 1983; 118: 740-744.
15. Harris BA Jr, Wirtschafter DD, Huddleston JF, Perlis HW. In utero versus neonatal transportation of high risk perinates. A comparison. Obstet Gynecol 1981; 57: 496-499.
16. Pollack MM, Alexander SR, Clarke N, et al. Improved outcomes from tertiary center pediatric intensive care: a statewide comparison of tertiary and non-tertiary care facilities. Crit Care Med 1991; 19: 150-159.
17. Girotti MJ, Pagliarello G, Todd TR, et al. Physician-accompanied transport of surgical intensive care patients. Can J Anaesth 1988; 35: 303-308.

Department of Human Services, Adelaide, SA.
Michael T Jelly, FRACMA, Chief Medical Officer.

Women's and Children's Hospital, Adelaide, SA.
David G Morris, FRANZCOG, Head of Obstetrics, Department of Perinatal Medicine;
Ross R Haslam, FRACP, Head of Neonatal Medicine, Department of Perinatal Medicine;
Neil T Matthews, FFICANZCA, FANZCA, Medical Unit Head, Paediatric Intensive Care.

Flinders Medical Centre, Adelaide, SA.
Evan R Everest, FRACP, Director, Trauma Services and Specialist, Intensive Care;
Robert L Bryce, MSc, PhD, FRANZCOG, Director of Obstetrics, Department of Obstetrics and Gynaecology;
Peter B Marshall, FRACP, Director, Neonatal Medicine.

The Queen Elizabeth Hospital, Adelaide, SA.
Ron A Peisach, FFICANZCA, Director, Intensive Care Unit.

Reprints: Dr J E Gilligan, Intensive Care Unit, Royal Adelaide Hospital, Adelaide, SA 5000.
jgilligaATmedicine.adelaide.edu.au

©MJA 1999
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