Definition

1. Process of transferring critically ill patients using a team which travels to the patient location from a central location or the destination hospital. The principles of medical retrieval are to:
   1. Supply a level of medical expertise akin to that of the destination hospital.
   2. Assess the clinical problem in the place of referral.
   3. Stabilise the patient’s condition prior to transportation.
   4. Transport the patient with physiological support & appropriate monitoring.
   5. Deal with foreseeable en route deteriorations as the working environment allows.
   6. Monitor and review the quality of the retrieval process.

General considerations

Select patient

1. No abs CI to air medical transfer as long as appropriate precautions taken.
2. Benefit of transport must outweigh increased risks of transport.
3. Must require care available at destination not available at source facility.
4. Necessary care must be able to be provided during transport.

Relative CI to air retrieval:

1. Bronchopleural fistula
2. Bowel surgery<10d
3. Active GI bleeding
4. Vascular anastomosis<14d

Select mode of transportation

1. Road vehicle
   1. Standard ambulance
   2. High level care ambulance (Paramedic staff) ± Nursing/medical staff
   3. Specialist retrieval team + vehicle
2. Air medical
   1. Helicopter
      1. Indications for 1º helicopter retrieval: trauma score<12, GCS<10, BPsys<90mmHg, 10>RR>35, 60>HR>120, AVPU below V.
      2. Halves road transit time for distances 50-200km.
      3. Good for poorly accessible areas – mountainous/over large water expanses
      4. Faster mobilisation than fixed-wing
      5. Needs smaller landing area & can land closer to or at hospitals
      6. Cabin cons: noise level/communication, size limitation, cramped, temperature control, vibration, unpressurized
      7. Safety: approach wrt rotors.
   2. Fixed-wing
      1. Distances >200km or road transport times >3h
      2. Unpressurised if <900km light aircraft at alt to 3000m
      3. Pressurised (usually to 2000m) if >900km turboprop/jet at alt to 8000m+
      4. Pros compared to helicopter: faster airspeed, more cabin space, less noise/vibration, better temp control
      5. Cons: longer mobilisation time, long landing strip, requires road transport from landing area to hospital

Select Medical Team

1. Doctor – ED, intensivist, or anaesthetist
2. Nursing
3. Paramedic/s
4. Ambulance officer/s

Patient Preparation

Secure

1. Airway, ventilation, oxygenation
2. All catheters, tubes, drains
3. IV access (tape/splints as req) + extra access (min 2 large bore)

Sedation/Analgesia

1. Sufficient stock for increased req during transport
2. Prophylactic antiemetic (risk of vomiting from medication, condition, or motion)
3. Prophylactic anticonvulsant (if fitting risk)

IV Fluids

1. Ensure blood volume deficit corrected before transport
2. Ensure sufficient stock for transit
3. At altitude plastic bags distend & IV s often slow/stop so may need freq flushing

Injuries/conditions

1. C-spine stabilisation: special braces – avoid sandbags as mobile
2. Consider prophylactic ICC if any pneumothorax or >2 rib # as PTX expands at altitude
3. Use Heimlich valves rather than underwater drains for ICC
4. Haemorrhage controlled
5. Splint # preferably without air splints
6. Bivalve plasters prior to ascent

Environment

1. Temp likely to fall during transport (esp aircraft)
2. Core T monitoring
3. Incubators for neonates

Communication

1. Ensure patient, relatives, sending/receiving hospital teams all kept informed
2. Mobile phone / in-aircraft radio

Documentation

1. Notes, investigation results, XRs
2. In-transit notes/obs
3. Consider consent for transport due to increased risks

Equipment

1. Need defib, oxygen & suction.
2. Kit should be light, portable, and attachable to fixtures of vehicle/aircraft.
3. Alarms should be visible and audible.
4. Electronics: Battery containing and compatible with electrical system of vehicle/aircraft.
5. Monitors: ECG/cardiac, oximeter, ETCO2, NIBP (auto) or intra-arterial BP, thermometer
6. ETT: remove some air from cuff on ascent & re-instil on descent, humidification needed.
7. Ventilator: robust, know gas consumption (Oxylog: min vol + 800ml/min), sufficient O2
8. Drugs & fluids: Infusion or syringe (ideally) pumps, pre-packed syringes, full resus packs

Anticipated In-Transport Problems

Ideally preparation avoids need to deal with problems in transit.

Loading/unloading

1. Line-tube dislodgement, thermal insult, re-bleeding.

Altitude effects

1. In normal patients little effect of piO2 as SaHb>90% at alt<2500m.
2. However may have effect if piO2, [Hb]<75g/L, paO2, O2 req, fixed cardiac output
3. In severe respiratory disorders (e.g. ARDS) may not be able to maintain oxygenation at 100% FiO2 at altitude so fly at lower alt or increased pressurisation (ideally sea level).
4. Gas expansion: Volume doubles at 5000m. If not room for expansion then P in cavity.
5. Expansion relevant in:
   1. Patient (generally may CI air retrieval unless can fly at low cabin altitude)
      1. Fractured skull with aerocoele
      2. Penetrating eye injury
      3. Mediastinal emphysema, pneumothorax
      4. Recent gut sutures, bowel obstruction
      5. Decompression illness/air embolism
   2. Equip:
      1. IV bags
      2. ETT cuff
      3. Colostomy bag
      4. MAST suits
      5. Staff: sinuses, middle ear
   3. Solutions:
      1. Heimlich valve for ICC, vent cavities e.g. NGT, give 100% O2, deflate ETT cuff while at alt.
6. Temperature:
   1. Keep patient warm but ensure coverings don’t obscure patient/hamper access
7. Noise, vibration & G forces:
   1. Detrimental to recent vascular anastomoses or re-expanded PTX, unstable patients, comfort/pain level, haemostasis, IV insertion, auscultation, communication.
8. Positioning & Space:
   1. Ideally (but often impossible) in HI/ICP: head forwards on take-off, opp on landing. Space limitations for access, procedures.
9. Vital signs:
   1. Difficult to monitor due to noise/vibration, may need visual signs/alarms instead of audible ones. Monitor accuracy at altitude or with vibration.
10. Crash/Emergency landing:
    1. Trained crew
11. Other:
    1. Motion sickness, sinus/middle ear pressure, phobias (height, flying, enclosed spaces)