Monitoring During Transport

Fig. 18.2 Inside a paramedic ambulance.

Noise and daylight may render monitors and their alarms unreadable and inaudible. Ambulances rely on battery sources for electrical power. Consequently hospital-based equipment that needs alternating current (AC) can be used only with its own power source or an AC/DC converter.

Untoward occurrences do occur in up to 70% of transfers and are associated with equipment failure; acute deterioration of PaO₂/FiO₂ ratio is common and ventilator-associated pneumonia (VAP) is significantly increased (Everest and Munford 2009).

Hazards Associated with Air Transport

The hazards encountered with air transport depend to a degree on the mode of transport (helicopter or aeroplane) and can be summarised as follows:

Expansion of gas in closed cavities: as atmospheric pressure falls with increasing altitude, the volume occupied by gas rises; clinically this results in expansion of trapped gases. This exacerbates a pneumothorax. In addition air in a tracheal tube cuff is susceptible to these changes; either gently fill the cuff with physiological (0.9%) saline or continuously monitor the cuff pressure during altitude changes.
Fluid loss: a fall in atmospheric pressure can cause fluid to extravasate from the intravascular to the interstitial space, resulting in oedema, hypotension and tachycardia; in addition, the effects of dehydration can be exacerbated (Hinds and Watson 1996).
Increased altitude: associated with a fall in temperature.
Hypoxia: increasing altitude causes a fall in the partial pressure of oxygen, which can lead to a fall in alveolar oxygen and hypoxia.
Temperature control: heating in helicopters can be particularly difficult. In addition the patient may be exposed to the environment when being transferred to and from the aircraft.
Noise and vibration: may cause nausea, pain and motor dysfunction (Intensive Care Society 2011).
Visibility: may be limited; this together with the high ambient noise levels can make monitoring even more difficult; the patient visual alarms may be obscured (Intensive Care Society 2011).
Unfamiliar environment: can be stressful for the patient and staff.

PATIENT MONITORING EQUIPMENT REQUIRED FOR TRANSPORT

Determining what monitoring equipment should be taken will depend on the condition of the patient and the available resources on the mode of transport. Any equipment taken should be (Intensive Care Society 2011):

lightweight, yet durable and robust
mounted at or below the level of the patient
restrained, yet easily accessible
regularly checked
battery powered if electrical (with battery life display).

Ideally equipment should be standardised across critical care networks and have both audible and visual alarms. A small versatile portable monitor such as a Propaq (Fig. 18.3) is invaluable. Depending on what is required, recordings of ECG, oxygen saturation, non-invasive blood pressure, temperature, invasive pressures and capnography can be taken. Capnography is recommended as a mandatory requirement by the Intensive Care Society (2011).

Fig. 18.3 Propaq portable monitor.