Safe patient transfer is an integral part of patient care and can be classified as primary or secondary.1 Primary transfer is the initial movement of the patient from the scene of injury or illness to hospital and is commonly undertaken by paramedics and other pre-hospital specialists using land ambulance or helicopter. Secondary transfers occur between hospitals either for access to specialist care, repatriation or due to lack of bed space. The majority of secondary transfers are carried out by land ambulance but some occur by air, particularly for longer distances. Critically unwell patients are often accompanied by an anaesthetic or intensive care escort and transfer competencies are included in both the ICM and Anaesthesia curriculums in the UK.

It is estimated that around 11,000 critical care transfers occur annually in the UK.1 These are challenging for a multitude of reasons including the following:

They often involve unstable patients awaiting definitive treatment (e.g. neurosurgery).

They are often carried out by trainee doctors, out of normal hours and under time-pressure.

They rely on portable equipment including transfer ventilators and monitors, which staff are less familiar with and are sometimes less capable than their non-portable equivalents.

They expose the patient to physical factors (e.g. acceleration) which adversely affect physiology and can lead to patient deterioration.

Considering their challenging nature, it is not surprising that in a prospective study in the Netherlands, adverse events occurred in 34% of secondary transfers and 70% of these were thought to be preventable.2 It is therefore essential that staff undertaking transfers have appropriate knowledge, training and equipment to undertake them safely and this is highlighted in national guidelines by the Intensive Care Society and Association of Anaesthetists of Great Britain and Ireland.1, 3 The transfer of patients by air can occur by helicopter or fixed wing aircraft, both of which present different problems. The transfer of patients by air is more challenging than land and should only be carried out by staff with appropriate aeromedical training, usually a dedicated specialist team.1

The following sections discuss in detail the physical factors associated with land and air transfer, the physiological effects they have on the patient and how anticipating these effects must be integrated with decision-making.