ABSTRACT
Haemoglobin in red blood cells (erythrocytes) is necessary for the uptake of oxygen in the lungs, and its transport and transfer to peripheral tissues. e normal haemoglobin level is 13.5-17.5 g/dL for males and 11.5-15.5 g/dL for females. Anaemia is not in itself a diagnosis but may be a consequence of a wide variety of disorders and it is important to determine the cause. Whatever the aetiology, cardiovascular reserve could be impaired and this could pose a problem in an aircra cabin with a pressure altitude of up to 8000 . With regard to passengers, subjects with a haemoglobin level of 7.5 g/dL or more are not likely to experience problems with commercial air travel. However, the haemoglobin level alone cannot be relied upon to decide whether a patient is t to travel. A distinction must also be made between chronic and acute anaemia. Patients with long-standing
anaemia, such as that associated with renal failure, oen have good cardiovascular compensation and experience few problems with travel. By contrast, patients with anaemia of recent onset, such as aer surgery, are more likely to experience problems. Chronic anaemia may precipitate angina in subjects with an already compromised circulation. e Canadian Cardiac Society Guidelines recommend a haemoglobin level of 9 g/L as a threshold value below which travel is inadvisable in passengers who have undergone coronary artery bypass graing (Ross et al. 2004). Signs of haemodynamic instability precipitated by exertion include tachycardia or other arrhythmias, hypotension, chest pain and changes in the ST segment of the electrocardiogram. In addition to possible diculties associated with the journey, travellers with anaemia should be advised of the possible hazards of blood transfusion in developing countries (see below). is is particularly important for patients with chronic haematological conditions where periodic transfusion is required. When assessing potential passengers for tness to y, it is also important to bear in mind that examination whilst at rest may prove misleading and exercise tolerance should be assessed. As a general guideline, those who are able to walk about 50 metres and to climb 10-12 stairs without symptoms should be able to y without incident.
