ABSTRACT
After the age of 30 years, changes associated with ageing begin to develop, progressively affecting every organ and bodily system. The lungs become less elastic, and atelectasis can begin to occur even when the patient is sitting or standing, as the closing volume (the volume at which areas of collapse appear within the lungs) increases and encroaches upon normal functional lung volumes. This effect is exacerbated by general anaesthesia and lying down. Responses to hypoxia and hypercapnia are reduced, and protective airway refl exes are attenuated. Cardiac pacemaker activity and responsiveness decline, contributing to the generation of arrhythmias. Atrial fi brillation is particularly common in the elderly, and is regarded by some as a ‘default rhythm’ triggered by stress. Even without overt vascular disease, the vascular tree becomes ‘stiffer’, resulting in higher blood pressure and increased cardiac workload. This leads to left ventricular hypertrophy, predisposing to heart failure. Renal and liver function deteriorate. Cerebral blood fl ow is reduced, and parts of the brain are subject to atrophy. Confusion can become more common, particularly after surgical intervention. Muscle mass declines, and the metabolic rate generally decreases.
