Rosalee Brown

The primary function of the pulmonary system is its exchange of gas. The lung, the primary organ of the lower respiratory tract, enables the body to obtain oxygen to carry out cellular metabolic functions and to remove carbon dioxide produced by these processes. The pulmonary system also plays a very important role in filtering and humidifying inspired air and participating in various immune functions. Many vital functions of the body depend on a properly functioning pulmonary system.

Optimal nutrition is important throughout the life cycle to promote proper development and functioning of the pulmonary system. Research and other evidence from famines have shown that malnutrition adversely affects the structure and function of the lungs. Pulmonary disease can in turn affect the nutritional status of an individual.

Energy intake

Usually, in pulmonary disease, energy needs can be greatly increased by 25 to as much as 50 per cent more than would be needed before the disease; this is usually caused in some diseases by both hyper-metabolism (increased energy use) and hyper-catabolism (increased muscle breakdown). Complications of the disease, the nature of the disease and treatment modalities may affect the intake and utilisation of energy and other nutrients to effectively counteract these conditions.

There are many pulmonary diseases which can affect individuals through the life cycle — diseases in the premature infant to those in the elderly. There are those which are categorised as primary, such as tuberculosis and bronchial asthma, and those which are secondary, for example the ones associated with cardiovascular disease or obesity.

Shellfish

There are some acute conditions of a pulmonary nature such as airway obstruction or anaphylaxis, caused from an adverse reaction to, for example, shellfish. The conditions which need nutrition management are the chronic conditions such as cystic fibrosis, chronic obstructive pulmonary disease and other such conditions which will not go away or will persist for a very long time.

These patients need individual assessment by a registered dietitian to determine their nutritional status and chart a course for their nutritional management which can change many times during the course of the disease. Nutritional management is only one part of the management, as the medical management, including pharmacological therapy, can influence nutritional care. Nutritional management is especially crucial in infants and children, as development can be impaired by insufficient energy and nutrients.

In many instances, patients cannot physically consume all the required calories needed because of distension, nausea and anorexia. These patients will need nutrition through enteral (tube feeding) route to increase the chances of improved intake and utilisation.

Nutrition is vital in the survival and improved health and well being of persons with pulmonary disease. The registered dietitian is an integral part of the medical team in managing these patients.