Respiratory function can be affected during dental treatment. Dentists need to be aware if their patients have any respiratory conditions especially as most treatment takes place in the airway. Medication used for treatment of chronic obstructive respiratory disease should be considered when planning dental treatment. Some drugs used in dentistry, sedatives, narcotics and large doses (taking into consideration patients' age and physical status) of local anaesthetics are capable of producing transient respiratory depression.

Patients with a history of asthma may have an acute episode during treatment. A pre-operative assessment should consider the treatment needed if an attack occurs. Patients are usually well informed about emergency treatment and often carry an inhaler prescribed for such an emergency.

An increasing number of dental surgeries are equipped with oxygen and oximeters. The stress of treatment on patients with chronic obstructive pulmonary disease can be reduced with supplemental oxygen. These patients need to be placed in a position of comfort, without being too far reclined. A nasal mask or canula delivering 2-3 litres of oxygen per minute readily increases peripheral oxygen saturation to above 96%, providing improved physiological conditions for dental anaesthesia and improved patient comfort during the procedure. It can be shown that an additional supplement of one litre per minute of nitrous oxide (a mixture of 75-80% oxygen) improves physiological function and in particular heart rhythm, should minor irregularities in rhythm be present.

Unless there is a specific contraindication, adrenaline or other catecholamine vasoconstrictors can be used in dental local anaesthetics. Respiratory disease itself is not a contraindication to the use of catecholamine vasoconstrictors.

If there is any doubt concerning treatment of these patients, the physician managing their pulmonary condition should be consulted and treatment jointly managed.

R. G. Woods

Associate Professor, Australian Dental Association