2010 BC Guide in Determining Fitness to Drive

Chapter 15: Respiratory DiseasesBACKGROUND15.1 About respiratory diseasesA number of respiratory diseases may interfere with the safe operation of a motor vehicle bycausing reduced oxygen flow to the brain and subsequent cognitive impairment, includingimpairments in attention, memory, decision making, and judgement. Respiratory diseases thatare most likely to affect cognitive functioning are those that are chronic in nature.This chapter focuses on one of the most prevalent respiratory diseases, chronic obstructivepulmonary disease (COPD). However, other respiratory diseases also have the potential toimpair driving due to reduced oxygen flow to the brain; where this is the case, the guidelines inthis chapter also apply to them.Chronic obstructive pulmonary diseaseCOPD refers to a group of diseases characterized by obstructed air flow such as emphysema andchronic bronchitis. Emphysema and chronic bronchitis frequently coexist and the term COPD isoften applied to individuals suffering from these two disorders.The level of general impairment caused by respiratory diseases is commonly described as mild,moderate, or severe, as described in the table below.Level ofImpairmentNormalNoneSymptomsPulmonary FunctionTesting 6 resultFVC > 80% ofpredicted andFEV1 > 80% ofpredicted, andFEV1/FVC x 100 >75% andDLCOsb > 80% ofpredictedNature of generalImpairmentNone6 FVC = Forced vital capacity; FEV1 = Forced expiratory volume in first second; FEV1/FVC x 100 = Using thepreviously selected values for FVC and FEV1, compute the ratio and express as percentage; D LCOsb = Single breathdiffusing capacity138