16 - Respiratory Diseases

16.1About respiratory diseases

Overview

A number of respiratory diseases may interfere with the safe operation of a motor vehicle by causing reduced oxygen flow to the brain and subsequent cognitive impairment, including impairments in attention, memory, decision making and judgement.

Respiratory diseases that are 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 obstructive pulmonary disease (COPD).  However, other respiratory diseases also have the potential to impair driving due to reduced oxygen flow to the brain; where this is the case, the standards in this chapter also apply to them.

Chronic obstructive pulmonary disease

COPD refers to a group of diseases characterized by obstructed air flow, such as emphysema and chronic bronchitis.  Emphysema and chronic bronchitis frequently coexist and the term COPD is often 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 of Impairment Symptoms Pulmonary Function Testing* result Nature of General Impairment
Normal None

FVC > 80% of predicted, and

FEV1 > 80% of predicted, and

FEV1/FVC x 100 > 75%, and

DLCOsb > 80% of predicted
None
Mildly Impaired Dyspnea when walking quickly on level ground or when walking uphill; ability to keep pace with people of same age and body build walking on level ground, but not on hills or stairs

FVC 51 to 59% of predicted, or

FEV1 41 to 59% of predicted, or FEV1/FVC x 100 41 to

59%, or

DLCOsb 41 to 59% of predicted.
Usually not correlated with diminished ability to perform most jobs
Moderately Impaired Shortness of breath when walking for a few minutes or after 100m walking on level ground

FVC 51 to 59% of predicted, or

FEV1 41 to 59% of predicted, or FEV1/FVC x 100 41 to

59%, or

DLCOsb 41 to 59% of predicted.
Progressively lower levels of lung function correlated with diminished ability to meet the daily demands of many jobs
Severely Impaired

Too breathless to leave the house, breathless when dressing.

The presence of untreated respiratory failure.

FVC 50% or less of predicted, or

FEV1 40% or less of predicted, or

FEV1/FVC x 100 > 40% or less, or

DLCOsb > 40% or less of predicted.
Unable to meet the physical demands of most jobs, including travel to work

(*FVC = Forced vital capacity; FEV1 = Forced expiratory volume in first second; FEV1/FVC x 100 = Using the previously selected values for FVC and FEV1, compute the ratio and express as percentage; DLCOsb = Single breath diffusing capacity)

16.2Prevalence

Estimates from the World Health Organization indicate that 80 million people have moderate to severe COPD.  Chronic bronchitis affects individuals of all ages.

Emphysema is more common among elderly individuals.  In Canada men have a higher rate of COPD (6.3%) than women (5.2%).  COPD increases in prevalence with age for both men and women with the highest prevalence for men over the age of 75 (9.1%).

16.3Respiratory disease and adverse driving outcomes

There have been no studies that examine the relationship between respiratory diseases and adverse driving outcomes.

16.4Effect on functional ability to drive

Condition Type of driving impairment and assessment approach* Primary functional ability affected Assessment tools
COPD or other respiratory disease Persistent impairment: Functional assessment

Cognitive

May also result in general debility

Medical assessments

Functional Assessment

(*See Part 1 for a discussion of the use of functional assessments for driver licensing decisions)

Research indicates that drivers with COPD are at risk of cognitive impairment due to chronic hypoxemia. For those with cognitive impairment, the impairment tends to be greater for more complex and demanding cognitive tasks. This cognitive impairment may affect a driver’s functional ability to drive.

Drivers with COPD also may develop general debility resulting in a loss of stamina required to support the functions necessary for driving.

Older drivers with COPD are more at-risk for functional impairment because they may experience:

  • age-related declines in blood flow to the brain
  • disease-related declines in arterial oxygen content, and
  • both age and disease-related declines in physical activity which can exacerbate deconditioning.

16.5Compensation

Drivers with COPD may be able to compensate for their functional impairment by using supplemental oxygen.

16.6Guideline for assessment

16.6.1 Mild impairment

National Standard All drivers eligible for a licence
BC Guidelines RoadSafetyBC will not generally request further information
Conditions for maintaining licence None
Reassessment RoadSafetyBC will not re-assess, other than routine commercial or age-related re-assessment
Information from health care providers Pulmonary function testing result or statement that the level of impairment resulting from the respiratory disease is mild
Rationale Mild impairment due to respiratory disease is unlikely to cause significant impairment of the functions needed for driving

16.6.2 Moderate impairment - Non-commercial drivers

National Standard Non-commercial drivers eligible for a licence
BC Guidelines RoadSafetyBC will not generally request further information
Conditions for maintaining licence None
Reassessment RoadSafetyBC will re-assess every 5 years, or as recommended by the treating physician, unless routine age-related re-assessment applies
Information from health care providers Pulmonary function testing result or statement that the level of impairment resulting from the respiratory disease is moderate
Rationale Moderate impairment due to respiratory disease is unlikely to cause significant impairment of the functions needed for non-commercial driving.  Reassessment is required to monitor for an increase in impairment that may affect ability to drive

16.6.3 Severe impairment - Non-commercial drivers

National Standard

Non-commercial drivers eligible for a licence if

  • a functional assessment indicates sufficient functional ability
BC Guidelines
  • If further information is required, RoadSafetyBC may request
    • a Driver’s Medical Examination Report; or
    • additional information from the treating physician
  • If the treating physician indicates possible impairment of one or more of the functions necessary for driving, RoadSafetyBC may request
    • functional assessment(s) as appropriate for the type(s) of impairment and class of licence held, unless there has been no significant change in the individual’s condition or functional ability since a previous functional assessment
  • If an ICBC driver examiner recommends further assessment, RoadSafetyBC may request
  • additional information regarding the individual’s medical condition, and/or an assessment from an occupational therapist or driver rehabilitation  specialist
Conditions for maintaining licence None
Reassessment RoadSafetyBC will typically re-assess every 2 years or as recommended by the treating physician
Information from health care providers
  • Results of functional assessment
  • Pulmonary function testing result or statement that the level of impairment resulting from the respiratory disease is severe
  • Whether the driver has insight into the impact their condition may have on driving
Rationale Severe impairment due to respiratory disease may cause significant impairment of the functions needed for driving, including cognitive impairment.  Licensing decisions should be based on an individual functional assessment

16.6.4 Requiring supplemental oxygen - Non-commercial drivers

National Standard

Non-commercial drivers eligible for a licence if

  • a road test while using supplemental oxygen indicates sufficient functional ability, and
  • the conditions for maintaining a licence are met
BC Guidelines
  • If further information is required, RoadSafetyBC may request
    • a Driver’s Medical Examination Report; or
    • additional information from the treating physician
  • RoadSafetyBC may request an ICBC road test, unless there has been no significant change in the individual’s condition or functional ability since a previous functional assessment
  • If an ICBC driver examiner recommends further assessment, RoadSafetyBC may request
    • additional information regarding the individual’s medical condition, and/or an assessment from an occupational therapist or driver rehabilitation  specialist
Conditions for maintaining licence No conditions are required
Restrictions

RoadSafetyBC  will impose the following restriction on the licence of an individual who is found fit to drive

  • 51   May drive only when using supplemental oxygen
Reassessment RoadSafetyBC will typically re-assess every 2 years or as recommended by the treating physician
Information from health care providers
  • Pulmonary function testing result or statement that the level of impairment resulting from the respiratory disease requires supplemental oxygen
  • Whether the driver has insight into the impact their condition may have on driving
  • History of compliance with prescribed treatment regime
  • If known or applicable, whether the driver is compliant with any current conditions of licence
Rationale Drivers who require supplemental oxygen due to respiratory disease may have significant impairment of the functions needed for non- commercial driving, including cognitive impairment.  Licensing decisions should be based on an individual functional assessment, including ability to drive while using supplemental oxygen

16.6.5 Moderate impairment - Commercial drivers

National Standard

Commercial drivers eligible for a licence if

  • a functional assessment indicates sufficient functional ability
BC Guidelines
  • If further information regarding an individual’s medical condition is required, RoadSafetyBC may request
    • a Driver’s Medical Examination Report, or
    • additional information from the treating physician
  • RoadSafetyBC may request an ICBC road test, unless there has been no significant change in the individual’s condition or functional ability since a previous functional assessment
  • If an ICBC driver examiner recommends further assessment, RoadSafetyBC may request
    • additional information regarding the individual’s medical condition, and/or an assessment from an occupational therapist or driver rehabilitation  specialist
Conditions for maintaining licence None
Reassessment RoadSafetyBC will re-assess in accordance with the schedule for routine commercial  re-assessment
Information from health care providers
  • Functional impairment, if any
  • Pulmonary function testing result or statement that the level of impairment is moderate
  • Whether the driver has insight into the impact their condition may have on driving
  • History of compliance with prescribed treatment regime
Rationale Moderate impairment due to respiratory disease may cause significant impairment of the functions needed for driving. Licensing decisions should be based on an individual functional assessment

16.6.6 Severe impairment or requiring supplemental oxygen - Commercial drivers

This guideline applies to commercial drivers who require supplemental oxygen while at rest.

National Standard

Commercial drivers not eligible for a licence

BC Guidelines RoadSafetyBC will not generally request further information
Conditions for maintaining licence N/A
Reassessment N/A
Information from health care providers N/A
Rationale Severe impairment or a requirement for supplemental oxygen due to respiratory disease generally indicates significant impairment of the functions needed for commercial driving