Pulmonary ventilation disorders, cough, dyspnea, and their interference with driving
Gas exchange depends on the balance between ventilation and blood flow and, therefore, diseases affecting cause respiratory failure.
Acute respiratory failure is caused in a short time period, while chronic respiratory failure measured at rest, breathing environment air and sustained over time, causes arterial hypoxemia with or without hypercapnia.
Hypoxemia can cause, in addition to dyspnea, state of confusion, malaise or even loss of conscience.
Ventilation disorders include:
- Obstructive such as asthma, chronic obstructive pulmonary disease, such as chronic bronchitis and emphysema, cystic fibrosis and bronchiolitis.
- Restrictive parenchymal, such as sarcoidosis, idiopathic pulmonary fibrosis, pneumoconiosis, and interstitial pneumopathies induced by drugs or radiation.
- Restrictive extraparenchymal due to weakness of the diaphragm, myasthenia gravis, Guillain-Barré syndrome, muscular dystrophies and injuries of the cervical spine or the chest wall for kyphoscoliosis, obesity and ankylosing spondylitis.
Advice on Pulmonary ventilation
- The patient with dyspnea must not drive.
- All pulmonary conditions associated with dyspnea are disabling for driving, and the physician should warn the patient about it.
- The patient where the treatment can balance ventilatory function without dyspnea can always drive provided the physician considers it appropriate and reports favorably about it.
- The disease causing paroxysmal dyspnea is disabling for driving, since the driver loses suddenly the control of the car, with risk of accident.
- If the patient learns to know his situation, knows how to control it from the start and the treatment stabilizes the clinical progression, he can drive as long the physician indicates it.
- The driver starting with dyspnea should park the car as soon as possible without forcing driving, and follow the recommendations given by his physician in case of dyspnea in his specific disease.
- If it does not improve, he cannot go to the emergency room driving, but he will ask for help and will wait calm and at rest, with the indications of his physician for the case of dyspnea.
- It is advisable that drivers where ventilatory function disorders can occur from their disease take inside the car, in a visible place, the medical report with the treatment and recommendations, to provide them to the emergency services.
It is the sudden expiratory maneuver, of explosive nature, that tends to remove the material present in the airways, that can be exhausting for the patient, preventing him from resting and to get to sleep.
The treatment of cough involves basically that of the underlying cause.
The most effective drugs are central-acting antitussives, such as codeine and dextromethorphan.
Codeine has antitussive, analgesic and slightly sedative effects, and can provoke nausea, vomiting, constipation and drowsiness.
High-dose dextromethorphan can depress breathing.
Demulcent and moisturizing or vaporizing aerosols smooth the irritated pharyngeal mucosa membrane and reduce the viscosity of bronchial secretions.
Central-acting antitussives, expectorants, antihistamines, mucolytics, decongestants, bronchodilators and proteolytic enzymes, are frequently mixed in many over-the-counter syrups.
Advice on Cough
- Some treated drivers consider that their improvement is slow and they often increase on their own the dose or number of administrations, suffering somnolence that, added to the lack of night rest for the cough, increases the risk of accident when driving.
- Our patients should be warned to follow the treatment guidelines indicated, and that, if they do not improve, they should visit us again to establish changes if necessary.
- Coughing fits while driving prevent from controlling the car and the environment, and can lead to an accident of serious consequences.
- In these circumstances the patient should be advised against driving until the clinical condition improves, for his safety and that of others.
- If cough is productive, when the driver feels that a coughing fit is near, he often is distracted to look for a paper or handkerchief where to expectorate, taking one or both hands off from the steering wheel and losing the control of the car for that time.
- In addition, during expectoration he uses the hands losing partially or completely the control of the car commands during that time.
- We should recommend these patients to perform short trips when driving, doing all stops in places free from accidents, to be able to expectorate without running risks.
The patient describes it as a troublesome feeling of difficulty to breath, that forces him to breath in with a greater muscle effort, in order to expand the chest cavity and be able to take out the air from the lungs.
The fatigue of the respiratory muscles causes a feeling of “chest tightening”.
The cause of dyspnea can be pulmonary, cardiac, circulatory, chemical, central, psychogenic, and paroxysmal nocturnal.
Patients with dyspnea of restrictive origin are usually well while resting, but suffer very acute dyspnea when performing physical exercise, approaching ventilation to the limit of their respiratory capacity.
In obstructive dyspnea, the increased ventilatory effort induces the appearance of dyspnea still at rest, and breathing is very hard and slow, particularly when breathing out.
For permitting driving, the severity of dyspnea is assessed, or if dyspnea can arise suddenly in a patient previously asymptomatic.
Advice on Dyspnea
- The patient who may suffer paroxysmal dyspnea of respiratory origin due to his disease, but knows how to recognize the onset of dyspnea and adopt the appropriate measures not to have an accident, can drive.
- There are unexpected urgent situations that originate dyspnea such as pneumothorax, and, if the patient is not warned, all that he can do is park the car immediately in a safe area and ask for help.
- The patient with dyspnea cannot drive.