| Question | Answer |
| Diffusion | Process of gas exchange. |
| Ventilation | Process of air movement into and out of the lungs. |
| Perfusion | Process of circulation of the blood through the lung tissues(capillary bed). |
| [ventilation problem]
Upper airway obstruction | [ventilation example]
Foreign body, epiglottis |
| [ventilation problem]
Lower airway obstruction | [ventilation example]
Asthma, airway edema |
| [ventilation problem]
Chest wall impairment | [ventilation example]
Trauma, muscular dystrophy |
| [ventilation problem]
Neurogenic dysfunction | [ventilation example]
Central nervous system (CNS)- depressant drugs, stroke |
| [diffusion problem]
Inadequate oxygen in ambient air | [diffusion example]
Fire environment, carbon monoxide (CO) poisoning |
| [diffusion problem]
Alveolar disorder | [diffusion example]
Lung disease,inhalation injury |
| [diffusion problem]
Interstitial space disorder | [diffusion example]
Pulmonary edema, near-drowning |
| [diffusion problem]
Capillary bed disorder | [diffusion example]
Severe artherosclerosis |
| [perfusion problem]
Inadequate blood volume or hemoglobin levels | [perfusion example]
Shock, anemia |
| [perfusion problem]
Impaired circulatory blood flow | [perfusion example]
Pulmonary embolus |
| [perfusion problem]
Capillary wall disorder | [perfusion example]
Trauma |
| For ventilation to occur, the following must be intact: | - Neurological control (to initiate ventilation)
- Nerves between the brain stem and the muscles of respiration
- Functional diaphragm and intercostal muscles
- Patent upper airway
- Alveoli that are functional and have not collapsed |
| For diffusion to occur, the following must be intact: | - Alveolar and capillary walls that are not thickened
- Interstitial space between the alveoli and capillary wall that is not enlarged or filled with fluid |
| For perfusion to occur, the following must be intact: | - Adequate blood volume
- Adequate hemoglobin in the blood
- Pulmonary capillaries that are not blocked
- Efficient pumping by the heart that provides a smooth flow of blood through the pulmonary capillary bed |
