More nose functions
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TLC, or total lung capacity is measured two ways, helium dilution technique, or using pressure measurements taken during body plethysmography. Neither testing method is significantly impacted by airflow. In the PFT lab, VC is measured through the mouth with nose clipped, with a forced breath out then back in. The volume measured is not necessarily flow dependent because the subject continues to exhale until no more flow is detected on spirometry. The residual capacity, RC, or amount of air left in the lungs after complete exhalation is calculated using the TLC minus the VC.
I think you are correct in that your overall respiratory function is nose dependent. And that is something not generally considered in the pulmonary function lab. Consider that the nose makes sure inspired air reaches the lungs at body temperature and at 100% humidity, and provides a back pressure to the lungs on exhalation that is beneficial to gas exchange. The senses including temperature and smell in the nose can cause involuntary physiologic responses. So, maybe there is an avenue for clinical study to learn more about how the nose plays into respiratory-related disease. Maximum ventilatory volume (MVV) is a test used to understand the extent of air obstruction or restriction, and is done with the nose clipped and the patient hyperventilating for one-minute. But, as mentioned in my prior post, both established tests for measuring nasal obstruction and nasal restriction in the nasal passages has not panned out to clinical utility.
TLC, or total lung capacity is measured two ways, helium dilution technique, or using pressure measurements taken during body plethysmography. Neither testing method is significantly impacted by airflow. In the PFT lab, VC is measured through the mouth with nose clipped, with a forced breath out then back in. The volume measured is not necessarily flow dependent because the subject continues to exhale until no more flow is detected on spirometry. The residual capacity, RC, or amount of air left in the lungs after complete exhalation is calculated using the TLC minus the VC.
I think you are correct in that your overall respiratory function is nose dependent. And that is something not generally considered in the pulmonary function lab. Consider that the nose makes sure inspired air reaches the lungs at body temperature and at 100% humidity, and provides a back pressure to the lungs on exhalation that is beneficial to gas exchange. The senses including temperature and smell in the nose can cause involuntary physiologic responses. So, maybe there is an avenue for clinical study to learn more about how the nose plays into respiratory-related disease. Maximum ventilatory volume (MVV) is a test used to understand the extent of air obstruction or restriction, and is done with the nose clipped and the patient hyperventilating for one-minute. But, as mentioned in my prior post, both established tests for measuring nasal obstruction and nasal restriction in the nasal passages has not panned out to clinical utility.
posted by nawledge at
10:37 PM
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