The effect of gravity on mucociliary tracheal transport rates in fibrocystics and normals

J. W. Wong, N. Aspin, T. G. Keens

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The authors have reported a simple radioactive labelling technique developed in their laboratory for measuring the mucociliary tracheal transport rates (MTTR) in man in the upright position. Using the same method, the authors have studied MTTR in patients with cystic fibrosis (CF). The normals have a geometric mean MTTR of 3.6 mm/min, while the CF patients show a distribution of different clearance modes. In the fibrocystics, the authors have observed: Group 1 which shows clearance rates similar to the normals; Group 2 which has normal transport along with abnormalities such as cessations or reverse transport; and Group 3 which shows no transport. To establish the importance of gravity upon mucociliary clearance the authors have measured the MTTR in a group of subjects, first in the erect and second in the 25° head down position. The normal subjects showed no change in MTTR from the erect to the head down position. As for the CF patients, Group 1 showed no change in MTTR between the two positions, while Group 2 and 3 patients showed a dramatic change from abnormal or no transport in the erect position to positive MTTR in the head down position. The authors conclude that gravity has little effect on normal MTTR, but becomes important in cases of defective mucociliary clearance. This study shows that some CF patients have improved rates of mucus clearance during postural drainage.

Original languageEnglish (US)
Number of pages1
JournalAmerican Review of Respiratory Disease
Issue number4 (II)
StatePublished - Jan 1 1976
Externally publishedYes

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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