Intensive Care Medicine

, Volume 30, Issue 7, pp 1491–1494 | Cite as

Mucociliary function deteriorates in the clinical range of inspired air temperature and humidity

  • Emma Kilgour
  • Nigel Rankin
  • Stuart Ryan
  • Rodger Pack
Brief Report



To test whether a reduction in air temperature within the clinical range [37 °C to 30, 100% relative humidity (RH)] altered mucus transport velocity (MTV) and ciliary beat frequency (CBF) in an in vitro ovine tracheal model.


Controlled laboratory study.


University research laboratory.


Farm-reared sheep.


Tracheae were mounted flat in an organ bath. Krebs Henseleit bathed the serosal surface and air at 100% (RH) was passed over the mucosal surface at 4 l/min. Cilial beat frequency (CBF) was measured photo-electrically and mucus transport velocity (MTV) by timing movement. After 2 h at 37 °C (100% RH) the tissue was either maintained with those settings (controls), or the air temperature reduced to 34 °C or 30 °C. Tissue was taken for histology before and after each experiment.

Measurements and results

CBF was 19.8±2.7 beats/s and MTV 5.7±2.6 mm/min in tissue exposed to air at 37 °C. Cilial activity continued for up to 6 h in the controls but mucus transport was more fragile. Reduction of the air temperature to either 34 °C or 30 °C led to a decrease in both CBF and MTV and, frequently, total mucociliary failure. There was a reduction in epithelial mucous cell numbers in all preparations. Tissues exposed to low temperature had additional abnormal histology.


Delivery of inspired gas at 30 °C, or even 34 °C, with 100% RH may not be sufficient to prevent epithelial damage occurring during 6 h exposure.


Sheep Trachea Humidification Mucosa Epithelium 


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Emma Kilgour
    • 1
  • Nigel Rankin
    • 2
  • Stuart Ryan
    • 3
  • Rodger Pack
    • 1
  1. 1.Institute of Food Nutrition and Human HealthCollege of Sciences, Massey UniversityPalmerston NorthNew Zealand
  2. 2.Department of Intensive Care MedicineMiddlemore HospitalAucklandNew Zealand
  3. 3.Respiratory GroupFisher & Paykel HealthcareAucklandNew Zealand

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