Airway thermal volume in humans and its relation to body size

Vladimir B. Serikov, E. Heidi Jerome, Neal Fleming, Peter G Moore, Frederick A. Stawitcke, Norman C. Staub

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The objective of this study was to investigate the influence of volume ventilation (VE) and cardiac output (Q) on the temperature of the expired gas at the distal end of the endotracheal tube in anesthetized humans. In 63 mechanically ventilated adults, we used a step decrease in the humidity of inspired gas to cool the lungs. After change from humid to dry gas ventilation, the temperature of the expired gas decreased. We evaluated the relationship between the inverse monoexponential time constant of the temperature fall (1/τ) and either VE or Q. When VE was increased from 5.67 ± 1.28 to 7.14 ± 1.60 (SD) 1/min (P = 0.02), 1/τ did not change significantly [from 1.25 ± 0.38 to 1.21 ± 0.51 min-1, P = 0.81]. In the 11 patients in whom Q changed during the study period (from 5.07 ± 1.81 to 7.38 ± 2.45 1/min, P = 0.02), 1/τ increased correspondingly from 0.89 ± 0.22 to 1.52 ± 0.44 min-1 (P = 0.003). We calculated the airway thermal volume (ATV) as the ratio of the measured values Q to 1/τ and related it to the body height (BH): ATV (liters) = 0.086 BH (cm) - 9.55 (r = 0.90).

Original languageEnglish (US)
Pages (from-to)668-676
Number of pages9
JournalJournal of Applied Physiology
Issue number2
StatePublished - Aug 1997


  • Cardiac output
  • Conductivity
  • Heat exchange
  • Lung capacity
  • Lung mass
  • Lungs
  • Noninvasive measurement
  • Temperature
  • Ventilation

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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