Reliability of extravascular lung thermal volume measurements by thermal conductivity technique in sheep.
J Appl Physiol (1985)
; 73(4): 1449-56, 1992 Oct.
Article
en En
| MEDLINE
| ID: mdl-1447090
ABSTRACT
We tested the accuracy, sensitivity, and reproducibility of a new lung water computer, based on the thermal conductivity technique, in 22 anesthetized closed-chest ventilated sheep with different treatments 1) controls (n = 8), 2) 0.05 ml/kg of oleic acid + 100 ml/kg of lactated Ringer solution (n = 6), and 3) airway instillation of saline [3.1 +/- 1.3 (SD) g/kg, n = 8]. After 4 h, we determined the extravascular lung water gravimetrically. We found a significant overall correlation between the final extravascular lung thermal volume and the gravimetric extravascular lung mass (P < 0.001). Although the average ratio of extravascular lung thermal volume to extravascular lung mass was 0.97 +/- 0.25 ml/g for all groups, the computer overestimated extravascular lung mass in controls by 10% (17 g) and underestimated it in sheep with oleic acid by 15% (95 g) and in sheep with airway instillation by 8% (37 g). The computer also underestimated the small quantities of saline placed via the airway in the alveolar space by 75% (61 g). Reproducibility of three consecutive measurements was 4.3% (SE). We conclude that the thermal conductivity technique has an ability to detect the baseline extravascular lung mass but has a poor ability to detect an accurate increment of the extravascular lung water under poor tissue perfusion in anesthetized ventilated sheep.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Conductividad Térmica
/
Mediciones del Volumen Pulmonar
Límite:
Animals
Idioma:
En
Revista:
J Appl Physiol (1985)
Asunto de la revista:
FISIOLOGIA
Año:
1992
Tipo del documento:
Article