Evaluation of a combined transcutaneous carbon dioxide pressure and pulse oximetry sensor in adult sheep and dogs.
OBJECTIVE
To evaluate a combined transcutaneous carbon dioxide pressure (tcPCO(2)) and pulse oximetry sensor in sheep and dogs.


METHODS
13 adult sheep and 11 adult dogs.


METHODS
During inhalation anesthesia, for the first 10 minutes following sensor placement, arterial blood gas was analyzed and tcPCO(2) was recorded every 2 minutes. Subsequently, the animals were hyper-, normo-, and hypoventilated. The simultaneously obtained tcPCO(2) and PaCO(2) values were analyzed by use of Bland-Altman statistical analysis.


RESULTS
Mean +/- SD overall difference between tcPCO(2) and PaCO(2) 10 minutes after sensor application was 13.3 +/- 8.4 mm Hg in sheep and 8.9 +/- 12 mm Hg in dogs. During hyper-, normo-, and hypoventilation, mean difference (bias) and precision (limits of agreement [bias +/- 2 SD]) between tcPCO(2) and PaCO(2) values were 13.2 +/- 10.4 mm Hg (limits of agreement, -7.1 and 33.5 mm Hg) in sheep and 10.6 +/- 10.5 mm Hg (limits of agreement, -9.9 and 31.2 mm Hg) in dogs, respectively. Changes in PaCO(2) induced by different ventilation settings were detected by the tcPCO(2) sensor with a lag (response) time of 4.9 +/- 3.5 minutes for sheep and 6.2 +/- 3.6 minutes for dogs.


CONCLUSIONS
The tcPCO(2) sensor overestimated PaCO(2) in sheep and dogs and followed changes in PaCO(2) with a considerable lag time. The tcPCO(2) sensor might be useful for noninvasive monitoring of changes but cannot be used as a surrogate measure for PaCO(2).
Vogt
Rainer
R
Vetsuisse Faculty, Anesthesia Division, University of Zurich, Zurich, Switzerland.
Rohling
Roman
R
Kästner
Sabine
S
D000769:Anesthesia, Inhalation / Q000662:veterinary; D000818:Animals; D001785:Blood Gas Monitoring, Transcutaneous / Q000295:instrumentation / Q000662:veterinary*; D002245:Carbon Dioxide / Q000097:blood*; D004285:Dogs / Q000097:blood*; D005260:Female; D008297:Male; D010092:Oximetry / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D010100:Oxygen / Q000097:blood*; D012756:Sheep / Q000097:blood*
D002245:Carbon Dioxide; D010100:Oxygen