[Right-to-left shunt determination in dog lungs under inhalation anesthesia with rebreathing and non-rebreathing system].
OBJECTIVE
To investigatge right-to-left shunt determination in dog lungs under inhalantion anesthesia with non-rebreathing and rebreathing systems and fraction of inspired oxygen (F I O2) of 0.9 and 0.4, respectively.


METHODS
Two groups of 10 dogs each under inhalation anesthesia with sevoflurane: GI in which it was utilized non-rebreathing semiclosed system and F I O2 = 0.9, and GII in which it was utilized rebreathing semiclosed system and F I O2 = 0.4. The study parameters were: heart rate, medium arterial pressure, right-to-left intrapulmonary shunt, hematocrit, hemoglobin, arterial partial pressure of oxygen, mixed venous partial pressure of oxygen, mixed venous oxygen saturation, arterial partial pressure of carbon dioxide, partial pressure of water in the alveoli.


RESULTS
Shunt results were significantly different between the two groups - GI data were higher than GII in all the evaluated moments. Hence, the group with nonrebreathing (GI) developed a superior grade of intrapulmonary shunt when compared with the rebreathing group (GII). The partial pressure of water in the alveoli was significantly higher in GII.


CONCLUSIONS
The inhalation anesthesia with non-rebreathing system and F I O2 = 0.9 developed a higher grade of intrapulmonary right-to-left shunt when compared with the rebreathing system and F I O2 = 0.4. The higher humidity in GII contributed to the result.
Rosa
André Leguthe
AL
School of Veterinary Medicine, São Paulo Methodistic University, São Bernardo do Campo, Brazil.
Mota
Patrícia Cristina Azevedo
PC
Castiglia
Yara Marcondes Machado
YM
D000764:Anesthesia, Closed-Circuit; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D000818:Animals; D004285:Dogs; D005260:Female; D006813:Humidity; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage; D023421:Models, Animal; D010100:Oxygen / Q000008:administration & dosage*; D010101:Oxygen Consumption / Q000502:physiology; D011652:Pulmonary Circulation / Q000502:physiology*; D012121:Respiration, Artificial; D000077149:Sevoflurane; D013874:Thiopental / Q000008:administration & dosage
D018685:Anesthetics, Inhalation; D006993:Hypnotics and Sedatives; D008738:Methyl Ethers; D000077149:Sevoflurane; D013874:Thiopental; D010100:Oxygen