Association of partial pressure of carbon dioxide in expired gas and arterial blood at three different ventilation states in apneic chickens (Gallus domesticus) during air sac insufflation anesthesia

作者：Pare Monique^*; Ludders John W; Erb Hollis N

来源：Veterinary Anaesthesia and Analgesia, 2013, 40(3): 245-256.

DOI：10.1111/vaa.12005

• air sac insufflation
• anesthesia
• birds
• carbon dioxide

Objective To test whether partial pressure of CO2 in expired gas (PECO2) predicts the partial pressure of CO2 in arterial blood (PaCO2) in apneic chickens during air sac insufflation anesthesia at three different ventilation states. Secondary objective: To determine the PECO2 at which apnea occurs during air sac insufflation anesthesia. Study design Randomized cross-over study. Animals Twenty-three healthy male white leghorn chickens. Methods Chickens were anesthetized via mask with isoflurane in oxygen and an air sac cannula was placed in the right abdominal air sac. Delivery of isoflurane in O2 was transferred from the mask to the air sac cannula. The birds were maintained at a surgical plane of anesthesia and apnea was induced by adjusting gas flow; the PECO2 at apnea was recorded. The birds were then paralyzed and gas flow was adjusted to achieve three different PECO2s in random order: 43mmHg (5.6kPa) [hypoventilation]; 33mmHg (4.3kPa) [normoventilation]; and 23mmHg (3.0kPa) [hyperventilation]. After maintaining the target expired isoflurane concentration (EIso; 1.85 or 1.90%) and PECO2 for 15minutes, arterial blood gas analysis was performed to determine the PaCO2. The chickens were euthanized at the end of the experiment. Results Based on Bland-Altman comparisons, PECO2 was not strongly associated with PaCO2 during the three ventilation states. The PECO2 at which apnea occurred varied {median (minimum, maximum): 35 (30, 48)mmHg [4.6 (3.9, 6.2) kPa]}. Conclusions Measured PECO2 cannot be used in a simple linear fashion to predict PaCO2 in birds during air sac insufflation anesthesia. The PECO2 at which apnea occurs during air sac insufflation anesthesia is not predictable. Clinical relevance Arterial blood gases should be used to monitor CO2 during air sac insufflation anesthesia to verify appropriate patient ventilation.

• 出版日期2013-5