TY - JOUR
T1 - Inhaled carbon dioxide causes dose-dependent paradoxical bradypnea in animals anesthetized with pentobarbital, but not with isoflurane or ketamine
AU - Ginosar, Yehuda
AU - Nachmanson, Nathalie Corchia
AU - Shapiro, Joel
AU - Weissman, Charles
AU - Abramovitch, Rinat
N1 - Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/10/1
Y1 - 2015/10/1
N2 - Introduction: In spontaneously breathing mice anesthetized with pentobarbital, we observed unexpected paradoxical bradypnea following 5% inhaled CO2. Methods: Observational study 7-8 week CB6F1/OlaHsd mice (n= 99), anesthetized with 30 mg/kg intraperitoneal pentobarbital. Interventional study: Adult male Wistar rats (n= 18), anesthetized either with 30. mg/kg intraperitoneal pentobarbital, 100. mg/kg intraperitoneal ketamine or 1.5% isoflurane. Rats had femoral artery cannulas inserted for hemodynamic monitoring and serial arterial blood gas measurements. Results: Observational study: There was a marked reduction in respiratory rate following 4 min of normoxic hypercapnia; average reduction of 9 breaths/min (p<0.001) (17% reduction from baseline). Interventional study: increasing CO2 caused dose-dependent increase in respiratory rate for ketamine-xylazine (p=0.007) and isoflurane (p=0.016) but dose-dependent decrease in respiratory rate for pentobarbital (p=0.046). Increasing inspired CO2 caused dose-dependent acidosis following pentobarbital and isoflurane (p=0.013 and p=0.017, respectively); but not following ketamine-xylazine (p=0.58). Conclusions: Inhaled CO2 caused paradoxical dose-dependent bradypnea in animals anesthetized with pentobarbital, an observation not hitherto reported as a part of anesthesia-related respiratory depression.
AB - Introduction: In spontaneously breathing mice anesthetized with pentobarbital, we observed unexpected paradoxical bradypnea following 5% inhaled CO2. Methods: Observational study 7-8 week CB6F1/OlaHsd mice (n= 99), anesthetized with 30 mg/kg intraperitoneal pentobarbital. Interventional study: Adult male Wistar rats (n= 18), anesthetized either with 30. mg/kg intraperitoneal pentobarbital, 100. mg/kg intraperitoneal ketamine or 1.5% isoflurane. Rats had femoral artery cannulas inserted for hemodynamic monitoring and serial arterial blood gas measurements. Results: Observational study: There was a marked reduction in respiratory rate following 4 min of normoxic hypercapnia; average reduction of 9 breaths/min (p<0.001) (17% reduction from baseline). Interventional study: increasing CO2 caused dose-dependent increase in respiratory rate for ketamine-xylazine (p=0.007) and isoflurane (p=0.016) but dose-dependent decrease in respiratory rate for pentobarbital (p=0.046). Increasing inspired CO2 caused dose-dependent acidosis following pentobarbital and isoflurane (p=0.013 and p=0.017, respectively); but not following ketamine-xylazine (p=0.58). Conclusions: Inhaled CO2 caused paradoxical dose-dependent bradypnea in animals anesthetized with pentobarbital, an observation not hitherto reported as a part of anesthesia-related respiratory depression.
KW - Anesthesia
KW - Animals
KW - Carbon dioxide ventilatory response
KW - Control of respiration
KW - Respiratory rate
UR - http://www.scopus.com/inward/record.url?scp=84934291238&partnerID=8YFLogxK
U2 - 10.1016/j.resp.2015.06.003
DO - 10.1016/j.resp.2015.06.003
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C2 - 26099799
AN - SCOPUS:84934291238
SN - 1569-9048
VL - 217
SP - 1
EP - 7
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
ER -