Food Animal Drugs
Pregnant animal anesthesia
Pregnant animals have physiological changes that alter the anesthesia protocol and risks. Consider the following when developing your plan:
- the fetus gets extra blood flow and oxygen; maternal cardiac output needs to meet the demand
- pre/post oxygenate!
- assist ventilation
- maternal blood pressure is decreased by ~ 10% and circulating blood volume is increased by ~30%
- animals placed in dorsal recumbency may have uterine compression of the aorta and vena cava
- elevate the right hip to minimize the impact
- maternal decreased functional lung capacity and maternal+fetal increased oxygen consumption
- increased risk of maternal reflux and aspiration; hepatic function tests increased due to liver compression
- secure airway; have suction available
- maternal kidneys have increased blood flow and filtration rate
- maternal decreased epidural space, CSF volume and increased sensitivity to local anesthetics
- be extra careful in small ruminants
- most anesthetic drugs get to the fetus
- Epidural useful to decrease need
Drug impacts in the pregnant animal:
- Acepromazine – safe in low doses, long acting, no reversal agent
- Benzodiazepenes – tetraogenic in first trimester; “floppy baby syndrome” near term, nice in low doses, antagonist available
- Alpha-2s – NOT recommended, lots of side effects
- Opioids- fetal depression > maternal, nice in low doses, antagonist available
- fentanyl is hard on baby, morphine is slower to cross placenta, limited buprenorphine goes to baby but no reversal available
- Ketamine – higher neonatal mortality in puppies, increased uterine tone, no reversal; not recommended in small animals
- Propofol, alfaxalone – safe
- Inhalants -safe
- GG- safe
