Pregnancy and Cesarean Section Flashcards
cardiovascular changes in pregnant animals
CO increases 30-50%
- heart rate
- stroke volume: increased blood volume, decreased vascular resistance (afterload)
- blood pressure unchanged
T/F RBC increase > plasma volume increase
False
plasma volume increase > RBC increase → decrease PCV
T/F aortocaval compression decreases venous return
True
pregnant patients have a decreased _______ reserve
cardiac
what is the progesterone effect on the the respiratory center
decreased PaCO2 - hyperventilation
≈ 30 mmHg at time of parturition
what is the cause of decreased pulmonary resistance in pregnant animals
progesterone → relaxation of bronchial smooth mm.
pregnant animals have a(n) increased/decreased functional residual capicity (FRC)
decreased
increased abdominal volume
GI changes in pregnant animals
delayed gastric emptying
increased gastric acidity
decreased lower esophageal sphincter tone
increased risk of reguritation/aspiration
causes of delayed gastric emptying
pressure from uterus
decreased gastric motility
increased progensterone
renal changes with pregnancy
increased GRF (increased CO)
decreased BUN and CREA
pharmacolic changes in the dam
decreased MAC
increased sensitivity to local anesthetics
pharmocologic considerations for the fetus
most drugs easily cross placenta
fetal drug metabolism is slow - immature hepatic microsomal enzyme system
what is the ideal drug protocol
maximize O2 delivery to fetus - maintain CO and oxygenation, avoid uterine contraction/vasoconstriction
minimize drug effects on fetus
sedative use in small animal
not recommended
- acepromazine & benzodiazepines - fetal depression*
- alpha 2 agonist - decrease CO*
T/F alpha 2 agonists are used routinely in mares despite increased uterine pressure and decreased O2 delivery to the fetus
True
which alpha 2 agonist may cause less of an increase in uterine tone compared to xylazine
detomidine
which sedative is commonly used with ketamine in large animals
benzodiazepines
how should opioids be given
administer to mom after pups out
can reverse pups as pull out
how long does fetal elimination of opioids take
2-6 days
which induction agent is preferred in small animals
propofol
rapid metabolism in neonates, may be used as CRI instead of ISO/SEVO
which other induction agents can be used
Alfaxalone - safe and effective for C-sections in dogs
Etomidate - induction/recovery may not be as smooth
T/F the use of ketamine in small animals is controversial but can be used safely in large animals
True
- small animals - increased mortality in K9 neonates*
- large animals - limited options for induction in US*
MAC in increased/decreased in pregnant patients
decreased
what are the side effects of inhailed anesthestics in pregnant animals
same
hypotension, hypoventilation
progesterone increases/decreases does requirements of local anesthetics
decreases
which local anesthetics are more likely to accumulate
Amides
lidocaine, bupivacaine
T/F it is safe to use NSAIDs during pregnancy
False - not recommened for use during pregnancy
which NSAID did not increase risk of abortion in mares with colic
Flunixin
how can fetal O2 delivery be maintain during anesthesia
maintain maternal BP and oxygenation
avoid - uterine contractiona and vascostriction: decrease fetal perfusion
underlying problems that need to be corrected in cases of emergency C-section
hypovolemia
hypoGLU
hypoCa
how long after membrane ruptured should foals be delivered
<30 min
almost none survive after > 90 min
horse dystocia is a ________
true emergency!
T/F anesthesia is required for both controlled vaginal delivery (CVD) and C-section
True
CVD usually attempted first
minimum database in non-emergent c-sections (generally dogs)
PCV/TP
Glucose
iCA
lytes
technique for small animal non-emergent c-section
pre-oxygenate for 5 min
+/- short acting opioid
propofol or alfaxalone induction
rapid control of airway
ISO/SEVO/DES in O2 maintenance
which local blocks may be considered in combination with GA in small animal c-section
lumbosacral epidural
line block
- lidocaine or bupivacaine - consider duration of action*
- for epidural - add morphine for prolonged analgesia*
what are some complications with epidurals
increased volume of epidural blood vessels and increased epidural fat
DECREASES epidural space and INCREASES cranial spread of drug
epidural drugs volume should be decreased by _____ in pregnant patients d/t increased cranial spread (hypotension)
epidural drugs volume should be decreased by ≈ 1/3 in pregnant patients d/t increased cranial spread (hypotension)
animals should be positioned carefully to avoid ____
aortocaval compression
small animal neonatal care
clear oropharynx (DONT SWING)
clamp and cut umbilicus
towel dry
reverse opioids (1-2 drops naloxone sublingually)
heat support
+/- O2 support
small animal analgesia
epidural with morphine (up tp 24 hours)
Mu opioid agonist once neonates delivered
acetaminophen for dogs (NO CATS!)
what should be monitored closely in large animals GA
PaCO2 and PaO2
hypoxemia and hypercapnia likely
which types of mechanical ventilation may be required in LA GA
PIP
PEEP
why might recovery be more difficult in LA GA
extra weight
exhaustion from labor
ligament laxity
locoregional anesthesia in small ruminants
line block
lumbosacral epidural
same considerations as small animals
locoregional anesthesia in large ruminants
paravertebral block (proximal or distal)
inverted “L” block
analgesia in horses
butorphanol - can reverse in foal if necessary
NSAIDs - not recommended during pregnancy and lactation
caudal epidural
analgesia in ruminants
opioids once neonate delivered
L-S epidural with morphine (small)
caudal epidural (cows)
NSAIDs - Rimadyl approved for 1 dose in lactating cows
