Exam 4: Lecture 30 - Anesthesia for C-sections, neonates, and geriatrics Flashcards
what increases physiologically during pregnancy
- increase CO due to increase HR and stroke volume
- blood and plasma volume
- minute ventilation due to increase RR
- oxygen consumption (~20%)
- intragastric pressure
- renal plasma flow and GFR
what decreases physiologically during pregnancy
- Hb and PCV
- plasma protein
- PaCO2
- tidal volume, functional residual capacity and total lung capacity
- total pulmonary resistance and peripheral vascular resistance
- GI motility, gastric emptying, and gastric pH
- BUN and creatinine
what happens to venous return during pregnancy
may be decreased when placed dorsally due to compression of vena cava by gravid uterus resulting in decrease CO and hypotension
why does relative anemia happen during pregnancy
maternal blood volume increased about 20% with larger increase in plasma volume
T/F: a normal range PCV in a pregnant bitch may mean she is dehydrated
true!
there is __1___ myocardial work and __2__ cardiac resistance in pregnancy
- increased
- reduced
T/F: pregnancy increased alveolar ventilation and reduced FRC results in an increase in MAC requirements
FALSE! Decrease/reduced MAC
T/F: being pregnancy makes them prone to hypoxemia
true
when is a c-section considered an emergency
- patient has been in active labor for > 1 hr with no fetus delivered
- may be in compromised metabolic state
- viability of puppies a concern due to increased mortality for dam and fetuses
when is a C-section planned
- gestation length known
- during normal hours…. plenty of help
- patient is fasted
what breed is common to have dystocia
brachycephalic breeds
what is important to ask in the history for a pregnant dam
how long have they been in labor and if any puppies have been delivered (dead or alive)
what is a normal fetal HR
150-200bpm
what is an abnormal fetal HR that means they are stressed
100-150bpm
what bloodwork should we do for c-sections
PCV/TS, BUN, Ca, glucose, electrolytes
what stabilization should we do prior to performing a c-section
- correct fluid deficits and electrolyte imbalances
- potentially blood type and cross match
- shave abdomen and dirty scrub prior to induction
- induce in OR
- have puppies/kittens out within 5-10 mins
what meds should we consider for c-sections to help reduce esophageal reflux
cerenia - reduces nausea and vomiting
or
metoclopramide or famotidine
what is the MINIMUM time for pre-oxygenation prior to induction for a c-section
5 mins with 100% O2
what are the 2 schools of thought for premeds for c-sections
- avoid giving premeds to promote viable fetuses
- administer opioid for sedation and analgesia so induction and maintenance amounts are decreased
T/F: we should avoid drugs that cause vomiting when doing anesthesia for a c-section
true
drugs that are highly _______ bound do not readily cross the placenta
protein bound
what are the benefits and disadvantages of opioids as premeds for c-sections
benefits - sedation and analgesia, can be reversed
disadvantages - dose dependent respiratory depression and bradycardia in dam and fetuses
why is the use of atropine controversial for c-sections
because it crosses placenta and can lead to O2 consumption by the fetuses
why is glycopyrrolate a good anticholinergic for c-sections
does not cross the placenta
what are the benefits of benzodiazepines for premed during c-section
- mild sedation and skeletal muscle relaxation
- midaz is water soluble and shorter duration than diazepam
- can antagonize with flumazenil after delivery
what are the disadvantages of benzodiazepines for premed during c-section
- can cause respiratory depression
- fetal livers do not metabolize due to immature enzyme systems so they get prolonged sedation
T/F: phenothiazines are recommended for a predmed for a c-section
FALSE! Not recommended
T/F: alpha-2 agonists are not recommended for c-sections
true! due to increased chance of puppy mortality
T/F: xylazine has an oxytocin like effect on the uterus
true
what are the considerations for inductions during a c-section
swiftly securing the airway via intubation and cuff inflation reduces risk of aspiration occurrence
what are the disadvantages of “masking down”
- takes longer than injectables
2.inhalation induction is more rapid in pregnant animals bc of decreased functional reserve and increase minute volume - stress and catecholamine release = fetal stress
- hypoxemia in dam and fetuses
- risk of regurg and aspiration from unprotected airway
what are the characteristics of propofol as an induction agent for c-section
- metabolized in liver and crosses placenta
- causes hypotension due to vasodilation
- respiratory depression may need IPPV
- provides no analgesia
- not cumulative
is propofol acceptable for induction for a c-section
yes!!
T/F: alfaxalone for c-section in the dog has similar puppy survival rates to propofol
true
T/F: ketamine + diazepam can be used in c-sections
true!
what are the benefits and disadvantages of ketamine and diazepam for induction for c-section
- ketamine causes less CV depression in dams, but significant depressant effects in neonates
- decreased likelihood of puppies breathing spontaneously at birth with use of ketamine
- midazolam can be substituted for diazepam
what drug is the induction agent of choice for dams with pre-existing cardiac disease
etomidate!!
T/F: all inhalants cross placenta
true! due to lipid solubility and low molecular weight
T/F: we should keep inhalants as low as possible to avoid neonatal respiratory depression
true!
__1___ or _____2___ may be needed due to pressure on diaphragm from uterus
- manual ventilation
- mechanical ventilation
why should we avoid hyperventilation in c-sections
because maternal hypocapnia is associated with decreased uterine and umbilical blood flow and increased maternal affinity for hemoglobin leading to fetal hypoxemia
what type of local anesthesia can we use for c-section
- line block with lidocaine or bupivacaine
- TAP block
- epidural anesthesia
what should we use to monitor a patient undergoing a c-section
- indirect blood pressure with doppler and sphygmomanometer
- ECG
- pulse ox
- temp
- capnography
- arterial blood gas analysis
what is the biggest complication of anesthesia during a c-section
hypotension
when should we treat hypotension during a c-section
if MAP is below 60 mmHg or systolic below 80mmHg
what are the positive inotropes that can be used during a c-section
- ephedrine
- dobutamine and dopamine
how do we manage newborns
- must clear oropharyngeal cavity
- delivery ASAP of pups
- rub newborn vigorously to stimulate breathing and movement
- supplement O2 with mask or in O2 chamber
- analeptics such as doxapram can be used to stimulate respiration
- acupuncture at GV-26
- naloxone
what age is considered a neonate
up to 4-6 weeks
what age is considered pediatric
6-12 weeks
__1___ is mostly HR dependent so avoid ______2___
- cardiac output
- bradycardia
T/F: airway obstruction, hypoventilation, and hypoxemia can occur because tissue O2 demand is 2-3x higher
true!!
what age are hepatic and renal systems functional in neonates/pediatrics
around 8 weeks it is fully functional
because the hepatic and renal systems are not fully functional until 8 weeks, what drugs should we avoid
drugs with extensive metabolism or reduce dose
T/F: neonates have poor thermoregulatory ability so you should have warming devices ready
true!!
what 2 drugs should we AVOID for pre-med in pediatric patients
acepromazine or alpha-2 agonists
opioids may cause respiratory depression and bradycardia….what drug should we have ready to be used
naloxone!!
________ lasts longer than atropine and less likely to produce sinus tachycardia
glycopyrrolate
T/F: geriatric patients require a thorough history, PE, and minimum database prior to anesthesia
true!!!
___1___ drug doses and use of __2____ drugs than can be antagonized are preferred for geriatric
- lower drug doses
- short-acting drugs
T/F: you should plan for O2 supplementation and IPPV for anesthesia for geriatric patients
true
we should be careful using what before, during, and after anesthesia for geriatric patients
careful titration of IV fluids
T/F: we should quickly treat hypotension with a positive inotrope in geriatric patients
true!!
what positive inotropes can we use in geriatric patients to treat hypotension
dopamine or dobutamine
____ is NOT a disease!!
age!!
