16. Caesarean Section Flashcards
What is the difference btw scheduled C-section and Emergency C-section?
Sheduled; fast and stabled patients. ex. frenchie breeders knowing they need it
Emerg: unstable, potentially critical patients - dehydrated, exhausted, dec sympathetic response, hypocalcemia (milk fever), hypoglycemia, sepsis
Emerg are higher risk for regurg and aspiration pneumonia bc of lack of fasting
feline c-section are uncommon, but do occur when critically ill and often in a septic state
What physiologic changes occur with pregnancy?
Physologic anemia: PCV 30-35%, inc plasma V w/o inc in RCs
Inc Cardiac output: Inc Hr, stroke V, dec systemic vascular resistance
Dec O reserves - dec functional residual capacity, inc RR, dec tidal V, hyperventilation > hypocapnia (ETCO 30mmHg), inc O consumption (20%)
GIT changes: cranial displacement of stomach, delayed gastric emptying, inc gastric secretions, relaxed lower esophageal sphincter tone
What are some anticipated anesthetic complications with pregnancy?
hypotension, hypoxemia/hypoxia
hypoventilation and hypercapnia
regurg and aspiration pneumonia
Hypothermia
What happens with pregnancy and hypotension?
significantly effects uterine perfusion and fetal oxygenation
Causes of hypotension: anesthetic drugs, dehydration, intraop fluid losses, abdominal distension and patient positioning
Why might patient positioning matter?
aorto-caval compression syndrome
pregnant patients in dorsal recumebncy will have dec venous return and dec uterine perfusion
More significant in species w/ one fetus positioned centrally in abdomen over vena cava (ex. horse)
How do we tx hypotension during C-sections?
dec amount of inhalant anaesthetic
treat with crystalloids or colloids
DONT treat w/ vasoconstrictor = dec uterine perfusions (epinephrine, phenylephrine)
Dobutamine IV infusion - not very seen in private practice
What is hypoxemia and hypoxia
- Hypoxemia: decreased levels of oxygen present in the blood
- Minimize hypoxemia during induction and recovery
- Quick induction and intubation required
- Pre-oxygenate for 3 – 5 minutes
- Monitor SPO2 and provide supplemental O2 in recovery
- Hypoxia: decreased levels of oxygen delivered to the tissues
- Organ perfusion is important to maintain fetal oxygenation
during anesthesia - Maintain oxygenation (SPO2 > 95%)
- Maintain Blood Pressure (MAP > 60 mmHg
What is hypoventilation?
Patient position: sternal is best or dorsal recumbency with
elevated chest
* Avoid dorsal recumbency until in surgery
* Hypercapnia can cause decreased uterine perfusion
(Sympathetic Nervous System Stimulation)
* Manual or mechanical ventilation if needed
* Avoid high Peak Inspiratory Pressure (PIP) and use high RR
with low tidal volume instead
What is aspiration pneumonia, how can we tx?
In a study of 808 dams, 1% maternal mortality was seen post
operatively, of these dogs 56 % of deaths were attributed to
pneumonia (Moon et al., BSAVA pg. 366)
* Perioperative treatment: metoclopramide, omeprazole or
pantoprazole, maropitant (Cerenia)
* Intubate and secure the airway quickly
* Anticipate regurgitation
* Check oral cavity prior to extubation
* Suction and flush esophagus
* Minimal to no sedation on recovery
What is hypothermia
significant hypothermia should be anticipated
repro organs exposed to room air during procedure
uterus has lg blood vessels that cool patient rapidly
hypothermia will prolong recovery to nursing of neonates
What are some pharmacological considerations?
all anesthetic agents cross the placenta
minimize the use of sedatives in the premed as this will cause sedation, resp depression and CV depression in neonates post-operatively
Drugs given to dam will have a more pronounced and longer effect in the newborns
MAC reduction of 30% in pregnant animals
How are we premeding our pregnant patients?
no premed, if dalm is calm and cooperative but minimize patient stress
Opioid mu agonist (ex. hydro, methadone, fentanyl)
Avoid sedatives (dexmedetomidine, ace)
What do we use to induce pregnant animals?
propofol and alfaxalone can be used w/ similar effects - wait 10m after induction before removing puppies
Avoid benzodiazepines, can cause floppy infant syndrome, avoid ketamine
Risks associated w/ mask inductions using only inhalational anesthetic (stress, regurg, aspiration)
What are some possible intra-op analgesia to give?
opioids - if not in premed, the dam can receive an opioid once the puppies have been delivered. Ultra short acting mu opioid (ex. remifentanil(do not need a liver for this, processed in the blood) is ideal intra op, can be given b4 removal of puppies
Local blocks: incisional line block, splash block (bupivacaine or lidocaine)
How would a lumbosacral epidural be performed
1ml/5kg dose, but total V of the epidural should be dec to 50-75%
epidurals should only be performed by efficient, trained professionals
lidocaine is preferred due to shorter duration of action which allows the dam to be up and mobile quicker
Avoid morphine, effects last up to 24hrs
What are the negative effects of lumbosacral epidural?
sympathetic nerve blockage resulting in significant hypotension
post-op loss of function in hind limbs can cause stress and the patient may req a prolonged stay in hospital
How will we do post-op care for a C-section?
inadequate pain control can decrease milk prod
post op analgesia: mu agonist opioid and an NSAID
A single dose post op NSAID (ex. meloxicam) has no significant effects on the puppies
Ideally dam and puppies should be reunited and nursing ASAP
Post-op goal is to get mom and pups healthy and at home - dec stress, hospital acquired infections
What is the order of priority of neonat resuscitation?
needs to be a lg group of trained individuals to assist in neonate resuscitation after delivery or trained tech/vet supervising
WARMTH > Airway > breathing > Circulation > drugs
10% neonate mortality rates in C-sections and up to 20% in emerg C-sections
What neonate resuscitation supplies do you need?
- Warming device (incubator)
- Warm dry towels
- Bulb syringes
- Multiple O2 sources
- Cat-sized O2 masks
- Intubation supplies
(14-18 ga IV cath, ET tube 1 and 2) - 25 ga needles and 1 ml syringes
- Naloxone, epinephrine,
doxapram - Hemostats, suture
- Multi-colored collars
What are ways to warm up neonates?
avoid hypothermia and actively warm neonates
resuscitate w/ warm towels and replace towels as they cool
Warm water bottles, bair hugger
environmental temperature is important (32C incubator)
place in incubator or warm box until puppies can be reunited w/ dam
normal neonate temp (35-37.7C)
Why is getting that airway open important?
primary cause of neonate mortality is hypoxia - bradycardia is usually a response to hypoxia
remove any debris from neonate’s face
lower head to drain fluids from airway, clears own airyway by crying
bulb syringe can be used to gently suction nostrils and oropharynx
How can we get a neonate to start breathing?
breathing can be stimulated by gently rubbing neonate with a warm, dry towel
supplemental O2 with face mask if neonate is breathing
acupuncture point GV 26
RR is 10-18bpm in newborns - will settle into a more regular pattern over time
What is acupuncture point GV 26
midline btw upper lip and nose
Stimulates respiration, CV system and sympathetic nervous system
How can we intubate neonates?
If initial attempts to stimulate respiration is unsuccessful:
* Intubate using a 14–18-gauge IV catheter or ETT 2 mm
* Gentle intubation, difficult due to anatomy
* Ventilate gently, and watch chest for over inflation
* Use a low PIP (10 cmH2O)
* Ventilate at the RR of 30-40 Bpm
* Can try ventilation with a tight-fitting mask
Easy to plug up with mucous and will need to change frequently
For resuscitation and getting the blood flowing again, what should we do if there is no response in 15-20m?
bradycardia mos toften associated w/ hypoxia, cardiac compressions 100-120bpm
Stop resuscitation if there >15-20m
What drugs can we give to puppies if they are doing thrifty?
IV access via jug or umbilical vein
breathing: reverse any resp depressing drugs (naloxone sublingually), doxapram 1-2 drops
Circulation - epinephrine every 3-5m, do not use atropine
What are some neonate considerations post-delivery?
umbilical cord will need to be ligated and cleaned
treat hypoglycemia - dextrose by mouth or IV
reunite w/ dam ASAP, do not leave puppies alone w/ ataxic dam
How can we increase success of live puppies?
planned C-section is better than emergency
decrease anes. time
maintain uterine perfusion and oxygenation
train all staff on how to assist in neonate resuscitation
Dam awake and nursing quickly after surgery
have a quiet, stress-free area for recovery like an exam room or a covered cage w/ a towel and minimize interactions
