ANAESTHESIA - Caesarean Section Flashcards
Which physiological changes occur within the mother during pregnancy?
Increased blood volume
Increased cardiac output
Increased oxygen consumption
Reduced functional residual capacity of the lung
Decreased gastric emptying
Why do pregnant animals have an increased cardiac output?
Pregnant animals have an increased cardiac output to help deliver adequate blood flow to the developing foetuses, as well as to meet the increased metabolic demands
Why do pregnant animals have a reduced functional residual capacity of the lungs?
The feotuses within the uterus will put pressure on the diaphragm and reduce the functional residual capacity of the lungs, and the ability of the lungs to expand
These is an increased risk of hypoventilation
What is the significance of the decreased gastric emptying in pregnant animals under anaesthesia?
Decreased gastric empying increases the risk of regurgitation under anaesthesia even if the patient hasn’t eaten in a while as there is more likely to be food in the stomach due to the delay in gastric emptying
What are some of the key practical concerns regarding anaesthesia in a pregnant animal?
Increased risk of hypoventilation
Increased risk of regurgitation
Pressure on the caudal vena cava (resulting in decreased venous return and cardiac output)
Patient may be fatigued (due to parturition)
Patient may be dehydrated
Drug licensing
What is the significance of drug licensing in pregnant animals?
There are very few drugs licensed in pregnant animals so it is very important to get consent from owners to use drugs under the cascade
Which factors regarding the neonates should you be aware of during a Caesarean section?
Reliant on mothers oxygen suppy whilst in utero
Transplacental transmission of drugs
Neonates are less capable of metabolising and eliminating drugs
Require resuscitation
Should be returned to their mother as soon as possible
What pre-operative prep should you do prior to a caesarean section?
- Have all equipment ready, i.e. towels ready, suture to tie off the umbilicus etc.
- Make sure to have lots of people available
- Gain IV access
- IV fluids if indicated
- Pre-clip the dam before induction
- Premedication and pre-oxygenate with a mask
- Position the dam tilted slightly to the left
- Aim to begin surgery as soon as possible after induction
Which factors should you consider when choosing premedication drugs for a caesarean?
Try to use low doses and drugs with antagonists available
Which sedative could you choose for a caesarean section?
Sedation may not be required but if it is, use low dose medetomidine
Atipamezole can be used to reverse alpha 2 agonists
Which opioid could you choose for a caesarean section?
There is concern regarding using long lasting opioids due to the prolonged effect on the neonates due to transplacental transmission of the drug, so fentanyl would be a good choice as it is short acting
Naloxone can be used to reverse opioids
Which premedication drugs should you avoid in pregnant animals?
Benzodiazepines as they have a profound sedative effect on the neonates and the antagonist available is expensive and thus not kept in stock by many practices
Why is it so important to pre-oxygenate pregnant animals prior to anaesthesia?
The neonates are reliant on the mother’s oxygen supply so it is important to try and maintain her oxygenation
Which induction drug is preferable for a caesarean section?
Alfaxalone
However propofol is acceptable
How should you induce pregnant animals for a caesarean section?
Induce the patient in sternal recumbency and keep the patient in sternal and the head elevated up until the airway is protected (due to the high risk of regurgitation)
Which maintenance drug is preferable for a caesarean section?
Sevoflurane
However isoflurane is acceptable
Why is sevoflurane preferable for a caesarean section?
Sevoflurane allows for a smoother recovery so the patient is more aware and alert to start mothering her young
Which changes are you likely to see when monitoring anaesthesia for caesarean sections?
Elevated end-tidal CO2 (due to the increased risk of hypoventilation)
Rapid respiratory rate
Hypoxaemia
Hypotension
How can you manage the hypoxaemia?
Keep the patient on 100% O2 and make sure the anaesthesia isn’t too deep
How can you manage the hypotension?
Alter anaesthetic depth
Fluid bolus
Ephedrine
Which analgesia could you administer for a caesarean section?
Epidural (if you are capable)
Incisional line block
Intraperitoneal lavage (with local anaesthetic)
Post-operative long lasting opioid
Post-operative NSAIDs
What are the benefits of local anaesthetics for cxcv4fd£aesarean sections?
Local anaesthetics have very limited transplacental transmission
How do you carry out neonatal resucitation?
Clear fluid from the oral cavity and nares
Oxygen supplementation
Naloxone administration (to reverse opioids)
Atipamazole administration (to reverse alpha 2 agonists)
Dry the neonates
Warm the neonates
What can be indicated by bradycardia is new born neonates?
Hypoxia
What should you provide the mother in recovery?
Warm and comfortable
Introduce neonates as soon as possible
May require help to suckle
