Analgesia + anaesthesia in labour Flashcards
(25 cards)
Nerve roots of body and fundus of uterus
T10-L1
Nerve roots of cervix and birth canal
S2-S4
What is entonox?
50% oxygen
50% nitrous oxide
Benefits of entonox in labour
quick onset
relatively potent
Side effects of entonox
loss of control
nausea
vomiting
What is pethidine?
synthetic phenylpiperidine derivative
opioid
Pethidine dose in labour
1mg/kg up to 150mg IM
Maternal effects of pethidine
confusion
loss of control
sedation
nausea and vomiting
respiratory depression
pruritis
Foetal and neonatal effects of pethidine
readily crosses placenta by diffusion
HR variability changes after 40 mins
peak levels 2-3 hours
When is remifentanil PCA used in labour?
when epidural contraindicated
What is an epidural?
placement of pharmacologically active drugs into the epidural space to work on the sensory and motor nerves there
What is the epidural space?
potential space between ligamentum flavum and the dura mater
motor and sensory spinal nerves pass through epidural space
What is a spinal?
spinals go through to the dura
holes in dura can give rise to bad headaches
time of onset more rapid than epidurals
block more predictable
What is combined spinal epidural?
a regional anesthetic technique that combines the rapid onset of a spinal block with the prolonged analgesia and titratability of an epidural block
Epidural location
lumbar epidural for lower limb and low abdominal incisions
thoracic epidural for midline incisions and above
epidurals not used for upper limb and head and neck surgery
Borders of epidural space
superior = foramen magnum
inferior = sacral hiatus
anterior = posterior longitudinal ligament
posterior = ligamentum flavum
laterally = intervertebral foraminae
Why are spinals and combined spinal epidurals not placed above L2?
due to presence of solid spinal cord
below L1/L2 is the cauda equina
Advantages of epidural analgesia
excellent analgesia
continuous
avoids parenteral opioids and side effects
can be extended for anaesthesia for LSCS
improved pulmonary function
minimise pulmonary and venous thrombosis
decrease in cardiovascular complications
Disadvantages of epidural analgesia
complications - failure, post-dural puncture headache, nerve damage, total spinal, IV administration
can prolong labour - 2nd stage, instrumental
side effects - hypotension, pruritus, shivering, back ache, pyrexia, decreased mobility
Indications for epidural analgesia
maternal request
to permit augmentation of labour
pre-eclampsia
maternal disease
anticipated difficult airway (obesity)
anticipated difficulty getting rapid regional anaesthesia (obesity)
expectation of operative delivery - twins, malpresentation
cardiac disease - regurgitant valvular lesions
specific neuro conditions - AV malformation
Contraindications to epidural analgesia
absolute:
- patient refusal
- local anaesthetic allergy
- infection at insertion site
relative:
- hypovolaemia
- coagulopathy
- anatomical abnormalities
- systemic sepsis
- valvular heart disease
- neurological disease
- back problems
Location of epidural
L3/4
L4/5
Tuffier’s line –> at iliac crests
What medication can be used to raise blood pressure in a woman in labour/section?
phenylephrine
Caesarean section categories and time limits
Cat A - 20 mins
Cat B - 30 mins
Cat C - 75 mins
Cat D- 360 mins
Elective
