antenatal and intrapartum analgesia Flashcards
outline the pain pathway in the 1st stage of labour
pain signals from uterine contractions and cervical dilation are carried via sensory nerves to T10- L1 spinal cord segment
outline the pain pathway in the 2nd stage of labour
pain from the distension of the perineum and the stretching of the pelvic ligaments is carried via the pudendal nerve to S2/S4
outline the pain pathway in the 2nd stage of labour
pain from the distension of the perineum and the stretching of the pelvic ligaments is carried via the pudendal nerve to S2/S4
List the dermatomes that need to be anaesthetised for the different procedures that may need to be performed during labour
Epidural for labour - T10-S4 trial of forceps - T5-S4 C/S - T5- S4 MROP - T6-S4 Cervical/vaginal repair.- S2-S4 perineal repair - S2-S4
what are 3 common misconceptions regarding the risk of epidural in labour?
No association with a prolonged first stage
No increased rates fo C/S
No long term back problems
List some common side effects of an epidural
opiate itch, shivering
what are 2 unfavourable obstetric outcomes associated with an epidural?
prolonged 2nd stage
increased instrumental delivery rates
List 2 Relative contraindications to regional anaesthesia
- Risk of significant haemorrhage
- h/o spinal surgery with spinal anatomical abnormalities
List 3 contraindications for regional anaesthesia:
- Coagulopathy (platelets <80, INR >1.4)
- Systemic infection due to risk of seeding infection
- Lack of trained staff to provide adequate care
Maternal refusal
Describe the cause of a post epidural headache
- Puncture of the dura mater allowing CSF to leak out of the vertebral canal
If the rate of leakage is greater than the rate of CSF production then the CSF volume will actually falling causing the headache
List 3 groups of women who are particularly at risk from a GA and explain why
- Women with PET - surge in BP from tracheal intubation can lead to intracranial haemorrhage
- Women with high BMI - higher risk of failed intubation and aspiration
Women with known airway difficulty - higher risk of failed intubation
- Women with high BMI - higher risk of failed intubation and aspiration
List 3 reasons why an anaesthetist might use general rather than regional anaesthetic?
- Multiple failed attempts at a regional block
- Contraindications to regional anaesthetics e.g. coagulopathy
Maternal refusal for regional analgesia
- Contraindications to regional anaesthetics e.g. coagulopathy
Describe the treatment options and evidence for post epidural headache
- Conservative - mild PDPH can be managed using bed rest and simple analgesia. Caffeine has been used classically however no high quality evidence for its use - patients who normally drink caffeine should be encouraged to do so as they otherwise may develop a caffeine withdrawal headache
Surgical - epidural blood patch - injection of a patients own blood through a needle into the epidural space - to create a clot that patches up the dural puncture.
List 3 complications of labour analgesia associated with obesity
- Multiple attempts at regional anaesthesia
- Higher rates of dural puncture
Epidural migration into fatty subcutaneous tissue
- Higher rates of dural puncture
What is the time frame required before regional anaesthesia is safe following:
Prophylactic dose clexane
12 hours
What is the time frame required before regional anaesthesia is safe following:
Therapeutic dose clexane - 24 hours
In a patient with PET what measures should be taken prior to regional anaesthetic placement?
- Platelet count in the last 6 hours in mild/moderate PET
- In severe PET - platelet count immediately prior to insertion
- If platelet count < 100 then coags should also be done
List 2 evidence based (Cochrane evidence) forms of analgesia in labour
- Epidural
- CSE
- Entonox
List 2 methods of analgesia that MAY work in labour (Cochrane evidence)
- water
- massage
List 2 methods of analgesia with inadequate evidence to make a judgment (according to Cochrane review) as to their efficacy in labour
- TENS
- Hypnosis
List 3 obstetric interventions that may reduce the risk of instrumental delivery during labour with an epidural?
- 1:1 midwifery support in labour
- oxytocinon augmentation
- passive decent for up to 2 hours in nulliparous - leads to fewer rotational and mid cavity instrumentals
- manual rotation
What is the evidence regarding maternal satisfaction associated with epidural pain relief in labour?
there is level 1 evidence that epidural and CSE are preferable to women when cf any other form of pain relief in labour
List one adverse outcome associated with epidural analgesia when cf systemic opiate use in labour?
- increases the 2nd stage slightly
List 5 benefits using epidural analgesia when cf opiate analgesia in labour?
- less nausea and vomiting
- more effective pain relief
- reduced risk of fetal acidosis
- reduced risk of neonatal naloxone
List an anaesthetic intervention that has been shown to reduce rate of instrumental delivery?
lower concentration of local anaesthetic in epidural
what is the risk with NSAID use in pregnancy?
- even short term use in the third trimester is associated with premature closure of the ductus arteriosus
a woman presents concerned that she has heard that Panadol use in pregnancy leads to childhood asthma, what would you tell her?
Retrospective epidemiological studies linking paracetamol use in pregnancy to later development of childhood asthma are inherently confounded (U); when adjusted for respiratory tract infections in the child the association is lost (Q) (Level III-2 SR)
List 3 interventions for low back and pelvic pain and indicate the evidence for these interventions
exercise - reduces low back and pelvic pain level 1 evidence
manual therapy - reduce intensity of pain when cf relaxation but not when cf sham intervention level 1 evidence
the use of pelvic support belt may reduce pelvic girdle pain (clinical expertise and expert opinion)
