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The mainstay of our birthing suite work is the provision of epidural analgesia for the pain of labour. The Cochrane group describes the more likely effects and side-effects of the technique.
http://www.cochrane.org/reviews/en/ab000331.html
Epidurals for pain relief in labourEpidurals are widely used for pain relief in labour. There are various types, but all involve an injection into the lower back. The review of trials showed that epidurals relieve pain better than other types of pain medication, but they can lead to more use of instruments to assist with the birth. There was no difference in caesarean delivery rates, long-term backache, or effects on the baby soon after birth. However, women who used epidurals were more likely to have a longer second stage of labour, need their labour contractions stimulated, experience very low blood pressure, be unable to move for a period of time after the birth, have problems passing urine, and suffer fever. Further research on reducing the adverse outcomes with epidurals would be helpful.
The less frequent complications include headache, intrathecal overdose, intravenous toxicity, infection and neuropathy.
Advising a patient in labour about these things can be vexed.
Paech M. Just put it in!" Consent for epidural analgesia in labour.
Anaesth Intensive Care. 2006 Apr;34(2):147-9.
We try to minimize and avoid side-effects and complications by technique and dosage:
Motor block is minimised by the addition of lipohilic opioid (usually fentanyl). Intermittent bolus (by PCEA or staff) also reduce local anaesthetic use. Ropivacaine is not as potent as racemic bupivacaine.
In
practice, 15 ml of bupivacaine 0.1 – 0.125%, or ropivacaine 0.1 –
0.2% ropivacaine with fentanyl 2 – 5 µg/ml will be effective
for first stage analgesia. Such a dose is effective in the majority,
and will be not catastrophic if is accidentally injected into the
intrathecal space or a blood vessel. At MHW, 0.1 % bupivacaine is
then infused at 10 ml/h. Higher concentrations and doses may be
required for a dysfunctional labour or second stage labour, but
should only be injected after careful appraisal of an initial small
dose (10mg bupivacaine) to ensure that the catheter is not misplaced. Adrenaline containing test doses are not warranted if analgesia is to be achieved with these non-toxic doses.
CSE has become more popular in recent years. The usual induction dose is 1 – 2.5 mg bupivacaine with fentanyl 10 – 25 µg fentanyl. CSE’s main advantage is its rapid onset of analgesia. Its debated disadvantages are pruritis, hypotension and fetal bradycardia, and possibly a greater risk of infective and traumatic complications.
The recently published Cochrane review (which had authors from Mercy Hospital for Women) was sanguine about the merits of CSE:
http://www.cochrane.org/reviews/en/ab003401.html
Combined spinal-epidural versus epidural analgesia in labour
Simmons SW, Cyna AM, Dennis AT, Hughes D
There appears to be little basis for offering CSE over epidurals in labour with no difference in overall maternal satisfaction despite a slightly faster onset with CSE and less pruritus with epidurals. There is no difference in ability to mobilise, obstetric outcome or neonatal outcome. However, the significantly higher incidence of urinary retention and rescue interventions with traditional techniques would favour the use of low-dose epidurals. It is not possible to draw any meaningful conclusions regarding rare complications such as nerve injury and meningitis.
A systematic review published in the British Medical Journal in June, 2004, came to a similar conclusion.
Know your equipment and how to use it.
The ANZCSA policy PS 14 Guidelines dor the Conduct of Major Regional Analgesia in Obstetrics should be known and followed.
For example, the Portex kit popular in Melbourne has an 18 G tuohey needle and a 20 G catheter that has 3 lateral foramina in the terminal 1.5 cm. The catheter attaches to a hub that is not meant to occlude it. This in turn attaches to a 0.22µm filter. The infusion mixture should be stringently prepared with asepsis, filters and double-checking of drugs if a proprietary formulation is not used.
Avoid infection and be vigilant for it.
Reynolds F Infection as a complication of neuraxial blockade.
Int J Obstet Anesth. 2005 Jul;14(3):183-8.
The epidural should be inserted with strict asepsis; the epiduralist and assistants should be masked to cover both mouth and nose. Hands should be free of jewellery and watches. Skin prep solutions (alcoholic chlorhexidine is preferred over povidone iodine) should not contact the equipment or analgesic solution.
RA techniques should aim to limit the extent and duration of motor block so any deficits can be soon identified.
Intrathecal injection should always be at the lower lumbar interspaces. The long atraumatic spinal needles have been implicated in injuries to the conus medullaris and nerve roots. Obstetric palsies can involve lumbosacral nerves, and are typically unilateral. Some unilateral palsies are due to nerve root lesions.
Bilateral and caudal motor deficits require aggressive investigation (MRI) and possible emergency intervention in the case of space-occupying haematoma or abscess.
Accidental dural puncture may be minimised by some variations in technique (lateral position, saline, continuous plunger pressure, paramedian, etc). If ADP does occur, the chance of PDPH may be reduced by intrathecal catheter, crystalloid infusions and autologous blood injection through the catheter, although the reported success of these treatments varies. Epidural blood patch remains the most accepted treatment, typically at least 24 hours (said to avoid delivery associated bacteraemia, and for the torn dura to be more adherent of the patch) after the ADP.
Differential diagnoses of headache should be considered in cases of postpartum headache.
Ng K, Parsons J, Cyna AM, Middleton P
Compared to epidural, spinal anaesthesia allows surgery to begin earlier, but increases the need to treat hypotension. There was no difference shown with respect to failure rate, need for additional intraoperative analgesia, conversion to general anaesthesia intraoperatively, maternal satisfaction, and neonatal intervention. Differences in side-effects such as post dural puncture headache, nausea and vomiting, and postoperative complications needing anaesthetic intervention were inconclusive due to the small numbers reported. No studies reported breastfeeding ability and time to ambulation post surgery.
The National Institute for Clinical Excellence in the UK published guidelines for caesarean section in April 2004 (http://www.rcog.org.uk/index.asp?PageID=694). The guidelines for anaesthesia for CS include:
Pregnant women having a CS should be given information on different types of post-CS analgesia so that analgesia best suited to their needs can be offered .
Women who are having a CS should be offered regional anaesthesia because it is safer and results in less maternal and neonatal morbidity than general anaesthesia. This includes women who have a diagnosis of placenta praevia.
Women who are having induction of regional anaesthesia for CS should be cared for in theatre because this does not increase patient anxiety.
Women who are having a CS under regional anaesthesia should be offered intravenous ephedrine or phenylephrine, and volume pre-loading with crystalloid or colloid to reduce the risk of hypotension occurring during CS.
Each maternity unit should have a drill for failed intubation during obstetric anaesthesia.
To reduce the risk of aspiration pneumonitis, women should be offered antacids and drugs (such as H2receptor antagonists or proton pump inhibitors) to reduce gastric volumes and acidity before CS.
Women having a CS should be offered antiemetics (either pharmacological or acupressure) to reduce nausea and vomiting during CS.
General anaesthesia for emergency CS should include preoxygenation, cricoid pressure and rapid sequence induction to reduce the risk of aspiration.
Intravenous ephedrine or phenylephrine should be used in the management of hypotension during CS.
The operating table for CS should have a lateral tilt of 15°, because this reduces maternal hypotension.
“Single shot” spinal anaesthesia is typically be done with 10 - 12 mg hyperbaric bupivacaine and 10 - 15 µg fentanyl. A non-cutting (e.g. Whitacre) needle of at least 25G should be used the reduce the incidence of PDPH.
Smaller spinal doses of bupivacaine can be used if an epidural catheter is also passed, and this may be desirable in the complicated case where the rapid onset of high thoracic sympathetic blockade is a disadvantage.
For CS following labour where a epidural with dilute LA and opioid is already in place, anaesthesia can usually be achieved with 15 ml 2% lignocaine with adrenaline 5 µg/ml alkalinised with 1.5 ml of 8.4% NaHCO3. Alkalinisation hastens onset and improves the intensity of anaesthesia, particularly in the sacral segments. Freshly mixed lignocaine and adrenaline has a higher pH.
In emergencies, the choice of anaesthesia depends on the urgency to expedite to delivery and the maternal condition:
Levy reviewed anaesthesia for emergency caesarean section in Anaesthesia 2006 Aug;61(8):786-91. Review. I take issue, however, with his choice for topping up an in situ epidural catheter. Like Whittaker et al in Nov 2006 Anaesthesia, I choose alkalinised and adrenalised 2% lignocaine in this situation.
The assessment of a sensory level continues to vex authors and practitioners alike. (S. Yentis Height of confusion: assessing regional blocks before caesarean section. International Journal of Obstetric Anesthesia, Volume 15, Issue 1, Pages 2-6)
The more recent literature indicates a level at and including T5 to light touch is desirable, but this has been disputed in the correspondence sections. Certainly the level is high thoracic, rather than low thoracic; a loss of pinprick at T6 may not ensure anaesthesia for the duration of caesarean section.
When
GA is used, one should have a prepared failed intubation drill. How
a failed intubation is managed will depend on the maternal and fetal
circumstances. Awakening the patient with a view to awake intubation
or regional anaesthesia should be considered. The laryngeal mask
airway has evolved as a useful tool in the failed intubation
scenario. The proseal LMA seems even more suited to the obstetric
patient, and guiding it with an oesophageal gum elastic bougie results in a very high rate of successful placement.
Anaesthetic considerations in pre-eclampsia
pre-labour/delivery assessment by an obstetric anaesthetist
Analgesia by the lumbar epidural route provides good control of hypertension and improves uteroplacental blood flow and gives reliable blood pressure control and good operating conditions for operative delivery
Spinal anaesthesia with appropriate attention and judicious administration of vasopressors for hypotension is also suitable in most cases of pre-eclampsia
Regional anaesthesia is contraindicated in the presence of coagulopathy and in most cases of fetal distress requiring immediate delivery.
No level predictive of complications
Withholding RA may put the patient at a considerable disadvantage of inferior analgesia or risks of GA.
Coagulation unlikely to be disturbed if platelets . > 100000
Large series of epidurals at counts of 80000 + without haematoma
50000 – 75000 a grey zone: need to clinically evalulate. Many authors regard < 50,000 as too low.
There may be less risk with a spinal needle alone compared to a epidural needle and catheter.
Post-anaesthesia vigilance for haematoma is imperative.
Premature labour
Preeclampsia
Breech presentation
Haemorrhage
Caval compression
CSE with lower dose spinal may be useful for CS
Recognition and management of maternal cardiac disease in pregnancy.
Br J Anaesth. 2004 Sep;93(3):428-39. Epub 2004 Jun 11. Review.
Multi-disciplinary collaboration
RA not necessarily contraindicated, but smooth (slow) and stable conditions required.
Some centres have published case series of low dose spinal (e.g. 5 mg bupivacaine and fentanyl) CSE
Spinal/epidural catheter anaesthesia or opioid based GA have been used.
High rate of complicated obstetrics
Coexistent disease
RA difficulties
GA/airway difficulties
Early placement of epidural catheter is advisable. Secure with care
Ranitidine.
Position carefully on “ramp”
Consider:
Arterial line
Awake intubation
CSE
Spinal catheter
Beware catheter dislodgement and kinks. A 16G kinks less than an 18G.
Recent, dramatic case report (Anaesthesia, Dec 06) describes the use of local anaesthetic infiltration after failed intubation and unsuccessful placement of RA in a morbidly obese parturient with a distressed fetus.
If bleeding: usually GA with appropriate airway security and attention to induction drugs and doses.
Avoid/minimise volatile agent
BIS monitoring should be used if available
Not-bleeding: RA acceptable, but consider epidural catheter for what can be a long case
Most prefer GA if accreta (which is more likely with repeats)
Preparation: IV x2, blood, assistance, line to blood bank and lab, etc.
Ready resort to vasopressors, PFGF2a, hysterectomy,
angiographic
embolisation has been used effectively but presents the challenges of anaesthesia in the remote location.
-
Rapid infusion device
Invasive pressure monitoring
Lateral position if prepartum
aortic compression,
PGF2a
Minimising use of volatile agents
keeping warm
early resort to delivery & hysterectomy
The use of recombinant factor VII is increasing in obstetric haemorrhage and has seemed beneficial in many cases. However the evidence base and even consensus opinion remains scant.
Obstetric haemorrhage is more likely with:
Placenta praevia, accreta, especially with previous caesarean section,
Multiple pregnancy
Obstructed labour -> atony
uterine fibroids,
placental abruption or
previous third-stage complications.
Usually not an absolute contraindication to RA. Pregnancy and it’s end can change the course of neuromuscular disease, so RA can be an unfortunate coincidence. Published case reports and case series are usually reassuring with respect to neurologic exacerbation despite the concerns of LA neurotoxicity on fragile nerves. Some are concerned about spinal anaesthesia in multiple sclerosis, but dilute epidural LA with opioid seems to be appropriate. However the patient and the anaesthetist may still have understandable reservations about using RA. Preanaesthesia counselling is important. There may be a place for MRI before RA.
Neurological disease brings the risk of double crush insult to nerves subjected to needles and local anaesthetic.
Horlocker (Anesth Analg. 2006 Jul;103(1):223-8,) concludes “the risks commonly associated with neuraxial anesthesia and analgesia in patients with preexisting CNS disorders may not be as frequent as once thought and that neuraxial blockade should not be considered an absolute contraindication within this patient population”.
But with peripheral disease (Anesth Analg. 2006 Nov;103(5):1294-9): The risk of severe postoperative neurologic dysfunction in patients with peripheral sensorimotor neuropathy or diabetic polyneuropathy undergoing neuraxial anesthesia or analgesia was found to be 0.4% (95% CI 0.1%-1.3%). Clinicians should be aware of this potentially high-risk subgroup of patients when developing and implementing a regional anesthetic care plan”.
For a patient with, for example, multiple sclerosis I would choose to use low dose dilute epidural (not CSE) solutions in labour, and levobupivcaine (rather than lignocaine and adrenaline) for top-up for casearean section. For an elective CS in an MS patient I would use spinal anaesthesia with a low dose of bupivacvaine and fentanyl, and use epidural levobupivacaine for top-ups as required.
Spinal disease and previous surgery is not necessarily a contraindication, but difficulty to identify spinal anatomy and to achieve an adequate drug spread is more likely to occur.
Choice of technique will be influenced by respiratory and airway factors, and sensitivity to neuromuscular blockers. Suxamethonium may be contraindicated in the evolving neuromuscular syndrome.
Like the parturient with abnormal clotting, the patient with sepsis is a difficult one to draw a line where RA is contraindicated.
In general, the literature is reassuring of using RA in the presence of a septic focus if antibiotics have been recently given and the patient is not hypotensive, hypovolaemic or clearly unwell. The literature tackles the issue of intradural needle versus epidural catheter ad nauseam. However the consequences of neuraxial infection are extreme so the RA should be clearly of benefit, be preceded by broad-spectrum antibiotics and postprocedural vigilance is required.
The most common cause of infection in the parturient is chorioamnionitis. There is an antibiotic regimen recommended by “Therapeutic Guidelines”.
What is usually more relevant is how the septic patient will tolerate high sympathetic blockade. Thus for the overtly unwell parturient for CS, GA is usually the choice of anaesthesia. Such patients will not usually be allowed to labour anyway.
The parturient with pneumonia is suitable for RA, though care is needed with thoracic level blockade and its effect on ventilation and cough.
Low molecular weight heparins are increasingly used to reduce foetal loss as well as for thromboprophylaxis. The LMWHs are renally secreted, so renal impairment (which often exists in the at-risk perinatal patient) may prolong Factor X activity.
.
The guidelines below indicate the difference in management if the LMWH is therapeutic or prophylactic.
Suggested guidelines for regional anaesthesia and levels of consensus (MJA 2001; 175: 258-263).
• Regional anaesthesia (epidural or spinal block) is contraindicated during anticoagulation therapy because of the increased (although unquantified) risks of spinal haematoma17 (C1).
• If a regional anaesthetic is desired in women who require anticoagulation therapy, an elective delivery will allow for a planned reduction in dose or a change to intravenous unfractionated heparin (UH) (C1).
• Therapeutic subcutaneous injections of low molecular weight heparins (LMWH) or UH should be ceased at least 24 hours, and preferably 36 hours, before regional anaesthesia (epidural or spinal block) (C1).
• Intravenous UH (used to permit a rapid return of the APTT to normal after cessation of the infusion) should be discontinued at least six hours, and preferably 12 hours, before regional anaesthesia (C1).
• In women receiving prophylactic LMWH, an interval of more than 20 hours from the last dose should allow the placement of a regional block with minimal risk of complications (C2).
• A normal activated partial thromboplastin time (APTT) does not ensure minimal anticoagulant effect of LMWH, and the platelet count should be determined to exclude heparin-induced thrombocytopenia (C2).
• If caesarean section is being undertaken, further doses of LMWH should be delayed for at least four hours after placement of an uncomplicated regional block, and longer if the regional block has been complicated (C1).
• Low-dose LMWH therapy can be continued after delivery if there have been no complications in the siting of the regional block.17
• An epidural catheter can be removed 12-20 hours after a prophylactic dose of LMWH, and the next injection should be delayed by at least four hours after removal (C1).
• Women should be closely monitored postpartum for any symptoms or signs of spinal haematoma, in particular for numbness and weakness in the lower limbs, severe back pain, and bladder or bowel incontinence (C1).
Thrombocytopaenia
The platelet count and its relationship to platelet function tests is vexed.
Most authors thus express caution to perform RA less than 50 - 100 platelets.
Sophisticated tests are rarely an option in the acute obstetric setting.
Fine spinal needles are arguably better than thick epidural catheters in the borderline case.
Post-procedural vigilance is mandatory so to detect any intraspinal haematoma.
The parturient with a bleeding disorder (e.g. vonWillebrand Disease)
Von Willebrand’s disease affects approximately 1 in 1000 people, and is the most common
bleeding disorder seen in obstetric practice. Diagnosis is usually made after presentation for
excessive bruising, profuse bleeding from cuts or menorrhagia.
Von Willebrand’s disease is mostly due to either a deficiency (type I, the most common) or an
abnormality (type IIa and type IIb, or variant) of von Willebrand Factor (VWF). VWF is a
glycoprotein which both facilitates platelet adhesion and carries Factor VIII.
The main concerns for the parturient are
the risk of peripartum bleeding and
the risk of spinal/epidural haematoma from regional analgesia/anaesthesia.
Fortunately, pregnancy increases plasma levels of VWF and FVIII, so delivery is usually
uneventful. However, levels of these factors fall after delivery so postpartum haemorrhagic
complications may still occur.
Consultation with a haematologist before delivery is important because the type and severity
of VWD will determine the nature of prophylaxis and treatment before delivery, surgery and
anaesthesia. In particular, DDAVP will usually be beneficial in Type I VWD, but will be
ineffective in Type IIa or sometimes harmful in Type IIb.
If a parturient with a clinical history of VWD or a “bleeding disorder”
has not had antenatal consultation with a haematologist before presenting in labour or for
caesarean section, the following investigations should be performed in addition to FBE and
blood group typing.
VWF Ag
Factor VIII activity
VWF (ristocetin cofactor)
The normal range for these tests is 50 – 200%.
Note that APTT has poor sensitivity and specificity for identifying VWD.
The availability of DDAVP and Factor VIII should be determined, and haematology
consultation should be sought if factor levels are abnormal.
VWD and suitability for spinal/epidural injection
It is not possible to correlate a laboratory test value with a probability of neuraxial
haematoma due to spinal/epidural injection. The decision to proceed with such procedures should be
individualised according to the clinical situation and be guided by clinical signs of bleeding tendency, factor
activity levels and the wishes of the patient after fully informed discussion. In particular, the well known
hazard of failed airway after general anaesthesia in the pregnant patient should be
considered. It is likely that many spinal/epidurals have been performed on women with
undiagnosed VWD without sequelae.
The factor activity levels should be near normal prior to spinal epidural injection. The
Association of Hemophilia Clinic Directors of Canada Clinical Practice Guidelines suggest
that a factor level of 40 – 50% is desirable for prophylaxis for severe physical trauma
without bleeding. If a bloody tap occurs it may be appropriate to raise levels to 80 – 100%
level. Some centres recommend that this higher level is desirable before lumbar puncture or
epidural injection.
Increase in factor activity levels may be achieved by:
DDAVP 0.3 µg/kg IV over 20 min
Factor VIII (also contains VWF) 10 – 40 U/kg
Tranexamic Acid 10 mg/kg IV
Tachyyphylaxis can occur with repeated doses of DDAVP; prophylaxis before
spinal/epidural may make treatment for a later PPH less effective.
The risk of vascular trauma from spinal/epidural infection may be reduced by:
Action Rationale
Administration by experienced practitioner - To minimise unsuccessful attempts
Spinal injection rather than epidural catheter insertion -To avoid catheter trauma to epidural veins.
Lateral postion during injection - Reduces epidural vein pressure, making them less susceptible to puncture
10 ml of solution through needle before passing epidural catheter - Reduces rate of intravascular catheterisation
Prompt removal of epidural catheter after delivery - To remove before fall in coagulation
factor levels
The risk of permanent neurologic damage from an epidural haematoma will be minimised by
prompt recognition and treatment.
Stategies to reduce the harm of epidural haematoma
Using analgesic regimens that do not cause motor block, or at least do not cause it for long
Frequent observation for unexpected motor block, back pain, sacral anaesthesia or urinary
retention.
Factor VIII administration to achieve 100% levels
Prompt MRI and neurosurgical referral and preparation for emergency lumbar laminectomy.
Analgesia when regional analgesia is contraindicated, or prior to the return
of coagulation tests
In the event that a parturient requests prompt analgesia for extremely painful labour and the clinical history or signs are not reassuring of near-normal clotting, parenteral opioid may provide some relief. Campbell suggests that 300 µg/h of fentanyl is usually required to achieve 3–4/10 pain scores in labour.
Suggested regimen for Fentanyl Patient-controlled intravenous analgesia
1.Resus equipment
2. SpO2
3. one to one nursing
4. Patient education
5."patient only!" to be clearly indicated to support persons
6. 2-3 µg/kg IV loading
7. PCIA 50 µg bolus, 10 min lockout
8. Decrease lockout to 5 min
9. Increase bolus to 75µg
10. rarely, increase to 100µg bolus
DC Campbell: Parenteral Opioids for Labor Analgesia Clinical Obstetrics&Gynecology 46, 3, 616-622
In conclusion, the administration of regional analgesia/anaesthesia to a parturient with
bleeding disorder should be individualised and done according to the clinical situation, the available haematological information and treatment and the fully informed wishes of the parturient. The use of regional analgesia/anaesthesia is only one aspect of the care of these women; postpartum haemorrhage may also occur and may require treatment by DDAVP, factor VIII, tranexamic acid and other blood products including cryoprecipitate and fresh frozen plasma.
Most of the epidemiological human data is reassuring, but some authors are concerned about subtle neuronal effects which might effect intellect and behaviour in the fetus’ later life. According to this table, a standard modern general anaesthetic will use drugs of B and C category.
The Australian Therapeutic Goods Administration has categorised the following drugs:
Category A
Drugs which have been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed.
Halothane, ketamine, nitrous oxide, codeine, dexamethasone, bupivacaine, lignocaine, suxamethonium, thiopentone, paracetamol
Category B1
Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals [ NB ] have not shown evidence of an increased occurrence of fetal damage.
Dolasetron, ropivacaine
Category B2
Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals [ NB ] are inadequate or may be lacking, but available data show no evidence of an increased occurrence of fetal damage.
Sevoflurane, rocuronium, neostigmine
Category B3
Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals [ NB ] have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.
Clonidine, isoflurane
Category C
Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details.
Alfentanil, diclofenac, droperidol, fentanyl, midazolam, morphine, oxycodone, tramadol, unfractionated heparin, propofol, vecuronium
Category D
Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects. Accompanying texts should be consulted for further details.
Warfarin
Category X
Drugs which have such a high risk of causing permanent damage to the fetus that they should not be used in pregnancy or when there is a possibility of pregnancy.
None which are relevant to usual anaesthesia. Thalidomide.
NSAIDs should be avoided in later pregnancy as they can cause cause premature closure of the ductus arteriosis and renal impairment in the neonate.
Attention should be paid to uterine perfusion pressure and oxygenation. Caval compression should be minimised. Gastric emptying can be impaired from the 13th week of pregnancy. RA is usually preferred if appropriate.