[CG] Surgery during pregnancy - incidental

• It is estimated that 0.2% of parturients will require a surgical procedure whilst pregnant¹
• Indications for surgery may be pregnancy or non-pregnancy related
• To maintain maternal safety the physiological and anatomical changes of pregnancy must be considered and surgical and anaesthetic techniques modified accordingly
• Fetal wellbeing is related to the avoidance of fetal asphyxia, teratogenic drugs and preterm labour. Maternal hypoxia, extreme hypo or hypercarbia, hypotension and uterine hypertonus must be avoided.
• A review examining 54 studies (12,452 patients) concluded;

“The risk of maternal death appears to be very low; surgery and anaesthesia do not appear to be major risk factors for spontaneous abortion.  Non-obstetric surgery does not increase the risk of major birth defects. Acute appendicitis (especially when accompanied by peritonitis) appears to be a genuine risk for surgery induced labour or fetal loss”²

• Surgery should be performed in the second trimester where possible. Elective surgery is generally postponed until at least 6 weeks after delivery.  However, a pregnant woman should never be denied indicated surgery, regardless of trimester³
• Pregnancy is not a contraindication for laparoscopic surgery. Discussion with an obstetrician is advised and consideration should be given to fetal monitoring.  Intra-abdominal pressures should be kept below 12mmHg.
• Anti-D should be considered in patients who are rhesus negative as surgery is a potentially sensitizing event (PSE). This should be discussed with the obstetrician:
  • < 12 weeks gestation – anti D not required
  • o 12 – 20 weeks – 25OU IM anti-D into deltoid within 72 hours of PSE.
  • >20 weeks – Kleihauer test, 500U IM anti-D within 72 hours of PSE. Further doses as directed by Kleihauer result (discuss with obstetrician/haematologist).
• An abdominal shield should be employed wherever possible if radiation exposure is expected during surgery.

Pre-operative

• Ensure FBC and G+S sent (other bloods dependent on clinical situation). Note Rhesus status
  and if rhesus –ve, consider anti-D as directed above
• Discuss case with ‘Senior on’ anaesthetic consultant. Obstetric anaesthetic consultant should be informed in all cases over 20 weeks gestation and in any other case where advice is required
• Give Ranitidine 150mg po or 50mg IV pre-operatively
• Give Sodium Citrate 0.3M oral solution prior to induction in patients > 16 weeks gestation (can be obtained from labour ward)
• Ensure availability of Syntocinon, Ergometrine, Syntometrine and Hemabate^®
• Site 14 / 16G cannula(e)

Intra-operative

• 15° left lateral tilt mandatory after 16 weeks and consider at earlier gestation if hypotensive, symptomatic, or large bump (e.g. multiples)
• Regional technique preferable where feasible. N.B. Uteroplacental circulation is not auto-regulated and perfusion is entirely dependent on maintenance of adequate maternal blood pressure and cardiac output. Placental perfusion must be maintained by rapid treatment of any hypotension
• Smaller volumes of local anaesthetic required for spinal / epidural blockade. Spinal dose of 2.5ml 0.5% heavy bupivacaine + 0.3mg diamorphine used to achieve block to T4 for caesarean section at term. Greater than 2.5ml used in preterm, IUGR etc. Advice can be obtained from consultant obstetric anaesthetist
• If GA, careful pre-oxygenation - consider head up position, ramping, Oxford pillow, nasal prongs
• RSI after 16 weeks or if symptomatic of reflux
• Use stubby handle and have video-laryngoscope available
• Use small ETT (size 7). Have bougie / stylet available
• Thiopentone and Suxamethonium are standard for RSI in obstetric patients (though other induction agents and neuromuscular blockers may be used depending on individual preference)
• Consider short acting opioid to obtund response to intubation in presence of hypertension / preeclampsia. If these conditions are present, consultant obstetric anaesthetist should attend wherever possible
• Use of drugs with established safety profile - Thiopentone, Suxamethonium, opioids, neuromuscular blockers, Ondansetron, volatile agents, local anaesthetics
• MHRA suggests Nitrous Oxide best avoided in first trimester (though not absolutely contraindicated if benefits thought to outweigh risk)”
• Avoid NSAIDs and Ketamine before delivery
• ETCO₂ should be kept in the normal pregnant range (3.7-4.2kPa)
• Consider arterial line and PaCO₂ monitoring in laparoscopic patients as PaCO₂ may be significantly greater than ETCO₂
• Maintain SBP within 20% of pre-operative levels (placental flow dependent on maternal BP / CO)
• Phenylephrine is commonly used to treat hypotension. Make up as Phenylephrine 10mg in 500ml (20 micrograms/ml).  Give either as Phenylephrine infusion (50ml syringe in PK pump at 60100ml/hr) or as Phenylephrine 40-60 microgram boluses
• Reversal with Neostigmine and Atropine (Neostigmine crosses the placenta and can cause fetal bradycardia. Glycopyrrolate does not cross the placenta)
• Consider intra-operative use of intermittent compression stockings in view of increased risk of thromboembolism
• Analgesia - Paracetamol (weight appropriate dose), opioids and regional techniques can be used. NSAIDs can be used following delivery of the fetus if no other contraindications 

Post-operative

• Post-op fetal monitoring as directed by obstetrician
• Discharge destination dependent on gestation and clinical situation – liaise with surgeon / obstetrician
• Thromboprophylaxis - Early mobilisation, hydration, TEDs, LMWH (unless contraindicated). Follow GGC antenatal / postnatal guidance as appropriate. This can be obtained via the Maternity Hospital Coordinator or via Staffnet
• If breast-feeding, medications should be administered immediately after a breastfeed where possible. Consult Clinical Pharmacist, Medicines Information Service or British National Formulary for further guidance

Contact numbers (GRI / PRM)

• Labour Ward – tel 25216
• PRM Hospital coordinator - 13707
• Obstetric StR - Page 10055
• Obstetric consultant – Page 10056, 8:30-22:00 (via switchboard outwith these hours)
• Anaesthetics StR (duty 2) – Page 13298 / 13299
• Anaesthetic consultant – Page 13259 (via switchboard after 18:00)
• Consultant obstetric anaesthetist / twilight anaesthetist – Page 12205 (08:00-
  00:00), via switchboard after 00:00
• Neonatal StR - page 12200
• Neonatal consultant – page 12210

Contact numbers (RAH)

• Labour ward – Tel. 06743
• Maternity Hospital Coordinator – Available via labour ward on page 56297
• Obstetric StR - Page 56014
• Obstetric consultant – Page 56193, 9:00-17:00 (via switchboard outwith these hours)
• Anaesthetic StR  – Page 56233
• Anaesthetic consultant – Via Labour ward or switchboard
• Neonatal StR - Page 56017
• Neonatal consultant – Via switchboard

Contact Numbers (QEUH)

• Maternity Hospital Coordinator – Page 17292
• Obstetric StR – Page 17111
• Obstetric Consultant – Page 17222
• Anaesthetic StR – (duty 2) – Page 17307
• Anaesthetist consultant – Consultant obstetric anaesthetist –Page 17272
• Neonatal consultant – Tel: 62261