Anaesthesia for Obstetric Surgical Procedures September 2010

Retained placenta Sensory block to T10 required Spinal/existing epidural Patient potentially hypovolaemic

Repair of perineal tear Spinal/existing epidural Good quality saddle block required Potentially hypovolaemic patient

Anaesthesia for Cervical Suture 1st/2nd trimester Spinal/GA If GA Avoid prolonged exposure to nitrous oxide Potentially teratogenic in first trimester Avoid hypotension/hypercarbia – fetal acidosis

Introduction NHS maternity statistics 2008-09: UK c/section rate = 24.6% RJMH c/section rate = 36.2% NOAD 2007: anaesthesia for c/section Spinal – 59.6% Epidural top-up – 22.1% GA – 10.1% CSE – 7.2% De novo epidural – 0.8%

RCOA Audit Standards Elective c/section > 95% RA Emergency c/section> 85% RA Elective c/section <1% RA to GA Emergency c/section < 3% RA to GA

Elective c/section Common indications: Maternal request! Breech presentation Previous c/section Placenta praevia Significant medical conditions

Choice of Anaesthetic Patients preference Patients physical profile, health considerations, pregnancy factors Anticipated surgical difficulties Experience and speed of surgeon

Preparation for Anaesthesia Preop assessment Informed consent Antacid prophylaxis Fully prepared anaesthetic room/theatre Checked anaesthetic machine Monitoring equipment Tilting operating table Resuscitation equipment Trained anaesthetic assistant Large bore I.V. access

Spinal Anaesthesia Used >90% elective LSCS Incidence of PDPH approx 1:400 due to small gauge PP needles Technically simple Consistent, dense quality of block Failure rate approx 1%

Spinal Anaesthesia Standard technique PP needle, no larger than 25G to minimise PDPH risk Injection at, or below L3/L4 interspace to avoid damage to conus Diamorphine 300mcg Injection performed in sitting position, then moved immediately to L tilted supine position on completion Phenylephrine ivi to prevent hypotension

Spinal Anaesthesia Hyperbaric Bupivicaine 0.5% - most used LA in UK Recommended doses vary Surgery requires sensory blockade to T4 Patient factors influencing dose Height Abdominal size

Intrathecal Opiates Fentanyl Morphine Diamorphine Side Effects: Highly lipid soluble Reduced intraop discomfort Provides no post op analgesia Morphine Long duration of action Little intraop effect due to poor lipophillicity Diamorphine Rapid onset Side Effects: PONV approx 30% Pruritus

Spinal induced hypotension Can cause fetal distress Symptoms: dizziness, N&V Should be treated aggressively Approp positioning Fluid preloading Use of Phenylephrine ivi Titrated to maternal BP Higher fetal pH than Ephedrine

Spinal after epidural Technique most likely to lead to high/total spinal anaesthesia. ? Dural sac compression by epidural fluid No formula for reducing spinal dose. NB inadequate block Precautions Warn patient of risk of conversion to GA Assess airway Perform spinal in approp environment Reduction of spinal dose Consider leaving epidural catheter in situ

Epidural ‘top-up’ Category 2 LSCS with epidural in situ Slow onset anaesthesia Inferior anaesthesia to spinal during surgery L-Bupivicaine 0.5%; Ropivicaine 0.75%; supplemental Diamorphine.

CSE 3 approaches ‘Needle through needle’ ‘Full’ dose spinal with epidural back up if inadequate block height/duration Reduced dose spinal with supplemental epidural top-ups Epidural volume extension-low dose spinal extended by dural sac compression using epidural saline ‘Needle through needle’ Separate needle, separate interspace

CSE Used to reduce incidence of spinal failure Tall patients IUGR Prolonged surgery Reduces haemodynamic changes by more gradual onset anaesthesia; reduced risk of excessive block height Cardiac patients Short patients Short duration of blockade esp motor blockade

Continuous Spinal Niche role ‘Difficult’ equipment PDPH Careful titration of dose Haemodynamic stability Cardiac disease Extremely small stature Severe skeletal deformity Extended period of anaesthesia

Pain during LSCS Leading cause of litigation Informed consent Closed claims analysis 1995-2007 Pain during surgery - 31% (57) Informed consent Give adequate doses of drugs including opioid Produce and document adequate sensory and motor block Management Alfentanil 250mcg iv Entonox Conversion to GA NB. Clear documentation of management esp if patient refuses GA

GA Indications Refusal of RA Contraindications eg. Coagulopathy Insufficient time to establish RA Serious haemorrhage anticipated Failed RA

GA Reliable and safe if Aspiration prophylaxis Trained anaesthetic assistance Meticulous pre-oxygenation Well rehearsed failed intubation drill Approp drug regimen to reduce incidence of awareness Awake extubation

Drugs used for GA RSI with cricoid pressure Thiopentone/Propofol? Poorer neonatal profile Shorter duration of amnesia Longer time to recovery of spontaneous ventilation Suxamethonium/Rocuronium? Inadequate doses assoc with difficult intubations NB 1.5mg/kg; Increased Vd Prolonged action of Rocuronium NB. Sugammadex

Perioperative Drugs Opiates at induction and post op analgesia On delivery of neonate Syntocinon 5IU and IVI Prophylactic antibiotics Thromboprophylaxis

Complications Failed intubation (1 in 300) Aspiration (1 in 400-600) Increased fatty tissue Complete dentition Increased pharnygeal and laryngeal oedema Incorrect drug dosages Large tongue Large breasts Increasing obesity Aspiration (1 in 400-600) Awareness Increased intaop blood loss PONV

Post op pain relief Introp: Post op: Diclofenac 100mg PR Intrathecal Diamorphine IV Morphine and TAP blocks Post op: Diclofenac 50mg PO TID Paracetamol 1g PO QID Codeine 30-60mg PO QID

Emergency LSCS Grades of urgency – category 1 to 4 Nationally accepted classification ‘Continuum of risk’ Facilitates audit Improves multidisciplinary communication Individual, ‘case by case’ approach to decision to delivery interval

Emergency LSCS Category 1 & 2 In utero fetal resuscitation Syntocinon off Position full L lateral Oxygen I.V fluids Low BP – vasopressors Tocolysis: GTN 400mcg/B2 agonist Choice of anaesthesia Post op analgesia Post op care