Regional Anaesthesia for Caesarean Section Warwick D. Ngan Kee

Transcription

1 Regional Anaesthesia for Caesarean Section Warwick D. Ngan Kee Chair, Department of Anesthesiology Sidra Medicine Doha, Qatar

2 D I S C L O S U R E S No financial disclosures No industry affiliations No conflicts of interest

3 OBJECTIVES 1. Provide an overview of contemporary practice of spinal anaesthesia for caesarean section. 2. Discuss selected controversial areas.

4 OUTLINE: Intrathecal drug choice IV fluid management Lateral tilt Use of Vasopressors

5 OUTLINE: Intrathecal drug choice

6 Local Anaesthetic Is Bupivacaine the local anaesthetic of choice? Bupivacaine

7 Levobupivacaine Dextrobupivacaine

8 LEVOISOMERS Levobupivacaine Ropivacaine Lower toxicity Less motor block

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10 Malhotra et al. Int J Obstet Anesth 2016;27:9-16

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13 Hyperbaric vs Plain: 2013 Faster onset Less conversion to GA 2016 Faster onset GA & supplementation similar 2018 Faster onset GA & supplementation similar

14 Less variability of block Postural manipulation Greater hypotension

15 What Dose of Bupivacaine?

16 What Dose of Bupivacaine? Heavy Bupivacaine 0.5% (ml) ( ) Weight (kg) Height (cm) Parity 1/2 Gestation (wk)/ Acknowledgement: D. Fogarty

17 Local Anaesthetic + Additives Bupivacaine

18 Opioids Adrenaline Clonidine Neostigmine Ketamine

19 Adding adjunct agents Possible advantages: 1. Decrease side effects 2. Increase efficacy

20 Adding adjunct agents Possible disadvantages: 1. Drug error 2. Breach of sterility 3. Incompatibility 4. Cost 5. Safety (often off-label )

21 Opioids Adrenaline Clonidine Neostigmine Ketamine Only add an opioid

22 Local Anaesthetic + Lipophilic Opioid Bupivacaine Fentanyl

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24 Elective Caesareans (n=56) Spinal Anaesthesia Bupivacaine: weight based dose Added Fentanyl (7 doses) 0 µg 2.5 µg 5 µg 6.25 µg 12.5 µg 25 µg 37.5 µg 50 µg Hunt et al. Anesthesiology 1989;71:

25 Intraoperative Opioid Supplementation 100 Intraop Opioid (%) % 50% 40 25% % 0% 0% 0% 0% Fentanyl Dose (µg) Hunt et al. Anesthesiology 1989;71:

26 Nausea and Vomiting?

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28 Manullang et al. Anesth Analg 2000;90: Elective Spinal Caesareans (n=30) Hyperbaric Bupivacaine 12 mg IV Ondansetron 4 mg IT Fentanyl 15 µg FENTANYL: Less intraoperative pain FENTANYL: Less intraoperative nausea Adding an opioid reduces visceral stimulation

29 Morphine µg Preservative-free Postop analgesia

30 Fentanyl µg + Morphine µg ALTERNATIVES Diamorphine Hydromorphone

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32 Local Anaesthetic + Additives Bupivacaine

33 Urgent Cases: No touch technique Limit attempts Simultaneous preparation for GA Local anaesthetic only

34 Arrival OT Position Spinal Injection Block Assessed Incision Delivery Kinsella et al. Anaesthesia 2010;65:664-9

35 OUTLINE: Intrathecal drug choice IV fluid management

36 Intravenous fluids Many Uncertainties

37 IV Fluid: Type and Timing Prehydration Cohydration Crystalloid Colloid

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39 Banerjee et al. Can J Anaesth 2009

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41 Ngan Kee et al. Anesthesiology 2005;103: Elective CS No Prehydration Spinal Anaesthesia Titrated Phenylephrine Infusion Rapid Crystalloid Co-hydration or Maintenance IV Fluid

42 Ngan Kee et al. Anesthesiology 2005;103:

43 Volume augmentation effect or Faster vasopressor distribution

44 Recommendation: Crystalloid: cohydration Colloid: prehydration or cohydration Don't rely on IV fluids Don't delay for IV fluids

45 OUTLINE: Intrathecal drug choice IV fluid management Lateral tilt

46 Lateral tilt

47 Lateral tilt Universally used, but: Optimal amount of tilt controversial. Usually overestimated.

48 Brit. J. Anaesth. (1972), 44, 477 TIME AND LATERAL TILT AT CAESAREAN SECTION J. S. CRAWFORD, MARILYN BURTON AND P. DAVIES SUMMARY Suggested 15 degrees

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50 Lateral Tilt Jones SJ et al. Br J Anaesth 2003: 90: 86-7.

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52 100 elective CS Spinal anaesthesia Titrated phenylephrine infusion Supine or 15 degrees left tilt Lee et al. Anesthesiology 2017;127:241-9.

53 Primary Outcome: UA Base Excess Lee et al. Anesthesiology 2017;127:241-9.

54 SECONDARY OUTCOMES: Phenylephrine dose greater with no tilt Cardiac output lower with no tilt Lee et al. Anesthesiology 2017;127:241-9.

55 Don t abandon yet? High risk cases Individual response may vary No need to ensure 15 degrees Can omit if not tolerated

56 OUTLINE: Intrathecal drug choice IV fluid management Lateral tilt Use of Vasopressors

57 Background Physiology of spinal hypotension

58 Physiology Vasodilation Aortocaval Compression Venous Return Cardiac Filling The Past Cardiac Output Hypotension

59 Physiology The Past

60 M E C H A N I C A L M E T H O D S Maintenance of cardiac filling: Lateral tilt IV fluids Leg compression

61 Physiology Vasodilation Aortocaval Compression Venous Return Cardiac Filling Mechanical Methods Of Maintaining Cardiac Filling Cardiac Output Hypotension

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63 (No prophylactic vasopressor) (No prophylactic vasopressor) Modified from: Langesaeter E et al. Anesthesiology 2008; 109:

64 Physiology Vasodilation Dependence on Sympathetic Arteriolar Vasodilation Systemic Vascular Resistance The Present Hypotension

65 Physiology Vasodilation Dependence on Sympathetic Arteriolar Vasodilation Systemic Vascular Resistance Hypotension

66 V A S O P R E S S O R S Phenylephrine

67 How best to use phenylephrine? Method of administration Timing of administration

68 Methods. Bolus vs Infusion Both effective Intermittent bolus simple Infusion convenient

69 INFUSIONS Less hypotension More hypertension Less nausea/vomiting Fewer physician interventions

70 BOLUSES: Better early BP control Lower vasopressor total dose No clinical advantage to infusions Whenever any decrease in BP

71 Timing. Prevention vs Treatment Most effective management: Start infusion immediately after intrathecal injection Give boluses as soon as BP falls

72 Alternative Vasopressors?

73 The Ideal Fast Effective Cheap CRAZY, STUPID, Titratable No bradycarda Preserve cardiac output Preserve uterine blood flow LOVE

74 The Ideal Vasopressor? Phenylephrine Alpha +++ Beta 0

75 The Ideal Vasopressor? Phenylephrine Alpha +++ Beta 0 Ideal Alternative +++ +

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77 Metaraminol Non-Inferior to Phenylephrine

78 The Ideal Vasopressor? Phenylephrine Alpha +++ Beta 0 Ideal Norepinephrine Alternative (Noradrenaline) +++ +

79 Noradrenaline/Norepinephrine Readily available, old drug. Familiar to anaesthesiologists. Easy to titrate. Preferred in ICU (better cardiac output). More available globally. Cheaper!

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81 Elective Spinal CS (n=104) Computer-controlled infusion Phenylephrine 100 mcg/ml Norepinephrine 5 mcg/ml Ngan Kee WD et al. Anesthesiology 2015;122:736-45

82 Systolic Blood Pressure Similar between groups mean (SD) P = Ngan Kee WD et al. Anesthesiology 2015;122:736-45

83 Heart Rate Greater with Norepinephrine P P = = mean mean (SD) (SD) Ngan Kee WD et al. Anesthesiology 2015;122:736-45

84 Cardiac Output Greater with Norepinephrine mean (SD) P < Ngan Kee WD et al. Anesthesiology 2015;122:736-45

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86 Prophylactic Norepinephrine Infusion Norepinephrine infusion Control Ngan Kee WD et al. Anesth Analg 2017

87 Exclusive use of Norepinephrine over 12 months Elective and emergency CS Fetal acidosis: 3-4% No ischaemic complications

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89 Onwochei et al. Anesth Analg 2017; 125:212-8 Intermittent boluses to prevent hypotension ED 90 = 5.49 µg (95% CI )

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91 Ngan Kee WD et al. Anesthesiology 2017 Elective Spinal CS (n=180) 1 st Hypotension Phenylephrine 60 to 200 µg? Norepinephrine 4 to 12 µg Restoration of BP to baseline (%)

92 Ngan Kee WD Anesthesiology 2017 Phenylephrine 100 µg = Norepinephrine 7.6 µg

93 The Ideal Fast Effective Cheap CRAZY, STUPID, LOVE Titratable No bradycarda Preserve cardiac output Preserve uterine blood flow Further work required

94 Key Points

95 Key Points 1. Heavy bupivacaine + opioid still best

96 Key Points 1. Heavy bupivacaine + opioid still best 2. IV prehydration helps (a little)

97 Key Points 1. Heavy bupivacaine + opioid still best 2. IV prehydration helps (a little) 3. Lateral tilt not mandatory (but recommended)

98 Key Points 1. Heavy bupivacaine + opioid still best 2. IV prehydration helps (a little) 3. Lateral tilt not mandatory (but recommended) 4. Use vasopressors proactively

99 Key Points 1. Heavy bupivacaine + opioid still best 2. IV prehydration helps (a little) 3. Lateral tilt not mandatory (but recommended) 4. Use vasopressors proactively 5. Consider Noradrenaline (Phenylephine 100 µg = Noradrenaline 7.6 µg)

100 Regional Anaesthesia for Caesarean Section Warwick D. Ngan Kee Chair, Department of Anesthesiology Sidra Medicine Doha, Qatar