1. Anaesthetic Management Of Cardiac Patients
Dr Jeremy Corfe
Consultant Anaesthetist
Norfolk and Norwich University Hospital

2. CVS Physiology

3. CVS Physiology in Pregnancy
Roos-Hesselink JW, Duvekot JJ, Thorne SA. Pregnancy in high risk cardiac conditions. Heart 2009; 95: 680-6
Plasma volume reaches a maximum of 40% above baseline at 24 weeks gestation. A 30–50% increase in CO occurs in normal pregnancy. In early pregnancy increased CO is primarily related to the rise in stroke volume; however, in late pregnancy, heart rate is the major factor. Heart rate starts to rise at 20 weeks and increases until 32 weeks.
The increased intravascular blood volume partly explains the higher dosages of drugs required to achieve therapeutic plasma concentrations plus the raised renal perfusion and the higher hepatic metabolism. Giving increased drug clearance.

4. Cardiac Output in Labour
CO increase:
Latent phase: 15%
1st Stage: 25%
2nd Stage: 50%
3rd Stage: 80%
CO = SV x HR

5. 1st Stage Cardiac Output
⇧ HR - sympathetic
⇧ SV - autotransfusion
~ 500ml per contraction
⇧ BP with contractions
Systolic %
Diastolic %
Epidurals help

6. 2nd Stage Cardiac Output
⇧ Circulating Oxytocin (Ferguson’s reflex)
⇧ strength contractions = ⇧ autotransfusion
⇧ HR
Active pushing – Valsalva

7. 3rd Stage Cardiac Output
3rd Stage increase in CO
Autotransfusion from contracted Uterus ≤ 1500ml
Aortocaval compression removed
Offset by normal blood loss at delivery
Furosemide is useful

8. Pharmacology in labour

9. Tocolytics
β2 agonists – Terbutaline, Salbutamol, Ritodrine
⇧ HR

10. Tocolytics β2 agonists – Terbutaline, Salbutamol, Ritodrine Nifedipine
⇩ SVR + ⇩ BP with reflex ⇧ HR + ⇧ Contractility
≤40mg in 1 hour, followed by 20mg SR TDS
Normal antihypertensive dose 20mg / day

11. Tocolytics β2 agonists – Terbutaline, Salbutamol, Ritodrine Nifedipine
Atosiban
Oxytocin receptor antagonist
Animal studies = no effects on HR, contractility or BP
Drug of choice in cardiac patients?
Availability?
£52 per vial.

12. Uterotonics Oxytocin Used for Augmentation of labour
1st line prophylaxis & treatment of uterine atony
Immediate onset, short duration – 5 minutes
Weak ADH effect

13. Uterotonics Why? Oxytocin Case reports of Chest pain
Ischaemic ECG changes
Cardiac arrest
Why?

14. Uterotonics Oxytocin CVS effects ⇩ SVR ⇧ HR + ⇧ SV = ⇧ CO
Langesæter E et al. Br. J. Anaesth. 2009;103:

15. Uterotonics Oxytocin CVS effects ⇩ SVR ⇧ HR + ⇧ SV = ⇧ CO
Effects worse with
IV bolus
10U vs 5U
Thomas J S et al. Br. J. Anaesth. 2007;98:

16. Uterotonics Oxytocin strategies in high risk patients GIVE SLOWLY
5U “bolus” via pump over 10 – 15 minutes
Or avoid bolus & titrate infusion to effect
Use concentrated solutions for postpartum regime

17. Uterotonics Ergometrine
Direct effect on smooth muscle - ⇧ uterine tone
Half life 30 – 120 minutes
Effects last approximately 3 hours
Works well
But.....
Lots of case reports of MI and death, severe hypertension, pulmonary oedema

18. Uterotonics Ergometrine Also acts on α1, D2 & 5HT2 receptors
Vasoconstriction – systemic & pulmonary hypertension
Coronary artery spasm
Bronchospasm
Vomiting
Lots of case reports of MI and death, severe hypertension, pulmonary oedema

19. Uterotonics Ergometrine Contraindicated in Pre-eclampsia
Coronary artery disease
Aortopathies
Aneurysms
Lots of case reports of MI and death, severe hypertension, pulmonary oedema

20. Uterotonics Prostaglandins PGE1 & PGE2 – Misoprostol & Dinoprostone
PGF2α – Carboprost
Diarrhoea, vomiting, pyrexia, shivering
Haemodynamic effects dependent on type
Misoprostol - vasodilatation
Carboprost - vasoconstriction

21. Uterotonics Prostaglandins - Misoprostol (PGE1) 800mcg PR
Not as effective as Oxytocin or Ergometrine
Limited haemodynamic effects
Beware of shivering
Best for cardiac patients?

22. Uterotonics Prostaglandins - Carboprost (PGF2α)
Normally the drug of choice for refractory uterine atony
BUT
Bronchospasm
⇧ Pulmonary shunt
⇧ PVR & ⇧ PAP
SVR
Contraindicated in
Asthmatics
Single ventricle
Pulmonary hypertension

23. Uterotonics: order of use in high risk patients
Oxytocin
Misoprostol
Beware of shivering
Carboprost
Do NOT give to single ventricle, ⇧PAP, shunt, asthmatics
Ergometrine
Do NOT give to pre-eclamptics, aortopathies, aneurysms coronary artery disease
Only proceed if life threatening PPH, consider physical measures first

24. Other drugs Labetolol & Hydralazine MgSO4
Dexamethasone / Betamethasone
Na+ + H2O retention

25. Common Anaesthetic agents
Induction agents – Propofol / Thiopentone
Negative inotropes
⇩ SVR
Maintenance – Isoflurane, Sevoflurane, Desflurane
Mild negative inotropes
Dose dependent tocolytic effect

26. Other commonly used Anaesthetic drugs
Vasopressors
Phenylephrine
Potent α1 agonist
Maternal bradycardia
Anticholinergics
Glycopyrolate / Atropine
Ephedrine
Direct β1 + indirect α1
Fetal effects

27. Analgesia & Anaesthesia

28. Analgesia & Anaesthesia
1st stage: T9-L1
2nd stage: S2-S4
Operative delivery
Rectus muscles & parietal peritoneum
innervated up to T6
Block above T4 may block cardiac
accelerator fibres

29. Epidural Analgesia Advantages Great analgesia
Abolishes sympathetic response to labour
Can be topped up for operative anaesthesia

30. Epidural Analgesia Disadvantages
Sympathetic block - vasodilatation and ⇩ SVR
Normally well tolerated
Avoid with low dose incremental dosing /- filling & vasopressors
Beware fixed output states and R>L shunts
Increased risk instrumental delivery
Timing of anticoagulants
Decreased SVR – good for AR

31. Remifentanil PCA for labour analgesia
Ultra short acting potent intravenous opioid
Rapidly metabolised by mother and baby
Does not accumulate
Can be used when epidural contraindicated
But
Analgesia inferior to epidurals
Will not completely block sympathetic effects of labour

32. Operative Delivery – Regional Anaesthesia
Preferred to general anaesthesia
Avoids management of more difficult obstetric airway
Greater patient satisfaction
Effects as epidural analgesia - vasodilatation and ⇩ SVR
More profound & quicker onset (Spinal > CSE > Epidural)
Use
Arterial line before insertion
Low dose CSE technique / slow epidural top up

33. General Anaesthesia Advantages Quick Useful in very anxious patients
Allows certain therapeutic interventions
DC cardioversion, 100% O2, post op ventilation
Only option if anticoagulated

34. General Anaesthesia Disadvantages Difficult obstetric airway
Hypotension – induction / maintenance
Hypertension & tachycardia – intubation / extubation
Connell et al. Can J Anaesth 1980; 27:

35. General Anaesthesia Disadvantages Difficult obstetric airway
Hypotension – induction / maintenance
Hypertension & tachycardia – intubation / extubation
Arterial line
Cardiostable anaesthetic – lots of opiates
Reduced patient satisfaction
Inferior analgesia, PONV

36. Summary

37. Summary

38. Summary

39. Summary Order of use of Uterotonics in high risk patients: Oxytocin
Misoprostol
Carboprost
Ergometrine
Only proceed if life threatening PPH, consider physical measures first

40. Summary Anaesthetic agents and techniques Regional is preferred
All cause ⇩ SVR
Spinal > GA > epidural
Arterial line and low dose CSE works well
Consider anticoagulant timing