Pregnant Patient With Cardiac Disease Flashcards
A 32-year-old lady presents to the maternity day assessment unit with decreased foetal movements at 36 weeks. She has a history of rheumatic fever.
What are the different methods available to monitor foetal wellbeing in labour?
- Fetal heart rate monitoring by Pinard, doppler, cardiotocography (CTG) or a foetal scalp electrode.
- Abdominal ultrasound scan to look at foetal growth, amniotic fluid pocket size, blood flow in the umbilical and/or uterine blood vessels and/or foetal cerebral blood vessels.
- Foetal blood sampling – foetal scalp blood can give a measure of lactate and pH.
- Less common – foetal pulse oximetry and electrocardiography.
What features on the CTG suggest an abnormal trace?
The features can be classified into reassuring, non-reassuring and abnormal, and are based around the baseline heart rate (reassuring is 110–160 bpm); baseline variability (reassuring is 5–25 bpm); and decelerations (reassuring is either none, early or variable with no concerning characteristics for less than 90 minutes).
- An abnormal trace is indicated by one of the following features:
- Heart rate below 100 or above 180 bpm.
- Acute bradycardia or a prolonged deceleration lasting for more than 3 minutes; late decelerations for over 30 minutes; or variable decelerations with concerning features in over 50% of contractions for over 30 minutes.
- Poor or increased baseline variability (<5 for 50 minutes or >25 for 25 minutes).
This patient’s CTG shows a non-reassuring trace that settles, and the obstetric team would like to carry out a category 3 caesarean section. When you take a history from her, she describes feeling more tired and short of breath during the last week. A pre-pregnancy echo shows mild aortic stenosis.
How do you proceed?
Complex - MDT
- A detailed but urgent assessment of the patient including a full history and examination, focusing on the cardiovascular system as well as anaesthetic risk and airway assessment.
- Consider an urgent ECG and echo. A clinical decision has to be made to evaluate the risk to the foetus from delay, compared to the risk to the mother from incomplete information. Whenever possible, these investigations should have occurred earlier in the pregnancy.
- This patient should ideally have been seen during pregnancy by a multidisciplinary team for a decision to be made in terms of her management during and after labour, when she is at highest risk of deterioration.
- Early escalation to consultant anaesthetist and obstetrician.
What are the anaesthetic goals in the management of this patient?
- Appropriate senior multidisciplinary care with consultant anaesthetist, obstetrician and cardiologist (and possibly cardiac surgeon).
- Consideration should be given to the site of delivery including transfer to a tertiary centre prior to delivery. Occasionally delivery is undertaken in the cardiac theatres.
- Monitoring to include invasive blood pressure monitoring.
- Consideration should be given to the effect of changes in heart rate, preload, contractility and afterload, and thus whether fluid loading or running patients with minimal fluid is appropriate. This assessment can also dictate the type of anaesthetic and the type of uterotonic that
should be used. - In this case, a general principle would be to keep heart rate low/normal, maintain contractility and afterload.
- Treat blood loss with blood products early.
- Avoidance of increases in pulmonary vascular resistance and ensure
normothermia, good oxygenation and adequate analgesia.
How would you induce anaesthesia in this patient?
GA vs RA (controlled) - NB maintenance of anaesthetic goals.
Prior to anaesthesia:
* Invasive monitoring to include AAGBI monitoring as well as arterial line and central venous access.
- Ensure left lateral tilt.
- Administer antacid prophylaxis.
- Ensure good and accessible intravenous access.
- Judicious use of fluids and vasopressor agents to maintain blood pressure.
- Give oxytocin as an infusion only and avoid ergometrine and carboprost.
- Cardiac high dependency or intensive care postoperatively.
General anaesthetic:
* Rapid sequence induction with agent of choice titrated to effect.
- Maintenance of anaesthesia using sevoflurane and nitrous oxide.
Regional anaesthetic:
* Spinal or epidural catheter with careful, slow titration of local anaesthetic and opioid to effect.
How is a combined spinal-epidural performed?
- Ensure patient consent, intravenous access, and AAGBI monitoring.
- There are two main methods of carrying out this procedure:
- “Needle through needle” – the epidural space is located using a standard Tuohy needle, then a spinal needle is passed through into the intrathecal space at the same level. After the spinal dose is injected, the spinal needle can be removed and the epidural catheter inserted and secured as normal.
- “Two space” technique – the spinal injection is performed at a level above or below the epidural catheter insertion space. Te epi- dural is usually performed before the spinal.
