Phenylephrine is currently recommended as the consensus choice for managing hypotension during spinal anaesthesia for Caesarean section. Ephedrine should only be used when mild hypotension is associated with bradycardia.

  Daniel Jolley

Recommendations from the guidelines:

1. Hypotension following spinal or combined spinal-epidural anaesthesia at caesarean section causes both maternal and fetal/neonatal adverse effects.
2. Hypotension is frequent – vasopressors should be used routinely and preferably prophylactically.
3. α‐agonist drugs are the most appropriate agents to treat or prevent hypotension following spinal anaesthesia. Although those with a small amount of β‐agonist activity may have the best profile (noradrenaline (norepinephrine), metaraminol), phenylephrine is currently recommended due to the amount of supporting data. Single‐dilution techniques, and/or prefilled syringes should be considered.
4. Left lateral uterine displacement and intravenous (i.v.) colloid pre‐loading or crystalloid coloading, should be used in addition to vasopressors.
5. The aim should be to maintain systolic arterial pressure (SAP) at ≥ 90% of an accurate baseline obtained before spinal anaesthesia, and avoid a decrease to < 80% baseline. We recommend a variable rate prophylactic infusion of phenylephrine using a syringe pump. This should be started at 25–50 μg.min−1 immediately after the intrathecal local anaesthetic injection, and titrated to blood pressure and pulse rate. Top‐up boluses may be required.
6. Maternal heart rate can be used as a surrogate for cardiac output if the latter is not being monitored; both tachycardia and bradycardia should be avoided.
7. When using an α‐agonist as the first‐line vasopressor, small doses of ephedrine are suitable to manage SAP < 90% of baseline combined with a low heart rate. For bradycardia with hypotension, an anticholinergic drug (glycopyrronium (glycopyrrolate) or atropine) may be required. Adrenaline (epinephrine) should be used for circulatory collapse.
8. The use of smart pumps and double (two drug) vasopressor infusions can lead to greater cardiovascular stability than that achieved with physician‐controlled infusions.
9. Women with pre‐eclampsia develop less hypotension after spinal anaesthesia than healthy women. Abrupt decreases in blood pressure are undesirable because of the potential for decreased uteroplacental blood flow. A prophylactic vasopressor infusion may not be required but, if used, should be started at a lower rate than for healthy women.
10. Women with cardiac disease should be assessed on an individual basis; some conditions are best managed with phenylephrine (an arterial constrictor without positive inotropic effect), whereas others respond best to ephedrine (producing positive inotropic and chronotropic effect).

  Daniel Jolley