Anaes Vivas · Anaesthetic adjuncts
Data viva — ephedrine among the perioperative vasopressors
A data viva on ephedrine placed against phenylephrine, metaraminol and noradrenaline. The discriminating data points: ephedrine is mixed-acting with dominant indirect noradrenaline release (taught), raises heart rate, crosses the placenta (lower umbilical-artery pH than phenylephrine, WMD +0.03 — Lee 2002) and the blood-brain barrier, lasts about 60 to 90 minutes (taught), and exhibits tachyphylaxis. Phenylephrine is the pure alpha-1 agent preferred in obstetrics on the pH evidence (Lee 2002). The vasopressor-and-delirium evidence (Dong 2026, null for ephedrine versus norepinephrine) bounds the selection logic.
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A table summarises four perioperative vasopressors against five properties:
| Agent | Dominant receptor profile | Heart-rate effect | Placental transfer | Duration after IV bolus | Tachyphylaxis |
|---|---|---|---|---|---|
| Ephedrine | Mixed: weak direct alpha-1, beta-1, beta-2 PLUS dominant indirect noradrenaline release (taught) | Raises (beta-1) | Yes (lower UA pH than phenyl, WMD +0.03, Lee 2002) | about 60 to 90 minutes (taught) | Yes (store depletion, taught) |
| Phenylephrine | Pure direct alpha-1 | Lowers (reflex bradycardia) | First-line in obstetrics on pH grounds (Lee 2002) | about 5 to 10 minutes (taught) | No |
| Metaraminol | Mixed: stronger direct alpha-1 plus indirect (taught) | Slight rise or minimal | Alternative in obstetrics (taught) | about 20 to 30 minutes (taught) | Mild (taught) |
| Noradrenaline | Direct alpha-1 plus beta-1 (taught) | Slight rise | Infusion agent for shock (taught) | Infusion only | No |
Interpret the table and justify the clinical selection of vasopressor for each of the following scenarios: obstetric spinal hypotension, perioperative hypotension with bradycardia, generic anaesthesia-induced vasoplegia in an older adult at risk of delirium, and refractory vasoplegic shock (taught table — the cross-reactivity study [1] and the delirium database analysis [4] own no table row; the obstetric cells are Lee-exact [6]).[1][4][6]
References5ShowHide
- [1]Sainz-Pastor N, et al. Challenges in the interpretation of amphetamine results: differences of reactivity with ephedrine. Scand J Clin Lab Invest, 2026.PMID 42364133
- [2]Mohammed M, et al. A case report of acute right ventricular failure. Eur Heart J Case Rep, 2026.PMID 42339184
- [3]Parkinson EA, et al. The Financial and Environmental Cost of Anaesthetic Emergency Drugs: Comparing Ampoules With Prefilled Syringes. Cureus, 2026.PMID 42005180
- [4]Dong T, et al. Vasopressor Selection and Postoperative Delirium in Older Adults. Semin Cardiothorac Vasc Anesth, 2026.PMID 42359892
- [6]Lee A, et al. A quantitative, systematic review of randomized controlled trials of ephedrine versus phenylephrine for the management of hypotension during spinal anesthesia for cesarean delivery. Anesth Analg, 2002.PMID 11916798