Anaes Vivas · Anaesthetic adjuncts
Data viva — adrenaline among the catecholamines and vasopressors
A data viva placing adrenaline against noradrenaline, phenylephrine and ephedrine. The discriminating data points: adrenaline is the only agent with significant beta-2 activity and the only direct-acting agent with full dose-dependent selectivity (low beta-2 to high alpha-1 — taught tiers); it is the first-line anaphylaxis drug (IM 500 micrograms, taught standard; community early-access context Najem 2026); arrest dosing is the taught ALS standard with early timing evidence-backed (Ahn 2026); it is the most arrhythmogenic catecholamine (taught ranking); and it has a very short half-life of about 2 to 3 minutes (taught pharmacology) requiring continuous infusion. Noradrenaline is the sustained-shock agent with no beta-2 and less arrhythmia; phenylephrine is the pure alpha-1, tachycardia-averse pressor; ephedrine is the mixed-acting, heart-rate-raising outlier. The lactate rise is beta-2 glycolysis and not lactic acidosis; extravasation is treated with phentolamine (cohort-exact 31 of 3734, 0.8%, Shyu 2025). No audit trigger-ranking is carried. Delirium null in older adults (OR 0.97, P 0.9065, Dong 2026) frames the selection logic.
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A table summarises four agents used in perioperative vasopressor and catecholamine therapy against six properties:
[2]| Agent | Dominant receptor profile | Beta-2 activity | Dose-dependent selectivity | Anaphylaxis role | Arrhythmogenic liability | Half-life | | --- | --- | --- | --- | --- | --- | --- | | Adrenaline | Direct alpha-1, alpha-2, beta-1, beta-2 | Significant | Yes (low beta-2, moderate beta-1 plus beta-2, high alpha-1) | First-line, IM 500 micrograms | Highest | about 2 to 3 minutes | | Noradrenaline | Direct alpha-1, beta-1; negligible beta-2 | Negligible | Minimal | Not first-line | Lower than adrenaline | minutes (infusion) | | Phenylephrine | Pure direct alpha-1 | None | None (pure alpha-1) | Not used (no beta-2) | Low (reflex bradycardia) | about 5 to 10 minutes | | Ephedrine | Mixed: weak direct alpha-1, beta-1, beta-2 plus dominant indirect noradrenaline release | Weak | No | Not first-line | Moderate (tachycardia) | about 60 to 90 minutes |
Interpret the table and justify the clinical selection for each of the following scenarios: acute perioperative anaphylaxis after rocuronium, sustained vasoplegic septic shock, a combined inotrope-and-pressor for cardiogenic shock, and routine anaesthesia-induced hypotension in an older adult at risk of delirium.[1][4]
References8ShowHide
- [1]Najem J, et al. Effectiveness of a Provincial Law to Improve Epinephrine Use for Anaphylaxis in Schools. Int Arch Allergy Immunol, 2026.PMID 42360928
- [2]Yahya R, et al. First-line vasopressor therapy in neonates with fluid-refractory septic shock. Am J Emerg Med, 2026.PMID 42361705
- [3]Chirumamilla L, et al. Multidisciplinary management of refractory malignant upper GI bleeding. BMJ Case Rep, 2026.PMID 42362336
- [4]Dong T, et al. Vasopressor Selection and Postoperative Delirium in Older Adults. Semin Cardiothorac Vasc Anesth, 2026.PMID 42359892
- [5]Shyu D, et al. Overview of Peripheral Vasopressor Use in an Academic Health System. Ann Am Thorac Soc, 2025.PMID 40126143
- [6]Ahn C, et al. Association Between Epinephrine Administration Timing and Outcomes in Adult Out-of-Hospital Cardiac Arrest: A Systematic Review and Dose-Response Meta-Analysis. Medicina (Kaunas), 2026.PMID 42654392
- [7]Khalil B, Rosani A, et al. Physiology, Catecholamines. StatPearls, 2026.PMID 29939538
- [8]Dodd A, Turner PJ, Whyte A, et al. Evidence update for the treatment of anaphylaxis. Resuscitation, 2021.PMID 33895231