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Atropine in C-section....When it become dangerous




Excessive doses of vasopressor can cause hypertension , but the increase in arterial pressure is limited by a baroreceptor-mediated reflex decrease in HR, which is more sensitive in pregnancy .

 If the vagus nerve is blocked, this protective reflex is lost and dangerously high pressures can ensue. 

 Two worrying case reports of hypertensive crises induced in women undergoing spinal anaesthesia for caesarean delivery have been reported. In both, a combination of atropine and vasopressor was given to treat bradycardia associated with hypotension, resulting in severe hypertension and tachycardia. 

 This caused acute coronary artery dissection in one  and, in the other, a myocardial infarction and pituitary haemorrhage .

 These studies suggest that when vagolytics are, quite rightly, given to treat bradycardia associated with hypotension, further vasopressor should be administered in a cautious fashion to further vasopressor should be administered in a cautious fashion to avoid hypertensive crises.
Magness RR, Rosenfeld CR. Mechanisms for attenuated pressor responses to alpha-agonists in ovine pregnancy.AmJObstet Gynecol 1988; 159:252–261.

 Newell CP, Seller C, Vizhi M, Turner N. Case report: spontaneous coronary artery dissection during elective caesarean section under spinal anaesthesia. Anaesthesia 2011; 66:615–619.
A case report of coronary artery dissection and pulmonary oedema following a hypertensive response to atropine and ephedrine given to treat hypotension associated with bradycardia in association with a background phenylephrine infusion.

 Zdanowicz JA, Utz AC, Bernasconi I, et al. Broken heart’ after caesareandelivery. Arch Gynecol Obstet 2011; 283:687–694.
A case report of a hypertensive crisis following phenylephrine and atropine given to treat hypotension associated with bradycardia, which resulted in a myocardial infarction and pituitary haemorrhage.


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  1. Gavin Doolan, AnaestricksSeptember 23, 2012 at 6:07 AM

    Unfortunately I don't have access to the journals here. I'd like to know the doses in the dissection case. Mixing alpha agonists like phenylephrine or metaraminol can give you really severe hypertension. Even without atropine. If you have been using metaraminol and then decide to add ephedrine you need to quarter your normal ephedrine dose. I'm not surprised they induced malignant hypertension with ephedrine/phenylephrine/atropine.

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