Intramuscular Ephedrine in the Prevention of Hypotension in Patients Undergoing Spinal Anesthesia

Subarachnoid anesthesia is an alternative and usually the first choice for many surgical procedures. It is a simple and safe procedure, however it can present complications such as hypotension and bradycardia. In this sense, ephedrine, an alpha and beta agonist agent, commonly used as rescue therapy for these events, is also potentially useful for prophylaxis of this unwanted effect and for less hemodynamic variation when preventively administered via the intramuscular route. Two groups will be divided: intramuscular ephedrine (0.5 mg/kg) and placebo. The variables analyzed and compared will be the incidence of hypotension and bradycardia, variation in mean and systolic blood pressure, heart rate, in addition to side effects. The main objective is to verify if the use of intramuscular ephedrine prior to spinal block is able to reduce the incidence of hypotension.