Hypotension during subarachnoid anaesthesia: haemodynamic effects of ephedrine

Abstract

We have compared the haemodynamic effects of ephedrine alone with ephedrine and colloid for the treatment of hypotension produced by subarachnoid anaesthesia in 30 patients aged 60-90 yr with fractures of the neck of femur. Group one received ephedrine as an initial bolus dose of 0.2 mg kg-1 followed by an infusion of 0.5 mg kg-1 h-1. Group two received ephedrine and colloid (polygeline, Haemaccel) 8 ml kg-1. If necessary, up to three rescue bolus doses of ephedrine (0.1 mg kg-1) and then colloid solution (8 ml kg-1) were given to maintain systolic arterial pressure (SAP) at > 75% of baseline. Arterial pressure was measured by automated oscillotonometry, central venous pressure (CVP) by a manometer and cardiac index (CI), stroke index (SI) and heart rate (HR) by transthoracic electrical bioimpedance. Systemic vascular resistance index (SVRI) was derived. In patients receiving ephedrine only, SVRI, CVP and SI decreased and HR increased (P < 0.0001). Five patients in this group required colloid, the effect of which was to restore CVP, increase CI and SI, and decrease HR (P < 0.02). In patients receiving ephedrine and colloid solution, SVRI decreased and CI, SI and HR increased (P < 0.0001). Ephedrine was not a potent arterial vasoconstrictor and SAP was maintained mainly by increases in SI and HR.

A comparison of the haemodynamic effects of intrathecal meperidine, meperidine-bupivacaine mixture and hyperbaric bupivacaïne

“…We used hyperbaric bupivacaine 15 mg for our control group, because we had used this dosage in previous studies. [27][28][29] Preloading before intrathecal injection was omitted from the study, as this would have affected our assessment of venous pressures. However, no patient was admitted to the study dehydrated and any hypotension was promptly treated.…”

A Comparison of Pre - Emptive Intramuscular Phenylphrine and Ephedrine in Prevension of Spinal Anaesthesia Induced Hypotension During Caesaerian Section

“…Ephedrine causes restoration of blood pressure mainly by increasing heart rate and contractility (direct β-agonist activity) and also by producing some vasoconstriction (indirect effect) (Critchley LAH et al 1995) 7 . Phenylephrine on the other hand, has predominant α-agonistic activity and restores the blood pressures by virtue of arterial as well as venous vasoconstriction, leading to increase in both systemic vascular resistance and venous return to the heart.…”

The Use of Intravenous Atropine After a Saline Infusion in the Prevention of Spinal Anesthesia-Induced Hypotension in Elderly Patients

“…However, rapid infusion of large amounts of IV fluid is not beneficial, and sometimes may be hazardous in patients with cardiac dysfunction (3,4). Ephedrine is also not always effective, whereas metaraminol can lead to excessive hypertension resulting from overtreatment of hypotension (5,6).…”