Authors Keywords: elderly, hypertension, hypotension., phenylephrine, spinal anaesthesia Abstract

Background: Phenylephrine is one of the drugs of choice in the prevention of spinal anaesthesia-induced hypotension in the elderly. The optimal dose is yet to be established in elderly patients, hence this study.

Methods: This was a randomised, double-blind study on patients aged ≥ 65 years undergoing elective lower limb and urological surgeries under subarachnoid block. A total of 57 patients were randomised into groups A, B, and C and each group contained 19 patients. Group A received 50 μg/min, group B received 75 μg/min, and group C received 100 μg/min of phenylephrine infusion immediately after the induction of spinal anaesthesia. Non-invasive blood pressure and pulse rate (PR) were recorded after the commencement of phenylephrine infusion. Onset of hypotension, episodes of hypotension, reactive hypertension, an bradycardia were recorded in each group and also compared across the groups.

Results: Hypotension was prevented without any side effects of phenylephrine in group A; one patient (5.3%) in group B had an episode of hypotension at the sixth minute. The difference in the incidence of hypotension across the groups was not statistically significant (p = 0.617). Four patients (21.1%) in group B and nine (47.3%) in group C had reactive hypertension. The difference in the incidence of reactive hypertension among groups was statistically significant (p = 0.002). Bradycardia occurred in one patient (5.3%) in group B and three (15.8%) in group C. There was no statistically significant difference (p = 0.152) in the incidence of bradycardia across the three groups.

Conclusion: The optimal dose of phenylephrine infusion that prevented spinal anaesthesia-induced hypotension without any side effects in elderly patients was 50 μg/min.

Author Biographies AB Filani, Afe Babalola University

Department of Anaesthesia and Intensive Care, Federal Teaching Hospital Ido Ekiti and Afe Babalola University, Nigeria

AF Faponle, Obafemi Awolowo University

Department of Anaesthesia and Intensive Care, Obafemi Awolowo University, Ile-Ife, Nigeria

SO Olateju, Obafemi Awolowo University

Department of Anaesthesia and Intensive Care, Obafemi Awolowo University, Ile-Ife, Nigeria

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