A comparative study of three different methods of administering metaraminol during spinal anaesthesia in the elderly.
We compared three methods of administering metaraminol during spinal (subarachnoid) anaesthesia. Fifty-two elderly patients with fractured hips were studied. Blood pressure was maintained by either intramuscular (i.m.) metaraminol (0.1 mg x kg(-1)), intravenous (i.v.) boluses (0.01 mg x kg(-1)) or an infusion (0.05 mg x kg(-1) x h(-1)). Non-invasive blood pressure was recorded every one-minute. Spinal anaesthesia initially decreased the systolic arterial pressure by 15 (14) % compared to 35 (15) % for diastolic pressure (P<0.001). I.m. metaraminol restored the systolic arterial pressure back to baseline values (-3%), but there was significant between-subject variability resulting in a very unpredictable effect. I.v. boluses and infusion had a more predictable effect and maintained systolic arterial pressure at about 20% below baseline. Range of effect, measured by inter-quartile range and variance, was greatest in the i.m. group and least in the infusion group (P<0.003). I.m. metaraminol during spinal anaesthesia has a very unpredictable effect. Infusions of metaraminol provided the best blood pressure control. Diastolic blood pressure fell significantly after spinal anaesthesia and this merits further investigation.
Critchley
L A
LA
Department of Anaesthesia & Intensive Care, Chinese University of Hong Kong and Prince of Wales Hospital, Shatin, New Territories, SAR.
Yu
S C
SC
D000368:Aged; D000369:Aged, 80 and over; D000775:Anesthesia, Spinal / Q000009:adverse effects; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006620:Hip Fractures / Q000601:surgery; D006801:Humans; D007022:Hypotension / Q000517:prevention & control; D007262:Infusions, Intravenous; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D007431:Intraoperative Complications / Q000517:prevention & control; D008297:Male; D008680:Metaraminol / Q000008:administration & dosage*; D014662:Vasoconstrictor Agents / Q000008:administration & dosage*
D014662:Vasoconstrictor Agents; D008680:Metaraminol