Background: Induction of anaesthesia with propofol is often
associated with a significant decrease in arterial pressure,
especially in the older population. The aim of this study is to
determine the efficacy of phenylephrine in two different
doses i.e. 100mcg and 200mcg, given during induction to
counteract the anticipated hypotensive effect of propofol in
older patients aged over 55 years.
Methods: Seventy-two ASA physical status I – II patients
aged 55 years or older were randomly allocated to group 1
(received propofol mixed with normal saline), group 2
(propofol mixed with 100mcg of phenylephrine) or group 3
(propofol mixed with 200mcg of pheynylphrine).
Anaesthesia was induced with fentanyl 1.5mcg/kg and
propofol 2mg/kg (mixed with the study drug). Systolic blood
pressure (SBP), diastolic blood pressure (DBP), mean
arterial pressure (MAP) and heart rate (HR) were recorded at
1 minute intervals for up to 5 minutes after induction.
Results: SBP, MAP and DBP decreased significantly after
induction in the control group and group 2 (phenylephrine
100mcg). In contrast, SBP was maintained to near baseline
for the first two minutes after induction using phenylephrine
200mcg in group 3, and similar trends were seen with MAP
and DBP at a lesser magnitude.
Conclusion: Phenylephrine 200mcg is more effective than
100mcg in attenuating propofol induced hypotension,
especially during the first two minutes after induction, in
patients aged 55 years and above.
Phenylephrine
;
Propofol