EVALUATION OF PRIMING PRINCIPLE ON THE INDUCTION DOSE REQUIREMENT OF PROPOFOL
The purpose of this study was to evaluate whether ‘Priming Principle’ applied to the induction
dose of propofol would affect the total induction dose requirements and thereby reduce the
associated haemodynamic changes and pain associated with its induction. One hundred and twenty
ASA I and II patients of either sex, between 18-55years, who had elective surgeries under general
anesthesia via endotracheal intubation, were included in this study. Pregnant, lactating women,
patients allergic to propofol, patients who are hypertensive or hypotensive, those with
cardiovascular or respiratory disease and those who refused were excluded from this study.
All patients were allocated randomly by envelope method into two groups of 60 each; control
(group I) and intervention (group II) group. Patients in group I were induced with intravenous
propofol 2.5 mg/kg (calculated dose), while those in group II were initially primed with 20% of
the calculated dose of intravenous propofol and 30 seconds later induced with the remaining dose
of propofol until loss of eyelash reflex. The total induction dose, the associated haemodynamic
parameters, pain and any complications were noted and recorded at various intervals: just before
induction, one minute after induction, immediately after intubation, five, ten, fifteen and twenty
minutes after intubation. The obtained data was analyzed by chi-square test (non continuous
variables) and student’s’t’test (continuous variables).
An observation of 10% reduction in the induction dose requirement was made using the priming
principle. The systolic, diastolic and mean arterial blood pressures were more stable in the primed
group since total dose of propofol was less. Priming was also associated with less pain and
complication, with no effect on the oxygen saturation.
The result of this study revealed that applying the priming principle is effective in reducing the
induction dose requirement of propofol with minimal post-induction haemodynamic changes and