Evidence-based Medicine: Time for a change? - Journal of Medical ...

ORIGINAL ARTICLE
B and group C respectively. Severe pain was
experienced by a few patients in all the groups.
This distribution of pain grades is not
statistically significant with a chi-square value
of 5.40 and a P value of 0.49.
Discussion: The mechanism of propofol
injection pain is attributed to the activation of
kallikren & kinin system and the release of
bradykinin 10 . Propofol injection pain depends
on the site of injection, size of the vein, age of
the patient, temperature and concentration of
propofol or the use of tourniquet inflation 11 . The
idea of the use of tourniquet is to allow the
exertion of local anesthetic effect of lidocaine
or metoclopramide by allowing more direct
contact with the free nerve endings after
tourniquet inflation 12 . However, local
anesthetic effect is not the only mechanism
as some studies have shown that lidocaine
causes inhibition of bradykinin 10 . This may
explain why some investigators found
lidocaine mixed with propofol is superior to
pretreatment in attenuating pain 13 . In our study
we could not demonstrate significant
difference among the three groups. This is in
sharp contrast to the findings of Fujii Y and
Nakayama M 6 who found significant pain
reduction (p