Abstract

Background:Spinal anesthesia is a common choice for patients undergoing orthopedic
surgeries.ondansetron was found to attenuate the incidence of SIH and bradycardia during
spinal anesthesia.
Aim of the study:This work was done to compare between the effects of prophylactic
intravenous of two different doses of ondansetron (4 mg) and (8 mg) in attenuating hypotension
in patients undergoing orthopedic surgeries under spinal anesthesia.
Patients and methods:This study wasa prospective comparative randomized controlled clinical
trial that have been carried out in Zagazig University Hospitals and included 66 patients, their
ages ranged from 21 to 60 years old patients for only unilateral orthopedic surgeries under
spinal anesthesia, duration of surgery less than 2 hours in the study.Patients were randomly
divided into three equal groups, 22 patients for each group, Group "O1" received IV
ondansetron (4mg) diluted in 10 ml saline, group "O2" received IV ondansetron (8mg) diluted
in 10 ml saline, and group C (control) received only 10 ml IV saline alone. Medications were
administrated 5 min before starting the subarachnoid block by an anesthesiologist blinded to
them, they were assessed for their cardiovascular effects including blood pressure, heart rate
(HR) before, throughout and after operation.
Results:There was difference between the prophylactic intra venous of the two different doses
of ondansetron in attenuating hypotension in patients undergoing orthopedic surgeries, under
spinal anesthesia compared with the control group. Mean Blood Pressure (MBP) and HR were
significantly, lower among the control group from 5 min tell the 10 minutes compared to (O1)
and (O2) groups.
Conclusion:
In patient undergoing orthopedic surgeries under spinal anesthesia, prophylactic intravenous
administration of 4mg ondansetron or 8mg ondansetron 5min before induction of spinal
anesthesia to reduce the severity of spinal-induced hypotension and bradycardia well
significantly.