Background:Side effects of spinal anesthesia are hypotension, bradycardia and shivering. Five-hydroxytriptamine (5-HT), a serotonergic receptor, may be an important factor associated with inducing the Bezold Jarish reflex (BJR) that may lead to the bradycardia and hypotension in the setting of decreased blood volume.Objectives:This study aimed to investigate the effect of intravenous administration of ondansetron, a 5-HT3 receptor antagonist, which could attenuate spinal-induced hypotension, bradycardia and shivering.Patients and Methods:Two hundred and ten patients aged 20-50 years old were scheduled for spinal anesthesia and were divided randomly into three equal groups. The control group received normal saline and intervention groups received 6 mg or 12 mg of intravenous ondansetron 5 minutes before spinal anesthesia. Mean arterial pressure (MAP), heart rate (HR), and shivering were recorded before and after spinal anesthesia every 5 minutes during first 20 minutes of surgery.Results:Demographic data were not statistically different among groups. HR was statistically different between the experimental groups and the control group. Ten patients (14%) in the control group had HR < 50 bpm, that required intravenous atropine compared to experimental groups (P =0.02). In the control group 12 (17%) patients had MAP < 80 mm Hg and required vasopressors compared to experimental groups (P = 0.04). There were no significant differences in MAP and HR between the experimental groups (P =0.06). Incidence of shivering in the control group was 45% (32.70) that was statistically more than experimental groups (P = 0.02).Conclusions:Administration of two different doses of intravenous ondansetron, 6 mg and 12 mg, significantly attenuates spinal induced hypotension, bradycardia and shivering compared to the control saline group. However, the hemodynamic profiles and shivering in experimental groups were not statistically different.

Background:previous evidences suggested that traditional sitting position (flexion of knees approximately 90°, and adduction of hips while feet rest on a stool) and hamstring stretch position (sitting position with maximum extension of knees, adduction of hips, and forward bending) both reversed the lumbar lordosis and the number of spinal needle-bone contacts were identical when placing patients in these positions for neuraxial block.Objectives:In this study, we suggested that squatting position reverses the lumbar lordosis and reduces the number of spinal needle bone contacts better than a traditional sitting position.Patients and Methods:Two hundred and thirty six patients ASA (American Society of Anesthesiologist) class I or II aged 18 to 75 years scheduled for elective surgeries under elective spinal anesthesia were randomized into two groups. We compared the traditional sitting and squatting positions. Our primary endpoint was the number of spinal needle-bone contacts, and secondary endpoint was ease of needle insertion or space identification.Results:The total number of spinal needle bone contact was statistically lower in the squatting position compared to traditional sitting position group (222 versus 230 respectively, P = 0.01). Insertion of needle was easy in 97 (87%) and 94 (84%) of patients and difficult in 20 (18%) and 17 (15%) of patients in traditional sitting and squatting positions, respectively (P = 0.59 and P = 0.12). Needle insertion was not impossible in any patients.Conclusions:In squatting position the number of spinal needle-bone contacts was lower compared to the traditional sitting position, nonetheless ease of needle insertion or space identification was the same in the both groups.

Prophylactic fibrinogen reduces post-operative bleeding in patients undergoing coronary artery bypass graft.