European Journal of Biomedical and Pharmaceutical Sciences

EFFECTS OF MIDAZOLAM ON THE SPINAL CORD BLOOD FLOW DURING HYPOVOLEMIC SHOCK IN CATS

Tomoki Nishiyama*

ABSTRACT

The purpose of this study was to investigate the changes of spinal cord blood flow by midazolam in hypovolemic shock in the cat model. Twelve male cats of 2.5 to 3.5 kg body weight were tracheotomized and ventilated to keep end-tidal carbon dioxide (CO2) tension between 30 and 35 mmHg under 1.5% isoflurane in 40% oxygen. The cats were fixed in a stereotaxic apparatus, and L1 to L5 were laminectomized to expose the spinal cord. A platinum electrode was stereotaxically inserted into the spinal cord to a depth of 1 mm at 2 mm lateral of the midline at L2. The spinal cord blood flow was measured with a hydrogen clearance method. Immediately after the intravenous administration of normal saline 5 mL including (Midazolam group, N=6) or without (Control group, N=6) midazolam 1 mg/kg, arterial blood was drawn to decrease blood pressure to the half of the control value in 5 minutes. The low blood pressure was kept for 30 minutes, and then all drawn blood was re administered in 10 minutes. Blood pressure, heart rate, and spinal cord blood flow were measured until 30 minutes after the return of the blood. Spinal cord blood flow decreased by blood drawn in both groups but to a lesser extent in the Midazolam group during shock phase and at 30 minutes after blood return. In conclusion, during hypovolemic shock by bleeding, midazolam attenuated the decrease of the spinal cord blood flow.

Keywords: Benzodiazepine, Midazolam , ischemia, bleeding, spinal cord, blood flow.