Induced Hypotension Using Esmolol in Spinal Surgery

Do, Sang Hwan; Lee, Jin Ho; Kim, Ji Ae; Kim, Chong Soo; Oh, Yong Seok; Ko, Hong; Kim, Yong Lak

Abstract

Background: Esmolol as a drug for induced hypotension can, not only avoid many drawbacks of nitroprusside, but reduce the amount of intraoperative bleeding and make better operative field. This study was performed to evalute cardiovascular changes during esmolol-induced controlled hypotension.
Methods
Induced hypotension using esmolol was applied to 18 adult patients receiving spinal surgery under the diagnosis of spinal stenosis or scoliosis. After prehydraion of 2,000 ml of crystalloid solution, 0.5 mg/kg esmolol was used as loading dose once, twice or three times until mean blood pressure (MBP) fell below 70 mmHg, followed by continuous infusion (50~300 microg/kg/min) of esmolol. MBP and heart rate (HR) were measured before, 5, 10, 15, 30, 60 and 90 min after esmolol administration, and 5, 10 and 15 minutes after discontinuation of esmolol. In 8 patients, cardiac output (CO) and mixed venous oxygen tension and saturation were measured before, during and after esmolol use.
Results
MBP was decreased from 91+/-12 mmHg to 67+/-7 mmHg after 15 min (P<0.05). HR(BPM) was decreased from 76+/-17 to about 60 after 15 min (P<0.05). CO was decreased about 30% during induced hypotension but recoverd to initial level 15 min after esmolol discontinuation. While oxygen transport was reduced significantly during induced hypotension (P<0.05), oxygen consumption was maintained all the time.
Conclusion
With the use of esmolol, stable hypotension could be achieved. Although oxygen transport decreased possibly due to reduction of CO, but oxygen consumption was maintained.