Abstract
During anesthesia for orthognathic surgery, deliberate hypotensive anesthesia is often used to reduce bleeding and provide a satisfactory bloodless surgical field. However, predicting whether deliberate hypotension can be controlled effectively is difficult. The purpose of this study was to investigate factors influencing the stability of deliberate hypotension.
Patients who underwent orthognathic surgery under total intravenous anesthesia with deliberate hypotension using sodium nitroprusside (SNP) between January 2011 and December 2014 were included in this study. Each patient’s age, sex, mean blood pressure (MBP) after hospital admission, MBP upon arrival in the operating room, and MBP after the induction of anesthesia (MBPIA) were retrospectively extracted from their anesthesia records. The MBPs, bispectral index value, fentanyl dose, remifentanil infusion rate, and SNP infusion rate (SNPDH) were also recorded for a 30-minute period of deliberate hypotension at between 10 and 40 minutes after the initiation of continuous SNP. A mean 30-minute MBP value of between 50 mmHg and 65 mmHg and a maximum value of less than 80 mmHg were defined as stable results ; other values were considered unstable. A multivariable logistic regression analysis was performed with the stability of deliberate hypotension as the primary outcome.
A total of 223 patients were divided into the stable group (n=121) or the unstable group (n=102). The surgical method (odds ratio=2.15 ; 95%CI, 1.07-4.33 ; p=0.031), MBPIA (odds ratio=0.96 ; 95%CI, 0.93-0.99 ; p=0.008), and SNPDH (odds ratio=0.07 ; 95%CI, 0.01-0.58 ; p=0.013) were independently associated with the stability of deliberate hypotension.
During orthognathic surgery, a high blood pressure after anesthetic induction was found to be associated with the unstable management of deliberate hypotension.
