Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Cardiovascular Anesthesia
INTRODUCTION: Conventional open abdominal aortic reconstruction (OAR) may be associated with significant hemodynamic instability. Previous work have demonstrated improved hemodynamic stability in patients undergoing endovascular aortic repair (EAR) compared with OAR: however, these studies were limited because a limited number of discrete intervals were examined. [1,2] In this study we examined overall hemodynamic stability in patients undergoing EAR compared with OAR.
METHODS: The study was approved by the IRB. Heart rate, mean arterial pressure, and mean pulmonary arterial pressure were extracted (every 15 seconds) from computerized anesthesia records for 72 OAR and 15 EAR procedures for a maximum of 5 hours. The median value of each hemodynamic parameter was calculated for every 2 minute epoch in order to filter for artifact, and the absolute value of the fractional change in median ([vertical bar]FCM[vertical bar]) from epoch to epoch was calculated. The proportion of [vertical bar]FCM[vertical bar]>0.06 was used as an index of lability as previously validated.  Additionally, the proportion of the procedure in which the 2-minute median data were outside of specified normal ranges was calculated. The data were compared between groups using the Mann-Whitney U test. A two-tailed p<0.05 was considered significant.
RESULTS: EAR cases were significantly more stable hemodynamically than OAR for all three parameters. The data are presented in Table 1. There were no statistically significant intergroup differences in the proportion of each patients' procedure in which hemodynamic parameters were outside of specified normal ranges.
DISCUSSION: EAR is a minimally invasive procedure which offers many advantages over OAR. The need for mesenteric and retroperitoneal dissection are eliminated and no aortic cross clamp is required. The use of epidural anesthesia and the potential for hemorrhage, however, do not eliminate the risk of intraoperative hemodynamic instability. Our results demonstrate improved hemodynamic stability associated with EAR in comparison with OAR, implying that these procedures may be safer for high risk patients.
1. Br J Anesth 1997;78:A104.
2. Anesth Analg 1997;84:SCA79.
3. Anesthesiology 1997;87:156-61.