Effects of three different methods of anesthesia on the release of brain natriuretic peptid in patients with cardiac risk undergoing lower extremity surgery

Authors: CANAN ATALAY, CELALETTİN DAĞLI, EDNAN BAYRAM, HACI AHMET ALICI, ALİ FUAT ERDEM, MEVLÜT SAİT KELEŞ, ŞAHİN YÜKSEK

Abstract: To investigate if intra and postoperative thoracal epidural analgesia could decrease plasma concentrations of brain natriuretic peptide (BNP) in patients who were at risk for, or had, coronary artery disease (CAD) and undergoing lower extremity operations. Materials and methods: Sixty patients with risk of CAD scheduled to undergo lower extremity surgery were divided into 3 groups. Group G was administered general anesthesia followed by intravenous patient-controlled analgesia (I.V PCA) (n = 20). Group L was administered lumbar epidural anesthesia followed by lumbar epidural analgesia (n = 20). Group T was administered general anesthesia combined with intra and postoperative thoracal epidural analgesia as well as I.V PCA (n = 20). Visual analog scale pain scores, hemodynamics, plasma catecholamines, cardiac troponin I (cTnI), atrial natriuretic peptide (ANP), and BNP were measured preoperatively and measurements were extended to 90 min after skin incision, towards the end of surgery, and in the morning of day 1, 2, and 3 postoperation. The data were statistically compared using multiple comparison tests. Results: Baseline ANP and BNP concentrations were similar in all groups (G: 25.8 ± 4.51 and 25.9 ± 8.52 pg/mL; L: 23.9 ± 3.67 and 20.8 ± 9.8 pg/mL; T: 24.7 ± 4.27 and 23.0 ± 5.98 pg/mL, respectively). The postoperative plasma BNP concentrations of group T were lower than those of groups L and G. and similarly group L was lower compared to group G in terms of postoperative plasma BNP concentrations (P < 0.05). Peak plasma concentrations of BNP were 162.4 ± 29.4, 110.6 ± 12.2, and 69.0 ± 6.9 for groups G, L, and T, respectively (P < 0.05). However, there was no group difference in peak plasma ANP concentrations. Baseline epinephrine and norepinephrine concentrations were also similar across the groups. Peak plasma epinephrine concentrations of group T were lower than those of groups G and L (P < 0.05). Plasma cTnI concentrations were within normal limits (<0.1 µg/L) in all the 3 groups and no difference in plasma cTnI was observed among the groups throughout the study (P < 0.05). The plasma cTnI concentration did not correlate with either the ANP or BNP concentration in each group. Conclusion: Lower plasma BNP level for patients in group T comparing with patients in other groups and in group L compared to group G may suggest that opioids and local anesthetics could contribute to the positive effects of thoracal epidural analgesia and lumbar epidural anesthesia plus analgesia through inhibition of BNP release.

Keywords: BNP, thoracal epidural analgesia, lumbar epidural anesthesia

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