Thoracolumbar epidural blockade as adjunct to high dose fentanyl/midazolam anesthesia in coronary surgery: effects of sternotomy

Abstract

The present study tests the hypothesis that the changes in myocardial lactate metabolism in the early period of coronary surgery are caused by raised adrenergic activity, and that these are preventable by the addition of thoracolumbar epidural blockade to high dose fentanyl/midazolam anesthesia. Twenty-seven male beta 1-blocked patients undergoing coronary surgery were included in a prospective, controlled, randomized study. High dose fentanyl/midazolam anesthesia alone (control) or supplemented with thoracolumbar epidural blockade (treatment) was used. Measurements were performed before the induction of anesthesia and after sternotomy. After sternotomy adrenaline (A) and noradrenaline (NA) had decreased and were both in the low range, especially in the epidural group (P < 0.01). Arterial pressures decreased in both groups, especially in the epidural group, where coronary perfusion pressure (CPP) decreased from 61 (42-88) to 48 (33-64) mm Hg; Systemic vascular resistance (SVR) decreased with 30% in the epidural group (P < 0.01), but not significantly in the control group. The myocardial fractional extraction of lactate decreased in both groups, from 33 (10-45) to 13 (0-42)% in the control group (P < 0.01), and from 36 (19-43) to 10 (2-20)% in the epidural group. It is concluded that high dose fentanyl/midazolam anesthesia prevents hyperadrenergic activity in the early phase of coronary surgery, but cannot eliminate changes in myocardial lactate metabolism. The addition of the thoracolumbar epidural blockade to high dose fentanyl/midazolam anesthesia offers no obvious benefits in the early phase of coronary surgery.

Thoracic epidural analgesia and coronary artery bypass graft surgery

“…Prospective randomised controlled trials have failed to show any real advantage in terms of outcome and recovery parameters conferred by the addition of thoracic epidural anaesthesia to medium or lower dose opioid‐based general anaesthesia in patients undergoing coronary artery bypass graft [7–9]. Similar earlier studies have shown that patients receiving epidural infusion for intra‐ and postoperative analgesia exhibited significantly increased pulmonary capillary wedge pressure [10], significant decrease in arterial blood pressure and in coronary perfusion pressure [11], and suppressed cortisol response [12] when compared with patients without epidural analgesia.…”

Die thorakale Epiduralanästhesie - mehr als ein Anästhesieverfahren

“…"cold pressor test", bei welchem durch Eintauchen des Unterarms in eiskaltes Wasser eine starke sympathoadrenerge Abb.2 ᭡ Wirkung einer Sympathikusstimulation durch den "cold pressor test" auf den Durchmesser von Koronararterien bei Patienten mit koronarer Herzerkrankung. Lediglich in einer Untersuchung werden keine unterschiedlichen Resultate bei Patienten mit und ohne TEA während einer Bypassoperation beschrieben[118]. Demgegenüber tritt bei angiographisch auffälligen Koronargefäßen eine paradoxe Vasokonstriktion auf, so daß bei Sympathikusaktivierung ein "coronary steal" auftreten kann.…”