• J Thorelius, O Wesslén, J A Björkman, R Ekroth, P O Joachimsson, G Ronquist, and H Tydén.
• Department of Thoracic and Cardiovascular Surgery, University Hospital, Uppsala, Sweden.
• Eur J Cardiothorac Surg. 1993 Jan 1; 7 (4): 181-5.

AbstractTo evaluate the relationship between the hemodynamic and ECG variables used in routine surveillance of coronary surgery and myocardial lactate metabolism, 23 middle-aged, male, beta 1-blocked patients about to undergo coronary surgery were monitored before and after endotracheal intubation with high dose (30 micrograms/kg) fentanyl-midazolam anesthesia. The induction of anesthesia was followed by a mean arterial pressure decrease (from 98 +/- 4 to 76 +/- 3 mm Hg) and heart rate increase (from 53 +/- 3 to 66 +/- 2 beats/min). After intubation the hemodynamic variables were stable except for a further, transient increase in heart rate (to 69 +/- 2 beats/min). The myocardial uptake of lactate decreased after intubation, from 48 +/- 5 mumol/min to a lowest level of 24 +/- 3 mumol/min. A lactate release was exhibited in 7/23 patients (30%). No ST-segment changes were observed. The correlation between the myocardial lactate uptake/release and hemodynamic or ECG variables was unimpressive or non-existent (r < or = 0.20). Thus, a reduced uptake and even a release of lactate occurred irrespective of the ST-segment, heart rate, or systemic or pulmonary artery pressures. In conclusion, endotracheal intubation in patients with coronary disease was consistently (17/23 patients) followed by a reduced myocardial uptake of lactate, in spite of high dose neurolept anesthesia and beta 1-blockade. This metabolic event was not consistently related to hemodynamic changes.

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