[Esmolol as a bolus for prevention of sympathetic adrenergic reactions following induction of anesthesia].
In addition to laryngoscopy, endotracheal intubation, and other stressful intraoperative phases, hypertension occurs during recovery from anaesthesia, provoking post-operative complications like bleeding and increased intracranial or intraocular pressure. Furthermore, these hypertensive reactions result in life-threatening complications, especially in patients with pre-existing cardiovascular diseases. In this study, the effect of the new, short-acting beta-blocker esmolol given as a single bolus for preventing the increases in blood pressure and heart rate during recovery from anaesthesia and extubation in patients with hypertension was investigated. PATIENTS AND METHODS. Sixty-three patients with a history of hypertension over a period of more than 6 months and blood pressure (BP) more than 150/90 mm Hg undergoing intervertebral-disc, otolaryngologic, or eye surgery were included in the study. The operations were performed during thiopentone-induced isoflurane anaesthesia with relaxation by atracurium. The patients were assigned to three groups after giving witnessed oral informed consent. During the study period they received the study drug twice: (A) 30-90 s before turning off the nitrous oxide; and (B) 20-90 s before extubation. Group I (placebo) received placebo each time, group II (100 mg esmolol) placebo at A and 100 mg esmolol i.v. at B, and group III (200 mg esmolol) 100 mg esmolol i.v. each time. After each medication the cardiovascular parameters were measured noninvasively over a period of 10 min every minute and in the following 2 h every 15 min. RESULTS. After the first medication systolic and diastolic BP, heart rate (HR), and rate-pressure product (RPP) were lower in patients receiving 100 mg esmolol (Group III) than in groups I and II. After the second injection the blood pressure was lower in the two groups receiving 100 mg esmolol, than the placebo group (I: 180.1 +/- 7.4/100.7 +/- 3.6; II: 152.8 +/- 5.8/87.9 +/- 3.4; III: 157.9 +/- 5.3/91.5 +/- 3.6 mm Hg [mean 2 min +/- SEM]). The changes in HR (I: 88.2 +/- 3.8; II: 75.6 +/- 2.6; III: 72 +/- 3.1 min-1) and RPP (I: 15,800 +/- 900; II: 11,700 +/- 700; III: 11,400 +/- 600) were similar. In 8 of the 20 patients in group III the HR dropped below 60.min-1, but in none of these patients did the BP become instable. CONCLUSIONS. The sympathoadrenergic reaction during recovery from anaesthesia and extubation can be treated by beta-blocking agents, but such therapy is not without risk because of the long half-life and effects of the therapy on other factors such as postoperative loss of intravascular volume. Esmolol is a new, short-acting, cardioselective beta-blocker with a very short plasma distribution time and a elimination half-life of 9.2 min. Thus, the potential risks of beta-blockers due to half-life are minimised. The results of this study show that a dangerous increase in BP and HR with increased myocardial oxygen consumption can be prevented by a single bolus, and better by a double bolus of 100 mg esmolol. Although bradycardia with HR below 50.min-1 in 8 patients might indicate a risk of cardiac instability, the systolic BP did not fall below 100 mm Hg, and the episode of bradycardia was so short that there was no risk to the patients.
Abteilung Anästhesiologie II, Medizinische Hochschule Hannover.
J
J
Schäffer
C
C
Karg
S
S
Piepenbrock
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000762:Anesthesia Recovery Period; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011412:Propanolamines / Q000008:administration & dosage / Q000627:therapeutic use*; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; C036604:esmolol
Esmolol als Bolus zur Prophylaxe der sympathikoadrenergen Reaktion während der Narkoseausleitung.