Perioperative use of α2-adrenoceptor agonists and the cardiac patient

Abstract

The centrally acting alpha2-adrenoceptor agonists clonidine and dexmedetomidine have been used with success to provide haemodynamic stability for patients undergoing surgery. Particularly in the case of patients with overt or underlying cardiac disease the actions of alpha2-adrenoceptor agonists, which include maintenance of stable systemic blood pressure and low heart rate and a reduction in overall oxygen consumption, can be expected to reduce the risk of procedure-related cardiac events. This expectation has been corroborated in clinical trials with clonidine, dexmedetomidine and mivazerol and meta-analyses; additional large controlled trials would be instructive in establishing a robust estimate of the scale of the benefit. In addition, alpha2-adrenoceptor agonists used as premedication have been shown to substantially reduce anaesthetic requirements among surgical patients, and the use of these agents has been associated with a reduced risk of postoperative delirium, which may be expected to improve considerably the postoperative course for at-risk patients. Dexmedetomidine is the only alpha2-adrenoceptor agonist currently approved for use in the intensive care unit. A distinctive feature of dexmedetomidine in that setting is that in addition to haemodynamic stability it confers a distinctive and advantageous quality of sedation: patients are tranquil but responsive to requests from attending staff. This review examines the pharmacological principles underlying the use of alpha2-adrenoceptor agonists as adjuncts to surgery and clinical experience in that indication.

Comparative clinical study of the effect of oral clonidine premedication on intraoperative haemodynamics in the patients undergoing laparoscopic cholecystectomy

“…24 Though mainly used as an anti-hypertensive agent, it has many properties of an ideal premedicant and also has beneficial effects on haemodynamics during stressful conditions like laryngoscopy and endotracheal intubation Clonidine, an imidazoline derivative, is well absorbed when given orally and is completely used in the body. The pharmacological effect of Clonidine appears in 1.5-2 hours, with the peak level in 3 hours.…”

“…The pharmacological effect of Clonidine appears in 1.5-2 hours, with the peak level in 3 hours. 23,24 This double blind prospective randomized study was undertaken to evaluate effectiveness of oral Clonidine as a pre-anaesthetic medication and as a drug to attenuate the peri-operative haemodynamic alterations during laparoscopic cholecystectomy.…”

Effects of Dexmedetomidine Sedation on Myocardial Ischemia in Peripheral Vascular Surgery Performed Under Epidural Anaesthesia

“…Bu etki daha çok α2-agonistlerin santral etkisi ile açıklanmaktadır (3) . Plasebo ve remifentanil gibi kısa etkili opioidlerle karşılaştırıldığı çalışma-larda, deks postoperatif analjezik tüketimini anlamlı olarak azaltmıştır (26,27) .…”

“…Yol açtığı anksiyoliz ve amnezi nedeniyle midazolam çoğunlukla tercih edilmektedir. Deksmedetomidin (deks) ise selektif bir alfa-2 agonist olup sedatif ve sempatolitik özellikleri ile genel ve rejyonel anestezi uygulamalarında yardımcı ajan olarak kullanılmış-tır (3) . Analjezik etkisi ve anesteziklerin kullanımını azalttığı önceki yayınlarda gösterilmiştir (4,5) .…”

Hemodynamic Effects of Levosimendan on Dexmedetomidine Infusion in Rats Under Isoflurane Anesthesia

“…12 Ickeringill ve ark. toplam 50 hastayı içeren çalışmalarında, çalışmamızdaki metodolojiye benzer şekilde yükleme dozu uygulamadan, deksmedetomidin infüzyonunun etkilerini araştır-mışlar, 0,2-0,4 µg/kg/sa dozlarında uygulanan deksmedetomidinin KAH'ı anlamlı olarak azalttığını ve SAB'ı ise anlamlı olarak düşürdüğünü bildirmişler-dir.…”