Clonidine Decreases Stress Response in Patients Undergoing Carotid Endarterectomy Under Regional Anesthesia: A Prospective, Randomized, Double-Blinded, Placebo-Controlled Study

Abstract

Inadequate analgesia or anxiety may induce an increased stress response in patients undergoing carotid endarterectomy (CEA) under regional anesthesia (RA). Central alpha2 adrenoceptor agonists have significant sedative and analgesic properties, which may attenuate sympathoadrenal activation during CEA and improve the quality of RA. We randomly assigned 80 patients to 2 groups receiving either RA plus placebo (n = 40) or RA plus clonidine 1 microg/kg as the initial loading dose followed by 1 microg.kg(-1).h(-1) (n = 40). RA was performed as combined deep and superficial cervical plexus blockade. Hemodynamic and neurological variables were assessed before, during, and after CEA. Arterial blood samples were collected at defined time points for the determination of plasma concentrations of epinephrine, norepinephrine, cortisol, and creatinine kinase and creatinine kinase-MB. Throughout the study, all patients responded easily to neurological evaluations. Before and during clamping mean arterial blood pressure and heart rate were not different between the groups, but mean arterial blood pressure was lower in the clonidine group (P < 0.01) at skin closure and postoperatively in the intensive care unit. In the placebo group, cortisol, epinephrine, and norepinephrine plasma concentrations were increased significantly (P < 0.05) and more patients required antihypertensive treatment (P < 0.01). Postoperatively the incidence of hypertension (P < 0.001) and development of neurological deficits (P < 0.05) was significantly decreased in the clonidine group. We conclude that 1 microg.kg(-1).h(-1) clonidine suppresses the hyperadrenergic response to CEA without adverse effects on hemodynamics or clinical neurological monitoring.

Changes in baroreceptor sensitivity after eversion carotid endarterectomy

“…All patients received 150 g of clonidine for its sedative, analgesic, and hemodynamic stabilizing effects. 20 In brief, the E-CEA technique was performed by approaching the carotid bifurcation anterior to the internal jugular vein. 21 After dividing the platysma muscle, the jugular vein was identified, and all tributaries were ligated up to the digastric muscle cranially.…”

Clonidina subaracnoidea y respuesta al trauma en cirugías cardíacas con circulación extracorpórea

“…Además de eso, la clonidina ha revelado una capacidad moduladora de la respuesta al estrés quirúrgico y la aplicación significativa en el tratamiento del dolor crónico [10][11][12][13] . Algunos estudios también sugieren que la clonidina actúa en la reducción de la morbimortalidad perioperatoria de pacientes de riesgo para coronariopatía 14,15 .…”

Avaliação do uso da clonidina para sedoanalgesia de pacientes sob ventilação mecânica prolongada, internados em unidade de terapia intensiva

“…Esses fármacos parecem ter mais efeito sedativo que analgésico 14,15 . A clonidina, um fármaco utilizado a longa data para o controle da hipertensão arterial, tem sido indicada para o controle de quadros de abstinência e para a otimização do controle da dor e da ansiedade durante procedimentos anestésicos [16][17][18][19][20][21][22][23] . Entretanto, existem poucos estudos que analisam esse fármaco como um sedoanalgésico para o controle da dor e da ansiedade dos pacientes críticos.…”

“…Esse fato pode ser importante para a evolução desses pacientes, pois se sabe que existe relação direta entre o tempo de VMI e a incidência de complicações, principalmente as infecciosas 24,25 . Os efeitos colaterais mais freqüentemente relatados na literatura em relação à administração da clonidina são a hipotensão e a bradicardia 17,19 . Apesar de estes eventos serem geralmente brandos e previsíveis, são responsáveis pela resistência de grande parte dos médi-cos intensivistas quanto à utilização dos α 2 -agonistas.…”

“…Mostraram que a clonidina diminuiu a incidência da mortalidade desses pacientes. Schneemich e col. 32 apontaram que a clonidina suprime a resposta hiperadrenérgica em pacientes submetidos a endarterectomia de carótica. Von Dossow e col. 33 , por considerarem que os linfócitos T desenvolvem um papel central na resposta imunológica ao trauma, avaliaram 40 pacientes submetidos à cirurgia cardíaca.…”