Purpose: This study was conducted to test the hypothesis that clonidine produces a dose-dependent increase in the sweating threshold and dose-dependent decreases in vasoconstriction and shivering thresholds. Methods: Six healthy subjects (two female) were studied on four days after taking donidine in oral doses of either 0 (control). 3, 6 or 9 ~g. k,g ~ . The order followed a balanced design in a double-blind fashion. Oesophageal temperature and mean skin temperature (from t 2 sites) were measured. Subjects were mated in 37~C water which was gradually warmed until sweating occurred (sweat rate increased above 50 g-m-2h -~). The water was then cooled gradually until thresholds for vasoconstriction (onset of sust~ned decrease in fingertip blood flow) and shwering (sust~ned elevataon in metabolism) were determined. Thresholds were then referred to as the core temperature, adjusted to a designated mean skin temperature of 33~ Results: High dose clonidine similarly decreased the adjusted core temperature thresholds Objectif : VErifier s~ la clonidine provoclue une augmentataon du seuil de sud~on et une diminution des seuils de vasoconstnctaon et de fnsson propo~onnellement ,~ la dose. M&hodes : Six patients en bonne santE (dont deux femmes) qui avalent re~u des doses orales de donidine de 0 (contr61e), 3, 6 et 9 gg-kg ~ ont Et~ EtudiEs pendant quatre jours. IJEtude suivait un plan Equilibr~ et en double insu. Les temperatures moyennes oesophagiennes et cutanEes (~ 12 endro~s) ont &E mesur6es. Les sujets &aient assis darts reau ~ 37~ r&hauff& graduellement jusqu'~ I'apparition de la sudation (un taux de sudataon ;~ 50 g.m 2.h-a). Eeau C~tait par la suite refroidie progressivement jusqu'aux seuils de vasoconstriction (dEbut de la diminution du flux sanguin ,~ rextrEmrt(~ des doigts) et de fnssonnement Ces seuils ont ErE reconnus comme la temperature centrale ajustEe ~ une temp6rature cutan6e d6sign6e de 33~ R~uitats : Les hautes doses de clonodine abaJssent Egalement les seuils de vasoconstriction ajust6s ,~ la temperature centrale de I. 16 + 0,30~ et du frissonnement de 1,63 + 0,23C (P < 0,01). Les effets dose-rEponse sont linEaires pour les deux rEponses au froid avec des seuils de vasoconstriction et de frissonnement diminuant respectivement de 0, 13 -+ 0,05 et de 0,19 • 0,09~C'~g t (P < 0,0001 ). Le seuil de sudation n'est pas affectE par le donodine ; toutelois r&art entre les seuits de sudation et de vasoconstriction s'Elargit entre le contr6he (0,19 _+ 0,48~ et la clonodine haute dose (I.31 _+ 0,54~ Conclusion : La baisse des seuils de la temperature cent~le pour les rEponses au frc~d et I'augmentation de I'&art entre les seuils sont consist,ants avec tes effets de plusieurs agents anesth&iques et morphiniques et d~montrent une inhibition de la thermor~gulation centrale.

Most anesthesiologists defined low PAP as the primary strategy of LPV during OLV and attempted to minimize it. This study is the first to assess the practice/perspectives of anesthesiologists regarding LPV during OLV and also the first to explore predictors of LPV use. Randomized trials are currently ongoing. However, this study suggests that institutional barriers may subvert future knowledge translation and need to be addressed.

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Introduction: This chart review was a quality improvement project to compare three epidural solutions that have been used at a tertiary care academic hospital. The three solutions compared were (1) 0.1% Bup./Dilaudid 20ug/cc, (2) 0.125% Bup./Dilaudid 20ug/cc and (3) 0.125% Bup./Fentanyl 2ug/cc. Methods: Local REB approval was obtained for this study. Retrospective Chart Review of Patients that had undergone elective AAA or Thoracic Surgery (Lobectomy, Pneumonectomy) with preoperative placement of an Epidural catheter. Medical Records generated a list from May, 2005 to July, 07'; patients were selected continuously until at least 200 met inclusion criteria. End points included hypotension (SBP <90 mmHg at least 60 min apart), fluid requirements, mean pain scores, mean infusion rates and side effects. Results: See Table 1 Discussion: There was only one significant difference in baseline characteristics between groups, which was slightly less ASA 4 patients in Thoracic group (3). There was no difference in significant outcomes including MI, arrhythmia or acute renal failure. The significant differences in infusion rates demonstrated that a higher volume of 0.125 Bup/F. was required for adequate analgesia. The likely explanation for the significant difference in mean pain scores in the Thoracic group (1) was the more potent Dilaudid over Fentanyl and that in group (2) infusion was held for a longer time period when hypotension occurred. Among AAA patients, pain scores were actually higher with the most potent solution (2), this appears to correlate with the significant difference in this solution being held for hypotension. There was a higher incidence of nausea and vomiting in Thoracic patients recieving solutions with Dilaudid, however this difference was not seen in AAA patients. Many other combinations of local anesthetic and an opioid are possible; several studies have looked at different combinations, their effects on pain control and side effects [1][2][3]. However, few studies have looked at incidence of hypotension. It appears that changing to lower concentration of Bup. along with a less soluble more potent opioid, resulted in better post op pain control and a trend toward less hypotension. This information has lead to a change to solution (1) at this institution.

Accurate positioning of thoracic endografts in the aortic arch and the proximal descending thoracic aorta can be difficult because of the tortuous arch anatomy and the hemodynamic forces therein. Adjunctive measures are necessary and include pharmacological interventions as well as rapid ventricular pacing and right-atrial-inflow occlusion. Endograft design advances have also been instrumental in increasing the applicability of this technology to the arch. These adjunctive measures are subsequently described.