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Both intravenous dexamethasone and dexmedetomidine prolong the analgesic duration of interscalene blocks (ISB) after arthroscopic shoulder surgery. This study compared their relative effectiveness and the benefit of their use in combination.This single-centre, double-blinded, parallel three-group superiority trial randomized 198 adult patients undergoing ambulatory arthroscopic shoulder surgery. Patients received preoperative ISB with 30 mL 0.5% bupivacaine and 50 µg dexmedetomidine or 4 mg dexamethasone or both of these agents as intravenous adjuncts. The primary outcome was analgesic block duration. Secondary outcomes included the quality of recovery 15 score (range: 0-150) on day 1 and postoperative neurologic symptoms in the surgical arm.Block durations (n = 195) with dexamethasone (median [range], 24.5 [2.0-339.5] hr) and both adjuncts (24.0 [1.5-157.0] hr) were prolonged compared with dexmedetomidine (16.0 [1.5-154.0] hr). When analyzed by linear regression after an unplanned log transformation because of right-skewed data, the corresponding prolongations of block duration were 59% (95% confidence interval [CI], 28 to 97) and 46% (95% CI, 18 to 80), respectively (both P0.001). The combined adjuncts were not superior to dexamethasone alone (-8%; 95% CI, -26 to 14; P = 0.42). Median [IQR] quality of recovery 15 scores (n = 197) were significantly different only between dexamethasone (126 [79-149]) and dexmedetomidine (118.5 [41-150], P = 0.004), but by an amount less than the 8-point minimum clinically important difference.Dexamethasone is superior to dexmedetomidine as an intravenous adjunct for prolongation of bupivacaine-based ISB analgesic duration. There was no additional benefit to using both adjuncts in combination.www.clinicaltrials.gov (NCT03270033); registered 1 September 2017.RéSUMé: OBJECTIF: La dexaméthasone et la dexmédétomidine intraveineuses prolongent toutes deux la durée analgésique des blocs interscaléniques (BIS) après une chirurgie arthroscopique de l’épaule. Cette étude a comparé leur efficacité relative et les avantages d’une utilisation des deux agents en combinaison. MéTHODE: Cette étude de supériorité monocentrique en trois groupes parallèles à double insu a randomisé 198 patients adultes subissant une chirurgie arthroscopique de l’épaule en ambulatoire. Les patients ont reçu un BIS préopératoire composé de 30 mL de bupivacaïne 0,5 % avec 50 μg de dexmédétomidine, 4 mg de dexaméthasone, ou la combinaison de ces deux agents comme adjuvants intraveineux. Le critère d’évaluation principal était la durée analgésique du bloc. Les critères d’évaluation secondaires comprenaient le score de qualité de récupération (QoR) 15 (plage : 0-150) au jour 1 et les symptômes neurologiques postopératoires dans le bras opéré. RéSULTATS: Les durées des blocs (n = 195) avec la dexaméthasone (médiane [plage], 24,5 [2,0-339,5] heures) et la combinaison des deux adjuvants (24,0 [1,5-157,0] heures) ont été prolongées par rapport à la dexmédétomidine (16,0 [1,5-154,0] heures). Lorsqu’elles ont été analysées par régression linéaire après une transformation logarithmique non planifiée en raison de données biaisées vers la droite, les prolongations correspondantes de la durée du bloc étaient de 59 % (intervalle de confiance [IC] 95 %, 28 à 97) et de 46 % (IC 95 %, 18 à 80), respectivement (les deux P0,001). La combinaison des adjuvants n’était pas supérieure à la dexaméthasone seule (-8 %; IC 95 %, -26 à 14; P = 0,42). Les scores médians [ÉIQ] de qualité de récupération 15 (n = 197) n’étaient significativement différents qu’entre la dexaméthasone (126 [79-149]) et la dexmédétomidine (118,5 [41-150], P = 0,004), mais la différence observée était inférieure à la différence minimale de 8 points nécessaire pour être considérée cliniquement importante. CONCLUSION: La dexaméthasone est supérieure à la dexmédétomidine en tant qu’adjuvant intraveineux pour prolonger la durée analgésique d’un BIS à base de bupivacaïne. Aucun avantage supplémentaire n’a été observé lors de l’utilisation combinée des deux adjuvants. ENREGISTREMENT DE L’éTUDE: www.clinicaltrials.gov (NCT03270033); enregistrée le 1er septembre 2017.

Dexamethasone prolongs the duration of interscalene block, but the benefits of higher doses and perineural vs intravenous administration remain unclear. This factorial design, double-blinded trial randomized 280 adult patients undergoing ambulatory arthroscopic shoulder surgery at a single centre in a 1:1:1:1 ratio. Patients received ultrasound-guided interscalene block with 30 mL 0.5% bupivacaine and 4 mg or 8 mg dexamethasone by either the perineural or intravenous route. The primary outcome (block duration measured as the time of first pain at the surgical site) and secondary outcomes (adverse effects, postoperative neurologic symptoms) were assessed by telephone. In this superiority trial, the predetermined minimum clinically important difference for comparisons between doses and routes was 3.0 hr. The perineural route significantly prolonged the mean block duration by 2.0 hr (95% confidence interval [CI], 0.4 to 3.5 hr; P = 0.01), but 8 mg of dexamethasone did not significantly prolong the mean block duration compared with 4 mg (1.3 hr; 95% CI, −0.3 to 2.9 hr, P = 0.10), and there was no significant statistical interaction (P = 0.51). The mean (95% CI) block durations, in hours, were 24.0 (22.9 to 25.1), 24.8 (23.2 to 26.3), 25.4 (23.8 to 27.0), and 27.2 (25.2 to 29.3) for intravenous doses of 4 and 8 mg and perineural doses of 4 and 8 mg, respectively. There were no marked differences in side effects between groups. At 14 postoperative days, 57 (20.4%) patients reported neurologic symptoms, including dyspnea and hoarseness. At six months postoperatively, only six (2.1%) patients had residual symptoms, with four (1.4%) patients’ symptoms unlikely related to interscalene block. Compared with the intravenous route, perineural dexamethasone prolongs the mean interscalene block duration by a small amount that may or may not be clinically significant, regardless of dose. However, the difference in mean block durations between 8 mg and 4 mg of dexamethasone is highly unlikely to be clinically important, regardless of the administration route. www.clinicaltrials.gov (NCT02426736). Registered 14 April 2015.

Background: Myocardial injury after noncardiac surgery (MINS) was defined as prognostically relevant myocardial injury due to ischemia that occurs during or within 30 days after noncardiac surgery. The study’s four objectives were to determine the diagnostic criteria, characteristics, predictors, and 30-day outcomes of MINS. Methods: In this international, prospective cohort study of 15,065 patients aged 45 yr or older who underwent in-patient noncardiac surgery, troponin T was measured during the first 3 postoperative days. Patients with a troponin T level of 0.04 ng/ml or greater (elevated “abnormal” laboratory threshold) were assessed for ischemic features (i.e., ischemic symptoms and electrocardiography findings). Patients adjudicated as having a nonischemic troponin elevation (e.g., sepsis) were excluded. To establish diagnostic criteria for MINS, the authors used Cox regression analyses in which the dependent variable was 30-day mortality (260 deaths) and independent variables included preoperative variables, perioperative complications, and potential MINS diagnostic criteria. Results: An elevated troponin after noncardiac surgery, irrespective of the presence of an ischemic feature, independently predicted 30-day mortality. Therefore, the authors’ diagnostic criterion for MINS was a peak troponin T level of 0.03 ng/ml or greater judged due to myocardial ischemia. MINS was an independent predictor of 30-day mortality (adjusted hazard ratio, 3.87; 95% CI, 2.96–5.08) and had the highest population-attributable risk (34.0%, 95% CI, 26.6–41.5) of the perioperative complications. Twelve hundred patients (8.0%) suffered MINS, and 58.2% of these patients would not have fulfilled the universal definition of myocardial infarction. Only 15.8% of patients with MINS experienced an ischemic symptom. Conclusion: Among adults undergoing noncardiac surgery, MINS is common and associated with substantial mortality.

Cerebral desaturation occurs frequently in patients undergoing one-lung ventilation for thoracic surgery. The mechanism of this desaturation is unclear regarding its etiology. The objective of this study was to investigate whether or not decreases in cerebral oxygen saturation associated with one-lung ventilation were a consequence of decreased cardiac output. A blinded observational study was conducted in 23 patients undergoing one-lung ventilation with thoracic surgery. Eighteen patients completed the study. Cerebral oxygen saturation was monitored using near-infrared spectroscopy (FORE-SIGHT® monitor). Invasive blood pressure was monitored and hemodynamic variables were interrogated using the FloTrac® system. Anesthesia was maintained with sevoflurane with a F i O2 of 1.0. Post-hoc analysis involved a comparison between baseline and integrated changes in cerebral saturation, heart rate, stroke index, cardiac index, and stroke volume variability. All patients showed cerebral desaturation from a baseline of two-lung ventilation in the lateral decubitus position following institution of one-lung ventilation. The cardiac index was stable at these times, but with one-lung ventilation, the heart rate decreased and the stroke index increased to maintain a stable product. The integral of heart rate × time was inversely correlated with the integral of cerebral desaturation × time (linear regression analysis; P = 0.02; (df) = 16)). Cerebral oxygen desaturation was universal during one-lung ventilation in this study. There was no correlation between cerebral desaturation and cardiac output or other hemodynamic variables.

Intrathecal (IT) baclofen is an effective management strategy for controlling spasticity in patients unresponsive to maximal oral therapy. We present the case of a 57-yr-old woman who was rendered quadriplegic after a complete spinal cord transection at the C6 level. Her course was complicated by severe spasms, which were uncontrolled despite titrating orally administered baclofen to 80 mg/d. IT baclofen testing was performed with good response, and administration was commenced via an implanted intrathecal pump 6 mo after the injury at an initial dose of 200 microg/d. Catheter revision was required 2 wk later as a result of catheter displacement. The initial IT baclofen dose was gradually increased to achieve good control at a level of 400 microg/d. After a period of stability lasting 38 mo, her lower limb spasms dramatically increased in severity and remained poorly controlled despite repeated dose increases. Contrast pumpogram and computed tomography myelogram were performed to exclude a mechanical cause for this apparent increase in baclofen requirement. These investigations revealed neither catheter displacement nor fracture as suspected but, rather, displayed the presence of a catheter tip-associated mass. Catheter tip granuloma has not previously been described in a patient receiving IT baclofen alone. This suggests that although uncommon, the possibility of catheter-associated granuloma must be considered in all patients receiving IT baclofen presenting with altered neurological function or significant increase in drug requirement.

Purpose This study was designed to examine the efficacy of low-dose intrathecal morphine (ITM) on extubation times and pain control after cardiac surgery.

To the Editor, Chronic pain is recognized widely for its personal and societal burden, and it remains an elusive target for treatment success. While much has been learned about the pathophysiology, psychology, and medical therapeutics of pain, patients continue to languish awaiting entry into multidisciplinary pain clinics throughout Canada. Recent international publications have gone so far as to declare access to pain management as a fundamental right to be adhered to in the developed and developing world. Based on data collected from June 2005 to August 2006, Peng et al. surveyed access to Canadian Multidisciplinary Pain Clinics (MPC). Funding source (public or private) and province-of-service provision were independent predictors for MPC access times. With a solely publicly funded MPC, the wait time in Manitoba was the longest of the ten provinces. The Canadian Pain Society Wait Times Task Force Statement recommends wait times of no longer than six months for initial assessment at a MPC. Initiatives developed within the Pain Management Centre at the University of Manitoba allowed our MPC to reduce wait times to three months. The previous wait time for new referrals to enter our MPC averaged 33-months. Patients entered the MPC and were assessed as a ‘‘new consultation’’ by an anesthesiologist. The anesthesiologist would manage the patient’s treatment and consult with other practitioners. These practices ran in parallel, and anesthesiologists would cover for each other when their colleagues were not present in the clinic. After ‘‘follow-up consultation’’ for patients already within the clinic system, new patients were scheduled into the clinic as space allowed. A priority system allocated space to urgent pain categories first, including cancer pain, complex regional pain syndrome, and post-herpetic neuralgia. There was one physician clinic per day and one physician procedure clinic (fluoroscopic-guided procedures) per day. Nursing resources contributed to managing patients scheduled in clinics, with one nurse per day assigned to respond to telephone calls from patients (approximately 50-80 calls per day). Prior to restructuring, our clinic had approximately 5,000 active patients under care at any given time. We have increased our new patient visits from 550 to 1,050 per year (91% increase), and our follow-up visits have increased from 3,168 to 5,750 per year (82% increase). The two cornerstones of our practice restructuring are complete group practice, with each physician sharing responsibility for every patient, and a partnership with family physicians permitting patients to return to primary care when they have completed the patient navigation pathway. Patients enter the MPC and are assessed as a ‘‘new consultation’’ by an anesthesiologist who initiates a management course that includes medication titration, interventional management, and additional therapy with physical medicine, physiotherapy, and psychology. In order to standardize and facilitate timely methodical access to treatments, our clinic physicians have developed procedurebased algorithms that are tailored to individual patient needs. The current clinic infrastructure has added a second satellite site with a Pain Management Specialist present each day. At this second site we have added additional psychology, physiotherapy, and nursing resources. We are also adding a primary care physician to our model to assist in de-intensifying patients’ care as a step toward discharge back to their family physician. Our current and previous staff resources are reflected in the Table 1. R. J. Amadeo, MD (&) E. Sutherland, MD University of Manitoba, Winnipeg, Manitoba, Canada e-mail: ramadeo@shaw.ca