Joel L. Parlow

Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery

The Canadian Cardiovascular Society Guidelines Committee and key Canadian opinion leaders believed there was a need for up to date guidelines that used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system of evidence assessment for patients who undergo noncardiac surgery. Strong recommendations included: 1) measuring brain natriuretic peptide (BNP) or N-terminal fragment of proBNP (NT-proBNP) before surgery to enhance perioperative cardiac risk estimation in patients who are 65 years of age or older, are 45-64 years of age with significant cardiovascular disease, or have a Revised Cardiac Risk Index score ≥ 1; 2) against performing preoperative resting echocardiography, coronary computed tomography angiography, exercise or cardiopulmonary exercise testing, or pharmacological stress echocardiography or radionuclide imaging to enhance perioperative cardiac risk estimation; 3) against the initiation or continuation of acetylsalicylic acid for the prevention of perioperative cardiac events, except in patients with a recent coronary artery stent or who will undergo carotid endarterectomy; 4) against α2 agonist or β-blocker initiation within 24 hours before surgery; 5) withholding angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker starting 24 hours before surgery; 6) facilitating smoking cessation before surgery; 7) measuring daily troponin for 48 to 72 hours after surgery in patients with an elevated NT-proBNP/BNP measurement before surgery or if there is no NT-proBNP/BNP measurement before surgery, in those who have a Revised Cardiac Risk Index score ≥1, age 45-64 years with significant cardiovascular disease, or age 65 years or older; and 8) initiating of long-term acetylsalicylic acid and statin therapy in patients who suffer myocardial injury/infarction after surgery.

The effects of reversal of neuromuscular blockade on autonomic control in the perioperative period

Impaired parasympathetic control of heart rate is associated with increased incidence of cardiac dysrhythmias and ischemia.Anticholinergic drugs suppress parasympathetic control and could be detrimental in the early postoperative period in high-risk patients. In this double-blind randomized trial, 30 ASA physical status I and II patients undergoing minor surgery received either atropine 20 micro g/kg and neostigmine 50 micro g/kg (Group A), glycopyrrolate 8 micro g/kg and neostigmine 50 micro g/kg (Group G), or placebo (Group P) for reversal of neuromuscular blockade. Two indices of parasympathetic modulation of heart rate, spontaneous baroreflex sensitivity, and high-frequency heart rate variability, were assessed. At 2 h after reversal, Group A showed persisting impairment of baroreflex sensitivity with respect to Group P (7.12 +/- 0.86 vs 12.71 +/- 1.38 ms/mm Hg, P = 0.022) as well as decreased high-frequency heart rate variability (280.8 +/- 30.1 vs 569.2 +/- 115.2 ms2/Hz, P = 0.015). Groups A and G showed a borderline decrease in normalized high-frequency variability at 2 h (P = 0.05 for Groups A and G versus Group P). Anticholinergic drugs with neostigmine cause impairment of parasympathetic control of heart rate which persists into the early postoperative period. The effects of glycopyrrolate appear to be of shorter duration; this drug may thus be preferable in patients at risk of cardiovascular complications. (Anesth Analg 1997;84:148-54)

Post discharge nausea and vomiting after ambulatory laparoscopy is not reduced by promethazine prophylaxis

PurposeTo determine the incidence of post-discharge nausea and vomiting (PDNV) following outpatient laparoscopic procedures in women, and to assess the efficacy of the prophylactic administration of promethazine prior to discharge from hospital.MethodsNinety-five healthy women scheduled for ambulatory laparoscopic cholecystectomy or gynecological surgery completed this double blind, placebo controlled study. A standardized fentanyl-propofol-nitrous oxideisoflurane anesthetic was used, and all patients received 0.5 mg droperidoliv, intraoperatively. Subjects were randomized to receive 0.6 mg·kg−1 promethazine or placeboim prior to transfer from the post-anesthetic recovery (PAR) unit. The incidence and severity of nausea, pain, and drowsiness were documented using patient diaries at four time intervals during the first 24 hr postoperatively using four-point self-assessment scales.ResultsAfter discharge home, the overall incidence of nausea was 48%, moderate to severe nausea 30%, vomiting 17% and rescue antiemetic use 28%, with no difference between those receiving saline or promethazine. The need for antiemetics in the PAR was associated with subsequent PDNV with those requiring PAR antiemetics being four times as likely to vomit after discharge (P = 0.008).ConclusionDespite the prophylactic administration of 0.5 mg droperidoliv, patients undergoing ambulatory laparoscopic surgery reported a high incidence of nausea after discharge. Patients requiring antiemetics in the PAR were at higher risk for PDNV. The incidence of nausea was not altered by prophylactic administration of 0.6 mg·kg−1 promethazine im before discharge.RésuméObjectifDéterminer l’incidence de nausées et de vomissements postcongé (NVPC) après une laparoscopie ambulatoire et évaluer l’efficacité de l’administration prophylactique de prométhazine avant le départ de l’hôpital.MéthodeQuatre-vingt-dix femmes en santé, qui ont subi une cholécystectomie laparoscopique ou une intervention gynécologique, élective et ambulatoire, ont participé à une étude en double aveugle contre placebo. L’anesthésie était standard: fentanyl, propofol, protoxyde d’azote et isoflurane. Toutes les patientes ont reçu 0,5 mg de dropéridoliv peropératoire. Elles ont été réparties de façon aléatoire et ont reçu, soit 0,6 mg·kg−1 de prométhazine, soit un placeboim avant le transfert de la salle de réveil. L’incidence et la sévérité des nausées et des vomissements, de la douleur et de la somnolence ont été documentées en utilisant ce que les patientes ont noté à quatre reprises pendant les premières 24h postopératoires selon des échelles d’évaluation personnelle en quatre points.RésultatsAprès le congé, l’incidence globale de nausées a été de 48%; de nausées modérées ou sévères, 30%; de vomissements, 17% et de recours aux antiémétiques, 28%, sans différence intergroupe (placebovs prométhazine). La demande d’antiémétiques à la salle de réveil était associée aux NVPC subséquents, les patientes qui ont reçu ces antiémétiques étant quatre fois plus à risque de vomir après le départ de l’hôpital (P = 0,008).ConclusionMalgré l’administration prophylactique de 0,5 mg de dropéridoliv, les patientes qui subissent une opération laparoscopique ambulatoire ont rapporté une forte incidence de nausées après le congé de l’hôpital. Celles qui ont eu besoin d’antiémétiques à la salle de réveil étaient plus à risque de NVPC. L’incidence des nausées n’a pas été modifiée par l’administration prophylactique de 0,6 mg·kg−1 de prométhazineim avant le départ.

In Canada, anesthesiologists are less likely to respond to an electronic, compared to a paper questionnaire

PurposeA randomized unblinded controlled trial was used to assess the utility of electronic questionnaires in a survey of Canadian anesthesiologists.MethodsPostal or electronic questionnaires were sent between November 2001 and March 2002 to 1,333 anesthesiologists registered with the Canadian Anesthesiologists’ Society. The primary outcome measure was the difference in response rates between electronic and postal questionnaires. Secondary outcome measures included a comparison of demographic characteristics, cost, and knowledge and practice regarding prophylactic perioperative beta blockade.ResultsThe overall response rate was 52%. E-mail participants were half as likely as postal participants to respond to the questionnaire (35% vs 69%, relative risk = 0.51, 95% confidence interval 0.45–0.58). Respondents who provided an e-mail address were younger and more likely to be affiliated with an academic institution. There were no significant differences in responses to knowledge and practice questions. The electronic arm was faster than the postal arm and the cost per reply was one-third the cost of the postal arm (

Addition of opioids alters the density and spread of intrathecal local anesthetics? An in vitro study.

2.50 vs

Perioperative Aspirin and Clonidine and Risk of Acute Kidney Injury A Randomized Clinical Trial

8.02).ConclusionsElectronic surveys are a means of acquiring information from a large number of individuals in a rapid, efficient and cost-effective manner. This methodology may be particularly valid and useful in surveys of participants with similar backgrounds and internet access. However the lower response rates achieved as compared with postal surveys indicates a need to use vigilance when generalizing results to a broader population.RésuméObjectifNous avons utilisé une épreuve randomisée, contrôlée et ouverte pour évaluer l’utilité de questionnaires électroniques lors d’une enquête auprès des anesthésiologistes canadiens.MéthodeDes questionnaires postaux et électroniques ont été envoyés entre novembre 2001 et mars 2002 à 1 333 anesthésiologistes membres de la Société canadienne des anesthésiologistes. La principale mesure a été la différence du taux de réponses aux envois postaux et électroniques. La seconde comprenait une comparaison des caractéristiques individuelles, du coût, et des connaissances et de la pratique en regard du bêta blocage périopératoire préventif.RésultatsLe taux de réponse général a été de 52 %. Les participants par courriel ont été deux fois moins nombreux que par la poste à répondre au questionnaire (35 % vs 69%, le risque relatif a été de 0,51, l’intervalle de confiance de 95 % 0,45–0,58). Les répondants par courriel étaient plus jeunes et plus souvent affiliés à une institution universitaire. Il n’y a pas eu de différence significative de réponses sur les connaissances et la pratique. Le groupe du courriel a répondu plus rapidement que le groupe de la poste et le coût par réponse a été le tiers du coût postal (2,50

Effects of Endotracheal Tube Suctioning on Arterial Oxygen Tension and Heart Rate Variability

vs 8,02

Hypoxic Pulmonary Vasoconstriction: From Molecular Mechanisms to Medicine

).ConclusionLes enquêtes électroniques permettent d’obtenir de l’information d’un grand nombre de personnes d’une manière rapide, efficace et économique. Cette méthodologie peut être particulièrement valide et utile auprès de participants dont les connaissances sont comparables et qui ont accès à Internet. Cependant, les taux de réponses plus bas obtenus en comparaison avec les enquêtes postales indiquent la nécessité d’être vigilant au moment de généraliser les résultats pour une importante population.

The effects of exercise conditioning in normal and overweight pregnant women on blood pressure and heart rate variability.

PurposeTo determine whether the addition of opioids alters the density and spread of intrathecal local anestheticsin vitro.MethodsIn Part I, the densities of hyperbaric bupivacaine 0.75% (HB), hyperbaric lidocaine 5% (HL) and isobaric bupivacaine 0.5% (IB) with and without morphine (M), and fentanyl (F) were measured at 22°C. In Part II a model was constructed utilizing a column containing a solution similar in composition to cerebrospinal fluid (CSF) at 37°C. The various local anesthetic-opioid solutions, coloured with crystalline méthylène blue dye, were injected at 22°C into the column at a controlled rate through a spinal needle. The direction and extent of spread of the injectâtes were compared.ResultsThe relative densities of the five solutions were: HB = HL > IB > M > F The addition of fentanyl to IB reduced the density of the final solution (P < 0.05). In the model, IB alone and IB with morphine showed mainly downward spread, with the addition of fentanyl to IB resulting in upward movement (P = 0.004). The hyperbaric local anesthetics moved downward with or without opioids.ConclusionThe addition of fentanyl reduces the density of IBin vitro and alters its movement in simulated CSF. This may prove to be important in predicting the level of spinal block in clinical practice.RésuméObjectifDéterminer si l’addition d’opioïdes a un effet sur la densité et l’étalement des anesthésiques locaux intrathécaux, utilisésin vitro.MéthodeDans la Partie I, les densités de la bupivacaïne hyperbare 0,75 % (BH), de la lidocaine hyperbare 5 % (LH) et de la bupivacaïne isobare 0,5 % (B1) accompagnées ou non de morphine (M) et de fentanyl (F) ont été mesurées à 22 °C. Dans la Partie II, on a construit un modèle qui utilise une colonne contenant une solution dont la composition est similaire à celle du liquide céphalorachidien (LCR) à 37 °C. Les différentes solutions d’opioïdes-anesthésiques locaux, colorées avec du bleu de méthylène cristallin, ont été injectées à 22 °C dans la colonne à un débit contrôlé et au moyen d’une aiguille rachidienne. La direction et l’étendue de l’infiltration des solutions injectées ont été comparées.RésultatsLes densités relatives des cinq solutions ont été : BH = LH > Bl > M > F L’ajout de fentanyl à la B1 a réduit la densité de la solution finale (P < 0,05). Dans le modèle, la B1 employée seule et la Bl avec la morphine se sont étendues principalement vers le bas, mais la Bl avec du fentanyl s’est propagée vers le haut (P = 0,004). Les anesthésiques locaux hyperbares s’étendent vers le bas, qu’ils soient avec ou sans opioïdes.ConclusionLajout de fentanyl réduit la densité de la Blin vitro et change son mouvement dans le LCR artificiel. Cette donnée peut se révéler importante pour prévoir le niveau de blocage rachidien en pratique clinique.

The relationship between movement-evoked versus spontaneous pain and peak expiratory flow after abdominal hysterectomy

IMPORTANCE Acute kidney injury, a common complication of surgery, is associated with poor outcomes and high health care costs. Some studies suggest aspirin or clonidine administered during the perioperative period reduces the risk of acute kidney injury; however, these effects are uncertain and each intervention has the potential for harm. OBJECTIVE To determine whether aspirin compared with placebo, and clonidine compared with placebo, alters the risk of perioperative acute kidney injury. DESIGN, SETTING, AND PARTICIPANTS A 2 × 2 factorial randomized, blinded, clinical trial of 6905 patients undergoing noncardiac surgery from 88 centers in 22 countries with consecutive patients enrolled between January 2011 and December 2013. INTERVENTIONS Patients were assigned to take aspirin (200 mg) or placebo 2 to 4 hours before surgery and then aspirin (100 mg) or placebo daily up to 30 days after surgery, and were assigned to take oral clonidine (0.2 mg) or placebo 2 to 4 hours before surgery, and then a transdermal clonidine patch (which provided clonidine at 0.2 mg/d) or placebo patch that remained until 72 hours after surgery. MAIN OUTCOMES AND MEASURES Acute kidney injury was primarily defined as an increase in serum creatinine concentration from the preoperative concentration by either an increase of 0.3 mg/dL or greater (≥26.5 μmol/L) within 48 hours of surgery or an increase of 50% or greater within 7 days of surgery. RESULTS Aspirin (n = 3443) vs placebo (n = 3462) did not alter the risk of acute kidney injury (13.4% vs 12.3%, respectively; adjusted relative risk, 1.10; 95% CI, 0.96-1.25). Clonidine (n = 3453) vs placebo (n = 3452) did not alter the risk of acute kidney injury (13.0% vs 12.7%, respectively; adjusted relative risk, 1.03; 95% CI, 0.90-1.18). Aspirin increased the risk of major bleeding. In a post hoc analysis, major bleeding was associated with a greater risk of subsequent acute kidney injury (23.3% when bleeding was present vs 12.3% when bleeding was absent; adjusted hazard ratio, 2.20; 95% CI, 1.72-2.83). Similarly, clonidine increased the risk of clinically important hypotension. In a post hoc analysis, clinically important hypotension was associated with a greater risk of subsequent acute kidney injury (14.3% when hypotension was present vs 11.8% when hypotension was absent; adjusted hazard ratio, 1.34; 95% CI, 1.14-1.58). CONCLUSIONS AND RELEVANCE Among patients undergoing major noncardiac surgery, neither aspirin nor clonidine administered perioperatively reduced the risk of acute kidney injury. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01082874.