Basem Abdelmalak

Analysis of risk factors for myocardial infarction and cardiac mortality after major vascular surgery

Background Patients undergoing vascular surgical procedures are at high risk for perioperative myocardial infarction (PMI). This study was undertaken to identify predictors of PMI and in-hospital death in major vascular surgical patients. Methods From the Vascular Surgery Registry (6,948 operations from January 1989 through June 1997) the authors identified 107 patients in whom PMI developed during the same hospital stay. Case–control patients (patients without PMI) were matched at a 1×:×1 ratio with index cases according to the type of surgery, gender, patient age, and year of surgery. The authors analyzed data regarding preoperative cardiac disease and surgical and anesthetic factors to study association with PMI and cardiac death. Results By using univariable analysis the authors identified the following predictors of PMI: valvular disease (P = 0.007), previous congestive heart failure (P = 0.04), emergency surgery (P = 0.02), general anesthesia (P = 0.03), preoperative history of coronary artery disease (P = 0.001), preoperative treatment with &bgr;-blockers (P = 0.003), lower preoperative (P = 0.03) and postoperative (P = 0.002) hemoglobin concentrations, increased bleeding rate (as assessed from increased cell salvage;P = 0.025), and lower ejection fraction (P = 0.02). Of the 107 patients with PMI, 20.6% died of cardiac cause during the same hospital stay. The following factors increased the odds ratios for cardiac death: age (P = 0.001), recent congestive heart failure (P = 0.01), type of surgery (P = 0.04), emergency surgery (P = 0.02), lower intraoperative diastolic blood pressure (P = 0.001), new intraoperative ST-T changes (P = 0.01), and increased intraoperative use of blood (P = 0.005). Patients who underwent coronary artery bypass grafting, even more than 12 months before index surgery, had a 79% reduction in risk of death if they had PMI (P = 0.01). Multivariable analysis revealed preoperative definitive diagnosis of coronary artery disease (P = 0.001) and significant valvular disease (P = 0.03) were associated with increased risk of PMI. Congestive heart failure less than 1 yr before index vascular surgery (P = 0.0002) and increased intraoperative use of blood (P = 0.007) were associated with cardiac death. The history of coronary artery bypass grafting reduced the risk of cardiac death (P = 0.04) in patients with PMI. Conclusions The in-hospital cardiac mortality rate is high for patients who undergo vascular surgery and experience clinically significant PMI. Stress of surgery (increased intraoperative bleeding and aortic, peripheral vascular, and emergency surgery), poor preoperative cardiac functional status (congestive heart failure, lower ejection fraction, diagnosis of coronary artery disease), and preoperative history of coronary artery bypass grafting are the factors that determine perioperative cardiac morbidity and mortality rates.

Neurological biomarkers in the perioperative period

The rapid detection and evaluation of patients presenting with perioperative neurological dysfunction is of great clinical relevance. Biomarkers have been defined as biological molecules that can be used as an indicator of new onset or progression of a biological process or effect of treatment. Biomarkers have become increasingly important in this setting to supplement other modalities of diagnosis such as EEG, sensory- or motor-evoked potential, transcranial Doppler, near-infrared spectroscopy, or imaging methods. A number of neuro-proteins have been identified and are currently under investigation for potential to provide insights into injury severity, outcome, and the ability to monitor cellular damage and molecular events that occur during neurological injury. S100B is a protein released by glial cells and is considered a marker of blood-brain barrier dysfunction. Clinical studies in patients undergoing cardiac and non-cardiac surgery indicate that serum levels of S100B are increased intraoperatively and after operation. The neurone-specific enolase has also been extensively investigated as a potential marker of neuronal injury in the context of cardiac and non-cardiac surgery. A third biomarker of interest is the Tau protein, which has been linked to neurodegenerative disorders. Tau appears to be more specific than the previous two biomarkers since it is only found in the central nervous system. The metalloproteinase and ubiquitin C terminal hydroxylase-L1 (UCH-L1) are the most recently researched markers; however, their usefulness is still unclear. This review presents a comprehensive overview of S100B, neuronal-specific enolase, metalloproteinases, and UCH-L1 in the perioperative period.

The hyperglycemic response to major noncardiac surgery and the added effect of steroid administration in patients with and without diabetes.

BACKGROUND:The pattern and magnitude of the hyperglycemic response to surgical stress, the added effect of low-dose steroids, and whether these differ in diabetics and nondiabetics remain unclear. We therefore tested 2 hypotheses: (1) that diabetics show a greater increase from preoperative to intraoperative glucose concentrations than nondiabetics; and (2) that steroid administration increases intraoperative hyperglycemia more so in diabetics compared with nondiabetics. METHODS:Patients scheduled for major noncardiac surgery under general anesthesia were enrolled and randomized to preoperative IV 8 mg dexamethasone or placebo, stratified by diagnosis of diabetes. Patients were part of a larger underlying trial (the Dexamethasone, Light Anesthesia and Tight Glucose Control [DeLiT] Trial). IV insulin was given when glucose concentration exceeded 215 mg/dL. The primary outcome measure was the change in glucose from the preoperative to maximal intraoperative glucose concentration. We also report the time-dependent pattern of intraoperative hyperglycemia. RESULTS:Ninety patients (23% with diabetes) were randomized to dexamethasone, and 95 (29% with diabetes) were given placebo. The mean ± SD change from preoperative to maximal intraoperative glucose concentration was 63 ± 69 mg/dL in diabetics and 72 ± 45 mg/dL in nondiabetics. The mean covariable-adjusted change (95% confidence interval) in nondiabetics was 29 (13, 46) mg/dL more than in diabetics (P < 0.001). For all patients combined, mean glucose increased slightly from preoperative to incision, substantially from incision to surgery midpoint, and then remained high and fairly stable through emergence, with nondiabetic patients showing a greater increase (P < 0.001). For nondiabetics, the mean increase in glucose concentration (97.5% CI) was 29 (9, 49) mg/dL more in patients given dexamethasone than placebo (P = 0.0012). However, there was no dexamethasone effect in diabetics (P = 0.99). CONCLUSIONS:Treatment of intraoperative hyperglycemia should account for the hyperglycemic surgical stress response trend depending on the stage of surgery as well as the added effects of steroid administration. Denying steroid prophylaxis for postoperative nausea and vomiting for fear of hyperglycemic response should be reconsidered given the limited effect of steroids on intraoperative blood glucose concentrations.

Dexamethasone, light anaesthesia, and tight glucose control (DeLiT) randomized controlled trial

BACKGROUND The inflammatory response to surgical tissue injury is associated with perioperative morbidity and mortality. We tested the primary hypotheses that major perioperative morbidity is reduced by three potential anti-inflammatory interventions: (i) low-dose dexamethasone, (ii) intensive intraoperative glucose control, and (iii) lighter anaesthesia. METHODS We enrolled patients having major non-cardiac surgery who were ≥40 yr old and had an ASA physical status ≤IV. In a three-way factorial design, patients were randomized to perioperative i.v. dexamethasone (a total of 14 mg tapered over 3 days) vs placebo, intensive vs conventional glucose control 80-110 vs 180-200 mg dl(-1), and lighter vs deeper anaesthesia (bispectral index target of 55 vs 35). The primary outcome was a collapsed composite of 15 major complications and 30 day mortality. Plasma high-sensitivity (hs) C-reactive protein (CRP) concentration was measured before operation and on the first and second postoperative days. RESULTS The overall incidence of the primary outcome was about 20%. The trial was stopped after the second interim analysis with 381 patients, at which all three interventions crossed the futility boundary for the primary outcome. No three-way (P=0.70) or two-way (all P>0.52) interactions among the interventions were found. There was a significantly smaller increase in hsCRP in patients given dexamethasone than placebo [maximum 108 (64) vs 155 (69) mg litre(-1), P<0.001], but none of the other two interventions differentially influenced the hsCRP response to surgery. CONCLUSIONS Among our three interventions, dexamethasone alone reduced inflammation. However, no intervention reduced the risk of major morbidity or 1 yr mortality. TRIAL REGISTRATION IDENTIFIER: NCT00433251 at www.clinicaltrials.gov.

Design and Organization of the Dexamethasone, Light Anesthesia and Tight Glucose Control (DeLiT) Trial: a factorial trial evaluating the effects of corticosteroids, glucose control, and depth-of-anesthesia on perioperative inflammation and morbidity from major non-cardiac surgery

BackgroundThe perioperative period is characterized by an intense inflammatory response. Perioperative inflammation promotes postoperative morbidity and increases mortality. Blunting the inflammatory response to surgical trauma might thus improve perioperative outcomes. We are studying three interventions that potentially modulate perioperative inflammation: corticosteroids, tight glucose control, and light anesthesia.Methods/DesignThe DeLiT Trial is a factorial randomized single-center trial of dexamethasone vs placebo, intraoperative tight vs. conventional glucose control, and light vs deep anesthesia in patients undergoing major non-cardiac surgery. Anesthetic depth will be estimated with Bispectral Index (BIS) monitoring (Aspect medical, Newton, MA). The primary outcome is a composite of major postoperative morbidity including myocardial infarction, stroke, sepsis, and 30-day mortality. C-reactive protein, a measure of the inflammatory response, will be evaluated as a secondary outcome. One-year all-cause mortality as well as post-operative delirium will be additional secondary outcomes. We will enroll up to 970 patients which will provide 90% power to detect a 40% reduction in the primary outcome, including interim analyses for efficacy and futility at 25%, 50% and 75% enrollment.DiscussionThe DeLiT trial started in February 2007. We expect to reach our second interim analysis point in 2010. This large randomized controlled trial will provide a reliable assessment of the effects of corticosteroids, glucose control, and depth-of-anesthesia on perioperative inflammation and morbidity from major non-cardiac surgery. The factorial design will enable us to simultaneously study the effects of the three interventions in the same population, both individually and in different combinations. Such a design is an economically efficient way to study the three interventions in one clinical trial vs three.Trial registrationThis trial is registered at Clinicaltrials.gov #: NTC00433251

Revisiting tight glycemic control in perioperative and critically ill patients: when one size may not fit all ☆ ☆☆

Glycemic control has received intense scrutiny in the last decade as an important aspect of patient care. Earlier studies suggested that tight glycemic control (target level of 80 - 110 mg/dL) improved outcomes in intensive care unit (ICU) patients. Subsequent trials did not confirm the same benefit. Moreover, increased mortality was found in association with such tight control compared with a less strict target. As a result, tight glucose control has become less popular. The interaction between diabetic status and outcomes in relation to glucose control strategies and/or chronic glycemic state in perioperative and critically ill patients was examined. Tight glucose control appears to be more beneficial in patients without diabetes than in those with known diabetes. It also may be more beneficial in improving outcomes in surgical rather than nonsurgical ICU patients, and in decreasing sepsis rather than mortality. Tight glycemic control was associated with a high incidence of hypoglycemia, which may offset some of its potential benefits. Tight glycemic control in the perioperative and intensive care settings should not be totally abandoned either as a clinical practice or as a subject of future research. Beneficial effects of tight glycemic control may be demonstrated when the appropriate glycemic targets are matched to the appropriate population.

Vasovagal cardiac arrest during the insertion of an epidural catheter and before the administration of epidural medication.

C ardiac arrest during epidural anesthesia has been attributed to local anesthetic and opioid overdose (l), intravascular injection of local anesthetic (2), sympathetic blockade especially in the presence of hypovolemia, excessive sedation in the presence of hypoxemia (3), hypercarbia (4), or autonomic imbalance during recovery from neuraxial blockade (5). Cardiac arrest due to psychogenic causes during extensive sympathetic blockade (6) or during establishment of spinal anesthesia (7) has rarely been described. In both reports, the patients had already received local anesthesia. In the first case (6), the patient experienced vasovagal asystole after the surgeon informed him about the poor prognosis of his vascular surgery. In the second patient (7), a presumed vasovagal arrest occurred immediately after the administration of local anesthetic. We report a patient who experienced cardiac arrest due to a vasovagal syncope that occurred during insertion of an epidural catheter and before any medication was administered epidurally.

Perioperative glycemic management in insulin pump patients undergoing noncardiac surgery.

Increasingly more Americans are being diagnosed with diabetes mellitus, and the number of those using the continuous subcutaneous insulin infusion pump (CSII), commonly known as the insulin pump, is on the rise. Although evidence is lacking on how best to manage insulin pump patients perioperatively, several individual or institutional approaches have been developed. Here we propose a comprehensive algorithm for perioperative glycemic management in insulin pump patients undergoing noncardiac surgery. Where applicable, we discuss the rationale behind the algorithm.

Anesthesia for otolaryngologic surgery

Anesthesia for otolaryngologic surgery / , Anesthesia for otolaryngologic surgery / , کتابخانه دیجیتال جندی شاپور اهواز

Dexmedetomidine supplemented with local anesthesia for awake laryngoplasty

Certain laryngeal procedures require a sedated patient who is responsive to allow for the assessment of vocalization. Dexmedetomidine as a single agent for sedation and anxiolysis for awake laryngoplasty in a patient with unilateral vocal fold paralysis is presented.