Showing papers in "Canadian Journal of Anaesthesia-journal Canadien D Anesthesie in 2010"

A systematic review of screening questionnaires for obstructive sleep apnea.

Abstract: Obstructive sleep apnea (OSA) may lead to life-threatening problems if it is left undiagnosed. Polysomnography is the “gold standard” for OSA diagnosis; however, it is expensive and not widely available. The objective of this systematic review is to identify and evaluate the available questionnaires for screening OSA. We carried out a literature search through MEDLINE, EMBASE, and CINAHL to identify eligible studies. The methodological validity of each study was assessed using the Cochrane Methods Group’s guideline. Ten studies (n = 1,484 patients) met the inclusion criteria. The Berlin questionnaire was the most common questionnaire (four studies) followed by the Wisconsin sleep questionnaire (two studies). Four studies were conducted exclusively on “sleep-disorder patients”, and six studies were conducted on “patients without history of sleep disorders”. For the first group, pooled sensitivity was 72.0% (95% confidence interval [CI]: 66.0-78.0%; I2 = 23.0%) and pooled specificity was 61.0% (95% CI: 55.0-67.0%; I2 = 43.8%). For the second group, pooled sensitivity was 77.0% (95% CI: 73.0-80.0%; I2 = 78.1%) and pooled specificity was 53.0% (95% CI: 50-57%; I2 = 88.8%). The risk of verification bias could not be eliminated in eight studies due to insufficient reporting. Studies on snoring, tiredness, observed apnea, and high blood pressure (STOP) and STOP including body mass index, age, neck circumference, gender (Bang) questionnaires had the highest methodological quality. The existing evidence regarding the accuracy of OSA questionnaires is associated with promising but inconsistent results. This inconsistency could be due to studies with heterogeneous design (population, questionnaire type, validity). STOP and STOP-Bang questionnaires for screening of OSA in the surgical population are suggested due to their higher methodological quality and easy-to-use features.

International Standards for a Safe Practice of Anesthesia 2010

Abstract: These standards1 are recommended for anesthesia professionals throughout the world. They are intended to provide guidance and assistance to anesthesia professionals, their professional societies, hospital and facility administrators, and governments for improving and maintaining the quality and safety of anesthesia care. They were adopted by the World Federation of Societies of Anaesthesiologists on the 13th June 1992, and revisions were ratified on 5th March 2008 and on 19th March 2010. For some anesthesia services, groups, and departments these standards will represent a future goal, while for others they may already have been implemented and be regarded as mandatory. It is recognized that in some settings facing challenges in resources and organization, not even those standards regarded as mandatory are met at present. The provision of anesthesia under such circumstances should be restricted to procedures which are absolutely essential for the urgent or emergency saving of life or limb, and every effort should be made by those responsible for the provision of healthcare in these areas and settings to ensure that the standards are met. Provision of anesthesia care at standards lower than those outlined as mandatory for anesthesia for elective surgical procedures simply cannot be construed as safe acceptable practice. The most important standards relate to individual anesthesia professionals. Monitoring devices play an important part in safe anesthesia as extensions of human senses and clinical skills rather than their replacement. Adopting the standardized language of the World Health Organization, minimum standards that would be expected in all anesthesia care for elective surgical procedures are termed “HIGHLY RECOMMENDED” and these are the functional equivalent of “mandatory” standards. These HIGHLY RECOMMENDED standards, indicated in bold type, are applicable throughout any elective procedure, from patient evaluation until recovery (it is recognized, however, that immediate life-saving measures always take precedence in an emergency). In the judgement of the WFSA, these are the minimum standards for anesthesia for a “necessary” procedure (rather than essential and/or emergency) in settings where resources are extremely limited. This does not imply that these standards on their own are ideal or even acceptable in more adequately resourced settings. These HIGHLY RECOMMENDED (functional equivalent of mandatory) standards and (regarding facilities, equipment, and medications) the parallel prescription for “Level 1” or “basic” infrastructure are relevant to any healthcare environment anywhere in which general or regional anesthetics are administered, but not to a setting where superficial procedures involving local anesthetics only are performed. Additional elements of the anesthesia standards should be implemented as resources, organization, and training permit, yielding this paradigm: See Table 1 for a detailed outline of the integration of the practice standards with the levels of facilities/infrastructure. The goal always in any setting is to practice to the highest possible standards, specifically exceeding those prescribed if that can be accomplished. In spite of some facilities’ limitations, it may be possible to implement elements of the RECOMMENDED standards even in a “basic” setting and, likewise, to implement elements of the Suggested standards even in an “intermediate” setting. The goal is always the best care possible and ongoing improvement by meeting and exceeding the standards for safe practice of anesthesia, starting with all providers meeting the HIGHLY RECOMMENDED standards and striving to meet as many of the RECOMMENDED and Suggested standards as well. Table 1 Guide to Infrastructure, Supplies and Anesthesia Standards at Three Levels of Health Care Facility Infrastructure and Supplies It is anticipated that these standards and the setting/infrastructure specifications will be revised as practice and technology evolve.

Treatment of complex regional pain syndrome: a review of the evidence

Abstract: Purpose This narrative review summarizes the evidence derived from randomized controlled trials pertaining to the treatment of complex regional pain syndrome (CRPS).

Epidural anesthesia and cancer recurrence rates after radical prostatectomy

Abstract: Purpose To determine the effect of adjunctive epidural local anesthetic and opioid infusion on disease recurrence following radical prostatectomy for adenocarcinoma under general anesthesia.

Emergence agitation in adults: risk factors in 2,000 patients.

Abstract: The study was designed to determine the incidence of postoperative agitation following general anesthesia in 2,000 adult patients and to examine the associated risk factors. The study enrolled 2,000 adults who were scheduled for surgery under general anesthesia in a single institution during December 2007 to December 2008. The following risk factors were examined: age, gender, ASA physical status, type of surgery, anesthesia technique (inhalational or intravenous), administration of neostigmine or doxapram, adequate postoperative analgesia, pain, presence of a tracheal tube, and presence of a urinary catheter. Agitation occurred in 426 patients (21.3%). It was more common in males (28.1%) than in females (16.1%) (P = 0.017) and more prevalent after inhalational (27.8%) than total intravenous (7.5%) anesthesia (P = 0.001). Agitation was more common after oral cavity and otolaryngological surgery than after other types of surgery. Multivariate analysis showed that use of doxapram (odds ratio [OR] = 9.2; 95% confidence interval [CI] = 6.2 - 15.4; P = 0.002) and pain (OR = 8.2; 95% CI = 4.5 - 16.9; P < 0.001) were the most important risk factors associated with emergence agitation. Other causes were the presence of a tracheal tube and/or a urinary catheter. Adequate postoperative analgesia was associated with less agitation (OR = 0.4; 95% CI = 0.1 - 0.4; P = 0.006). Doxapram administration, pain, and presence of a tracheal tube and/or a urinary catheter appear to be the most important causes of postoperative agitation. To avoid this complication, it is suggested, whenever possible, to use intravenous anesthesia, to remove endotracheal tubes and urinary catheters as early as possible, and to provide adequate postoperative analgesia.

The Canadian STOP-PAIN project – Part 1: Who are the patients on the waitlists of multidisciplinary pain treatment facilities?

Abstract: The Canadian STOP-PAIN Project assessed the human and economic burden of chronic pain in individuals on waitlists of Multidisciplinary Pain Treatment Facilities (MPTF) This article presents the patients’ bio-psycho-social profile A sample of 728 patients was recruited from waitlists of eight university-affiliated MPTFs across Canada Subjects completed validated questionnaires to: 1) assess the characteristics and impact of their pain; and 2) evaluate their emotional functioning and quality of life (QoL) Follow-up questionnaires were completed by a subgroup of 271 patients three months later Close to 2/3 of the participants reported severe pain (≥ 7/10) that interfered substantially with various aspects of their daily living and QoL Severe or extremely severe levels of depression were common (500%) along with suicidal ideation (346%) Patients aged > 60 yr were twice as likely to experience severe pain (≥ 7/10) as their younger counterparts (P = 0002) Patients with frequent sleep problems were more at risk of reporting severe pain (P ≤ 0003) Intense pain was also associated with a greater tendency to catastrophize (P < 00001) severe depressive symptoms (P = 0003) and higher anger levels (P = 0016) Small but statistically significant changes in pain intensity and emotional distress were observed over a three-month wait time (all P < 005) This study highlights the severe impairment that patients experience waiting for treatment in MPTFs Knowing that current facilities cannot meet the clinical demand, it is clear that effective prevention/treatment strategies are needed earlier in primary and secondary care settings to minimize suffering and chronicity

Local anesthetic systemic toxicity

Abstract: The practice of regional anesthesia has been revitalized of late with the popularization of ultrasound-guided techniques. Advocates must be vigilant for the effects of unintentionally high blood levels of local anesthetic. Systemic local anesthetic toxicity, though rare, is a potentially devastating occurrence. This narrative review summarizes the effects of local anesthetic toxicity. We highlight how these toxic effects have motivated the search for a safe and long-acting local anesthetic. We outline current prevention and treatment options and appraise an emerging therapy in light of unfolding evidence. A search of the English language literature was conducted using the PubMed database from the National Library of Medicine. Bibliographies of retrieved articles were used to retrieve additional articles. The advent of multiple safety steps has led to a dramatic reduction in the incidence of local anesthetic toxicity over the past 30 years. Rising plasma levels of local anesthetic lead to a progressive spectrum of neurological and cardiac effects. Seizure activity may herald the onset of myocardial depression and ventricular arrhythmias that are often refractory to treatment. In addition to specific measures, such as lipid emulsion therapy, general supportive measures are warranted, for example, Advanced Life Support Guidelines. Vigilance during the performance of regional anesthesia and immediate intervention at the earliest sign of toxicity improve the chances of successful treatment.

Management of sleep apnea in adults - functional algorithms for the perioperative period: Continuing Professional Development

Abstract: Purpose Obstructive sleep apnea (OSA) is defined by repetitive partial or complete upper airway obstruction characterized by episodes of breathing cessation during sleep. It is the most prevalent of sleep disorders, seen in about one in four males and one in ten females. We reviewed current literature, collated expert opinion, and synthesized protocols from several institutions to present practical principles and functional algorithms to assist the anesthesiologist in the perioperative management of known and suspected OSA.

Extracorporeal lung support for patients who had severe respiratory failure secondary to influenza A (H1N1) 2009 infection in Canada

Abstract: From March to July 2009, influenza A (H1N1) 2009 (H1N1-2009) virus emerged as a major cause of respiratory failure that required mechanical ventilation. A small proportion of patients who had this condition developed severe respiratory failure that was unresponsive to conventional therapeutic interventions. In this report, we describe characteristics, treatment, and outcomes of critically ill patients in Canada who had H1N1-2009 infection and were treated with extracorporeal lung support (ECLS). We report the findings of a case series of six patients supported with ECLS who were included in a cohort study of critically ill patients with confirmed H1N1-2009 infection. The patients were treated in Canadian adult and pediatric intensive care units (ICUs) from April 16, 2009 to August 12, 2009. We describe the nested sample treated with ECLS and compare it with the larger sample. During the study period, 168 patients in Canada were admitted to ICUs for severe respiratory failure due to confirmed H1N1-2009 infection. Due to profound hypoxemia unresponsive to conventional therapeutic interventions, six (3.6%) of these patients were treated with ECLS in four ICUs. Four patients were treated with veno-venous pump-driven extracorporeal membrane oxygenation (vv-ECMO), and two patients were treated with pumpless lung assist (NovaLung iLA). The mean duration of support was 15 days. Four of the six patients survived (66.6%), one of the surviving patients was supported with iLA and the other three surviving patients were supported with ECMO. The two deaths were due to multiorgan failure, which occurred while the patients were on ECLS. Extracorporeal lung support may be an effective treatment for patients who have H1N1-2009 infection and refractory hypoxemia. Survival of these patients treated with ECLS is similar to that reported for patients who have acute respiratory distress syndrome of other etiologies and are treated with ECMO.

Preload or coload for spinal anesthesia for elective Cesarean delivery: a meta-analysis.

Abstract: Hypotension following spinal anesthesia for Cesarean delivery is common. Fluid loading is recommended to prevent hypotension, but preload is often ineffective. In non-pregnant patients, coloading has been shown to better maintain cardiac output after spinal anesthesia. The purpose of this meta-analysis was to determine whether the timing of the fluid infusion, before (preload) or during (coload) induction of spinal anesthesia for Cesarean delivery, influences the incidence of maternal hypotension or neonatal outcome. We retrieved randomized controlled trials that compared a fluid preload with coload in patients undergoing spinal anesthesia for elective Cesarean delivery. We graded the articles for quality of reporting (maximum score = 5) and recorded the incidence of hypotension, lowest blood pressure, the incidence of maternal nausea and vomiting, umbilical cord pH, and Apgar scores. We combined the results using random effects modelling. We retrieved eight studies comprised of 518 patients. The median quality score for the published studies was three. The incidence of hypotension in the coload group was 159/268 (59.3%) compared with 156/250 (62.4%) in the preload group (odds ratio [OR] = 0.93; 95% confidence interval [CI] 0.54–1.6). There were no significant differences between groups in any of the other outcomes. It is unnecessary to delay surgery in order to deliver a preload of fluid. Regardless of the fluid loading strategy, the incidence of maternal hypotension is high. Prophylactic or therapeutic vasopressors may be required in a significant proportion of patients.

Single-operator real-time ultrasound-guidance to aim and insert a lumbar epidural needle

Abstract: Purpose In conventional practice of epidural needle placement, determining the interspinous level and choosing the puncture site are based on palpation of anatomical landmarks, which can be difficult with some subjects. Thereafter, the correct passage of the needle towards the epidural space is a blind “feel as you go” method. An aim-and-insert single-operator ultrasound-guided epidural needle placement is described and demonstrated.

Intravenous dexmedetomidine, but not midazolam, prolongs bupivacaine spinal anesthesia.

Abstract: Purpose Midazolam has only sedative properties. However, dexmedetomidine has both analgesic and sedative properties that may prolong the duration of sensory and motor block obtained with spinal anesthesia. This study was designed to compare intravenous dexmedetomidine with midazolam and placebo on spinal block duration, analgesia, and sedation in patients undergoing transurethral resection of the prostate.

A randomized controlled trial demonstrates that a novel closed-loop propofol system performs better hypnosis control than manual administration

Abstract: The purpose of this randomized control trial was to determine the performance of a novel rule-based adaptive closed-loop system for propofol administration using the bispectral index (BIS®) and to compare the system’s performance with manual administration. The effectiveness of the closed-loop system to maintain BIS close to a target of 45 was determined and compared with manual administration. After Institutional Review Board approval and written consent, 40 patients undergoing major surgery in a tertiary university hospital were allocated to two groups using computer-generated block randomization. In the Closed-loop group (n = 20), closed-loop control was used to maintain anesthesia at a target BIS of 45, and in the Control group (n = 20), propofol was administered manually to maintain the same BIS target. To evaluate each technique’s performance in maintaining a steady level of hypnosis, the BIS values obtained during the surgical procedure were stratified into four clinical performance categories relative to the target BIS: ≤ 10%, 11-20%, 21-30%, or > 30% defined as excellent, good, poor, or inadequate control of hypnosis, respectively. The controller performance was compared using Varvel’s controller performance indices. Data were compared using Fisher’s exact test and the Mann-Whitney U test, P < 0.05 showing statistical significance. In the Closed-loop group, four females and 16 males (aged 54 ± 20 yr; weight 79 ± 7 kg) underwent anesthesia lasting 143 ± 57 min. During 55%, 29%, 9%, and 7% of the total anesthesia time, the system showed excellent, good, poor, and inadequate control, respectively. In the Control group, five females and 15 males (aged 59 ± 16 yr; weight 75 ± 13 kg) underwent anesthesia lasting 157 ± 81 min. Excellent, good, poor, and inadequate control were noted during 33%, 33%, 15%, and 19% of the total anesthesia time, respectively. In the Closed-loop group, excellent control of anesthesia occurred significantly more often (P < 0.0001), and poor and inadequate control occurred less often than in the Control group (P < 0.01). The median performance error and the median absolute performance error were significantly lower in the Closed-loop group compared with the Control group (-1.1 ± 5.3% vs -10.7 ± 13.1%; P = 0.004 and 9.1 ± 1.9% vs 15.7 ± 7.4%; P < 0.0001, respectively). The closed-loop system for propofol administration showed better clinical and control system performance than manual administration of propofol. (Clinical Trials gov. NCT 01019746).

The incidence of hypoxemia during surgery: evidence from two institutions

Abstract: Purpose The incidence of hypoxemia in patients undergoing surgery is largely unknown and may have a clinical impact. The objective of this study was to determine the incidence of intraoperative hypoxemia in a large surgical population.

Anesthesiologists' learning curves for ultrasound assessment of the lumbar spine.

Abstract: Background and objectives Ultrasound assessment of the lumbar spine to facilitate neuraxial anesthesia has recently received much attention. The transfer of knowledge pertaining to this skill has never been studied. The purpose of this study was to determine the amount of teaching needed to achieve competence in spinal ultrasound.

Characterization of intensive care unit acquired hyponatremia and hypernatremia following cardiac surgery.

Abstract: Although intensive care unit (ICU) acquired sodium disturbances are common in critically ill patients, few studies have examined sodium disturbances in patients following cardiac surgery. The objective of this study was to describe the epidemiology of ICU-acquired hyponatremia and hypernatremia in patients following cardiac surgery. We identified 6,727 adults (≥18 yr) who were admitted consecutively to a regional cardiovascular intensive care unit (CVICU) from January 1, 2000 to December 31, 2006 and were documented as having normal serum sodium levels (133 to 145 mmol·L−1) during the first day of ICU admission. ICU-acquired hyponatremia and hypernatremia were defined as a change in serum sodium concentration to 145 mmol·L−1, respectively, following ICU day one. A first episode of ICU-acquired hyponatremia and hypernatremia developed in 785 (12%) and 242 (4%) patients, respectively, (95% confidence interval [CI] 11-12% and 95% CI 3-4%, respectively), with a respective incidence density of 4.2 and 1.3 patients per 100 days of ICU admission (95% CI 4.0-4.5 and 95% CI 1.2-1.5). The incidence of ICU-acquired sodium disturbances varied according to the patients’ demographic and clinical variables for both hyponatremia (age, diabetes, Acute Physiology and Chronic Health Evaluation [APACHE II] score, mechanical ventilation, length of ICU stay, serum glucose level, and serum potassium level) and hypernatremia (APACHE II score, mechanical ventilation, length of hospital stay prior to ICU admission, length of ICU stay, serum glucose level, and serum potassium level). Compared with patients with normal serum sodium levels, hospital mortality was increased in patients with ICU-acquired hyponatremia (1.6% vs 10%, respectively; P < 0.001) and ICU-acquired hypernatremia (1.6% vs 14%, respectively; P < 0.001). ICU-acquired hyponatremia and hypernatremia are common complications in critically ill patients following cardiac surgery. They are associated with patient demographic and clinical characteristics and an increased risk of hospital mortality.

Hospital administrative database underestimates delirium rate after cardiac surgery.

Abstract: Administrative electronic databases are highly specific for postoperative complications, but they lack sensitivity. The objective of this study was to determine the incidence of delirium after cardiac surgery using a targeted prospectively collected dataset and to compare the findings with the incidence of delirium in the same cohort of patients identified in a hospital administrative database. Following Research Ethics Board approval, we compared delirium rates in a prospectively collected data research database with delirium rates in the same cohort of patients in an administrative hospital database where delirium was identified from codes entered by coding and abstracting staff. Every 12 hr postoperatively, delirium was assessed with a Confusion Assessment Method in the Intensive Care Unit. The administrative database contained the International Classification of Diseases version 10 (ICD-10) codes for patient diagnoses. The ICD-10 codes were extracted from the administrative database for each patient in the research database and were checked for the presence of the ICD-10 code for delirium. Data from a cohort of 1,528 patients were analyzed. Postoperative delirium was identified in 182 (11.9%) patients (95% confidence interval [CI], 10.3-13.5%) in the research dataset and 46 (3%) patients (95% CI, 2.2-3.8%) in the administrative dataset (P < 0.001). Thirteen (0.85%) patients who were coded for delirium in the administrative database were not identified in the research dataset. The median onset of postoperative delirium in these patients was significantly delayed (4 [3-9] days) compared with patients identified by both datasets (2 [1-9] days) and compared with patients from the research database only (1 [1-14] days) (P = 0.007). Postoperative delirium rates after cardiac surgery are underestimated by the hospital administrative database.

The Canadian STOP-PAIN project - Part 2: What is the cost of pain for patients on waitlists of multidisciplinary pain treatment facilities?

Abstract: The Canadian STOP-PAIN Project was designed to document the human and economic burden of chronic pain in individuals on waitlists of Multidisciplinary Pain Treatment Facilities (MPTF). This paper describes the societal costs of their pain. A subgroup of 370 patients was selected randomly from The Canadian STOP-PAIN Project. Participants completed a self-administered costing tool (the Ambulatory and Home Care Record) on a daily basis for three months. They provided information about publicly financed resources, such as health care professional consultations and diagnostic tests as well as privately financed costs, including out-of-pocket expenditures and time devoted to seeking, receiving, and providing care. To determine the cost of care, resources were valued using various costing methods, and multivariate linear regression was used to predict total cost. Overall, the median monthly cost of care was $1,462 (CDN) per study participant. Ninety-five percent of the total expenditures were privately financed. The final regression model consisted of the following determinants: educational level, employment status, province, pain duration, depression, and health-related quality of life. This model accounted for 35% of the variance in total expenditure (P < 0.001). The economic burden of chronic pain is substantial in patients on waitlists of MPTFs. Consequently, it is essential to consider this burden when making decisions regarding resource allocation and waitlist assignment for a MPTF. Resource allocation decision-making should include the economic implications of having patients wait for an assessment and for care.

Intravenous lidocaine does not reduce length of hospital stay following abdominal hysterectomy

Abstract: Purpose Intravenous lidocaine given both intraoperatively and postoperatively decreases pain scores, reduces opioid consumption, and promotes faster return of bowel function following abdominal surgery. The purpose of this trial was to determine if intravenous lidocaine limited to the intraoperative period reduces length of hospital stay and improves functional recovery following abdominal hysterectomy.

Up-down determination of the ED90 of oxytocin infusions for the prevention of postpartum uterine atony in parturients undergoing Cesarean delivery

Abstract: Introduction Use of the lowest effective dose of oxytocin may reduce side effects. This study was designed to determine the effective dose (ED)90 of oxytocin infusion for an elective Cesarean delivery (CD) to prevent uterine atony.

The FastrachTM Intubating Laryngeal Mask Airway®: an overview and update

Abstract: To provide an evidence-based overview and update on the use of the FastrachTM Intubating Laryngeal Mask Airway® (FT-LMA) when used within operative and non-operative settings The FT-LMA is available in three sizes to provide ventilation and the ability to pass an endotracheal tube (ETT) into the trachea blindly, semi-blindly, or with indirect visualization for patients over 30 kg The Chandy maneuver is recommended routinely; the first maneuver optimizes ventilation, and the second maneuver increases success at endotracheal intubation (ETI) The manufacturer’s reinforced tube or a pre-warmed or reversed standard ETT may be utilized Insertion and ventilation are successful in almost all patients Blind ETI is highly successful; adjuncts are generally not necessary The FT-LMA has a proven role in the airway management of anticipated difficult operating room (OR) intubations, unanticipated OR intubations, cervical spine injuries, and limited airway access situations Literature in the pre-hospital and emergency department settings is limited but favourable The FT-LMA has compared favourably with fibreoptic intubation, the LMA-Classic™, the laryngeal tube, and the CobraPLA™ Initially, the more expensive LMA CTrach™ appeared to be more successful, but overall it is not The FT-LMA airway seal pressures are excellent; serious complications are uncommon, and the FT-LMA figures prominently in most difficult airway guidelines The FT-LMA has proven to be a useful difficult airway device both within and outside of the operating room Effective ventilation is established in nearly all cases, and blind ETI is possible in the vast majority of cases if the optimal techniques described are used Serious complications are uncommon

The use of ultrasound for lumbar spinous process identification: A pilot study

Abstract: Background Clinical identification of lumbar spinous processes is inaccurate in most patients. The purpose of this study was to determine the number of patients required to train anesthesiologists in the use of ultrasound imaging to accurately identify the lumbar spinous processes.

Lumbar spinal stenosis: a brief review of the nonsurgical management

Abstract: Purpose The purpose of this brief narrative review is to summarize the evidence derived from randomized controlled trials pertaining to the nonsurgical treatment of lumbar spinal stenosis (LSS).

Renin-angiotensin blockade is associated with increased mortality after vascular surgery

Abstract: The outcome of patients with preoperative renin-angiotensin system (RAS) blockade, achieved either by angiotensin converting enzyme inhibitors or angiotensin receptor blocking agents, was assessed using 30-day mortality as a primary end point An observational cohort study of 883 consecutive patients undergoing elective open abdominal aortic aneurysm repair (AAA) was undertaken and analyzed using a propensity score matched study The data collected included medical history, anesthetic techniques, and postoperative outcomes Logistic regression analysis identified predictors of RAS blockade: hypertension, stroke, congestive heart failure, diabetes, and heart disease A propensity score for RAS blockade was calculated for each subject using several factors: age, sex, serum creatinine, hypertension, heart disease, congestive heart failure, stroke, diabetes, and exposure to cardiovascular medications Subjects and controls were matched using the calculated propensity score The overall 30-day mortality rate was 35% (31/883 patients) The crude mortality rate in RAS blocked patients was 58% (21/359) vs 19% (10/524) in unexposed patients (odds ratio 32, with 95% confidence intervals [CI95] 15-67; P < 0001) Analysis of 261 propensity score matched pairs showed a 30-day mortality rate of 61% (16/261) in the RAS blocked group vs 15% (4/261) in unblocked patients (P = 0008) The estimated odds ratio for 30-day mortality associated with RAS blockade was 50 (CI95 14-27) Examination of 883 cases of AAA repair showed increased mortality associated with preoperative RAS blockade A better understanding of perioperative pharmacology and physiology of RAS blockade is needed as well as future studies to identify causality

Glycosylated hemoglobin levels and outcome in non-diabetic cardiac surgery patients

Abstract: In diabetics, elevated preoperative hemoglobin A1c (HbA1c) levels are associated with increased complication rates after cardiac surgery. While many non-diabetics also have elevated HbA1c, the relationship with outcome in these patients is not well understood. Therefore, in a cohort of non-diabetic patients, we tested the hypothesis that preoperative HbA1c is associated with early mortality risk after cardiac surgery. In this retrospective observational study, we accessed data from a prospectively collected quality assurance database for a cohort of 1,474 non-diabetic elective cardiac surgery patients with documented preoperative HbA1c levels. The relationship of HbA1c with death within 30 days of surgery was examined using logistic regression modeling. Acute kidney injury and infection were similarly assessed using multivariable linear and logistic regression. Thirty-one percent of patients (n = 456) had elevated HbA1c values (>6.0%). Patients with elevated HbA1c had higher fasting and peak intraoperative blood glucose values. Also, an elevated HbA1c level was independently associated with increased 30-day mortality (odds ratio 1.53 per percent increase [1.24-1.91]; P = 0.0005). This relationship persisted even after “borderline” diabetics were excluded. Furthermore, acute kidney injury was associated with elevated baseline HbA1c (P = 0.01). No association was found between HbA1c and postoperative infection risk (P = 0.48). In non-diabetics, an elevated preoperative HbA1c level (>6.0%) is independently associated with significantly greater early mortality risk after elective cardiac surgery. Our findings suggest that HbA1c may have value as a screening tool to identify high-risk non-diabetic cardiac surgery patients.

Ultrasound-guided suprascapular nerve block: a correlation with fluoroscopic and cadaveric findings

Abstract: Purpose Previous work on the ultrasound-guided injection technique and the sonoanatomy of the suprascapular region relevant to the suprascapular nerve (SSN) block suggested that the ultrasound scan showed the presence of the suprascapular notch and transverse ligament. The intended target of the ultrasound-guided injection was the notch. The objective of this case report and the subsequent cadaver dissection findings is to reassess the interpretation of the ultrasound images when locating structures for SSN block.

Incomplete adherence to the ASA difficult airway algorithm is unchanged after a high-fidelity simulation session

Abstract: Although guidelines for difficult airway management have been published, the extent to which consultant anesthesiologists follow these guidelines has not been determined. The purpose of this study is to observe how consultant anesthesiologists manage a “cannot intubate, cannot ventilate” (CICV) scenario in a high-fidelity simulator and to evaluate whether a simulation teaching session improves their adherence to the American Society of Anesthesiologists (ASA) difficult airway algorithm. With Ethics Board approval and informed consent, all staff anesthesiologists in a single tertiary care institution were invited to enrol in this study where they managed a simulated unanticipated CICV scenario in a high-fidelity simulator. The scenario involved a patient with a difficult airway whose trachea could not be intubated and where it was impossible to ventilate the patient’s lungs. Airway management options, including laryngeal mask airway, a fibreoptic bronchoscope, and a Glidescope® were available for use but scripted to fail. A percutaneous cricothyroidotomy was required to re-establish adequate ventilation. Following the scenario, there was a personalized one-hour video-assisted expert debriefing focusing on the ASA difficult airway guidelines and “hands-on” cricothyroidotomy teaching. The second scenario followed immediately with an identical CICV scenario. The content to either scenario was not revealed beforehand. Outcome measures included: 1) major deviations from the ASA difficult airway guidelines; 2) time to start cricothyroidotomy; and 3) time to achieve ventilation. Thirty-eight anesthesiologists agreed to participate. The number of major deviations from the ASA algorithm was similar in the first and second sessions. These deviations included: multiple laryngoscopies (0 vs 2 pre-post; P = 0.49), use of fibreoptic bronchoscope (8 vs 7 pre-post; P = 1.0), bypass of laryngeal mask airway attempt (7 vs 13 pre-post; P = 0.19), and failure to call for anesthetic help (12 vs 8 pre-post; P = 0.43). However, more participants failed to call for surgical help in the second session (7 vs 16; P = 0.04). The times to start cricothyroidotomy and the times to achieve ventilation were significantly shorter in the second session (205.5 ± 61.3 sec vs 179.7 ± 65.1 sec; P = 0.01 and 356.9 ± 117.2 sec vs 269.4 ± 77.43 sec; P = 0.0002, respectively). No substantial changes in airway management in a CICV scenario were observed after an intense one-hour personalized video-assisted airway-focused simulation debriefing session with an expert. It appears that multiple factors other than airway algorithms come into play in emergency airway decision-making processes, including one’s personal clinical experience with the many available airway devices.

A report of fulminant malignant hyperthermia in a patient with a novel mutation of the CACNA1S gene.

Abstract: To report the identification of a novel mutation in the CACNA1S gene that encodes the alpha-1-subunit (Cav1.1) of the voltage-gated skeletal muscle L-type calcium channel in a patient with malignant hyperthermia. An otherwise healthy 34-yr-old female developed fulminant malignant hyperthermia (MH) under sevoflurane anesthesia during laparoscopic donor nephrectomy. The first sign was an increase in end-tidal CO2. Malignant hyperthermia was suspected early, and resuscitative measures, including supportive and specific treatment, were successfully implemented. The patient rejected the open muscle biopsy for the Caffeine-Halothane Contracture Test (CHCT); therefore, only molecular genetic testing was performed. Sequencing of the entire ryanodine receptor type 1 transcript did not reveal any MH causative mutations. However, a novel homozygous mutation, p.Arg1086Ser, was identified in the CACNA1S gene that encoded for the alpha-1-subunit of the skeletal muscle L-type calcium channel (Cav1.1). A CACNA1S mutation, p.Arg1086His, involving the same Arg1086 residue that is mutated in our patient has previously been reported in association with MH in three independent families. The homozygous p.Arg1086Ser mutation of CACNA1S, the gene that encodes the alpha-1-subunit of the voltage-gated skeletal muscle L-type calcium channel, is a novel mutation associated with malignant hyperthermia.

Review article: Acute kidney injury in critical illness

Abstract: Purpose This review provides a focused and comprehensive update on emerging evidence related to acute kidney injury (AKI).

Comparative efficacy of ultrasound-guided and stimulating popliteal-sciatic perineural catheters for postoperative analgesia

Abstract: Purpose Perineural catheter insertion using ultrasound guidance alone is a relatively new approach. Previous studies have shown that ultrasound-guided catheters take less time to place with high placement success rates, but the analgesic efficacy compared with the established stimulating catheter technique remains unknown. We tested the hypothesis that popliteal-sciatic perineural catheter insertion relying exclusively on ultrasound guidance results in superior postoperative analgesia compared with stimulating catheters.