Pui San Loh

Comparing the efficacy and safety between propofol and dexmedetomidine for sedation in claustrophobic adults undergoing magnetic resonance imaging (PADAM trial)

STUDY OBJECTIVE To determine the efficacy of sedation with dexmedetomidine compared to propofol for claustrophobic adults undergoing magnetic resonance imaging (MRI) in our institution. DESIGN Randomized, prospective, double-blinded study. SETTING University-based tertiary referral center. PATIENTS Thirty claustrophobic adults with American Society of Anesthesiologists physical status I and II who were planned for MRI. INTERVENTIONS Patients were randomly assigned to target-controlled infusion propofol or dexmedetomidine loading followed by maintenance dose for procedural sedation. MEASUREMENTS AND MAIN RESULTS The primary end point was adequate reduction in patient anxiety levels to allow successful completion of the MRI sequence. Both methods of sedation adequately reduced anxiety levels in visual analog scale scores and Spielberger Strait Test Anxiety Inventory (P<.001). Dexmedetomidine required a longer time to achieve anxiolysis, 7.36minutes (SD, 2.59), and required increasing maintenance dose to induce sleep compared to 10.71minutes (SD, 4.63) for propofol. In terms of image quality, 2 patients (16.67%) in the dexmedetomidine group were satisfactory, whereas all with propofol were graded as good to excellent. Adverse effects were seen in patients sedated with dexmedetomidine with number needed to harm 8 for hypotension and 15 for bradycardia compared to none recorded in the propofol arm. There was no significant difference in patient satisfaction scores or home readiness after the MRI. CONCLUSIONS Both dexmedetomidine and propofol can effectively reduce anxiety levels of claustrophobic adults undergoing MRI, but dexmedetomidine takes longer to achieve adequate anxiolysis and sleep and may have an effect on image quality. Hypotension and bradycardia are common adverse effects observed with dexmedetomidine.

Intra-operative cell salvage and sickle cell trait in liver transplantation: time to reconsider?

Sickle cell trait (SCT), characterized by the sickle hemoglobin (HbS) gene in a heterozygous state is the most common hemoglobinopathy worldwide that is typically asymptomatic in affected individuals [1]. In Europe, migration has increased the prevalence, raising concerns about its clinical impact [1]. For example, the use of intraoperative cell salvage may induce sickling because of hypoxia during processing [2]. This article is protected by copyright. All rights reserved.

Rationale and design for the detection and neurological impact of cerebrovascular events in non-cardiac surgery patients cohort evaluation (NeuroVISION) study: a prospective international cohort study

Objectives Covert stroke after non-cardiac surgery may have substantial impact on duration and quality of life. In non-surgical patients, covert stroke is more common than overt stroke and is associated with an increased risk of cognitive decline and dementia. Little is known about covert stroke after non-cardiac surgery. NeuroVISION is a multicentre, international, prospective cohort study that will characterise the association between perioperative acute covert stroke and postoperative cognitive function. Setting and participants We are recruiting study participants from 12 tertiary care hospitals in 10 countries on 5 continents. Participants We are enrolling patients ≥65 years of age, requiring hospital admission after non-cardiac surgery, who have an anticipated length of hospital stay of at least 2 days after elective non-cardiac surgery that occurs under general or neuraxial anaesthesia. Primary and secondary outcome measures Patients are recruited before elective non-cardiac surgery, and their cognitive function is measured using the Montreal Cognitive Assessment (MoCA) instrument. After surgery, a brain MRI study is performed between postoperative days 2 and 9 to determine the presence of acute brain infarction. One year after surgery, the MoCA is used to assess postoperative cognitive function. Physicians and patients are blinded to the MRI study results until after the last patient follow-up visit to reduce outcome ascertainment bias. We will undertake a multivariable logistic regression analysis in which the dependent variable is the change in cognitive function 1 year after surgery, and the independent variables are acute perioperative covert stroke as well as other clinical variables that are associated with cognitive dysfunction. Conclusions The NeuroVISION study will characterise the epidemiology of covert stroke and its clinical consequences. This will be the largest and the most comprehensive study of perioperative stroke after non-cardiac surgery. Trial registration number NCT01980511; Pre-results.

Intraoperative Magnetic Resonance Imaging

Neurosurgery and its pairing with magnetic resonance imaging (MRI) technology has evolved over the last few decades to fulfil the needs of demanding new clinical requirements. With advancement of increasingly sophisticated and modern equipment, MRI scanning intraoperatively has assumed an invaluable role in providing constantly updated images for neuronavigation in tumour excision and biopsies. The accuracy produced benefits in eliminating the effect of brain shift to allow improved gross tumour resection rates and minimal surgical damage. Although useful in many ways, it must be recognized that providing anaesthesia for intraoperative MRI (iMRI) differs from anaesthesia solely for either MRI or neurosurgery alone. Successful conduct of iMRI depends on meticulous attention to details on MRI safety, adequate training of designated care providers and efficient communication within a working team. This chapter describes the types of iMRI available, a general workflow and anaesthetic concerns in providing care for these neurosurgical cases.

Combining glidescope and fiber-optic for intubation in oral maxillofacial surgery

Airway management for patients with recent oral facial injuries is always a challenge for the anesthetist. We describe how the glidescope (GLS) and fiber-optic (FOB) can be effectively combined in three patients undergoing oral maxillofacial surgeries after sustaining multiple facial fractures from trauma to allow less traumatic intubation, an option to visualize on either monitor and faster intubating time (mean 1 min 14 s for our cases) compared to the use of either one alone. Although it allows for better visualization of the vocal cords, it requires 2 trained anaesthetists to perform and this would need to be considered when using this technique.

Handedness in man: The energy availability hypothesis

More than 90% of the human species are right handed. Although outwardly our body appears symmetrical, a 50/50% lateralization in handedness never occurs. Neither have we seen more than 50% left handedness in any subset of the human population. By 12-15weeks of intrauterine life, as many as 6 times more fetuses are noted by ultrasound studies to be sucking on their right thumbs. Distinct difference in oxygenation leading to dissimilar energy availability between right and left subclavian arteries in place by week 9 of life may hold the clue to the lateralization of hand function and eventually, the same in the brain. We know there is a higher incidence of left handedness in males, twins, premature babies and those born to mothers who smoke. They may represent a subset with less distinct difference in oxygenation between the 2 subclavian arteries during the fetal stage. This hypothesis if correct not only closes the gap in understanding human handedness and lateralization but also opens a vista for new research to focus on in utero tissue energy availability and its impact on outcome in life.