Search

Background: Neuraxial analgesia is preferred over general anesthesia for cesarean delivery (CD), particularly in the presence of a labor epidural catheter. We hypothesize that care by a non-obstetric anesthesiologist as compared to care by an obstetric anesthesiologist is associated with a higher risk for use of general anesthesia for CD for patients with a preexisting labor epidural catheter., Methods: To determine whether fellowship status of the covering anesthesiologist was a risk factor for general anesthesia, we retrospectively investigated the rate of general anesthesia use in patients with epidural catheters placed for labor analgesia who subsequently required CD. To standardize the practice environment under which these cases occurred, we examined only cases which occurred during coverage by the call team on nights, weekends, and holidays., Results: There were 1820 cases in which a patient had epidural labor analgesia followed by a CD. Nine hundred and twelve cases were covered by an obstetric anesthesiologist and 908 cases were covered by a non-obstetric anesthesiologist. General anesthesia was used in only 16 of these cases. General anesthesia was more likely to be performed by non-obstetric fellowship trained anesthesiologists (1.54% or 14/908 compared to 0.22% or 2/912; P = 0.002)., Conclusions: This investigation suggests that the presence of an obstetric fellowship-trained anesthesiologist may be a predictor of decreased rate of general anesthesia use in patients with preexisting indwelling labor epidural catheters., (© 2019 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Aim: To compare readmission rates between patients with sickle cell disease (SCD) and non-sickle cell disease undergoing total hip and knee arthroplasty (THA and TKA)., Methods: Identified adult patients who underwent THA or TKA from 2007 to 2014 in California, Florida, New York, Maryland and Kentucky using a multistate database. Outcomes were 30- and 90-day readmission rates, mortality, complications, length of stay and hospital charges. Logistic regression models were used for analysis., Results: Compared with non-sickle cell disease patients following TKA and THA, SCD patients had higher odds of 30- (odds ratio [OR]: 3.79) and 90-day readmissions (OR: 4.15), mortality (OR: 6.54), more complications, longer length of stay, and higher total charges., Conclusion: Following TKA and THA, SCD is associated with higher readmissions and worse outcomes.

Objective: To summarize the evidence on the hemodynamic, echocardiographic, and clinical effects of inhaled and intravenous milrinone (iMil and IvMil) in adult cardiac surgery patients., Design: Systematic review, pairwise and network meta-analysis., Setting: Multi-institutional., Participants: Adult cardiac surgery patients., Interventions: Comparison between iMil and IvMil versus other agents or placebo., Measurements and Main Results: The primary endpoints were mean pulmonary artery pressure (MPAP) and peripheral vascular resistance (PVR). Secondary endpoints included the following: (1) mean arterial pressure, heart rate, and cardiac index (CI); (2) echocardiographic data; and (3) clinical outcomes. Random model, leave-one-out-analysis, and meta-regression were used. Thirty studies (6 iMil and 24 IvMil) were included for a total of 1,438 patients (194 iMil and 521 IvMil). IvMil was associated with a lower MPAP, lower PVR, and higher CI compared to placebo (standardized mean difference [SMD] = -0.22 [95% CI = -0.48 to 0.05], SMD = -0.49 [95% CI = -0.71 to -0.27], and SMD = 0.94 [95% CI = 0.51 to 1.37]). No difference in any outcome was found between iMil and placebo. At network meta-analysis, significantly lower PVR and shorter hospital length of stay were found for IvMil compared to iMil (SMD = -0.82 [95% CI = -1.53 to -0.10] and SMD = -0.50 [95% CI = -0.95 to -0.05], respectively)., Conclusion: These results support the clinical use of IvMil in cardiac surgery patients. No evidence at present supports the adoption of iMil., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background and Purpose: Dopamine and glutamate reciprocally regulate each other in some of the neurocircuits affected by Parkinson's disease (PD). The objective of this pilot study was to explore relationships between these neurotransmitter systems with positron emission tomography., Methods: The sample consisted of nine patients with PD and eight healthy volunteers (HVs). Dynamic images of the brain were acquired after the IV administration of ∼370 MBq (10 mCi) of [ 11 C]PE2i, a dopamine transporter (DaT) imaging agent, and ∼185 MBq (∼5 mCi) of [ 18 F]FPEB, a selective metabotropic glutamate receptor 5 (mGluR5) antagonist. Multiple volumes of interest were semiautomatically placed on contemporaneously acquired MRI scans. Nondisplaceable binding potentials (BP ND ) were calculated with the Logan reference tissue model using cerebellar white matter as the reference region., Results: The findings showed that average [ 18 F]FPEB BP ND values were slightly more than 20% higher in PD than HVs in several mesocortical regions, including the bilateral putamen (P = .01), hippocampus (P = .02), and amygdala (P = .05). Average [ 11 C]PE2i BP ND was significantly reduced by about half or more in patients with PD in the bilateral caudate (P < .001) and putamen (P < .001)., Conclusions: mGluR5 seems upregulated in strategic dopaminergic brain regions adversely affected by PD. The findings seem to confirm that DaT tracers are better discriminatory biomarkers for diagnosing PD; however, mGluR5 tracers might deserve further exploration as potential biomarkers of response in clinical trials., (© 2018 by the American Society of Neuroimaging.)

Background: Ketamine is a general anaesthetic with anti-depressant effects at subanaesthetic doses. We hypothesised that intraoperative administration of ketamine would prevent or mitigate postoperative depressive symptoms in surgical patients., Methods: We conducted an international, randomised clinical trial testing the effects of intraoperative administration of ketamine [0.5 mg kg -1 (Lo-K) or 1.0 mg kg -1 (Hi-K)] vs control [saline placebo (P)] in patients ≥60 yr old undergoing major surgery with general anaesthesia. We administered the Patient Health Questionnaire-8 before the operation, on postoperative day (POD) 3 (primary outcome), and on POD30 to assess depressive symptoms, a secondary outcome of the original trial., Results: There was no significant difference on POD3 in the proportion of patients with symptoms suggestive of depression between the placebo [23/156 (14.7%)] and combined ketamine (Lo-K plus Hi-K) [61/349 (17.5%)] groups [difference = -2.7%; 95% confidence interval (CI), 5.0% to -9.4%; P=0.446]. Of the total cohort, 9.6% (64/670; 95% CI, 7.6-12.0%) had symptoms suggestive of depression before operation, which increased to 16.6% (84/505; 95% CI, 13.6-20.1%) on POD3, and decreased to 11.9% (47/395; 95% CI, 9.1-15.5%) on POD30. Of the patients with depressive symptoms on POD3 and POD30, 51% and 49%, respectively, had no prior history of depression or depressive symptoms., Conclusions: Major surgery is associated with new-onset symptoms suggestive of depression in patients ≥60 yr old. Intraoperative administration of subanaesthetic ketamine does not appear to prevent or improve depressive symptoms., Clinical Trials Registration: NCT01690988., (Copyright © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

Background and Purpose: Neuroinflammation has been implicated in the pathophysiology of Parkinson's disease (PD), which might be influenced by successful neuroprotective drugs. The uptake of [ 11 C](R)-PK11195 (PK) is often considered to be a proxy for neuroinflammation, and can be quantified using the Logan graphical method with an image-derived blood input function, or the Logan reference tissue model using automated reference region extraction. The purposes of this study were (1) to assess whether these noninvasive image analysis methods can discriminate between patients with PD and healthy volunteers (HVs), and (2) to establish the effect size that would be required to distinguish true drug-induced changes from system variance in longitudinal trials., Methods: The sample consisted of 20 participants with PD and 19 HVs. Two independent teams analyzed the data to compare the volume of distribution calculated using image-derived input functions (IDIFs), and binding potentials calculated using the Logan reference region model., Results: With all methods, the higher signal-to-background in patients resulted in lower variability and better repeatability than in controls. We were able to use noninvasive techniques showing significantly increased uptake of PK in multiple brain regions of participants with PD compared to HVs., Conclusion: Although not necessarily reflecting absolute values, these noninvasive image analysis methods can discriminate between PD patients and HVs. We see a difference of 24% in the substantia nigra between PD and HV with a repeatability coefficient of 13%, showing that it will be possible to estimate responses in longitudinal, within subject trials of novel neuroprotective drugs., (© 2018 The Authors. Journal of Neuroimaging published by Wiley Periodicals, Inc. on behalf of American Society of Neuroimaging.)

OBJECTIVE The objective of this study was to evaluate the utility of diffusion tensor imaging (DTI) tractography-based targeting of the dentatorubrothalamic tract (DRT) for magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy in patients with essential tremor (ET) and correlate postprocedural tract disruption with clinical outcomes. METHODS Four patients received preprocedural and immediate postprocedural DTI in addition to traditional anatomical MRI sequences for MRgFUS thalamotomy. Optimal ablation sites were selected based on the patient-specific location of the DRT as demonstrated by DTI (direct targeting) and correlated with traditional atlas-based measurements for thalamic ventral intermediate nucleus (Vim) lesioning (indirect targeting). Fiber tracts were displayed three-dimensionally during the procedure and used in conjunction with clinical signs of tremor control for fine correction of the ablation site. Immediately following the conclusion of the procedure, the MRgFUS head frame was removed and patients were placed in a 32-channel MRI head coil for follow-up DTI and anatomical MRI sequences. RESULTS All patients had excellent postoperative tremor control and successful pre- and postprocedural DTI fiber tracking of the corticospinal tract, medial lemniscus, and DRT. Immediate postprocedure DTI failed to track the DRT ipsilateral to the lesion site with a preserved contralateral DRT, coincident with substantial resolution of contralateral tremor. CONCLUSIONS DTI can reliably identify the optimal ablation target and demonstrates tract disruption on immediate postprocedural imaging. A clinical improvement of ET was observed immediately following the procedure, correlating with DRT disruption and suggesting that interruption of the DRT is a consequence of clinically successful MRgFUS thalamotomy. These findings may have utility for both MRgFUS procedure planning in surgically naive patients and retreatment of patients who have previously undergone unsuccessful thalamic Vim lesioning.

Purpose of Review: We present a focused review on postoperative delirium for anesthesiologists, encompassing clinical features, neuropathogenesis, and clinical identification and management strategies based on risk factors and current delirium treatments., Recent Findings: The literature on postoperative delirium is dominated by non-experimental studies. We review delirium phenotypes, diagnostic criteria, and present standard nomenclature based on current literature. Disruption of cortical integration of complex information (CICI) may provide a framework to understand the neuropathogenesis of postoperative delirium, as well as risk factors and clinical modifiers in the perioperative period. We further divide risk factors into patient factors, surgical factors, and medical/pharmacological factors, and present specific considerations for each in the preoperative, intraoperative, and postoperative periods., Summary: Postoperative delirium is prevalent, poorly understood, and often missed with current screening techniques. Proper identification of risk factors is useful for perioperative interventions and can help tailor patient-specific management strategies., Competing Interests: CONFLICT OF INTEREST Seyed A. Safavynia, Sona Arora, Kane O. Pryor, and Paul S. García all declare that they have no conflict of interest.

Background: Cerebrospinal-fluid (CSF) drainage is recommended by current guidelines for spinal protection during open and endovascular repairs of thoracic and thoraco-abdominal aortic aneurysms. In the published literature, great variability exists in the rate of CSF-related complications and morbidity. Herein, we perform a systematic review and meta-analysis on the incidence of CSF drainage-related complications, and compare the complication rates between open and endovascular repairs., Methods: The systematic review was conducted according to the Meta-Analysis of Observational Studies in Epidemiology guidelines. Thirty-four studies (4714 patients) were included in the quantitative analysis. The CSF drainage-related complications were categorised as mild, moderate, and severe. Pooled event rates for each complication category were estimated using a random-effect model. Random-effect uni- and multivariable meta-regression analyses were used to assess the effect of aortic-repair approach (open vs endovascular) and the CSF drainage criteria on CSF drainage-related complications., Results: The pooled event rates were 6.5% [95% confidence interval (CI): 4.3-9.8%] for overall complications, 2% (95% CI: 1.1-3.4%) for minor complications, 3.7% (95% CI: 2.5-5.6%) for moderate complications, and 2.5% (95% CI: 1.6-3.8%) for severe complications. The drainage-related-mortality pooled event rate was 0.9% (95% CI: 0.6-1.4%). The uni- and multivariable meta-regression analyses showed no difference in complication rates between the open and endovascular approaches, or between the different CSF drainage protocols., Conclusion: The complication rate for CSF drainage is not negligible. Our results help define a more accurate risk-benefit ratio for CSF drain placement at the time of repair of thoracic and thoraco-abdominal aneurysms., (Copyright © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

Background: Postoperative atrial fibrillation (POAF) is a common complication following cardiac surgery. POAF is associated with increased morbidity and hospital costs. We herein describe the protocol for a randomized controlled trial to determine if performing a posterior left pericardiotomy prevents POAF after cardiac surgery., Methods/design: All patients submitted to cardiac surgery at our institution will be screened for inclusion into the study. The study will consist of two parallel arms with random allocation between groups to either receive a posterior left pericardiotomy or serve as a control. Masking will be done in a single-blinded fashion to the patient. Patients will be continuously monitored postoperatively for the occurrence of atrial fibrillation until discharge. At the follow-up clinic visit (15-30 days after surgery), the primary endpoint (atrial fibrillation) and other secondary endpoints, such as pleural or pericardial effusion, will be assessed. A total sample size of 350 subjects will be recruited., Discussion: POAF is associated with increased morbidity, prolonged hospital stay, and increased costs after cardiac surgery. Several strategies aimed at reducing the incidence of POAF have been investigated, including beta-blockers, amiodarone, and statins, all with suboptimal results. Posterior left pericardiotomy has been associated with a reduction of POAF in previous series. However, these studies had limited sample sizes and suboptimal methodology, so that the efficacy of posterior pericardiotomy in preventing POAF remains to be definitively proven. Our randomized trial aims to determine the effect of a posterior left pericardiotomy on the incidence of POAF., Trial Registration: ClinicalTrials.gov, ID: NCT02875405 , protocol record 1502015867. Registered on July 2016.

Background: Interest in global health during postgraduate residency training is increasing across medical specialties, and multiple disciplines have categorized global health training opportunities in their arena. No such cataloging exists for anesthesiology residency programs. The aim of this study was to assess and characterize global health opportunities and the attitudes of program directors (PDs) in U.S. anesthesiology residency programs towards this training., Methods: A cross-sectional 20-question survey on global health opportunities was distributed to 128 ACGME accredited anesthesiology residency program directors via email between October 2015 and January 2016. Descriptive statistics and exploratory inferential analyses were applied. Maximal nonresponse selection bias was estimated., Results: The overall response rate was 44%. Of those who responded, 61% reported that their residency program had a global health elective, with a maximal bias estimate of 6.5%. 45% of program directors with no global health elective reported wanting to offer one. 77% of electives have articulated educational goals, but there is substantial heterogeneity in curricula offered. Program director attitudes regarding the value of global health programs differed significantly between those with and without existing programs., Conclusions: The proportion of U.S. anesthesiology residency programs offering global health electives is similar to that in other medical specialties. There is inconsistency in program structure, goals, curriculum, and funding. Attitudes of program directors differ between programs with and without electives, which may reflect bidirectional influence to be investigated further. Further studies are needed to codify curricula, assess effectiveness, and validate methodologies.

Background: Delirium is a common and serious postoperative complication. Subanaesthetic ketamine is often administered intraoperatively for postoperative analgesia, and some evidence suggests that ketamine prevents delirium. The primary purpose of this trial was to assess the effectiveness of ketamine for prevention of postoperative delirium in older adults., Methods: The Prevention of Delirium and Complications Associated with Surgical Treatments [PODCAST] study is a multicentre, international randomised trial that enrolled adults older than 60 years undergoing major cardiac and non-cardiac surgery under general anaesthesia. Using a computer-generated randomisation sequence we randomly assigned patients to one of three groups in blocks of 15 to receive placebo (normal saline), low-dose ketamine (0·5 mg/kg), or high dose ketamine (1·0 mg/kg) after induction of anaesthesia, before surgical incision. Participants, clinicians, and investigators were blinded to group assignment. Delirium was assessed twice daily in the first 3 postoperative days using the Confusion Assessment Method. We did analyses by intention-to-treat and assessed adverse events. This trial is registered with clinicaltrials.gov, number NCT01690988., Findings: Between Feb 6, 2014, and June 26, 2016, 1360 patients were assessed, and 672 were randomly assigned, with 222 in the placebo group, 227 in the 0·5 mg/kg ketamine group, and 223 in the 1·0 mg/kg ketamine group. There was no difference in delirium incidence between patients in the combined ketamine groups and the placebo group (19·45% vs 19·82%, respectively; absolute difference 0·36%, 95% CI -6·07 to 7·38, p=0·92). There were more postoperative hallucinations (p=0·01) and nightmares (p=0·03) with increasing ketamine doses compared with placebo. Adverse events (cardiovascular, renal, infectious, gastrointestinal, and bleeding), whether viewed individually (p value for each >0·40) or collectively (36·9% in placebo, 39·6% in 0·5 mg/kg ketamine, and 40·8% in 1·0 mg/kg ketamine groups, p=0·69), did not differ significantly across groups., Interpretation: A single subanaesthetic dose of ketamine did not decrease delirium in older adults after major surgery, and might cause harm by inducing negative experiences., Funding: National Institutes of Health and Cancer Center Support., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Patient memories of the operating room (OR) may serve as the informational basis for assessing satisfaction with individual anesthesiologists. Furthermore, the provision of clinically important information may assume that perioperative memories are retained. Studies assessing the extent of perioperative amnesia and factors associated with perioperative amnesia are sparse. Therefore, we assessed patient amnesia of the OR and of the preoperative holding area in hospitals where midazolam is typically administered in the preoperative holding area and evaluated whether midazolam dose administered in the preoperative holding area and patient age were associated with amnesia of the OR before induction of anesthesia., Methods: This was a retrospective study among 7750 adult patients who had general anesthesia and participated in the B-Unaware and Bispectral Index or Anesthetic Gas to Reduce Explicit Recall (BAG-RECALL) clinical trials. The last location the patient remembered before induction of anesthesia and the first location they remembered after induction of anesthesia were determined through a modified Brice questionnaire administered over the phone 30 days postoperatively. Regarding the preoperative period, patients were excluded if their last memory was unclear with respect to location before induction of anesthesia or if they were recruited at Winnipeg, where midazolam was typically first administered in the OR. Midazolam dose (mg/kg) administered in the preoperative holding area was divided into quartiles. Poisson regression models were used to calculate age- and multivariable-adjusted odds ratios (95% confidence intervals [CIs]) for the association between midazolam dose and amnesia of the OR before induction of anesthesia., Results: Of the 5339 patients included, 59.5% (95% CI, 58.2–60.9) of patients had amnesia of the OR before induction of anesthesia. In addition, 44.1% (95% CI, 42.8–45.7) last remembered the preoperative holding area, and 15.4% (95% CI, 14.4–16.4) only had preoperative memories before the holding area. The percentages of patients with amnesia of the OR before induction of anesthesia differed according to age groups: 50.7% (95% CI, 47.7%–53.7%) in patients aged 18 to 47 years versus 70.0% (95% CI, 67.0%–72.9%) in patients aged 73 to 99 years. Patients in the highest midazolam quartile had an adjusted prevalence ratio of 1.31 (95% CI, 1.22–1.42) for amnesia of the OR compared with those who did not receive midazolam., Conclusions: In hospitals where patients typically receive midazolam in the preoperative holding area, the majority of patients do not remember the OR, and a clinically relevant number of patients does not remember the preoperative holding area. If additional studies produce results indicating that a substantial proportion of patients has amnesia of the anesthesiologist, these findings would argue against the validity of assessing patient satisfaction with individual anesthesiologists providing exclusively OR care in such hospitals. Furthermore, if additional studies yield findings suggesting patient amnesia of the preoperative holding area, these results would suggest reconsideration of providing clinically important information only in the preoperative holding area. Older age and midazolam-induced anterograde amnesia are probably associated with impaired perioperative memories.

Background: Subclinical doses of propofol produce anterograde amnesia, characterized by an early failure of memory consolidation. It is unknown how propofol affects the amygdala-dependent emotional memory system, which modulates consolidation in the hippocampus in response to emotional arousal and neurohumoral stress. We present an event-related functional magnetic resonance imaging study of the effects of propofol on the emotional memory system in human subjects., Methods: Thirty-five healthy subjects were randomized to receive propofol, at an estimated brain concentration of 0.90 μg ml(-1), or placebo. During drug infusion, emotionally arousing and neutral images were presented in a continuous recognition task, while blood-oxygen-level-dependent activation responses were acquired. After a drug-free interval of 2 h, subsequent memory for successfully encoded items was assessed. Imaging analysis was performed using statistical parametric mapping and behavioural analysis using signal detection models., Results: Propofol had no effect on the stereotypical amygdalar response to emotional arousal, but caused marked suppression of the hippocampal response. Propofol caused memory performance to become uncoupled from amygdalar activation, but it remained correlated with activation in the posterior hippocampus, which decreased in proportion to amnesia., Conclusions: Propofol is relatively ineffective at suppressing amygdalar activation at sedative doses, but abolishes emotional modulation and causes amnesia via mechanisms that commonly involve hyporesponsiveness of the hippocampus. These findings raise the possibility that amygdala-dependent fear systems may remain intact even when a patient has diminished memory of events. This may be of clinical importance in the perioperative development of fear-based psychopathologies, such as post-traumatic stress disorder., Clinical Trial Registration: NCT00504894., (© The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background and Objectives: Ophthalmic arterial chemosurgery for retinoblastoma has been associated with intraoperative decreases in respiratory compliance. Through the analysis of data from computerized records, we objectively defined severe respiratory compliance events and correlated them with demographic and clinical information in patients undergoing this procedure., Methods: Data were collected from ophthalmic arterial chemosurgery cases from 2006 to 2013. Intraoperative PIP, PEEP, TV, SpO2 , and EtCO2 were analyzed. Compliance changes, desaturations, decreases in EtCO2 , and clinical outcomes were assessed., Results: Respiratory compliance decreases with a bimodal distribution. Severe events were defined as exhibiting a minimum compliance decrease of 40%. Seventy-eight of 122 children (64%) experienced a severe compliance event during at least one treatment, and it occurred in 137/468 cases (29%). A subset of 94 children had complete or at least the first three records. The incidence of a severe respiratory compliance event in this subgroup was 17/94 (18%) on the first and 84/261 (32%) on subsequent procedures. The probability of developing a severe respiratory compliance event on a subsequent procedure was 0.40 if the child developed it on the first procedure, 0.30 if he did not; this difference was not significant. The incidence of desaturation below 90% with severe respiratory compliance events was 0.20; the incidence of a 30% drop in EtCO2 was 0.34. No morbidity, no extended recovery, and no admissions were associated with intraoperative severe respiratory compliance events. We found no correlation between history, age, sex, weight or allergies, and intraoperative severe respiratory compliance events., Conclusions: Here, most patients experienced a severe respiratory compliance event during at least one of their procedures. Overall incidence was 29% and was more likely on subsequent procedures. A severe respiratory compliance event at the initial procedure was poorly predictive of its occurrence on subsequent procedures. No morbidity was associated with intraoperative severe respiratory compliance events., (© 2015 John Wiley & Sons Ltd.)

In this work we analyze electro-corticography (ECoG) recordings in human subjects during induction of anesthesia with propofol. We hypothesize that the decrease in responsiveness that defines the anesthetized state is concomitant with the stabilization of neuronal dynamics. To test this hypothesis, we performed a moving vector autoregressive analysis and quantified stability of neuronal dynamics using eigenmode decomposition of the autoregressive matrices, independently fitted to short sliding temporal windows. Consistent with the hypothesis we show that while the subject is awake, many modes of neuronal activity oscillations are found at the edge of instability. As the subject becomes anesthetized, we observe statistically significant increase in the stability of neuronal dynamics, most prominently observed for high frequency oscillations. Stabilization was not observed in phase randomized surrogates constructed to preserve the spectral signatures of each channel of neuronal activity. Thus, stability analysis offers a novel way of quantifying changes in neuronal activity that characterize loss of consciousness induced by general anesthetics.

Objective: Post-operative delirium is associated with pre-operative cognitive difficulties and diminished functional independence, both of which suggest that brain pathology may be present in affected individuals prior to surgery. Currently, there are few studies that have examined imaging correlates of post-operative delirium. To our knowledge, none have examined the association of delirium with existing structural pathology in pre-operative cancer patients. Here, we present a novel, retrospective strategy to assess pre-operative structural brain pathology and its association with post-operative delirium. Standard of care structural magnetic resonance imaging (MRIs) from a cohort of surgical candidates prior to surgery were analyzed for white matter hyperintensities and cerebral atrophy., Methods: We identified 23 non-small cell lung cancer patients with no evidence of metastases in the brain pre-operatively, through retrospective chart review, who met criteria for post-operative delirium within 4 days of surgery. 24 age- and gender-matched control subjects were identified for comparison to the delirium sample. T1 and fluid-attenuated inversion recovery sequences were collected from standard of care pre-operative MRI screening and assessed for white matter pathology and atrophy., Results: We found significant differences in white matter pathology between groups with the delirium group exhibiting significantly greater white matter pathology than the non-delirium group. Measure of cerebral atrophy demonstrated no significant difference between the delirium and non-delirium group., Conclusions: In this preliminary study utilizing standard of care pre-operative brain MRIs for assessment of structural risk factors to delirium, we found white matter pathology to be a significant risk factor in post-operative delirium. Limitations and implications for further investigation are discussed., (Copyright © 2013 John Wiley & Sons, Ltd.)

Global surgery initiatives increasingly are focused on strengthening education and local health care systems to build surgical capacity. The goal of this education project was to support local health care providers in augmenting the surgical curriculum at a new medical school, thus promoting long-term local goals and involvement. Working with local surgeons, residents, and medical and assistant medical officer students, we identified the most common surgical conditions presenting to Weill Bugando Medical Centre in Mwanza, Tanzania, and the areas of greatest need in surgical education. We developed an 8-week teaching schedule for undergraduate students and an electronic database of clinical surgery topics. In addition, we started teaching basic surgical skills in the operating theatre, bridging to an official and recurring workshop through a supporting international surgery organization. The medical and assistant medical officer students reported increased satisfaction with their clinical surgery rotations and mastery of key educational subjects. The initiation of an Essential Surgical Skills workshop through the Canadian Network for International Surgery showed students had improved comfort with basic surgical techniques. Short-term surgical missions may appear to fill a void in the shortage of health care in the developing world. However, we conclude that global health resources are more appropriately used through projects giving ownership to local providers and promoting education as a foundation of development. This results in better coordination among local and visiting providers and greater impact on education and long-term growth of health care capacity.

Background: Intravenous anesthetics have marked effects on memory function, even at subclinical concentrations. Fundamental questions remain in characterizing anesthetic amnesia and identifying affected system-level processes. The authors applied a mathematical model to evaluate time-domain components of anesthetic amnesia in human subjects., Methods: Sixty-one volunteers were randomized to receive propofol (n = 12), thiopental (n = 13), midazolam (n = 12), dexmedetomidine (n = 12), or placebo (n = 12). With drug present, subjects encoded pictures into memory using a 375-item continuous recognition task, with subsequent recognition later probed with drug absent. Memory function was sampled at up to 163 time points and modeled over the time domain using a two-parameter, first-order negative power function. The parietal event-related P2-N2 complex was derived from electroencephalography, and arousal was repeatedly sampled. Each drug was evaluated at two concentrations., Results: The negative power function consistently described the course of amnesia (mean R = 0.854), but there were marked differences between drugs in the modulation of individual components (P < 0.0001). Initial memory strength was a function of arousal (P = 0.005), whereas subsequent decay was related to the reaction time (P < 0.0001) and the P2-N2 complex (P = 0.007/0.002 for discrete components)., Conclusions: In humans, the amnesia caused by multiple intravenous anesthetic drugs is characterized by arousal-related effects on initial trace strength, and a subsequent decay predicted by attenuation of the P2-N2 complex at encoding. The authors propose that the failure of normal memory consolidation follows drug-induced disruption of interregional synchrony critical for neuronal plasticity and discuss their findings in the framework of memory systems theory.

Background: Emotional information has the ability to alter the formation and strength of a memory ('memory modulation'). Memory modulation by negative emotion is mediated by the amygdala. It is not known how gamma aminobutyric acid (GABA)ergic drugs affect the processes involved in memory modulation. This study investigates whether memory for negative emotional stimuli is more refractory to the effects of GABAergic drugs., Methods: Eighty-three healthy volunteers were shown a randomized sequence of 60 visual stimuli consisting of negative, positive and neutral emotive pictures, while receiving a controlled infusion of thiopental (n=31), propofol (n=31), dexmedetomidine (n=10) or placebo (n=11). After a 5 h retention interval, when drug concentration was negligible, subjects performed a recognition task with 'old' pictures randomly mixed with 'new' pictures. Drug effect was calculated as the proportionate reduction in recognition for images of each emotional valence., Results: Forty-eight subjects were included in a within-subject logistic dose-response model analysis. In the thiopental group there was a smaller drug effect seen for negative vs positive images (proportional memory reduction from baseline 0.27 (SD 0.20) vs 0.56 (0.25), P<0.001, n=20 included in analysis). A similar trend was seen in the propofol group (0.25 (0.28) vs 0.54 (0.30), n=10), but this did not attain statistical significance. No trend was seen in the dexmedetomidine group (0.33 (0.26) vs 0.24 (0.22), n=7)., Conclusions: Over a specific dose range of thiopental (target serum concentration 2-7 micro g ml(-1)), impairment of explicit memory for images with negative emotional valence is less than that for images with positive emotional valence. There is a strong possibility that propofol (target serum concentration 0.3-2.4 micro g ml(-1)) causes a similar effect. Modulation of visual memory by negative emotional content continues at sub-anaesthetic concentrations of GABAergic drugs associated with explicit memory impairment.

Context: Surgical site infection (SSI) in the general surgical population is a significant public health issue. The use of a high fractional inspired concentration of oxygen (FIO2) during the perioperative period has been reported to be of benefit in selected patients, but its role as a routine intervention has not been investigated., Objective: To determine whether the routine use of high FIO2 during the perioperative period alters the incidence of SSI in a general surgical population., Design, Setting, and Patients: Double-blind, randomized controlled trial conducted between September 2001 and May 2003 at a large university hospital in metropolitan New York City of 165 patients undergoing major intra-abdominal surgical procedures under general anesthesia., Interventions: Patients were randomly assigned to receive either 80% oxygen (FIO2 of 0.80) or 35% oxygen (FIO2 of 0.35) during surgery and for the first 2 hours after surgery., Main Outcome Measures: Presence of clinically significant SSI in the first 14 days after surgery, as determined by clinical assessment, a management change, and at least 3 prospectively defined objective criteria., Results: The study groups were closely matched in a large number of clinical variables. The overall incidence of SSI was 18.1%. In an intention-to-treat analysis, the incidence of infection was significantly higher in the group receiving FIO2 of 0.80 than in the group with FIO2 of 0.35 (25.0% vs 11.3%; P =.02). FIO2 remained a significant predictor of SSI (P =.03) in multivariate regression analysis. Patients who developed SSI had a significantly longer length of hospitalization after surgery (mean [SD], 13.3 [9.9] vs 6.0 [4.2] days; P<.001)., Conclusions: The routine use of high perioperative FIO2 in a general surgical population does not reduce the overall incidence of SSI and may have predominantly deleterious effects. General surgical patients should continue to receive oxygen with cardiorespiratory physiology as the principal determinant.