31 de agosto de 2012

Artigo recomendado: Coffee Drinking and Mortality

Scott K. Aberegg, M.D., M.P.H.

n engl j med 367;6 nejm.org august 9, 2012

To the Editor: Freedman et al. (May 17 issue) report the results of a widely publicized study of the association between coffee consumption and mortality. Several limitations and alternative explanations of their findings deserve consideration. The biologic plausibility of a reduction in mortality associated with coffee consumption is inadequately explicated. This is especially noteworthy because coffee consumption appeared to reduce the rate of death from accidents and injuries. In essence, this is a positive result on a negative control embedded within the study, and it undermines the study’s main findings. People frequently drink coffee at work (the proverbial “coffee break”), and the findings of this study could be due to a “healthy worker” effect not captured by other covariates, such as educational attainment and health status. The inclusion of relevant covariates is fraught with difficulty when a plausible mechanism supporting the main study findings is not apparent. The simplest explanation for the aggregate findings seems to be the most likely — in this case, residual confounding from unmeasured behaviors associated with coffee consumption that protect against everything, including accidents and injuries.

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28 de agosto de 2012

Artigo recomendado: Does Rotational Thromboelastometry (ROTEM) Improve Prediction of Bleeding After Cardiac Surgery?

Lee GC et al. – The results suggest that Rotational thromboelastometry (ROTEM) data do not substantially improve a model's ability to predict chest tube drainage, beyond frequently used clinical and laboratory parameters. Although several ROTEM parameters were individually associated with chest tube output (CTO), they did not significantly improve goodness of fit when added to statistical models comprising only clinical and routine laboratory parameters. ROTEM does not seem to improve prediction of chest tube drainage after cardiac surgery involving CPB, although its use in guiding transfusion during cardiac surgery remains to be determined.

Anesthesia & Analgesia, 08/22/2012  Clinical Article

  • Three hundred twenty-one patients undergoing cardiac surgery involving CPB were enrolled.
  • Patient data were obtained from medical records, including chest tube output (CTO) from post-CPB through the first 8 postoperative hours.
  • Perioperative and postoperative blood samples were collected for ROTEM analysis.
  • Three measures of CTO were used as the primary end points for assessing coagulopathy: continuous CTO; CTO dichotomized at 600mL (75th percentile); and CTO dichotomized at 910mL (90th percentile).
  • Clinical and hematological variables, excluding ROTEM data, that were significantly correlated (P < 0.05) with continuous CTO were included in a stepwise regression model (model 1).
  • An additional model that contained ROTEM variables in addition to the variables from model 1 was created (model 2).
  • Significance in subsequent analyses was declared at P < 0.0167 to account for the 3 CTO end points.
  • Net reclassification index was used to assess overall value of ROTEM data.

  • For continuous CTO, ROTEM variables improved the model's predictive ability (P < 0.0001).
  • For CTO dichotomized at 600mL (75th percentile), ROTEM did not improve the area under the receiver operating characteristic curve (AUC) (P = 0.03).
  • Similarly, for CTO dichotomized at 910mL (90th percentile), ROTEM did not improve the AUC (P = 0.23).
  • Net reclassification index similarly indicated that ROTEM results did not improve overall classification of patients (P = 0.12 for CTO ≥ 600mL; P=0.08 for CTO ≥ 910mL).

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24 de agosto de 2012

Artigo recomendado: Who Is at Risk for Postdischarge Nausea and Vomiting after Ambulatory Surgery?

Christian C. Apfel, Beverly K. Philip, Ozlem S. Cakmakkaya, Ashley Shilling, Yun-Ying Shi, John B. Leslie, Martin Allard, Alparslan Turan, Pamela Windle, Jan Odom-Forren, Vallire D. Hooper, Oliver C. Radke, Joseph Ruiz, Anthony Kovac

Anesthesiology 2012; 117:475– 86 476 Apfel et al.


Background: About one in four patients suffers from postoperative nausea and vomiting. Fortunately, risk scores have been developed to better manage this outcome in hospitalized patients, but there is currently no risk score for postdischarge nausea and vomiting (PDNV) in ambulatory surgical patients.

Methods: We conducted a prospective multicenter study of 2,170 adults undergoing general anesthesia at ambulatory surgery centers in the United States from 2007 to 2008. PDNV was assessed from discharge until the end of the second postoperative day. Logistic regression analysis was applied to a development dataset and the area under the receiver operating characteristic curve was calculated in a validation dataset.

Results: The overall incidence of PDNV was 37%. Logistic regression analysis of the development dataset (n=1,913) identified five independent predictors (odds ratio; 95% CI): female gender (1.54; 1.22 to 1.94), age less than 50 yr (2.17; 1.75 to 2.69), history of nausea and/or vomiting after previous anesthesia (1.50; 1.19 to 1.88), opioid administration in the postanesthesia care unit (1.93; 1.53 to 2.43), and nausea in the postanesthesia care unit (3.14; 2.44–4.04). In the validation dataset (n 257), zero, one, two, three, four, and five of these factors were associated with a PDNV incidence of 7%, 20%, 28%, 53%, 60%, and 89%, respectively, and an area under the receiver operating characteristic curve of 0.72 (0.69 to 0.73).

Conclusions: PDNV affects a substantial number of patients after ambulatory surgery. We developed and validated a simplified risk score to identify patients who would benefit from long-acting prophylactic antiemetics at discharge from the ambulatory care center.

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20 de agosto de 2012

Artigo: Volatile Anesthetics Reduce Invasion of Colorectal Cancer Cells through Down-regulation of Matrix Metalloproteinase-9

Björn Müller-Edenborn, Birgit Roth-Z’graggen, Kamila Bartnicka, Alain Borgeat, Alexandra Hoos, Lubor Borsig, Beatrice Beck-Schimmer

Anesthesiology, V 117 • No 2 293 August 2012

Background: Invasion of extracellular matrix is a hallmark of malignant tumors. Clamping maneuvers during cancer surgery reduce blood loss, but trigger reperfusion injury (RI). RI increases cancer recurrence in the reperfused organ through up-regulation of matrix metalloproteinase-9 (MMP-9). Interleukin-8 is an important cytokine in RI promoting accumulation of neutrophils, a major source of MMP-9. volatile anesthetics were demonstrated to reduce RI. We hypothesized that these anesthetics might attenuate MMP-9 up-regulation and consequently tumor cell invasion in RI.

Methods: Isolated human neutrophils (n=6) were preconditioned with sevoflurane or desflurane, followed by stimulation with interleukin-8, phorbol myristate acetate, or chemokine CXC-ligand 1 (CXCL1) to differentiate intracellular pathways. MMP-9 release and activity were quantified by enzyme-linked immunosorbent assay and zymography, respectively. CXC-receptor-2 (CXCR2) expression and phosphorylation of extracellular signal-regulated kinases 1/2 were assessed by flow cytometry. The impact of MMP-9 on the invasion of neutrophils and MC-38 colon cancer cells was assessed using Matrigel-coated filters (n=6).

Results: Preconditioning reduced interleukin-8-induced MMP-9-release by 41% (±13, 5%, sevoflurane) and 40% (±13%, desflurane). This was also evident following stimulation of CXCR2 with CXCL1. No impact on phosphorylation of extracellular signal-regulated kinases 1/2 and MMP-9 release was observed with receptor-independent stimulation of protein kinase C with phorbol myristate acetate. Preconditioning reduced transmigration of neutrophils and MC-38 tumor cells to baseline levels.

Discussion: Volatile anesthetics impair neutrophil MMP-9 release and interfere with pathways downstream of CXCR2, but upstream of protein kinase C. Through down-regulation of MMP-9, volatile anesthetics decrease Matrigel breakdown and reduce subsequent migration of cancer cells in vitro.

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17 de agosto de 2012

Case Scenario: Severe Emergence Agitation after Myringotomy in a 3-yr-old Child

Souhayl Dahmani, Jean Mantz, Francis Veyckemans

Anesthesiology, V 117, No 2 - August 2012

Emergence agitation (EA) in children, also called postanesthetic or postoperative delirium, agitation, or excitement in children, is a specific pediatric postoperative complication. Its reported incidence ranges from 2 to 80%.1,2 This explains in part why it is usually considered as a part of the “normal” emergence process by many pediatric anesthesiologists. However, for those who episodically care for pediatric patients in the postanesthesia period (both medical and nursing staff), it may represent a significant source of anxiety and disappointment. Moreover, parents of children experiencing this complication might be terrorized by this event, and the motor agitation accompanying EA may cause harm to the child, such as loss of IV line, removal of surgical dressing, and so on.

In the current case scenario, we shall focus on the description of emergence agitation and the associated risk factors, prevention, and treatment. We will also try to establish a relation between EA and other postoperative behavioral issues observed in children, such as postoperative maladaptive behaviors.

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13 de agosto de 2012

Artigo recomendado: Complex regional pain syndrome type I: incidence and prevalence in Olmsted county, a population-based study

Paola Sandroni, Lisa M Benrud-Larson, Robyn L McClelland, Phillip A Low

The Journal of Pain Volume 103, Issue 1 , Pages 199-207, May 2003


The objective of this study is to undertake a population based study on the incidence, prevalence, natural history, and response to treatment of complex regional pain syndrome (CRPS). All Mayo Clinic and Olmsted Medical Group medical records with codes for reflex sympathetic dystrophy (RSD), CRPS, and compatible diagnoses in the period 1989–1999 were reviewed as part of the Rochester Epidemiology Project. We used IASP criteria for CRPS. The study population was in the Olmsted County, Minnesota (1990 population, 106,470). The main outcome measures were CRPS I incidence, prevalence, and outcome. Seventy-four cases of CRPS I were identified, resulting in an incidence rate of 5.46 per 100,000 person years at risk, and a period prevalence of 20.57 per 100,000. Female:male ratio was 4:1, with a median age of 46 years at onset. Upper limb was affected twice as commonly as lower limb. All cases reported an antecedent event and fracture was the most common trigger (46%). Excellent concordance was found between symptoms and signs and vasomotor symptoms were the most commonly present. Three phase bone scan and autonomic testing diagnosed the condition in >80% of cases. Seventy-four percent of patients underwent resolution, often spontaneously. CRPS I is of low prevalence, more commonly affects women than men, the upper more than the lower extremity, and three out of four cases undergo resolution. These results suggest that invasive treatment of CRPS may not be warranted in the majority of cases.

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9 de agosto de 2012

Brain Stimulation in the Treatment of Chronic Neuropathic and Non-Cancerous Pain

Ela B. Plow, Alvaro Pascual-Leone, Andre Machado

The Journal of Pain Volume 13, Issue 5 , Pages 411-424, May 2012

Chronic neuropathic pain is one of the most prevalent and debilitating disorders. Conventional medical management, however, remains frustrating for both patients and clinicians owing to poor specificity of pharmacotherapy, delayed onset of analgesia and extensive side effects. Neuromodulation presents as a promising alternative, or at least an adjunct, as it is more specific in inducing analgesia without associated risks of pharmacotherapy. Here, we discuss common clinical and investigational methods of neuromodulation. Compared to clinical spinal cord stimulation (SCS), investigational techniques of cerebral neuromodulation, both invasive (deep brain stimulation [DBS] and motor cortical stimulation [MCS]) and noninvasive (repetitive transcranial magnetic stimulation [rTMS] and transcranial direct current stimulation [tDCS]), may be more advantageous. By adaptively targeting the multidimensional experience of pain, subtended by integrative pain circuitry in the brain, including somatosensory and thalamocortical, limbic and cognitive, cerebral methods may modulate the sensory-discriminative, affective-emotional and evaluative-cognitive spheres of the pain neuromatrix. Despite promise, the current state of results alludes to the possibility that cerebral neuromodulation has thus far not been effective in producing analgesia as intended in patients with chronic pain disorders. These techniques, thus, remain investigational and off-label. We discuss issues implicated in inadequate efficacy, variability of responsiveness, and poor retention of benefit, while recommending design and conceptual refinements for future trials of cerebral neuromodulation in management of chronic neuropathic pain.

This critical review focuses on factors contributing to poor therapeutic utility of invasive and noninvasive brain stimulation in the treatment of chronic neuropathic and pain of noncancerous origin. Through key clinical trial design and conceptual refinements, retention and consistency of response may be improved, potentially facilitating the widespread clinical applicability of such approaches.

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7 de agosto de 2012

Innate Immune Dysfunction in Trauma Patients - From Pathophysiology to Treatmentg

Karim Asehnoune, Antoine Roquilly, Edward Abraham

Anesthesiology, V 117 - No. 2 - August 2012

Severe trauma is a leading cause of death in young healthy individuals. Despite significant advances in the fields of resuscitation and modern intensive care medicine, infection remains the most frequent cause of poor outcome in severely injured patients. Osborn et al. have demonstrated that sepsis, and particularly ventilator-associated pneumonia, were associated with a significant increase in mortality after severe trauma.1 In the same study, septic trauma patients also presented an increased intensive care unit length of stay as compared with patients without infection (21.8 vs. 4.7 days, P < 0.001). A marked depression of cell-mediated immune function, so-called “posttraumatic immunosupression", occurs after trauma and appears to contribute to poor clinical outcome.

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3 de agosto de 2012

Accuracy of Ultrasound-guided Nerve Blocks of the Cervical Zygapophysial Joints

Andreas Siegenthaler, Sabine Mlekusch, Sven Trelle, Juerg Schliessbach, Michele Curatolo, Eichenberger

Anesthesiology, V 117 - No 2 - August 2012

Background: Cervical zygapophysial joint nerve blocks typically are performed with fluoroscopic needle guidance. Descriptions of ultrasound-guided block of these nerves are available, but only one small study compared ultrasound with fluoroscopy, and only for the third occipital nerve. To evaluate the potential usefulness of ultrasound-guidance in clinical practice, studies that determine the accuracy of this technique using a validated control are essential. The aim of this study was to determine the accuracy of ultrasoundguided nerve blocks of the cervical zygapophysial joints using fluoroscopy as control.

Methods: Sixty volunteers were studied. Ultrasound-imaging was used to place the needle to the bony target of cervical zygapophysial joint nerve blocks. The levels of needle placement were determined randomly (three levels per volunteer). After ultrasound-guided needle placement and application of 0.2 ml contrast dye, fluoroscopic imaging was performed for later evaluation by a blinded pain physician and considered as gold standard. Raw agreement, chance-corrected agreement, and chance-independent agreement between the ultrasound-guided placement and the assessment using fluoroscopy were calculated to quantify accuracy.

Results: One hundred eighty needles were placed in 60 volunteers. Raw agreement was 87% (95% CI 81–91%), was 0.74 (0.64–0.83), and 0.99 (0.99–0.99). Accuracy varied significantly between the different cervical nerves: it was low for the C7 medial branch, whereas all other levels showed very good accuracy.

Conclusions: Ultrasound-imaging is an accurate technique for performing cervical zygapophysial joint nerve blocks in volunteers, except for the medial branch blocks of C7.

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