Efficacy of a propofol bolus against placebo to prevent cough at emergence from general anesthesia with desflurane: a randomized controlled trial.

PURPOSE: Emergence from anesthesia is a critical period and cough can result in adverse effects. Propofol inhibits airway reflexes and when infused it reduces cough more than inhalation anesthesia does. We evaluated the effect of a propofol bolus given at emergence on the incidence of coughing following a desflurane-based anesthesia. METHODS: One hundred and fifty-four patients scheduled for elective surgery were prospectively randomized to propofol (0.5 mg·kg-1) or normal saline (NS) administered at the end of the surgery at 1 minimum alveolar concentration (MAC) of desflurane. A "no touch" emergence technique was used until extubation. The primary outcome was the incidence of cough at the discontinuation of desflurane (T0) and reaching a MAC adjusted for age (MACage) of 0.15. Secondary outcomes included incidence and severity of cough until five minutes postextubation (T0-T5), time to extubation, nausea and vomiting, sedation, hemodynamic variations, postoperative hypoventilation, hypoxemia, and sore throat. RESULTS: We could not draw inferences on the incidence of cough between T0 and MACage of 0.15 because only 27/68 (40%) patients in the NS group and 13/73 (18%) patients in the propofol group regained consciousness before reaching a MACage of 0.15. There were no significant differences between the groups in coughing incidence and severity between T0 and T5 (NS group, 57/68 [84%] vs propofol group, 70/73 [96%] ). The mean time to extubation in the propofol group was prolonged by 3 min 27 sec (95% confidence interval, 1 min 7 sec to 4 min 47 sec; P < 0.001) and more vasopressors were used at emergence (P = 0.02). The incidence of respiratory complications, nausea and vomiting, agitation, and sedation were not different between groups. CONCLUSION: In the present trial, a propofol bolus administered at emergence did not reduce the incidence of cough occurring between T0 and T5 following a desflurane-based general anesthesia compared with placebo. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02932397); registered 13 October 2016.

RéSUMé: OBJECTIF: L'émergence de l'anesthésie est une période critique et la toux peut entraîner des effets indésirables. Le propofol inhibe les réflexes des voies aériennes et, lorsqu'il est perfusé, il est plus efficace pour réduire la toux que l'anesthésie inhalée. Nous avons évalué l'effet d'un bolus de propofol administré à l'émergence sur l'incidence de toux après une anesthésie à base de desflurane. MéTHODE: Cent cinquante-quatre patients devant bénéficier d'une chirurgie non urgente ont été randomisés prospectivement à recevoir du propofol (0,5 mg·kg−1) ou une solution physiologique de sérum salé (NS) administrée à la fin de la chirurgie lorsque la concentration alvéolaire minimale (MAC) de desflurane était de 1. Une technique d'émergence « sans contact ¼ a été utilisée jusqu'à l'extubation. Le critère d'évaluation principal était l'incidence de toux à l'arrêt du desflurane (T0) et à l'atteinte d'une MAC ajustée en fonction de l'âge (MACâge) de 0,15. Les critères d'évaluation secondaires comprenaient l'incidence et la gravité de la toux jusqu'à cinq minutes après l'extubation (T0-T5), le délai d'extubation, les nausées et vomissements, la sédation, les variations hémodynamiques, l'hypoventilation postopératoire, l'hypoxémie et les maux de gorge. RéSULTATS: Nous n'avons pas pu tirer de conclusions sur l'incidence de toux entre T0 et à une MACâge de 0,15 parce que seulement 27/68 (40 %) patients du groupe NS et 13/73 (18 %) patients du groupe propofol ont repris conscience avant d'atteindre une MACâge de 0,15. Il n'y avait aucune différence significative entre les groupes dans l'incidence et la gravité de la toux entre T0 et T5 (groupe NS, 57/68 [84 %] vs groupe propofol, 70/73 [96 %]). Le temps moyen d'extubation dans le groupe propofol a été prolongé de 3 min 27 sec (intervalle de confiance à 95 %, 1 min 7 sec à 4 min 47 sec; P < 0,001) et une plus grande quantité de vasopresseurs a été utilisée à l'émergence (P = 0,02). L'incidence de complications respiratoires, de nausées et vomissements, d'agitation, et de sédation n'était pas différente entre les groupes. CONCLUSION: Dans la présente étude, un bolus de propofol administré à l'émergence n'a pas réduit l'incidence de toux survenant entre T0 et T5 après une anesthésie générale à base de desflurane par rapport au placebo. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov (NCT02932397); enregistrée le 13 octobre 2016.

The impact of a perceptual learning module on novices' ability to visually estimate left ventricular ejection fraction by transesophageal echocardiography: a randomized controlled study.

PURPOSE: Echocardiography is a difficult tool to master. Competency requires the supervised interpretation of hundreds of exams. Perceptual learning modules (PLMs) are novel learning tools that aim to speed up this learning process by enabling learners to go online and interpret numerous clinical images, followed systematically by expert feedback. We developed and tested a PLM aimed at improving novices' ability to quickly visually estimate left ventricular ejection fraction (LVEF) on transesophageal echocardiography images, a critical skill in acute care. We hypothesized that using the PLM would improve the accuracy and the speed of learners' estimations. METHODS: Learners without echocardiography experience were randomly assigned to a group that used the 96-case PLM (n = 26) or a control group (n = 26) that did not. Both groups took a pre-test and an immediate post-test that measured the accuracy of their visual estimations during a first session. At six months, participants also completed a delayed post-test. RESULTS: In the immediate post-test, the PLM group showed significantly better accuracy than the control group (median absolute estimation error 6.1 vs 9.0; difference 95% CI, 1.0 to 4.6; P < 0.001). Nevertheless, at six months, estimation errors were similar in both groups (median absolute estimation error 10.0 vs 10.0; difference 95% CI, -1.3 to 2.1; P = 0.27). CONCLUSIONS: Participation in a short online PLM significantly improved novices' short-term ability to accurately estimate LVEF visually, compared with controls. The effect was not sustained at six months. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03245567); registered 7 August 2017.

RéSUMé: OBJECTIF: L'échocardiographie est un outil difficile à maîtriser. Afin d'acquérir cette compétence, l'interprétation supervisée de centaines d'examens est nécessaire. Les modules d'apprentissage perceptuel (MAP) sont des outils d'apprentissage innovants qui visent à accélérer ce processus d'apprentissage en permettant aux apprenants d'aller en ligne et d'interpréter de nombreuses images cliniques, lesquelles sont systématiquement suivies par des rétroactions d'experts. Nous avons mis au point et testé un MAP visant à améliorer la capacité des nouveaux apprenants à rapidement estimer visuellement la fraction d'éjection ventriculaire gauche (FEVG) sur des images d'échocardiographie transœsophagienne, une compétence critique dans les soins aigus. Nous avons émis l'hypothèse que l'utilisation du MAP améliorerait la précision et la rapidité des estimations des apprenants. MéTHODE: Les apprenants sans expérience de lecture d'échocardiographie ont été aléatoirement alloués à un groupe qui a utilisé le MAP de 96 cas (n = 26) ou à un groupe témoin (n = 26) qui ne l'a pas utilisé. Les deux groupes ont passé un prétest et un post-test immédiat qui ont mesuré l'exactitude de leurs estimations visuelles au cours d'une première séance. Six mois plus tard, les participants ont également passé un autre post-test retardé. RéSULTATS: Dans le post-test immédiat, le groupe MAP a démontré une précision significativement meilleure que le groupe témoin (erreur d'estimation absolue médiane, 6,1 vs 9,0; différence de l'IC 95 %, 1,0 à 4,6; P < 0,001). Néanmoins, à six mois, les erreurs d'estimation étaient similaires dans les deux groupes (erreur d'estimation absolue médiane, 10,0 vs 10,0; différence de l'IC 95 %, -1,3 à 2,1; P = 0,27). CONCLUSION: La participation à un bref MAP en ligne a considérablement amélioré la capacité à court terme des nouveaux apprenants à estimer visuellement et avec précision la FEVG, par rapport à un groupe témoin. L'effet n'était pas maintenu à six mois. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT03245567); enregistrée le 7 août 2017.

Superior Proton Exchange Membrane Fuel Cell (PEMFC) Performance Using Short-Side-Chain Perfluorosulfonic Acid (PFSA) Membrane and Ionomer.

Optimization of the ionomer materials in catalyst layers (CLs) which sometimes is overlooked has been equally crucial as selection of the membranes in membrane electrode assembly (MEA) for achieving a superior performance in proton exchange membrane fuel cells (PEMFCs). Four combinations of the MEAs composed of short-side-chain (SSC) and long-side-chain (LSC) perfluorosulfonic acid (PFSA) polymers as membrane and ionomer materials have been prepared and tested under various temperatures and humidity conditions, aiming to investigate the effects of different side chain polymer in membranes and CLs on fuel cell performance. It is discovered that SSC PFSA polymer used as membrane and ionomer in CL yields better fuel cell performance than LSC PFSA polymer, especially at high temperature and low RH conditions. The MEA with the SSC PFSA employed both as a membrane and as an ionomer in cathode CL demonstrates the best cell performance amongst the investigated MEAs. Furthermore, various electrochemical diagnoses have been applied to fundamentally understand the contributions of the different resistances to the overall cell performance. It is illustrated that the charge transfer resistance (Rct) made the greatest contribution to the overall cell resistance and then membrane resistance (Rm), implying that the use of the advanced ionomer in CL could lead to more noticeable improvement in cell performance than only the substitution as the membrane.

Effects of 1, 2, 4-Triazole Additive on PEM Fuel Cell Conditioning.

Melt processing is one of the essential technologies for the mass production of polymer electrolyte membranes (PEM) at low cost. Azoles have been widely used in PEM to improve their conductivity at a relatively low humidity and recently as bifunctional additives in a melt blowing processing for PEM mass production. In this work, we attempted to assess the effect of 1, 2, 4-triazole additive in membranes and in catalyst layers on PEM fuel cell conditioning. Various characterization tools including electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and conditioning with constant current were applied to diagnose the temporary electrochemical reaction effect and the permanent performance loss caused by the triazole additives. It was found that triazole additives in membranes could migrate into the catalyst layers and significantly affect the open circuit voltage (OCV) and the conditioning. The effect could be partially or completely removed/cleaned either through longer conditioning time or via CV cycling, which depends on the amount of additives remaining in the membrane. The findings provide valuable scientific insights on the relevance of post treatment steps during membrane production and overcoming fuel cell contamination issues due to residual additive in the membranes and understanding the quality control needed for fuel cell membranes by melt blowing processing.

Effects of positive end-expiratory pressure/recruitment manoeuvres compared with zero end-expiratory pressure on atelectasis during open gynaecological surgery as assessed by ultrasonography: a randomised controlled trial.

BACKGROUND: During general anaesthesia, most patients develop atelectasis, which promotes postoperative pulmonary complications. RCTs that investigated perioperative lung protection have failed to reduce postoperative pulmonary complications consistently. Ultrasound imaging could help confirm the effects of different protective ventilatory strategies, but this has not been tested in trials. The objective of this study was to use ultrasonography to evaluate whether lung-protective ventilation measures reduce perioperative atelectasis. METHODS: We conducted a prospective, randomised patient- and assessor-blinded controlled trial in women undergoing open gynaecological surgery. Subjects were randomised to either lung protection or zero end-expiratory pressure (ZEEP; with no recruitment manoeuvres [RMs]). Lung protection entailed PEEP (7 cm H2O) and RMs every 30 min. Lung ultrasonography was undertaken at five predefined time points. The primary outcome was the difference in lung ultrasonography score (LUS) between groups before emergence; a lower LUS indicates better lung aeration. RESULTS: We recruited 45 women (34-85 yr old). Women randomised to lung protection had lower mean (standard deviation) LUS before emergence (6.1 [3.7]), compared with women randomised to ZEEP (11.7 [3.9]; 95% confidence interval for the difference between group means [-7.9 to -3.2]; P<0.0001). This difference did not persist after extubation, with similar mean LUSs in women who had received intraoperative lung protection (7.0 [4.1]), compared with women randomised to receive ZEEP (7.7 [3.1]). CONCLUSIONS: As assessed by lung ultrasonography, intraoperative PEEP/RMs decreased aeration loss during general anaesthesia. However, similar degrees of aeration loss were observed after tracheal extubation regardless of intraoperative ventilatory strategy. CLINICAL TRIAL REGISTRATION: NCT02055807.

The relative weight of ontogeny, topology and climate in the architectural development of three North American conifers.

Knowledge of plant architecture allows retrospective study of plant development, hence provides powerful tools, through modelling and simulation, to link this development with environmental constraints, and then predict its response to global change. The present study aims to determine some of the main endogenous and exogenous variables driving the architectural development of three North American conifers. We measured architectural traits retrospectively on the trunk, branches and twigs of whole tree crowns for each species: annual shoot length (ASL), needle length, branching patterns and reproduction organs (male and female). We fitted a partial least square (PLS) regression to explain each architectural trait with respect to topological, ontogenic and climatic variables. Results showed a significant weight of these three groups of variables for previous and current year, corresponding, respectively, to organogenesis and elongation. Topological and ontogenic variables had the greatest weight in models. Particularly, all architectural traits were strongly correlated with ASL. We highlighted a negative architectural response of two species to higher than average temperatures, whereas the third one took advantage of these higher temperatures to some degree. Tree architectural development weekly but significantly improved with higher precipitation. Our study underlines the strong weight of topology and ontogeny in tree growth patterns at twig and branch scales. The correlation between ASL and other tree architectural traits should be integrated into architectural development models. Climate variables are secondary in importance at the twig scale. However, interannual climate variations influence all axis categories and branching orders and therefore significantly impact crown development as a whole. This latter impact may increase with climate change, especially as climate affects architectural traits over at least 2 years, through organogenesis and elongation.

Drought timing and local climate determine the sensitivity of eastern temperate forests to drought.

Projected changes in temperature and drought regime are likely to reduce carbon (C) storage in forests, thereby amplifying rates of climate change. While such reductions are often presumed to be greatest in semi-arid forests that experience widespread tree mortality, the consequences of drought may also be important in temperate mesic forests of Eastern North America (ENA) if tree growth is significantly curtailed by drought. Investigations of the environmental conditions that determine drought sensitivity are critically needed to accurately predict ecosystem feedbacks to climate change. We matched site factors with the growth responses to drought of 10,753 trees across mesic forests of ENA, representing 24 species and 346 stands, to determine the broad-scale drivers of drought sensitivity for the dominant trees in ENA. Here we show that two factors-the timing of drought, and the atmospheric demand for water (i.e., local potential evapotranspiration; PET)-are stronger drivers of drought sensitivity than soil and stand characteristics. Drought-induced reductions in tree growth were greatest when the droughts occurred during early-season peaks in radial growth, especially for trees growing in the warmest, driest regions (i.e., highest PET). Further, mean species trait values (rooting depth and ψ50 ) were poor predictors of drought sensitivity, as intraspecific variation in sensitivity was equal to or greater than interspecific variation in 17 of 24 species. From a general circulation model ensemble, we find that future increases in early-season PET may exacerbate these effects, and potentially offset gains in C uptake and storage in ENA owing to other global change factors.

The Effect of Adductor Canal Block on Knee Extensor Muscle Strength 6 Weeks After Total Knee Arthroplasty: A Randomized, Controlled Trial.

BACKGROUND: Total knee arthroplasty (TKA) reduces knee extensor muscle strength (KES) in the operated limb for several months after the surgery. Immediately after TKA, compared to either inguinal femoral nerve block or placebo, adductor canal block (ACB) better preserves KES. Whether this short-term increase in KES is maintained several weeks after surgery remains unknown. We hypothesized that 48 hours of continuous ACB immediately after TKA would improve KES 6 weeks after TKA, compared to placebo. METHODS: Patients scheduled for primary unilateral TKA were randomized to receive either a continuous ACB (group ACB) or a sham block (group SHAM) for 48 hours after surgery. Primary outcome was the difference in maximal KES 6 weeks postoperatively, measured with a dynamometer during maximum voluntary isometric contraction. Secondary outcomes included postoperative day 1 (POD1) and day 2 (POD2) KES, pain scores at rest and peak effort, and opioid consumption; variation at 6 weeks of Knee Osteoarthritis Outcome Score, patient satisfaction, and length of hospital stay. RESULTS: Sixty-three subjects were randomized and 58 completed the study. Patients in group ACB had less pain at rest during POD1 and during peak effort on POD1 and POD2, consumed less opioids on POD1 and POD2, and had higher median KES on POD1. There was no significant difference between groups for median KES on POD2, variation of Knee Osteoarthritis Outcome Score, patient satisfaction, and length of stay. There was no difference between groups in median KES 6 weeks after surgery (52 Nm [31-89 Nm] for group ACB vs 47 Nm [30-78 Nm] for group SHAM, P= .147). CONCLUSIONS: Continuous ACB provides better analgesia and KES for 24-48 hours after surgery, but does not affect KES 6 weeks after TKA. Further research could evaluate whether standardized and optimized rehabilitation over the long term would allow early KES improvements with ACB to be maintained over a period of weeks or months.

Alkalinized Lidocaine Preloaded Endotracheal Tube Cuffs Reduce Emergence Cough After Brief Surgery: A Prospective Randomized Trial.

BACKGROUND: Alkalinized lidocaine in the endotracheal tube (ETT) cuff decreases the incidence of cough and throat pain on emergence after surgery lasting more than 2 hours. However, alkalinized lidocaine needs 60-120 minutes to cross the ETT cuff membrane; therefore, its usefulness in shorter duration surgery is unknown. This prospective double-blind randomized controlled trial tested the hypothesis that alkalinized lidocaine would reduce the incidence of emergence cough after surgeries lasting <120 minutes. METHODS: After local ethics board approval, American Society of Anesthesiologists I-III patients consented to be randomized into 1 of 2 groups receiving either alkalinized lidocaine (group AL) or saline (group S) to inflate the ETT cuff. Cuffs were prefilled >90 minutes before intubation with either 2 mL of 2% lidocaine and 8 mL of 8.4% bicarbonate (group AL) or 10 mL of normal saline (group S). Cuffs were emptied immediately before intubation. After intubation, either 2 mL of 2% lidocaine (AL) or 2 mL of saline (S) were injected into the cuff. Additional 8.4% bicarbonate (AL) or saline (S) was injected into the cuff until there was no air leak. Anesthesia was maintained using desflurane, rocuronium, and either fentanyl or sufentanil to maintain vital signs within 20% of baseline values. Opioids administered in prophylaxis of extubation cough were proscribed. A standardized "no touch" emergence technique was used. A blinded assessor noted any cough above 0.2 minimum alveolar concentration (MAC) of expired desflurane. At 0.2 MAC, once every 30 seconds, the patient was instructed to open his eyes and extubation occurred once a directed response was noted. RESULTS: A total of 213 patients were randomized and 100 patients in each group completed the experimental protocol. The incidence of extubation cough in group AL was 12%, significantly lower (1-sided P = .045) than the 22% incidence in group S. The 1-tailed risk ratio for cough in group AL was 0.55 (0-0.94, P = .045). Total amount of opioids administered (P = .194), ETT cuff preloading times (P = .259), and extubation times (P = .331) were not significantly different between groups. The average duration of surgery was 59 ± 28 minutes in group AL and 52 ± 29 minutes in group S (P = .057). CONCLUSIONS: Alkalinized lidocaine in the ETT cuff significantly decreased general anesthesia emergence cough after surgeries with an average duration of slightly <1 hour.

Lung Ultrasonography for the Assessment of Perioperative Atelectasis: A Pilot Feasibility Study.

BACKGROUND: Few diagnostic tools are available to anesthesiologists when confronted with intraoperative hypoxemia. Lung ultrasonography is a safe and accurate bedside imaging modality. The aim of this study was to evaluate the feasibility of lung ultrasonography during the perioperative period and assess its ability to detect intraoperative respiratory complications and oxygenation changes resulting from perioperative atelectasis. METHODS: In this prospective observational pilot study, 30 consecutive patients scheduled for laparoscopic surgery were recruited. Mechanical ventilation was standardized. Lung ultrasonography was performed at 5 predefined time points: before induction of general anesthesia (GA), after induction of GA, after pneumoperitoneum insufflation, on arrival in the recovery room, and before recovery room discharge. For each echographic examination, 12 pulmonary quadrants were imaged. From these, a semiquantitative score, the lung ultrasound (LUS) score, was calculated to assess lung aeration at each time point. RESULTS: Lung ultrasonography was possible in all patients. Changes in the LUS score between the postinduction period and arrival in the recovery room were correlated with changes in oxygenation (Spearman r = -0.43, P = .018). Induction of GA was associated with an increase in the LUS score, which gradually worsened at all time points until recovery room discharge. This increase was significantly worse in the basal and dependent lung zones. Lung ultrasonography helped in the detection of 2 capnothoraces, 1 endobronchial intubation, and 1 episode of subclinical pulmonary edema. CONCLUSIONS: Lung ultrasonography in the perioperative period is feasible, allows tracking of perioperative atelectasis, and facilitates the diagnosis of respiratory complications. The evolution of aeration loss correlates moderately with changes in oxygenation.

I-gel Versus LMA-Fastrach Supraglottic Airway for Flexible Bronchoscope-Guided Tracheal Intubation Using a Parker (GlideRite) Endotracheal Tube: A Randomized Controlled Trial.

BACKGROUND: The I-gel (IG) supraglottic airway device is a reliable way to establish an airway. Its large ventilation lumen allows for easy passage of an endotracheal tube. With the use of a flexible bronchoscope, the IG offers a good visualization of the laryngeal inlet. This prospective randomized study aims to compare the success rate of flexible bronchoscope-guided tracheal intubation using either the IG or the LMA-Fastrach (FT) laryngeal masks. METHODS: One hundred twenty patients requiring general anesthesia were randomized to 1 of the 2 study groups: IG or FT. After anesthesia induction, the assigned laryngeal mask was inserted to obtain adequate ventilation. We then proceeded to a flexible bronchoscope-guided intubation through the supraglottic device. Tracheal intubation and laryngeal mask insertion success rates were noted, as well as the time required for these manipulations. The view of the laryngeal inlet was graded for each intubation attempt. RESULTS: Sixty patients were assigned to each study group. The intubation success rates were similar between the IG and the FT groups (100 % vs 95.0 % at first attempt; P = 0.12). The times required for tracheal intubation were significantly lower in the IG group (30 ± 11 seconds vs 50 ± 21 seconds; P < 0.0001). Glottic visualization was better in the IG group, with a significantly higher percentage of grade 1 visualization (63.3% vs 3.3%; P < 0.0001) and a lower percentage of grade 3 visualization (1.7% vs 60.0%; P < 0.0001), than that in the FT group. CONCLUSIONS: The use of the IG supraglottic airway device as a conduit for flexible bronchoscope-guided tracheal intubation results in a success rate equivalent to the use of the LMA-FT. However, the IG allows for shorter intubation times and a better visualization of the glottic opening compared with the LMA-FT.

Impact of pregabalin on the occurrence of postthoracotomy pain syndrome: a randomized trial.

BACKGROUND: Postthoracotomy pain syndrome (PTPS) is a frequent cause of chronic postoperative pain. Pregabalin might reduce the incidence of chronic postoperative pain. The goal of this study was to evaluate the impact of perioperative pregabalin on the occurrence of PTPS, defined as any surgical site pain 3 months after surgery. METHODS: We conducted a randomized, placebo-controlled, double-blind trial in patients undergoing elective thoracotomy. Patients received either pregabalin 150 mg orally twice a day initiated 1 hour before thoracotomy and continued until 4 days after thoracotomy (10 doses total) or a placebo using the same protocol. All patients received preincision thoracic epidural analgesia. Postthoracotomy pain syndrome was evaluated using the Brief Pain Inventory questionnaire through a telephone interview. Secondary outcomes included evaluation of neuropathic characteristics through the Leeds Assessment of Neuropathic Symptoms and Signs questionnaire, analgesic use 3 months after surgery, and evaluation of acute postoperative pain and opioid consumption. RESULTS: One hundred fourteen patients were randomized, and 99 patients completed the study (placebo, n = 49; pregabalin, n = 50). Postthoracotomy pain syndrome occurred in 49 (49.5%) of 99 patients and more frequently in the pregabalin group (31/50 [62%] vs 18/49 [37%] in the placebo group, P = 0.01). However, among patients with PTPS, those in the pregabalin group required significantly less analgesics, reported less moderate to severe average pain, and presented significantly less neuropathic characteristics than patients in the placebo group 3 months after surgery. CONCLUSIONS: Pregabalin did not reduce the incidence of PTPS in this study. Future research on PTPS should focus on the impact of regional analgesia on central sensitization.

A comparison of two doses of mannitol on brain relaxation during supratentorial brain tumor craniotomy: a randomized trial.

BACKGROUND: Twenty percent mannitol is widely used to reduce brain bulk and facilitate the surgical approach in intracranial surgery. However, a dose-response relationship has not yet been established. In this study, we compared the effects of 0.7 and 1.4 g·kg(-1) mannitol on brain relaxation during elective supratentorial brain tumor surgery. METHODS: In this prospective, randomized, double-blind study, we enrolled 80 patients undergoing supratentorial craniotomy for tumor resection. Patients were assigned to receive 0.7 g·kg(-1) (group L) or 1.4 g·kg(-1) (group H) of 20% mannitol at surgical incision. Brain relaxation was assessed immediately after opening of the dura on a scale ranging from 1 to 4 (1 = perfectly relaxed, 2 = satisfactorily relaxed, 3 = firm brain, 4 = bulging brain). RESULTS: There was no significant difference between the 2 groups regarding age, sex, body mass index, and brain tumor localization or size. In group L 52.5% of patients and in group H 77.5% of patients presented a midline shift (P = 0.03). The median scores of brain relaxation (interquantile range) were 2.0 (1.75-3) and 2.0 (1-3) (P = 0.16 for patients in group L and H, respectively). We then used a proportional odds model to adjust for this unbalanced distribution and to assess the group effect (low-dose versus high-dose mannitol) on brain relaxation scores. When adjusted for the presence of midline shift, the use of a higher dose of mannitol resulted in an odds ratio of 2.5 (P = 0.03). This indicates that, considering the effect of a midline shift, the odds of having a 1-level improvement in relaxation score in patients who received a higher dose of mannitol (group H) was 2.5 times as large as the odds for the low-dose group. The odds ratio of 0.29 (P = 0.007) for the midline shift indicates that its occurrence was associated with a higher probability of a lower relaxation score, on average. CONCLUSION: In this study, we show that 1.4 g·kg(-1) of 20% mannitol results in equivalent brain relaxation scores as 0.7 g·kg(-1) in patients undergoing craniotomy for supratentorial brain tumor. When corrected for the presence of midline shift, this study reveals that patients in the high-dose group had significantly more chances of obtaining a better relaxation score compared with the lower-dose group.

Postoperative anemia does not impede functional outcome and quality of life early after hip and knee arthroplasties.

BACKGROUND: Clinicians have adopted a restrictive transfusion threshold (75-80 g/L) after major orthopedic surgery. Anemia may be associated with a decrease in postoperative vigor. We hypothesize that, in these patients, a threshold hemoglobin (Hb) concentration exists below which functional recovery and quality of life (QoL) become difficult. STUDY DESIGN AND METHODS: A prospective, observational cohort study in 305 patients 60 years or older undergoing a total hip or knee arthroplasty was conducted. Major outcome variables were distance walked in 6 minutes (6MWT), score on the Borg Scale for perception of effort, maximal dominant hand strength, and Short Form 36 (SF-36) QoL assessment in the preoperative and early postoperative periods. Patients were categorized according to their Hb level the day of the postoperative 6MWT (≤ 80, 81-90, 91-100, and >100 g/L). RESULTS: There was no difference between Hb groups in the decrease of the distance walked preoperatively versus postoperatively. For both moments of observation, the 6MWT was not significantly different between Hb groups (p = 0.190). Similar results were found with perception of effort, maximal dominant hand strength, and SF-36 QoL assessment scores. In a regression model, the decrease in Hb concentration could explain only 1.9% of the total variation observed in the 6MWT (p = 0.008). CONCLUSION: Moderate anemia is not associated with an impaired functional recovery or QoL in the immediate postoperative period after major arthroplasties. Further studies will be required to determine the long-term consequences of a restrictive transfusion strategy in these patients.

Tracheal intubation through the I-gel™ supraglottic airway versus the LMA Fastrach™: a randomized controlled trial.

BACKGROUND: The i-gel™ is a supraglottic airway device not requiring inflation of a cuff for lung ventilation. Its design allows for unobstructed passage of a tracheal tube and previous studies have demonstrated a favorable alignment with the glottic inlet. In this prospective randomized study, we compared the success rate of blind tracheal intubation using the i-gel and the laryngeal mask airway (LMA) Fastrach™. METHODS: One hundred sixty patients requiring general anesthesia and airway management were randomized to tracheal intubation using the i-gel or the LMA Fastrach. After induction of general anesthesia, the allocated device was inserted and adequate lung ventilation was confirmed. Blind tracheal intubation was then attempted. First attempt and overall tracheal intubation success rates were evaluated and tracheal intubation times were measured. RESULTS: Eighty patients were recruited in each study group. Successful tracheal intubation was obtained on the first attempt in 69% of patients with the i-gel and 74% of patients with the LMA Fastrach (95% confidence interval [CI] of difference, -9% to 19%, P = 0.60). The overall intubation success rate was lower using the i-gel than it was using the LMA Fastrach (73% vs 91%, 95% CI of difference, 7% to 31%, P < 0.0001). CONCLUSIONS: On first attempts, successful blind tracheal intubation was obtained at comparable rates using the i-gel and the LMA Fastrach. However, when the first attempt was unsuccessful, subsequent attempts through the i-gel did not significantly increase tracheal intubation success rate. The LMA Fastrach yielded a higher overall intubation success rate.

Atrial fibrillation after pulmonary transplantation: incidence, impact on mortality, treatment effectiveness, and risk factors.

BACKGROUND: Atrial fibrillation (AF) is common after thoracic surgery. Limited data exist concerning the incidence of AF, its impact on mortality, the effectiveness of therapy, and the risk factors of AF after pulmonary transplantation. METHODS AND RESULTS: We reviewed the medical files of 224 consecutive lung transplant recipients who underwent surgery over a 10-year period at a large Canadian center. We collected patient characteristics, in-hospital treatments, and outcomes. Time-to-event analysis was used to account for in-hospital follow-up and models generated to assess the impact of AF on mortality and independent risk factors of AF after transplantation. Postoperative AF occurred in 65 patients (29%). AF was more likely to occur with complications such as pneumonia, mediastinitis, and bronchial dehiscence and was not an independent risk factor of mortality (hazard ratio=1.56; 95% confidence interval, 0.52-4.63). Pharmacological or electric therapy for rhythm or rate control of AF was administered to 97% of patients. Intravenous amiodarone was used in 46%, electric cardioversion in 28%, and heparin in 26%. Only 1 patient remained in AF at discharge. Age (hazard ratio=1.08 by year; 95% confidence interval, 1.05-1.12), bilateral transplantation (hazard ratio=1.87; 95% confidence interval, 1.03-3.42), and a history of AF before the transplantation (hazard ratio=4.48; 95% confidence interval, 1.05-19.11) were found to be independently associated with an increased incidence of postoperative AF. CONCLUSIONS: AF is fairly common after pulmonary transplantation, transient, and relatively benign. It is not independently associated with increased in-hospital mortality. Most patients return to sinus rhythm before discharge. Age, prior AF, and bilateral transplantation increase the risk of postoperative AF.

O Kamasutra de Bush: muitas posições sobre o sexo

A publicação número 3 da Série "Políticas Públicas" da Coleção ABIA (Associação Brasileira Interdisciplinar de AIDS)aponta as implicações globais das políticas conservadoras sobre sexualidade do Governo dos Estados Unidos.

Superficial cervical plexus block for transitional analgesia in infratentorial and occipital craniotomy: a randomized trial.

BACKGROUND: In this study, we compared the quality of transitional analgesia provided by bilateral superficial cervical plexus block (SCPB) or morphine following a remifentanil-based anesthesia for infratentorial or occipital craniotomy. METHODS: In this randomized controlled and double-blind study, 30 patients scheduled for infratentorial or occipital craniotomy were divided randomly into two groups: group morphine (morphine 0.1 mg·kg⁻¹ iv after dural closure and a SCPB performed with 20 mL of 0.9% saline at the end of the surgery) or group block (10 mL of 0.9% saline iv instead of morphine after dural closure and a SCPB performed with 20 mL of a 1:1 mixture of 0.5% bupivacaine and 2% lidocaine at the end of the surgery). Postoperative pain was assessed at one, two, four, eight, 12, 16, and 24 hr using an 11-point (0-10) numerical rating scale (NRS). Analgesia was provided with subcutaneous codeine. RESULTS: Average NRS scores were similar between the two groups at each time interval over the study period. The average scores (with 95% confidence interval) were 3.9 (3.4-4.4) and 4.3 (3.8-4.9) for the block and morphine groups, respectively (P = 0.25). The delay before administration of the first dose of codeine was not statistically different between the two groups: 25 min (5-2,880) vs 21.5 min (5-90), median and range for the block and morphine groups, respectively. The incidence of nausea and vomiting was similar between the two groups. CONCLUSION: Bilateral superficial cervical plexus block provides transitional analgesia that is clinically equivalent to morphine following remifentanil-based anesthesia in patients undergoing occipital or infratentorial craniotomies.

Red blood cell transfusion practice in elective orthopedic surgery: a multicenter cohort study.

BACKGROUND: The indications for red blood cell (RBC) transfusions remain unclear despite published guidelines. Our hypothesis was that the transfusion practice varies inside the Centre hospitalier de l'Université de Montréal (CHUM). STUDY DESIGN AND METHODS: A total of 701 charts of patients who underwent a knee or hip arthroplasty or prosthesis revision in three hospitals of the CHUM were reviewed. Demography, hemoglobin (Hb) concentrations, details on transfusions, and postoperative adverse events (AEs) were collected up until discharge. The primary outcome was the presence or absence of RBC transfusion. Secondary outcomes were the nadir Hb, number of units transfused, discharge Hb, blood losses, and postoperative AEs. RESULTS: The rate of postoperative transfusion was 29%. We found no significant difference between odds ratios of each site for sex, coronary artery disease, chronic heart failure, type of procedure, American Society of Anesthesiologists physical status, weight, height, body mass index, body surface area, and estimated blood volume. Overall, patients were transfused at a Hb between 75 and 80g/L. Eighty-five percent of postoperative transfusions could be predicted using only nadir Hb and adding patient characteristics did not substantially improve the model (86.1%). Discharge Hb was below 100g/L in 66% of patients. CONCLUSIONS: There was no difference among hospitals regarding the way RBC transfusions are used. Our data suggest that physicians mainly based their decision to transfuse on a single variable, the Hb concentration, with the use of a restrictive strategy. Future trials should focus on the optimal transfusion trigger to adopt in major orthopedic surgery.