Goal-directed fluid management based on pulse pressure variation monitoring during high-risk surgery: a pilot randomized controlled trial

Abstract\ud \ud \ud \ud Introduction\ud \ud Several studies have shown that maximizing stroke volume (or increasing it until a plateau is reached) by volume loading during high-risk surgery may improve post-operative outcome. This goal could be achieved simply by minimizing the variation in arterial pulse pressure (ΔPP) induced by mechanical ventilation. We tested this hypothesis in a prospective, randomized, single-centre study. The primary endpoint was the length of postoperative stay in hospital.\ud \ud \ud \ud Methods\ud \ud Thirty-three patients undergoing high-risk surgery were randomized either to a control group (group C, n = 16) or to an intervention group (group I, n = 17). In group I, ΔPP was continuously monitored during surgery by a multiparameter bedside monitor and minimized to 10% or less by volume loading.\ud \ud \ud \ud Results\ud \ud Both groups were comparable in terms of demographic data, American Society of Anesthesiology score, type, and duration of surgery. During surgery, group I received more fluid than group C (4,618 ± 1,557 versus 1,694 ± 705 ml (mean ± SD), P < 0.0001), and ΔPP decreased from 22 ± 75 to 9 ± 1% (P < 0.05) in group I. The median duration of postoperative stay in hospital (7 versus 17 days, P < 0.01) was lower in group I than in group C. The number of postoperative complications per patient (1.4 ± 2.1 versus 3.9 ± 2.8, P < 0.05), as well as the median duration of mechanical ventilation (1 versus 5 days, P < 0.05) and stay in the intensive care unit (3 versus 9 days, P < 0.01) was also lower in group I.\ud \ud \ud \ud Conclusion\ud \ud Monitoring and minimizing ΔPP by volume loading during high-risk surgery improves postoperative outcome and decreases the length of stay in hospital.\ud \ud \ud \ud Trial registration\ud \ud NCT00479011The authors thank Maria De Amorim (Paris, France) and Julia Fukushima (São Paulo, SP, Brazil) for help in data analysis, Dr Julia Wendon (London, UK) for reviewing the manuscript, and Dixtal (Sao Paulo, SP, Brazil) for providing the software for the automatic calculation of ?PP.The authors thank Maria De Amorim (Paris, France) and Julia Fukushima (São Paulo, SP, Brazil) for help in data analysis, Dr Julia Wendon (London, UK) for reviewing the manuscript, and Dixtal (Sao Paulo, SP, Brazil) for providing the software for the automatic calculation of ?PP

Détermination des caractéristiques mécaniques au cisaillement des argiles litées cas du glissement de la combe d’Harmalière

L'étude concerne un vaste glissement de terrain (45 hectares), situé à 35 km au sud de Grenoble, dont la rupture s'est produite le 7 mars 1981 au sein d'une formation d'argiles lacustres litées. D'une part, nous avons mis en œuvre une analyse a posteriori permettant d'évaluer les caractéristiques mécaniques globales à la rupture (cohésion et angle de frottement) que nous avons ensuite pu vérifier à l'aide de la méthode des éléments finis basée sur la théorie de l'élasto-plasticité. D'autre part, nous avons mis en œuvre une série d'essais in situ par pressiométrie ainsi qu'un programme d'essais de laboratoire (essai triaxial). De ces deux séries d'essais, nous tirons un ensemble de caractéristiques mécaniques que nous comparons aux caractéristiques déduites de l'analyse a posteriori

Non-invasive measurement of pulse pressure variation and systolic pressure variation using a finger cuff corresponds with intra-arterial measurement

Item does not contain fulltextBACKGROUND: Pulse pressure variation (PPV) and systolic pressure variation (SPV) are reliable predictors of fluid responsiveness in patients undergoing controlled mechanical ventilation. Currently, PPV and SPV are measured invasively and it is unknown if an arterial pressure (AP) signal obtained with a finger cuff can be used as an alternative. The aim of this study was to validate PPV and SPV measured using a finger cuff. METHODS: Patients receiving mechanical ventilation under sedation after cardiac artery bypass graft (CABG) surgery were included after arrival on the intensive care unit. AP was measured invasively in the radial artery and non-invasively using the finger cuff of the Nexfin monitor. I.V. fluid challenges were administered according to clinical need. The mean value of PPV and SVV was calculated before and after administration of a fluid challenge. Agreement of the calculated PPV and SPV from both methods was assessed using the Bland-Altman analysis. RESULTS: Nineteen patients were included and 28 volume challenges were analysed. Correlation between the two methods for PPV and SPV [mean (sd)=6.9 (4.3)% and 5.3 (2.6)%, respectively] was r=0.96 (P<0.0001) and r=0.95 (P<0.0001), respectively. The mean bias was -0.95% for PPV and -0.22% for SPV. Limits of agreement were -4.3% and 2.4% for PPV and -2.2% and 1.7% for SPV. The correlation between changes in PPV and SPV as a result of volume expansion measured by the two different methods was r=0.88 (P<0.0001) and r=0.87 (P<0.0001), respectively. CONCLUSIONS: In patients receiving controlled mechanical ventilation after CABG, PPV and SPV can be measured reliably non-invasively using the inflatable finger cuff of the Nexfin monitor

Determinants of arterial and central venous blood pressure variation in ventilated critically ill children

PURPOSE: Ventilation-induced arterial pressure variation predicts volume responsiveness in adults. Several factors are known to influence the interpretability of these variations. We analysed ventilation-induced variations in critically ill children with reference to ventilatory and circulatory parameters. METHODS: We prospectively included 20 paediatric patients. Variation of systolic pressure (SPV), pulse pressure (PPV) and central venous pressure (CVP) were assessed during pressure-controlled ventilation with inspiratory pressures (P(insp)) of 20 and 28 cmH(2)O. Blood gases were analysed and echocardiography was performed. RESULTS: SPV, PPV and CVP variation significantly increased with elevated P(insp) (p < 0.001, p = 0.008 and p = 0.003). Baseline CVP and shortening fraction were significant negative predictors of PPV and SPV. CONCLUSION: This preliminary study identified P(insp) as a determinant of SPV, PPV and CVP variation in children. Further independent determinants of SPV and PPV were baseline CVP and ventricular performance, both of which must be considered when interpreting pressure variations

Continuous non-invasive finger arterial pressure monitoring reflects intra-arterial pressure changes in children undergoing cardiac surgery.

Contains fulltext : 88974.pdf (publisher's version ) (Closed access)BACKGROUND: Continuous non-invasive measurement of finger arterial pressure (FAP) is a reliable technology in adults. FAP is measured with an inflatable cuff around the finger and simultaneously converted to a reconstructed brachial artery pressure waveform (reBAP) by the Nexfin device. We assessed the adequacy of a prototype device (Nexfin-paediatric), designed for a paediatric population, for detecting rapid arterial pressure changes in children during cardiac surgery. METHODS: Thirteen anaesthetized children with a median age of 11 months (2 months-7 yr) undergoing congenital cardiac surgery were included in the study. reBAP and intra-arterial pressure (IAP) were recorded simultaneously during the surgical procedure. To assess the accuracy of reBAP in tracking arterial pressure changes, the four largest IAP variations within a 5 min time interval were identified from each procedure. These variations were compared offline with reBAP during a 10 s control period before and a 10 s period after an arterial pressure change had occurred. RESULTS: In 10 out of 13 children, a non-invasive arterial pressure recording could be obtained. Therefore, recordings from these 10 children were eligible for further analysis, resulting in 40 data points. The correlation coefficient between reBAP and IAP in tracking mean arterial pressure (MAP) changes was 0.98. reBAP followed changes in IAP with a mean bias for systolic, diastolic arterial pressure, and MAP of 0.0 mm Hg (sd 5.8), 0.1 (sd 2.8), and 0.19 (sd 2.7), respectively. CONCLUSIONS: The prototype device closely follows arterial pressure changes in children. However, in a considerable number of attempts, obtaining a signal was time-consuming or unsuccessful. This technique seems promising but requires further technical development.1 oktober 201

Roles of mental translation in first and foreign language reading

[[abstract]]This study integrates both quantitative and qualitative approaches to examine the roles that mental translation plays in reading classical Chinese and English as a foreign language among Taiwanese high school students. Gadamer’s theory of hermeneutic experience and the Vygotskian social-cultural theory provide the theoretical frameworks for this study. The quantitative data consist of reading comprehension tests and translation surveys, while the qualitative data are composed of think-aloud protocols and interviews with the participating students and their teachers. At least two prominent findings emerge from the data analyses: (1) mental translation appears to have positive and significant associations with reading comprehension across two languages; (2) ambivalent perceptions of and attitudes toward the employment of mental translation for reading classical literary Chinese and English are discerned. The findings support Gadamer’s contention that humans learn to translate as they are learning a language. The views and ideas expressed by the participating teachers and students uncover a sociocultural dimension of reading, as proposed by Vygotsky.[[incitationindex]]SSCI[[booktype]]紙