Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 2017
Prediction of difficult laryngoscopy using spirometry: a pilot study.
Prediction of difficult laryngoscopy is still the uncovered secret of anesthetic practice. This pilot study is aimed to assess the efficacy of spirometry measurements in predicting difficult laryngoscopy compared with conventional airway assessment techniques. We enrolled 202 adults, ages 18-40 years, with an American Society of Anaesthesiologists score of I or II, scheduled for elective surgery and undergoing general anesthesia. ⋯ In a multivariate linear regression model, all spirometry measurements revealed that forced inspiratory vital capacity (β = -2.050, P = 0.022) was the significant predictor for difficult laryngoscopy. The area under the curve for forced inspiratory vital capacity with a cut-off value of 3.1950 L while using thyromental distance as difficult laryngoscopy indicator is 0.754 and forced inspiratory vital capacity showed a sensitivity of 0.718 and specificity of 0.714 with a positive likelihood ratio of 2.5104 and negative likelihood ratio of 0.3949. Forced inspiratory vital capacity showed a close association with the prediction of difficult laryngoscopy.
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J Clin Monit Comput · Dec 2017
Observational StudyCentral venous-to-arterial carbon dioxide difference and the effect of venous hyperoxia: A limiting factor, or an additional marker of severity in shock?
Central venous-to-arterial carbon dioxide difference (PcvaCO2) has demonstrated its prognostic value in critically ill patients suffering from shock, and current expert recommendations advocate for further resuscitation interventions when PcvaCO2 is elevated. PcvaCO2 combination with arterial-venous oxygen content difference (PcvaCO2/CavO2) seems to enhance its performance when assessing anaerobic metabolism. However, the fact that PCO2 values might be altered by changes in blood O2 content (the Haldane effect), has been presented as a limitation of PCO2-derived variables. ⋯ PcvaCO2 and PcvaCO2/CavO2 are influenced by oxygenation changes not related to flow. Elevated PcvaCO2 and PcvaCO2/CavO2 values might not only derive from cardiac output inadequacy, but also from venous hyperoxia. Elevated PcvaCO2/CavO2 values were associated with higher PO2 transmission to the venous compartment, suggesting higher shunting phenomena.
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J Clin Monit Comput · Dec 2017
Comparative StudyComparison of non-invasive peripheral venous saturations with venous blood co-oximetry.
The estimation of venous oxygen saturations using photoplethysmography (PPG) may be useful as a noninvasive continuous method of detecting changes in regional oxygen supply and demand (e.g. in the splanchnic circulation). The aim of this research was to compare PPG-derived peripheral venous oxygen saturations directly with venous saturation measured from co-oximetry blood samples, to assess the feasibility of non-invasive local venous oxygen saturation. This paper comprises two similar studies: one in healthy spontaneously-breathing volunteers and one in mechanically ventilated anaesthetised patients. ⋯ In the anaesthetised patients SxvO2 values were only 3.81% lower than SpO2 and tended to underestimate venous saturation (mean difference = -2.67 ± 5.89%) while correlating weakly with ScovO2 (r = 0.10). The results suggest that significant refinement of the technique is needed to sufficiently improve accuracy to produce clinically meaningful measurement of peripheral venous oxygen saturation. In anaesthetised patients the use of the technique may be severely limited by cutaneous arteriovenous shunting.
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J Clin Monit Comput · Dec 2017
The influence of PEEP and positioning on central venous pressure and venous hepatic hemodynamics in patients undergoing liver resection.
In order to assess the occurrence of blood congestion in the liver during liver resection, we aimed to evaluate the influence of a positive-end-expiratory-pressure (PEEP) and positioning of patients on central venous pressure (CVP) and venous hepatic blood flow parameters. We further analyzed correlations between CVP and venous hepatic blood flow parameters. ⋯ Changes of central venous pressure due to changes of PEEP and positioning were not correlated with changes of venous hepatic blood flow parameters as measured after equilibration. Strategies aiming for low central venous pressure cannot be supported by these results. However, before ruling out low-CVP-strategies during liver resections these results should be confirmed by further studies.
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J Clin Monit Comput · Dec 2017
Observational StudyApplicability of stroke volume variation in patients of a general intensive care unit: a longitudinal observational study.
Sinus rhythm (SR) and controlled mechanical ventilation (CV) are mandatory for the applicability of respiratory changes of the arterial curve such as stroke volume variation (SVV) to predict fluid-responsiveness. Furthermore, several secondary limitations including tidal volumes <8 mL/kg and SVV-values within the "gray zone" of 9-13% impair prediction of fluid-responsiveness by SVV. Therefore, we investigated the prevalence of these four conditions in general ICU-patients. ⋯ In 9.7% (27/278) of the first measurements and in 12.8% (615/4801) of all measurements the patients did neither have SR nor CV. Only 20 of 278 (7.2%) of the first measurements and 8.2% of all measurements fulfilled both major criteria (CV, SR) and both minor criteria for the applicability of SVV. The applicability of SVV in ICU-patients is limited due to the absence of mandatory criteria during the majority of measurements.