Transpulmonary thermodilution: A revised correction formula for global end-diastolic volume index derived after femoral indicator injection.

PURPOSE: Transpulmonary thermodilution (TPTD) is usually performed by jugular indicator injection. In clinical practice, femoral venous access is often used instead, resulting in substantial overestimation of global end-diastolic volume index (GEDVI). A correction formula compensates for that. The objective of this study is to first evaluate the efficacy of the currently implemented correction function and then further improve this formula. METHODS: The performance of the established correction formula was investigated in our prospectively collected dataset of 98 TPTD measurements from 38 patients with both, jugular and femoral venous access. Subsequently, a new correction formula was developed: cross validation revealed the favourite covariate combination and a general estimating equation provided the final version, which was tested in a retrospective validation on an external dataset. RESULTS: Investigating the current correction function revealed a considerable reduction of bias compared to no correction. Concerning the objective of formula development, the covariate combination of GEDVI obtained after femoral indicator injection, age and body surface area is even favoured, when compared to the parameters of the previously published correction formula, as a further reduction of mean absolute error (68 vs. 61 ml/m2), a better correlation (0.90 vs. 0.91) and an increased adjusted R2 (0.72 vs 0.78) is noticed in the cross validation results. Of particular clinical importance is, that more measurements were correctly assigned to the same GEDVI category (decreased / normal / increased) using the revised formula, compared with the gold standard of jugular indicator injection (72.4 vs. 74.5%). In a retrospective validation, the newly developed formula showed a greater reduction of bias (to 2 vs. 6 %) than the currently implemented formula. CONCLUSIONS: The currently implemented correction function partly compensates for GEDVI overestimation. Applying the new correction formula on GEDVI measured after femoral indicator administration enhances the informative value and reliability of this preload parameter.

Accuracy of hemodynamic parameters derived by GE E-PiCCO in comparison with PiCCO® in patients admitted to the intensive care unit.

To evaluate the agreement and accuracy of a novel advanced hemodynamic monitoring (AHM) device, the GE E-PiCCO module, with the well-established PiCCO® device in intensive care patients using pulse contour analysis (PCA) and transpulmonary thermodilution (TPTD). A total of 108 measurements were performed in 15 patients with AHM. Each of the 27 measurement sequences (one to four per patient) consisted of a femoral and a jugular indicator injection via central venous catheters (CVC) and measurement using both PiCCO (PiCCO® Jug and Fem) and GE E-PiCCO (GE E-PiCCO Jug and Fem) devices. For statistical analysis, Bland-Altman plots were used to compare the estimated values derived from both devices. The cardiac index measured via PCA (CIpc) and TPTD (CItd) was the only parameter that fulfilled all a priori-defined criteria based on bias and the limits of agreement (LoA) by the Bland-Altman method as well as the percentage error by Critchley and Critchley for all three comparison pairs (GE E-PiCCO Jug vs. PiCCO® Jug, GE E-PiCCO Fem vs. PiCCO® Fem, and GE E-PiCCO Fem vs. GE E-PiCCO Jug), while the GE E-PiCCO did not accurately estimate EVLWI, SVRI, SVV, and PPV values measured via the jugular and femoral CVC compared with values assessed by PiCCO®. Consequently, measurement discrepancy should be considered on evaluation and interpretation of the hemodynamic status of patients admitted to the ICU when using the GE E-PiCCO module instead of the PiCCO® device.

Synthesis of the B-seco limonoid core scaffold.

Synthetic investigations towards the structurally complex and highly decorated framework of B-seco limonoid natural products by means of a [3,3]-sigmatropic rearrangement are described. Detailed model studies reveal, that an Ireland-Claisen rearrangement can be employed to construct the central C9-C10 bond thereby giving access to the B-seco limonoid scaffold. However, application of the developed strategy ended up failing in more complex and sterically demanding systems.

Synthesis of the B-seco limonoid scaffold.

The underlying stereochemically complex and densely functionalized scaffold of the B-seco limonoids was synthesized employing an Ireland-Claisen rearrangement as key transformation.