Quantitative assessment of cardiac load-responsiveness during extracorporeal life support: case and rationale

We describe a case of a patient assisted by extracorporeal life support, in which we obtained the dynamic filling index, a measure for venous volume during extracorporeal life support, and used this index to assess cardiac load-responsiveness during acute reloading. While reloading, the obtained findings on cardiac pump function by the dynamic filling index were supported by trans-esophageal echocardiography and standard pressure measurement. This suggests that the dynamic filling index can be used to assess cardiac load-responsiveness during extracorporeal life support

Accuracy, Precision, and Trending Ability of Electrical Cardiometry Cardiac Index versus Continuous Pulmonary Artery Thermodilution Method : A Prospective, Observational Study

Introduction: Evaluation of accuracy, precision, and trending ability of cardiac index (CI) measurements using the Aesculon™ bioimpedance electrical cardiometry (Aesc) compared to the continuous pulmonary artery thermodilution catheter (PAC) technique before, during, and after cardiac surgery. Methods: A prospective observational study with fifty patients with ASA 3-4. At six time points (T), measurements of CI simultaneously by continuous cardiac output pulmonary thermodilution and thoracic bioimpedance and standard hemodynamics were performed. Analysis was performed using Bland-Altman, four-quadrant plot, and polar plot methodology. Results: CI obtained with pulmonary artery thermodilution and thoracic bioimpedance ranged from 1.00 to 6.75 L min-1 and 0.93 to 7.25 L min-1, respectively. Bland-Altman analysis showed a bias between CIBIO and CIPAC of 0.52 liters min-1 m-2, with LOA of [-2.2; 1.1] liters min-1 m-2. Percentage error between the two techniques was above 30% at every time point. Polar plot methodology and 4-quadrant analysis showed poor trending ability. Skin incision had no effect on the results. Conclusion: CI obtained by continuous PAC and CI obtained by Aesculon bioimpedance are not interchangeable in cardiac surgical patients. No effects of skin incision were found. International clinical trial registration number is ISRCTN26732484

The use of regression analysis in determining reference intervals for low hematocrit and thrombocyte count in multiple electrode aggregometry and platelet function analyzer 100 testing of platelet function

Low platelet counts and hematocrit levels hinder whole blood point-of-care testing of platelet function. Thus far, no reference ranges for MEA (multiple electrode aggregometry) and PFA-100 (platelet function analyzer 100) devices exist for low ranges. Through dilution methods of volunteer whole blood, platelet function at low ranges of platelet count and hematocrit levels was assessed on MEA for four agonists and for PFA-100 in two cartridges. Using (multiple) regression analysis, 95% reference intervals were computed for these low ranges. Low platelet counts affected MEA in a positive correlation (all agonists showed r2 ≥ 0.75) and PFA-100 in an inverse correlation (closure times were prolonged with lower platelet counts). Lowered hematocrit did not affect MEA testing, except for arachidonic acid activation (ASPI), which showed a weak positive correlation (r2 = 0.14). Closure time on PFA-100 testing was inversely correlated with hematocrit for both cartridges. Regression analysis revealed different 95% reference intervals in comparison with originally established intervals for both MEA and PFA-100 in low platelet or hematocrit conditions. Multiple regression analysis of ASPI and both tests on the PFA-100 for combined low platelet and hematocrit conditions revealed that only PFA-100 testing should be adjusted for both thrombocytopenia and anemia. 95% reference intervals were calculated using multiple regression analysis. However, coefficients of determination of PFA-100 were poor, and some variance remained unexplained. Thus, in this pilot study using (multiple) regression analysis, we could establish reference intervals of platelet function in anemia and thrombocytopenia conditions on PFA-100 and in thrombocytopenia conditions on MEA

Whole blood thrombin generation parameters of the resting control group.

<p>Thrombin generation was started with 0.5 pM TF and 16.7 mM CaCl₂. The parameters depicted are the Peak height (A), ETP (B), Lagtime (C) and Time-to-peak (D). Data are median percentages normalized to day 1 with interquartile ranges (N = 7).</p

Thrombin generation in plasma.

<p>Thrombin generation was started with 1 pM TF, 4 μM phospholipid vesicles and 16.7 mM CaCl₂. The parameters depicted are the Peak height (A), ETP (B), Lagtime (C) and Time-to-peak (D). Data are medians with interquartile ranges.</p

Fibrinogen (A), von Willebrand factor (B) and FVIII (C) levels in plasma.

<p>Data are medians with interquartile ranges. *p<0.05.</p

Effect of hypoxia on oxygen saturation, heart rate, blood pressure, altitude symptom score and paracetamol intake.

<p>Data are medians with interquartile ranges (A-D) or mean with SEM (E-F). *p<0.05.</p

Basic characteristics of both groups at 50 m (day 1).

<p>Data are mean values ± SD.</p