Journal of clinical monitoring and computing
-
J Clin Monit Comput · Dec 2020
A simplified 4-parameter model of volumetric capnograms improves calculations of airway dead space and slope of Phase III.
To evaluate a compact and easily interpretable 4-parameter model describing the shape of the volumetric capnogram, and the resulting estimates of anatomical dead space (VDAW) and Phase III (alveolar plateau) slope (SIII). Data from of 8 mildly-endotoxemic pre-acute respiratory distress syndrome sheep were fitted to the proposed 4-parameter model (4p) and a previously established 7-parameter model (7p). Root mean square error (RMSE) and Akaike information criterion (AIC), as well as VDAW and SIII derived from each model were compared. ⋯ Mean differences between VDAW (2.1 ± 0.04 ml) and SIII (0.047 ± 0.004 mmHg/ml) from 7 and 4p were significant (p < 0.001), but within the observed cycle-by-cycle variability. The proposed 4-parameter model of the volumetric capnogram improves data fitting and estimation of VDAW and SIII as compared to the 7-parameter model of reference. These advantages support the use of the 4-parameter model in future research and clinical applications.
-
J Clin Monit Comput · Dec 2020
Right ventricular transverse displacement increases following cardiac surgery: possibly compensating loss in tricuspid annular plane systolic excursion (TAPSE).
Right Ventricular (RV) output mostly derives from longitudinal shortening in normal hearts. However, following even uncomplicated cardiac surgery with preserved RV function a significant and sustained decrease in longitudinal contraction has been observed. How the RV compensates and sustains output in this setting remains unsettled. ⋯ RV speckle tracking strain did not change significantly. Increased transverse displacement likely compensates for reduction in RV longitudinal contraction following cardiac surgery and maintains cardiac output. The sustained output from the right ventricle was not related to an increased contractility.
-
J Clin Monit Comput · Dec 2020
Optimized electrical bioimpedance measurements of abdominal wall on a porcine model for the continuous non-invasive assessment of intra-abdominal pressure.
This work describes the optimization of electrical bioimpedance measurements for indirect intra-abdominal pressure (IAP) assessment. The experimental run was performed on a female Sus scrofa domesticus (domestic pig). Different values of IAP were induced by inflation of the abdominal cavity, using a trocar placed near the umbilicus over the linea alba. ⋯ An exponential trend linking between the bioimpedance values at 99.8 kHz and the IAP was found. Non-optimized electrode placement presented a strongly reduced sensitivity to IAP changes above 7 mmHg. Upon optimization and placing the electrodes with a separation of about 3.6 times the measured abdominal wall thickness, the sensitivity for high IAP drastically increased, allowing continuous non-invasive monitoring of IAP, confirming the optimization method proposed in this work.
-
J Clin Monit Comput · Dec 2020
Observational StudyAccuracy of the non-invasive Tcore™ temperature monitoring system to measure body core temperature in abdominal surgery.
An accurate determination of body core temperature is crucial during surgery in order to avoid and treat hypothermia, which is associated with poor outcome. In a prospective observational study, we evaluated the suitability of the Tcore™ device (Drägerwerk AG & Co. KGaA, Lübeck, Germany)-a non-invasive thermometer-to accurately determine core body temperature. ⋯ In a repeated-measurements version of the Bland and Altman test, a bias of - 0.02 °C and 95% limits of agreement of - 0.48 to 0.44 °C were calculated. In a population analysis, a median absolute error of 0 [- 0.1; + 0.1] °C, a bias of 0 [- 0.276; 0.271] % and an inaccuracy of 0.276 [0.274; 0.354] % was determined. Although the Tcore™ sensor was attached to the frontal skin, it provided an accurate measurement of core body temperature in the investigated intraoperative setting.