Journal of clinical monitoring and computing
-
J Clin Monit Comput · Oct 2023
Observational StudyEvaluation of the accuracy of oscillometric non-invasive blood pressure measurement at the ankle in children during general anesthesia.
This study aimed to evaluate the accuracy of oscillometric blood pressure measurement at the ankle in children using invasive blood pressure as reference standard. This prospective observational study included children undergoing noncardiac surgery. Paired radial invasive and ankle non-invasive blood pressure measurements were obtained. ⋯ The concordance rate of ankle blood pressure was 72%, 71%, and 77% for delta SBP, DBP and MAP, respectively. The AUC (95% confidence interval) for ankle MAP ability to detect hypotension was 0.91 (0.89-0.93) with negative predictive value of 100% at cut-off value ≤ 70 mmHg, We concluded that in pediatric population undergoing noncardiac surgery, ankle blood pressure was not interchangeable with the corresponding invasive readings with the ankle MAP having the least bias compared to SBP and DBP. An ankle MAP > 70 mmHg can exclude hypotension with negative predictive value of 100%.
-
J Clin Monit Comput · Oct 2023
Single-FiO2 lung modelling with machine learning: a computer simulation incorporating volumetric capnography.
We investigated whether machine learning (ML) analysis of ICU monitoring data incorporating volumetric capnography measurements of mean alveolar PCO2 can partition venous admixture (VenAd) into its shunt and low V/Q components without manipulating the inspired oxygen fraction (FiO2). From a 21-compartment ventilation / perfusion (V/Q) model of pulmonary blood flow we generated blood gas and mean alveolar PCO2 data in simulated scenarios with shunt values from 7.3% to 36.5% and a range of FiO2 settings, indirect calorimetry and cardiac output measurements and acid- base and hemoglobin oxygen affinity conditions. A 'deep learning' ML application, trained and validated solely on single FiO2 bedside monitoring data from 14,736 scenarios, then recovered shunt values in 500 test scenarios with true shunt values 'held back'. ⋯ With corresponding VenAd values calculated from the same bedside data, low V/Q flow can be reported as VenAd-shunt. ML analysis of blood gas, indirect calorimetry, volumetric capnography and cardiac output measurements can quantify pulmonary oxygenation deficits as percentage shunt flow (V/Q = 0) versus percentage low V/Q flow (V/Q > 0). High fidelity reports are possible from analysis of data collected solely at the operating FiO2.
-
J Clin Monit Comput · Oct 2023
Changes in EEG frequency characteristics during sevoflurane general anesthesia: feature extraction by variational mode decomposition.
Mode decomposition is a method for extracting the characteristic intrinsic mode function (IMF) from various multidimensional time-series signals. Variational mode decomposition (VMD) searches for IMFs by optimizing the bandwidth to a narrow band with the [Formula: see text] norm while preserving the online estimated central frequency. In this study, we applied VMD to the analysis of electroencephalogram (EEG) recorded during general anesthesia. ⋯ IMF-2, IMF-3, IMF-4, IMF-5, and IMF-6 increased significantly from 1.4 (1.2-1.6) Hz to 7.5 (1.5-9.3) Hz, 6.7 (4.1-7.6) Hz to 19.4 (6.9-20.0) Hz, 10.9 (8.8-11.4) Hz to 26.4 (24.2-27.2) Hz, 13.4 (11.3-16.6) Hz to 35.6 (34.9-36.1) Hz, and 12.4 (9.7-18.1) Hz to 43.2 (42.9-43.4) Hz, respectively. The characteristic frequency component changes in specific IMFs during emergence from general anesthesia were visually captured by IMFs derived using VMD. EEG analysis by VMD is useful for extracting distinct changes during general anesthesia.
-
J Clin Monit Comput · Oct 2023
Evaluation of temperature-dependent fluctuations in skin microcirculation flow using a light-emitting diode based photoacoustic imaging device.
Skin microvessels maintain temperature homeostasis by contracting and dilating upon exposure to changes in temperature. Under general anesthesia, surgical invasiveness, including incisions and coagulation, and the effects of anesthetics may cause variations in the threshold temperature, leading to the constriction and dilation of cutaneous blood vessels. Therefore, studies on skin microvascular circulation are necessary to develop appropriate interventions for complications during surgery. ⋯ These findings suggest that the LED-PAI device could be an option for evaluating microcirculation in association with changes in temperature.
-
J Clin Monit Comput · Aug 2023
Multicenter StudyAgreement between pulse oximetry and arterial oxygen saturation measurement in critical care patients during COVID-19: a cross-sectional study.
Some publications suggest that pulse oximetry measurement (SpO2) might overestimate arterial oxygen saturation (SaO2) measurement in COVID-19 patients. This study aims to evaluate the agreement between SpO2 and SaO2 among COVID-19 and non-COVID-19 patients. We conducted a multicenter, prospective study including consecutive intensive care patients from October 15, 2020, to March 4, 2021, and compared for each measurement the difference between SpO2 and SaO2, also called the systematic bias. ⋯ In our population, agreement between SpO2 and SaO2 is acceptable. During the COVID-19 pandemic, SaO2 remains an efficient monitoring tool to characterise the level of hypoxemia and follow therapeutic interventions. As is already known about general intensive care unit patients, the greater hypoxemia, the weaker the correlation between SpO2 and SaO2.