Journal of clinical monitoring and computing
-
Any measurement is always afflicted with some degree of uncertainty. A correct understanding of the different types of uncertainty, their naming, and their definition is of crucial importance for an appropriate use of measuring instruments. However, in perioperative and intensive care medicine, the metrological requirements for measuring instruments are poorly defined and often used spuriously. ⋯ It is therefore the task of the scientific societies to establish the standards in their area of expertise. Adopting the same understandings and definitions among clinicians and scientists is obviously the first step. In this metrologic review (part 1), we list and explain the most important terms defined by the International Bureau of Weights and Measures regarding quantities and units, properties of measurements, devices for measurement, properties of measuring devices, and measurement standards, with specific examples from perioperative and intensive care medicine.
-
J Clin Monit Comput · Feb 2021
ReviewMetrology part 2: Procedures for the validation of major measurement quality criteria and measuring instrument properties.
A measurement is always afflicted with some degree of uncertainty. A correct understanding of the different types of uncertainty, their naming, and their definition is of crucial importance for an appropriate use of the measuring instruments. However, in perioperative and intensive care medicine, the metrological requirements for measuring instruments are poorly defined and often used spuriously. ⋯ It is therefore the task of scientific societies to establish the standards in their area of expertise. After adopting the same understandings and definitions (part 1), the different procedures for the validation of major quality criteria of measuring devices must be consensually established. In this metrologic review (part 2), we review the terms and definitions of validation, some basic processes leading to the display of an indication from a physiologic signal, and procedures for the validation of measuring instrument properties, with specific focus on perioperative and intensive care medicine including appropriate examples.
-
J Clin Monit Comput · Feb 2021
Pulse oximetry based on photoplethysmography imaging with red and green light : Calibratability and challenges.
Remotely measuring the arterial blood oxygen saturation (SpO2) in visible light (Vis) involves different probing depths, which may compromise calibratibility. This paper assesses the feasibility of calibrating camera-based SpO2 (SpO2,cam) using red and green light. Camera-based photoplethysmographic (PPG) signals were measured at 46 healthy adults at center wavelengths of 580 nm (green), 675 nm (red), and 840 nm (near-infrared; NIR). ⋯ Additional measurements on normoxic subjects under temperature cooling (from [Formula: see text] to [Formula: see text]) evidenced a significant bias of - 1.7, CI [- 2.7, - 0.7]%. It was also noted that SpO[Formula: see text] estimated at the cheeks was significantly biased (- 3.6, CI [- 5.7, - 1.5]%) with respect to forehead estimations. Under controlled conditions, SpO[Formula: see text] can be calibrated with red and green light but the accuracy is less than that of SpO[Formula: see text] estimated in the usual red-NIR window.
-
From home to intensive care units, innovations in pulse oximetry are susceptible to improve the monitoring and management of patients developing acute respiratory failure, and particularly those with the coronavirus disease 2019 (COVID-19). They include self-monitoring of oxygen saturation (SpO2) from home, continuous wireless SpO2 monitoring on hospital wards, and the integration of SpO2 as the input variable for closed-loop oxygen administration systems. The analysis of the pulse oximetry waveform may help to quantify respiratory efforts and prevent intubation delays. Tracking changes in the peripheral perfusion index during a preload-modifying maneuver may be useful to predict preload responsiveness and rationalize fluid therapy.
-
J Clin Monit Comput · Feb 2021
ReviewA concise overview of non-invasive intra-abdominal pressure measurement techniques: from bench to bedside.
This review presents an overview of previously reported non-invasive intra-abdominal pressure (IAP) measurement techniques. Each section covers the basic physical principles and methodology of the various measurement techniques, the experimental results, and the advantages and disadvantages of each method. The most promising non-invasive methods for IAP measurement are microwave reflectometry and ultrasound assessment, in combination with an applied external force.