Comparison of Pocket Pulse Oximeter and Standard Pulse Oximeter With ABG Analysis in Critically Ill Patients

Background: Pulse oximetry (SpO2) is a standard monitoring device in patients presenting to EMDs and intensive care units (ICUs). Pocket pulse oximeters (PPOs) are used widely in wards, EMDs, and small hospitals/clinics. These inexpensive PPOs also guide therapeutic interventions. Few studies have evaluated the accuracy of SpO2 in patients presenting to critical care areas vis-à-vis devices like PPO and standard pulse oximeter (SPO). This study becomes extremely relevant in view of the ongoing crisis of the COVID-19 pandemic wherein SpO2 monitoring is very important in hospitals, quarantine centers, small clinics, or even at home. Methods: Patients presenting to critical areas who underwent arterial blood gases (ABG) analysis on the recommendation of the treating physician between November 2016 and October 2018 were included in this study. Along with the ABG analysis, a simultaneous assessment of SpO2 was done with a single PPO and SPO and all values were noted. Statistical analysis was done using the SPSS v.21.0 for Windows. Results: The study included 300 patients. We compared the O2 saturations of ABG, SPO, and PPO with respect to sex, different age groups, and at different levels of ABG pCO2, HCO3, and pH in all patients. All parameters were compared using the Pearson’s correlation test; the results showed that ABG O2 saturations were closer to the SPO than the PPO but the differences were not statistically significant as the Pearson’s correlation values for all parameters were >0.8. We also compared the parameters by Bland Altman Plot and all observations were outside 95% CI (confidence interval), which means that there was a good agreement between O2 saturations by all three methods, that is, ABG, SPO, and PPO; however, ABG O2 saturations were closer to SPO than PPO but this difference was not statistically significant. Hence, we conclude that the PPO is a useful tool for reliable monitoring of O2 saturations. Conclusion: This study highlights that inexpensive and noninvasive PPO can be used as a standard monitoring device with reliability in critically ill patients presenting to EMDs, ICUs, and small hospitals/clinics, quarantine centers, and even at home.

X-ray image denoising based on wavelet transform and median filter

This paper mainly proposed and researched based on wavelet transform, and then used the X-map denoising technique of value filter. In other words, the value image was filtered in the spatial domain, and the value filtering was used as the standard pulse (salt) noise, also used as in the wavelet domain. After the filtered image was decomposed by biorthogonal double wavelet transform, a wavelet coefficient matrix was generated, and a soft threshold quantisation process was performed on the wavelet coefficients to produce a new wavelet coefficient matrix. In the end, they used a new wavelet coefficient matrix for image reconstruction. The processing resulted that the denoising method proposed in this paper showed that the X image can be denoised, which not only reduced the X-picture-like noise but also preserved the X-picture-like details as much as possible. It also helped to enhance diagnostic accuracy and reduced the difference in reading.

Thinking Out-of-the-Box: A Non-Standard Application of Standard Pulse-Oximetry and Standard Near-Infrared Spectroscopy in a COVID-19 Patient

Purpose: Purpose of this report is to describe the feasibility of lingual pulse oximetry and lingual near-infrared spectroscopy (NIRS) in a COVID-19 patient to assess lingual tissue viability after several days of mechanical ventilation in the prone position. Materials & Methods: In a COVID-19 ICU-patient, the tongue became grotesquely swollen, hardened and protruding from the oral cavity after 20 h of mechanical ventilation uninterrupted in the prone position. To assess the doubtful viability of the tongue, pulse-oximetric hemoglobin O2-saturation (SpO2; Nellcor, OxiMax MAX-NI, Covidien, MA, USA) and NIRS-based, regional tissue O2-saturation measurements (rSO2; SenSmart, Nonin, MN, USA) were performed at the tongue. Results: At the tongue, regular pulse-oximetric waveforms with a pulse-oximetric hemoglobin O2-saturation (SpO2) of 88% were recorded, i.e. only slightly lower than the SpO2 reading at the extremities at that time (90%). Lingual NIRS-based rSO2 measurements yielded stable tissue rSO2-values of 76-78%, i.e. values expected also in other adequately perfused and oxygenated (muscle-) tissues. Conclusion: Despite the alarming, clinical finding of a grotesquely swollen, rubber-hard tongue and clinical concerns on the adequacy of the tongue perfusion and oxygenation, our measurements of both arterial pulsatility (SpO2) and NIRS-based tissue oxygenation (rSO2) suggested adequate perfusion and oxygenation of the tongue, rendering non-vitality of the tongue, e.g. by lingual venous thrombosis, unlikely. To our knowledge, this is the first clinical report of lingual rSO2 measurement.

DETONABILITY OF FUEL-AIR MIXTURES IN TERMS OF DEFLAGRATION-TO-DETONATION TRANSITION

A new experimental method for evaluating the detonability of fuel-air mixtures (FAMs) based on measuring the deflagration-to-detonation (DDT) run-up distance and/or time in a standard pulse detonation tube is used to rank gaseous premixed and nonpremixed FAMs by their detonability under substantially identical thermodynamic and gasdynamic conditions. In the experiments, FAMs based on hydrogen, acetylene, ethylene, propylene, propane-butane, n-pentane, and natural gas of various compositions, as well as FAMs based on the gaseous pyrolysis products of polyethylene (PE) and polypropylene (PP) are used: from extremely fuel-lean to extremely fuel-rich at normal temperatures and pressures.

Pulse Rate Variability in Emergency Physicians During Shifts: Pilot Cross-Sectional Study

Background The high prevalence of physician burnout, particularly in emergency medicine, has garnered national attention in recent years. Objective means of measuring stress while at work can facilitate research into stress reduction interventions, and wearable photoplethysmography (PPG) technology has been proposed as a potential solution. However, the use of low-burden wearable biosensors to study training and clinical practice among emergency physicians (EP) remains untested. Objective This pilot study aimed to (1) determine the feasibility of recording on-shift photoplethysmographic data from EP, (2) assess the quality of these data, and (3) calculate standard pulse rate variability (PRV) metrics from the acquired dataset and examine patterns in these variables over the course of an academic year. Methods A total of 21 EP wore PPG biosensors on their wrists during clinical work in the emergency department during a 9-hour shift. Recordings were collected during the first quarter of the academic year, then again during the fourth quarter of the same year for comparison. The overall rate of usable data collection per time was computed. Standard pulse rate (PR) and PRV metrics from these two time points were calculated and entered into Student t tests. Results More than 400 hours of data were entered into these analyses. Interpretable data were captured during 8.54% of the total recording time overall. In the fourth quarter of the academic year compared with the first quarter, there was no significant difference in median PR (75.8 vs 76.8; P=.57), mean R-R interval (0.81 vs 0.80; P=.32), SD of R-R interval (0.11 vs 0.11; P=.93), root mean square of successive difference of R-R interval (0.81 vs 0.80; P=.96), low-frequency power (3.5×103 vs 3.4×103; P=.79), high-frequency power (8.5×103 vs 8.3×103; P=.91), or low-frequency to high-frequency ratio (0.42 vs 0.41; P=.43), respectively. Power estimates for each of these tests exceeded .90. A secondary analysis of the resident-only subgroup similarly showed no significant differences over time, despite power estimates greater than .80. Conclusions Although the use of PPG biosensors to record real-time physiological data from EP while providing clinical care seems operationally feasible, this study fails to support the notion that such an approach can efficiently provide reliable estimates of metrics of interest. No significant differences in PR or PRV metrics were found at the end of the year compared with the beginning. Although these methods may offer useful applications to other domains, it may currently have limited utility in the contexts of physician training and wellness.

BONE MARROW LESIONS: DIAGNOSIS WITHOUT BIOPSY

Routine spinal MRI can be used for bone marrow lesions detection. The most useful standard pulse sequence is T1- WI, which helps both in local and diffuse bone marrow diseases. Additional new pulse sequences, including chemical shift imaging and diffusion weighted imaging, can be used as solving-problem techniques.

Pulse Rate Variability in Emergency Physicians During Shifts: Pilot Cross-Sectional Study (Preprint)

BACKGROUND The high prevalence of physician burnout, particularly in emergency medicine, has garnered national attention in recent years. Objective means of measuring stress while at work can facilitate research into stress reduction interventions, and wearable photoplethysmography (PPG) technology has been proposed as a potential solution. However, the use of low-burden wearable biosensors to study training and clinical practice among emergency physicians (EP) remains untested. OBJECTIVE This pilot study aimed to (1) determine the feasibility of recording on-shift photoplethysmographic data from EP, (2) assess the quality of these data, and (3) calculate standard pulse rate variability (PRV) metrics from the acquired dataset and examine patterns in these variables over the course of an academic year. METHODS A total of 21 EP wore PPG biosensors on their wrists during clinical work in the emergency department during a 9-hour shift. Recordings were collected during the first quarter of the academic year, then again during the fourth quarter of the same year for comparison. The overall rate of usable data collection per time was computed. Standard pulse rate (PR) and PRV metrics from these two time points were calculated and entered into Student <italic>t</italic> tests. RESULTS More than 400 hours of data were entered into these analyses. Interpretable data were captured during 8.54% of the total recording time overall. In the fourth quarter of the academic year compared with the first quarter, there was no significant difference in median PR (75.8 vs 76.8; <italic>P</italic>=.57), mean R-R interval (0.81 vs 0.80; <italic>P</italic>=.32), SD of R-R interval (0.11 vs 0.11; <italic>P</italic>=.93), root mean square of successive difference of R-R interval (0.81 vs 0.80; <italic>P</italic>=.96), low-frequency power (3.5×103 vs 3.4×103; <italic>P</italic>=.79), high-frequency power (8.5×103 vs 8.3×103; <italic>P</italic>=.91), or low-frequency to high-frequency ratio (0.42 vs 0.41; <italic>P</italic>=.43), respectively. Power estimates for each of these tests exceeded .90. A secondary analysis of the resident-only subgroup similarly showed no significant differences over time, despite power estimates greater than .80. CONCLUSIONS Although the use of PPG biosensors to record real-time physiological data from EP while providing clinical care seems operationally feasible, this study fails to support the notion that such an approach can efficiently provide reliable estimates of metrics of interest. No significant differences in PR or PRV metrics were found at the end of the year compared with the beginning. Although these methods may offer useful applications to other domains, it may currently have limited utility in the contexts of physician training and wellness.