A prospective observation study of the dynamic monitoring of transcutaneous arterial blood oxygen saturation and carbon dioxide during bronchoscopy.

BACKGROUND AND AIMS: Because bronchoscopy is an invasive procedure, sedatives and analgesics are commonly administered, which may suppress the patient's spontaneous breathing and can lead to hypoventilation and hypoxemia. Few reports exist on the dynamic monitoring of oxygenation and ventilation during bronchoscopy. This study aimed to prospectively monitor and evaluate oxygenation and ventilation during bronchoscopy using transcutaneous arterial blood oxygen saturation and carbon dioxide. METHODS: We included patients who required pathological diagnosis using fluoroscopic bronchoscopy at our hospital between March 2021 and April 2022. Midazolam was intravenously administered to all patients as a sedative during bronchoscopy, and fentanyl was administered in addition to midazolam when necessary. A transcutaneous blood gas monitor was used to measure dynamic changes, including arterial blood partial pressure of carbon dioxide (tcPCO2), transcutaneous arterial blood oxygen saturation (SpO2), pulse rate, and perfusion index during bronchoscopy. Quantitative data of tcPCO2 and SpO2 were presented as mean ± standard deviation (SD) (min-max), while the quantitative data of midazolam plus fentanyl and midazolam alone were compared. Similarly, data on sex, smoking history, and body mass index were compared. Subgroup comparisons of the difference (Δ value) between baseline tcPCO2 at the beginning of bronchoscopy and the maximum value of tcPCO2 during the examination were performed. RESULTS: Of the 117 included cases, consecutive measurements were performed in 113 cases, with a success rate of 96.6%. Transbronchial lung biopsy was performed in 100 cases, whereas transbronchial lung cryobiopsy was performed in 17 cases. Midazolam and fentanyl were used as anesthetics during bronchoscopy in 46 cases, whereas midazolam alone was used in 67 cases. The median Δ value in the midazolam plus fentanyl and midazolam alone groups was 8.10 and 4.00 mmHg, respectively, indicating a significant difference of p < 0.005. The mean ± standard deviation of tcPCO2 in the midazolam plus fentanyl and midazolam alone groups was 44.8 ± 7.83 and 40.6 ± 4.10 mmHg, respectively. The SpO2 in the midazolam plus fentanyl and midazolam alone groups was 94.4 ± 3.37 and 96.2 ± 2.61%, respectively, with a larger SD and greater variability in the midazolam plus fentanyl group. CONCLUSION: A transcutaneous blood gas monitor is non-invasive and can easily measure the dynamic transition of CO2. Furthermore, tcPCO2 can be used to evaluate the ventilatory status during bronchoscopy easily. A transcutaneous blood gas monitor may be useful to observe regarding respiratory depression during bronchoscopy, particularly when analgesics are used.

Measures of overnight oxygen saturation to characterize sleep apnea severity and predict postoperative respiratory depression.

BACKGROUND: Sleep apnea syndrome, characterized by recurrent cessation (apnea) or reduction (hypopnea) of breathing during sleep, is a major risk factor for postoperative respiratory depression. Challenges in sleep apnea assessment have led to the proposal of alternative metrics derived from oxyhemoglobin saturation (SpO2), such as oxygen desaturation index (ODI) and percentage of cumulative sleep time spent with SpO2 below 90% (CT90), as predictors of postoperative respiratory depression. However, their performance has been limited with area under the curve of 0.60 for ODI and 0.59 for CT90. Our objective was to propose novel features from preoperative overnight SpO2 which are correlated with sleep apnea severity and predictive of postoperative respiratory depression. METHODS: Preoperative SpO2 signals from 235 surgical patients were retrospectively analyzed to derive seven features to characterize the sleep apnea severity. The features included entropy and standard deviation of SpO2 signal; below average burden characterizing the area under the average SpO2; average, standard deviation, and entropy of desaturation burdens; and overall nocturnal desaturation burden. The association between the extracted features and sleep apnea severity was assessed using Pearson correlation analysis. Logistic regression was employed to evaluate the predictive performance of the features in identifying postoperative respiratory depression. RESULTS: Our findings indicated a similar performance of the proposed features to the conventional apnea-hypopnea index (AHI) for assessing sleep apnea severity, with average area under the curve ranging from 0.77 to 0.81. Notably, entropy and standard deviation of overnight SpO2 signal and below average burden showed comparable predictive capability to AHI but with minimal computational requirements and individuals' burden, making them promising for screening purposes. Our sex-based analysis revealed that compared to entropy and standard deviation, below average burden exhibited higher sensitivity in detecting respiratory depression in women than men. CONCLUSION: This study underscores the potential of preoperative SpO2 features as alternative metrics to AHI in predicting postoperative respiratory.

Prediction of acute lung injury assessed by chest computed tomography, oxygen saturation/fraction of inspired oxygen ratio, and serum lactate dehydrogenase in patients with COVID-19.

INTRODUCTION: In treating acute hypoxemic respiratory failure (AHRF) caused by coronavirus disease 2019 (COVID-19), clinicians choose respiratory therapies such as low-flow nasal cannula oxygenation, high-flow nasal cannula oxygenation, or mechanical ventilation after assessment of the patient's condition. Chest computed tomography (CT) imaging contributes significantly to diagnosing COVID-19 pneumonia. However, the costs and potential harm to patients from radiation exposure need to be considered. This study was performed to predict the quantitative extent of COVID-19 acute lung injury using clinical indicators such as an oxygenation index and blood test results. METHODS: We analyzed data from 192 patients with COVID-19 AHRF. Multiple logistic regression was used to determine correlations between the lung infiltration volume (LIV) and other pathophysiological or biochemical laboratory parameters. RESULTS: Among 13 clinical parameters, we identified the oxygen saturation/fraction of inspired oxygen ratio (SF ratio) and serum lactate dehydrogenase (LD) concentration as factors associated with the LIV. In the binary classification of an LIV of ≥20 % or not and with the borderline LD = 2.2 × [SF ratio]-182.4, the accuracy, precision, diagnostic odds ratio, and area under the summary receiver operating characteristic curve were 0.828, 0.818, 23.400, and 0.870, respectively. CONCLUSIONS: These data suggest that acute lung injury due to COVID-19 pneumonia can be estimated using the SF ratio and LD concentration without a CT scan. These findings may provide significant clinical benefit by allowing clinicians to predict acute lung injury levels using simple, minimally invasive assessment of oxygenation capacity and biochemical blood tests.

Developing probabilistic ensemble machine learning models for home-based sleep apnea screening using overnight SpO2 data at varying data granularity.

PURPOSE: This study aims to develop sleep apnea screening models with overnight SpO2 data, and to investigate the impact of the SpO2 data granularity on model performance. METHODS: A total of 7,718 SpO2 recordings from the SHHS and MESA datasets were used. Probabilistic ensemble machine learning was employed to predict sleep apnea status at three AHI cutoff points: ≥ 5, ≥ 15, and ≥ 30 events/hour. To investigate the impact of data granularity, SpO2 data were aggregated at 30, 60, and 300 s. RESULTS: Our models demonstrated good to excellent performance on internal test, with average area under the curve (AUC) values of 0.91, 0.93, and 0.96 for cutoffs ≥ 5, ≥ 15, and ≥ 30 at data granularity of 1 s, respectively. Both sensitivity (0.76, 0.84, 0.89) and specificity (0.87, 0.86, 0.90) ranged from good to excellent across three cutoffs. Positive predictive values (PPV) ranged from excellent to fair (0.97, 0.83, 0.66), and negative predictive values (NPV) ranged from low to excellent (0.43, 0.87, 0.98). Model performance on external test slightly dropped compared to internal test, but still achieved good to excellent AUC above 0.80 across all data granularity and all the three cutoffs. Data granularity of 300 s led to a reduction in performance metrics across all cutoffs. CONCLUSION: Our models demonstrated superior performance across all three AHI cutoff thresholds compared to existing large sleep apnea screening models, even when considering varying SpO2 data granularity. However, lower data granularity was associated with decreased screening performance, indicating a need for further research in this area.

The association between high-oxygen saturation and prognosis for intracerebral hemorrhage.

BACKGROUND: Concerns about the adverse effects of excessive oxygen have grown over the years. This study investigated the relationship between high oxygen saturation and short-term prognosis of patients with spontaneous intracerebral hemorrhage (sICH) after liberal use of oxygen. METHODS: This retrospective cohort study collected data from the Medical Information Mart for Intensive Care III (MIMIC-III) database (ICU cohort) and a tertiary stroke center (general ward cohort). The data on pulse oximetry-derived oxygen saturation (SpO2) during the first 24 h in ICU and general wards were respectively extracted. RESULTS: Overall, 1117 and 372 patients were included in the ICU and general ward cohort, respectively. Among the patients from the ICU cohort, a spoon-shaped association was observed between minimum SpO2 and the risk of in-hospital mortality (non-linear P<0.0001). In comparison with minimum SpO2 of 93-97%, the minimum SpO2>97% was associated with a significantly higher risk of in-hospital mortality after adjustment for confounders. Sensitivity analysis conducted using propensity score matching did not change this significance. The same spoon-shaped association between minimum SpO2 and the risk of in-hospital mortality was also detected for the general ward cohort. In comparison with the group with 95-97% SpO2, the group with SpO2>97% showed a stronger association with, but non-significant risk for, in-hospital mortality after adjustment for confounders. The time-weighted average SpO2>97% was associated significantly with in-hospital mortality in both cohorts. CONCLUSION: Higher SpO2 (especially a minimum SpO2>97%) was unrewarding after liberal use of oxygen among patients with sICH and might even be potentially detrimental.

Eumelanin and Pheomelanin Modelling in Optical Oximetry Using Pulse Oximetry (for 540 nm and 660 nm): DC Component.

Oximetry is used to quantify the presence of oxygen in soft tissues. It can be expressed as, for example, tissue oxygen saturation (StO2), arterial oxygen saturation (SaO2) and pulsatile oxygen saturation (SpO2), among others. Non-invasive medical devices are used to estimate (SaO2). Their accuracy is compromised in individuals with highly pigmented skin. The aim of this initial work is to go back few steps into the understanding of the light absorption for the DC component in pulse oximeters, by using a mixtures model for different hypothetical scenarios of normoxia and hyperoxia. Under hypoxic states, an initial and simple multi-wavelength approach could be established to identify the impact of eumelanin (EuM) and pheomelanin (PhM), which are directly related to skin pigmentation in dark skin colour individuals. We used public spectra for water (H2O), haemoglobin (HHb), oxy-haemoglobin (HbO2), eumelanin and pheomelanin, to create 1000 possible absorption combinations. These spectra simulations were used to understand the hypothetical limits, across a 450-800 nm wavelength range. These results have outlined the maximum oxy-haemoglobin concentrations that can be detected without interfering with eumelanin and pheomelanin. This initial and simple approach helped us to understand how eumelanin and pheomelanin absorption interferes and overlaps with low oxy-haemoglobin, which is a key biomarker for oxygen quantification in pulse oximeters and other non-invasive biomedical devices.

The Development of a Measuring System for Intraoral SpO2.

Blood oxygen saturation (SpO2) is an essential indicator of a patient's general condition. However, conventional measurement methods have some issues such as time delay and interference by ambient light. Improved measurement methods must be developed, and there are no reports on intraoral measurements of SpO2 using wearable devices. Therefore, we aimed to establish an intraoral SpO2 measurement method for the first time. Twelve healthy adults participated in this study. The following steps were taken: (1) to identify the optimal measurement location, mid-perfusion index (PI) values were measured at six places on the mucosa of the maxilla, (2) to validate the optimal measurement pressure, PI values were obtained at different pressures, and (3) using the proposed mouthpiece device, SpO2 values in the oral cavity and on the finger were analyzed during breath-holding. The highest PI values were observed in the palatal gingiva of the maxillary canine teeth, with high PI values at pressures ranging from 0.3 to 0.8 N. In addition, changes in SpO2 were detected approximately 7 s faster in the oral cavity than those on the finger, which is attributed to their proximity to the heart. This study demonstrates the advantage of the oral cavity for acquiring biological information using a novel device.

Effect of Floss Band on Anaerobic Exercise and Muscle Tissue Oxygenation.

CONTEXT: Flossing is still a relatively new technique that has yielded varied results in the research literature; therefore, it requires further investigation. Previous research has shown that thigh tissue flossing might improve performance in countermovement jump, sprint time, maximum voluntary contraction, and rate of force development. DESIGN: The present study aims to investigate the effect of the floss band on performance during the Wingate test (30-WAT), muscle oxygen saturation (SpO2), and total hemoglobin in vastus lateralis. METHODS: Twenty-two students of physical education and sport (11 men and 11 women) were randomly selected to complete either the Wingate test with the application of a floss band in warm-up or the Wingate test without the use of a floss band, followed by the alternative 24 hours apart. RESULTS: Throughout the testing, the floss band did not affect performance values during the Wingate test (relative peak power, relative average power, and fatigue index). However, there was a medium to large effect difference during 1 minute prior to 30-WAT (PRE), during the 30-WAT, and 10-minute recovery (REC) in values of SpO2 and total hemoglobin. Use of floss band displayed a higher SpO2 during PRE, 30-WAT, and REC by ∼13.55%, d < 2; ∼19.06%, d = 0.89; and ∼8.55%, d = 0.59, respectively. CONCLUSION: Collectively, these findings indicate that the application of thigh flossing during warm-up has no effect on 30-WAT performance; however, SpO2 was significantly increased in all stages of testing. This could lead to potential improvement in repeated anaerobic exercise due to increased blood flow. Increased muscle oxygen saturation can also lead to improved tissue healing as oxygen supply is essential for tissue repair, wound healing, and pain management.

Comparison of Prognostic Scores for Patients with COVID-19 Presenting with Dyspnea in the Emergency Department.

BACKGROUND: Easy-to-use bedside risk assessment is crucial for patients with COVID-19 in the overcrowded emergency department (ED). OBJECTIVE: The aim of this study was to explore the prognostic ability of ratio of percutaneous oxygen saturation (SpO2) to fraction of inspired oxygen (FiO2) (S/F); ratio of SpO2/FiO2 to respiratory rate (ROX); National Early Warning Score (NEWS); quick Sequential Organ Failure Assessment (qSOFA); and confusion, respiratory rate, blood pressure, and age ≥ 65 years (CRB-65) in patients with COVID-19 presenting with dyspnea to the ED. METHODS: In this retrospective observational study, clinical and demographic details of patients with COVID-19 were obtained at ED admission. S/F, ROX, NEWS, CRB-65, and qSOFA scores were calculated at the time of ED arrival. Accuracy of these five indices to predict the need for invasive mechanical ventilation (IMV) within 48 h, intensive care unit (ICU) admission, and early (7-day) mortality were determined using receiver operating characteristic curves. RESULTS: A total of 375 patients were included in this study. Fifty patients (13.3%) required IMV within 48 h and 58 patients (15.5%) were transferred to the ICU. Seven-day mortality was 6.7% and 28-day mortality was 18.1%. Among all five scores determined from patient data on ED admission, ROX, S/F, and NEWS presented greater discriminatory performance than CRB-65 and qSOFA in predicting IMV within 48 h, ICU admission, and early mortality. CONCLUSIONS: Emergency physicians can effectively use S/F, ROX, and NEWS scores for rapid risk stratification of patients with COVID-19 infection. Moreover, from the perspective of simplicity and ease of calculation, we recommend the use of the S/F ratio.

Influence of Photoplethysmogram Signal Quality on Pulse Arrival Time during Polysomnography.

Intervals of low-quality photoplethysmogram (PPG) signals might lead to significant inaccuracies in estimation of pulse arrival time (PAT) during polysomnography (PSG) studies. While PSG is considered to be a "gold standard" test for diagnosing obstructive sleep apnea (OSA), it also enables tracking apnea-related nocturnal blood pressure fluctuations correlated with PAT. Since the electrocardiogram (ECG) is recorded synchronously with the PPG during PSG, it makes sense to use the ECG signal for PPG signal-quality assessment. (1) Objective: to develop a PPG signal-quality assessment algorithm for robust PAT estimation, and investigate the influence of signal quality on PAT during various sleep stages and events such as OSA. (2) Approach: the proposed algorithm uses R and T waves from the ECG to determine approximate locations of PPG pulse onsets. The MESA database of 2055 PSG recordings was used for this study. (3) Results: the proportions of high-quality PPG were significantly lower in apnea-related oxygen desaturation (matched-pairs rc = 0.88 and rc = 0.97, compared to OSA and hypopnea, respectively, when p < 0.001) and arousal (rc = 0.93 and rc = 0.98, when p < 0.001) than in apnea events. The significantly large effect size of interquartile ranges of PAT distributions was between low- and high-quality PPG (p < 0.001, rc = 0.98), and regular and irregular pulse waves (p < 0.001, rc = 0.74), whereas a lower quality of the PPG signal was found to be associated with a higher interquartile range of PAT across all subjects. Suggested PPG signal quality-based PAT evaluation reduced deviations (e.g., rc = 0.97, rc = 0.97, rc = 0.99 in hypopnea, oxygen desaturation, and arousal stages, respectively, when p < 0.001) and allowed obtaining statistically larger differences between different sleep stages and events. (4) Significance: the implemented algorithm has the potential to increase the robustness of PAT estimation in PSG studies related to nocturnal blood pressure monitoring.

Adoption of Transformer Neural Network to Improve the Diagnostic Performance of Oximetry for Obstructive Sleep Apnea.

Scoring polysomnography for obstructive sleep apnea diagnosis is a laborious, long, and costly process. Machine learning approaches, such as deep neural networks, can reduce scoring time and costs. However, most methods require prior filtering and preprocessing of the raw signal. Our work presents a novel method for diagnosing obstructive sleep apnea using a transformer neural network with learnable positional encoding, which outperforms existing state-of-the-art solutions. This approach has the potential to improve the diagnostic performance of oximetry for obstructive sleep apnea and reduce the time and costs associated with traditional polysomnography. Contrary to existing approaches, our approach performs annotations at one-second granularity. Allowing physicians to interpret the model's outcome. In addition, we tested different positional encoding designs as the first layer of the model, and the best results were achieved using a learnable positional encoding based on an autoencoder with structural novelty. In addition, we tried different temporal resolutions with various granularity levels from 1 to 360 s. All experiments were carried out on an independent test set from the public OSASUD dataset and showed that our approach outperforms current state-of-the-art solutions with a satisfactory AUC of 0.89, accuracy of 0.80, and F1-score of 0.79.

Comparative analysis of signal accuracy of three SpO2 monitors during motion and low perfusion conditions.

To compare pulse oximetry performance during simulated conditions of motion and low perfusion in three commercially available devices: GE HealthCare CARESCAPE ONE TruSignal SpO2 Parameter, Masimo RADICAL-7 and Medtronic Nellcor PM1000N. After IRB approval, 28 healthy adult volunteers were randomly assigned to the motion group (N = 14) or low perfusion (N = 14) group. Pulse oximeters were placed on the test and control hands using random assignment of digits 2-5. Each subject served as their own control through the series of repeated pair-wise measurements. Reference co-oximetry oxyhemoglobin (SaO2) measurements from the radial artery were also obtained in the motion group. SpO2 readings were compared between the test and control hands in both groups and to SaO2 measurements in the motion group. Accuracy was assessed through testing of accuracy root-mean squared (ARMS) and mean bias. In the simulated motion test group the overall Accuracy Root Mean Square (ARMS) versus SaO2 was 1.88 (GE), 1.79 (Masimo) and 2.40 (Nellcor), with overall mean bias of - 0.21 (Masimo), 0.45 (GE), and 0.78 (Nellcor). In the motion hand, ARMS versus SaO2 was 2.45 (GE), 3.19 (Masimo) and 4.15 (Nellcor), with overall mean bias of - 0.75 (Masimo), - 0.01 (GE), and 0.04 (Nellcor). In the low perfusion test group, ARMS versus the control hand SpO2 for low PI was 3.24 (GE), 3.48 (Nellcor) and 4.76 (Masimo), with overall bias measurements of - 0.53 (Nellcor), 0.96 (GE) and 1.76 (Masimo). Experimental results for all tested devices met pulse oximetry regulatory and testing standards requirements. Overall, SpO2 device performance across the three devices in this study was similar under both motion and low perfusion conditions. SpO2 measurement accuracy degraded for all three devices during motion as compared to non-motion. Accuracy also degraded during normal to low, very low, or ultra low perfusion and was more pronounced compared to the changes observed during simulated motion. While some statistically significant differences in individual measurements were found, the clinical relevance of these differences requires further study.

Therapeutic Effectiveness of Interferon-α2b against COVID-19 with Community-Acquired Pneumonia: The Ukrainian Experience.

Despite several targeted antiviral drugs against SARS-CoV-2 currently being available, the application of type I interferons (IFNs) still deserves attention as an alternative antiviral strategy. This study aimed to assess the therapeutic effectiveness of IFN-α in hospitalized patients with COVID-19-associated pneumonia. The prospective cohort study included 130 adult patients with coronavirus disease (COVID-19). A dose of 80,000 IU of IFN-α2b was administered daily intranasally for 10 days. Adding IFN-α2b to standard therapy reduces the length of the hospital stay by 3 days (p < 0.001). The level of CT-diagnosed lung injuries was reduced from 35% to 15% (p = 0.011) and CT injuries decreased from 50% to 15% (p = 0.017) by discharge. In the group of patients receiving IFN-α2b, the SpO2 index before and after treatment increased from 94 (92-96, Q1-Q3) to 96 (96-98, Q1-Q3) (p < 0.001), while the percentage of patients with normal saturation increased (from 33.9% to 74.6%, p < 0.05), but the level of SpO2 decreased in the low (from 52.5% to 16.9%) and very low (from 13.6% to 8.5%) categories. The addition of IFN-α2b to standard therapy has a positive effect on the course of severe COVID-19.

Airways management in SARS-COV-2 acute respiratory failure: A prospective observational multi-center study.

Objective: Few studies have reported the implications and adverse events of performing endotracheal intubation for critically ill COVID-19 patients admitted to intensive care units. The aim of the present study was to determine the adverse events related to tracheal intubation in COVID-19 patients, defined as the onset of hemodynamic instability, severe hypoxemia, and cardiac arrest. Setting: Tertiary care medical hospitals, dual-centre study performed in Northern Italy from November 2020 to May 2021. Patients: Adult patients with positive SARS-CoV-2 PCR test, admitted for respiratory failure and need of advanced invasive airways management. Interventions: Endotracheal Intubation Adverse Events. Main variables of interests: The primary endpoint was to determine the occurrence of at least 1 of the following events within 30 minutes from the start of the intubation procedure and to describe the types of major adverse peri-intubation events: severe hypoxemia defined as an oxygen saturation as measured by pulse-oximetry <80%; hemodynamic instability defined as a SBP 65 mmHg recoded at least once or SBP < 90 mmHg for 30 minutes, a new requirement or increase of vasopressors, fluid bolus >15 mL/kg to maintain the target blood pressure; cardiac arrest. Results: Among 142 patients, 73.94% experienced at least one major adverse peri-intubation event. The predominant event was cardiovascular instability, observed in 65.49% of all patients undergoing emergency intubation, followed by severe hypoxemia (43.54%). 2.82% of the patients had a cardiac arrest. Conclusion: In this study of intubation practices in critically ill patients with COVID-19, major adverse peri-intubation events were frequent. Clinical Trial registration: www.clinicaltrials.gov identifier: NCT04909476.

Objetivo: Pocos estudios han informado las implicaciones y los eventos adversos de realizar una intubación endotraqueal para pacientes críticos con COVID-19 ingresados ​​en unidades de cuidados intensivos. El objetivo del presente estudio fue determinar los eventos adversos relacionados con la intubación traqueal en pacientes con COVID-19, definidos como la aparición de inestabilidad hemodinámica, hipoxemia severa y paro cardíaco. Ámbito: Hospitales médicos de atención terciaria, estudio de doble centro realizado en el norte de Italia desde noviembre de 2020 hasta mayo de 2021. Pacientes: Pacientes adultos con prueba PCR SARS-CoV-2 positiva, ingresados por insuficiencia respiratoria y necesidad de manejo avanzado de vías aéreas invasivas. Intervenciones: Eventos adversos de la intubación endotraqueal. Principales variables de interés: El punto final primario fue determinar la ocurrencia de al menos 1 de los siguientes eventos dentro de los 30 minutos posteriores al inicio del procedimiento de intubación y describir los tipos de eventos adversos periintubación mayores. : hipoxemia severa definida como una saturación de oxígeno medida por pulsioximetría <80%; inestabilidad hemodinámica definida como PAS 65 mmHg registrada al menos una vez o PAS < 90 mmHg durante 30 minutos, nuevo requerimiento o aumento de vasopresores, bolo de líquidos > 15 mL/kg para mantener la presión arterial objetivo; paro cardiaco. Resultados: Entre 142 pacientes, el 73,94% experimentó al menos un evento periintubación adverso importante. El evento predominante fue la inestabilidad cardiovascular, observada en el 65,49% de todos los pacientes sometidos a intubación de urgencia, seguido de la hipoxemia severa (43,54%). El 2,82% de los pacientes tuvo un paro cardíaco. Conclusión: En este estudio de prácticas de intubación en pacientes críticos con COVID-19, los eventos adversos periintubación mayores fueron frecuentes. Registro de ensayos clínicos: www.clinicaltrials.gov identificador: NCT04909476.

Nasal obstruction during the growth period modulates the Wnt/ß-catenin pathway and brain-derived neurotrophic factor production in association with tyrosine kinase receptor B mRNA reduction in mouse hippocampus.

There is accumulating evidence that nasal obstruction induces high-level brain dysfunction, including memory and learning deficits. We previously demonstrated that unilateral nasal obstruction (UNO) during the growth period increases the expression of brain-derived neurotrophic factor (BDNF). The expression of BDNF is regulated by the Wnt/ß-Catenin pathway, which is linked to neuronal differentiation, proliferation, and maintenance. However, little is known about whether Wnt3a protein expression could be an index for modulations analyses in the Wnt/ß-Catenin pathway caused by UNO during the growth period. This study aimed to investigate the effects of UNO during the growth period on the Wnt/ß-Catenin pathway in the hippocampus using combined behavioural, biochemical, and histological approaches. Male BALB/C mice were randomly divided into the control (CONT; n = 6) and experimental (UNO; n = 6) groups. Blood oxygen saturation (SpO2 ) levels were measured, and a passive avoidance test was performed in mice aged 15 weeks. Brain tissues were subjected to immunohistochemistry, real-time reverse transcription-polymerase chain reaction, and western blot analysis. Compared with control mice, UNO mice had lower SpO2 levels and exhibited memory/learning impairments during behavioural testing. Moreover, Wnt3a protein, BDNF mRNA, and tyrosine kinase receptor B (TrkB) mRNA expression levels were significantly lower in the hippocampus in the UNO group than in the CONT group. Our findings suggested that UNO during the growth period appeared to modulate the hippocampal Wnt/ß-catenin pathway and BDNF production in association with TrkB mRNA reduction, thereby resulting in memory and learning impairments.

Seven days of ischemic preconditioning augments hypoxic exercise ventilation and muscle oxygenation in recreationally trained males.

This investigation sought to assess whether single or repeated bouts of ischemic preconditioning (IPC) could improve oxyhemoglobin saturation ([Formula: see text]) and/or attenuate reductions in muscle tissue saturation index (TSI) during submaximal hypoxic exercise. Fifteen healthy young men completed submaximal graded exercise under four experimental conditions: 1) normoxia (NORM), 2) hypoxia (HYP) [oxygen fraction of inspired air ([Formula: see text]) = 0.14, ∼3,200 m], 3) hypoxia preceded by a single session of IPC (IPC1-HYP), and 4) hypoxia preceded by seven sessions of IPC, one a day for 7 consecutive days (IPC7-HYP). IPC7-HYP heightened minute ventilation (V̇e) at 80% HYP peak cycling power output (Wpeak) (+10.47 ± 3.35 L·min-1, P = 0.006), compared with HYP, as a function of increased breathing frequency. Both IPC1-HYP (+0.17 ± 0.04 L·min-1, P < 0.001) and IPC7-HYP (+0.16 ± 0.04 L·min-1, P < 0.001) elicited greater oxygen consumption (V̇o2) across exercise intensities compared with NORM, whereas V̇o2 was unchanged with HYP alone. [Formula: see text] was unchanged by either IPC condition at any exercise intensity, yet the reduction of muscle TSI during resting hypoxic exposure was attenuated by IPC7-HYP (+9.9 ± 3.6%, P = 0.040) compared with HYP, likely as a function of reduced local oxygen extraction. Considering all exercise intensities, IPC7-HYP attenuated reductions of TSI with HYP (+6.4 ± 1.8%, P = 0.001). Seven days of IPC heightens ventilation, posing a threat to ventilatory efficiency, during high-intensity submaximal hypoxic exercise and attenuates reductions in hypoxic resting and exercise muscle oxygenation in healthy young men. A single session of IPC may be capable of modulating hypoxic ventilation; however, our present population was unable to demonstrate this with certainty.

The role of a noninvasive index 'Spo2/ Fio2' in predicting mortality among patients with COVID-19 pneumonia.

INTRODUCTION: Noninvasive risk assessment is crucial in patients with COVID-19 in emergency department. Since limited data is known about the role of noninvasive parameters, we aimed to evaluate the role of a noninvasive parameter 'SpO2/FiO2' in independently predicting 30-day mortality in patients with COVID-19 and its prognostic utility in combination with a noninvasive score 'CRB-65'. METHODS: A retrospective study was performed in a tertiary training and research hospital, which included 272 patients with COVID-19 pneumonia diagnosed with polymerase chain reaction in emergency department. Data on characteristics, vital signs, and laboratory parameters were recorded from electronic medical records. The primary outcome of the study was 30-day mortality, and we assessed the discriminative ability of SpO2/FiO2 in predicting mortality in patients with COVID-19 pneumonia and its prognostic utility in combination with conventional pneumonia risk assessment scores. RESULTS: Multivariate analysis revealed that only SpO2/FiO2 level was found to be an independent parameter associated with 30-day mortality (OR:0.98, 95% CI: 0.98-0.99, p = 0.003). PSI and CURB-65 were found to be better scores than CRB-65 in predicting 30-day mortality (AUC: 0.79 vs 0.72, p = 0.04; AUC: 0.76 vs 0.72, p = 0.01 respectively). Both SpO2/FiO2 combined with CRB-65 and SpO2/FiO2 combined with CURB-65 have good discriminative ability and seemed to be more favorable than PSI in predicting 30-days mortality (AUC: 0.83 vs 0.75; AUC: 0.84 vs 0.75), however no significant difference was found (p = 0.21 and p = 0.06, respectively). CONCLUSION: SpO2/FiO2 is a promising index in predicting mortality. Addition of SpO2/FiO2 to CRB-65 improved the role of CRB-65 alone, however it performed similar to PSI. The combined noninvasive model of SpO2/FiO2 and CRB-65 may help physicians quickly stratify COVID-19 patients on admission, which is expected to be particularly important in hospitals still stressed by pandemic volumes.

Performance of the new SmartCardia wireless, wearable oximeter: a comparison with arterial SaO2 in healthy volunteers.

BACKGROUND: Our goal was to evaluate the performance of a new wearable arm located pulse oximeter. METHODS: Twelve volunteers were monitored with three pulse oximeters and underwent desaturation to 70% SaO2. We compared the accuracy of SpO2 reading from the SmartCardia system with SpO2 using two well established devices (Masimo and Nellcor) as reference. Oximetry was performed at different level of oxygen saturation varying from 70 to 100%. Bias, ARMS and precision were evaluated using Bland-Altman plots. RESULTS: The mean (SD) differences between SaO2 compared to SpO2 and the devices were as follows: SaO2 versus Masimo 2,12 ± 1,01% (95% CI 1,45 to 2,79), SaO2 versus Nellcor 0,78 ± 0,58% (95% CI - 0,29 to 1,65) and SaO2 versus SmartCardia 0,42 ± 0,24% (95% CI - 0,64 to 1,46). The bias between SmartCardia, Masimo, Nellcor devices and SaO2 was 0.16 (95% CI 0.05 to 0.33) and LoA (level of agreements) 2.96 (95% CI - 2,68 to 2,89) for SmartCardia, 2,02 (95% CI 1,49 to 2,54) and LoA - 6 to 11 for Masimo, and 0,76 (95% CI 0,5 to - 1) and LoA - 3,5 to 5,0 for Nellcor. ARMS for the 70-100% SaO2 range was 1,4 for SmartCardia, 5,0 for Masimo and 2,31 for Nellcor. CONCLUSIONS: The new wireless SmartCardia SpO2 measurement system demonstrated in-line results, bias, ARMS and precision in healthy volunteers, when compared with the gold standard SaO2 and with two well established systems, Masimo and Nellcor. TRIAL REGISTRATION: The present trial was prospectively registered at UCSF record (registration number:10-00437), on March 8, 2021.

Evaluation of the effects on SpO2 of N95 mask (FFP2) on dental health care providers: a cross-sectional observational study.

OBJECTIVE: The purpose of this cross-sectional observational study was to evaluate the effects of SpO2 in a sample of dental health care providers who wear a N95 mask or Filtering Face Piece (FFP2) for four consecutive hours, measured by a pulse oximeter before donning the mask and again after four hours of work and to offer some strategies to minimize discomfort and improve communication with their patients while wearing the mask. MATERIALS AND METHODS: A 17-item questionnaire was sent via Google Drive to various practitioners in Italy and the USA. A sample of 162 questionnaires were returned from dentists, orthodontists, dental hygienists and dental assistants who committed to wearing a FFP2 for 4 consecutive hours during a work day and then measuring the oxygen saturation by way of a pulse oximeter before and after the 4 working hours. The final analysis was performer on 147 viable questionnaires returned. The sample was composed of 62 males and 85 females with an average age of 42.9 ± 12.0 years. RESULTS: For the entire sample population, the baseline saturation was 98.6 ± 1.2 and, after four hours of mask wearing, there was a significant decrease in oxygen saturation to 97.0 ± 2.9 (p < 0.01). No statistical differences in SpO2 were found across specialties or across types of procedures performed during the 4 h. Heart rates were not significantly different before and after the 4 h in all categories. The 3 most frequent reported complaints were: fatigue (64%), headache (36%) and external ear pain (31%). The most common additional personal protective equipment (PPE) was a mask shield (78%) and those who wore the mask continuously reported more communication difficulty with patients, compared with those who took the mask off more often, in fact, 64% of the subjects reported that using the mask influenced their communication with their patients. Based on the results of the questionnaire, a list of breathing and vocal folds health strategies was devised and proposed, along with strategies to augment communication with patients. CONCLUSIONS: This study highlights a significant decrease in oxygen saturation after only 4 h of work (except for smokers) while wearing a FFP2, and confirms the widespread symptoms of fatigue, headache and pain behind the ears that dental professionals experience. But it also highlighted how mask wearing impaired communication with patients and wearing additional masks and a facial shield may add to those communications difficulties. This aspect and the need for better communication can lead the operators to remove the mask to improve breathing and communication, thus putting themselves at a risk of infection. Of all the aspects explored in this study, the most interesting was indeed the impact on fatigue and communication and the strategies proposed in this article can easily be implemented to reduce headache and fatigue by improving breathing efficiency and by aiding communication while donning a mask by improving voice quality and by using augmentative communication tools.

Evaluation of Intraoperative End-Tidal Carbon Dioxide Change Relates to Length Hospitalisation in Peridiaphragmatic Surgery: A Pilot Study.

Intraoperative evaluation is deeply changed using many new tools, both invasive and non-invasive. Peripheral oxygen saturation percentage (SpO2) is the more reliable method for a non-invasive monitoring of patient's blood oxygen concentration. Capnography (using end-tidal CO2 (EtCO2)) evaluation is an immediate and continuous non-invasive monitoring of carbon dioxide (CO2) in the breathing that provides important information on circulatory status and ventilation.Aim of this study is to perform a preliminary analysis of oxygen change during surgery exploring its possible influence on post-operative evolution. METHODS AND RESULTS: Intraoperative evaluation of SpO2 and EtCO2 was performed. Change in each parameter was categorised as 1 point for each five-point variation from baseline value (∆SpO2 as 1 point for each 5%, ∆EtCO2 as 1 point for each 5 mmHg). For each patient, the length of stay (LOS) in the intensive care unit (ICU), total hospitalisation, duration of intervention, surgical risk and complications were recorded. RESULTS: We analysed 93 consecutive patients (43 males and 40 females, aged 66.35 ± 9.79 years) that underwent peridiaphragmatic surgery. Forty patients (48.19%) presented complications after surgery. There was no statistically significant difference in age, duration of intervention and length of stay in ICU between complicated and non-complicated patients. As expected, patients with complications present an increased hospitalisation time compared to uncomplicated cases (14.69 ± 11.41 days vs 10.70 ± 6.28 days; p < 0.05). ∆EtCO2 was significantly increased (p < 0.05) in complicated compared to non-complicated. No differences were found in ∆SpO2 between the two groups. Considering the whole population, ∆EtCO2 presents a significant direct correlation to surgical risk, hospitalisation and duration of intervention. CONCLUSION: ∆EtCO2 may be related to possible complications after surgery and hospitalisation. An important comparison between SpO2 and EtCO2 and strict monitoring with an intraoperative arterial blood gas (ABG) sample during the main steps of surgery could bring some essential information to understand oxygen changes in intra- and post-operative evolution. However, a further validation analysis is needed before the approach can be used extensively in daily clinical settings.