Low oxygen saturation and mortality in an adult cohort: the Tromsø study

Quantitative ultrasound and photoacoustic assessments of red blood cell aggregation in the human radial artery

We develop concurrent US and photoacoustic (PA) imaging to characterize structural/physiological impact of in-vivo red blood cell (RBC) aggregation. PA images at 700/800/900 nm were collected from the radial arteries of 12 participants across age groups (20 s/30 s/40 s) alongside US images (21 MHz, VevoLAZR). RBC aggregate size was estimated from US-derived structure-factor-size-estimation (D SFSE) and PA-derived spectral-slope (SS), along with oxygen saturation (sO2). At peak systole (PS), D SFSE PS and SSPS approximated 1 RBC and -0.1 dB/MHz, respectively, across all ages, with sO2 PS values of 97.1 %, 94.7 %, and 93.0 % for each group. At end diastole (ED), D SFSE ED, SSED and sO2 ED values were 2.6, 3.4, and 4.7 RBCs; -0.7, -0.9, and -1.2 dB/MHz; and 98.7 %, 97.2 %, and 96.7 %, respectively. Differences between SSED and SSPS (δSS) and sO2 ED and sO2 PS (δsO2) increased with age, indicating aging-related increases in DSFSE and δSS, as well as decreases in sO2 PS and sO2 ED.

Facility-measured nocturnal hypoxemia and sleep among adults with long COVID versus age- and sex-matched healthy adults: a preliminary observational study

Study Objectives

Persistent post-acute sequelae of SARS-CoV-2 infection, i.e. long COVID, impacts multiple organ systems. While lower blood oxygen is expected when SARS-CoV-2 infects the lungs, hypoxia without pulmonary symptoms may continue after the acute phase. Ventilation and blood oxygen are more vulnerable during sleep, but nocturnal hypoxemia hasn't been studied in people with long COVID in a facility setting using gold-standard polysomnography (PSG).

Methods

We conducted an observational study with 50 participants (25 long COVID, 25 age-sex-matched healthy controls) using in-laboratory overnight PSG. We calculated the average SpO2, average SpO2 after removing desaturations, the respiratory rate in different sleep periods, and the hypoxic costs using all desaturations.

Results

We found that average SpO2 was lower in participants with long COVID: 1.0% lower after sleep onset (p = .004) and 0.7% lower during REM (p = .002); average SpO2 after removing desaturations was also lower in participants with long COVID: 1.3% lower after sleep onset (p = .002), 0.9% lower during REM (p = .0004), and 1.4% lower during NREM (p = .003); and respiratory rate was 1.4/minute higher in participants with long COVID during REM (p = .005). There were no significant differences in SpO2 and respiratory rate before sleep onset, the within-participant change from before to after sleep onset, or hypoxic costs.

Conclusions

The results suggest that long COVID had a persistent lower nocturnal blood oxygen saturation, and support the need for a large-scale study of nocturnal hypoxemia in people with long COVID compared to the general population.

Associations of Short-Term Ozone Exposure With Hypoxia and Arterial Stiffness

BACKGROUND

Epidemiological studies reported associations between ozone (O3) exposure and cardiovascular diseases, yet the biological mechanisms remain underexplored. Hypoxia is a shared pathogenesis of O3-associated diseases; therefore, we hypothesized that O3 exposure may induce changes in hypoxia-related markers, leading to adverse cardiovascular effects.

OBJECTIVES

This study aimed to investigate associations of short-term O3 exposure with hypoxic biomarkers and arterial stiffness.

METHODS

We conducted a panel study involving 210 young healthy residents in 2 cities at different altitudes on the Qinghai-Tibetan Plateau in China, where O3 concentrations are high and particulate pollution is low. Participants underwent 4 repeated visits to assess ambient O3 exposure levels, hypoxic biomarkers, and arterial stiffness. We applied linear mixed-effects models to assess the associations of O3 exposure (lag1 to lag1-7 days) with hypoxic biomarkers and arterial stiffness, adjusted for confounders. Mediation analyses explored the hypoxia's role in O3-related arterial stiffness changes. We further examined effect modification by residence altitude and the robustness of results by including PM2.5 (particulate matter ≤2.5 μm in aerodynamic diameter) or NO2 in 2-pollutant models.

RESULTS

O3 exposure 1 to 7 days before visits was significantly associated with changes in multiple hypoxic biomarkers. A 10-ppb increase in O3 exposure was linked to significant decreases in oxygen saturation (SpO2) and increases in red blood cell count (RBC), hemoglobin concentration, and hematocrit, with maximum changes by -0.42%, 0.92%, 0.97%, and 1.92%, respectively. Laboratory analysis of mRNA and protein markers consistently indicated that O3 exposure activated the hypoxia-inducible factor 1 (HIF-1) signaling pathway. Additionally, a 10-ppb increase in O3 corresponded to a 1.04% to 1.33% increase in carotid-femoral pulse wave velocity (cfPWV), indicating increased arterial stiffness. RBC, hemoglobin concentration, and hematocrit increases significantly mediated the O3-cfPWV association, whereas the SpO2 reduction had an insignificant mediating effect. Associations of O3 with hypoxic biomarkers varied by altitude. The higher altitude group showed delayed associations with SpO₂ and HIF-1 expression but stronger associations with RBC indices. These associations remained robust after adjusting for copollutants.

CONCLUSIONS

O3 exposure may reduce oxygen availability, prompting compensatory increases in red blood cells and hemoglobin, which exacerbate arterial stiffening. These findings provide new insights into the mechanisms underlying O3-induced cardiovascular injury.

Association of nocturnal oxygen saturation with coronary artery calcification: cross-sectional evidence from the population-based SESSA study among Japanese men

OBJECTIVE

We investigated the associations of nocturnal oxygen saturation (SpO2) with prevalence of coronary artery calcification (CAC) and its level of burden, and whether the associations differ by obesity and mediate through diabetes mellitus (DM), dyslipidaemia and hypertension.

DESIGN

Observational study.

SETTING

Kusatsu, Shiga.

PARTICIPANTS

We analysed data from 510 Japanese men (aged 46-76 years) with no history of myocardial infarction.

PRIMARY AND SECONDARY OUTCOMES

Mean SpO2, minimum SpO2 and oxygen desaturation index (ODI) were measured using overnight pulse oximetry (primary exposures), while CAC was assessed using CT. Prevalence of CAC (>0) and its burden (CAC 0, >0-100, >100-400 and>400) were evaluated as outcomes. Body mass index≥25.0 kg/m2 defined as obesity.

RESULTS

Mean±SD age was 66.7±7.2 years. The prevalence of CAC was 64.7% (CAC scores>0-100, 31.4%; >100-400, 20.0% and>400, 13.3%). In multivariable binary logistic regression, the OR and 95% CI for the prevalence of CAC were 1.25 (1.02 to 1.53) per 1-SD decrement in mean SpO2 and 1.25 (1.01 to 1.55) per 1-SD increment in ODI. The associations lost their significance while further adjusted for DM and dyslipidaemia. Similar trends were observed for the level of CAC burden in multivariable ordinal logistic regression. Obesity did not show significant interaction with SpO2 on CAC. In mediation analysis, the OR (95% CI) for natural indirect effect; percentage mediated through dyslipidaemia in association of 1-SD decrement in mean SpO2 with prevalence of CAC were 1.06 (1.01 to 1.10); 25.4%. These estimates for mediation through DM and dyslipidaemia for 1-SD increment in ODI in the associations were 1.07 (1.01 to 1.12); 29.6% and 1.04 (1.00 to 1.08); 17.5%, respectively.

CONCLUSIONS

Lower mean SpO2 and higher ODI are associated with CAC among Japanese men, independent of age, lifestyle factors and obesity. The associations became non-significant after adjusting for diabetes and dyslipidaemia, but were mediated through these factors.

Caspase-11 and NLRP3 exacerbate systemic Klebsiella infection through reducing mitochondrial ROS production

Introduction

Klebsiella pneumoniae is a Gram-negative bacterium and the third most commonly isolated microorganism in blood cultures from septic patients. Despite extensive research, the mechanisms underlying K. pneumoniae-induced sepsis and its pathogenesis remain unclear. Acute respiratory failure is a leading cause of mortality in systemic K. pneumoniae infections, highlighting the need to better understand the host immune response and bacterial clearance mechanisms.

Method

To investigate the impact of K. pneumoniae infection on organ function and immune response, we utilized a systemic infection model through intraperitoneal injection in mice. Bacterial loads in key organs were quantified, and lung injury was assessed. Survival analysis was performed in wild-type (WT) and gene deficient mice. Mitochondrial damage and reactive oxygen species (ROS) production, as well as cytokine levels were measured in macrophages isolated from these mice to evaluate their contribution to bacterial clearance capacity.

Results

Our findings demonstrate that K. pneumoniae systemic infection results in severe lung injury and significant bacterial accumulation in multiple organs, with the highest burden in the lungs. Deficiency of caspase-11 or NLRP3 led to prolonged survival, a reduction in pulmonary bacterial load, increased blood oxygen levels, and decreased IL-6 levels in the lungs compared to WT controls. Furthermore, caspase-11- and NLRP3-deficient macrophages exhibited elevated mitochondrial ROS production in response to K. pneumoniae, which correlated with more effective bacterial clearance.

Discussion

These results suggest that caspase-11 and NLRP3 contribute to K. pneumoniae-induced sepsis by impairing mitochondrial function and reducing ROS production in macrophages, thereby compromising bacterial clearance. The observed reduction in lung injury and increased survival in caspase-11- and NLRP3-deficient mice indicate that targeting these pathways may offer potential therapeutic strategies to improve host defense against systemic K. pneumoniae infection.

Evaluation of Postanesthesia Handoff Checklist on Patient Outcomes in an Adult Postanesthesia Care Unit

PURPOSE

The use of handoff communication tools, such as checklists, has been shown to improve communication and decrease the omission of critical patient care information. However, the effect these tools have on patient outcomes has not been investigated. After successfully implementing a handoff checklist in an adult postanesthesia care unit, patient outcomes were retrospectively measured before and after the implementation.

DESIGN

Retrospective chart review.

METHODS

Seven hundred and ninety-one prechecklist patients in September 2017 were compared to 828 postchecklist patients in September 2018. Pain scores, oxygen saturation, and end-tidal CO2 readings were collected for postanesthesia care unit patients in both groups.

FINDINGS

Postchecklist patients exhibited less severe pain (30.8% vs 42.4%) and fewer desaturation episodes (36.4% vs 44.8%). Time to rescue for both did not show a significant difference.

CONCLUSIONS

This retrospective comparison showed an improvement in measurable patient outcomes in the immediate postoperative period after the implementation of a handoff communication tool. More research is needed to determine the direct correlation between handoff tool use and measurable patient outcomes.

Final diagnoses and mortality rates in ambulance patients administered nebulized β2-agonists bronchodilators

To assess final diagnoses and mortality rates (30 day and 1 year) in patients treated with the inhaled bronchodilator salbutamol by ambulance personnel, and to establish its role as an identifier of moderate to severe respiratory distress in the prehospital phase of treatment. In a descriptive retrospective observational study, patients experiencing respiratory distress and treated with inhaled bronchodilators, specifically salbutamol, in the prehospital setting within the Central Denmark Region during 2018-2019 were included. The study included 6318 ambulance transports, comprising 3686 cases of acute exacerbation of chronic obstructive pulmonary disease (AECOPD), 234 with community-acquired pneumonia (CAP), 320 with heart disease (HD), 233 adults with asthma, 1674 with various other primary ICD-10 diagnoses (other ≥ 18 years), and 171 patients under 18 years. The 30 day mortality rate for all patients was 10.7% (95% CI 9.8-11.6), with zero deaths within 30 days among adults with asthma and those under 18. Excluding low mortality groups, AECOPD patients had the lowest 30 day mortality at 10.2% (95% CI 9.1-11.3), and HD patients the highest at 15.3% (95% CI 10.6-19.9). The 1-year overall mortality rate increased to 32.1% (95% CI 30.2-34.0), with mortality staying low for asthma and under-18 groups, while differences between other groups lessened and became insignificant. Patients requiring inhaled bronchodilator treatment in ambulances exhibit notably high mortality rates at 30 days and 1 year, except for those with asthma or under 18. The need for prehospital bronchodilators could serve as a clear and unmistakable marker for moderate to severe respiratory distress, enabling early intervention.

Long-Term Clinical, Radiological, and Mortality Outcomes Following Pneumonitis in Nonsmall Cell Lung Cancer Patients Receiving Immune Checkpoint Inhibitors: A Retrospective Analysis

AIMS

Despite known short-term mortality risk of immune checkpoint inhibitor (ICI) pneumonitis, its impact on 1-year mortality, long-term pulmonary function, symptom persistence, and radiological resolution remains unclear.

METHODS

We retrospectively analyzed 71 nonsmall cell lung cancer (NSCLC) patients treated with anti-PD(L)1 monoclonal antibodies between 2018-2021, who developed pneumonitis. Clinical and demographic covariates were collected from electronic medical record. Cox regression assessed associations with mortality, while logistic regression evaluated associations with persistent symptoms, hypoxemia, and radiological resolution.

RESULTS

Steroid-refractory pneumonitis (hazard ratio [HR] = 15.1, 95% confidence interval [95% CI]:3.9-57.8, P < .0001) was associated with higher 1-year mortality compared to steroid-responsive cases. However, steroid-resistant (odds ratio [OR] = 1.4, 95% CI: 0.4-5.1, P = .58) and steroid-dependent (OR = 0.4, 95% CI: 0.1-1.2, P = .08) pneumonitis were not. Nonadenocarcinoma histology (OR = 6.7, 95% CI: 1.6-46.6, P = .01), grade 3+ pneumonitis (OR = 4.6, 95% CI: 1.3-22.7, P = .03), and partial radiological resolution (OR = 6.3, 95% CI: 1.8-23.8, P = .004) were linked to increased pulmonary symptoms after pneumonitis resolution. Grade 3+ pneumonitis (OR = 8.1, 95% CI: 2.3-31.5, P = .001) and partial radiological resolution (OR = 5.45, 95% CI: 1.29-37.7, P = .03) associated with residual hypoxemia. Nonadenocarcinoma histology (OR = 3.6, 95% CI: 1.01-17.6, P = .06) and pretreatment ILAs (OR = 4.8, 95% CI: 1.14-33.09, P = .05) were associated with partial radiological resolution.

CONCLUSIONS

Steroid refractory pneumonitis increases 1-year mortality in NSCLC patients. Pretreatment ILAs may signal predisposition to fibrosis-related outcomes, seen as partial resolution, which in turn is associated with postresolution symptoms and residual hypoxemia. These findings offer insights for identifying patients at risk of adverse outcomes post-pneumonitis resolution.

Crocetin Delays Brain and Body Aging by Increasing Cellular Energy Levels in Aged C57BL/6J Mice

Aging is usually accompanied by mitochondrial dysfunction, reduced energy levels, and cell death in the brain and other tissues. Mitochondria play a crucial role in maintaining cellular energy through oxidative phosphorylation (OXPHOS). However, OXPHOS is impaired as the mitochondrial oxygen supply decreases with age. We explored whether pharmacologically increased oxygen diffusion by crocetin can restore OXPHOS and help delay the aging of the brain and other vital organs. We found that aged mice treated with crocetin for four months displayed significantly improved memory behavior, neuromuscular coordination, and ATP and NAD+ levels in the brain and other vital organs, leading to an increased median life span. The transcriptomic analysis of hippocampi from crocetin-treated mice revealed that enhanced brain energy level was caused by the upregulation of genes linked to OXPHOS, and their expression was close to that in young mice. The chronic treatment of aged astrocytes also showed improved mitochondrial membrane potential and energy state of the cells. Moreover, chronic treatment with crocetin did not cause any oxidative stress. Our data suggest that restoring OXPHOS and the normal energy state of the cell can delay aging and enhance longevity. Therefore, molecules such as crocetin should be further explored to treat age-related diseases.

Recent Advances in the Wearable Devices for Monitoring and Management of Heart Failure

Heart failure (HF) is an acute and degenerative condition with high morbidity and mortality rates. Early diagnosis and treatment of HF can significantly enhance patient outcomes through admission and readmission reduction and improve quality of life. Being a progressive condition, the continuous monitoring of vital signs and symptoms of HF patients to identify any deterioration and to customize treatment regimens can be beneficial to the management of this disease. Recent breakthroughs in wearable technology have revolutionized the landscape of HF management. Despite the potential benefits, the integration of wearable devices into HF management requires careful consideration of technical, clinical, and ethical challenges, such as performance, regulatory requirements and data privacy. This review summarizes the current evidence on the role of wearable devices in heart failure monitoring and management, and discusses the challenges and opportunities in the field.

Timely ICU Outcome Prediction Utilizing Stochastic Signal Analysis and Machine Learning Techniques with Readily Available Vital Sign Data

The ICU is a specialized hospital department that offers critical care to patients at high risk. The massive burden of ICU-requiring care requires accurate and timely ICU outcome predictions for alleviating the economic and healthcare burdens imposed by critical care needs. Existing research faces challenges such as feature extraction difficulties, low accuracy, and resource-intensive features. Some studies have explored deep learning models that utilize raw clinical inputs. However, these models are considered non-interpretable black boxes, which prevents their wide application. The objective of the study is to develop a new method using stochastic signal analysis and machine learning techniques to effectively extract features with strong predictive power from ICU patients' real-time time series of vital signs for accurate and timely ICU outcome prediction. The results show the proposed method extracted meaningful features and outperforms baseline methods, including APACHE IV (AUC = 0.750), deep learning-based models (AUC = 0.732, 0.712, 0.698, 0.722), and statistical feature classification methods (AUC = 0.765) by a large margin (AUC = 0.869). The proposed method has clinical, management, and administrative implications since it enables healthcare professionals to identify deviations from prognostications timely and accurately and, therefore, to conduct proper interventions.

SARS-CoV-2 Infection Positively Correlates with Hyperglycemia and Inflammatory Markers in COVID-19 Patients: A Clinical Research Study

Diabetes mellitus (DM) is a common comorbidity in COVID-19 subjects. Hyperglycemia at hospital admission identified as a major risk factor and is responsible for poor prognosis. Hematological and inflammatory parameters have been recognized as predictive markers of severity in COVID-19. In this clinical study, we aimed to assess the impact of hyperglycemia at hospital admission on hematological and several inflammatory parameters in COVID-19 patients. A total of 550 COVID-19 subjects were primarily categorized into two major groups (normoglycemic and hyperglycemic) based on random blood sugar levels. On the first day of hospitalization, subjects' oxygen saturation, random blood sugar, hematological variables, and inflammatory parameters were recorded. The hyperglycemic group exhibited higher levels of serum ferritin, total leukocyte count (TLC), lactate dehydrogenase (LDH), neutrophil count, and neutrophil-to-lymphocyte ratio (NLR). In contrast, oxygen saturation and lymphocyte count were lower compared to the normoglycemic group. Significantly elevated levels of hematological variables (TLC, neutrophil count, NLR) and inflammatory parameters (serum ferritin) were observed in the hyperglycemic group. Among inflammatory parameters, only serum ferritin levels showed statistical significance. This study supports the clinical association between hyperglycemia and an increased severity of COVID-19. Consequently, the identification of these parameters is a crucial and valuable prognostic indicator for assessing disease severity in hyperglycemic subjects.

Outcomes of coronary artery bypass grafting (CABG) in patients with OSA-COPD overlap syndrome versus COPD alone: an analysis of US Nationwide Inpatient Sample

BACKGROUND

Obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) are associated with unfavorable outcomes following coronary artery bypass grafting (CABG). The purpose of this study was to compare in-hospital outcomes of patients with COPD alone versus OSA-COPD overlap after CABG.

METHODS

Data of adults ≥ 18 years old with COPD who received elective CABG between 2005 and 2018 were extracted from the US Nationwide Inpatient Sample (NIS). Patients were divided into two groups: with OSA-COPD overlap and COPD alone. Propensity score matching (PSM) was employed to balance the between-group characteristics. Logistic and linear regression analyses determined the associations between study variables and inpatient outcomes.

RESULTS

After PSM, data of 2,439 patients with OSA-COPD overlap and 9,756 with COPD alone were analyzed. After adjustment, OSA-COPD overlap was associated with a significantly increased risk of overall postoperative complications (adjusted odd ratio [aOR] = 1.12, 95% confidence interval [CI]: 95% CI: 1.01-1.24), respiratory failure/prolonged mechanical ventilation (aOR = 1.27, 95%CI: 1.14-1.41), and non-routine discharge (aOR = 1.16, 95%CI: 1.03-1.29), and AKI (aOR = 1.14, 95% CI: 1.00-1.29). Patients with OSA-COPD overlap had a lower risk of in-hospital mortality (adjusted odd ratio [aOR] = 0.53, 95% CI: 0.35-0.81) than those with COPD only. Pneumonia or postoperative atrial fibrillation (AF) risks were not significantly different between the 2 groups. Stratified analyses revealed that, compared to COPD alone, OSA-COPD overlap was associated with increased respiratory failure/prolonged mechanical ventilation risks among patients ≥ 60 years, and both obese and non-obese subgroups. In addition, OSA-COPD overlap was associated with increased risk of AKI among the older and obese subgroups.

CONCLUSION

In US adults who undergo CABG, compared to COPD alone, those with OSA-COPD are at higher risks of non-routine discharge, AKI, and respiratory failure/prolonged mechanical ventilation, but a lower in-hospital mortality. No increased risk of AF was noted.

Effect of face masks on dyspnea perception, cardiopulmonary parameters, and facial temperature in healthy adults

Respiratory droplets, naturally produced during expiration, can transmit pathogens from infected individuals. Wearing a face mask is crucial to prevent such transmission, yet the perception of dyspnea and uncomfortable breathing remains a common concern, particularly during epidemics. The aim of this study was to investigate the impact of face mask use on the perception of dyspnea, cardiopulmonary parameters, and facial temperature during physical activity. A randomized crossover study was conducted on healthy adults at a physiology laboratory located in the Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia, in November 2022. Participants underwent five stages of physical exercise tests based on the Bruce Protocol under three conditions: without any face mask (control), wearing a surgical mask, and an N95 mask, forming the study's main groups. Dyspnea perception (measured by the Modified Borg Dyspnea Scale), cardiopulmonary parameters (heart rate, oxygen saturation, respiratory rate, blood pressure, and mean arterial pressure) and facial temperature were measured before the exercise test (pre-workout), at the end of stage 1, 2, 3, 4, 5, and after the whole exercise test (post-workout). A two-way repeated measures ANOVA was conducted, considering two factors: the type of mask (control, surgical mask, N95 mask) and the various stages of the exercise test. A total of 36 healthy adults were included in the study. We found that dyspnea perception was much worse in the N95 mask group, particularly during vigorous exercise. There was no significant difference between groups in cardiopulmonary parameters. However, participants wearing N95 had a greater supralabial temperature than those wearing surgical masks or no mask at all. It is recommended to undertake a more in-depth evaluation of cardiopulmonary physiological measures.

Nocturnal oxygen saturation is associated with all-cause mortality: a community-based study

STUDY OBJECTIVES

Observational studies have demonstrated the association between the single-point measurement of oxygen saturation (SpO2) level and mortality in the general population. This study aimed to evaluate whether nocturnal SpO2 level could predict all-cause mortality in a community-based population.

METHODS

The study samples were obtained from the Sleep Heart Health Study, which included 2,280 men and 2,606 women (mean age, 63.8 ± 11.1 years). A pulse oximeter based on overnight in-home polysomnography was used to monitor SpO2 levels during total sleep time (SpO2-TOTAL). Multivariable Cox proportional hazards analysis was performed to examine the association between nocturnal SpO2 and all-cause mortality.

RESULTS

During the follow-up period of 10.7 ± 3.0 years, 1,110 (22.7%) people died. After adjusting for confounding factors, multivariable Cox regression analysis showed that the average SpO2-TOTAL (hazard ratio [HR] 0.93; 95% confidence interval [CI] 0.90-0.96, P < .001) was associated with all-cause mortality. These findings remained stable in individuals with low and high apnea-hypopnea index levels. Additionally, maximum SpO2-TOTAL (HR, 0.91; 95% CI, 0.87-0.96; P = .001) and minimum SpO2-TOTAL (HR, 0.98; 95% CI, 0.97-0.99; P = .001) could predict all-cause mortality. A significant association between nocturnal hypoxemia and all-cause mortality was also observed.

CONCLUSIONS

Our findings highlight the importance of monitoring nocturnal SpO2 level and improving hypoxemia in the general populations.

CITATION

Yan B, Gao Y, Zhang Z, Shi T, Chen Q. Nocturnal oxygen saturation is associated with all-cause mortality: a community-based study. J Clin Sleep Med. 2024;20(2):229-235.

Outcome of Poisoning and Associated Factors Among Patients Admitted at Referral Hospitals in Northwest Ethiopia, 2022: A Multicenter Retrospective Study

Background

Poisonings are the most common reason for visiting emergency departments and hospitals globally. Poisoning-related mortalities increase instantly, and it is a principal public health problem in Ethiopia. Hence, understanding the treatment outcome and identifying the associated factors is necessary to reduce poisoning-related mortality.

Objective

To assess outcome of poisoning and associated factors among patients admitted to Referral Hospitals in Northwest Ethiopia, 2022.

Methods

An institutional-based retrospective cross-sectional study was conducted in Western Amhara referral hospitals from June 2019 to May 2022. A total of 400 medical charts were reviewed. A stratified sampling technique was used. The data were entered into Epi Info version 7.2.1.0 and exported to SPSS version 25.0 software for analysis. Multivariable binary logistic regression analysis was used to determine factors associated with the outcome of poisoning.

Results

The mortality rate of poisoning was 18% (95% CI: 14.4-22.1). Being rural dwellers (AOR=2.65, 95% CI: 1.07-6.63), being unconscious (AOR=4.86, 95% CI: 1.89-12.48), not treated in triage area (AOR=4.64, 95% CI: 1.608-13.407), transport by Bajaj (AOR=6.78, 95% CI: 1.86-24.73), spo2 <95% (AOR=4.42, 95% CI: 1.19-10.78), and stayed >48 hours in the hospital (AOR=0.08, 95% CI: 0.02-0.36) were significantly associated with a mortality of poisoning.

Conclusion

The mortality rate from poisoning was considerably high. Residence, level of consciousness, treatment at the triage area, mode of arrival, Spo2, and prolonged hospital stay were significantly associated. All stakeholders should focus on planning and improving care for patients with poisoning. Improving ambulance service in rural areas and providing treatment at the triage area for all patients are recommended.

Nighttime Sleep and Respiratory Disturbances in Individuals Receiving Methadone to Treat Opioid Use Disorder

ABSTRACT

Opioids are a leading cause of drug overdose deaths in the United States. Methadone used as medication for opioid use disorder (MOUD) reduces drug cravings and promotes abstinence. However, individuals in methadone-based MOUD treatment commonly report subjective sleep complaints and are at risk for respiratory depression from opioids. We investigated nighttime sleep and respiratory function in eight individuals (six women, two men; ages 31-68 years) in their first 90 days of methadone-based MOUD treatment. Participants underwent overnight cardiorespiratory polysomnography. Sleep and respiratory variables were characterized with descriptive statistics for comparison to reference data from similarly aged healthy adults. Although participants spent 8.1 ± 0.3 hours (mean ± SD ) in bed, their total sleep time was only 6.8 ± 1.3 hours. They exhibited longer sleep latency and intermittent wakefulness. Sleep structure was irregular, with disrupted sleep cycles. Participants also displayed a decreased amount of N1 sleep and an increased amount of N3 sleep, compared with reference data. Participants showed respiratory depression, with an average apnea-hypopnea index of 16.5 ± 8.9 events per hour. Central sleep apneas comprised 69.1% ± 20.9% of the respiratory events. A Cheyne-Stokes-like breathing pattern, consisting of 30-second cycles of three central sleep apneas, was observed in 75% of participants. Our results suggest that individuals early in methadone-based MOUD treatment experience disordered sleep and respiratory disturbances. Such nighttime physiological changes may have serious long-term health consequences and contribute to unintended overdose rates. Identifying and treating MOUD individuals with sleep apnea could reduce risk of death.

Pulse oximetry values from 33,080 participants in the Apple Heart & Movement Study

Wearable devices that include pulse oximetry (SpO₂) sensing afford the opportunity to capture oxygen saturation measurements from large cohorts under naturalistic conditions. We report here a cross-sectional analysis of 72 million SpO₂ values collected from 33,080 individual participants in the Apple Heart and Movement Study, stratified by age, sex, body mass index (BMI), home altitude, and other demographic variables. Measurements aggregated by hour of day into 24-h SpO₂ profiles exhibit similar circadian patterns for all demographic groups, being approximately sinusoidal with nadir near midnight local time, zenith near noon local time, and mean 0.8% lower saturation during overnight hours. Using SpO₂ measurements averaged for each subject into mean nocturnal and daytime SpO₂ values, we employ multivariate ordinary least squares regression to quantify population-level trends according to demographic factors. For the full cohort, regression coefficients obtained from models fit to daytime SpO₂ are in close quantitative agreement with the corresponding values from published reference models for awake arterial oxygen saturation measured under controlled laboratory conditions. Regression models stratified by sex reveal significantly different age- and BMI-dependent SpO₂ trends for females compared with males, although constant terms and regression coefficients for altitude do not differ between sexes. Incorporating categorical variables encoding self-reported race/ethnicity into the full-cohort regression models identifies small but statistically significant differences in daytime SpO₂ (largest coefficient corresponding to 0.13% lower SpO₂, for Hispanic study participants compared to White participants), but no significant differences between groups for nocturnal SpO₂. Additional stratified analysis comparing regression models fit independently to subjects in each race/ethnicity group is suggestive of small differences in age- and sex-dependent trends, but indicates no significant difference in constant terms between any race/ethnicity groups for either daytime or nocturnal SpO₂. The large diverse study population and study design employing automated background SpO₂ measurements spanning the full 24-h circadian cycle enables the establishment of healthy population reference trends outside of clinical settings.

Sleep Architecture and Sleep-Related Breathing Disorders of Seafarers on Board Merchant Ships: A Polysomnographic Pilot Field Study on the High Seas

As seafarers are assumed to have an increased risk profile for sleep-related breathing disorders, this cross-sectional observational study measured (a) the feasibility and quality of polysomnography (PSG) on board merchant ships, (b) sleep macro- and microarchitecture, (c) sleep-related breathing disorders, such as obstructive sleep apnea (OSA), using the apnea-hypopnea index (AHI), and (d) subjective and objective sleepiness using the Epworth Sleepiness Scale (ESS) and pupillometry. Measurements were carried out on two container ships and a bulk carrier. A total of 19 out of 73 male seafarers participated. The PSG's signal qualities and impedances were comparable to those in a sleep laboratory without unusual artifacts. Compared to the normal population, seafarers had a lower total sleep time, a shift of deep sleep phases in favor of light sleep phases as well as an increased arousal index. Additionally, 73.7% of the seafarers were diagnosed with at least mild OSA (AHI ≥ 5) and 15.8% with severe OSA (AHI ≥ 30). In general, seafarers slept in the supine position with a remarkable frequency of breathing cessations. A total of 61.1% of the seafarers had increased subjective daytime sleepiness (ESS > 5). Pupillometry results for objective sleepiness revealed a mean relative pupillary unrest index (rPUI) of 1.2 (SD 0.7) in both occupational groups. In addition, significantly poorer objective sleep quality was found among the watchkeepers. A need for action with regard to poor sleep quality and daytime sleepiness of seafarers on board is indicated. A slightly increased prevalence of OSA among seafarers is likely.

Prediction of survival time after terminal extubation: the balance between critical care unit utilization and hospice medicine in the COVID-19 pandemic era

BACKGROUND

We established 1-h and 1-day survival models after terminal extubation to optimize ventilator use and achieve a balance between critical care for COVID-19 and hospice medicine.

METHODS

Data were obtained from patients with end-of-life status at terminal extubation from 2015 to 2020. The associations between APACHE II scores and parameters with survival time were analyzed. Parameters with a p-value ≤ 0.2 in univariate analysis were included in multivariate models. Cox proportional hazards regression analysis was used for the multivariate analysis of survival time at 1 h and 1 day.

RESULTS

Of the 140 enrolled patients, 76 (54.3%) died within 1 h and 35 (25%) survived beyond 24 h. No spontaneous breathing trial (SBT) within the past 24 h, minute ventilation (MV) ≥ 12 L/min, and APACHE II score ≥ 25 were associated with shorter survival in the 1 h regression model. Lower MV, SpO2 ≥ 96% and SBT were related to longer survival in the 1-day model. Hospice medications did not influence survival time.

CONCLUSION

An APACHE II score of ≥ 25 at 1 h and SpO2 ≥ 96% at 1 day were strong predictors of disposition of patients to intensivists. These factors can help to objectively tailor pathways for post-extubation transition and rapidly allocate intensive care unit resources without sacrificing the quality of palliative care in the era of COVID-19. Trial registration They study was retrospectively registered. IRB No.: 202101929B0.

Exploring the Association between Oxygen Concentration and Life Expectancy in China: A Quantitative Analysis

The aim of this study was to investigate and quantify the association between oxygen concentration and life expectancy. The data from 34 provinces and 39 municipalities were included in all analyses. Bayesian regression modeling with spatial-specific random effects was used to quantify the impact of oxygen concentration (measured as partial pressure of oxygen) on life expectancy, adjusting for other potential confounding factors. We used hierarchical cluster analysis to group the provinces according to disease burden and analyzed the oxygen levels and the characteristics of causes of death between the clusters. The Bayesian regression analysis showed that the life expectancy at the provincial level increased by 0.15 (95% CI: 0.10-0.19) years, while at the municipal level, it increased by 0.17 (95% CI: 0.12-0.22) years, with each additional unit (mmHg) of oxygen concentration, after controlling for potential confounding factors. Three clusters were identified in the hierarchical cluster analysis, which were characterized by different oxygen concentrations, and the years of life lost from causes potentially related to hypoxia were statistically significantly different between the clusters. A positive correlation was found between oxygen concentration and life expectancy in China. The differences in causes of death and oxygen levels in the provincial clusters suggested that oxygen concentration may be an important factor in life expectancy when mediated by diseases that are potentially related to hypoxia.

Impact of sarcopenia on postoperative pulmonary complications after gastric cancer surgery: A retrospective cohort study

Background

Few studies have investigated the relationship between sarcopenia and postoperative pulmonary complications (PPCs) after gastric cancer surgery. This study aimed to explore the impact of sarcopenia on PPCs in patients who had undergone gastric cancer surgery.

Methods

We included patients who underwent a transabdominal radical gastrectomy between June 2016 and October 2020. Patients were divided into two groups according to the median prevalence rate of lumbar triplane skeletal muscle index (L3 SMI): sarcopenia group (≤37.5% percentile in male and female group) and non-sarcopenia group (>37.5% percentile in male and female group). Baseline characteristics, intraoperative and postoperative conditions, pulmonary complications, and overall complications were compared between the two groups. The primary outcome was the incidence of PPCs. The secondary outcomes were overall postoperative complications and length of stay (LOS).

Results

Among the 143 patients included, 50 had sarcopenia and 93 had not. Compared to the non-sarcopenia group, the sarcopenia group had a higher the incidence of PPCs (22.0% vs. 8.6%, P = 0.024). The incidence of overall postoperative complications in the sarcopenia group was higher than that in the non-sarcopenia group (36.00% vs. 20.43%, P = 0.043). There was no significant difference in the LOS between the two groups.

Conclusions

Our research indicates that sarcopenia, preoperative comorbidities, and longer duration of intraoperative oxygen saturation <95% were risk factors for PPCs. Sarcopenia is an independent risk factor for postoperative complications. Given that our results provided a correlation rather than causation, future prospective randomized trials are needed to confirm the relationship between sarcopenia and prognosis.

Biomass using tribal women exhibited respiratory symptoms, hypertensive risks and abnormal pulmonary function

In rural areas of developing countries, solid fuels are still widely used for cooking, heating, and lighting purposes. This study investigates the effects of household air pollutants (HAPs) exposure on the occurrence of respiratory symptoms, blood pressure, and lung function. In this study, we randomly selected 123 (83 biomass and 40 clean fuel user) subjects to assess the impact of smoke generated from solid biomass fuel by assessing their health status along with the ventilation pattern of the kitchens and living rooms. HAPs (PM10, PM2.5, and CO) and different health parameters were measured along with monitoring of self-reported health symptoms for a consecutive period of eight months. Results revealed that the concentration of CO, PM2.5, and PM10 were found highest in biomass using households. Higher odds of the upper respiratory symptoms, runny nose (OR: 4.08, 95% CI: 1.22-22.14, p < 0.03), nasal congestion (OR: 9.07, 95% CI: 1.39-97.89, p < 0.01) and the odds of the lower respiratory symptoms like wheezing (OR: 1.62, 95% CI: 1.23-10.94, p < 0.01), breathlessness (OR: 4.44, 95% CI: 1.3-14.75, p < 0.01), chest tightness (OR: 4.89, 95% CI: 1.23-22.14, p < 0.03) and dry cough (OR: 3.661, 95% CI: 1.05-12.25, p < 0.04) were significantly higher in biomass fuel user. Similarly higher systolic (+11.41 mmHg), higher diastolic pressure (+3.3 mmHg), higher pulse pressure (+8.11 mmHg), and a 6 mmHg higher mean arterial pressure among biomass fuel using tribal women. The risk of hypertension was significantly (p < 0.03) higher (OR: 3.04; 95% CI: 1.18-7.89) among solid biomass fuel users. The lung abnormality was recorded 28.91% (OR: 5.02, 95% CI: 1.50 to 16.56, p < 0.01) among biomass fuel user. Finally, it is suggested that the use of efficient cookstoves, increase in cross ventilation, and cleaner fuel are urgently needed to curb the pollution load.

Lower Blood Oxygen Saturation is Associated With Microvascular Complications in Individuals With Type 1 Diabetes

CONTEXT

Blood oxygen saturation (SpO2) is lower in type 1 diabetes (T1D) compared with nondiabetic controls. Hypoxia (low tissue oxygenation) is thought to be a risk factor for progression of diabetic complications, but it is unknown whether hypoxemia (low SpO2) is associated with diabetic complications.

OBJECTIVE

To test if hypoxemia is associated with presence of diabetic complications in T1D.

DESIGN, SETTING, AND METHODS

Cross-sectional study in persons with T1D divided by a previously suggested threshold in low (<96%) and high (≥96%) SpO2, measured in the supine position with pulse oximetry. Complications included albuminuria (2 of 3 consecutive measurements ≥30 mg/g), any diabetic retinopathy, neuropathy, and history of cardiovascular disease (CVD). Odds ratios were adjusted for age, diabetes duration, sex, smoking, physical activity, body mass index, systolic blood pressure, and blood hemoglobin.

RESULTS

We included 659 persons, 23 (3.5%) with low and 636 (96.5%) with high SpO2. In total, 151 (23%) had albuminuria, 233 (36%) had retinopathy, 231 (35%) had neuropathy, and 72 (11%) had CVD. The adjusted odds ratio (95% CI, P value) for low vs high SpO2 was 3.4 (1.3-8.7, P = 0.01) for albuminuria, 2.8 (1.0-7.5, P = 0.04) for retinopathy, 5.8 (1.8-18.6, P < 0.01) for neuropathy, and nonsignificant for CVD (0.6 [0.2-2.4, P = 0.51]).

CONCLUSIONS

SpO2 below 96% was associated with increased presence of albuminuria, retinopathy, and neuropathy in T1D, but not with CVD. Whether hypoxemia could be a target of intervention to prevent progression in microvascular disease in type 1 diabetes should be investigated.

Blood oxygen saturation is lower in persons with pre-diabetes and screen-detected diabetes compared with non-diabetic individuals: A population-based study of the Lolland-Falster Health Study cohort

Aims

Low blood oxygen saturation is associated with increased mortality and persons with diabetes have sub-clinical hypoxemia. We aimed to confirm the presence of sub-clinical hypoxemia in pre-diabetes, screen-detected diabetes and known diabetes.

Methods

Pre-diabetes was defined as hemoglobin A1C (HbA1C) ≥ 42 mmol/mol and <48 mmol/mol; known diabetes as history or treatment of diabetes; screen-detected diabetes as no history or treatment of diabetes and HbA1C ≥ 48 mmol/mol. Blood oxygen saturation was measured with pulse oximetry. Urine albumin-to creatinine ratio (UACR) was measured on a single spot urine.

Results

The study included 829 adults (≥18 years) with diabetes (713 (86%) with known diabetes; 116 (14%) with screen-detected diabetes) and 12,747 without diabetes (11,981 (94%) healthy controls; 766 (6%) with pre-diabetes). Mean (95% CI) blood oxygen saturation was 96.3% (96.3% to 96.4%) in diabetes which was lower than in non-diabetes [97.3% (97.2-97.3%)] after adjustment for age, gender, and smoking (p < 0.001), but significance was lost after adjustment for BMI (p = 0.25). Sub-groups with pre-diabetes and screen-detected diabetes had lower blood oxygen saturations than healthy controls (p-values < 0.01). Lower blood oxygen saturation was associated with higher UACR.

Conclusions

Persons with pre-diabetes and screen-detected diabetes have sub-clinical hypoxemia, which is associated with albuminuria.

Accuracy of Oxygen Saturation Measurements in Patients with Obesity Undergoing Bariatric Surgery

BACKGROUND

We aimed to determine the magnitude, direction, and influencing factors of the concordance between arterial oxygen saturation (SaO₂) and peripheral capillary oxygen saturation (SpO₂) in patients with obesity undergoing bariatric surgery, supporting the measurement of SaO₂ and SpO₂ in key populations.

METHODS

Patients with obesity undergoing bariatric surgery from 2017 to 2020 were included. Preoperative SpO₂ and SaO₂ were collected. Linear correlation and multiple linear regression analyses were performed to characterize the relationships between body mass index (BMI), age, and sex with pulse oximetry and arterial blood gas (ABG) parameters. Bland-Altman analysis was applied to determine the concordance between SpO₂ and SaO₂ and the limits of this concordance.

RESULTS

A total of 134 patients with obesity undergoing bariatric surgery were enrolled. SaO₂ was negatively associated with BMI (p < 0.0001) and age (p = 0.006), and SpO₂ was negatively associated with BMI (p = 0.021) but not with age. SpO₂ overestimated SaO₂ in 91% of patients with a bias of 2.05%. This bias increased by 203% in hypoxemic patients compared with nonhypoxemic patients (p < 0.0001). The bias was 1.3-fold higher (p = 0.023) in patients with a high obesity surgery mortality risk score (OS-MRS) than in those with low or intermediate scores.

CONCLUSION

Compared with SpO₂, preoperative SaO₂ can more accurately reflect the real oxygen saturation in patients with obesity undergoing bariatric surgery, especially for those with BMI ≥ 40 kg/m², age ≥ 40 years, and high OS-MRS. ABG analysis can provide a more reliable basis for accurate and timely monitoring, ensuring the perioperative safety of susceptible patients.

Effects of an individualized and progressive multicomponent exercise program on blood pressure, cardiorespiratory fitness, and body composition in long-term care residents: Randomized controlled trial

This study analyzed the effects of an individualized and progressive multicomponent exercise program on blood pressure, cardiorespiratory fitness, and body composition in long-term care residents. This was a single-blind, multicenter, randomized controlled trial performed in 10 long-term care settings and involved 112 participants. Participants were randomly assigned to a control group or an intervention group. The control group participated in routine activities; the intervention group participated in a six-month individualized and progressive multicomponent exercise program focused on strength, balance, and walking recommendations. The intervention group maintained peak VO₂, oxygen saturation, and resting heart rate, while the control group showed a significant decrease in peak VO₂ and oxygen saturation and an increase in resting heart rate throughout the six-month period. Individualized and progressive multicomponent exercise programs comprising strength, balance, and walking recommendations appear to be effective in preventing cardiorespiratory fitness decline in older adults living in long-term care settings.

Disparities in oxygen saturation and hypoxic burden levels in obstructive sleep apnea patient's response to oral appliance treatment

Background

Oxygen saturation indices show a strong correlation with long‐term health outcomes. Nonetheless, evidence on the relationship between reduction in respiratory events and increase in oxygenation levels following oral appliance (OA) treatment is scarce.

Objectives

To verify the relationship between reduction in the apnoea‐hypopnoea index (AHI) and oxygen saturation levels following OA treatment, we have conducted an evaluation of polysomnography (PSG) and clinical parameters associated with the improvement of oxygen desaturation.

Methods

OSA patients (n = 48) who received an OA and had pre‐ and post‐treatment PSG were classified into three responder groups according to the change in AHI and min O₂ post‐treatment: responder_AHIonly (decrease in AHI of ≥50% but increase in min O₂ level of <4% or decrease); responder_MinO2only (increase in min O₂ level of ≥4% but decrease in AHI <50% or increase) and responder_Congruous (decrease in AHI of ≥50% and increase in min O₂ level of ≥4%). Various demographic and PSG variables were statistically compared among groups.

Results

There were 26 (54.17%) responder_AHIonly, 9 (18.75%) responder_MinO2only and 13 (27.08%) responder_Congruous. Pre‐treatment min O₂ was significantly lower in responder_MinO2only. A higher pre‐treatment min O₂ showed a significant correlation with a smaller amount of change in mean O₂ (r = −.486) and min O₂ (r = −.764) with treatment. Pre‐treatment min O₂ showed the strongest ability to predict those who would show a ≥4% min O₂ increase following treatment.

Conclusion

Certain patients do not show sufficient decrease in hypoxaemia in spite of the improvement in AHI. Pre‐treatment min O₂ should be considered in OA treatment planning regarding its close relation to improvements in oxygenation levels with treatment.

Learning Predictive and Interpretable Timeseries Summaries from ICU Data

Machine learning models that utilize patient data across time (rather than just the most recent measurements) have increased performance for many risk stratification tasks in the intensive care unit. However, many of these models and their learned representations are complex and therefore difficult for clinicians to interpret, creating challenges for validation. Our work proposes a new procedure to learn summaries of clinical timeseries that are both predictive and easily understood by humans. Specifically, our summaries consist of simple and intuitive functions of clinical data (e.g. "falling mean arterial pressure"). Our learned summaries outperform traditional interpretable model classes and achieve performance comparable to state-of-the-art deep learning models on an in-hospital mortality classification task.

Partial pressure of oxygen level at admission as a predictor of postoperative pneumonia after hip fracture surgery in a geriatric population: a retrospective cohort study

OBJECTIVE

To identify whether the partial pressure of oxygen in arterial blood (PaO₂) level at admission is an independent risk factor as a prognostic biomarker to predict postoperative pneumonia (POP) in the geriatric population who have undergone hip fracture surgical repair at our hospital.

DESIGN

A retrospective cohort study.

SETTING

This is a retrospective chart review of POP after hip fracture surgery in China.

PARTICIPANTS

In training cohort, patients aged ≥65 years who had hip fracture surgery between 1 January 2018 and 30 November 2019. In the validation cohort, a series of patients who underwent hip fracture surgery between 1 January 2020 and 28 February 2020.

INTERVENTIONS

Receiver operating characteristic (ROC) analysis was used to obtain the area under the ROC curve (AUC) and cut-off values of PaO₂ to predict POP. A binomial logistic regression model was used to identify potential risk factors for POP by analysing demographic distribution factors, laboratory results, preoperative comorbidities and surgical factors. Then the regression model was validated using an independent cohort.

RESULTS

In the training cohort, ROC curves were generated to compare the predictive performance of PaO₂ for the occurrence of POP, and the area under the receiver operating characteristic curve (AUC) was 0.653 (95% CI 0.577 to 0.729, p<0.0001), with sensitivity and specificity values of 60.0% and 63.8%, respectively. The cut-off value of the PaO₂ for POP was 72.5 mm Hg. Binary logistic regression analysis revealed that hypoxaemia (PaO₂ <72.5 mm Hg) at hospital admission (OR=3.000, 95% CI 1.629 to 5.528; p<0.0001) was independent risk factors associated with POP after hip fracture surgery. In the validation cohort, PaO₂ had a predictive effect for POP (AUC 0.71, 95% CI 0.541 to 0.891).

CONCLUSIONS

The current study revealed that the PaO₂ level at hospital admission is a simple and widely available biomarker predictor of POP after hip fracture surgery in elderly patients.

Which criteria is a better predictor of ICU admission in trauma patients? An artificial neural network approach

PURPOSE

One of the most critical concerns in the intensive care unit (ICU) section is identifying the best criteria for entering patients to this part. This study aimed to predict the best compatible criteria for entering trauma patients in the ICU section.

METHOD

The present study was a historical cohort study. The data were collected from 2448 trauma patients referring to Shahid Rajaee Hospital between January 2015 and January 2017 in Shiraz, Iran. The artificial neural network (ANN) models with cross-validation and logistic regression (LR) with a backward method was used for data analysis. The final analysis was performed on a total of 958 patients who were transferred to the ICU section.

RESULTS

Based on the present results, the motor component of the GCS score at each cutoff point had the highest importance. The results also showed better performance for the AUC and accuracy rate for ANN compared with LR.

CONCLUSION

The most critical indicators in predicting the optimal use of ICU services in this study were the Motor component of the GCS. Results revealed that the ANN had a better performance than the LR in predicting the main outcomes of the traumatic patients in both the accuracy and AUC index. Trauma section surgeons and ICU specialists will benefit from this study's results and can assist them in making decisions to predict the patient outcomes before entering the ICU.

COVID-19-The impact of variable and "low normal" pulse oximetry scores on Oximetry@Home services and clinical pathways: Confounding variables?

COVID‐19 Oximetry@Home services have been commissioned nationally. This allows higher‐risk patients with mild COVID‐19 symptoms to remain at home, being supplied with a Pulse Oximeter to measure their oxygen saturation (SpO₂) two to three times daily for two weeks. Patients record their readings manually or electronically which are monitored by a clinical team. Clinical decisions, using an algorithm, are based on SpO₂ readings in a narrow range with 1–2 point changes potentially affecting care. In this article, we discussed the problem that multiple factors affect SpO₂ readings, and that some “normal” individuals will have “low‐normal” scores at the threshold of clinical management, without any known respiratory problem. We discuss the potential magnitude of this problem based on the associated literature and consider how this will have an impact on the use of the Oximetry@home services, potentially partially confounding their purpose; to reduce face‐to‐face medical care.

[Pulse oximetry: Role in the COVID-19 patient at home]

La COVID-19 se comporta como una enfermedad heterogénea. Algunos pacientes pueden presentar hipoxemia sin disnea durante su evolución (hipoxemia silente). La pulsioximetría juega un papel crucial en la detección de la hipoxemia en estos pacientes, especialmente cuando permanecen en su domicilio. Pacientes con niveles de SpO₂ ≤ 92% o desaturaciónes ≥ 3% tras el ejercicio precisan de ingreso hospitalario. Los descensos progresivos de la saturación que alcancen niveles SpO₂ < 96% precisan de valoración clínica estricta (estudio radiológico, analítica sanguínea) para lo que será enviado a un centro sanitario.

In vivo photoacoustic assessment of the oxygen saturation changes in the human radial artery: a preliminary study associated with age

SIGNIFICANCE

We demonstrate the potential of probing the sO2 change under blood flow in vivo using photoacoustic (PA) imaging and sheds light on the complex relationship between RBC aggregation and oxygen delivery.

AIM

To conduct in vivo assessments of the sO2 in the radial artery of healthy volunteers and simultaneously probe the relation between the sO2 and hemodynamic behavior such as red blood cell (RBC) aggregation.

APPROACH

The effects of PA-based measurements of blood hemodynamics were studied as a function of the subjects' age (20s, 30s, and 40s). The pulsatile blood flow in the human radial artery of 12 healthy subjects was imaged in the 700 to 900 nm optical wavelength range using a linear array-based PA system.

RESULTS

The PA power when blood velocity is minimum (Pamax) was larger than the one attained at maximum blood velocity (Pamin), consistent with predictions based on the cyclical variation of RBC aggregation during pulsatile flow. The difference between Pamin and Pamax at 800 nm (ΔPa800) increased with age (1.7, 2.2, and 2.6 dB for age group of 20s, 30s, and 40s, respectively). The sO2 computed from Pamax was larger than the one from Pamin.

CONCLUSIONS

The ΔPa800 increased with participant age. The ΔPa800 metric could be a surrogate of noninvasively monitoring the age-induced changes in RBC aggregation. The sO2 change during a cycle of pulsatile blood flow also increased with age, demonstrating that RBC aggregation can affect the sO2 change.

Circulating and tissue biomarkers as predictors of bromine gas inhalation

The threat from deliberate or accidental exposure to halogen gases is increasing, as is their industrial applications and use as chemical warfare agents. Biomarkers that can identify halogen exposure, diagnose victims of exposure or predict injury severity, and enable appropriate treatment are lacking. We conducted these studies to determine and validate biomarkers of bromine (Br₂ ) toxicity and correlate the symptoms and the extent of cardiopulmonary injuries. Unanesthetized rats were exposed to Br₂ and monitored noninvasively for clinical scores and pulse oximetry. Animals were euthanized and grouped at various time intervals to assess brominated fatty acid (BFA) content in the plasma, lung, and heart using mass spectrometry. Bronchoalveolar lavage fluid (BALF) protein content was used to assess pulmonary injury. Cardiac troponin I (cTnI) was assessed in the plasma to evaluate cardiac injury. The blood, lung, and cardiac tissue BFA content significantly correlated with the clinical scores, tissue oxygenation, heart rate, and cardiopulmonary injury parameters. Total (free + esterified) bromostearic acid levels correlated with lung injury, as indicated by BALF protein content, and free bromostearic acid levels correlated with plasma cTnI levels. Thus, BFAs and cardiac injury biomarkers can identify Br₂ exposure and predict the severity of organ damage.

The prevalence of hypoxemia among pediatric and adult patients presenting to healthcare facilities in low- and middle-income countries: protocol for a systematic review and meta-analysis

BACKGROUND

Hypoxemia is a severe condition associated with high rates of mortality, particularly in low- and middle-income countries (LMICs) with poor access to oxygen therapy. Despite its clinical significance, there have been few studies to describe the burden of hypoxemia. Thus, the primary objective of this study is to systematically describe the prevalence of hypoxemia among pediatric and adult patients in low- and middle-income countries.

METHODS/DESIGN

Standard systematic review methods will be used. Bibliographic databases (MEDLINE, EMBASE, CINAHL) will be searched from 1998 onwards. The search strategy aims to identify studies that have measured peripheral blood oxygen saturation (SpO₂) in children and adults presenting to health facilities in LMICs. Studies will be included if oxygen saturation measurements by pulse oximetry were measured. No studies will be excluded based on study design though patients recruited from intensive care units and post-operative care will be excluded. The primary outcome is the prevalence of hypoxemia on presentation to the healthcare facility. We define hypoxemia on the basis of SpO₂ measurements, and use a threshold of SpO₂ less than 90% at sea level though allow for a lower threshold for studies conducted at higher altitude and where justified. Standardized tools will be used to extract data on number of patients with SpO₂ measurements, number of patients with hypoxemia, patient population characteristics, and study characteristics. Quality of the included studies will be assessed using the "Checklist for Prevalence Studies" developed by the Joanna Briggs Institute. If there are enough studies to do so, we will conduct meta-analysis using a random effects model to estimate prevalence of hypoxemia and conduct subgroup analyses by age and disease groups.

DISCUSSION

Hypoxemia is a critical condition and understanding the burden of hypoxemia may support decision-making in LMICs to deploy pulse oximeters and oxygen treatments more efficiently to address diseases and patient populations with the highest burden. Previous studies on hypoxemia prevalence have focused too narrowly on a few diseases or specific patient populations (e.g., pneumonia in children under five) whereas any effort to improve access to oxygen requires understanding of the potential demand for oxygen for all diseases and population groups. Governments, UN agencies, donors, and NGOs are investing strongly to improve oxygen systems in LMICs. Effective oxygen system planning requires estimation of oxygen need, informed by robust data on hypoxemia prevalence and admission patterns at all the levels of the health system. This study aims to fill that gap by providing comprehensive estimates of hypoxemia prevalence.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019136622.

Sleep-disordered breathing and comorbidities: role of the upper airway and craniofacial skeleton

Obstructive sleep-disordered breathing (SDB), which includes primary snoring through to obstructive sleep apnea syndrome (OSAS), may cause compromise of respiratory gas exchange during sleep, related to transient upper airway narrowing disrupting ventilation, and causing oxyhemoglobin desaturation and poor sleep quality. SDB is common in chronic disorders and has significant implications for health. With prevalence rates globally increasing, this condition is causing a substantial burden on health care costs. Certain populations, including people with sickle cell disease (SCD), exhibit a greater prevalence of OSAS. A review of the literature provides the available normal polysomnography and oximetry data for reference and documents the structural upper airway differences between those with and without OSAS, as well as between ethnicities and disease states. There may be differences in craniofacial development due to atypical growth trajectories or extramedullary hematopoiesis in anemias such as SCD. Studies involving MRI of the upper airway illustrated that OSAS populations tend to have a greater amount of lymphoid tissue, smaller airways, and smaller lower facial skeletons from measurements of the mandible and linear mental spine to clivus. Understanding the potential relationship between these anatomical landmarks and OSAS could help to stratify treatments, guiding choice towards those which most effectively resolve the obstruction. OSAS is relatively common in SCD populations, with hypoxia as a key manifestation, and sequelae including increased risk of stroke. Combatting any structural defects with appropriate interventions could reduce hypoxic exposure and consequently reduce the risk of comorbidities in those with SDB, warranting early treatment interventions.

Prediction of early postoperative desaturation in extreme older patients after spinal anesthesia for femur fracture surgery: a retrospective analysis

Background

Postoperative desaturation in older individuals is rarely addressed in the literature. The objective of this retrospective study was to investigate whether a preoperative spirometric test and arterial blood gas analysis (ABGA) might predict postoperative desaturation after spinal anesthesia in extreme older patients.

Methods

The medical records of 399 patients (age ≥ 80 yrs) who were administered spinal anesthesia for a femur neck fracture surgery were retrospectively reviewed. Early postoperative desaturation was defined as a reduction of oxygen saturation (SpO₂) below 90% within 3 days of surgery, despite O₂ supply via a nasal prong. Binary logistic regression analysis was used to identify predictors of early postoperative desaturation.

Results

The incidence of postoperative desaturation was 12.5%. Major morbidity rate was significantly higher in the desaturation group (n = 50) than that in the non-desaturation group (n = 349) (14% vs. 3.2%, P = 0.001) with more frequent postoperative stays in the intensive care unit (22% vs. 12%, P = 0.004). In a binary logistic regression analysis, preoperative ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FiO₂ ratio) (OR, 0.972; 95% CI 0.952–0.993; P = 0.010) and history of cardiovascular disease (OR, 2.127; 95% CI 1.004–4.507; P = 0.049) predicted postoperative desaturation.

Conclusions

Preoperative PaO₂/FiO₂ ratio, but not preoperative spirometry, was predictive of the postoperative desaturation in older patients after being administered spinal anesthesia for femur fracture surgery. Based on our results, preoperative ABGA may be helpful in predicting early postoperative desaturation in these patients.

Effects of continuous positive airway pressure in patients at high risk of obstructive sleep apnea during propofol sedation after spinal anesthesia

In patients with obstructive sleep apnea, short-term use of a continuous positive airway pressure mask improves oxygenation, decreases the apnea-hypopnea index, and reduces hemodynamic instability. In this study, we investigated the effects of use of a continuous positive airway pressure mask in patients at high risk of obstructive sleep apnea during propofol sedation after spinal anesthesia. Forty patients who underwent propofol sedation after spinal anesthesia for transurethral bladder or prostate resection with a STOP-Bang score of 3 or more were enrolled in this study. Patients were randomly divided into two groups: a simple oxygen mask group (n = 20) and a continuous positive airway pressure mask group (n = 20). After spinal anesthesia, propofol was injected at a target concentration of 1.3 mcg/ml via a target concentration control injector. ApneaLink™ was applied to all patients. Patients in the simple oxygen mask group were administered oxygen at a rate of 6 L/min through a simple facial mask. Patients in the CPAP mask group were connected to a pressurizer, and oxygen (6 L/min, 5-15 cm H₂O) was administered. Blood pressure, heart rate, respiratory rate, and oxygen saturation were recorded preoperatively, after spinal anesthesia, and every 5 min after the injection of propofol to observe hemodynamic changes. Apnea-hypopnea index was estimated using ApneaLink™. There were no significant differences in hemodynamic changes between the two groups. Apnea-hypopnea index was significantly reduced in the continuous positive airway pressure mask group compared to the simple facial mask group. Application of a continuous positive airway pressure mask in a patient at high risk of obstructive sleep apnea can lower the incidence of obstructive sleep apnea during sedation without a significant effect on hemodynamic stability.

Impaired left ventricular filling is associated with decreased pulse oximetry values

OBJECTIVES

The aim of this study was to investigate the association between echocardiographic measures of diastolic left ventricular dysfunction and decreased arterial oxyhaemoglobin saturation measured with pulse oximetry (SpO₂).

DESIGN

This is a cross-sectional population-based survey of Norwegian adults. Values obtained using echocardiography, pulse oximetry, and spirometry were included. The primary outcome was abnormal mitral Doppler inflow, defined as normal: E/A ratio 0.75-1.5 and EDT ≥ 140 ms; abnormal: E/A ratio <0.75 or >1.5 or EDT <140 ms. The associations between this outcome and possible predictors, including SpO₂ ≤ 95%, were analysed using univariable and multivariable logistic regression.

RESULTS

A total of 1782 participants aged 50 years or older (54% women, mean age 67.5 years) were included in the analysis. Abnormal mitral Doppler inflow was found in 595 participants. After adjusting for age, gender, previous myocardial infarction, smoking history, dyspnoea, obesity, and decreased lung function, SpO₂ ≤ 95% predicted abnormal mitral Doppler flow with an odds ratio (OR) of 1.6 [95% confidence interval (CI) 1.1-2.4]. Hypertension and BMI > =30 were also significant predictors of impaired filling, with OR of 1.7 (95% CI 1.1-2.7) OR and 1.5 (95% CI 1.2-1.9), respectively.

CONCLUSION

Decreased SpO₂ was a significant predictor of abnormal mitral Doppler flow. Diastolic dysfunction should be considered when SpO₂ ≤ 95% is found.

Long-Term Oxygen Therapy in COPD Patients Who Do Not Meet the Actual Recommendations

Chronic respiratory failure due to chronic obstructive pulmonary disease (COPD) is an increasing problem worldwide. Many patients with severe COPD develop hypoxemic respiratory failure during the natural progression of disease. Long-term oxygen therapy (LTOT) is a well-established supportive treatment for COPD and has been shown to improve survival in patients who develop chronic hypoxemic respiratory failure. The degree of hypoxemia is severe when partial pressure of oxygen in arterial blood (PaO₂) is ≤55 mmHg and moderate if PaO₂ is between 56 and 69 mmHg. Although current guidelines consider LTOT only in patients with severe resting hypoxemia, many COPD patients with moderate to severe disease experience moderate hypoxemia at rest or during special circumstances, such as while sleeping or exercising. The efficacy of LTOT in these patients who do not meet the actual recommendations is still a matter of debate, and extensive research is still ongoing to understand the possible benefits of LTOT for survival and/or functional outcomes such as the sensation of dyspnea, exacerbation frequency, hospitalizations, exercise capacity, and quality of life. Despite its frequent use, the administration of "palliative" oxygen does not seem to improve dyspnea except for delivery with high-flow humidified oxygen. This narrative review will focus on current evidence for the effects of LTOT in the presence of moderate hypoxemia at rest, during sleep, or during exercise in COPD.