Oxyhemoglobin Saturation Research Articles

The effect of dietary intake on apneic performance, cardiovascular and splenic responses during repeated breath holds.

Static apneas performed after an overnight fast as opposed to postprandially have been evinced to improve apneic performance. However, no study has explored the effect of dietary intake on apneic performance, cardiovascular or splenic responses over a series of repeated apneas. Ten healthy adults attended the laboratory on three separate occasions (≥48-h apart): after a 14-h fast (F14), 1 h postconsumption of a high-calorie, high-carbohydrate (HCHC) meal, or 1 h postconsumption of a low-calorie, low-carbohydrate (LCLC)-based meal. During each visit, the subjects performed a hyperoxic rebreathing trial and a series of three repeated maximal static apneas. Heart rate, peripheral oxyhemoglobin saturation ([Formula: see text]), and gas exchange were monitored continuously, whereas splenic volume (SV) and hematology were assessed after the rebreathing and apneas. At rest, after HCHC, the respiratory exchange ratio (0.87 ± 0.17, P ≤ 0.043), expired minute volume of carbon dioxide (CO2; HCHC, 0.35 ± 0.09 L/min, P ≤ 0.014), and SV (227 ± 45 mL, P ≤ 0.031) were higher compared with F14 (0.71 ± 0.08; 0.23 ± 0.04 L/min; 204 ± 49 mL) and LCLC (0.72 ± 0.07; 0.25 ± 0.03 L/min; 199 ± 49 mL). A faster CO2 accumulation was recorded during the HCHC (96 ± 35 s) rebreathing trial (F14, 162 ± 42 s, P = 0.001; LCLC, 151 ± 23 s, P = 0.002). Longer apneas were reported in F14 compared with HCHC (apneas 1-3, P ≤ 0.046) and LCLC (apneas 2-3, P ≤ 0.006). After the first apnea, SV was lower in F14 (141 ± 43 mL, P = 0.015) compared with HCHC (180 ± 34 mL). Moreover, after the third apnea, end-tidal partial pressure of oxygen and nadir [Formula: see text] were lower in F14 (8.6 ± 2.2 kPa, P = 0.028; 77 ± 13%, P = 0.009) compared with HCHC (10.1 ± 1.7 kPa; 84 ± 9%). No differences were measured in end-apneic end-tidal partial pressure of CO2, heart rate nor hematology across diets. Fasting improved apneic performance with apneas being terminated at lower oxygen levels through altering the rate of CO2 accumulation but without affecting the cardiovascular responses.

THE ROLE OF HYDROXYUREA IN INCREASING PULSE OXIMETRY AMONG PATIENTS WITH SICKLE CELL DISEASE

To identify the influence of hydroxyurea (HU) on oxygen saturation levels among patients with Sickle Cell Disease (SCD). A cross-sectional study was carried out that evaluated the use of HU for at least 1 year and the oxygen saturation measured on the oximeter in patients recruited in a SCD cohort in Brazil. A total of 275 patients were evaluated and 132 were included in this study. Inclusion criteria were (i) SS genotype, (ii) age over 18 years, (iii) HU use for more than 1 year (iv) no HU use, (v) active follow-up. Patients who did not use HU were the control group. The HU group had 57 patients with a mean age of 32 (±13.38) years, 50.88% women and 49.12% men. The means of Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Heart Rate (HR) and Oxygen Saturation (SpO 2 ) in this group were, respectively, 117.95 (±15.52) mmHg, 65.39 (±11.22) mmHg, 81.40 (±14.55) bpm and 93.02 (±14.55)%. The Control group consisted of 32 patients, the mean age was 30.50 (±10.92) years, 56.25% were women and 43.75% were men. The means of SBP, DBP, HR and SpO 2 in the control were respectively 114.69 (±12.37) mmHg, 62.44 (±9.37) mmHg, 80.19 (±15.66) bpm and 90.16 (±6.16)%. The difference between SpO 2 in the groups was statistically significant (p = 0.01). In the other variables evaluated there was no statistical significance. Oxygen desaturation is common in SCD and predicts clinical severity. Hypoxemia is associated with risk of stroke, abnormal transcranial Doppler velocities, elevation of tricuspid regurgitation, diastolic dysfunction, increased incidence of vaso-occlusive crises and chest syndrome sharp. Pulse oximetry is a non-invasive method of measuring oxyhemoglobin saturation. Peripheral perfusion, external light sources, and skin color and device quality should be observed. HU is the primary therapy in SCD and is capable of increasing the production of fetal hemoglobin (HbF). Studies have shown a strong correlation between peripheral SpO 2 and HbF level, so treatments that elevate HbF should impact desaturation and be beneficial for complications associated with hypoxia. In the United Kingdom, there is already a recommendation from the HU for the treatment of chronic hypoxemia in SCD. The measurement of SpO 2 is crucial for effective management in SCD. The association between HbF and SpO 2 reaffirms the importance of interventions that are able to increase both, like the HU. This study shows that the patients under use of HU had a significantly higher SpO 2 when compared to patients without it.

A NEW WEARABLE BRACE MONITORING MULTIPLE PHYSIOLOGICAL PARAMETERS BASED ON THE NB-IoT TECHNIQUE

Objective: This study is aimed to design wearable care equipment based on the narrow-band Internet of Things (NB-IoT) to assist in applying health-related big data and gain the optimum treatment time for patients with fractures. Methods: A wearable care equipment based on the NB-IoT technique (namely, a brace) was designed by combining sensors with embedded systems, man–machine interaction technique, and so on. Also, the exercise heart rate, the surface temperature of disease location, and the data on oxyhemoglobin saturation of patients were acquired using sensors. Next, these data were sent to an application (APP) on a cell phone after transmission to a single-chip machine for processing. Finally, the data on heart rate, body temperature, blood oxygen, and their variation curves were displayed on the APP. Results: The wearable care equipment could provide a normal average recovery curve for patients with fractures, which was instrumental for patients and doctors to fully grasp the rehabilitation condition. If the key indicators were abnormal and exceeded the threshold value, the wearable equipment generated an early warning signal to alert patients to seek medical attention in time. Conclusions: The test results indicated that the wearable care equipment based on the NB-IoT technique could realize the acquisition, storage, and analysis of the physiological parameters of patients. The wearable equipment had a series of characteristics, including low cost, low power dissipation, stable signal connection, and strong practicability, having a certain practical significance for the consistency of enhancing the health service and assisting the health-related big data development.

Regional Intravenous Anaesthesia (Bier's block) in Black-headed Vulture (Coragyps atratus) Submitted to Digit Amputation

Background: The Coragyps atratus flies long distances in search of food and has a marked behaviour of food competition. Since they are frequently found in areas of recent human occupation, they are subject to trauma, which may require surgical interventions. Locoregional blocks are used as part of a balanced-anaesthesia protocol and are currently being evaluated in birds, with brachial plexus block being the main technique described in the literature. However, to our knowledge, this is the first description of intravenous regional anaesthesia (Bier's block) in a vulture. Thus, we aim to report the use of Bier's block with 1% lidocaine, in a black-headed vulture submitted to digit amputation. Case: A black-headed vulture (Coragyps atratus), weighing 2 kg, was rescued and referred to the Veterinary Hospital due to its inability to fly. Physical examination revealed a swollen digit in the right pelvic limb. Radiographic examination confirmed the intermediate phalanx fracture of the 4th digit of the right pelvic limb with signs suggestive of advanced osteomyelitis. The animal was referred to surgery for amputation of the affected digit. Before surgery, water and food were withdrawn for 12 h. Pre-anaesthetic medication consisted of 1 mg/kg midazolam and 0.5 mg/kg morphine intramuscularly (IM). Anaesthetic induction was performed through face mask with isoflurane, followed by orotracheal intubation with a 3 mm-endotracheal tube. Anaesthesia was maintained with isoflurane through a non-rebreathing circuit in 100% oxygen. Using a multiparametric monitor, heart rate (HR), respiratory rate (RR), end-tidal CO2 (EtCO2), oxyhemoglobin saturation (SpO2), electrocardiography (ECG), systolic blood pressure (SBP) and core temperature (CT) were evaluated. Antisepsis of the right pelvic limb was performed and an elastic band was applied around the distal region of the affected tibia to serve as a tourniquet. A scalp vein set was used to access the lateral saphenous vein in the region distal to the tourniquet, and 5 mg/kg lidocaine 1% was injected intravenously. The patient remained stable during the procedure, with no need for analgesic rescue. The tourniquet was gradually released 40 min past its application, being completely removed after 45 min of surgery. The anaesthetic supply was interrupted, with extubation after 4 min; the patient had satisfactory anaesthetic recovery. Discussion: The present report describes the success in using the technique of intravenous regional anaesthesia with 1% lidocaine for digit amputation performed on a specimen of black-headed vulture. The pre-anaesthetic medication provided analgesia, satisfactory sedation for venoclysis, and anaesthetic induction without complications. Anaesthetic induction and maintenance in birds are preferably performed with inhaled anaesthetics, thus the choice of mask induction. Despite the reduction in RR soon after induction, the patient remained on spontaneous ventilation. Bier's block using 5 mg/kg lidocaine showed to be an easy and safe technique in vultures, but doses up to 6 mg/kg lidocaine are not associated with adverse effects in birds. The intravenous regional anaesthesia technique described in this manuscript promoted adequate analgesia for the digit amputation procedure in black-headed vultures and allowed hemodynamic stability without significant anaesthetic complications. Thus, the present report points to the potential use of this locoregional block in other birds. Keywords: locorregional block, lidocaine, anaesthesia. Título: Anestesia regional intravenosa (bloqueio bier) em urubu-de-cabeça-preta (Coragyps atratus) submetido à amputação de dígito. Descritores: bloqueio locorregional, lidocaína, anestesia.

Cross-adaptation between heat and hypoxia: mechanistic insights into aerobic exercise performance.

Acclima(tiza)tion to heat or hypoxia enhances work capacity in hot and hypoxic environmental conditions, respectively; an acclimation response is considered to be mediated by stimuli-specific molecular/systemic adaptations and potentially facilitated by the addition of exercise sessions. Promising findings at the cellular level provided the impetus for recent studies investigating whether acclimation to one stressor will ultimately facilitate whole body performance when exercise is undertaken in a different environmental condition. The present critical Mini-Review examines the theory of cross-adaptation between heat and hypoxia with particular reference to the determinants of aerobic performance. Indeed, early functional adaptations (improved exercise economy and enhanced oxyhemoglobin saturation) succeeded by later morphological adaptations (increased hemoglobin mass) might aid acclimatized humans perform aerobic work in an alternative environmental setting. Longer-term acclimation protocols that focus on the specific adaptation kinetics (and further allow for the adaptation reversal) will elucidate the exact physiological mechanisms that might mediate gains in aerobic performance or explain the lack thereof.

Mandibular Advancement Device for Severe Obstructive Sleep Apnea: A Case Report Indicating a Way to Personalize Treatment

The mandibular advancement device (MAD) is a therapeutic option for obstructive sleep apnea syndrome (OSAS); however, for severe cases, it has a lower efficacy compared to continuous positive airway pressure (CPAP). This report aimed to present the efficacy of MAD in a patient with severe OSAS who refused CPAP. Video-polysomnography and polygraphy were performed before and after treatment, respectively. Three months after fitting and titrating the MAD, the apnea–hypopnea index was reduced from 56.2 events/h to 1.3 events/h and the minimum oxyhemoglobin saturation increased from 80% to 91%. Snoring time reduced from 75.2% to 0.2%. Our patient presented with low body fat, retrognathia, pharyngeal obstruction mainly along the anteroposterior axis and at the base of the tongue, and the ability to make wide protrusive movements with the jaw. In our opinion, these features could constitute a phenotype that may predict a positive response to MAD treatment even in severe cases of OSAS.

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.

Improved Inflammatory and Cardiometabolic Profile After Soft-Tissue Sleep Surgery for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is associated with a rise in serum inflammatory markers, which may be attenuated by sleep surgery. To evaluate whether sleep surgery was associated with improved levels of proinflammatory markers in adults with OSA. Two authors independently searched Cochrane, Embase, and PubMed databases from inception through June 14, 2022. Two authors searched the Cochrane, Embase, and PubMed databases for studies comparing preoperative and postoperative levels of serum biomarkers in patients undergoing sleep surgery. Data were extracted from included articles into a structured proforma. Meta-analyses of the standardized mean difference (SMD) were conducted in random-effects models. To ensure relevance to clinicians and patients, the probability of benefit and number needed to treat were calculated for outcomes that demonstrated a statistically significant effect after sleep surgery. The primary outcome was the preoperative and postoperative levels of serum biomarkers in patients undergoing sleep surgery, including C-reactive protein (CRP), glucose, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and interleukin-6 (IL-6). Data analysis was performed from April to May 2022. Of the 3218 studies screened, 26 studies with 1187 patients (mean [SD] age, 42.8 [11.1] years; 932 [78.5%] men and 255 [21.5%] women) were included. Soft-tissue sleep surgery was associated with a large decrease in CRP (SMD, -0.377; 95% CI, -0.617 to -0.137), total cholesterol (SMD, -0.267; 95% CI, -0.417 to -0.116), LDL (SMD, -0.201; 95% CI, -0.344 to -0.058), IL-6 (SMD, -1.086; 95% CI, -1.952 to -0.221), tumor necrosis factor-α (SMD, -0.822; 95% CI, -1.617 to -0.027), triglyceride (SMD, -0.186; 95% CI, -0.301 to -0.071), and leptin (SMD, -0.519; 95% CI, -0.954 to -0.083) in patients with OSA. Meta-regression highlighted that increased age, higher preoperative score for cumulative sleep time percentage with oxyhemoglobin saturation less than 90% (CT90), and greater change in CT90 postoperatively were associated with a greater decrease in serum CRP levels after soft-tissue sleep surgery. A greater reduction in apnea hypopnea index (AHI) was strongly associated with a greater reduction in total cholesterol and LDL. A greater reduction in body mass index and AHI were also associated with a greater increase in HDL. The findings of this systematic review and meta-analysis of 26 studies suggest that sleep surgery is associated with decreased levels of CRP, total cholesterol, LDL, triglyceride, IL-6, leptin, and TNF-α, which may improve the inflammatory and cardiometabolic profile of patients who undergo sleep surgery.

A Machine Learning Model for Predicting Hospitalization in Patients with Respiratory Symptoms during the COVID-19 Pandemic.

A machine learning approach is a useful tool for risk-stratifying patients with respiratory symptoms during the COVID-19 pandemic, as it is still evolving. We aimed to verify the predictive capacity of a gradient boosting decision trees (XGboost) algorithm to select the most important predictors including clinical and demographic parameters in patients who sought medical support due to respiratory signs and symptoms (RAPID RISK COVID-19). A total of 7336 patients were enrolled in the study, including 6596 patients that did not require hospitalization and 740 that required hospitalization. We identified that patients with respiratory signs and symptoms, in particular, lower oxyhemoglobin saturation by pulse oximetry (SpO2) and higher respiratory rate, fever, higher heart rate, and lower levels of blood pressure, associated with age, male sex, and the underlying conditions of diabetes mellitus and hypertension, required hospitalization more often. The predictive model yielded a ROC curve with an area under the curve (AUC) of 0.9181 (95% CI, 0.9001 to 0.9361). In conclusion, our model had a high discriminatory value which enabled the identification of a clinical and demographic profile predictive, preventive, and personalized of COVID-19 severity symptoms.

Association Between Smoking Behavior and Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis.

To systematically review the association between smoking behavior and obstructive sleep apnea (OSA). PubMed, Medline, the Cochrane Library, EMBASE, and Scopus databases were used to conduct this review. The two researchers independently screened the literatures, conducted the quality assessment, and data extraction according to the inclusion and exclusion criteria. The RevMan 5.3 was used to analysis the apnea hypopnea index (AHI) index, min saturation of oxyhemoglobin (SaO2), Epworth Sleepiness Scale (ESS) score, and oxygen desaturation index (DOI) and publication bias analysis to assess the effect of smoking on OSA patients. Furthermore, we performed subgroup of the severity of OSA, different countries of sample origin (western countries or eastern countries), and pack-years (PYs < 10 or PYs ≥ 20) to analyze the heterogeneity. Thirteen studies were included in this analysis that conformed to inclusion criteria and exclusion criteria. Totally 3654 smokers and 9796 non-smokers have participated. The meta-analysis of 13 studies demonstrated that AHI levels were significantly higher in smoker group compared with non-smoker, ESS scores were also significantly higher in smoker group compared with non-smoker, min SaO2 levels were obviously lower in smoker group compared with non-smoker, however, DOI levels hadn't significantly different between two groups. The subgroup analysis showed that there was an association between severe OSA, eastern countries, pack-years, and smoking. Smoking behavior is a significant association with OSA. Heavy smokers with histories of more than 20 PYs were at a higher risk of OSA. Moreover, patient with severe OSA exhibited a significantly association with smoking compared with patients with mild or moderate OSA. The relationship between smoking and OSA was controversial, especially, whether smoking increase or aggravate the risk of OSA. In our review and meta-analysis, we demonstrated that smoking behavior is a significant association with OSA. Heavy smokers with histories of more than 20 PYs were at a higher risk of OSA. Moreover, patient with severe OSA exhibited a significant association with smoking compared with patients with mild or moderate OSA. More prospective long-term follow-up studies about effect of quit smoking on OSA are recommended to establish the further relationship.

Isovolemic hemodilution in chronic mountain sickness acutely worsens nocturnal oxygenation and sleep apnea severity.

Chronic mountain sickness (CMS) is commonly observed among Andean and other highland populations. Sleep-disordered breathing (SDB) is highly prevalent at high altitude, and SDB and nocturnal hypoxemia have been observed in CMS. Phlebotomy is commonly performed to treat CMS, but it is unknown whether reducing hematocrit improves SDB. We hypothesized that isovolemic hemodilution (IVHD) in CMS would reduce SBD severity and improve sleep efficiency. Six participants with CMS and 8 without CMS, all residents of Cerro de Pasco, Peru (altitude 4340 m), completed baseline nocturnal sleep studies. CMS participants then underwent IVHD, and nocturnal sleep studies were repeated 24-48 hours after IVHD. We analyzed sleep apnea severity, nocturnal oxygenation, and sleep quality in those with CMS relative to those without CMS, and the effects of IVHD in CMS participants. Participants with CMS did not have altered sleep architecture, sleep apnea severity, or nocturnal oxygenation relative to non-CMS participants. However, IVHD in CMS increased apnea-hypopnea index (40.9 ± 6.9 events/h to 61.5 ± 7.7 events/h, P = .009). IVHD increased oxyhemoglobin desaturation index (P = .008) and the percentage of sleep time spent with oxyhemoglobin saturation at or below 80% (P = .012). There was no effect of IVHD on sleep efficiency, arousal index, or sleep staging. In this cohort, CMS was not associated with worsened SDB or changes in sleep architecture. IVHD, a putative therapeutic option for participants with CMS, appears to worsen nocturnal oxygenation and SDB within 48 hours post-IVHD. Sanchez-Azofra A, Villafuerte FC, DeYoung PN, etal. Isovolemic hemodilution in chronic mountain sickness acutely worsens nocturnal oxygenation and sleep apnea severity. J Clin Sleep Med. 2022;18(10):2423-2432.

Variations among Electronic Health Record and Physiologic Streaming Vital Signs for Use in Predictive Algorithms in Pediatric Severe Sepsis

AbstractObjective This study sought to describe the similarities and differences among physiologic streaming vital signs (PSVSs) and electronic health record (EHR)-documented vital signs (EVSs) in pediatric sepsis.Methods In this retrospective cohort study, we identified sepsis patients admitted to the pediatric intensive care unit. We compared PSVS and EVS measures of heart rate (HR), respiratory rate, oxyhemoglobin saturation, and blood pressure (BP) across domains of completeness, concordance, plausibility, and currency.Results We report 1,095 epochs comprising vital sign data from 541 unique patients. While counts of PSVS measurements per epoch were substantially higher, increased missingness was observed compared with EVS. Concordance was highest among HR and lowest among BP measurements, with bias present in all measures. Percent of time above or below defined plausibility cutoffs significantly differed by measure. All EVS measures demonstrated a mean delay from time recorded at the patient to EHR entry.Conclusion We measured differences between vital sign sources across all data domains. Bias direction differed by measure, possibly related to bedside monitor measurement artifact. Plausibility differences may reflect the more granular nature of PSVS which can be critical in illness detection. Delays in EVS measure currency may impact real-time decision support systems. Technical limitations increased missingness in PSVS measures and reflect the importance of systems monitoring for data continuity. Both PSVS and EVS have advantages and disadvantages that must be weighed when making use of vital signs in decision support systems or as covariates in retrospective analyses.

Central and mixed sleep apnea related to patients treated with maxillomandibular advancement for obstructive sleep apnea: A retrospective cohort study

The aim of this study was to evaluate the clinical efficacy of maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA) patients with a percentage of central and mixed apnea index in the total apnea−hypopnea index (CMAI%) ≧25%.Patients treated with MMA for OSA were retrospectively evaluated for baseline and postoperative patient data and polysomnographic results. The pre- and postoperative obstructive, central and mixed apnea parameters were compared.Of the included 78 patients, 21 patients (27%) presented with CMAI% ≧25% (median CMAI%, 49.1%; 35.9–63.8) prior to MMA. In 67% of these cases, MMA resulted in CMAI% <25 (median CMAI%, 6.1%; 2.1–8.9) and significantly improved the apnea−hypopnea index (AHI) (p < 0.001), the lowest oxyhemoglobin saturation (p < 0.001), central and mixed apnea index (p < 0.001), percentage of central and mixed apneas of total AHI (p = 0.004), central apnea index (p < 0.001), and mixed apnea index (p < 0.001). CMAI% ≧25% emerged in 25% of patients after MMA (median CMAI%, 49.1%; 35.9–63.8).Within the undeniable limitations of the study, it seems that the presence of CMAI% ≧25% should not be regarded as a contraindication for MMA in OSA patients.

0715 Diagnosis of Sleep Disordered Breathing in Patients with Interstitial Lung Disease: A Retrospective Evaluation of Polysomnogram and Home Sleep Apnea Testing Using Peripheral Arterial Tonometry

Abstract Introduction Previous studies have shown that sleep disordered breathing (SDB) is common in patients with Interstitial Lung Disease (ILD), and oximetry is often used for screening prior to further diagnostic testing. Current guidelines recommend polysomnography (PSG) for diagnosis of SDB in patients with significant pulmonary disease, however, home sleep apnea tests (HSAT) are increasingly used in clinical practice for a variety of reasons despite lack of evidence regarding accuracy in this population. In this study, we evaluate the correlation between screening oximetry, a commercial brand HSAT (WatchPAT®) and PSG to examine the diagnostic accuracy of this HSAT technology in patients with ILD. Methods The institution electronic medical record was screened for patients with a diagnosis code for ILD who underwent screening oximetry followed by PSG or HSAT using peripheral arterial tonometry from July 1, 2012 to present. Clinical review confirmed presence of ILD according to American Thoracic Society guidelines. Among the respective cohorts, Paired Wilcoxon Test was used to compare the oximetry 4% oxygen desaturation index (ODI) to the HSAT ODI and PSG apnea-hypopnea index (AHI) as well as percent time spent below oxyhemoglobin saturation of 89%. Spearman correlation was used to correlate the oximetry ODI and parameters of SDB on HSAT and PSG. Results Data was analyzed for 25 patients who had undergone oximetry/HSAT and for 25 patients who had undergone oximetry/PSG. Oximetry ODI showed no significant difference from PSG AHI (p = 0.2635) or between HSAT ODI (p = 0.0755), and no difference was seen in hypoxic time between oximetry and PSG (p = 0.9789). Hypoxic time on HSAT was significantly longer than that on oximetry (p &amp;lt; 0.001). Using HSAT ODI as the standard, HSAT AHI and respiratory disturbance index (RDI) showed rs of 0.9638 and 0.8913 respectively, while oximetry ODI was 0.3893. Compared to PSG AHI, the PSG RDI and oximetry ODI rs were 0.9759 and 0.7407 respectively. Conclusion Among patients with ILD, screening oximetry appears to correlate more strongly with indices of SDB and hypoxic time on PSG rather than HSAT. Further studies are warranted to evaluate efficacy of additional HSAT testing modalities in this patient population. Support (If Any)

Nocturnal hypoxemia and central apneas increase mortality, but not recurrent ischemic events after ischemic stroke

BackgroundThe aim of the study was to investigate whether findings in cardiorespiratory polygraphy had an association with stroke mortality or ischemic event recurrence after ischemic stroke. MethodsWe prospectively studied 204 ischemic stroke patients who underwent cardiorespiratory polygraphy within the first 48 h after the symptom onset. We followed all these patients for a median of 6.2 years. We evaluated mortality, time of survival, causes of death and new ischemic events. ResultsOf 204 ischemic stroke patients, 43 died and 48 had a new ischemic event during the follow-up. The lowest arterial oxyhemoglobin saturation (min SaO₂) (P = 0.007) was lower, the percentage of time spent below arterial oxyhemoglobin saturation less than 90% (T90) (P = 0.005) was higher, and central apnea index per hour (CAI/h) (P = 0.04) was higher among the deceased. Male gender, older age, diabetes mellitus, elevated modified Rankin scale (mRS) score, lower Glasgow Coma Scale (GCS) score and CAI/h independently predicted higher mortality. Peripheral arterial disease (PAD) and higher National Institutes of Health Stroke Scale (NIHSS) score were independent predictors for a recurrent ischemic event. Among those having respiratory event index (REI) at least 30, older age and lower GCS score independently predicted higher mortality. Only 21 stroke patients initiated continuous positive airway pressure (CPAP) treatment; of those, only one had a new ischemic event. ConclusionsThe non-survivors had more severe nocturnal hypoxemia and more central apneas than survivors. Among patients with REI at least 30/h, increased CAI predicted higher mortality, but not independently. Clinical trial registrationURL:http://www.clinicaltrials.gov. Unique identifier: NCT01861275

Oxygen Therapy during Exercise in Patients with Interstitial Lung Diseases.

Introduction: ILDs are a varied group of diffuse parenchymal lung diseases associated with high morbidity and mortality. Current treatments can only slow their progression but not cure the disease. Other treatments such as oxygen therapy can also be used as support. We know very little about the effects of oxygen therapy on patients with ILDs. The aim of this study was to collect data from the literature in order to determine whether oxygen therapy can actually decrease the mortality rate or whether it is only suitable for supportive therapy for patients with ILDs. Methods: We reviewed the literature since 2010 on oxygen therapy during exercise in patients with ILDs. Studies that used cardio-pulmonary tests were excluded. We only reviewed those that used the 6 min walking test (6MWT) or the free walking test. We located 11 relevant articles. Results: All the articles except a Japanese study showed an augmentation in oxyhaemoglobin saturation during exercise when oxygen was supplied. A 2018 study called AmbOx provided important data on the effects of oxygen therapy during daily activities, showing significant improvements in quality of life. Conclusions: This review showed that the literature on the benefits of oxygen therapy in patients with ILDs does not provide sufficient evidence to draft specific guidelines. It was not possible to conclude whether oxygen therapy has an effect on mortality or can only play a supportive role.

Respiratory Arousals in Patients with Very Severe Obstructive Sleep Apnea and How They Change after a Non-Framework Surgery.

Respiratory arousal is the change from a state of sleep to a state of wakefulness following an apnea or hypopnea. In patients with obstructive sleep apnea (OSA), it could have a helpful role to activate upper airway muscles and the resumption of airflow and an opposing role to contribute to greater ventilatory instability, continue cycling, and likely exacerbate OSA. Patients with very severe OSA (apnea-hypopnea index (AHI) ≥ 60 events/h) may have specific chemical (e.g., possible awake hypercapnic hypoxemia) and mechanical (e.g., restricted dilator muscles) stimuli to initiate a respiratory arousal. Little was reported about how respiratory arousal presents in this distinct subgroup, how it relates to AHI, Epworth Sleepiness Scale (ESS), body mass index (BMI), and oxygen saturation, and how a non-framework surgery may change it. Here, in 27 patients with very severe OSA, we show respiratory arousal index was correlated with each of AHI, mean oxyhemoglobin saturation of pulse oximetry (SpO2), mean desaturation, and desaturation index, but not in BMI or ESS. The mean (53.5 events/h) was higher than other reports with less severe OSAs in the literature. The respiratory arousal index can be reduced by about half (45.3%) after a non-framework multilevel surgery in these patients.

The effect of brain serotonin deficiency on breathing is magnified by age.

Serotonin is an important mediator modulating behavior, metabolism, sleep, control of breathing, and upper airway function, but the role of aging in serotonin‐mediated effects has not been previously defined. Our study aimed to examine the effect of brain serotonin deficiency on breathing during sleep and metabolism in younger and older mice. We measured breathing during sleep, hypercapnic ventilatory response (HCVR), CO2 production (VCO2), and O2 consumption (VO2) in 16–18‐week old and 40–44‐week old mice with deficiency of tryptophan hydroxylase 2 (Tph2), which regulates serotonin synthesis specifically in neurons, compared to Tph2 +/+ mice. As expected, aging decreased VCO2 and VO2. Tph2 knockout resulted in an increase in both metabolic indexes and no interaction between age and the genotype was observed. During wakefulness, neither age nor genotype had an effect on minute ventilation. The genotype did not affect hypercapnic sensitivity in younger mice. During sleep, Tph2 −/− mice showed significant decreases in maximal inspiratory flow in NREM sleep, respiratory rate, and oxyhemoglobin saturation in REM sleep, compared to wildtype, regardless of age. Neither serotonin deficiency nor aging affected the frequency of flow limited breaths (a marker of upper airway closure) or apneas. Serotonin deficiency increased the amount and efficiency of sleep only in older animals. In conclusion, younger Tph2 −/− mice were able to defend their ventilation and phenotypically did not differ from wildtype during wakefulness. In contrast, both young and old Tph2 −/− mice showed sleep‐related hypoventilation, which was manifested by hypoxemia during REM sleep.

A gamified assessment does not identify alterations in cross‐domain cognitive performance with acute moderate hypoxia

INTRODUCTIONThe acute effect of hypoxia on cognition is dependent on the magnitude and duration of the hypoxia, and the assessed cognitive domain. For example, there is little effect of ~1 h exposure to a fraction of inspired oxygen (FiO2) of ~14% on simple cognitive tasks that measure reaction time. However, complex or novel cognitive tasks can be hindered under the same conditions. These possible cognitive alterations are recognized by the use of supplemental oxygen when flying in unpressurized aircraft for &gt;1 h at altitudes &gt;3048 m. Notably, people often cannot recognize their own hypoxia‐induced symptoms. Thus, there is a need to develop objective assessment tools to consistently identify potential detrimental cognitive effects of moderate hypoxia. One potential solution is the use of gamified cognitive assessments, whereby electronic games can provide metrics of changes in cognitive functioning. However, the effect of moderate hypoxia on gamified cognitive performance has never been explored.PURPOSETest the hypothesis that moderate normobaric hypoxia decreases gamified cross‐domain cognitive performance.METHODSFollowing three consecutive days of practice, twenty‐one healthy adults (27 ± 5 y, 9 females) completed five 1 min rounds of the tablet‐based game Gridshot (Statespace Labs, Inc.) at Baseline and 60 and 90 min after exposure to a chamber with an FiO2 = 14.0 ± 0.2% (hypoxia) and FiO2 = 20.6 ± 0.3% (normoxia). Both conditions were completed on the same day and were administered in a single‐blind, block randomized manner. Gridshot is a novel first‐person shooter style assessment in which a participant’s performance is measured as hits (#), misses (#), hit rate (%), hits per second (#/s), shots per second (#/s), median time to hit (s), and shot precision (i.e., the variability of shot locations relative to the center of targets). Arterial oxyhemoglobin saturation was estimated via forehead pulse oximetry (SpO2). Data were analyzed using ANCOVA with a covariate of Baseline and are presented as adjusted means (95% confidence intervals).RESULTSCompared to normoxia (98 ± 1%), SpO2 was lower (p &lt; 0.001) at 60 (91 ± 3%) and 90 (90 ± 3%) min of hypoxia. A main effect of time was identified for average hits (p = 0.039) and hits per second (p = 0.039), such that, independent of condition, average hits [114 (112, 116) vs. 116 (114, 118)] and hits per second [1.89 (1.86, 1.94) vs. 1.93 (1.89, 1.97)] increased from 60 to 90 min. However, no effect of condition or a condition x time interaction was identified for either average hits (p ≥ 0.255) or hits per second (p ≥ 0.255). There were no condition, time, or condition x time interaction effects identified for average misses (p ≥ 0.138), hit rate (p ≥ 0.057), shots per second (p ≥ 0.247), median time to hit (p ≥ 0.220), and shot precision (p ≥ 0.145).CONCLUSIONThese preliminary findings indicate that, compared to normoxia, 90 min of moderate hypoxia does not elicit measurable alterations in metrics of a first‐person shooter stylistic cross‐domain cognitive assessment. More research is required to better understand the ability of gamified cognitive assessments to detect cognitive alterations caused by environmental stressors.

Moderate hypoxia decreases selective attention performance as assessed via a domain‐specific gamified assessment

INTRODUCTIONThe effect of acute hypoxia on cognition is a function of the magnitude and duration of hypoxia and the assessed cognitive domain. For example, there is little effect of acute exposure to a fraction of inspired oxygen (FiO2) of 11‐14% on simple cognitive tasks. However, performance on more complex tasks, such as those involving aspects of executive function, can be hindered under the same conditions. These possible cognitive changes underlie the use of supplemental oxygen when flying in unpressurized aircraft for &gt;1 h at altitudes &gt;3048 m. People often cannot recognize their own symptoms of hypoxia. Thus, there is a need for tools that can identify detrimental cognitive effects of hypoxia. One potential solution is gamified cognitive assessments, where electronic games can provide targeted metrics of cognitive function, such as working memory and selective attention. However, whether gamified assessments of executive function are sensitive to moderate hypoxia is unknown.PURPOSETest the hypothesis that moderate normobaric hypoxia decreases gamified working memory and selective attention performance.METHODSFollowing three consecutive days of practice, twenty‐one healthy adults (27 ± 5 y, 9 females) completed five 1 min rounds of the tablet‐based games Capacity and Multitracker (Statespace Labs, Inc.) at Baseline and 60 and 90 min after exposure to a chamber with an FiO2 = 14.0 ± 0.2% (hypoxia) and FiO2 = 20.6 ± 0.3% (normoxia). Both conditions were completed on the same day and were administered in a single‐blind, block randomized manner. Capacity (a visuospatial working memory game) and Multitracker (a multiple object tracking and selective attention game) in which participant performance is measured as median time to hit (s), correct trials (#), incorrect trials (#), proportion of correct trials (%), and mean difficulty (#). Arterial oxyhemoglobin saturation was estimated via forehead pulse oximetry (SpO2). Data were analyzed using ANCOVA with a covariate of Baseline and are presented as adjusted means (95% confidence intervals).RESULTSCompared to normoxia (98 ± 1%), SpO2was lower (p &lt; 0.001) at 60 (91 ± 3%) and 90 (90 ± 3%) min of hypoxia. For Capacity, there were no condition, time, or interaction effects for the median time to hit (p ≥ 0.268), correct trials (p ≥ 0.310), incorrect trials (p ≥ 0.258), proportion of correction trials (p ≥ 0.272), and mean difficulty (p ≥ 0.761). For Multitracker, a main effect of condition was identified for mean difficulty (p = 0.008), such that, independent of time, the mean difficulty achieved was higher in normoxia [249 (235, 264) vs. 244 (233, 254)]. A main effect of time was identified for correct trials, such that, independent of condition, the number of correct trials increased from 60 [28.5 (27.6, 29.3)] to 90 [28.7 (28.0, 29.4)] min. There were no condition, time, or interaction effects for the median time to hit (p ≥ 0.584), incorrect trials (p ≥ 0.248), and proportion of correction trials (p ≥ 0.162).CONCLUSIONThese preliminary findings indicate that, compared to normoxia, acute moderate hypoxia reduces selective attention, but not working memory, performance determined via domain‐specific cognitive games.