Effect Of Supplemental Oxygen Research Articles

Effect of Supplemental Oxygen on Apgar Score of Newborns in Pregnant Women Undergone Cesarean Section with Spinal Anesthesia

Background: In obstetrics, there have been discussions and changes in procedures surrounding the provision of extra oxygen during cesarean sections performed under spinal anesthesia. Despite its recognized benefits in maintaining maternal cerebral oxygenation, concerns persist about its impact on neonatal health, especially regarding newborn oxygen saturation levels. This gap in understanding the direct effects on immediate neonatal outcomes, particularly Apgar scores, underscores the need for further research. This study aimed to determine the effectiveness of supplement on Apgar scores at one and five minutes post-delivery in newborns of mothers undergoing cesarean sections with spinal anesthesia. Methodology: Through randomized sampling, 100 patients from two hospitals in Iraq were included in this interventional trial. Following approval for research and establishment of inclusion and exclusion criteria, the researcher gathered patient sociodemographic information and average score. The sample is divided into two groups: (50) participants as a study group and (50) participants considered as a control group. With a significance threshold 0.05, the gathered data were examined using descriptive and inferential statistics in Statistical Package for the Social Sciences software version 22. Results: The results demonstrated that the most represented age group in both study and control groups was 25-30 years, and the least represented was 35-40 years. The highest BMI category was 'overweight' in both groups, while 'obese' was the least common. Regarding birth weights, the study group had a higher percentage of normal birth weights than the control group. In APGAR scores after 5 minutes, a significantly higher percentage of newborns in the study group had reassuring scores (7 to 10) compared to the control group. Furthermore, a relevant difference in outcomes was shown by a significant link between the study group and the impact of O2 supplement on APGAR score at (p-value. 0). Sociodemographic factors such as age, education level, occupation, BMI, and gestational age showed no significant correlation with APGAR scores, underscoring the complexity of these factors' influence on neonatal outcomes. Conclusion: The study found that supplemental oxygen positively affects newborns' APGAR scores during Cesarean sections with spinal anesthesia, with the study group showing better scores than the control group. It suggests that improving prenatal care, training in neonatal care, ensuring medical equipment availability, and enhancing obstetric research and education are vital for better neonatal and maternal care in Iraq, ultimately leading to improved health outcomes for mothers and newborns.

Effect of Supplemental Oxygen on von Willebrand Factor Activity and Ristocetin Cofactor Activity in Patients at Risk for Cardiovascular Complications Undergoing Moderate-to High-Risk Major Noncardiac Surgery-A Secondary Analysis of a Randomized Trial.

Increased von Willebrand Factor (vWF) activity mediates platelet adhesion and might be a contributor to the development of thrombotic complications after surgery. Although in vitro studies have shown that hyperoxia induces endovascular damage, the effect of perioperative supplemental oxygen as a possible trigger for increased vWF activity has not been investigated yet. We tested our primary hypothesis that the perioperative administration of 80% oxygen concentration increases postoperative vWF activity as compared to 30% oxygen concentration in patients at risk of cardiovascular complications undergoing major noncardiac surgery. A total of 260 patients were randomly assigned to receive 80% versus 30% oxygen throughout surgery and for two hours postoperatively. We assessed vWF activity and Ristocetin cofactor activity in all patients shortly before the induction of anesthesia, within two hours after surgery and on the first and third postoperative day. Patient characteristics were similar in both groups. We found no significant difference in vWF activity in the overall perioperative time course between both randomization groups. We observed significantly increased vWF activity in the overall study population throughout the postoperative time course. Perioperative supplemental oxygen showed no significant effect on postoperative vWF and Ristocetin cofactor activity in cardiac risk patients undergoing major noncardiac surgery. In conclusion, we found no significant influence of supplemental oxygen in patients undergoing major non-cardiac surgery on postoperative vWF activity and Ristocetin cofactor activity.

Supplemental Oxygen Treats Periodic Breathing without Effects on Sleep in Late-Preterm Infants

Background: The effect of supplemental oxygen on sleep has not been studied in preterm infants. Methods: We studied 18 stable late-preterm infants with observed periodic breathing at a median gestational age of 36 weeks. Polysomnography was performed on room air and on 25% oxygen-enriched ambient air. Results: Supplemental oxygen did not affect sleep stage distribution, sleep efficiency, the frequency of sleep stage transitions, the appearance of rapid-eye movement (REM) sleep periods, or the high number of spontaneous arousals. The percentage in periodic breathing out of total sleep time decreased from 10% (interquartile range [IQR] 5–9%) on room air to 1% (IQR 0–3%) (p < 0.001) on supplemental oxygen. Also, the number of central apneas decreased from 48 (IQR 32–68) to 23 (IRQ 15–32) per hour (p < 0.001), and the number of oxygen desaturations of a minimum 3% from 38 (IQR 29–74) to 10 (IQR 5–24) per hour (p < 0.001). On room air in non-REM sleep, the median end-tidal carbon dioxide values were systematically lower during periodic breathing at 5.1 (IQR 4.6–6.4) kPa than during stable breathing at 5.5 (4.9–5.9) kPa (p < 0.0001). Conclusions: In late-preterm infants, supplemental oxygen effectively reduces periodic breathing and the number of oxygen desaturations while having no significant effect on sleep. The results support the importance of carotid body over-reactivity on the genesis of periodic breathing in preterm infants.

Exercise Tolerance in Patients With Idiopathic Pulmonary Fibrosis, Effect of Supplemental Oxy-Gen.

Exercise tolerance in patients with idiopathic pulmonary fibrosis IPF is mainly limited by mechanical constrain of ventilation and high physiologic dead space. Oxygen enriched gas inhalation seems to increase ventilatory efficiency by reduction of dead space to tidal volume ratio (VD/VT) which probably mirrors improved pulmonary capillary flow and leads to longer physical tolerance at lower level of minute ventilation. The effect is noticeable at FIO2 that can be delivered in rehabilitation purposes or daily living activities.

Effects of Supplemental Oxygen on Cardiovascular and Respiratory Interactions by Extended Partial Directed Coherence in Idiopathic Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic and restrictive disease characterized by fibrosis and inflammatory changes in lung tissue producing a reduction in diffusion capacity and leading to exertional chronic arterial hypoxemia and dyspnea. Furthermore, clinically, supplemental oxygen (SupplO2) has been prescribed to IPF patients to improve symptoms. However, the evidence about the benefits or disadvantages of oxygen supplementation is not conclusive. In addition, the impact of SupplO2 on the autonomic nervous system (ANS) regulation in respiratory diseases needs to be evaluated. In this study the interactions between cardiovascular and respiratory systems in IPF patients, during ambient air (AA) and SupplO2 breathing, are compared to those from a matched healthy group. Interactions were estimated by time series of successive beat-to-beat intervals (BBI), respiratory amplitude (RESP) at BBI onset, arterial systolic (SYS) and diastolic (DIA) blood pressures. The paper explores the Granger causality (GC) between systems in the frequency domain by the extended partial directed coherence (ePDC), considering instantaneous effects. Also, traditional linear and nonlinear markers as power in low (LF) and high frequency (HF) bands, symbolic dynamic indices as well as arterial baroreflex, were calculated. The results showed that for IPF during AA phase: 1) mean BBI and power of BBI-HF band, as well as mean respiratory frequency were significantly lower (p < 0.05) and higher (p < 0.001), respectively, indicating a strong sympathetic influence, and 2) the RESP SYS interaction was characterized by Mayer waves and diminished RESP BBI, i.e., decreased respiratory sinus arrhythmia. In contrast, during short-term SupplO2 phase: 1) oxygen might produce a negative influence on the systolic blood pressure variability, 2) the arterial baroreflex reduced significantly (p < 0.01) and 3) reduction of RSA reflected by RESP BBI with simultaneous increase of Traube-Hering waves in RESP SYS (p < 0.001), reflected increased sympathetic modulation to the vessels. The results gathered in this study may be helpful in the management of the administration of SupplO2.

The effect of supplemental oxygen on 6-minute walk test in chronic obstructive pulmonary disease patients

Introduction: Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disease that associated with abnormal airflow during respiration. It has been demonstrated that supplemental oxygen used in the time of exercise testing has a considerable positive effect in cases with COPD. Objectives: Present study was aimed to investigate the possible effects of supplemental oxygen on the outcomes of 6-minute walk test (6MWT). Patients and Methods: COPD cases were randomly divided into two groups (n= 50/each). Group1; patients who received nasal oxygen during the 6MWT, and group two were patients who did not receive supplemental oxygen during the test. Results: The Shapiro-Wilk test showed that the distribution of all parameters in two groups followed the normal distribution. The total distance walked was 431.54±40.76 m in the intervention group and 399.08±49.94 m in the control group, with a significant difference between the two groups (P= 0.001). After 6MWT, the mean of SpO2 in the intervention group was significantly higher than the control group (P= 0.002) and the degree of dyspnea was significantly lower than the control group (P= 0.031). Conclusion: Overall, supplemental oxygen has significant positive effects in COPD patients, but definitive commentary is needed for further studies. Trial registration: The trial protocol was approved by the Thai Clinical Trials Registry (identifier: TCTR20220122001; https://www.thaiclinicaltrials.org, ethical code; IR.MUI.MED.REC. 1396.308.3).

Exploring Hyperoxia Effects in Cancer—From Perioperative Clinical Data to Potential Molecular Mechanisms

Increased inspiratory oxygen concentration is constantly used during the perioperative period of cancer patients to prevent the potential development of hypoxemia and to provide an adequate oxygen transport to the organs, tissues and cells. Although the primary tumours are surgically removed, the effects of perioperative hyperoxia exposure on distal micro-metastases and on circulating cancer cells can potentially play a role in cancer progression or recurrence. In clinical trials, hyperoxia seems to increase the rate of postoperative complications and, by delaying postoperative recovery, it can alter the return to intended oncological treatment. The effects of supplemental oxygen on the long-term mortality of surgical cancer patients offer, at this point, conflicting results. In experimental studies, hyperoxia effects on cancer biology were explored following multiple pathways. In cancer cell cultures and animal models, hyperoxia increases the production of reactive oxygen species (ROS) and increases the oxidative stress. These can be followed by the induction of the expression of Brain-derived neurotrophic factor (BDNF) and other molecules involved in angiogenesis and by the promotion of various degrees of epithelial mesenchymal transition (EMT).

Is oxygen therapy beneficial for normoxemic patients with acute heart failure? A propensity score matched study

BackgroundThe clinical efficiency of routine oxygen therapy is uncertain in patients with acute heart failure (AHF) who do not have hypoxemia. The aim of this study was to investigate the association between oxygen therapy and clinical outcomes in normoxemic patients hospitalized with AHF using real-world data.MethodsNormoxemic patients diagnosed with AHF on ICU admission from the electronic ICU (eICU) Collaborative Research Database were included in the current study, in which the study population was divided into the oxygen therapy group and the ambient-air group. Propensity score matching (PSM) was applied to create a balanced covariate distribution between patients receiving supplemental oxygen and those exposed to ambient air. Linear regression and logistic regression models were performed to assess the associations between oxygen therapy and length of stay (LOS), and all-cause in-hospital as well as ICU mortality rates, respectively. A series of sensitivity and subgroup analyses were conducted to further validate the robustness of our findings.ResultsA total of 2922 normoxemic patients with AHF were finally included in the analysis. Overall, 42.1% (1230/2922) patients were exposed to oxygen therapy, and 57.9% (1692/2922) patients did not receive oxygen therapy (defined as the ambient-air group). After PSM analysis, 1122 pairs of patients were matched: each patient receiving oxygen therapy was matched with a patient without receiving supplemental oxygen. The multivariable logistic model showed that there was no significant interaction between the ambient air and oxygen group for all-cause in-hospital mortality [odds ratio (OR) 1.30; 95% confidence interval (CI) 0.92–1.82; P = 0.138] or ICU mortality (OR 1.39; 95% CI 0.83–2.32; P = 0.206) in the post-PSM cohorts. In addition, linear regression analysis revealed that oxygen therapy was associated with prolonged ICU LOS (OR 1.11; 95% CI 1.06–1.15; P < 0.001) and hospital LOS (OR 1.06; 95% CI 1.01–1.10; P = 0.009) after PSM. Furthermore, the absence of an effect of supplemental oxygen on mortality was consistent in all subgroups.ConclusionRoutine use of supplemental oxygen in AHF patients without hypoxemia was not found to reduce all-cause in-hospital mortality or ICU mortality.

Effects of oxygen supplementation in autonomic nervous system function during exercise in patients with idiopathic pulmonary fibrosis and exertional desaturation.

Patients with idiopathic pulmonary fibrosis (IPF) have reduced exercise capacity and often present exertional dyspnea and desaturation. The role of autonomic nervous system (ANS) as a pathogenetic contributor to this dysfunction has not been evaluated. To evaluate whether improvement of arterial oxygen saturation (SpO2 ) via oxygen supplementation results to ANS function improvement, during steady state submaximal exercise. This is a secondary analysis of a single-blind, randomized, placebo-controlled, cross-over trial, including 12 IPF patients, with isolated exertional desaturation. Following a maximal cardiopulmonary test, participants underwent two submaximal steady state tests during which they received either supplementary oxygen or medical air. Continuous beat-to-beat blood pressure measurements were recorded (Finapres Medical Systems, Amsterdam, The Netherlands). Autonomic function was assessed non-invasively by heart rate variability (HRV); root mean square of successive differences (RMSSD) and standard-deviation-Poincare-plot (SD1) were used as indices of parasympathetic output. Entropy and detrended fluctuation analysis (DFA) were also used. During rest, oxygen supplementation did not significantly alter RMSSD and SD1. During exercise, subjects presented no significant alterations compared with baseline, in most HRV indices examined. There was no improvement of this behavior with O2 -supplementation. Approximate-entropy increased during exercise, with no differences between protocols. IPF patients presented an inadequate adaptive response of their ANS to exercise and recovery. Although oxygen supplementation significantly prolonged exercise duration and prevented the substantial exertional desaturation, the blunted vagal response to steady-state exercise in these patients was not improved, suggesting that acute oxygen supplementation does not sufficiently improve ANS dysfunction in these patients.

Effects of Supplemental Oxygen During Mechanical Ventilation on Diaphragmatic Blood Flow

Introduction During mechanical ventilation (MV), supplemental oxygen is commonly administered to critically-ill patients to prevent hypoxemia. However, in ICU patients, hyperoxia during MV is associated with increased mortality and a decrease in ventilator free days. Hyperoxic MV can elicit a paradoxical reduction in O2 delivery to the heart, brain, and kidneys. Whereas MV in normoxia diminishes diaphragm perfusion and O2 delivery, the effect of MV with supplemental oxygen on diaphragm perfusion is unknown. Previous studies demonstrate that MV with hyperoxia substantially impairs diaphragm contractile function. Therefore, hyperoxia during MV may potentiate reductions in diaphragm perfusion with MV and predispose patients to problematic weaning. Purpose Using an established animal model of MV, we tested the following hypotheses: 1) MV supplemented with hyperoxic gas (FIO2 0.99) would reduce diaphragmatic blood flow compared to spontaneously breathing (SB) animals, and 2) hyperoxic MV would decrease diaphragmatic blood flow to a greater extent compared to MV with room air (normoxia, FIO2 0.21). Methods Using fluorescent microspheres, tissue blood flow was measured in adult female Sprague-Dawley rats (n = 4) during spontaneous breathing (SB), mechanical ventilation + hyperoxia (MV +O2), and mechanical ventilation + room air (MV + RA). Following microsphere infusion during SB, animals were intubated and immediately ventilated with supplemental hyperoxic gas for 30 min and an arterial blood sample (~100 ul) was collected to confirm hyperoxemia prior to the second microsphere infusion. Thereafter, animals were subjected to MV using room air for 30 min followed by a third infusion of microspheres. Following the final microsphere infusion, tissues were harvested for blood flow analysis. The diaphragm was sectioned into costal (ventral, medial, dorsal) and crural portions to determine blood flow distribution within the diaphragm. Results During MV + O2, average arterial PO2 (PaO2) was 370 ± 39 mmHg. Compared to SB, total diaphragm blood flow was significantly decreased with MV + O2 (50 ± 2 vs 17 ± 3 ml/min/100g; P<0.05) and MV + RA (30 ± 1 ml/min/100g; P<0.05 vs SB). Compared to SB, blood flow to the medial costal diaphragm was reduced during both MV + O2 (59 ± 5 vs 18 ± 4 ml/min/100g; P<0.05) and MV + RA (59 ± 5 vs 29 ± 6 ml/min/100g; P<0.05). During MV + RA, compared to MV + O2, blood flow to the whole diaphragm was higher (30 ± 1 vs 17 ± 3 ml/min/100g; P<0.05). Although not significant, medial costal diaphragm flow tended to be higher with MV + RA versus MV + O2 (P=0.09). Conclusion These data demonstrate that supplementing short term MV with hyperoxia versus room air reduces total diaphragmatic blood flow to a significantly greater degree, suggesting that hyperoxia during MV reduces diaphragmatic O2 delivery. This raises the likelihood that prolonged bouts of MV (i.e. 6+ h) with hyperoxia may accelerate MV-induced vascular dysfunction in the quiescent diaphragm thus exacerbating downstream contractile dysfunction.

The effectiveness of supplemental oxygen during exercise training in patients with chronic obstructive pulmonary disease who show severe exercise-induced desaturation: a protocol for a meta-regression analysis and systematic review

BackgroundSupplemental oxygen during exercise training is used to increase the training effect of an exercise program in patients with chronic obstructive pulmonary disease (COPD) who show exercise-induced desaturation. Exercise-induced desaturation is not clearly defined in the guidelines; however, it is generally defined in clinical studies as a decrease in SpO2 of more than 4% from rest or a decrease to less than 88% during exercise. Although some meta-analyses examined the effectiveness of supplemental oxygen during exercise training, these studies concluded that it does not further improve exercise tolerance compared to exercise training alone. However, supplemental oxygen during exercise training may be effective in improving exercise tolerance in COPD patients with severe exercise-induced desaturation. Therefore, this study will be performed to elucidate the effectiveness of supplemental oxygen during exercise training and the relationship between its effectiveness and severity of exercise-induced desaturation at baseline.MethodsWe will first assess the effectiveness of supplemental oxygen during exercise training in COPD. The main outcome is the change in exercise tolerance before and after the intervention, indicated by the 6-min walking distance, the walking distance, or the walking time in incremental shuttle walking test, and analyzed as the standardized mean difference (SMD). The quality and risk of bias in individual studies will be assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system and risk-of-bias tool (RoB ver.2). If statistical heterogeneity in terms of the effectiveness of exercise tolerance is shown, we will conduct meta-regression analyses to examine the association between the effectiveness of exercise training with supplemental oxygen and severity of exercise-induced desaturation at baseline.DiscussionOne strength of this study is that it is a systematic review with meta-regression analysis to elucidate the effectiveness of supplemental oxygen during exercise training in patients with COPD who show severe exercise-induced desaturation. Furthermore, we will assess the severity of exercise-induced desaturation for which exercise training with supplemental oxygen is effective, the influence of acute effects at baseline, and the effect of supplemental oxygen on adverse events.Systematic review registrationRegistration number, UMIN000039960.

Single-leg exercise training augments in vivo skeletal muscle oxidative flux and vascular content and function in adults with type 2 diabetes.

People with type 2 diabetes (T2D) have impaired skeletal muscle oxidative flux due to limited oxygen delivery. In the current study, this impairment in oxidative flux in people with T2D was abrogated with a single-leg exercise training protocol. Additionally, single-leg exercise training increased skeletal muscle CD31 content, calf blood flow and state 4 mitochondrial respiration in all participants. Cardiorespiratory fitness is impaired in type 2 diabetes (T2D), conferring significant cardiovascular risk in this population; interventions are needed. Previously, we reported that a T2D-associated decrement in skeletal muscle oxidative flux is ameliorated with acute use of supplemental oxygen, suggesting that skeletal muscle oxygenation is rate-limiting to in vivo mitochondrial oxidative flux during exercise in T2D. We hypothesized that single-leg exercise training (SLET) would improve the T2D-specific impairment in in vivo mitochondrial oxidative flux during exercise. Adults with (n=19) and without T2D (n=22) with similar body mass indexes and levels of physical activity participated in two weeks of SLET. Following SLET, in vivo oxidative flux measured by 31 P-MRS increased in participants with T2D, but not people without T2D, measured by the increase in initial phosphocreatine synthesis (P=0.0455 for the group × exercise interaction) and maximum rate of oxidative ATP synthesis (P=0.0286 for the interaction). Additionally, oxidative phosphorylation increased in all participants with SLET (P=0.0209). After SLET, there was no effect of supplemental oxygen on any of the in vivo oxidative flux measurements in either group (P>0.02), consistent with resolution of the T2D-associated oxygen limitation previously observed at baseline in subjects with T2D. State 4 mitochondrial respiration also improved in muscle fibres ex vivo. Skeletal muscle vasculature content and calf blood flow increased in all participants with SLET (P<0.0040); oxygen extraction in the calf increased only in T2D (P=0.0461). SLET resolves the T2D-associated impairment of skeletal muscle in vivo mitochondrial oxidative flux potentially through improved effective blood flow/oxygen delivery.

Obstructive sleep apnea and pulmonary hypertension: a bidirectional relationship.

Citation:Mesarwi O, Malhotra A. Obstructive sleep apnea and pulmonary hypertension: a bidirectional relationship. J Clin Sleep Med. 2020;16(8):1223–1224.

The effect of supplemental oxygen on perioperative brain natriuretic peptide concentration in cardiac risk patients \u2013 a protocol for a prosprective randomized clinical trial

BackgroundElevated postoperative N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations are predictive for cardiac adverse events in noncardiac surgery. Studies indicate that supplemental oxygen decreases sympathetic nerve activity and might, therefore, improve cardiovascular function. Thus, we will test the effect of perioperative supplemental oxygen administration on NT-proBNP release after surgery.Methods/designWe will conduct a single-center, double-blinded, randomized trial at the Medical University of Vienna, including 260 patients with increased cardiac risk factors undergoing moderate- to high-risk noncardiac surgery. Patients will be randomly assigned to receive 80% versus 30% oxygen during surgery and for 2 h postoperatively. The primary outcome will be the difference in maximum NT-proBNP release after surgery.As secondary outcomes we will assess the effect of supplemental oxygen on postoperative maximum troponin T concentration, oxidation-reduction potential, von Willebrand factor concentration and perioperative fluid requirements. We will perform outcome measurements 2 h after surgery, on postoperative day 1 and on postoperative day 3. The NT-proBNP concentration and the oxidation-reduction potential will also be measured within 72 h before discharge.DiscussionOur trial should determine whether perioperative supplemental oxygen administration will reduce the postoperative release of NT-proBNP in patients with preoperative increased cardiovascular risk factors undergoing noncardiac surgery.Trial registrationClinicalTrials.gov, ID: NCT03366857. Registered on 8th December 2017.

Supplemental oxygen improves exercise capacity in IPF patients with exertional desaturation

The efficacy of supplemental oxygen during exercise remains unclear for patients with IPF, as there have been conflicting results from recent prospective studies with small sample sizes. This prospective, single-blind, randomized, crossover trial evaluated the efficacy of supplemental oxygen compared with placebo air during exercise in consecutive patients with IPF without resting hypoxaemia at initial evaluation. Patients with <90% SpO2 in a 6MWT using room air were randomly assigned to a CWRET at 80% of peak work rate with oxygen or placebo air gas via nasal cannula at 4 L/min. The primary endpoint was the effect of supplemental oxygen on endurance time. We recruited 72 consecutive patients (median age: 66.5 years, % FVC: 84.6%, % DLCO : 61.4%). Supplemental oxygen significantly increased the endurance time (340-424 s; P < 0.001) and minimum SpO2 (88.0-94.0%; P < 0.001) compared with placebo air. Furthermore, supplemental oxygen significantly improved dyspnoea and leg fatigue. In a multivariate linear regression analysis, the endurance time on air was an independent explanatory variable of the improvement rate of endurance time (P = 0.02). In mild-moderate IPF with exercise-induced hypoxaemia even without resting hypoxaemia, supplemental oxygen during exercise improved the endurance time, desaturation and subjective symptoms. Patients with shorter endurance times with placebo air showed better improvement with supplemental oxygen.

Effect of supplemental oxygen on development of retinopathy of prematurity

Effect of supplemental oxygen on development of retinopathy of prematurity

88Oxygen therapy in myocardial infarction patients with or without diabetes mellitus - A predefined subgroup analysis from the DETO2X-AMI trial

Abstract Background In diabetes, there is an interaction between hyperglycaemia and cellular hypoxia, which may induce oxidative stress. Oxygen therapy in patients with diabetes and myocardial infarction (MI) has not been studied. Purpose Our aim was to determine the effects of supplemental oxygen in MI patients with or without diabetes. Methods The DETermination of the role of Oxygen in suspected Acute Myocardial Infarction (DETO2X-AMI) trial randomised 6629 patients with suspected myocardial infarction (MI) to receive oxygen at 6 L/min for 6–12 hours or ambient air. In this prespecified analysis involving 5010 patients with confirmed MI, 934 had known diabetes (19%). The main composite endpoint was the effect of supplemental oxygen on all-cause death, rehospitalisation with MI, or heart failure at one year in patients with diabetes. Key secondary endpoint was the comparison between patients with or without diabetes. Results In patients with diabetes, the main composite endpoint occurred in 16.2% (72 of 445) of patients allocated to oxygen compared to 16.6% (81 of 489) allocated to ambient air (hazard ratio [HR] 0.93; 95% confidence interval [CI], 0.67–1.27, P=0.81) at one year (figure). There was no statistically significant difference for the individual components of the main composite endpoint, or the rate of cardiovascular death up to one year. In comparison, corresponding endpoints in patients without diabetes were similar between the treatment groups. However, when comparing patients according to diabetes status, event rates were significantly higher in the diabetic population (main composite endpoint: HR 1.60; 95% CI, 1.32–1.93, P&lt;0.01). Kaplan-Meier curves for main endpoint Conclusions Oxygen therapy in normoxemic MI patients did not significantly affect 1-year all-cause death, cardiovascular death, rehospitalisation with MI or heart failure, irrespective of underlying diabetes. Noteworthy, despite that the incidence of cardiovascular outcomes has declined substantially in patients with diabetes over the last decades, we still observed markedly increased event rates in patients with diabetes. Acknowledgement/Funding Swedish Heart-Lung Foundation; Swedish Research Council; Stockholm County Council

Supplemental Oxygen for Treatment of Infants With Obstructive Sleep Apnea.

Supplemental oxygen has been shown to decrease the frequency of obstructive respiratory events during sleep, but may result in alveolar hypoventilation. Limited information exists on the effect of supplemental oxygen on sleep and respiratory events in infants with obstructive sleep apnea (OSA). We conducted a retrospective study of infants with OSA who had sleep studies performed from 2007-2012. All infants underwent a room air diagnostic sleep study (RA-PSG), followed by a sleep study while breathing supplemental oxygen via nasal cannula (O₂-PSG) on a separate night. Infants with split-night studies or with inadequate sleep time were excluded. Fifty-nine infants met criteria for entry into analysis. The mean age of infants at the time of RA-PSG was 13.0 ± 11.7 weeks and at O₂-PSG was 15.4 ± 13.0 weeks. The obstructive AHI decreased from 19.7 ± 13.0 during RA-PSG to 10.6 ± 11.7 during O₂-PSG (P < .001). The duration of longest obstructive apnea increased from 11.0 ± 4.2 seconds to 13.4 ± 7.4 seconds (P = .01). The lowest saturation associated with obstructive apneas increased from 80.7 ± 6.8% to 90.0 ± 6.7% (P < .001). Carbon dioxide data showed no difference in ventilation after supplemental oxygen administration. There was no significant change in the spontaneous arousal index, however, the percentage of respiratory events associated with arousal increased from 20.7 ± 11.1% to 35.7 ± 19.7% (P < .001). Infants with OSA who received supplemental oxygen had a significant decrease in the frequency of obstructive respiratory events and improved oxygenation without adverse effect on alveolar ventilation. These data suggest that supplemental oxygen may be an effective treatment for infants with OSA who are not good candidates for continuous positive airway pressure or surgery. Brockbank J, Astudillo CL, Che D, Tanphaichitr A, Huang G, Tomko J, Simakajornboon N. Supplemental oxygen for treatment of infants with obstructive sleep apnea. J Clin Sleep Med. 2019;15(8):1115-1123.

Effects of supplemental oxygen on cardiovascular magnetic resonance water proton relaxation time constant measurements (T1, T2 and T2*)

ObjectiveTo study, the effects of supplemental oxygen on the measurement of native cardiovascular water proton relaxation time constants using commercially available protocols. MethodsT1, T2 and T2* relaxation time constant mapping were performed in twelve volunteers at 1.5 T breathing room air and supplemental oxygen supplied by nasal cannula and a non-rebreather mask. Regions-of-interest were drawn for quantitative measurements in the bloodpool of each ventricle and atria as well as septal myocardium. The effects of supplemental oxygen were investigated statistically using a mixed model analysis of variance. Intra- and inter-observer reproducibility were assessed using the Intraclass Correlation Coefficient and Coefficient of Variation. ResultsBlood T1 relaxation time constants in the left ventricle (T1 change = −241.0 ms) and left atrium (T1 change = −247.0 ms) decreased significantly in every subject after oxygen inhalation with a non-rebreather mask (p < 0.001). No significant changes of T1 in the right side of the heart were detected after oxygen inhalation with the non-rebreather mask (p = 0.345). Oxygen inhalation with nasal cannula did not significantly change blood T1 in the study (p = 0.497). No significant changes in myocardial T1 (p = 0.390), T2 (p = 0.960) or T2* (p = 0.438) were observed with supplemental oxygen supplied by nasal cannula or the non-rebreather mask. Results were similar in mid-short-axis and horizontal long-axis acquisitions. ConclusionSupplemental oxygen does not affect myocardial relaxation time constant measurements with current protocols. On the other hand, blood T1 measurements with the inhalation of supplemental oxygen supplied by a non-rebreather mask change significantly and could affect myocardial tissue characterization if used for the calculation of extracellular volume. Additionally, current relaxation time constant mapping protocols do not reproducibly detect myocardial T1 changes with supplemental oxygen inhalation.

Effect of Supplemental Oxygen on Blood Pressure in Obstructive Sleep Apnea (SOX). A Randomized Continuous Positive Airway Pressure Withdrawal Trial.

Obstructive sleep apnea (OSA) is associated with systemic hypertension. Either overnight intermittent hypoxia, or the recurrent arousals that occur in OSA, could cause the daytime increases in blood pressure (BP). To establish the role of intermittent hypoxia in the increased morning BP in patients with OSA. Randomized, double-blinded, crossover trial assessing the effects of overnight supplemental oxygen versus air (sham) on morning BP, after continuous positive airway pressure (CPAP) withdrawal in patients with moderate to severe OSA. The primary outcome was the change in home morning BP after CPAP withdrawal for 14 nights, oxygen versus air. Secondary outcomes included oxygen desaturation index (ODI), apnea-hypopnea index (AHI), subjective sleepiness (Epworth Sleepiness Scale score), and objective sleepiness (Oxford Sleep Resistance Test). Supplemental oxygen virtually abolished the BP rise after CPAP withdrawal and, compared with air, significantly reduced the rise in mean systolic BP (-6.6 mm Hg; 95% confidence interval [CI], -11.3 to -1.9; P = 0.008), mean diastolic BP (-4.6 mm Hg; 95% CI, -7.8 to -1.5; P = 0.006), and median ODI (-23.8/h; interquartile range, -31.0 to -16.3; P < 0.001) after CPAP withdrawal. There was no significant difference, oxygen versus air, in AHI, subjective sleepiness, or objective sleepiness. Supplemental oxygen virtually abolished the rise in morning BP during CPAP withdrawal. Supplemental oxygen substantially reduced intermittent hypoxia, but had a minimal effect on markers of arousal (including AHI), subjective sleepiness, or objective sleepiness. Therefore intermittent hypoxia, and not recurrent arousals, appears to be the dominant cause of daytime increases in BP in OSA.