Perioperative Supplemental Oxygen for the Prevention of Surgical Site Infection After Cesarean Section: A Systematic Review of Existing Literature.

Initial systematic reviews demonstrated the reduction of surgical site infection (SSI) following perioperative oxygen supplementation. SSI among colorectal surgeries was reduced by more than 50% with high-flow oxygen. However, recent randomized trials are coming up with conflicting results. The objective of this review was to comprehend whether the application of perioperative supplemental oxygen decreased the hazard of SSI following cesarean delivery. The initial search identified 95 studies. After screening title and abstracts 59 studies were included, and 33 studies were found to be relevant after checking eligibility. After a careful analysis, five articles were found fit for this systematic review. Extracted information included study design and methodology, the cumulative incidence of post-cesarean SSI following supplemental oxygen, the odds ratio, and associated variability for all factors considered in univariate and/or multivariate analysis. The cumulative incidence of the standard care group and supplemental oxygen group were comparable in all five studies with statistically significant differences. The secondary outcomes such as hospital readmission, wound separation, and intravenous antibiotics were similar in both groups as stated in the two studies. The rate of SSI in diabetics was 6.9% and 14.4% in the standard care group and supplemental oxygen group, respectively, as analyzed in a study. An increase in intra-operative blood loss was found to be the major risk factor leading to SSI. In one of the studies, Caucasian race, increased basal metabolic index, and prolonged surgery were associated with increased risk of SSI. There was no difference in neonatal umbilical artery pH resulting from supplemental oxygen during cesarean. The available literature is quite sufficient to prove that supplemental oxygen offers no added benefit in reducing post-cesarean SSI. Hence, we do not recommend its use for this purpose.

2023 Year in Review: Home Oxygen Therapy.

Long-term oxygen therapy (LTOT) is a treatment that involves the provision of supplemental oxygen to individuals with respiratory disease to correct hypoxemia in the post-acute care environment. Over 1.5 million adults in the United States use supplemental oxygen for various respiratory disorders. This paper explores literature published on LTOT from September 2022-September 2023. Upon the conclusion of this literature review, 4 distinct categories emerged. This paper highlights the significant findings associated with the 4 categories: supplemental oxygen and COVID-19, telemonitoring, LTOT equipment, and in-home high-flow nasal cannula.

A case of middle-aged central sleep apnea due to Joubert syndrome with different treatment effects of oxygen and acetazolamide.

We report a case of severe central sleep apnea incidentally diagnosed during polysomnography for suspected obstructive sleep apnea. Characteristic clinical features included episodic hyperventilation followed by apnea from hypocapnia, which did not follow a Cheyne-Stokes pattern. Combined with the identification of cerebellar and brainstem malformations known as the "molar tooth sign" on a brain MRI, developmental delay, and motor coordination problems, Joubert syndrome (a congenital disease) was first diagnosed at the age of 50 years. Central apneas were also observed during wakefulness, although not continuously. During sleep, continuous positive airway pressure and adaptive servo-ventilation were ineffective at the referring clinic and at our hospital. Supplemental oxygen decreased the frequency of central apneas and significantly shortened the duration of each central sleep apnea compared with room air. In contrast, the opposite response was observed with acetazolamide administration.

Treating sleep-disordered breathing of idiopathic pulmonary fibrosis patients with CPAP and nocturnal oxygen treatment. A pilot study : Sleep-disordered breathing treatment in IPF.

INTRODUCTION: Sleep-disordered breathing (SDB) is a major comorbidity in idiopathic pulmonary fibrosis (IPF) and is associated with a poor outcome. There is a lack of knowledge regarding the impact of SDB treatment on IPF. We assessed at one year: (1) the effect of CPAP and/or nocturnal oxygen therapy on IPF regarding lung function, blood mediators, and quality of life; (2) adherence to SDB treatment and SDB changes. METHODOLOGY: This is a prospective study of consecutive newly diagnosed IPF patients initiating anti-fibrotic treatment. Lung function, polysomnography, blood tests and quality of life questionnaires were performed at inclusion and after one year. Patients were classified as obstructive sleep apnoea (OSA), central sleep apnoea (CSA), and sleep-sustained hypoxemia (SSH). SDB therapy (CPAP and/or nocturnal oxygen therapy) was initiated if needed. RESULTS: Fifty patients were enrolled (36% had OSA, 22% CSA, and 12% SSH). CPAP was started in 54% of patients and nocturnal oxygen therapy in 16%. At one-year, polysomnography found improved parameters, though 17% of patients had to add nocturnal oxygen therapy or CPAP, while 33% presented SDB onset at this second polysomnography. CPAP compliance at one year was 6.74 h/night (SD 0.74). After one year, matrix metalloproteinase-1 decreased in OSA and CSA (p = 0.029; p = 0.027), C-reactive protein in OSA (p = 0.045), and surfactant protein D in CSA group (p = 0.074). There was no significant change in lung function. CONCLUSIONS: Treatment of SBD with CPAP and NOT can be well tolerated with a high compliance. IPF patients may exhibit SDB progression and require periodic re-assessment. Further studies to evaluate the impact of SDB treatment on lung function and serological mediators are needed.

Efficacy of supplemental oxygen in reducing the need for laser or intravitreal bevacizumab in preterm infants with stage 2 retinopathy of prematurity.

BACKGROUND: Retinopathy of prematurity (ROP) is a disease that affects preterm infants born younger than 30 weeks of gestation. The pathophysiology of ROP involves an initial vaso-obliterative phase followed by vaso-proliferative phase that leads to disease progression. The use of supplemental oxygen during the vaso-proliferative phase of ROP has been associated with reduced disease progression, but how this impacts the need for ROP treatment is unclear. The goal of this study was to compare the rate of laser or intravitreal bevacizumab after implementation of a new supplemental oxygen therapy protocol in preterm infants with stage 2 ROP. METHODS: This is a retrospective chart review of preterm infants diagnosed with stage 2 ROP at Riley Hospital for Children between 1/2017 and 12/2022. Patients diagnosed between 1/2017 and 6/2020 were classified as Cohort A, preprotocol implementation. Patients diagnosed from 8/2020 to 12/2022 were classified as Cohort B, postprotocol implementation. In Cohort A, oxygen saturation was kept at 91-95% through the entire hospitalization. In Cohort B, oxygen saturation was increased to 97-99% as soon as Stage 2 ROP was diagnosed. Statistical analyses were performed using chi-square and Student's T test, followed by multivariate analyses to determine the impact of the oxygen protocol on the need for ROP treatment. RESULTS: A total of 211 patients were diagnosed with stage 2 ROP between 1/2017 and 12/2022. Of those patients, 122 were before protocol implementation therapy (Cohort A), and 89 were after implementation of supplemental oxygen protocol (Cohort B). Gestational age was slightly higher in Cohort B (Cohort A 25.3 ± 1.9, Cohort B 25.8 ± 1.84, p = 0.04). There was no difference in birth weight, NEC, BPD, or survival. Cohort B had lesser need for invasive mechanical ventilation and higher days on CPAP during hospitalization. Notably, Cohort A had 67 (55%) patients treated with laser photocoagulation or intravitreal bevacizumab versus 20 (22%) patients in Cohort B (OR 0.19, 0.08-0.40). CONCLUSION: The need for laser photocoagulation or intravitreal bevacizumab was significantly decreased in high-risk patients treated with the supplemental oxygen protocol. This result supports the idea that targeted supplemental oxygen therapy to keep saturations between 97 and 99% can reduce disease progression in infants with stage 2 ROP and potentially decrease the burden of additional procedures.

Safety and feasibility pilot study of continuous low-dose maternal supplemental oxygen in fetal single ventricle heart disease.

OBJECTIVE: Fetuses with single ventricle physiology (SVP) exhibit reductions in fetal cerebral oxygenation, with associated delays in fetal brain growth and neurodevelopmental outcomes. Maternal supplemental oxygen (MSO) has been proposed to improve fetal brain growth, but current evidence on dosing, candidacy and outcomes is limited. In this pilot study, we evaluated the safety and feasibility of continuous low-dose MSO in the setting of SVP. METHODS: This single-center, open-label, pilot phase-1 safety and feasibility clinical trial included 25 pregnant individuals with a diagnosis of fetal SVP. Participants self-administered continuous MSO using medical-grade oxygen concentrators for up to 24 h per day from the second half of gestation until delivery. The primary aim was the evaluation of the safety profile and feasibility of MSO. A secondary preliminary analysis was performed to assess the impact of MSO on the fetal circulation using echocardiography and late-gestation cardiovascular magnetic resonance imaging. Early outcomes were assessed, including perinatal growth and preoperative brain injury, and neurodevelopmental outcomes were assessed at 18 months using the Bayley Scales of Infant and Toddler Development 3rd edition, and compared with those of a contemporary fetal SVP cohort (n = 217) that received the normal standard of care (SOC). RESULTS: Among the 25 participants, the median maternal age at conception was 35 years, and fetal SVP diagnoses included 16 with right ventricle dominant, eight with left ventricle dominant and one with indeterminate ventricular morphology. Participants started the trial at approximately 29 + 2 weeks' gestation and self-administered MSO for a median of 16.1 h per day for 63 days, accumulating a median of 1029 h of oxygen intake from enrolment until delivery. The only treatment-associated adverse events were nasal complications that were resolved typically by attaching a humidifier unit to the oxygen concentrator. No premature closure of the ductus arteriosus or unexpected fetal demise was observed. In the secondary analysis, MSO was not associated with any changes in fetal growth, middle cerebral artery pulsatility index, cerebroplacental ratio or head-circumference-to-abdominal-circumference ratio Z-scores over gestation compared with SOC. Although MSO was associated with changes in umbilical artery pulsatility index Z-score over the study period compared with SOC (P = 0.02), this was probably due to initial baseline differences in placental resistance. At late-gestation cardiovascular magnetic resonance imaging, MSO was not associated with an increase in fetal cerebral oxygen delivery. Similarly, no differences were observed in neonatal outcomes, including preoperative brain weight Z-score and brain injury, mortality by 18 months of age and neurodevelopmental outcomes at 18 months of age. CONCLUSIONS: This pilot phase-1 clinical trial indicates that low-dose MSO therapy is safe and well tolerated in pregnancies diagnosed with fetal SVP. However, our protocol was not associated with an increase in fetal cerebral oxygen delivery or improvements in early neurological or neurodevelopmental outcomes. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Supplemental oxygen requirement after tonsillectomy in children >3 years of age.

INTRODUCTION: The indications for postoperative admission after tonsillectomy in children >3 years of age are less well defined than for children <3 years old, and typically include severe obstructive sleep apnea (OSA), obesity, comorbidities, or behavioral factors. Inpatient care after tonsillectomy typically consists of respiratory monitoring and support, as respiratory compromise is the most common complication after pediatric tonsillectomy. We aim to evaluate risk factors associated with postoperative oxygen supplementation and to identify high risk populations within the admitted population who use additional resources or require additional interventions. METHODS: Retrospective chart review of patients between the ages of 3 and 18 years old who underwent tonsillectomy by four surgeons at a tertiary care children's hospital was performed. Data including demographics, comorbidities, surgical intervention, pre- and postoperative AHI, admission, postoperative oxygen requirement, and postoperative complications was collected and analyzed. RESULTS: There were 401 patients included in the analysis. Of the patients in this study, 65.59% were male, 43.39% were Latino, and 53.87% were ages 3 to 7. Of the 397 patients with a record for supplemental oxygen, 36 (9.07%) received supplemental oxygen. The LASSO regression odds ratios (OR) found to be important for modeling supplemental oxygen use (in decreasing order of magnitude) are BMI ≥35 (OR = 2.30), pre-op AHI >30 (OR = 2.28), gastrointestinal comorbidities (OR = 2.20), musculoskeletal comorbidities (OR = 1.91), cardiac comorbidities (OR = 1.20), pulmonary comorbidities (OR = 1.14), and BMI 30 to <35 (OR = 1.07). Female gender was found to be negatively associated with risk of supplemental oxygen use (OR = 0.84). Age, race, AHI ≥15-30, neurologic comorbidities, syndromic patients, admission reason, and undergoing other procedures concomitantly were not found to be associated with increased postoperative oxygen requirement. CONCLUSION: BMI ≥30, pre-op AHI >30, male gender, and gastrointestinal, musculoskeletal, cardiac, and pulmonary comorbidities are all associated with postoperative supplemental oxygen use. Age, race, AHI ≥15-30, neurologic comorbidities, syndromic patients, admission reason, and undergoing other procedures concomitantly were not found to be associated with increased postoperative oxygen requirement.

Apnoeic oxygenation during paediatric tracheal intubation: a systematic review and meta-analysis.

BACKGROUND: Supplemental oxygen administration by apnoeic oxygenation during laryngoscopy for tracheal intubation is intended to prolong safe apnoea time, reduce the risk of hypoxaemia, and increase the success rate of first-attempt tracheal intubation under general anaesthesia. This systematic review examined the efficacy and effectiveness of apnoeic oxygenation during tracheal intubation in children. METHODS: This systematic review and meta-analysis included randomised controlled trials and non-randomised studies in paediatric patients requiring tracheal intubation, evaluating apnoeic oxygenation by any method compared with patients without apnoeic oxygenation. Searched databases were MEDLINE, Embase, Cochrane Library, CINAHL, ClinicalTrials.gov, International Clinical Trials Registry Platform (ICTRP), Scopus, and Web of Science from inception to March 22, 2023. Data extraction and risk of bias assessment followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) recommendation. RESULTS: After initial selection of 40 708 articles, 15 studies summarising 9802 children were included (10 randomised controlled trials, four pre-post studies, one prospective observational study) published between 1988 and 2023. Eight randomised controlled trials were included for meta-analysis (n=1070 children; 803 from operating theatres, 267 from neonatal intensive care units). Apnoeic oxygenation increased intubation first-pass success with no physiological instability (risk ratio [RR] 1.27, 95% confidence interval [CI] 1.03-1.57, P=0.04, I2=0), higher oxygen saturation during intubation (mean difference 3.6%, 95% CI 0.8-6.5%, P=0.02, I2=63%), and decreased incidence of hypoxaemia (RR 0.24, 95% CI 0.17-0.33, P<0.01, I2=51%) compared with no supplementary oxygen administration. CONCLUSION: This systematic review with meta-analysis confirms that apnoeic oxygenation during tracheal intubation of children significantly increases first-pass intubation success rate. Furthermore, apnoeic oxygenation enables stable physiological conditions by maintaining oxygen saturation within the normal range. CLINICAL TRIAL REGISTRATION: Protocol registered prospectively on PROSPERO (registration number: CRD42022369000) on December 2, 2022.

A Double-Blind, Randomized, Placebo-Controlled Pilot Study examining an Oxygen Nanobubble Beverage for 16.1-km Time Trial and Repeated Sprint Cycling Performance.

There is growing interest of ergogenic aids that deliver supplemental oxygen during exercise and recovery, however, breathing supplemental oxygen via specialist facemasks is often not feasible. Therefore, this study investigated the effect of an oxygen-nanobubble beverage during submaximal and repeated sprint cycling. In a double-blind, randomized, placebo-controlled study, 10 male cyclists (peak aerobic capacity, 56.9 ± 6.1 mL·kg-1·min-1; maximal aerobic power, 385 ± 25 W) completed submaximal or maximal exercise after consuming an oxygen-nanobubble (O2) or placebo (PLA) beverage. Submaximal trials comprised 30-min of steady-state cycling at 60% peak aerobic capacity and 16.1-km time-trial (TT). Maximal trials involved 4 × 30 s Wingate tests interspersed by 4-min recovery. Time-to-completion during the 16.1-km TT was 2.4% faster after O2 compared with PLA (95% CI = 0.7-4.0%, p = 0.010, d = 0.41). Average power for the 16.1-km TT was 4.1% higher for O2 vs. PLA (95% CI = 2.1-7.3%, p = 0.006, d = 0.28). Average peak power during the repeated Wingate tests increased by 7.1% for O2 compared with PLA (p = 0.002, d = 0.58). An oxygen-nanobubble beverage improves performance during submaximal and repeated sprint cycling, therefore may provide a practical and effective ergogenic aid for competitive cyclists.

Lower versus higher oxygen targets after resuscitation from out-of-hospital cardiac arrest: A systematic review and meta-analysis of randomized controlled trials.

PURPOSE: To update the existing evidence and gain further insight into effects of lower versus higher oxygen targets on the outcomes in patients resuscitated from out-of-hospital cardiac arrest (OHCA). METHODS: We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing lower versus higher oxygen targets on the outcomes among adults resuscitated from OHCA. The primary outcome was short-term survival (in hospital or within 30 days). Subgroup analyses were performed according to timing of study interventions. RESULTS: Seven RCTs with 1454 patients were finally included. The short-term survival did not differ between the two groups with a relative risk (RR) of 0.98 (95% CI, 0.86 to 1.11). There were no significant differences in survival at longest follow-up (RR, 1.01; 95% CI, 0.91 to 1.14), favorable neurological outcome (RR, 1.00; 95% CI, 0.91 to 1.11), length of intensive care unit stay (mean difference, -4.94 h; 95% CI, -14.83 to 4.96 h), or risk of re-arrest (RR, 0.68; 95% CI, 0.21 to 2.19). The quality of evidence ranged from moderate to very low. CONCLUSION: Current evidence suggests that targeting a lower or higher oxygen therapy in patients after resuscitation from OHCA results in similar short-term survival and other clinical outcomes.

The Diagnostic Utility of Artificial Intelligence-Guided Computed Tomography-Based Severity Scores for Predicting Short-Term Clinical Outcomes in Adults with COVID-19 Pneumonia.

Chest computed tomography (CT) imaging with the use of an artificial intelligence (AI) analysis program has been helpful for the rapid evaluation of large numbers of patients during the COVID-19 pandemic. We have previously demonstrated that adults with COVID-19 infection with high-risk obstructive sleep apnea (OSA) have poorer clinical outcomes than COVID-19 patients with low-risk OSA. In the current secondary analysis, we evaluated the association of AI-guided CT-based severity scores (SSs) with short-term outcomes in the same cohort. In total, 221 patients (mean age of 52.6 ± 15.6 years, 59% men) with eligible chest CT images from March to May 2020 were included. The AI program scanned the CT images in 3D, and the algorithm measured volumes of lobes and lungs as well as high-opacity areas, including ground glass and consolidation. An SS was defined as the ratio of the volume of high-opacity areas to that of the total lung volume. The primary outcome was the need for supplemental oxygen and hospitalization over 28 days. A receiver operating characteristic (ROC) curve analysis of the association between an SS and the need for supplemental oxygen revealed a cut-off score of 2.65 on the CT images, with a sensitivity of 81% and a specificity of 56%. In a multivariate logistic regression model, an SS > 2.65 predicted the need for supplemental oxygen, with an odds ratio (OR) of 3.98 (95% confidence interval (CI) 1.80-8.79; p < 0.001), and hospitalization, with an OR of 2.40 (95% CI 1.23-4.71; p = 0.011), adjusted for age, sex, body mass index, diabetes, hypertension, and coronary artery disease. We conclude that AI-guided CT-based SSs can be used for predicting the need for supplemental oxygen and hospitalization in patients with COVID-19 pneumonia.

Incidence of postoperative opioid-induced respiratory depression episodes in patients on room air or supplemental oxygen: a post-hoc analysis of the PRODIGY trial.

BACKGROUND: Supplemental oxygen (SO) potentiates opioid-induced respiratory depression (OIRD) in experiments on healthy volunteers. Our objective was to examine the relationship between SO and OIRD in patients on surgical units. METHODS: This post-hoc analysis utilized a portion of the observational PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) trial dataset (202 patients, two trial sites), which involved blinded continuous pulse oximetry and capnography monitoring of postsurgical patients on surgical units. OIRD incidence was determined for patients receiving room air (RA), intermittent SO, or continuous SO. Generalized estimating equation (GEE) models, with a Poisson distribution, a log-link function and time of exposure as offset, were used to compare the incidence of OIRD when patients were receiving SO vs RA. RESULTS: Within the analysis cohort, 74 patients were always on RA, 88 on intermittent and 40 on continuous SO. Compared with when on RA, when receiving SO patients had a higher risk for all OIRD episodes (incidence rate ratio [IRR] 2.7, 95% confidence interval [CI] 1.4-5.1), apnea episodes (IRR 2.8, 95% CI 1.5-5.2), and bradypnea episodes (IRR 3.0, 95% CI 1.2-7.9). Patients with high or intermediate PRODIGY scores had higher IRRs of OIRD episodes when receiving SO, compared with RA (IRR 4.5, 95% CI 2.2-9.6 and IRR 2.3, 95% CI 1.1-4.9, for high and intermediate scores, respectively). CONCLUSIONS: Despite oxygen desaturation events not differing between SO and RA, SO may clinically promote OIRD. Clinicians should be aware that postoperative patients receiving SO therapy remain at increased risk for apnea and bradypnea. TRIAL REGISTRATION: Clinicaltrials.gov: NCT02811302, registered June 23, 2016.

Noninvasive Assessment of Impaired Gas Exchange with the Alveolar Gas Monitor Predicts Clinical Deterioration in COVID-19 Patients.

BACKGROUND AND OBJECTIVE: The COVID-19 pandemic magnified the importance of gas exchange abnormalities in early respiratory failure. Pulse oximetry (SpO2) has not been universally effective for clinical decision-making, possibly because of limitations. The alveolar gas monitor (AGM100) adds exhaled gas tensions to SpO2 to calculate the oxygen deficit (OD). The OD parallels the alveolar-to-arterial oxygen difference (AaDO2) in outpatients with cardiopulmonary disease. We hypothesized that the OD would discriminate between COVID-19 patients who require hospital admission and those who are discharged home, as well as predict need for supplemental oxygen during the index hospitalization. METHODS: Patients presenting with dyspnea and COVID-19 were enrolled with informed consent and had OD measured using the AGM100. The OD was then compared between admitted and discharged patients and between patients who required supplemental oxygen and those who did not. The OD was also compared to SpO2 for each of these outcomes using receiver operating characteristic (ROC) curves. RESULTS: Thirty patients were COVID-19 positive and had complete AGM100 data. The mean OD was significantly (p = 0.025) higher among those admitted 50.0 ± 20.6 (mean ± SD) vs. discharged 27.0 ± 14.3 (mean ± SD). The OD was also significantly (p < 0.0001) higher among those requiring supplemental oxygen 60.1 ± 12.9 (mean ± SD) vs. those remaining on room air 25.2 ± 11.9 (mean ± SD). ROC curves for the OD demonstrated very good and excellent sensitivity for predicting hospital admission and supplemental oxygen administration, respectively. The OD performed better than an SpO2 threshold of <94%. CONCLUSIONS: The AGM100 is a novel, noninvasive way of measuring impaired gas exchange for clinically important endpoints in COVID-19.

Efficact of Supplemental Oxygen During Procedural Sedation and Analgesia in Elderly Patients in the Emergency Department.

BACKGROUND: The use of supplemental oxygen (SO) for procedural sedation and analgesia (PSA) is recommended in many guidelines, but the evidence of SO for the elderly is limited. OBJECTIVES: This study aimed to compare the incidence of hypoxia with or without SO in PSA for the elderly patients. METHODS: We prospectively collected data on all patients undergoing PSA in the emergency department (ED) from May 2017 through December 2021. These data are from the Japanese Procedural SedaTion and Analgesia Registry. We included all elderly patients (65 years and older) who received PSA in the ED. We performed propensity score analysis for inverse probability of treatment weighting (IPTW) to balance the baseline characteristics. The primary outcome was the incidence of hypoxia (SpO2 < 90%), and the secondary outcome was the incidence of bag-valve mask ventilation. RESULTS: Among 1465 patients in the registry, we included 816 (55.7%) patients in the analysis. After propensity score method for IPTW, the distributions of confounders were closely balanced between the two groups. The incidence of hypoxia was significantly lower in the SO group compared with the non-SO group (6.2% vs. 19.3%; difference -13.1%; 95% confidence interval [CI] -9.8 to -16.4; p < 0.001). SO was also associated with a lower incidence of bag-valve mask ventilation (5.2% vs. 15.4%; difference -10.2%; 95% CI -7.1 to -13.2; p < 0.001). CONCLUSIONS: In a propensity-matched analysis, SO was associated with a lower incidence of hypoxia in elderly patients during ED PSA.

Trend of SARS-Cov-2-Specific IgG Antibody Titers Among COVID-19 Pneumonia Patients: A Nine-Month Follow-Up.

Introduction Understanding the dynamics of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin G (IgG) spike antibody titers after natural infection is important for understanding immunological memory. This longitudinal study was conducted to assess the trend in serum SARS-CoV-2 IgG spike antibody titers in a cohort of recovered cases up to nine months after SARS infection. Materials and methods We examined the neutralizing antibody response (IgG spike) in serum samples from a cohort of 86 SARS-CoV-2 quantitative polymerase chain reaction (qPCR)-confirmed infection, comprising cases having minor COVID-19 pneumonia and severity, which was determined by CT severity scores. Patients were enrolled in August/September 2020 and serum samples have been processed at one, three, six, and nine months. CT severity scores were rated between 1-25 and antibody titers≥ 1.4 were considered positive. Results The mean anti-SARS-CoV-2-specific IgG antibody titers at one month, three months, six months, and nine months were 22.02 ± 18.36, 14.62 ± 12.61, 8.93 ± 8.10, and 3.86 ± 5.70, respectively. The difference was statistically significant. The seropositivity rates (titer ≥1.4 IU) were 93.02%, 82.56%, 76.74%, and 58.14% at one, three, six, and nine months after infection, respectively. Cases with severe CT severity scores showed significantly higher mean antibody levels at all follow-up visits.

Clinical outcomes by supplemental oxygen use in remdesivir-treated, hospitalised adults with COVID-19.

BACKGROUND: Clinical trials show different effects of remdesivir on clinical outcomes relative to COVID-19 severity at hospital admission; in Europe, there are few real-world data. METHODS: A multicentre, multinational retrospective cohort study in adult patients hospitalised with PCR-confirmed COVID-19 was conducted to understand remdesivir clinical use in different countries and to describe outcomes for patients receiving remdesivir stratified by oxygen use. Primary endpoints were all-cause mortality at day 28 and hospitalisation duration. Patients were categorised by baseline disease severity: no supplemental oxygen (NSO); low flow oxygen ≤ 6 litres (l)/minute (LFO); high flow oxygen > 6 l/minute (HFO). RESULTS: Four hundred and forty-eight (448) patients (72 [16.1%] HFO; 295 [65.8%] LFO; 81 (18.1%] NSO) were included; median age was 65 years and 64% were male. Mortality was higher in patients on HFO (rate 23.6%) compared to LFO (10.2%; p = 0.001) or NSO (6.2%; p = 0.002). Duration of hospitalisation was longer in patients on HFO (13 days) compared to LFO (9 days; p = 0.003) and NSO (9 days; p = 0.021). Patients who initiated remdesivir ≥ 2 days compared to within a day of hospitalisation had a 4.2 times higher risk of death, irrespective of age, sex, comorbidities, and oxygen support at baseline. Requirement for mechanical ventilation/ECMO and readmission within 28 days of discharge was similar across groups. Remdesivir use and outcomes differed by country. CONCLUSIONS: A higher mortality rate and duration of hospitalisation was seen in remdesivir-treated COVID-19 patients on HFO compared to LFO and NSO. Initiation of remdesivir upon admission as opposed to delayed initiation has a mortality benefit. CLINICAL TRIALS REGISTRATION: NCT04847622.

Frequency and risk factors for failed weaning from supplemental oxygen therapy after general anesthesia at a postanesthesia care unit: a retrospective cohort study.

BACKGROUND: Patients are administered supplemental oxygen upon emergence from general anesthesia against the risk of hypoxia. However, few studies have assessed the weaning from supplemental oxygen therapy. This study investigated the frequency and risk factors of failure to discontinue supplemental oxygen at a postanesthesia care unit (PACU). METHODS: This retrospective cohort study was conducted in a tertiary hospital. We reviewed the medical records of adult patients admitted to the PACU after general anesthesia for elective surgery between January 2022 and November 2022. The primary endpoint was the frequency of failed weaning from supplemental oxygen therapy at PACU. A failed weaning was defined as oxygen saturation (SpO2) < 92% after discontinuing oxygen administration. The rate of failed discontinuation of supplemental oxygen at the PACU was assessed. Demographics, intraoperative, and postoperative factors were explored to determine potential associations with failed weaning from supplemental oxygen therapy using logistic regression analysis. RESULTS: We analyzed 12,109 patients. We identified 842 cases of failed weaning from supplemental oxygen therapy, with a frequency of 1:14 (95% confidence interval [CI], 1:15-1:13). Risk factors that showed the strongest associations with failed weaning included postoperative hypothermia (odds ratio [OR], 5.42; 95% CI, 4.40-6.68; P < 0.001), major abdominal surgery (OR, 4.04; 95% CI, 3.29-4.99; P < 0.001), and preoperative SpO2 < 92% in room air (OR, 3.15; 95% CI, 2.09-4.64; P < 0.001). CONCLUSION: In the analysis of more than 12,000 general anesthetics, an overall risk of failed weaning from supplemental oxygen therapy of 1:14 was observed. The identified risk factors may help determine the discontinuation of supplemental oxygen administration at PACU. TRIAL REGISTRATION: Not applicable.

Hemodynamic effects of intraoperative 30% versus 80% oxygen concentrations: an exploratory analysis.

Background: Supplemental oxygen leads to an increase in peripheral vascular resistance which finally increases systemic blood pressure in healthy subjects and patients with coronary artery disease, heart failure, undergoing heart surgery, and with sepsis. However, it is unknown whether this effect can also be observed in anesthetized patients having surgery. Thus, we evaluated in this exploratory analysis of a randomized controlled trial the effect of 80% versus 30% oxygen on intraoperative blood pressure and heart rate. Methods: We present data from a previous study including 258 patients, who were randomized to a perioperative inspiratory FiO2 of 0.8 (128 patients) versus 0.3 (130 patients) for major abdominal surgery. Continuous arterial blood pressure values were recorded every three seconds and were exported from the electronic anesthesia record system. We calculated time-weighted average (TWA) and Average Real Variability (ARV) of mean arterial blood pressure and of heart rate. Results: There was no significant difference in TWA of mean arterial pressure between the 80% (80 mmHg [76, 85]) and 30% (81 mmHg [77, 86]) oxygen group (effect estimate -0.16 mmHg, CI -1.83 to 1.51; p = 0.85). There was also no significant difference in TWA of heart rate between the 80 and 30% oxygen group (median TWA of heart rate in the 80% oxygen group: 65 beats.min-1 [58, 72], and in the 30% oxygen group: 64 beats.min-1 [58; 70]; effect estimate: 0.12 beats.min-1, CI -2.55 to 2.8, p = 0.94). Also for ARV values, no significant differences between groups could be detected. Conclusion: In contrast to previous results, we did not observe a significant increase in blood pressure or a significant decrease in heart rate in patients, who received 80% oxygen as compared to patients, who received 30% oxygen during surgery and for the first two postoperative hours. Thus, hemodynamic effects of supplemental oxygen might play a negligible role in anesthetized patients. Clinical Trail Registration: https://clinicaltrials.gov/ct2/show/NCT03366857?term=vienna&cond=oxygen&draw=2&rank=1.

Oxygen Therapy in COPD.

Long-term oxygen therapy (LTOT) is a mainstay treatment for patients with severe resting hypoxemia secondary to chronic respiratory conditions including COPD. The evidence for LTOT is based on two trials that are now several decades old but have been insufficiently revisited. Therefore, many questions remain about precisely which patients experience the most benefit from LTOT, as well as how to define that benefit. Most studies have examined LTOT's effect on longevity rather than its impact on quality of life. In addition, many challenges exist in training both clinicians and patients on best practices for LTOT and associated equipment. Reimbursement policies have reduced the kinds of equipment available to the LTOT patient community, presenting additional challenges. This paper will review the current evidence for LTOT in COPD, the challenges involved with providing optimal therapy, and potential avenues of modernizing this essential intervention.