Oxygen Requirements In Patients Research Articles

432. Predictors for oxygen requirements in patients hospitalized with COVID-19 during the Omicron surge, January 2022

Abstract Background Omicron replaced Delta as the predominant SARS-CoV-2 variant during December 2021. The period of escalating hospitalizations in January 2022 is a window to study the impact of vaccination on disease severity. Edward Hospital COVID admissions & CDC Nowcast variant proportions during January 2022 Left: CDC Nowcast showing Omicron accounted for >95% new infections week ending January 8, 2022 , Right: Edward Hospital COVID admissions from 6/2021-6/2022. Edward Hospital is a 359 bed community hospital in Naperville, IL. Methods Retrospective chart review of adults admitted to Edward Hospital medical units or ICU with COVID during January 2022, for risk factors: age, body mass index (BMI), immunosuppression, gender, COVID vaccination, and medical conditions as predictors for disease severity, measured by level of supplemental oxygen requirements (O2) maintained > 24 hours. Outcomes were (1) any O2 if not on home O2, (2) high level O2 [ high flow (HF), noninvasive (NIV), or mechanical ventilation (MV)], and (3) hospital death or MV. Methods Input and output variables measured in retrospective chart review Results O2 requirements were (1) any O2 in 133 of 379 admissions not on home O2 and (2) high level in 58 of 393 all admitted. 28 died, 15 on MV. Vaccination was within 5 months in 83 of 85 who had boosters and 16 of 144 who did not. In a multivariate analysis, factors associated with (1) any O2, (2) high level O2, and (3) hospital death or MV, (odds ratio [95%CI]), were being not fully vaccinated (7.86 [3.78-16.4], 5.17 [2.01-13.3], 5.21 [1.63-16.6]) compared to booster vaccinated, immunocompromised (2.79 [1.38-5.63]), 3.79 [1.66-8.67], 4.63 [1.72-12.5]), and age > 75 (2.85 [1.34-6.07]), 4.02 [1.47-11.2], 5.68 [1.49-21.7] ) compared to 50-64 years. Other factors associated with any O2 were BMI > 35 kg/m2 {35.0-39.9 (2.4 [1.09-5.26]), > 40.0 (3.29 [1.34-8.1]) compared to < 24.9} and age 65-74 (2.13 [1.03-4.38]) compared to 50- 64 years; with high level O2 were cardiomyopathy (2.11 [1.04-4.32) and male gender (1.93 [1.01-3.7]); with MV or death were cardiomyopathy (2.67 [1.11-6.42]) and CKD (3.17 [1.27-7.96]). Association was not found with (1), (2), or (3) for no booster if vaccinated (1.07 [0.522-2.21], 1.08 [0.415-2.81], 0.992 [0.328-3.0]), age 50-64 compared to 18-54 years (1.04 [0.495-2.2], 1.2 [0.418-3.43], 0.355 [0.037-3.75]), or other conditions. Multivariate analysis for factors associated with any O2 requirements in patients not on home O2 Top: Oxygen requirements and hospital deaths for patients not on hone O2, Multivariate analysis for risk factors associated with any O2 requirements in patients not on home O2 Bottom: O2 requirements and hospital deaths for patients on home O2 Multivariate analysis for factors associated with high level O2 and the composite of MV or hospital death Top: Factors associated with high level O2 (high flow, noninvasive or mechanical ventilation) Bottom: Factors associated with mechanical ventilation or hospital death Secondary outcomes and associations Top: Pairwise association of vaccination status with age, BMI, immunosuppression, and time since last vaccine Bottom: Vaccination rates by age groups in Will and DuPage counties and estimation of relative risk using percentage vaccinated for each age group Conclusion Risk factors for hypoxia in patients hospitalized with COVID during the Omicron surge were not being fully vaccinated, immunosuppression, age > 65 years, and BMI > 35 mg/kg2. Boosters were not associated with less severe outcomes in vaccinated cases, suggesting immune memory plays a major role in averting severe disease. Summary Conclusions Literature Disclosures All Authors: No reported disclosures

Remdesivir in pregnant women with moderate to severe coronavirus disease 2019 (COVID-19): a retrospective cohort study.

Data on the efficacy of remdesivir in Coronavirus Disease 2019 (COVID-19) are limited in pregnant patients since they have been excluded from clinical trials. We aimed to investigate some clinical outcomes following remdesivir administration in pregnancy. This was a retrospective cohort study conducted on pregnant women with moderate to severe COVID-19. The enrolled patients were divided into two groups with and without remdesivir treatment. The primary outcomes of this study were the length of hospital and intensive care unit stay; respiratory parameters of hospital day 7 including respiratory rate, oxygen saturation, and mode of oxygen support; discharge until days 7 and 14, and need for home oxygen therapy. Secondary outcomes included some maternal and neonatal consequences. Eighty-one pregnant women (57 in the remdesivir group and 24 in the non-remdesivir group) were included. The two study groups were comparable according to the baseline demographic and clinical characteristics. Of the respiratory outcomes, remdesivir was significantly associated with a reduced length of hospital stay (p = 0.021) and also with a lower level of oxygen requirement in patients on low-flow oxygen [odds ratio (OR) 3.669]. Among the maternal consequences, no patients in the remdesivir group developed preeclampsia but three patients (12.5%) experienced this complication in the non-remdesivir group (p = 0.024). Furthermore, in patients with moderate COVID-19, the percentage of emergency termination was significantly lower in remdesivir group (OR 2.46). Our results demonstrated some probable benefits of remdesivir in respiratory and also maternal outcomes. Further investigations with a larger sample size should confirm these results.

Machine Learning Prediction for Supplemental Oxygen Requirement in Patients with COVID-19

Introduction:The coronavirus disease (COVID-19) poses an urgent threat to global public health and is characterized by rapid disease progression even in mild cases. In this study, we investigated whether machine learning can be used to predict which patients will have a deteriorated condition and require oxygenation in asymptomatic or mild cases of COVID-19.Method:This single-center, retrospective, observational study included COVID-19 patients admitted to the hospital from February 1, 2020, to May 31, 2020, and who were either asymptomatic or presented with mild symptoms and did not require oxygen support on admission. Data on patient characteristics and vital signs were collected upon admission. We used seven machine learning algorithms, assessed their capability to predict exacerbation, and analyzed important influencing features using the best algorithm.Results:In total, 210 patients were included in the study. Among them, 43 (19%) required oxygen therapy. Of all the models, the logistic regression model had the highest accuracy and precision. Logistic regression analysis showed that the model had an accuracy of 0.900, precision of 0.893, and recall of 0.605. The most important parameter for predictive capability was SpO2, followed by age, respiratory rate, and systolic blood pressure.Conclusion:In this study, we developed a machine learning model that can be used as a triage tool by clinicians to detect high-risk patients and disease progression earlier. Prospective validation studies are needed to verify the application of the tool in clinical practice.

Prediction of oxygen requirement in patients with COVID-19 using a pre-trained chest radiograph xAI model: efficient development of auditable risk prediction models via a fine-tuning approach

Risk prediction requires comprehensive integration of clinical information and concurrent radiological findings. We present an upgraded chest radiograph (CXR) explainable artificial intelligence (xAI) model, which was trained on 241,723 well-annotated CXRs obtained prior to the onset of the COVID-19 pandemic. Mean area under the receiver operating characteristic curve (AUROC) for detection of 20 radiographic features was 0.955 (95% CI 0.938–0.955) on PA view and 0.909 (95% CI 0.890–0.925) on AP view. Coexistent and correlated radiographic findings are displayed in an interpretation table, and calibrated classifier confidence is displayed on an AI scoreboard. Retrieval of similar feature patches and comparable CXRs from a Model-Derived Atlas provides justification for model predictions. To demonstrate the feasibility of a fine-tuning approach for efficient and scalable development of xAI risk prediction models, we applied our CXR xAI model, in combination with clinical information, to predict oxygen requirement in COVID-19 patients. Prediction accuracy for high flow oxygen (HFO) and mechanical ventilation (MV) was 0.953 and 0.934 at 24 h and 0.932 and 0.836 at 72 h from the time of emergency department (ED) admission, respectively. Our CXR xAI model is auditable and captures key pathophysiological manifestations of cardiorespiratory diseases and cardiothoracic comorbidities. This model can be efficiently and broadly applied via a fine-tuning approach to provide fully automated risk and outcome predictions in various clinical scenarios in real-world practice.

Predicting oxygen requirements in patients with coronavirus disease 2019 using an artificial intelligence-clinician model based on local non-image data.

When facing unprecedented emergencies such as the coronavirus disease 2019 (COVID-19) pandemic, a predictive artificial intelligence (AI) model with real-time customized designs can be helpful for clinical decision-making support in constantly changing environments. We created models and compared the performance of AI in collaboration with a clinician and that of AI alone to predict the need for supplemental oxygen based on local, non-image data of patients with COVID-19. We enrolled 30 patients with COVID-19 who were aged >60 years on admission and not treated with oxygen therapy between December 1, 2020 and January 4, 2021 in this 50-bed, single-center retrospective cohort study. The outcome was requirement for oxygen after admission. The model performance to predict the need for oxygen by AI in collaboration with a clinician was better than that by AI alone. Sodium chloride difference >33.5 emerged as a novel indicator to predict the need for oxygen in patients with COVID-19. To prevent severe COVID-19 in older patients, dehydration compensation may be considered in pre-hospitalization care. In clinical practice, our approach enables the building of a better predictive model with prompt clinician feedback even in new scenarios. These can be applied not only to current and future pandemic situations but also to other diseases within the healthcare system.

Machine Learning Prediction for Supplemental Oxygen Requirement in Patients with COVID-19

The coronavirus disease (COVID-19) poses an urgent threat to global public health and is characterized by rapid disease progression even in mild cases. In this study, we investigated whether machine learning can be used to predict which patients will have a deteriorated condition and require oxygenation in asymptomatic or mild cases of COVID-19.This single-center, retrospective, observational study included COVID-19 patients admitted to the hospital from February 1, 2020, to May 31, 2020, and who were either asymptomatic or presented with mild symptoms and did not require oxygen support on admission. Data on patient characteristics and vital signs were collected upon admission. We used seven machine learning algorithms, assessed their capability to predict exacerbation, and analyzed important influencing features using the best algorithm.In total, 210 patients were included in the study. Among them, 43 (19%) required oxygen therapy. Of all the models, the logistic regression model had the highest accuracy and precision. Logistic regression analysis showed that the model had an accuracy of 0.900, precision of 0.893, and recall of 0.605. The most important parameter for predictive capability was SpO2, followed by age, respiratory rate, and systolic blood pressure.In this study, we developed a machine learning model that can be used as a triage tool by clinicians to detect high-risk patients and disease progression earlier. Prospective validation studies are needed to verify the application of the tool in clinical practice.

Early Oxygen Requirement in Patients with Mild-to-Moderate COVID-19 Who Received Regdanvimab after Delta-Variant Outbreak.

BackgroundRegdanvimab is a monoclonal antibody targeted against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and a treatment option for patients with mild-to moderate coronavirus disease 2019 (COVID-19). However, there has been limited information on the clinical effectiveness of regdanvimab in the Delta variant of SARS-CoV-2. Therefore, we aimed to investigate the effectiveness of regdanvimab after the Delta variant was dominant using chronological analysis of regdanvimab use in a real-world setting.Materials and MethodsThe electrical medical records of patients infected with mild-to-moderate COVID-19 who received regdanvimab within 7 days of symptom onset were reviewed before (February – June 2021) and after (August – November 2021) the Delta variant became predominant in Korea. Clinical outcomes were assessed by the need for oxygen supplementation, time from symptom onset to oxygen requirement, in-hospital mortality, and length of hospitalization. To match the difference between the basic characteristics of the two groups, the clinical outcomes were compared again after 1 : 1 propensity score matching.ResultsPatients treated with regdanvimab in the Delta-predominant group were more likely to require oxygen supplementation (17.5% vs. 6.0%, P = 0.019) and had shorter times from symptom onset to supplemental oxygen use (mean ± standard deviation [SD]: 5.8 ± 2.8 vs. 10.0 ± 3.7, P = 0.007) than those in the control group. After propensity score matching, the percentage of patient requiring oxygen supplementation was higher (15.2% vs. 6.1%, P = 0.156), while the time from symptom onset to oxygen supplementation was significantly shorter in the Delta-predominant group (mean ± SD: 4.9 ± 2.1 vs. 10.0 ± 3.7, P = 0.007) than that in the control group.ConclusionConsidering that high proportion of vaccinated patients in the Delta-predominant group, this finding suggests the uncertainty whether the effect of regdanvimab is maintained even during the Delta-predominant period. It is hence necessary to continuously monitor the effectiveness of regdanvimab as new SARS-CoV-2 variants emerge.

P5‐94: The usefulness of a combination of age, body mass index, and blood urea nitrogen as prognostic factors in predicting oxygen requirements in patients with coronavirus disease 2019

P5‐94: The usefulness of a combination of age, body mass index, and blood urea nitrogen as prognostic factors in predicting oxygen requirements in patients with coronavirus disease 2019

The usefulness of a combination of age, body mass index, and blood urea nitrogen as prognostic factors in predicting oxygen requirements in patients with coronavirus disease 2019

IntroductionRisk factors for seriously ill coronavirus disease 19 (COVID-19) patients have been reported in several studies. However, to date, few studies have reported simple risk assessment tools for distinguishing patients becoming severely ill after initial diagnosis. Hence, this study aimed to develop a simple clinical risk nomogram predicting oxygenation risk in patients with COVID-19 at the first triage. MethodsThis retrospective study involved a chart review of the medical records of 84 patients diagnosed with COVID-19 between February 2020 and March 2021 at ten medical facilities. The patients were divided into requiring no oxygen therapy (non-severe group) and requiring oxygen therapy (severe group). Patient characteristics were compared between the two groups.We utilized univariate logistic regression analysis to confirm determinants of high risks of requiring oxygen therapy in patients with moderate COVID-19. ResultsThirty-five patients ware in severe group and forty-nine patients were in non-severe group. In comparison with patients in the non-severe group, patients in the severe group were significantly older with higher body mass index (BMI), and had a history of hypertension and diabetes. Serum blood urea nitrogen (BUN), lactic acid dehydrogenase (LDH), and C-reactive protein (CRP) levels were significantly higher in the severe group. Multivariate analysis showed that older age, higher BMI, and higher BUN levels were significantly associated with oxygen requirements. ConclusionsThis study demonstrated that age, BMI, and BUN were independent risk factors in the moderate-to-severe COVID-19 group. Elderly patients with higher BMI and BUN require close monitoring and early treatment initiation.

BTK inhibitors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): A systematic review

IntroductionThe Bruton tyrosine kinase (BTK) regulates B cell and macrophage signaling, development, survival, and activation. Inhibiting BTK has been hypothesized to ameliorate lung injury in patients with severe COVID-19, however clinical outcome data is inconclusive. ObjectiveTo evaluate the clinical outcomes of BTK inhibitors (BTKinibs) in patients with COVID-19. Evidence reviewWe searched PubMed, Embase, and Web of Science:Core on December 30, 2020. Clinical studies with at least 5 COVID-19 patients treated with BTKinibs were included. Case reports and reviews were excluded. Findings125 articles were identified, 6 of which met inclusion criteria. The most common clinical outcomes measured were oxygen requirements (4/6) and hospitalization rate or duration (3/6). Three studies showed decreased oxygen requirements in patients who started or continued BTKinibs. All three studies that evaluated hospitalization rate or duration found favorable outcomes in those on BTKinibs. Conclusions and relevanceBTKinib use was associated with decreased oxygen requirements and decreased hospitalization rates and duration.

2-DG as an adjunctive treatment in covid-19

Background: COVID-19, the pandemic in recent years which had a global detrimental effect over the mankind and healthcare system. There is no specific treatment for as of now. Antivirals, antibiotics. Steroids and multiple pharmaceutical strategies were tried in treatment of COVID-19.As per the clinical trials, viral infected cells and glucose metabolism were targeted for the treatment of COVID-19 with 2-Deoxy D glucose. 2-DG has been given the Emergency Use Autherisation as an adjunctive therapy along with standard of care in hospitalized patients. It acts by inhibition of viral replication and by inhibition of cytokine release. Aim: To study the role of 2-DG as an adjunct to proposed standard of treatment in COVID-19 patients. Materials and Methods: It is a cross sectional observational study conducted at Kamineni Academy of Medical Sciences and Research Centre, Hyderabad. Results: We have observed that there is declined RR and early weaning of oxygen support in patient of COVID-19 with 2 Dg as an adjunctive modality. There was significant decrease in Oxygen support after administration of 2-DG. In the study among subjects who recovered mean day of administration of 2-DG drug was 6.00 ± 1.512 days and among subjects who expired was 7.33 ± 2.646. However there was no significant difference in Day of administration of first dose of 2-DG with respect to outcome. Conclusion: In this study we have observed significant benefits in mortality outcomes and oxygen requirements in patients receiving 2-DG along with standard care of management.

Convalescent plasma for COVID-19 - encouraging signals of efficacy.

Convalescent plasma for COVID-19 - encouraging signals of efficacy.

Spontaneous bilateral pectoralis major hematoma secondary to therapeutic dose of enoxaparin in elderly Covid-19 patient

Type 1 respiratory failure secondary to ventilation-perfusion mismatch by micro-thrombus in the pulmonary vasculature and subsequent damage to the endothelial cells is by far the most typical presentation of Covid-19 pneumonia. Computed tomography pulmonary angiogram remains the investigation of choice to diagnose pulmonary embolism or micro-thrombi; however, it is not possible due to extreme hemodynamic instability or oxygen requirements in patients, making the transfer to the scanner a precarious affair. Therefore, clinicians worldwide use anticoagulant treatment doses based on clinical features, blood investigations, or echocardiography following local or national guidelines. In this report, we describe a case of bilateral pectoralis major hematoma due to treatment dose of enoxaparin in an elderly Covid-19 patient admitted in our ICU. This case report emphasises the need for extra precaution and vigilance while using treatment dose of anticoagulants for suspected pulmonary embolism in Covid-19 patients.

Prediction of an increase in oxygen requirement of SARS-CoV-2 pneumonia using three different scoring systems

IntroductionIn patients with severe coronavirus disease 2019 (COVID-19), respiratory failure is a major complication and its symptoms occur around one week after onset. The CURB-65, A-DROP and expanded CURB-65 tools are known to predict the risk of mortality in patients with community-acquired pneumonia. In this retrospective single-center retrospective study, we aimed to assess the correlations of the A-DROP, CURB-65, and expanded CURB-65 scores on admission with an increase in oxygen requirement in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia. MethodsWe retrospectively analyzed 207 patients who were hospitalized with SARS-CoV-2 pneumonia at the Self-Defense Forces Central Hospital in Tokyo, Japan. Performance of A-DROP, CURB-65, and the expanded CURB-65 scores were validated. In addition, we assessed whether there were any associations between an increase in oxygen requirement and known risk factors for critical illness in COVID-19, including elevation of liver enzymes and C-reactive protein (CRP), lymphocytopenia, high D-dimer levels and the chest computed tomography (CT) score. ResultsThe areas under the curve for the ability of CURB-65, A-DROP, and the expanded CURB-65 scores to predict an increase in oxygen requirement were 0.6961, 0.6980 and 0.8327, respectively, and the differences between the three groups were statistically significant (p < 0.001). Comorbid cardiovascular disease, lymphocytopenia, elevated CRP, liver enzyme and D-dimer levels, and higher chest CT score were significantly associated with an increase in oxygen requirement ConclusionsThe expanded CURB-65 score can be a better predictor of an increase in oxygen requirement in patients with SARS-CoV-2 pneumonia.

Association between peripheral blood/bronchoalveolar lavage eosinophilia and significant oxygen requirements in patients with acute eosinophilic pneumonia

BackgroundWe investigated the association between a combination of two markers, peripheral (PEC) and bronchoalveolar lavage (BAL) eosinophil percentage (BEP), and oxygen requirements in patients with acute eosinophilic pneumonia (AEP).MethodsWe retrospectively reviewed the medical records of patients with AEP treated at the Armed Forces Capital Hospital between May 2012 and May 2017. We used correlation analyses to assess the association between PEC/BEP and clinical outcomes in AEP patients. Receiver operating characteristic (ROC) curve analyses were used to calculate the cut-off value for BEP that categorised patients requiring a significant oxygen supply. The BAL/blood eosinophil (BBE) score was introduced to stratify patients with peripheral eosinophilia and elevated BEP. Clinical characteristics and outcomes were compared between the different groups. Multiple logistic regression was performed for significant oxygen requirements using two different models using age, C-reactive protein (CRP), smoking duration, and BBE score (model 1) and age, CRP, BEP, and PEC (model 2).ResultsAmong the 338 patients, 99.7% were male, and their mean age was 20.4 ± 1.4 years. Only 0.6% of patients were never smokers and the mean number of smoking days was 26.2 ± 25.4. Correlation analyses revealed that both the PaO2/FiO2 ratio and duration of oxygen supply were associated with BEP. ROC curve analyses indicated a cut-off level of 41.5%. Patients with a high BBE score had favourable outcomes in terms of hypoxemia, hospital days, intensive care unit admission, oxygen supply days, and steroid treatment days. Multiple logistic regression revealed that BEP and BBE score tended to be associated with significant oxygen requirements.ConclusionsIn this study, we revealed that both peripheral and BAL eosinophilia is associated with favourable outcomes in AEP patients.

Determining Prognosis in Neonates with Transient Tachypnea by Using Retraction Scores

Aim: The aim of this study is to evaluate the accuracy of physical and laboratory findings to determine the length of hospital stay and oxygen requirement in patients diagnosed with transient tachypnea of the newborn. Materials and Methods : Patients with respiratory distress symptoms that last more than 24 hours were admitted to the study. Sixty infants were analysed at the fourth hour and then daily in respect to their retraction scores, respiratory rates, urine outputs, blood gas measurements, and length of hospital stay. Infants were grouped into four categories according to their retraction scores and treatment modalities. Results: In the multiple regression analysis, the retraction scores and base excesses on the first day together with the urine output of the second-day were found to explain the 73% of the variance in the length of hospital stay and 68,7% of the variance in the oxygen requirement. The most important factor was found to be the retraction score of the first day. Boys were found to have five times higher risk than girls for severe transient tachypnea (OR: 5,06 %95 CI: 1,1-23,3, p: 0,037). Cesarean section, prematurity, and birth weight were not found to be risk factors for severe respiratory insufficiency. Conclusion: The present study proposes that clinicians may use the retraction scores to predict the length of hospital stay and oxygen requirements in neonates with transient tachypnea. The increase in urine output may be a sign of recovery. Male infants have five times higher risk of severe respiratory insufficiency due to transient tachypnea. Key Words: Blood Gas Analysis; Neonatology; Neonatal Intensive Care; Respiratory Insufficiency; Transient Tachypnea of The Newborn.

S68 The Hi-flo Study: A Prospective Open Randomised Controlled Trial Of High Flow Nasal Cannula Oxygen Therapy Against Standard Care In Bronchiolitis

Introduction High flow nasal cannula (HFNC) oxygen therapy is increasingly used as a form of respiratory support with limited evidence to support its use. Data from retrospective studies suggest that HFNC reduces rates of intubation and respiratory parameters in infants with bronchiolitis. It is well-tolerated, easy to use, and has very few adverse effects. Objective To determine if HFNC therapy reduces work of breathing, oxygen requirement and time to resolution of respiratory distress more quickly than standard care in bronchiolitis. Methods We conducted a prospective open randomised controlled trial to compare HFNC oxygen therapy with standard care for children with bronchiolitis in ward environments in a tertiary referral children’s hospital over a two-year study period. Patients under 18 months of age with a clinical diagnosis of bronchiolitis were eligible. Subjects were randomised to standard supportive care with low flow oxygen (up to 2 litres/minute) or HFNC oxygen at 8 litres/minute. Fractional inspired concentration of oxygen was titrated to maintain saturations >92%. A validated composite clinical score (modified Tal) was measured every 3 h. 1 Results 72 patients were recruited, 36 in each treatment arm. The mean age of subjects was 4 months, range 0.5–12.9 months. 42% were male, and all but two were born at term. 79% were RSV positive. 3 patients in the control group, and 4 in the intervention group required admission to intensive care. There was no improvement in time to resolution of respiratory distress or oxygen requirement in patients receiving HFNC oxygen therapy. There was a trend towards lower clinical scores in the first 3 h following initiation of treatment in the intervention group. There were no adverse effects from HFNC therapy, and it was found to be safe in a ward environment. Conclusion HFNC oxygen therapy may improve clinical parameters during the first hours of treatment, but it did not significantly reduce time to resolution of respiratory distress or oxygen requirement. Reference McCallum G, et al . Severity scoring systems: are they internally valid, reliable and predictive of oxygen use in children with acute bronchiolitis? Pediatric Pulmonology 2013;48(8):797–803

High Intraoperative Inspired Oxygen Does Not Increase Postoperative Supplemental Oxygen Requirements

Although a high fraction of inspired oxygen (FIO2) could reduce surgical site infection, there is concern it could increase postoperative pulmonary complications, including hypoxemia. Intraoperative positive end-expiratory pressure can improve postoperative pulmonary function. A practical measure of postoperative pulmonary function and the degree of hypoxemia is supplemental oxygen requirement. We performed a double-blind randomized 2 × 2 factorial study on the effects of intraoperative FIO2 0.3 versus more than 0.9 with and without positive end-expiratory pressure on the primary outcome of postoperative supplemental oxygen requirements in patients undergoing lower risk surgery. After Institutional Review Board approval and consent, 100 subjects were randomized using computer-generated lists into four treatment groups (intraoperative FIO2 0.3 vs. more than 0.9, with and without 3-5 cm H2O positive end-expiratory pressure). Thirty minutes and 24 h after extubation, supplemental oxygen was discontinued. Arterial oxygen saturation by pulse oximetry was recorded 15 min later. If oxygen saturation decreased to less than 90%, supplemental oxygen was added incrementally to maintain saturation more than 90%. Nearly all subjects required supplemental oxygen in the postanesthesia care unit. Nonparametric Wilcoxon rank sum test demonstrated no statistically significant difference between groups in supplemental oxygen requirements at 45 min and 24 h after tracheal extubation (P = 0.56 and 0.98, respectively). Use of intraoperative FIO2 more than 0.9 was not associated with increased oxygen requirement, suggesting it does not induce postoperative hypoxemia beyond anesthetic induction and surgery. Therefore, it may be reasonable to use high inspired oxygen in surgical patients with relatively normal pulmonary function.

Maximal oxygen uptake and severity of disease in lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM), a disease that occurs primarily in women, is characterized by cystic lung lesions causing respiratory failure, which may require lung transplantation. Lung diffusion (DLCO) and/or FEV1 are decreased, but frequently not in parallel with each other. Because cardiopulmonary exercise testing (CPET) provides information that is not obtainable from resting cardiopulmonary tests, we performed CPET in 217 LAM patients and correlated exercise data with clinical markers of severity, computed tomography scans, lung function, and histology. VO2max was decreased in 162 patients, of whom 28 did not reach anaerobic threshold; 29 had low oxygen uptake at anaerobic threshold, and 54 developed hypoxemia. Hypoxemia occurred even in patients with near normal DLCO and FEV1. VO2max decreased with an increasing score of histologic LAM severity and was correlated with computed tomography scans, the use of oxygen, and resting PaO2. DLCO and FEV1, however, were the only significant predictors of VO2max. We conclude that CPET uncovers the presence of exercise-induced hypoxemia and assists in grading the severity of disease and determining supplemental oxygen requirements in patients with LAM.

Con: Surgery is not the preferred treatment for acute myocardial infarction

N OT SINCE THE clinical description of acute myocardial infarction by Herrick in 19 12’ have there been so many options available for the treatment of this problem. Despite these options, acute myocardial infarction remains the most common cause of death in industrialized countries, and mortality and morbidity rates among the survivors of infarction are unacceptably high. It has been very interesting to watch the attempts to reduce this mortality. In the 196Os, defibrillation and the development of coronary care units resulted in a significant improvement in mortality. In the 197Os, research in ischemic heart disease was dominated by an attempt to reduce myocardial oxygen demand in an attempt to reduce the extent of infarction. Despite impressive results in experimental models showing myocardial salvage, it became clear that reduction of myocardial oxygen requirements in patients delayed the evolution of infarction but did not limit overall extent. However, these studies did show conclusively that prognosis-early and late-is influenced primarily by the size of the infarct. Limiting the size of the initial infarct continues to be the primary goal in the 1990s. The purpose of this review is to debate the best way of salvaging ischemic but not necrotic myocardium. It is agreed that reperfusion is the most effective way to limit infarct size. It is also agreed that if significant salvage is to occur the time interval between the onset of coronary occlusion and reperfusion must be brief. In the experimental setting, this time interval is usually not more than 4 to 6 hours.’ Accordingly, any reperfusion strategy designed to limit infarct size, if it is to be widely applicable to patients with acute myocardial infarction, must be applied soon after the development of symptoms.