scholarly journals Predicting the Need for Supplemental Oxygen During Airline Flight in Patients with Chronic Pulmonary Disease: A Comparison of Predictive Equations and Altitude Simulation

2009 ◽  
Vol 16 (4) ◽  
pp. 119-124 ◽  
Author(s):  
Ana C Bradi ◽  
Marie E Faughnan ◽  
Matthew B Stanbrook ◽  
Eva Deschenes-Leek ◽  
Kenneth R Chapman
Keyword(s):  
Predictive Value ◽  
Ground Level ◽  
Supplemental Oxygen ◽  
Forced Expiratory Volume ◽  
Arterial Oxygen ◽  
British Thoracic Society ◽  
Predictive Equations ◽  
Screening Guidelines ◽  
Specificity And Sensitivity ◽  
Increased Risk

BACKGROUND: Patients with chronic pulmonary diseases are at increased risk of hypoxemia when travelling by air. Screening guidelines, predictive equations based on ground level measurements and altitude simulation laboratory procedures have been recommended for determining risk but have not been rigorously evaluated and compared.OBJECTIVES: To determine the adequacy of screening recommendations that identify patients at risk of hypoxemia at altitude, to evaluate the specificity and sensitivity of published predictive equations, and to analyze other possible predictors of the need for in-flight oxygen.METHODS: The charts of 27 consecutive eligible patients referred for hypoxia altitude simulation testing before flight were reviewed. Patients breathed a fraction of inspired oxygen of 0.15 for 20 min. This patient population was compared with the screening recommendations made by six official bodies and compared the partial pressure of arterial oxygen (PaO2) obtained during altitude simulation with the PaO2predicted by 16 published predictive equations.RESULTS: Of the 27 subjects, 25% to 33% who were predicted to maintain adequate oxygenation in flight by the British Thoracic Society, Aerospace Medical Association or American Thoracic Society guidelines became hypoxemic during altitude simulation. The 16 predictive equations were markedly inaccurate in predicting the PaO2measured during altitude simulation; only one had a positive predictive value of greater than 30%. Regression analysis identified PaO2at ground level (r=0.50; P=0.009), diffusion capacity (r=0.56; P=0.05) and per cent forced expiratory volume in 1 s (r=0.57; P=0.009) as having predictive value for hypoxia at altitude.CONCLUSIONS: Current screening recommendations for determining which patients require formal assessment of oxygen during flight are inadequate. Predictive equations based on sea level variables provide poor estimates of PaO2measured during altitude simulation.

scholarly journals Highs and lows of hyperoxia: physiological, performance, and clinical aspects

2018 ◽  
Vol 315 (1) ◽  
pp. R1-R27 ◽  
Author(s):  
Julien Vincent Brugniaux ◽  
Geoff B. Coombs ◽  
Otto F. Barak ◽  
Zeljko Dujic ◽  
Mypinder S. Sekhon ◽  
...  
Keyword(s):  
Carbon Monoxide Poisoning ◽  
Barometric Pressure ◽  
Supplemental Oxygen ◽  
Arterial Oxygen ◽  
Future Research ◽  
Clinical Aspects ◽  
Comprehensive Overview ◽  
Diverse Range ◽  
Arterial Oxygen Content ◽  
Increased Risk

Molecular oxygen (O2) is a vital element in human survival and plays a major role in a diverse range of biological and physiological processes. Although normobaric hyperoxia can increase arterial oxygen content ([Formula: see text]), it also causes vasoconstriction and hence reduces O2 delivery in various vascular beds, including the heart, skeletal muscle, and brain. Thus, a seemingly paradoxical situation exists in which the administration of oxygen may place tissues at increased risk of hypoxic stress. Nevertheless, with various degrees of effectiveness, and not without consequences, supplemental oxygen is used clinically in an attempt to correct tissue hypoxia (e.g., brain ischemia, traumatic brain injury, carbon monoxide poisoning, etc.) and chronic hypoxemia (e.g., severe COPD, etc.) and to help with wound healing, necrosis, or reperfusion injuries (e.g., compromised grafts). Hyperoxia has also been used liberally by athletes in a belief that it offers performance-enhancing benefits; such benefits also extend to hypoxemic patients both at rest and during rehabilitation. This review aims to provide a comprehensive overview of the effects of hyperoxia in humans from the “bench to bedside.” The first section will focus on the basic physiological principles of partial pressure of arterial O2, [Formula: see text], and barometric pressure and how these changes lead to variation in regional O2 delivery. This review provides an overview of the evidence for and against the use of hyperoxia as an aid to enhance physical performance. The final section addresses pathophysiological concepts, clinical studies, and implications for therapy. The potential of O2 toxicity and future research directions are also considered.

scholarly journals Determining a target SpO2 to maintain PaO2 within a physiological range

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0250740
Author(s):  
Jantine G. Röttgering ◽  
Angelique M. E. de Man ◽  
Thomas C. Schuurs ◽  
Evert-Jan Wils ◽  
Johannes M. Daniels ◽  
...  
Keyword(s):  
Supplemental Oxygen ◽  
Arterial Oxygen ◽  
Ongoing Debate ◽  
Peripheral Oxygen Saturation ◽  
Arterial Hypoxemia ◽  
Physiological Range ◽  
Increased Risk ◽  
Potential Risks ◽  
Oxygenation Status ◽  
Function Testing

Objective In the context of an ongoing debate on the potential risks of hypoxemia and hyperoxemia, it seems prudent to maintain the partial arterial oxygen pressure (PaO2) in a physiological range during administration of supplemental oxygen. The PaO2 and peripheral oxygen saturation (SpO2) are closely related and both are used to monitor oxygenation status. However, SpO2 values cannot be used as an exact substitute for PaO2. The aim of this study in acutely ill and stable patients was to determine at which SpO2 level PaO2 is more or less certain to be in the physiological range. Methods This is an observational study prospectively collecting data pairs of PaO2 and SpO2 values in patients admitted to the emergency room or intensive care unit (Prospective Inpatient Acutely ill cohort; PIA cohort). A second cohort of retrospective data of patients who underwent pulmonary function testing was also included (Retrospective Outpatient Pulmonary cohort; ROP cohort). Arterial hypoxemia was defined as PaO2 < 60 mmHg and hyperoxemia as PaO2 > 125 mmHg. The SpO2 cut-off values with the lowest risk of hypoxemia and hyperoxemia were determined as the 95th percentile of the observed SpO2 values corresponding with the observed hypoxemic and hyperoxemic PaO2 values. Results 220 data pairs were collected in the PIA cohort. 95% of hypoxemic PaO2 measurements occurred in patients with an SpO2 below 94%, and 95% of hyperoxemic PaO2 measurements occurred in patients with an SpO2 above 96%. Additionally in the 1379 data pairs of the ROP cohort, 95% of hypoxemic PaO2 measurements occurred in patients with an SpO2 below 93%. Conclusion The SpO2 level marking an increased risk of arterial hypoxemia is not substantially different in acutely ill versus stable patients. In acutely ill patients receiving supplemental oxygen an SpO2 target of 95% maximizes the likelihood of maintaining PaO2 in the physiological range.

scholarly journals P82 NUn score validation at a district general hospital

BJS Open ◽  
2021 ◽  
Vol 5 (Supplement_1) ◽  
Author(s):  
Jacob Rapier ◽  
Steven Hornby ◽  
Jacob Rapier
Keyword(s):  
Positive Predictive Value ◽  
Anastomotic Leak ◽  
Confidence Intervals ◽  
Predictive Value ◽  
External Validation ◽  
District General Hospital ◽  
Anastomotic Leaks ◽  
Upper Gi ◽  
Increased Risk ◽  
Operative Complications

Abstract Introduction The NUn score was created to try and predict the risk of anastomotic leak or major complications (using the Clavien- Dindo classification) from upper GI resections with an oesophageal anastomosis. A score of &gt; 10 was used to predict an increased risk. In this study we attempt validation. Methods A database of 101 patients was studied, who underwent an Oesophagectomy for cancer between March 2017 and 2020. 72 patients had complete Post-operative day 4 bloods, needed to calculate the score. These patients were then studied for post-operative complications. Results A total of 12 patients had a NUn score of &gt; 10 (16.67%). There was 1 death (1.37%) and 11 anastomotic leaks (15.28%). Of these the NUn score did not predict the death and predicted 8 of the 11 anastomotic leaks. From our data Conclusion From our analysis the NUNs score cannot be shown to be sensitive, specific or have useful positive predictive value. The average Nun score was not reliable, with confidence intervals crossing 10. There may be some merit in using the test for its negative predictive value, but further analysis into this is needed. The results of this audit are consistent with previous efforts at external validation.

scholarly journals Validation of the SavvyCheckTM Vaginal Yeast Test for Screening Pregnant Women for Vulvovaginal Candidosis: A Prospective, Cross-Sectional Study

2021 ◽  
Vol 7 (3) ◽  
pp. 233
Author(s):  
Philipp Foessleitner ◽  
Herbert Kiss ◽  
Julia Deinsberger ◽  
Julia Ott ◽  
Lorenz Zierhut ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Predictive Value ◽  
Point Of Care ◽  
Cross Sectional Study ◽  
Control Group ◽  
Gram Stain ◽  
Cross Sectional ◽  
Point Of Care Test ◽  
Increased Risk ◽  
Vulvovaginal Candidosis

Pregnant women have an increased risk of vulvovaginal candidosis. Recurrent candidosis is under debate as a contributor to preterm birth, and vertical transmission may cause diaper dermatitis and oral thrush in the newborn. Apart from cultural methods, the gold standard for diagnosing candidosis is Gram staining, which is time-consuming and requires laboratory facilities. The objective of this prospective study was to validate a point-of-care vaginal yeast detection assay (SavvyCheckÔ Vaginal Yeast Test) and to evaluate it in asymptomatic pregnant women. We enrolled 200 participants, 100 of whom had vulvovaginal candidosis according to Gram stain (study group) and 100 were healthy pregnant controls (control group). Of these, 22 participants (11%) had invalid test results. The point-of-care test of the remaining 85 and 93 study participants in the study and control groups, respectively, showed a sensitivity of 94.1%, specificity of 98.9%, positive predictive value of 90.3%, and negative predictive value of 99.4% when compared with Gram stain. In conclusion, we found a high correlation between the SavvyCheckÔ Vaginal Yeast Test and Gram-stained smears during pregnancy. This suggests a potential role of this point-of-care test as a screening tool for asymptomatic pregnant women in early gestation.

scholarly journals The Effect of Supplemental Oxygen on the Incidence of Hypoxaemia after Premedication in Patients Undergoing Cardiac Surgery

1997 ◽  
Vol 25 (4) ◽  
pp. 347-349 ◽  
Author(s):  
C. F. Royse ◽  
R. J. B. Tiernan ◽  
S. M. Portelli ◽  
S. Davies ◽  
R. Arblaster ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Arterial Oxygen Saturation ◽  
Supplemental Oxygen ◽  
Arterial Oxygen ◽  
Patient Demographics ◽  
Routine Administration ◽  
High Incidence ◽  
Patient Groups ◽  
To Receive ◽  
Elective Patients

Opiate premedication may cause significant respiratory depression, particularly when other sedative agents such as scopolamine or benzodiazepines are added. This can cause hypoxaemia with potential for worsening myocardial ischaemia in cardiac surgery patients. The aim of this study was to investigate the incidence of hypoxaemia (SpO2 <90%) in elective patients undergoing cardiac surgery and to assess the efficacy of supplemental oxygen in preventing it. One hundred elective patients without significant respiratory disease or cardiac failure, who received both an opiate and a sedative premedication, were prospectively randomized to receive either oxygen via a facemask at 4 l/min or no oxygen. Continuous arterial oxygen saturation was recorded using a pulse oximeter from the time of premedication until the patient arrived in theatre. An SpO2 <90% was recorded as a significant event and oxygen was administered to the patients. Six patients were excluded because of equipment failure or protocol violations. The patient groups were comparable with respect to patient demographics, premedication type and dose or the duration of monitoring. In patients receiving oxygen (n=48) there were no episodes of hypoxaemia (0%). In patients not receiving oxygen (n=46) there were 14 episodes of hypoxaemia (30%, P<0.0001). We conclude that there is a significantly high incidence of hypoxaemia in cardiac surgery patients following combined opiate and sedative premedication and that it can be reduced by the routine administration of supplemental oxygen.

scholarly journals Probe-based confocal laser endomicroscopy and Barrett's esophagus – just a scientific toy or significant improvement in diagnosis?

2021 ◽  
Author(s):  
Luka Vranić ◽  
Tin Nadarević ◽  
Davor Štimac
Keyword(s):  
Diagnostic Accuracy ◽  
Real Time ◽  
Barrett’S Esophagus ◽  
Predictive Value ◽  
Barrett's Esophagus ◽  
High Reliability ◽  
Confocal Laser Endomicroscopy ◽  
Confocal Laser ◽  
Imaging Method ◽  
Increased Risk

Background: Barrett’s esophagus (BE) requires surveillance to identify potential neoplasia at early stage. Standard surveillance regimen includes random four-quadrant biopsies by Seattle protocol. Main limitations of random biopsies are high risk of sampling error, difficulties in histology interpretation, common inadequate classification of pathohistological changes, increased risk of bleeding and time necessary to acquire the final diagnosis. Probe-based confocal laser endomicroscopy (pCLE) has emerged as a potential tool with an aim to overcome these obvious limitations. Summary: pCLE represents real-time microscopic imaging method that offers evaluation of epithelial and subepithelial structures with 1000-fold magnification. In theory, pCLE has potential to eliminate the need for biopsy in BE patient. The main advantages would be real-time diagnosis and decision making, greater diagnostic accuracy and to evaluate larger area compared to random biopsies. Clinical pCLE studies in esophagus show high diagnostic accuracy and its high negative predictive value offers high reliability and confidence to exclude dysplastic and neoplastic lesions. However, it still cannot replace histopathology due to lower positive predictive value and sensitivity. Key messages: Despite promising results, its role in routine use in patients with Barrett’s esophagus remains questionable primarily due to lack of well-organized double-blind randomized trials.

IMPORTANCE OF ANTIBODIES TO 21-HYDROXYLASE FOR THE DIAGNOSIS, DIFFERENTIAL DIAGNOSIS AND PROGNOSIS OF AUTOIMMUNE CHRONIC PRIMARY ADRENAL INSUFFICIENCY

2021 ◽  
Vol 100 (2) ◽  
pp. 78-86
Author(s):  
L.S. Sozaeva ◽  
◽  
N.V. Makazan ◽  
L.V. Nikankina ◽  
N.M. Malysheva ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Adrenal Insufficiency ◽  
Predictive Value ◽  
Primary Adrenal Insufficiency ◽  
Polyglandular Autoimmune Syndrome ◽  
Diagnosis And Prognosis ◽  
Specificity And Sensitivity ◽  
Enzymelinked Immunosorbent Assay

21-hydroxylase (21-OH) is the main antigen of the adrenal cortex, so the determination of antibodies (Ab) to 21-OH can help in the diagnosis and prognosis of chronic primary adrenal insufficiency (CPAI). Purpose of the study: evaluation of the relevance of Ab to 21-OH for the diagnosis and prediction of autoimmune CPAI. Materials and methods of research: the study consisted of three blocks: 1) assessment of the specificity and sensitivity, as well as the prognostic potential of Ab to 21-OH in patients with polyglandular autoimmune syndrome (APS) – individuals with APS type 1 with and without CPAI (n=106); 2) assessment of the dynamics of the level of Ab to 21-OH – patients with autoimmune CPAI were included (n=41); 3) assessment of the significance of Ab data for the differential diagnosis of various forms of CPAI, including patients with CPAI and APS type 1 exclusion (n=30). The study of Ab to 21-hydroxylase was performed using enzymelinked immunosorbent assay (BioVendor kits, Czech Republic). Results: statistically significant differences were obtained in the frequency of detection of Ab to 21-OH in patients with or without PCNI (p<0,001). The sensitivity of the method was 96%, specificity was 75%, a positive predictive value was 90%, and the negative predictive value was 89%. In 83% of patients, the level of Ab decreased with time (median size decreases – 20,4%/year). An inverse relationship was also found between the level of Ab and the duration of the course of CPAI (R=–0,460, p<0,001). In a group of 30 patients with CPAI and with exclusion of APS type 1, 21 were found to have Ab to 21-OH, only one of them had a monogenic non-autoimmune cause of CPAI (a mutation in the MC2R gene). Monogenic forms of CPAI were found in another 7 patients (mutations were found in the DAX1 and ABCD1 genes), among them an increase in Ab to 21-OH was not detected. Conclusion: determination of Ab to 21-OH is a specific and sensitive method for the diagnosis of autoimmune CPAI. An increase in Ab to 21-OH is a risk marker of autoimmune CPAI development.

Persistent airflow obstruction in inner-city children with asthma

2021 ◽  
Vol 42 (4) ◽  
pp. 310-316
Author(s):  
Kenny Y. Kwong ◽  
Yang Z. Lu ◽  
Emilio Jauregui ◽  
Lyne Scott
Keyword(s):  
Lung Function ◽  
Inner City ◽  
Airway Remodeling ◽  
Airflow Obstruction ◽  
Later Life ◽  
Forced Expiratory Volume ◽  
Initial Visit ◽  
Asthma Care ◽  
Increased Risk ◽  
Children With Asthma

Background: Airway remodeling has been shown to be persistent in patients with asthma despite treatment with controller medications. Patients with early airflow obstruction may continue to experience poor lung function despite treatment. Objectives: To determine whether early airflow obstruction in inner-city children with asthma persists despite guideline-based asthma care. Methods: In a retrospective study that used a cohort of inner-city children with asthma treated by using an asthma-specific disease management system, the patients were stratified into “low” or “high” lung function groups at the time of the initial visit (high, forced expiratory volume in the first second of expiration [FEV1] % predicted and FEV1/forced vital capacity [FVC] ≥ 80%; and low, FEV1% predicted and FEV1/FVC < 80%). These patients then received National Heart, Lung, and Blood Institute guideline‐based asthma treatment at regular follow-up intervals with spirometry performed at these visits as part of regular care. FEV1% predicted and FEV1/FVC were followed up for up to 10 years for both the high and low cohorts. Results: Over 10 years, the patients initially in the “high” group maintained FEV1% predicted and FEV1/FVC at values similar to the initial visit (94 to 96% and 87 to 89%, respectively), whereas those in the low group had only slight increases of FEV1% predicted and FEV1/FVC over the same time (77 to 82% and 78 to 82%, respectively). Low FEV1% predicted and FEV1/FVC at the time of the first visit was significantly associated with an increased risk of low values of these lung functions over the next 3‐5 years despite treatment. African American ethnicity and male gender were also associated with lower lung function over time. Conclusion: Early airflow obstruction in inner city children asthma is associated with poor lung function in later life despite guideline-based asthma care. Current asthma therapy may not affect pathways and leads to airway remodeling in children with asthma.

scholarly journals Association between clinical risk scores and mortality in atrial fibrillation: Systematic review and network meta-regression of 669,000 patients

2018 ◽  
Vol 27 (6) ◽  
pp. 633-644 ◽  
Author(s):  
Marco Proietti ◽  
Alessio Farcomeni ◽  
Giulio Francesco Romiti ◽  
Arianna Di Rocco ◽  
Filippo Placentino ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Predictive Ability ◽  
Risk Scores ◽  
Clinical Risk ◽  
Increased Risk ◽  
High Negative Predictive Value ◽  
Meta Regression

Aims Many clinical scores for risk stratification in patients with atrial fibrillation have been proposed, and some have been useful in predicting all-cause mortality. We aim to analyse the relationship between clinical risk score and all-cause death occurrence in atrial fibrillation patients. Methods We performed a systematic search in PubMed and Scopus from inception to 22 July 2017. We considered the following scores: ATRIA-Stroke, ATRIA-Bleeding, CHADS2, CHA2DS2-VASc, HAS-BLED, HATCH and ORBIT. Papers reporting data about scores and all-cause death rates were considered. Results Fifty studies and 71 scores groups were included in the analysis, with 669,217 patients. Data on ATRIA-Bleeding, CHADS2, CHA2DS2-VASc and HAS-BLED were available. All the scores were significantly associated with an increased risk for all-cause death. All the scores showed modest predictive ability at five years (c-indexes (95% confidence interval) CHADS2: 0.64 (0.63–0.65), CHA2DS2-VASc: 0.62 (0.61–0.64), HAS-BLED: 0.62 (0.58–0.66)). Network meta-regression found no significant differences in predictive ability. CHA2DS2-VASc score had consistently high negative predictive value (≥94%) at one, three and five years of follow-up; conversely it showed the highest probability of being the best performing score (63% at one year, 60% at three years, 68% at five years). Conclusion In atrial fibrillation patients, contemporary clinical risk scores are associated with an increased risk of all-cause death. Use of these scores for death prediction in atrial fibrillation patients could be considered as part of holistic clinical assessment. The CHA2DS2-VASc score had consistently high negative predictive value during follow-up and the highest probability of being the best performing clinical score.

Acute hypoxia in a simulated high-altitude airdrop scenario due to oxygen system failure

2017 ◽  
Vol 123 (6) ◽  
pp. 1443-1450 ◽  
Author(s):  
William Ottestad ◽  
Tor Are Hansen ◽  
Gaurav Pradhan ◽  
Jan Stepanek ◽  
Lars Øivind Høiseth ◽  
...  
Keyword(s):  
High Altitude ◽  
Acute Hypoxia ◽  
Supplemental Oxygen ◽  
Cerebral Oximetry ◽  
Arterial Oxygen ◽  
Hypoxic Exposure ◽  
System Failure ◽  
Oxygen System ◽  
Simulated High Altitude ◽  
Oxygen Tensions

High-Altitude High Opening (HAHO) is a military operational procedure in which parachute jumps are performed at high altitude requiring supplemental oxygen, putting personnel at risk of acute hypoxia in the event of oxygen equipment failure. This study was initiated by the Norwegian Army to evaluate potential outcomes during failure of oxygen supply, and to explore physiology during acute severe hypobaric hypoxia. A simulated HAHO without supplemental oxygen was carried out in a hypobaric chamber with decompression to 30,000 ft (9,144 m) and then recompression to ground level with a descent rate of 1,000 ft/min (305 m/min). Nine subjects were studied. Repeated arterial blood gas samples were drawn throughout the entire hypoxic exposure. Additionally, pulse oximetry, cerebral oximetry, and hemodynamic variables were monitored. Desaturation evolved rapidly and the arterial oxygen tensions are among the lowest ever reported in volunteers during acute hypoxia. PaO2 decreased from baseline 18.4 (17.3–19.1) kPa, 138.0 (133.5–143.3) mmHg, to a minimum value of 3.3 (2.9–3.7) kPa, 24.8 (21.6–27.8) mmHg, after 180 (60–210) s, [median (range)], N = 9. Hyperventilation with ensuing hypocapnia was associated with both increased arterial oxygen saturation and cerebral oximetry values, and potentially improved tolerance to severe hypoxia. One subject had a sharp drop in heart rate and cardiac index and lost consciousness 4 min into the hypoxic exposure. A simulated high-altitude airdrop scenario without supplemental oxygen results in extreme hypoxemia and may result in loss of consciousness in some individuals. NEW & NOTEWORTHY This is the first study to investigate physiology and clinical outcome of oxygen system failure in a simulated HAHO scenario. The acquired knowledge is of great value to make valid risk-benefit analyses during HAHO training or operations. The arterial oxygen tensions reported in this hypobaric chamber study are among the lowest ever reported during acute hypoxia.

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