Case Studies in Physiology: Untangling the cause of hypoxemia in a patient with obesity with acute leukemia

Amaza, Iliya; Kalra, Hardik; Eberlein, Michael; Jethava, Yogesh; McDonell, Joseph; Wolfe, Bobby; Tomasson, Michael H.; Bates, Melissa L.

doi:10.1152/japplphysiol.00867.2020

Cited by 4 publications

(3 citation statements)

References 23 publications

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“…Until now, reports of clinical application of the AGM100 remained anecdotal and confined to patients with acute respiratory failure [25,26], mainly due to the novelty of this method. To the best of our knowledge, this research represents the widest validation study of such non-invasive gas exchange assessment method in a homogenous cohort of hypoxemic patients with moderate-to-severe COPD, following a short high-altitude exposure.…”

Section: Discussionmentioning

confidence: 99%

Validation of Noninvasive Assessment of Pulmonary Gas Exchange in Patients with Chronic Obstructive Pulmonary Disease during Initial Exposure to High Altitude

Champigneulle

Reinhard²,

Mademilov

et al. 2023

JCM

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Investigation of pulmonary gas exchange efficacy usually requires arterial blood gas analysis (aBGA) to determine arterial partial pressure of oxygen (mPaO2) and compute the Riley alveolar-to-arterial oxygen difference (A-aDO2); that is a demanding and invasive procedure. A noninvasive approach (AGM100), allowing the calculation of PaO2 (cPaO2) derived from pulse oximetry (SpO2), has been developed, but this has not been validated in a large cohort of chronic obstructive pulmonary disease (COPD) patients. Our aim was to conduct a validation study of the AG100 in hypoxemic moderate-to-severe COPD. Concurrent measurements of cPaO2 (AGM100) and mPaO2 (EPOC, portable aBGA device) were performed in 131 moderate-to-severe COPD patients (mean ±SD FEV1: 60 ± 10% of predicted value) and low-altitude residents, becoming hypoxemic (i.e., SpO2 < 94%) during a short stay at 3100 m (Too-Ashu, Kyrgyzstan). Agreements between cPaO2 (AGM100) and mPaO2 (EPOC) and between the O2-deficit (calculated as the difference between end-tidal pressure of O2 and cPaO2 by the AGM100) and Riley A-aDO2 were assessed. Mean bias (±SD) between cPaO2 and mPaO2 was 2.0 ± 4.6 mmHg (95% Confidence Interval (CI): 1.2 to 2.8 mmHg) with 95% limits of agreement (LoA): −7.1 to 11.1 mmHg. In multivariable analysis, larger body mass index (p = 0.046), an increase in SpO2 (p < 0.001), and an increase in PaCO2-PETCO2 difference (p < 0.001) were associated with imprecision (i.e., the discrepancy between cPaO2 and mPaO2). The positive predictive value of cPaO2 to detect severe hypoxemia (i.e., PaO2 ≤ 55 mmHg) was 0.94 (95% CI: 0.87 to 0.98) with a positive likelihood ratio of 3.77 (95% CI: 1.71 to 8.33). The mean bias between O2-deficit and A-aDO2 was 6.2 ± 5.5 mmHg (95% CI: 5.3 to 7.2 mmHg; 95%LoA: −4.5 to 17.0 mmHg). AGM100 provided an accurate estimate of PaO2 in hypoxemic patients with COPD, but the precision for individual values was modest. This device is promising for noninvasive assessment of pulmonary gas exchange efficacy in COPD patients.

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Section: Discussionmentioning

confidence: 99%

Validation of Noninvasive Assessment of Pulmonary Gas Exchange in Patients with Chronic Obstructive Pulmonary Disease during Initial Exposure to High Altitude

Champigneulle

Reinhard²,

Mademilov

et al. 2023

JCM

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“…A recent case report highlighted the use of the non-invasive approach in determining the underlying cause of a gas exchange defects in a patient in whom ABGs could not readily be obtained ( Amaza et al, 2021 ). This report served to highlight the potential of the non-invasive approach, and further showed that the approach was useful as a teaching tool.…”

Section: Oxygen Deficit In Patients With Lung Diseasementioning

confidence: 99%

Non-invasive Measurement of Pulmonary Gas Exchange Efficiency: The Oxygen Deficit

Prisk

West

2021

Front. Physiol.

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The efficiency of pulmonary gas exchange has long been assessed using the alveolar-arterial difference in PO2, the A-aDO2, a construct developed by Richard Riley ~70years ago. However, this measurement is invasive (requiring an arterial blood sample), time consuming, expensive, uncomfortable for the patients, and as such not ideal for serial measurements. Recent advances in the technology now provide for portable and rapidly responding measurement of the PO2 and PCO2 in expired gas, which combined with the well-established measurement of arterial oxygen saturation via pulse oximetry (SpO2) make practical a non-invasive surrogate measurement of the A-aDO2, the oxygen deficit. The oxygen deficit is the difference between the end-tidal PO2 and the calculated arterial PO2 derived from the SpO2 and taking into account the PCO2, also measured from end-tidal gas. The oxygen deficit shares the underlying basis of the measurement of gas exchange efficiency that the A-aDO2 uses, and thus the two measurements are well-correlated (r2~0.72). Studies have shown that the new approach is sensitive and can detect the age-related decline in gas exchange efficiency associated with healthy aging. In patients with lung disease the oxygen deficit is greatly elevated compared to normal subjects. The portable and non-invasive nature of the approach suggests potential uses in first responders, in military applications, and in underserved areas. Further, the completely non-invasive and rapid nature of the measurement makes it ideally suited to serial measurements of acutely ill patients including those with COVID-19, allowing patients to be closely monitored if required.

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“…Previous cultural factors can be expected to influence how this group communicates with patients [11,14]. Many doctors undertaking the Royal Australian College of General Practice (RACGP) Practice Experience Program (PEP) obtained their primary qualifications overseas and are working in areas of workforce shortage under limited or no formal supervision [15]. PEP is a self-directed education program delivered in partnership with training organisations to support doctors gain RACGP Fellowship, thereby allowing them to continue to practice in Australia in the primary care sector as GP specialists.…”

Section: Introductionmentioning

confidence: 99%

A comparison of patient appraisal of professional skills for GPs in training participating in differing education programs

Narayanan

Vayro²,

Greco

et al. 2022

BMC Med Educ

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Background Medical boards and healthcare providers internationally are coming under increasing pressure to attract international medical graduates (IMGs) and overseas trained doctors (OTDs) to cope with predicted general practice (GP) doctor shortages. Various pathways to registration are made available for this purpose. There is very little understanding of the effects of different training pathways to licensing and registration on the ability of IMGs and OTDs, as well as locally trained doctors, to acquire the desirable professional skills deemed necessary for working effectively in the primary care sector. Methods Feedback from patients was collected at the end of their scheduled consultation with their doctor using a questionnaire consisting of 13 Likert scale items that asked them to rate their experience of the consultation. Feedback was obtained for doctors going through the Royal Australian College of General Practice (RACGP) Practice Experience Program (PEP) and the Australian General Practice Training Program (AGPT), with the former intended primarily for IMGs and OTDs, and the latter for local medical graduates including from New Zealand. Patient feedback was also obtained for patients visiting already Fellowed and experienced GPs for comparative purposes, resulting in data for three groups of doctors (two trainee, one already Fellowed). Rater consistency and agreement measures, analysis of variance, principal component analysis, t-tests and psychometric network analysis were undertaken between and within groups to identify similarities and differences in patient experience and professionalism of doctors. Results There was a small but significant difference in average patient raw scores given to PEP and AGPT doctors (90.25, 90.97%), with the highest scores for ‘Respect shown’ (92.24, 93.15%) and the lowest for ‘Reassurance’ 89.38, 89.84%). Male patients gave lower scores (89.56%) than female patients (91.23%) for both groups of doctors. In comparison, patients gave experienced GPs an average 91.38% score, with male patients giving a lower average score than female patients (90.62, 91.93%). Two components were found in the patient data (interpersonal communication, caring/empathy) that account for over 80% of the variance. When patient scores were aggregated by doctor, the average PEP and AGPT doctor scores received were 90.27 and 90.99%, in comparison to the average experienced GP score of 91.43%. Network analysis revealed differences in the connectedness of items between these two groups as well as in comparison with experienced GPs, suggesting that PEP doctors’ skills are less cohesively developed in the areas of listening ability, explaining and providing reassurance. Conclusions The small but statistically significant differences between doctor groups reported in this preliminary study are supplemented by percentile analysis, network analysis and principal component analysis to identify areas for further exploration and study. There is scope for improving the integration of interpersonal communication skills of GPs in Training with their caring and empathy skills, when compared with experienced GPs as a benchmark. Suggestions are made for enhancing professional skills from a patients’ perspective in future training programs.

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Case Studies in Physiology: Untangling the cause of hypoxemia in a patient with obesity with acute leukemia

Cited by 4 publications

References 23 publications

Validation of Noninvasive Assessment of Pulmonary Gas Exchange in Patients with Chronic Obstructive Pulmonary Disease during Initial Exposure to High Altitude

Validation of Noninvasive Assessment of Pulmonary Gas Exchange in Patients with Chronic Obstructive Pulmonary Disease during Initial Exposure to High Altitude

Non-invasive Measurement of Pulmonary Gas Exchange Efficiency: The Oxygen Deficit

A comparison of patient appraisal of professional skills for GPs in training participating in differing education programs

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