From Science to Diagnosis

Trusted research partners demonstrate the importance of speed and accuracy of the MediPines AGM100.
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Oxygen Deficit®

Key measure of blood oxygenation improves diagnostic information.

Research Highlight: Oxygen Deficit

How you can use oxygen deficit as the first and primary measure of pulmonary health.

The important clinical measurement of the A-aDO2 has been
performed using an invasive approach for ~70 years. The Oxygen Deficit directly addresses the efficiency of gas exchange.

The Oxygen Deficit (OD) comes from a direct measurement of expired gas partial pressures and uses a non-invasive means to determine what would otherwise be an invasive arterial blood gas. Obtaining the Oxygen Deficit requires only that the patient breathe quietly on a mouthpiece while wearing a nose-clip for ~2 min.

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Contents

Measuring Gas Exchange

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Measuring Gas Exchange

Assessing respiratory impairment in patients is a critical aspect of clinical management. Traditionally, the Riley method (A-a gradient) has been the gold standard measure for gas exchange efficiency, but this approach is invasive, expensive, and time-consuming, and as a result has limited use in acute clinical settings.  MediPines’ CEO, Steve Lee, collaborated with Dr. West to take the respiratory physiology concepts developed throughout his storied career (West, 2018) and translate it into an actual medical device that can be used at the bed side. The medical device that was created, the AGM100, gives clinicians fast, objective, and non-invasive respiratory metrics to help inform their respiratory assessment and clinical decision making.MediPines-Summary-of-West-Study-2018-published-in-Chest cover

With the development of MediPines Oxygen Deficit, gas exchange efficiency can now be measured non-invasively and quickly at the point of care.  What sets the AGM100 apart is the ability to get a non-invasive measurement of PaO2 and A-a gradient in less than 2 minutes. Additionally, our gas exchange analyzer provides other useful metrics (i.e., ETCO2 and P/F Ratio) health care workers are not used to having readily available at their fingertips.

  • O₂ Deficit is a non-invasive measure of the degree of respiratory impairment. It measures how well oxygen is being transported from the alveoli to the arterial capillary blood in the lung.

Respiratory Parameters

  • O₂ Deficit
  • gPaO₂™
  • gPaO₂ / PAO₂
  • gPaO₂ / FiO₂
  • PAO₂
  • PETCO₂
  • Pleth
  • RQ
  • PIO₂
  • RQ
  • SpO₂
  • RR

Relevant Publications

  1. A lifetime of pulmonary gas exchange. West, J.B. Physiological Reports. 2018 Oct;6(20):e13903. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6198137/
  2. Prisk GK & West JB (2021). Non-invasive Measurement of Pulmonary Gas Exchange Efficiency: The Oxygen Deficit. Front Physiol; DOI: 10.3389/fphys.2021.757857. https://pubmed.ncbi.nlm.nih.gov/34744795/
  3. West JB, Wang DL, Prisk GK, Fine JM, Bellinghausen A, Light M & Crouch DR (2019). Noninvasive measurement of pulmonary gas exchange: Comparison with data from arterial blood gases. Am J Physiol - Lung Cell Mol Physiol 316, L114–L118. https://pubmed.ncbi.nlm.nih.gov/30335497/
  4. West JB, Liu MA, Stark PC & Kim Prisk G (2020). Measuring the efficiency of pulmonary gas exchange using expired gas instead of arterial blood: comparing the “ideal” PO2 of Riley with end-tidal PO2. Am J Physiol - Lung Cell Mol Physiol 319, L289–L293. https://pubmed.ncbi.nlm.nih.gov/32491950/
  5. Go West: translational physiology for noninvasive measurement of pulmonary gas exchange in patients with hypoxemic lung disease. Pickerodt P.A., & Kuebler W.M. American Journal of Physiology, Lung Cellular and Molecular Physiology. 2019 Mar 6;316: L701–L702. https://www.ncbi.nlm.nih.gov/pubmed/30838868
  6. A New, Noninvasive Method of Measuring Impaired Pulmonary Gas Exchange in Lung Disease: An Outpatient Study. West J.B., Crouch D.R., Fine J.M., Makadia D., Wang D.L., Prisk G.K. CHEST. 2018;154(2), pp. 363-369. https://www.ncbi.nlm.nih.gov/pubmed/29452100
  7. Measurements of pulmonary gas exchange efficiency using expired gas and oximetry: results in normal subjects. West, J.B., Wang, D.L., Prisk D.K. American Journal of Physiology-Lung Cellular Molecular Physiology. 2018 Apr 1;314(4): L686-L689. https://www.ncbi.nlm.nih.gov/pubmed/29351442

Clinical Accuracy

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Physiological Science Drives Clinical Validation

Clinicians know that unlike other tests, the AGM100 provides accurate measurements of gas exchange impairment in healthy and sick patients.  This is by design.   Published studies have demonstrated the validity of O2 deficit in standard patient care, with exercise, and under conditions of extreme pressure. MediPines-Summary-of-Ainslie-Study-as-Published-in-CHEST-cover 

The AGM100 delivers a valid and reliable measure against directly measured arterial blood gasses at rest and during hypoxic exercise. Further, the non-invasive oxygen deficit was strongly correlated with A-aDO2 values obtained from the classic invasive approach. These results provide promising evidence to support the use of non-invasive gas exchange assessments which may be applicable to both laboratory and clinical patient assessments.  Under combined conditions of normoxic rest, hypoxic rest and hypoxic exercise, the results revealed strong correlations between the calculated gPaO2  and directly measured PaO2 (arterial blood gas).

The oxygen deficit includes contributions from lung units with both abnormally low and abnormally high ventilation-perfusion ratios.
The new method has the great advantage that an arterial blood sample is not required.

Relevant Publications

  1. West JB, Wang DL, Prisk GK, Fine JM, Bellinghausen A, Light M & Crouch DR (2019). Noninvasive measurement of pulmonary gas exchange: Comparison with data from arterial blood gases. Am J Physiol - Lung Cell Mol Physiol 316, L114–L118. https://pubmed.ncbi.nlm.nih.gov/30335497/
  2. West JB, Liu MA, Stark PC & Kim Prisk G (2020). Measuring the efficiency of pulmonary gas exchange using expired gas instead of arterial blood: comparing the “ideal” PO2 of Riley with end-tidal PO2. Am J Physiol - Lung Cell Mol Physiol 319, L289–L293. https://pubmed.ncbi.nlm.nih.gov/32491950/
  3. Noninvasive measurement of pulmonary gas exchange: comparison with data from arterial blood gases. West, J. B., Wang, D. L., Prisk, G. K., Fine, J. M., Bellinghausen, A., Light, M. P., & Crouch, D. R. American Journal of Physiology-Lung Cellular and Molecular Physiology. 2018. https://www.ncbi.nlm.nih.gov/pubmed/30335497
  4. Liu MA, Stark PC, Kim Prisk G & West JB (2020). Oxygen deficit is a sensitive measure of mild gas exchange impairment at inspired O2 between 12.5% and 21%. Am J Physiol - Lung Cell Mol Physiol 319, L91–L94. https://pubmed.ncbi.nlm.nih.gov/32401675/
  5. Howe CA, MacLeod DB, Wainman L, Oliver SJ & Ainslie PN (2020). Validation of a Noninvasive Assessment of Pulmonary Gas Exchange During Exercise in Hypoxia. Chest 158, 1644–1650. https://pubmed.ncbi.nlm.nih.gov/32343965/
  6. Manella, G., Ezagouri, S., Champigneulle, B., Gaucher, J., Mendelson, M., Lemarie, E., Stauffer, E., Pichon, A., Howe, C. A., Doutreleau, S., Golik, M., Verges, S., & Asher, G. (2022). The human blood transcriptome exhibits time-of-day-dependent response to hypoxia: Lessons from the highest city in the world. Cell Reports, 40(7). https://doi.org/10.1016/j.celrep.2022.111213
  7. Patrician A, Gasho C, Spajić B, Caldwell HG, Baković-Kramaric D, Barak O, Drviš I, Dujić Ž & Ainslie PN (2021). Case studies in physiology: Breath-hold diving beyond 100 meters—cardiopulmonary responses in world-champion divers. J Appl Physiol 130, 1345–1350. https://pubmed.ncbi.nlm.nih.gov/33600279/

 

Operational Efficiency

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Differential Diagnosis

Improving Outcomes for Hypoxemia and COVID-19

Hypoxemia

Patients in respiratory distress require immediate medical attention. The ability to quickly identify hypoxemia, a common respiratory symptom, and its cause is crucial for positive patient outcomes. However, there is a gap in the current cardiopulmonary assessment toolkit that leaves clinicians unable to quickly identify the cause and severity of hypoxemia. This assessment gap creates costly time delays in diagnosis and treatment decisions, which can have serious consequences for care path decisions and patient outcomes. This often manifests as overcrowded emergency rooms, overworked medical staff, and ineffective utilization of healthcare resources.

Hypoxemia, or low blood oxygen, is a common symptom that can quickly develop into a life-threatening situation unless it is properly detected at the first signs of danger.  Traditionally, multiple tests are available to narrow the differential diagnoses of respiratory conditions. Typically, each test eliminates or confirms a potential diagnosis, creating an approach that involves a process of elimination that delays diagnosis and treatment. 

The video below highlights how an emergency room used the AGM100 to quickly triage COVID patients.

ER visits respiratory

 

Relevant Publications

  1. Sieck D, Ozon P (2021). Use of a Non-Invasive Pulmonary Gas-Exchange Analyzer to Improve the Pretest Probability of Pulmonary Embolism in a Patient Classified as “Low Risk”. Am J Respir Care Med 2021; 203: A2385 https://www.atsjournals.org/doi/pdf/10.1164/ajrccm-conference.2021.203.1_MeetingAbstracts.A2385
  2. McGuire WC, Pearce AK, Elliott AR, Fine J, West JB, Prisk G, Crouch DR, Malhotra A (2022). Use of the Alveolar Gas Meter to Predict Respiratory Deterioration in COVID-19. Am J Respir Care Med 2022; 205: A4279. https://www.atsjournals.org/doi/pdf/10.1164/ajrccm-conference.2022.205.1_MeetingAbstracts.A4279
  3. MedScape video with Dr. Cameron
  4. Beyond Pulse Oximetry to Pulmonary Has Exchange Measurement in COVID-19 (2020). MediPines Scientific Series

 

Operational Efficiency

carepathway

What You Need to Know

  1. Beyond Pulse Oximetry to Pulmonary Has Exchange Measurement in COVID-19 (2020). MediPines Scientific Series https://www.medipines.com/wp-content/uploads/2021/04/MP-July-2020-Beyond-Pulse-Oximetry-to-Pulmonary-Gas-Exchange-Measurement-in-COVID-19-71320.pdf
  2. Hypoxemia white paper

Select Publications

Go West: translational physiology for noninvasive measurement of pulmonary gas exchange in patients with hypoxemic lung disease. Pickerodt P.A., & Kuebler W.M. American Journal of Physiology, Lung Cellular and Molecular Physiology. 2019 Mar 6;316: L701–L702. https://www.ncbi.nlm.nih.gov/pubmed/30838868

A New, Noninvasive Method of Measuring Impaired Pulmonary Gas Exchange in Lung Disease: An Outpatient Study. West J.B., Crouch D.R., Fine J.M., Makadia D., Wang D.L., Prisk G.K. CHEST. 2018;154(2), pp. 363-369. https://www.ncbi.nlm.nih.gov/pubmed/29452100

Measurements of pulmonary gas exchange efficiency using expired gas and oximetry: results in normal subjects. West, J.B., Wang, D.L., Prisk D.K. American Journal of Physiology-Lung Cellular Molecular Physiology. 2018 Apr 1;314(4): L686-L689. https://www.ncbi.nlm.nih.gov/pubmed/29351442

Noninvasive measurement of pulmonary gas exchange: comparison with data from arterial blood gases. West, J. B., Wang, D. L., Prisk, G. K., Fine, J. M., Bellinghausen, A., Light, M. P., & Crouch, D. R. American Journal of Physiology-Lung Cellular and Molecular Physiology. 2018. https://www.ncbi.nlm.nih.gov/pubmed/30335497

A lifetime of pulmonary gas exchange. West, J.B. Physiological Reports. 2018 Oct;6(20):e13903. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6198137/

Measuring the efficiency of pulmonary gas exchange using expired gas instead of arterial blood: comparing the “ideal” Po2 of Riley with end-tidal Po2. West JB, Liu MA, Stark PC, Prisk GK. American Journal of Physiology-Lung Cellular and Molecular Physiology 2020;319(2):L289-L293. https://journals.physiology.org/doi/full/10.1152/ajplung.00150.2020

Validation of a Non-invasive Assessment of Pulmonary Gas Exchange During Exercise in Hypoxia. Ainslie, Philip N., Howe, Connor A., MacLeod, David B., Wainman, Liisa, Oliver, Samuel J., CHEST. 2020 Apr. https://www.ncbi.nlm.nih.gov/pubmed/32343965