Alveolar vs Respiratory Notes

A-a oxygen gradient — The alveolar - arterial (A-a) oxygen gradient is a measure of oxygen transfer across alveolar capillary membrane (“A” denotes alveolar and “a” denotes arterial oxygenation). It is the difference between the amount of the oxygen in the alveoli. PAO2 = Alveolar oxygen tension PaO2 = Arterial oxygen tension A-a oxygen gradient = PAO2 - PaO2. PaO2 is derived from ABG while PAO2 is calculated. PAO2 = (FiO2 x [Patm - PH2O]) - (PaCO2 ÷ R) FiO2 is the fraction of inspired oxygen (0.21 at room air). Patm is the atmospheric pressure (760 mmHg at sea level). PH2O is the partial pressure of water (47 mmHg ). PaCO2 is derived from ABG , and R is the respiratory quotient. (The respiratory quotient is approximately 0.8 at normal physiological state) A-a gradient varies with age and can be estimated from the following equation, assuming the patient is breathing room air. A-a gradient = 2.5 + 0.21 x age in years A-a gradient increases with higher FiO2. PaO2/FiO2 ratio — The PaO2/FiO2 ratio is a measure of oxygen transfer across the alveolar capillary membrane . Normal PaO2/FiO2 ratio is 300 to 500 mmHg, with values less than 300 mmHg indicating impaired gas exchange and values less than 200 mmHg indicates severe hypoxemia . Concept By: Dr. Satish Deopujari Dr Vivek Shivhare Disclaimer: This app is based on equations available publicly in Medical domain.  The information contained on this app is intended for educational purposes only. It does not constitute medical advice. You should consult a physician regarding medical diagnosis or treatment.

"Try before you buy"" - Download the FREE App, which includes sample content. An in-App purchase is required to unlock all content.   Procedure-based format, all the respiratory therapy information you need at your fingertips. Respiratory Notes: Respiratory Therapist's Pocket Guide a quick-reference tool that put all the respiratory therapy information you need at your fingertips. The procedure-based format includes supporting illustrations, fill-in-the-blank forms, and algorithms to help you study and guide you in practice. Key Features * Bullet-point reviews guide you through procedures. * Quick-scan illustrations and tables summarize data. * Algorithms are based on AARC Clinical Practice Guidelines. * Key forms allow you to gather data at the bedside, and then transcribe to conventional charts New to this Edition * NEW! Pulmonary Disease and Airway/Ventilation Tabs * NEW! Comprehensive index * UPDATED! Procedures now organized around protocols No internet connection is required to access the content after the initial download. Find information quickly using powerful SmartSearch technology. Search part of term for those hard to spell medical terms. Content licensed from printed ISBN 10: 0803629222 Content licensed from printed ISBN 13: 9780803629226 SUBSCRIPTION : Please choose an auto renewable subscription plan to receive content access & continuous updates. Your subscription automatically renews as per your plan, so you always have the latest content.   Yearly auto-renewing payments - $29.99   Payment will be charged to your iTunes Account at confirmation of purchase. Subscription automatically renews unless auto-renew is turned off at least 24-hours before the end of the current period. Subscription may be managed by the user & auto-renewal can be disabled at any time by going to your device “Settings” and tapping “iTunes & App Store”. Any unused portion of a free trial period will be forfeited when you purchase a subscription, where applicable.   If you have any questions or comments, email us any time: customersupport@skyscape.com or call 508-299-30000   Privacy Policy-https://www.skyscape.com/terms-of-service/privacypolicy.aspx Terms and Conditions-https://www.skyscape.com/terms-of-service/licenseagreement.aspx   Editor(s):  Gary C. White MEd RRT RPFT Publisher: F. A. Davis Company