P:F ratio: Difference between revisions
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In [[pulmonary medicine]] and [[anesthesiology]], the '''P:F ratio''' is the ratio of arterial oxygen concentration to the fraction of inspired oxygen. It reflects how well the lungs absorb oxygen from expired air. <ref>{{citation | |||
| journal = Medscape Medical News | |||
| contribution = P/F Ratio May Be a Marker of Potential Intraoperative Ventilator-Induced Lung Injury | |||
| title = Coverage of the American Society of Anesthesiologists (ASA) 2009 Annual Meeting | |||
| author = Caroline Helwick | |||
| url = http://www.medscape.com/viewarticle/711235}}</ref> | |||
:<math>{P/F\ ratio} = \left (\frac{PaO_2}{Fi0_2}\right) \times 100</math> | :<math>{P/F\ ratio} = \left (\frac{PaO_2}{Fi0_2}\right) \times 100</math> | ||
An example in a healthy person: | An example in a healthy person: | ||
| Line 5: | Line 12: | ||
A higher ratio indicates better gas exchange: | A higher ratio indicates better gas exchange: | ||
* Normal is 500 | * Normal is 500 | ||
* [[ | * [[Acute respiratory distress syndrome|ARDS]] is < 200 | ||
Comparative studies suggest this measure correlates better with pulmonary shunts than does the A-a gradient.<ref name="pmid6409506">{{cite journal |author=Covelli HD, Nessan VJ, Tuttle WK |title=Oxygen derived variables in acute respiratory failure |journal=Crit. Care Med. |volume=11 |issue=8 |pages=646–9 |year=1983 |pmid=6409506 |doi=}}</ref><ref name="pmid14769743">{{cite journal |author=El-Khatib MF, Jamaleddine GW |title=A new oxygenation index for reflecting intrapulmonary shunting in patients undergoing open-heart surgery |journal=Chest |volume=125 |issue=2 |pages=592–6 |year=2004 |pmid=14769743 |doi=}}</ref><ref name="pmid3191742">{{cite journal |author=Cane RD, Shapiro BA, Templin R, Walther K |title=Unreliability of oxygen tension-based indices in reflecting intrapulmonary shunting in critically ill patients |journal=Crit. Care Med. |volume=16 |issue=12 |pages=1243–5 |year=1988 |pmid=3191742 |doi=}}</ref> | Comparative studies suggest this measure correlates better with pulmonary shunts than does the A-a gradient.<ref name="pmid6409506">{{cite journal |author=Covelli HD, Nessan VJ, Tuttle WK |title=Oxygen derived variables in acute respiratory failure |journal=Crit. Care Med. |volume=11 |issue=8 |pages=646–9 |year=1983 |pmid=6409506 |doi=}}</ref><ref name="pmid14769743">{{cite journal |author=El-Khatib MF, Jamaleddine GW |title=A new oxygenation index for reflecting intrapulmonary shunting in patients undergoing open-heart surgery |journal=Chest |volume=125 |issue=2 |pages=592–6 |year=2004 |pmid=14769743 |doi=}}</ref><ref name="pmid3191742">{{cite journal |author=Cane RD, Shapiro BA, Templin R, Walther K |title=Unreliability of oxygen tension-based indices in reflecting intrapulmonary shunting in critically ill patients |journal=Crit. Care Med. |volume=16 |issue=12 |pages=1243–5 |year=1988 |pmid=3191742 |doi=}}</ref> | ||
==References== | ==References== | ||
{{reflist|2}} | |||
Revision as of 12:47, 23 August 2010
In pulmonary medicine and anesthesiology, the P:F ratio is the ratio of arterial oxygen concentration to the fraction of inspired oxygen. It reflects how well the lungs absorb oxygen from expired air. [1]
An example in a healthy person:
A higher ratio indicates better gas exchange:
- Normal is 500
- ARDS is < 200
Comparative studies suggest this measure correlates better with pulmonary shunts than does the A-a gradient.[2][3][4]
References
- ↑ Caroline Helwick, P/F Ratio May Be a Marker of Potential Intraoperative Ventilator-Induced Lung Injury, "Coverage of the American Society of Anesthesiologists (ASA) 2009 Annual Meeting", Medscape Medical News
- ↑ Covelli HD, Nessan VJ, Tuttle WK (1983). "Oxygen derived variables in acute respiratory failure". Crit. Care Med. 11 (8): 646–9. PMID 6409506. [e]
- ↑ El-Khatib MF, Jamaleddine GW (2004). "A new oxygenation index for reflecting intrapulmonary shunting in patients undergoing open-heart surgery". Chest 125 (2): 592–6. PMID 14769743. [e]
- ↑ Cane RD, Shapiro BA, Templin R, Walther K (1988). "Unreliability of oxygen tension-based indices in reflecting intrapulmonary shunting in critically ill patients". Crit. Care Med. 16 (12): 1243–5. PMID 3191742. [e]