Fraction of inspired oxygen

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The inspired oxygen fraction ( Fi O ₂ ) is the fraction or percentage of oxygen in the measured volume. Medical patients who have difficulty breathing are provided with oxygen-rich air, which means higher than the Fi O ₂ atmosphere. Natural air includes 21% oxygen, which is equivalent to Fi O ₂ of 0.21. Oxygen-rich air has Fi O ₂ higher than 0.21; up to 1.00 which means 100% oxygen. Fi O ₂ is usually maintained below 0.5 even with mechanical ventilation, to avoid oxygen toxicity. If a patient wears a nasal cannula or simple facial mask, each extra liter/minute of oxygen adds about 4 percentage points for each of the first 3 liters and only 3 percentage points for each liter thereafter to their Fi O
₂ (for example, a patient with a nasal canal with 4L/min oxygen flow will have Fi O
₂ of 21% (3 ÃÆ'â €" 4%) (1 ÃÆ'â € "3%) = 36%).

Often used in medicine, Fi O ₂ is used to represent the percentage of oxygen participating in gas exchange. If barometric pressure changes, Fi O ₂ can remain constant when the oxygen partial pressure changes with a change in barometric pressure.

Video Fraction of inspired oxygen

Persamaan

Disingkat persamaan udara alveolar

${\ displaystyle P_ {{ce {O2}} = {\ frac {P_ {E} {\ ce {O2}} - P_ {i } {\ ce {O2}} {\ frac {V_ {D}} {V_ {t}}}} {1 - {\ frac {V_ {D}} {V_ {t}}}}}} Â Â$

P _A O ₂ , P _E O ₂ , and P _i O < sub> 2 is the partial pressure of oxygen in alveolar, expired, and inspired gas, respectively, and VD/VT is the ratio of physiological dead space to the tidal volume.

Maps Fraction of inspired oxygen

Medicine

In the medical world, Fi O ₂ is the percentage assumed from the oxygen concentration that participates in the gas exchange in the alveoli.

src: pediatrics.aappublications.org

Usage

The Fi O ₂ is used in APACHE II (Acute Physiology and Chronic Health Evaluation II) severity of the disease classification system for intensive care unit patients. For Fi O ₂ values ​​equal to or greater than 0.5, the alveolar-arterial gradient value should be used in APACHE II score calculations. If not, Pa O ₂ will suffice.

The ratio between the partial pressure of oxygen in arterial blood (PaO2) and Fi O ₂ is used as an indicator of hypoxemia per US-European Consensus Conference on lung injury. High Fi O ₂ has been shown to change the ratio Pa O ₂ / Fi ₂ .

src: circ.ahajournals.org

PaO2/FiO2 ratio

The ratio of partial arterial oxygen to the pressure and the inspired oxygen fraction, sometimes called Carrico Index , is the ratio between the oxygen level in the blood and the inhaled oxygen concentration. It helps to determine the extent of the problem with how the lungs transfer oxygen to the blood. Arterial blood samples were collected for this test. The PaO2/FiO2 ratio of less than or equal to 200 is required for the diagnosis of acute respiratory distress syndrome by AECC criteria. The newer Berlin criteria define mild ARDS with a ratio of & lt; 300.

A Pa O
2 / Fi O
2 ratios less than or equal to 250 is one of the minor criteria for severe community acquired pneumonia (ie a possible indication for inpatient care).

A Pa O
2 / Fi O
2 ratio less than or equal to 333 is one of the variables in the SMART-COP risk score for respiratory support or intensive vasopressor in community-acquired pneumonia.

Example calculation

After drawing the ABG from the patient, PaO2 was found 100mmHg. Because the patient receives O2-saturated air to produce 50% oxygen FiO2 calculated Pa O
2 / Fi O
2 the ratio will be 100 mmHg/0,5 = 200.

src: erj.ersjournals.com

Related maths

Alveolar air equations

Persamaan udara alveolar adalah rumus berikut, yang digunakan untuk menghitung tekanan parsial gas alveolar:

${\ displaystyle P_ {{ce {O2}} = F_ {I} {\ ce {O2}} (PB-P {\ ce { H2O}}) -P_ {A} {\ ce {CO2}} \ kiri (F_ {I} {\ ce {O2}} {\ frac {1-FI {\ ce {O2}}} {R}} \ right)} Â Â$

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Lihat juga

• Toksisitas oksigen

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Reference

Tautan eksternal

• FiO2 oleh Perangkat Pengiriman - Menampilkan FiO2 oleh sistem pengiriman oksigen umum.

Source of the article : Wikipedia