13/08/2024
لو عندنا عيان عنده Respiratory Failure و محتاجين نحدد ال severity و نشوف هل هو بيتحسن ولا لا، ممكن نقيسها ازاي؟🫁
PF Ratio i.e. (PaO2/FiO2 Ratio):
PF ratio is an essential tool for quantifying the severity of acute respiratory distress syndrome (ARDS). 🩻
ايه هو ال PaO2 ✔️
PaO2 is the partial pressure of O2 gas in the arterial blood و دا بنقيسه عن طريق تحليل ال ABG للدم
Normal values of PaO2 75:100 mmHg
و ايه هو ال FiO2 ✔️
FiO2 is the fraction of inspired O2 at room air
يعني الهوا اللي احنا بنتنفسه، دا بيكون
mixture of gases
و ال FiO2 دا بيقيس نسبة ال O2 في الهوا العادي
At all conditions, the concentration of oxygen in the gas mixture, at room air is 21%
ودي نسبة ثابته مابتتغيرش طول ما الشخص اللي
بيتنفس مش محطوط علي اي O2 support وبيتنفس هوا الاوضة العادي
طيب ايه هو ال rationale behind the PF ratio ?
لو تخيلنا سيناريو ان عندنا
2 patients as illustrated in this picture, patient (A) is intubated on MV, with set FiO2 100% and patient (B) is at room air (RA) with the normally FiO2 at 21%.
On measuring the PaO2 for both patients, they both measures 90 mm Hg, however, surprisingly they are NOT THE SAME in terms of their health conditions.
دا معناه اننا محتاجين نشوف value تاني غير ال PaO2 يقدر يreflect the severity for both patients, so we use the PF ratio
طيب هحسبها ازاي؟
هقسم ال PaO2 علي ال FiO2
As for patient (A) PF ratio is 90 which means a very critical and severe respiratory failure, and as for patient (B) PF ratio is 428 (a normal healthy adult).
