We are going to start posting questions or statements to start a significant discussion group.
Our goals are to :
- Start a wide berth of discussions.
- establish synergies of thought.
- improve patient care.
- improve interdisciplinary communications.
- introduce varied approaches to healthcare.
- decrease length of intubation.
- decrease length of time to liberation from mechanical ventilation.
- decrease length of hospital stay.
- decrease the cost of health care.
- introduce new or variant concepts of ICU care.
Here is the first 2 of many thought provoking statements.
Evoking Epipheny – 2019-05-001
Evaluate your patient’s P/F ratio :
P/F ratio = PaO2 / FiO2 ratio.
It is a great way to index your patient’s oxygenation status.
It is cheap and not complicated but tells a lot about your lung in 30 seconds.
HOW TO CALCULATE P/F RATIO :
Divide PaO2 by FiO2 (in decimal format).
Normal P/F ratio value : 500-600 (on any FiO2).
Normal patient : (breathing room air)
PaO2 = 100 , FiO2 = 21% >> PaO2 / FiO2 ratio = 100 / 0.21 = 500.
Normal patient : (breathing 100% FiO2 via NRB (non-breather)).
PaO2 = 600, FiO2 = 100% >> PaO2 / FiO2 ratio = 500 / 1.00 = 500.
WHAT ARE DIAGNOSTIC VALUES :
P/F ratio > 500-600 = Normal.
P/F ratio < 300 = ALI.
P/F ratio < 200 = ARDS.
P/F ratio < 150 = AHRF (acute hypoxemic respiratory failure).
WHAT IS THE AVERAGE SURGICAL PATIENT’S P/F VALUE :
P/F ratio on arrival from operating theatre / room : PaO2 = 250, FiO2 = 100% >> P/F ratio = 250s.
P/F ratio 4 hours after surgery : PaO2 = 120, FiO2 = 50% >> P/F ratio = 250s.
The patient was on the following ventilator parameters in the CTICU : SIMV-VCV, RR(set)=8, Vt(set)=700, FiO2=50%, PEEP=5.
The patient will be in the MRI suite for the next 75 minutes.
a) what will the settings be on this ventilator ?
b) how do you set patient trigger ?
c) how do you set Vt(set) on this ventilator (the “cheat sheet” was ripped off of the side of this ventilator).
d) if you use the vent with the settings that are currently dialed in, what will the ventilators translate to in standard ventilator parameters.
In a nutshell :
SBAR – quick / rapid report handoff format adopted by hospitals.
why the submarine pic ? SBAR format was initially designed by submarine personnel.
The long winded version :
(in a submarine : deep, deep underwater with limited oxygen supply and tons of crushing pressure all around, there is not time for lengthy speeches – its more like “you have 2 seconds to tell me what’s wrong and how you would fix it”.
I was told a long time ago, by my supervisor back then, “don’t come to me with just a problem … have a suggested solution as well”. I have always liked that management style and give her credit for introducing me to that notion.
The third point, always know the history of anything and everything (in this case : SBAR came from the military).
We should treat a patient in crisis just like we were having a crisis in a submarine :
tell me the problem.
give me relevant background quickly.
tell me why you think the problem happened.
tell me how you would fix it.
Normal P/F ratio=600.
As a generalization :
everybody breathing room air (21%) will have an PaO2=100. P/F ratio=100/0.2 = 500.
everybody breathing 100% oxygen via NRB will have an PaO2=500. P/F ratio=500/1=500.
so now, you can figure out the max PaO2 on any FiO2.
FiO2 P/F ratio PaO2
100% 600 600
90% 540 600
80% 480 600
70% 420 600
60% 360 600
50% 300 600
40% 240 600
30% 180 600
21% 120 600