Fazeela's Idiots Guide to Arterial Blood Gases PDF

Fazeela's idiots guide to understanding arterial blood gases… Fazeela's idiots guide to understanding arterial blood gases.docx Page 1 of 2 This preview may have altered the layout of this file. You can still download the original file. Faze...

Fazeela's idiots guide to understanding arterial blood gases… Fazeela's idiots guide to understanding arterial blood gases.docx Page 1 of 2 This preview may have altered the layout of this file. You can still download the original file. Fazeela’s idiots guide to Arterial Blood Gas Analysis What is an arterial Blood Gas and why do we measure this? Well as in the words.. we are looking at the gases in the arterial blood (since gases are cannot be weighed in mls, we measure how much there is through partial pressure (Pa). We need to know about the concentration of gases, as gases are involved in maintaining the exact PH of the blood. We need an accurate PH to keep the body in balance and keep the organs ticking along in harmony. The organs rely on an accurate PH to operate efficiently. Which organs are involved in keeping this PH at balance? Lungs: Through respiration (Remember when we ventilate the patient, we can adjust the rate and depth of breaths, increase O2, hyperventilate to remove CO2 from blood) Kidneys: Generate Bicarbonate (HCO3) and also excrete it. Bicarbonate (alkaline) mops up/buffers excess Hydrogen ions (acidic), producing CO2+ water, which we can always remove through controlled ventilation. p.s. the problem arises when the kidneys can no longer produce enough bicarbonate to buffer the acid (hydrogen) making the patient extremely acidotic. Let’s try and remember (or right at the back of my badge on a sticker) to eventually stick it the normal parameters in my brain. Normal PH Range: acidotic ≤ 7.35-7.45 ≥ alkalotic PaO2: 10-13Kpa (10 Kpa less than inspired air) So if you were giving 50% O2, you should get 40Kpa PaO2 (but remember you are giving O2 cos there is summat wrong with the breathing, so you might get a lower reading) PaCO2: alkiolotic ≤ 4.7-6.0Kpa ≥ acidic Remember this is the figure that matters more to decide whether this is respiratory acidosis (so long as the Bicarbonate shows normal range, or it could be that the bicarbonate was the preceding issue) HCO3 (Bicarbonate/alkaline (Like Gaviscon, which puts a cover on the acid heartburn): acidosis ≤ 22-26 mmol ≥ alkalosis. Remember if it is low, then the kidney aint producing enough and we can give bicarbonate, but it takes time cos this is to do with kidneys and absorption. But if it is too high then we cant take bicarbonate out of the system (I guess we can try to compensate by reducing ventilation rate so CO2 stays in the blood and balances things out to balance the overall PH??) BE (Base Excess): -2mmol-metabolic acidosis +2mmol- metabolic alkalosis This is how much acid or alkaline we need to correct the PH to 7.4 :