Acidosis And Alkalosis .... SID

First of all
Strong Ion Difference SID means

SID = ([Na+] + [K+] + [Ca2+] + [Mg2+]) – ([Cl] + [other strong anions: A]) = 40–44 mEq

If all other factors (PCO2, albumin, and phosphate) are kept constant, an increase in SID will decrease hydrogen ion liberation from water (and increase hydroxyl ion liberation), causing alkalosis

Decrease in SID increases hydrogen ion liberation, to maintain electrical neutrality, causing acidosis

The chief determinant of SID is the relationship between the relative concentration of sodium, chloride and free water in ECF

The normal ratio of sodium to chloride is approximately 1.4:1. Any process that reduces that ratio reduces SID and leads to acidosis (sodium loss, chloride gain, or free water gain). Any process that increases that ratio increases SID and leads to alkalosis (sodium gain, chloride loss, or free water gain)

Second Acid–base disturbances are an importantnpart of clinical and laboratory investigation of perioperative and critically ill patients.

There are 6 primary acid–base abnormalities
(ATOT:weak acids)

1. Acidosis as a result of increased PaCO2

2. Acidosis as a result of decreased SID: increased chloride (hyperchloremic), reduced sodium (dilutional)/ increased free water

3. Acidosis as a result of increased ATOT(weak acids): hyperphosphatemia, hyperproteinemia

4. Alkalosis as a result of decreased PaCO2

5. Alkalosis as a result of increased SID: decreased chloride (hypochloremic), increased sodium/decreased free water (contractional)

6. Alkalosis as a result of decreased ATOT: hypophosphatemia, hypoalbuminemia

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