/*Draft for trail of explaining acidbase.org algorithm in simple way check acidbase.org and http://www.acid-base.com/interpretation.php for more information */
Just trial for creating simple -not too much 
– algorithm for quantitative analysis of acid base disturbances using Stewart Fencel approach
The following data will be needed for calculation pH, Na, Cl, K, Albumin, HCO3 values
History.. read the patient lab .. for prediction of expected disturbance”s”.
Check pH ..
pH more than or equal 7.4 … overall disturbance is alkalosis
pH less than 7.4….over all disturbance is acidosis
| pH | Interpretation |
| < 7.1 | Severe acidosis |
| 7.1 7.25 | Moderate acidosis |
| 7.25 7.35 | Slight acidosis |
| 7.35 — 7.45 | Normal range |
| 7.45 7.5 | Slight alkalosis |
| 7.5 7.6 | Moderate alkalosis |
| >7.6 | Severe alkalosis |
Non-respiratory deviation:
overall Non-respiratory deviation could be calculated from “Corrected Base Excess -SBEc-” ….see later.
Values used for evaluation /*just for approximation*/:
Alkalosis
| Severe > 13 Marked 13 to 9 Moderate 9 to 6 Mild 6 to 4 Minimal 4 to 2 |
Normal 2 to -2
Acidosis
| Minimal -2 to -4 Mild -4 to -6 Moderate -6 to -9 Marked -9 to -13 Severe < -13 |
Non-respiratory deviation could be originated form disturbance in SID and/or ATOT
SID deviation occurs in abnormality in water content, expressed by Na value and/or Cl Value, and value of Unknown anions “XA“
starting form SBEc 0
Na deviation effect could be calculated from
Na effect = 140-(Observed Na)
any deviation from zero will be added or removed to base excess value
Hyponatremic acidosis or hypernatremic alkalosis terms could be used for identifying source of SID deviation
Cl deviation effect could be calculated from
Cl effect = 105-(observed Cl)/*taking 105 as mean between 102-108 “normal Cl values “*/
Hyperchloermic acidosis or hypocholermic alkalosis terms could be used for identifying source of SID deviation
any deviation from zero will be added or removed to base excess value
XA:for calculation if XA you will need ATOT value for calculating SIDe
XA=SIDa-SIDe
ATOT value could calculated using albumin value “Phosphorus value will be omitted from calculation”
Albumin effect = 11-(2.8*albumin “g/dl”)
any deviation from zero will be added or removed to base excess value
the terms hypoalbuminmic alklosis and hyper albuminic acidosis may be used for identifying ATOT quantity of deviation
now calculating XA
XA=SIDa-SIDe
SIDa=Na+K+Ca+Mg-Cl=observed Na+ observed K+ 6+ observed Cl /* value 6 for replacing values of Ca and Mg*/
SIDe=(2.8*albumin)+HCO3+2 /*vaule 2 for replacing Phosphorus value */
normal vale of XA in critically ill patient 2-8 mEq/l any elevation form that value will be considered as unknown anion acidosis
SBEc could be calculated by adding all element of deviation together (Na effect+ Cl effect +albumin effect + Unknown anion effect with consideration of negative and positive values)
Respiratory component could evaluated using the following “mmhg”
Alkalosis
| Severe < 18Marked 18 to 25 Moderate 25 to 30
Mild 30 to 34 Minimal 34 to 37 |
Normal 37 to 43
Acidosis
| Minimal 43 to 46 Mild 46 to 50 Moderate 50 to 55
Marked 55 to 62 Severe > 62 |
Example
Case of methyl poisoning
pH = 7.29
SBE=-18 mEq/l
Na= 135 mEq/l
K=4 mEq/l
Cl=113 mEq/l
CO2=15.7 mmhg
Albumin=2.2 g/dl
HCO3 = 7.6 mEq/L
Interpretation
pH 7.29 means slight acidosis
Na effect=140-135=5 mild hypontremic acidosis.. negative value will be applied as that is decrease of SID
Cl effect = 105-113= -8 moderate hypercholermic acidosis
Albumin effect = 11-(2.8*2.2)=4.8 mild hypoalbuminmic alkalosis
XA effect = (135+6+4-113) – (2.8*2.2+7.6+2)=16.2 unknown anion have will have negative value = -16.2 Severe unknown anion acidosis
~SBEc=-5-8-16+4.8=-24= server non respiratory acidosis
Respiratory component : 15.7 Sever respiratory alkalosis
For evaluation of compensation winter rules may be used : compensated non respiratory acidosis with over decrease of CO2 value by ~2 mmhg of expected range
any modifications, corrections are welcome