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b-if ph is (7.4-7.45) in case of other abnormal values or mixed disordersthe primary disorder will be alkalotic disorderc-if ph is (7.35-7.45) and the other values are normal,the acid base status is within normal

############2-IF THERE IS ACID BASE DISORDER, IS IT METABOLIC OR RESPIRATORY?

Any primary change in pCo2 will cause respiratory disorder and will change the ph in opposite direction(in respiratory disorders, pco2 increases ph decreases and vice versa )Any primary change in Hco3 will cause metabolic disorder and will change the phin the same direction(in metabolic disorders, hco3 increases ph increases and vice versa )

for example :a-metabolic acidosis : ph decrease hco3 decrease co2 decrease (compensation)b-metabolic alkalosis : ph increase hco3 increase co2 increase (compensation)c-respiratory acidosis : ph decrease co2 increase hco3 increase (very slow compensation)

d_respiratory alkalosis: ph increase co2 decrease hco3 decrease (very slow compensation)

###############3-IF THERE IS METABOLIC DISORDER,IS RESPIRATORY COMPENSATION APPROPRIATE OR NOT?

Metabolic disorders usually are compensated by respiratory system quickly

while respiratory disorders are compensated by renal system but very slowly

A-FOR METABOLIC ACIDOSIS, THE PRIMARY DISORDER IS DECREASED HCO3 OR INCREASED METABOLIC ACID PRODUCTION LEADING TO ACIDOSIS.SO RESPIRATORY STIMULATION OCCURS TO WASH CO2 TO DECREASE THE ACIDITY OF BLOODFOR CALCULATION OF RESPIRATORY COMPENSATION WE CALCULATE EXPECTED CO2

EXPECTED PCO2=(1.5[HCO3]+8)2

OR SIMPLY last two digits of ph(the first way is more accurate)

B-FOR METABOLIC ALKALOSIS, RETENTION OF CO2 OCCURS TO DECREASE THE ALKALINITY OF

BLOODEXPECTED PCO2 = 6 mm for 10 mEq. rise in HCO3 ABOVE 24

Suspect if .............actual PaCO2 is more than expected : additional respiratory acidosisactual PaCO2 is less than expected : additional respiratory alkalosis

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##############4-If there is metabolic acidosis, is there a HIGH anion gap ?

ANION GAP IS CALCULATED AS FOLLOW:

Na-(Cl+ HCO3) =8-12 this is normal anion gap acidosisthe most important causes are severe diarrhea and renal tubular acidosis and adrenal insufficiency

If >12, THERE IS HIGH Anion Gap Acidosis

MOST IMPORTANT CAUSES ARE :(MUDPIES)M ethanolU remia##D iabetic Ketoacidosis##P araldehydeI nfection OR Sepsis (lactic acid)##E thylene GlycolS alicylate

##THE MOST common in our ER

###############5-IF THERE IS RESPIRATORY DISORDERS, IS IT ACUTE OR CHRONIC?ALSO IS IT COMPENSATED OR NOT?

for respiratory disorder ,we are more concerned about it is acute or chronic rather than if it is compensated as compensation by renal system takes placws veryslowly

A-in case of respiratory acidosis and respiratory alkalosis:

10 mm 0.08 change in pH ( Acute )Change leads toPaCO2(above or below 40) 0.03 change in pH (Chronic)

B-respiratorty acidosis will be compensated by increase of hco3 by 1mmol in acute condition. and 4mmol in chronic condition (this for each 10 mmhg in pco2 above40)

C-respiratory alkalosis will be compensated by decrease of hco3 by 2mmol in acut

e condition . and 5mmol in chronic condition (this for each 10 mmhg in pco2 below 40)

###############6-evaluation of gas exchange status

a- at first look at po2 if above 80, it is normal.

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if (60-80) there is hypoxiaif below 60 there is respiratory failure

b-to know type of respiratory failure, look to pco2if low pco2 type1 RF is present(hypoxic hypocapnic)if high pco2 type2 RF is present(hypoxic hypercapnic)

(. )