Question

A 56-year-old man with a history of diabetes mellitus and alcoholism presents after having eaten no food and taken no insulin for the last 3 days. He reports drinking “lots” of alcohol. The patient presents with low blood pressure, abnormally high resting heart rate, and an abnormally elevated rate of ventilation (36 breaths/minute). He smells strongly of acetone and is dehydrated. Clinical findings are consistent with left lower lobe pneumonia. Results of ABG testing are: PO2 = 68 mm Hg, PCO2 = 17 mm Hg, HCO3- = 6 mEq/L, and pH = 7.30.

1. What is the acid-base disturbance?
2. Is he attempting to compensate? Explain your answer.
3. What would his acid-base profile be if his respiratory rate were 14 breaths/minute?

Answer 1

Ans

it is complication of diabetes

ABG given :-

pH= 7.30 - less , normal value = 7.35-7.45 ....... (7.4)

pO2 = 68 mmhg - too low noraml value is =100 mmhg it is hypoxemia

pCO2= 17 mmhg - less noramal value is 35-45(40)

HCO3- = 6 meq/l - noraml value = 22-26(24)

As per data :

look at pH - acidic

pCo2 - alkaline

HCO3- -acidic

case is METABOLIC ACIDOSIS as pH acidic nature due to HCO3 -

2. check compensation

in metabolic acidosis

1 meq/l fall in HCO3- ----> 1.2 mmhg Fall in pCO2

so in this case

HCO3- fall from 24 to 6 = 24-6= 18

so fall in pCO2 should be = 18 x 1.2 = 21. 6 mm hg ==22 mmhg

so expected pCO2 = 40-22 = 18 mmhg

given pCO2 = 17 mmhg

so compessation is done he is attempt to compensate .

3. if RR rate is changes from 36 to 14 beats then

CO2 is unable to wash out from lung and CO2 pressure raised lead to respiratory acidosis

acid base disorder become both respiratory and metabolic acidosis with decompensation