Acid and Base Balance, Arterial Blood Gas Values – Nursing Pathophysiology N54A

normal pH range
7.35 – 7.45
plasma buffer
carbonic acid + bicarbonate + hemoglobin
respiratory acidosis
*pH < 7.35* - high *PPCO2* from ventilation depression - increased CO2 & H+ COMPENSATION - renal HCO3 retention and H+ excretion CLINICAL MANIFESTATIONS - heachache, restless, lethargy, twitching TREAT: restore ventilation, give lactate ringers solution
respiratory alkalosis
*pH > 7.45* *PPCO2 < 38 mmHg* - low CO2 from hyperventilation, salicylate toxication COMPENSATION - renal H+ retention, HCO3 elimination CLINICAL MANIFESTATIONS - dizziness, confusion, paresthesias, hypocalcemia TREAT: paper bag, treat hypoxemia
metabolic acidosis
*HCO3 < 24 mEq/L* - low HCO3 or increase of noncarbonic acids - lactic acidosis, renal failure, diarrhea, ketoacidosis COMPENSATION - hyperventilation to eliminate CO2, renal acid excretion CLINICAL MANIFESTATION - headache, lethargy, deep long breaths TREAT: bicarbonate, lactate ringers solution
metabolic alkalosis
*HCO3 > 26 mEq/L*
– high bicarbonate from loss of metabolic acids (Cl-)
– hyperaldosteronism, diuretic therapy
– hypoventilation to retain CO2
– kidneys conserve H+ and excrete bicarbonate
– weakness, muscle cramps, hyperactive reflexes, hypocalcemia
TREAT: sodium chloride, potassium, chloride IV to replace bicarbonate
acidemia causes ventilation to…
increase, to lower CO2
alkalosis causes respiration to…
decrease, to increase CO2 and lower pH
high pH and low PPCO2 indicates…
respiratory alkalosis
low pH and high PPCO2 indicates…
respiratory acidosis
high pH, high HCO3 (bicarbonate), and high CO2 indicates…
metabolic alkalosis
low pH, low HCO3 (bicarbonate), and low CO2 indicates…
normal ABG levels:
7.35 – 7.45 pH
35 – 45 mmHg
22 – 26 mEq/L
75 – 100 mmHg

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