Laura Barron, Module 2

Acid-Base Disturbances - Brunners

Ratio

20parts of HCO3-(Bicarbonate) : 1part H2CO3(Carbonic Acid)

CO2 is a potential Acid. When dissolved in water → H2CO3 Carbonic Acid

Laura Barron, Module 2

Regulation by Kidney – Slow

R Acidosis & most cases of M Acidosis:

K. ↓ (excrete) H+ and ↑ (conserve) HCO3-

R & M Alkalosis

↑ H+ ↓HCO3-

Kidney Failure M Acidosis cannot be compensated

Regulation by Lungs – Control by Medulla O.

M. Acidosis

↑respiration ↓ CO2

M. Alkalosis

↓ respiration rate ↑CO

Laura Barron, Module 2

  • Acute and Chronic Metabolic Acidosis (Base Bicarbonate Deficit)

↓ pH and ↓ bicarb(allowing the high acidic value)

Anion Gap

Na+ + K+ - Cl- - HCO3- = Anion Gap

Norm: 12-16mEq/L or 8-12 w/o K+

  • 16 acidosis (Normal anion gap) resulting from: loss of bicarbonate: diarrhea, lower intestinal fistulas, diuretics, early renal insufficiency, excess admin chloride, admin of nutrition w/o bicarbonate (lactate) = hyperchloremic acidosis.
  • 30 metabolic acidosis regardless of pH and HCO3-. resulting from: ketoacidosis, lactic acidosis, salicylate poisoning, starvation.
  • Negative gap is rare caused by hypoproteinemia.
  • s/s:Clinical manifestations – headache, confusion, drowsiness, increased resp rate/depth, N & V. Seen in Chronic Renal Failure.
  • Assessment and diagnostic Findings
  • HCO3- < 22 ph<7.35
  • Hyperkalemia may occur, and then shift back into the cell after.
  • Hyperventilation decreases CO2 – Compensatory action.
  • MedicalManagement – bicarbonate (low ca treated first from chronic met acidosis to avoid tetany)
  • Acute and Chronic Metabolic Alkalosis (Base Bicarbonate Excess)

high pH high bicarbonate. Vomiting, gastric suction.loss of potassium from diuretic. Excessive adrenocorticoid hormones, hypokalemia, excessive ingestion of antacids.

  • Clinical Manifestations – tingling of fingers and toes, dizziness, hypertonic muscles. Respirations depressed as compensatory action bylungs. tachycardia, decreased motility and paralytic ileus. as K+ decreases chronic met alk. has premature ventricular contractions or U waves on ECG.
  • Assessment and Diagnostic Findings – ph > 7.45, hco3- 26mEq/L
  • Medical Management – monitor I/O because of fluid loss.IVF NS w/chloride allows binding with bicarb to excrete. Then any treatment of KCL-
  • Acute and Chronic Respiratory Acidosis (Carbonic Acid Excess)

ph< 7.35, paCO2 > 42. Always due to inadequate excretion of CO2 – ventilation. Acute pulmonary edema, aspiration of a foreign object, Atelectasis, Pneumothorax, overdose of sedatives, sleep apnea syndrome, impaired respiratory muscles – mechanical ventilation.

  • Clinical Manifestations – increase pulse and respiratory rate, incr blood pressure, feeling of fullness in head, mental cloudiness. increased cerebral blood flow. Chronic – emphysema, bronchitis, obesity. COPD may not develop symptoms of Hypercapnia because of compensatory renal changes have occurred.
  • Assessment and Diagnostic Findings - ph< 7.35, paCO2 > 42, chest xray ECG
  • Medical Management – improve ventilation Bronchodilators, Antibiotics, Thrombolytics/anticoagulants. Pulmonary hygiene to clear resp tract of mucus. Adequate Hydration! O2 as necessary. Decrease elevated paCO2 slowly. Semi-Fowler’s position to expand chest wall.
  • pco2 > 50 chronically – O2 may cause carbon dioxide narcosis when removing the stimulus of hypoxemia. Extreme caution.
  • Acute and Chronic Respiratory Alkalosis (Carbonic Acid Deficit)

ph > 7.45 paco2 < 38. Always caused by Hyperventilation blowing of co2. causes extreme anxiety, hypoxemia, salicylate intoxication

  • Clinical Manifestations – light headedness Vaso Constriction, decreased cerebral blood flow. inability to concentrate, numbness and tingling from decreased calcium, tinnitus, LOC, Tachycardia, Dysrhythmia.
  • Assessment and Diagnostic Findings – Compensated state kidneys have lowered bicarb to near normal level. Toxicology screen should be performed to rule out salicylate intoxication.
  • Medical Management – if Anxiety. Breathe slowly to allow CO2 to accumulate or into paper bag. sedative.
  • Mixed Acid-Base Disorders

normal pH with changes in paco2 and hco3-. (Can’t have mixed R Acid & R Alka – you can’t hyper and hypo ventilate.) Met Acid and Resp Acid – during respiratory and cardiac Arrest.

  • Compensation – lungs and kidneys compensate to return the pH to normal.
  • Blood Gas Analysis–