Acid Base Balance

Metabolic Acidosis

• pH < 7.35 , bicarb < 22

• Pathophysiology:

  • increase in hydrogen ions: DKA(ketones), CKD/CFR, eating disorder(ketones), alcohol(ketoacidosis), excessive exercise + decrease perfusion + antidiabetic drugs(lactic acid), salicylate toxicity, potassium sparring diuretics

  • decrease in bicarbonate

    • Excessive loss from GI tract: diarrhea, fistula, lax use

  • increase in chloride ions

    • cause less bicarb to be release in the blood. IVF

Metabolic Acidosis Clinical Manifestations

• General: malaise

• Neurological: decrease LOC, headache

• Cardiovascular: dysrhythmias, bradycardia

• Respiratory: hyperventilation, dyspnea

• GI: low app, N/V, abd pain

• Integumentary: warm, flushed (vasodilation for better delivery of bicarb)

• Musculoskeletal: weakness, fatigue (acid cause muscle breakdown)

Metabolic Acidosis Therapy

• Sodium Bicarbonate

• Sodium citrate (CKD)

• Sodium lactate (turn in bicarb)

• Activated Charcoal

• Use sodium with caution in renal and heart failure

Metabolic Alkalosis

• pH >7.45, bicarb > 26

• Pathophysiology:

  • decrease in hydrogen ions

    • vomiting (loss of hydrochloric acid)

    • Increased renal excretion of hydrogen ions can be prompted by hypokalemia

  • increase in bicarbonate

    • treat GERD/heartburn, gastric suctioning

  • decrease in chloride ions

    • loop diuretics

Metabolic Alkalosis: Treatment

• Excessive vomiting: antiemetics, rehydrate/ rpl fluids

• Excessive use of loop diuretics such as furosemide (loss of chloride ions): hold or d/c med

• Excessive use of sodium bicarbonate (baking soda) as a remedy or GERD: stop use of baking soda

Metabolic Alkalosis Clinical Manifestations

• Neurological: decreased CO2, confusion, numbness and tingling

• Cardiovascular: dysrhythmias, hypotension (fluid loss (GI))

• Respiratory: resp failure (hypoventilation)

• Musculoskeletal: hyperreflexia, tetany, seizure

Respiratory Acidosis

• pH < 7.35, CO2 > 45

Potential causes:

• Overdose on a narcotic/ sedative

• Lung diseases affecting the total volume of air inhaled and exhaled with each breath- COPD, asthma, pneumonia, pulmonary edema, cystic fibrosis

• Foreign body aspirations or blockages

Chronic hypercapnia (elevated CO2 renal compensation, increased HCO3, pH is normal)

Respiratory Acidosis: treatment

Overdose of a narcotic

• Administer Narcan

Lung diseases

• Antibiotics, bronchodilators/ duonebs, corticosteroids

• Increase rate/ depth of respirations: use continuous positive airway pressure (BIPAP) or mechanical ventilation

• Hypoxia- administer oxygen

• Secretions- percussion, vibration, postural drainage

• Positioning- HOB elevated, turn & reposition Q2H

Foreign body aspiration

• Bronchoscopy- remove foreign body

Respiratory Acidosis: S&S

Headache, blurred vision

• Warm, flushed skin

• Muscle twitching

• Irritability or altered mental status

• Decreased LOC

• Tachycardia, dysrhythmias, cardiac arrest

• Acute respiratory acidosis can lead to impaired consciousness, coma, and death.

• Manifestations of chronic respiratory acidosis include dull headache, sleep disturbances, impaired memory, and personality changes. Slow process

Respiratory Alkalosis: pathophysiology/ etiology

Hyperventilation. CO2 breathed off exceeds the amount produced by the body during normal metabolism.

• Release of epinephrine

• panic attack, anxiety, pain, stress

• Excess thyroid hormone

• hyperthyroidism/ Graves disease- increases body metabolism

• Increased oxygen demand

• fever, infection, excessive heat, high altitudes, pulmonary causes

• Overdose of salicylate drugs

• body will try to compensate by increasing respirations

Respiratory Alkalosis: clinical manifestations

• Hypocalcemia can result from alkalosis(elevated blood pH increases the binding of ionized calcium to albumin): numbness and tingling of extremities, muscle spasms, Chvostek and Trousseau signs

• Vasoconstriction and decreased cerebral perfusion: lightheadedness

• With anxiety and hyperventilation: chest pain, tachycardia, dysrhythmias

Respiratory Alkalosis Treatment

Teach patient to slow breathing/ pursed lip breathing

Hyperventilation

• Provide a calm, quiet environment; anxiolytics; analgesics, benzodiazepines

Thyroid storm

• meds, radiation, surgery

Conditions that increase the body’s oxygen demand: fever/infection

• Antibiotics, antipyretics

High altitudes

• Provide supplemental oxygen