Acid Base Balance

pH

• normal pH 7.35-7.45

  • <7.35 = acidosis

  • >7.45 = alkalosis

• hydrogen ions

  • more = lower pH

  • less = higher pH

• kidney control bicarb

• lungs control CO2

Regulation

• carbonic acid - bicarb buffer system

  • control amount of h ions

    • carbonic acid = hydrogen + water

  • carbonic acid is a direct reflectant of co2

• goal of bicarb is to bind with h ions

• resp control - CO2 changes - instant

  • acidic = ↑ RR + R depth

  • alkaline = ↓ RR + R depth

• renal - HCO3 - bicarb - hours to days

  • acidic = H excreted in urine

  • alkaline = HCO3 excreted in urine

Acid Base Disturbances

• metabolic acidosis

  • lactic / dka ??

• resp acidosis

  • CO2 or carbonic always

• metabolic acidosis

• resp alkalosis

  • CO2 or carbonic always

Acidosis - too much H+

• built up excess acid

• loss of bicarb

  • 1 = acidosis

  • 2 = hyper k

Metabolic Acidosis

• build up of metabolic acids

• excessive loss of bicarb

  • poop - excessive diarrhea

    • causes:

      • salicylate (asprin) OD

      • DKA

      • renal failure

        • failure to excrete normal acids

        • cannot reabsorb bicarb

    • interventions:

      • tx cause

      • O2

      • fluids

      • monitor electrolytes

      • sodium bicarb

        • pH <7.1

      • dialysis

      • anti-diarrheal meds - stop bicarb loss

      • diuretics - ↑ H+ excretion - loop or thiazide

Resp Acidosis

• carbonic acid excess

• causes:

  • weakness of resp muscles

  • severe resp depression

  • obstruction

  • blocked alveoli gas exchange

• interventions:

  • early intervention

  • tx underlying

  • positioning

  • O2

  • meds

    • bronchodilator

    • steroids

    • mucolytics

    • nebulizers

  • incentive spirometer

  • mechanical vent - ↑ CO2 loss

  • ambulation

S/S of Acidosis

• metabolic

  • hyperk

  • dysrhythmias

  • confusion

• resp - high CO2 - potent vasodilator - cerebral edema

  • visual disturbances

  • HA

  • restless / agitation

  • confusion

  • drowsiness

  • coma

Alkalosis

• build up bicarb

• loss of acid

Metabolic Alkalosis

• bicarb excess or excessive acid loss

• low K - replace

• causes:

  • ingest large amounts of bicarb - antacids

  • excessive administraion of bicarb

  • loss of hydrochloric acid

  • diuretic therapy - H+ ion loss

• tx:

Resp Alkalosis

• ↑ RR = blowing off too much CO2

• causes:

  • anxiety

  • pain

  • fever

• tx:

  • tx underlying cause

    • anxiety

      • theraputic communication

      • distraction

      • etc

    • pain

      • assess

      • medicate prn

    • fever

• s/s - mimics hypocalcemia - check calcium levels

  • hypo k

  • anxiety / irritable

  • dizzy - hypotension

  • mental confusion

  • numbness / tingling

  • muscle twitching

  • tetany / seziures

Interpreting Blood Gases