Post on 01-Jan-2016
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Acid-Base Balance
Acids- rise in pHDonate or give up H+ ions
Nonvolatile acids or fixed acids Inorganic acids that occur through metabolism of
CHO, protein, lipid Average amount 50-100 mmol/day Proteins contribute the most Lungs cannot eliminate
Acid-Base Balance
BasesCan accept or receive H+ ions
Bicarbonate HCO3
Kidneys provide primary regulation
Acid-Base Balance
pHAcidosis
Accumulation of acid or loss of base
AcidemiapH less than 7.35
Alkalosis- rare Accumulation of base or loss of acid
AlkalemiapH greater than 7.45
Regulation of Acid-Base Balance
Chemical buffers- in the middle, maintain the acid base balance, bicarbonate
Respiratory regulation- increase the rate and the depth of your breath CO2 production/excretion is increased
Kidney regulation- reabsorb more bicarbonate if in a acidic condition
Regulation of Acid-Base Balance
Respiratory regulatory control
Change in respiration rate
Depth of breathing
Release or retention of CO2
Regulation of Acid-Base Balance
Renal regulatory control
Control of HCO3 (bicarbonate) by the kidneys
Increased or decreased based on need Formation of dibasic phosphate and sulfur in the
urine Accepts H+
Regulation of Acid-Base Balance
Electrolyte Balance- Work on TPN solution to make sure they are not in acidosis
Hydrogen and bicarbonate both electrolytesOther electrolytes affected to maintain
electroneutralityPotassium, chloride, sodium
Acid-Base Disorders
4 major typesRespiratory acidosis- lower pH, higher plasma,
bicarb, increased CO2 production excretes more H from the kidneys to alter this
Respiratory alkalosis- pH up, bicarb, plasma and CO2 down
Metabolic acidosis- lower pH, decreased plasma, bicarb, CO2
Metabolic alkalosis- increased pH, plasma, bicarb, CO2, kidneys increase bicarbonate excretion
Acid-Base Disorders
Respiratory acidosisExcess acid in blood secondary to carbon dioxide
retentionHypercapnia- too much CO2 in the blood, breathing
to compensate that (hyperventilate) Common causes d/t respiratory dysfunction – renal regulatory
systems compensate
Acid-Base Disorders
Respiratory acidosisLabs
Decreased pH, elevated pCO3
Slightly elevated bicarbonate Increase in serum Ca, K, Cl (lab values)
Hypoxemia- decreased partial pressure in the blood, decreased flow of O2 in the blood
Restlessness, apprehension, lethargy, muscle twitching, tremors, convulsions, coma
Acid-Base Disorders
Respiratory acidosisTreatment
Correct underlying condition bring up the bicarbonate Increase oxygenation Mechanical ventilation
Acid-Base Disorders
Respiratory alkalosis (hyperventilation) CO2 eliminated faster than it can be replaced Relative excess amount of base d/t reduction of CO2
HyperventilationCommon causes - see Table 9.6Shift of acid from ICF to ECF Bicarbonate moved into cells in exchange for
chloride – renal compensation if they are functioning properly
Acid-Base Disorders
Respiratory alkalosispH > 7.45 Plasma HCO3 low in chronic, PaCO3 low in acute
Cardiac, CNS, respiratory symptomsTreating underlying cause as a medical teamCorrection of hypoxia
Acid-Base Disorders
Metabolic Acidosis All types not caused by excessive CO2
Common causes Diarrhea most common cause
d/t excessive loss of bicarbonate – bicarbonate-carbonic acid buffer system is stimulated
Acid-Base Disorders
Metabolic Acidosis Kussmaul breathing- deep labored breathing Cardiac and neurological (as a result of being
acido.) Treat underlying cause Raise pH to safe level – not too quickly
Acid-Base Disorders
Metabolic Alkalosis- RARE, from overuse of base, medically induced
Excess amount of base Fluid imbalance – with volume decrease Without fluid imbalance – without volume
decrease Common causes Underlying event determines pathophysiology-
what is going on to cause them to lose this acid??