Acid-Base Disorders Flashcards
• pH less than 7.35 – 7.45
• Reflects excess acid or H+ concentration
Acidemia
• pH greater than 7.35 – 7.45
• Reflects excess base
Alkalemia
• Caused by ventilatory dysfunction (a change in pCO2 )
Primary Respiratory Disorder
• Resulting from a change in the HCO 3-ion leve
Metabolic (Nonrespiratory) Disorder
• The body tries to restore acid-base homeostasis whenever an imbalance occurs
• Body accomplishes this by altering the factor not primarily affected by the pathologic processes
• If the imbalance is of metabolic origin, the body compensates by altering the ventilation
Compensation
Compensation
• For disturbances of the RESPIRATORY COMPONENT, the kidneys compensate by…
selectively excreting or reabsorbing anions and cations
Compensation
• For disturbances of the RESPIRATORY COMPONENT, the kidneys compensate by selectively excreting or reabsorbing anions and cations
•______ can compensate immediately, but the response is short term and often incomplete
Lungs
Compensation
• Kidneys are slower to respond (_____), however, the response is____ term and potentially complete
2-4 days
long
• Compensation
________
• Implies that the pH has returned to the normal range (the 20:1 ratio has been restored)
________
• Implies that the pH is approaching normal
Fully Compensated
Partially Compensated
• Decrease in bicarbonate, resulting in a decreased pH as a result of the ratio for the nonrespiratory to respiratory component less than____
Primary Metabolic Acidosis
20:1
• May be caused by the direct administration of an acidproducing substance
• By excessive formation of organic acids as seen with diabetic ketoacidosis and starvation
Primary Metabolic Acidosis
• Reduced excretion of acids (renal tubular acidosis)
• Excessive loss of bicarbonate from diarrhea or drainage from a biliary, pancreatic, or intestinal fistula
Primary Metabolic Acidosis
Primary Metabolic Acidosis
• Compensation
• Through______, which is an increase in the rate or depth of breathing
• By “blowing off”____, the base-to-acid ratio will return toward normal
• Secondary compensation occurs when the “original” organ (kidney) begins to correct the ratio by retaining bicarbonate
hyperventilation
CO2
Primary Respiratory Acidosis
• Results from a decrease in_______, causing a decreased elimination of CO2 by the lungs
alveolar ventilation (hypoventilation)
Primary Respiratory Acidosis
•_______, destructive changes in the airways and alveolar walls increase the size of the alveolar air spaces, with the resultant reduction of the lung surface area available for gas exchange
• As a result, CO2 is retained in the blood, causing chronic_____
•_______, gas exchange is impeded because of the secretions, wbcs, bacteria, and fibrin in the alveoli
COPD
hypercarbia
Bronchopneumonia
Primary Respiratory Acidosis
•______ caused by drugs, mechanical obstruction, and asphyxiation, will increase blood pCO2 levels
• Decreased cardiac output (CHF), less blood presented to the lungs for gas exchange, and therefore, an elevated pCO2
Hypoventilation
Primary Respiratory Acidosis
• Compensation
• Occurs through nonrespiratory processes
• Kidneys increase the excretion of H+ and increase the reabsorption of HCO3-
• Begins immediately, but it takes days to weeks for maximal compensation to occur
Primary Metabolic Alkalosis
• Results from a gain in HCO3-, causing an increase in the nonrespiratory component and increase in the pH
Primary Metabolic Alkalosis
• Results from excess administration of _______\ or through ingestion of bicarbonateproducing salts
• Excessive loss of acid
• Vomiting
• Nasogastric suctioning
• Prolong use of diuretics that augment renal excretion of H+
Sodium bicarbonate
Primary Metabolic Alkalosis
• Compensation
• Depressing the respiratory center
•_____ increases the retention of carbon dioxide
Hypoventilation
• Results from an increased rate of alveolar ventilation causing excessive elimination of carbon dioxide by the lungs
Primary Respiratory Alkalosis
• Hypoxemia
• Chemical stimulation of the respiratory center by drugs
• Increase in the environmental temperature
• Hysteria, anxiety (hyperventilation)
• Pulmonary emboli
• Pulmonary fibrosis
Primary Respiratory Alkalosis
Primary Respiratory Alkalosis
• Compensation
• Kidneys excrete______ in the urine and reclaiming H+ to the blood
• Popular treatment for hysterical hyperventilation: breathing into a paper bag
HCO3-
Specimen Collection for ABG
• Arterial Blood
Heparinized plastic syringe
Glass syringe pretreated with heparin
Heparinized evacuated tubes
Blood samples should be chilled with the use of_____ to prevent O2 consumption by the rbc and release of acidic metabolites
ice chips
SOURCES OF ERROR
Specimen exposed to air
Specimen at room temperature more than 30 minutes
↓ PCO2; ↑ pH, ↑ PO2
↓ PO2; ↓ pH. ↑ PCO2
