Page 2138 - Cote clinical veterinary advisor dogs and cats 4th

1065.e2 Blood Gas Analysis

Canine Expected Compensation • A mixed acid-base disturbance is characterized Alternatives and Their
by at least two primary acid-base abnormali- Relative Merits
Compensatory
Primary
VetBooks.ir Disorder Change Response ○ Because overcompensation never occurs, of oxygenation but information is not
ties in one patient.
• Pulse oximetry: less invasive assessment
equivalent
if the expected compensatory response is
−
0.7 mm Hg decrease
Metabolic
↓HCO 3
in PCO 2 for each
acidosis
• Lactate measurement
may have occurred.
1 mEq/L decrease in not present, a mixed acid-base disturbance • End-tidal CO 2 if patient is intubated
− ○ Compensation does not return pH to
HCO 3
Metabolic ↑HCO 3 − 0.7 mm Hg increase normal, with the exception of chronic SUGGESTED READING
alkalosis in PCO 2 for each respiratory alkalosis. DiBartola SP: Introduction to acid–base disorders.
1 mEq/L increase in ○ In a patient with a primary metabolic In DiBartola SP, editor: Fluid, electrolyte, and
− process, compensation is not considered acid-base disorders in small animal practice, ed
HCO 3
Acute ↑PCO 2 1.5 mEq/L increase appropriate if the PaCO 2 differs from 4, St. Louis, 2012, Saunders, pp 231-252.
−
respiratory in HCO 3 for each expected compensation by > 2 mm Hg. ADDITIONAL SUGGESTED
acidosis 10 mm Hg increase ○ In a patient with a primary respiratory
process, compensation is not considered READINGS
in PCO 2 −
Chronic ↑PCO 2 3.5 mEq/L increase appropriate if HCO 3 differs from DiBartola SP: Mixed acid-base disorders. In DiBartola
−
respiratory in HCO 3 for each expected compensation by > 2 mEq/L. SP, editor: Fluid, electrolyte, and acid-base disorders
acidosis 10 mm Hg increase • Quick tip to suspect a mixed disorder: a in small animal practice, ed 4, St. Louis, 2012,
change in pH in the opposite direction to Saunders, pp 302-315.
in PCO 2 Middleton DJ, et al: Arterial and venous blood gas
Acute ↓PCO 2 2.5 mEq/L decrease the predicted primary disorder. tensions in clinically healthy cats. Am J Vet Res
−
respiratory in HCO 3 for each • Treatment should be aimed at cor- 42:1609-1611, 1981.
alkalosis 10 mm Hg decrease recting underlying cause of acid-base Additional chapters in this book
abnormality.
in PCO 2 Lactate, Section 4, Laboratory Tests
Chronic ↓PCO 2 5.5 mEq/L decrease Postprocedure Blood pH, Section 4, Laboratory Tests
−
respiratory in HCO 3 for each Acid-Base Disorders, Section 5, Algorithms
alkalosis 10 mm Hg decrease • If arterial sample is collected, a pressure
wrap should be placed over site to prevent AUTHORS: Katie D. Mauro, DVM; Lori S. Waddell,
in PCO 2 DVM, DACVECC
bleeding.
• Address recognized acid-base disturbances EDITORS: Leah A. Cohn, DVM, PhD, DACVIM; Mark S.
Thompson, DVM, DABVP
Feline Expected Compensation or disorders of ventilation and oxygenation.
Primary Compensatory
Disorder Change Response
Metabolic ↓HCO 3 − PCO 2 does not
acidosis change
Metabolic ↑HCO 3 − 0.7 mm Hg increase
alkalosis in PCO 2 for each
1 mEq/L increase in
−
HCO 3
Acute ↑PCO 2 1.5 mEq/L increase
−
respiratory in HCO 3 for each
acidosis 10 mm Hg increase
in PCO 2
Chronic ↑PCO 2 Unknown
respiratory compensatory
acidosis response
Acute ↓PCO 2 2.5 mEq/L decrease
−
respiratory in HCO 3 for each
alkalosis 10 mm Hg decrease
in PCO 2
Chronic ↓PCO 2 5.5 mEq/L decrease
−
respiratory in HCO 3 for each
alkalosis 10 mm Hg decrease
in PCO 2

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