Page 318 - Fluid, Electrolyte, and Acid-Base Disorders in Small Animal Practice

Mixed Acid-Base Disorders 309

TABLE 12-4 Evaluation of Mixed Metabolic Disorders
Chloride Contribution* Unmeasured Strong Anion Contribution

NORMAL AG or AG or
SIG simplified > 5 mEq/L or SIG simplified < 5 mEq/L or
UA strong > 5 mmol/L UA strong < 5 mmol/L
# [Cl ]gap, Hyperchloremic acidosis Hyperchloremic acidosis and " unmeasured strong anion acidosis

# [Cl ]/[Na ]or
þ

# [Na ] [Cl ]

þ

Normal [Cl ]gap, Normal " Unmeasured strong anion acidosis
þ

Normal [Cl ]/[Na ] or Normal
[Na ] [Cl ]
þ

" [Cl ]gap, Hypochloremic alkalosis Hypochloremic alkalosis and " unmeasured strong anion acidosis

" [Cl ]/[Na ]or
þ

þ
" [Na ] [Cl ]

AG, Anion gap; SIG simplified , simplified strong ion gap; UA strong , unmeasured strong anions estimated using the base excess algorithm; [Cl ]gap, chloride
þ

gap; [Cl ]/[Na ], chloride to sodium ratio; [Na ] [Cl ], sodium to chloride difference.
þ
*Metabolic compensation in chronic respiratory acid-base disturbances can also change chloride concentration.
BOX 12-6 Examples of Potential Causes of Counterbalancing Mixed
Acid-Base Disorders
Mixed Respiratory and Metabolic Disorders Severe exercise
Respiratory Acidosis and Metabolic Alkalosis Acute tumor lysis syndrome
Pulmonary edema and diuretics Severe canine babesiosis caused by Babesia canis rossi
Gastric dilatation-volvulus Cardiopulmonary resuscitation (only in arterial blood)
Respiratory Alkalosis and Metabolic Acidosis Mixed Metabolic Disorders
Hypoadrenocorticism-like syndrome in dogs with Metabolic Acidosis and Metabolic Alkalosis
gastrointestinal disease Gastric dilatation-volvulus
Septic shock Renal failure with vomiting
Salicylate toxicity Vomiting and lactic acidosis
Heat stroke Renal failure and loop diuretics
Gastric dilatation-volvulus Diabetic ketoacidosis with vomiting
Liver disease (RTA and impaired metabolism of lactate) Severe canine babesiosis caused by B. canis rossi
Pulmonary edema with hypoxemia or low cardiac output Liver disease (hypoproteinemia, diuretics, vomiting, RTA,
Parvovirus gastroenteritis and sepsis and impaired metabolism of lactate)
RTA, Renal tubular acidosis.

8. Correlate the clinical and laboratory findings. Box 12-6 shows examples of potential causes of
9. Plan individualized therapy. counterbalancing mixed acid-base disorders.

MIXED ACID-BASE Respiratory Acidosis and Metabolic
DISTURBANCES Alkalosis
This combination is an uncommon clinical situation, and
in human medicine it usually occurs in patients with
DISORDERS WITH NEUTRALIZING chronic lung disease who develop vomiting or who are
EFFECTS ON pH treated with diuretics. It may occur in acute situations
6
Patients with mixed disorders comprised of primary in dogs with gastric dilatation-volvulus that can present
problems with an offsetting effect on pH may have a nor- with metabolic alkalosis caused by loss of gastric acid
mal, low, or high pH. When pH is abnormal, however, and respiratory acidosis resulting from diaphragmatic
2
because of the counterbalancing effect of the second compression caused by the distended stomach. The

primary disorder, changes tend not to be pronounced. PCO 2 and [HCO 3 ] are high, and the pH tends to be