Page 25 - Basic Monitoring in Canine and Feline Emergency Patients

elevations may be associated with other concurrent includes recommendations as to how to use lactate
comorbidities such as lipidosis and interpreted for monitoring. Key points to remember when
VetBooks.ir accordingly. including lactate as a diagnostic tool are: (i) a single
isolated reading is of little diagnostic or prognostic
Lactate value; (ii) serial values or trends should be moni-
tored; and (iii) lactate values are only one piece of
Lactic acidosis is an increase in blood lactate that the global picture and should be reviewed in com-
results in an acidemia. Hyperlactatemia is classi- bination with other diagnostic results and physical
fied as type A or type B. Type A hyperlactatemia exam findings.
occurs as a consequence of decreased delivery of
oxygen to tissues. Type B hyperlactatemia is
divided into three categories related to the cause. 1.5 Pitfalls of the Point-of-care Meters
See Table 1.9 for classifications of hyperlac-
tatemia and their causes. Blood glucose
The use of lactate clinically as an indicator of As simple as the use of point-of-care glucose
severity of disease and response to therapy has meters is, there are some pitfalls to be aware of
been evaluated. Its use as an adjunct diagnostic with this instrumentation. It is important to
indicator when assessing cavitary effusions has also ensure the instrument as well as any necessary
been investigated. Table 1.10 lists a variety of dis- disposables are stored and handled properly.
ease entities where lactate has been evaluated as a Make sure all strips and cartridges are in date
biomarker for severity of disease or prognosis and and strips are kept in a sealed container. Proper

Table 1.9. The classifications of lactic acidosis and potential causes of each.
Classification Pathophysiology Disease examples
Type A Systemic hypoperfusion Shock
Sepsis
SIRS
Local hypoperfusion Arterial thromboembolism
Burns
Organ torsion
Impaired hemoglobin carrying capacity for oxygen Carboxyhemoglobinemia
Methemoglobinemia
Severe anemia Hemoglobin <5 g/dL (PCV <15%)
Severe hypoxemia PaO <30 mmHg
2
Increased oxygen demand Exercise
Seizures
Shivering
Trembling/tremors
Type B1 Diseases associated with decreased lactate clearance Severe liver failure
Neoplasia
Sepsis
Diabetes mellitus
Thiamine deficiency
Kidney Injury
Type B2 Drugs and toxins that impair oxidative phosphorylation Propylene glycol
Prednisone
Type B3 Metabolic defects leading to abnormal mitochondrial function Insufficient pyruvate
hydrogenase
Mitochondrial myopathies
SIRS, systemic inflammatory response syndrome; PCV, packed cell volume; PaO , arterial partial pressure of oxygen.
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Physical Examination and Point-of-care Testing 17