Monitoring critical small-animal patients (Proceedings)
For a technician, the daily assessment of their critical care patients often begins with rounds. After receiving a brief verbal history and synopsis of presentation, diagnostics, and treatments a tech is ready to take over the care of that patient. Of primary importance is an initial hands on assessment. Only then will a tech be ready to monitor each patient according to its individual needs.
Recently there has been a list generated that discusses monitoring 20 items to assess critical patients each day. Many of those parameters will be included, but the primary body systems of cardiovascular, respiratory, neurologic, metabolic, and urologic systems will be discussed. Due to limited time, this presentation will highlight these systems since each one would require a book chapter to adequately cover the material. It is difficult to put these items in order of priority as the nature of a critical care patient is to change moment by moment. Rather a technician has to maintain an eye on the global patient to assess for not only the primary complaint, but also remote area body systems not directly related to the illness or injury.
Cardiovascular monitoringEach patient should be evaluated for heart rate, pulse rate and quality, mucous membrane color, and capillary refill time.
• Both bradycardia & tachycardia diminish cardiac output
• If bradycardia <40-60 bpm- perform a blood pressure to ensure adequate tissue perfusion
• Causes of bradycardia-drugs, pain, vagal reflexes, AV blocks, hyperkalemia
• Tachycardia rates >180 big dogs, >200 little dogs, >240 cats
• Causes of tachycardia-shock, hypovolemia, pain, hypoxemia, hyperthermia, sepsis, heart disease
• Palpate pulse rate & quality while ausculting the heart
• Pulse deficit indicates heart arrhythmia
• Estimate appropriate stroke volume
• Thready pulse indicates poor cardiac output
• Bounding pulse may indicate septic shock (vasodilation conditions)
• MM should be pastel pink color and moist
• Red injected color can indicate sepsis, hyperthermia, hypertension, carbon monoxide poisoning
• Pale/white indicates varying degrees of anemia or vasoconstriction
• Blue (cyanotic) equals lack of oxygen saturated hemoglobin and cannot be seen until PaO2<50
• Brown indicates acetaminophen toxicity
• Yellow indicates liver disease, bile duct obstruction, hemolysis, prior oxyglobin transfusion
• Dry/tacky membranes equal dehydration
• Prolonged CRT (>2seconds) can occur from hypovolemia, hypothermia, poor cardiac output, pain
• Rapid CRT can occur during sepsis, hyperthermia, or drugs (inhalation anesthesia)
An electrocardiogram is a staple of critical care monitoring and technicians should become accustomed to evaluating every ECG tracing for abnormal heart rhythms. Any patient that exhibits irregular rhythm and increased or decreased heart rate upon physical exam should be monitored several times a day.
Arterial blood pressure should be monitored several times a day on critical patients by either indirect or direct methods as appropriate for the severity of disease. Arterial blood pressure is the product of cardiac output, vascular capacity, and blood volume. If one of those factors is abnormal, neurohumeral reflexes will alter the others to maintain normal pressure.
Central venous pressure is a critical monitoring tool especially useful for assessing a patient's response to fluid therapy, possible fluid overload, or in conditions such as renal, cardiac, or pulmonary disease and during septic shock.
Cardiac output monitoring requires sophisticated catheters and devices as well as monitoring true oxygen delivery and oxygen consumption. These procedures are not commonly performed. More typically monitored is respiratory function and assessment of lung perfusion and ventilation. These will be discussed next.