Shock is a state of circulatory collapse or acute severe dysfunction in which tissue circulation and oxygen delivery is compromised. If untreated, multi-organ failure and death result. Shock is the final common pathway of numerous disease states.
Shock can be broadly classified into the following categories:
- Hypovolaemic - e.g. blood loss (motor vehicle accident, internal hemorrhage)
- Cardiogenic - e.g. congestive heart failure
- Septic - e.g. bacterial, fungal
- Endocrine - e.g. Addisonian crisis
- Hypersensitivity/Anaphylactic - e.g. acute allergic response to drugs, insects, toxins
Clinical signs are for the most part non-specific, and include pale mucous membranes, tachycardia, hypotension, gallop rhythm, oliguria, and altered consciousness.
Management of shock in cattle is generally supportive and involves aggressive intravenous fluid therapy.
Specific treatment for the underlying disorder is unlikely to be effective in the short term with the exception of adrenaline in anaphylaxis or hydrocortisone in Addisonian crisis. As specific therapy will lead to dramatic improvement in these patients, it is critical to consider both conditions early in the resuscitation and treat appropriately.
- IV fluids
IV fluids are given as boluses (5 ml/kg of 6% hexastarch in 0.9% sodium chloride given over 5 minutes).
Crystalloid fluids are then given at 10 ml/kg/hr. Active warming of the cow is recommended.
Once stabilised, IV crystalloids such as Hartmann's solution with 20 mmol/L potassium chloride supplementation, at 4 ml/kg/hr.
Analgesia is given - e.g. methadone 0.1 mg/kg IV.
Constant rate analgesic infusions once stabilised, e.g. morphine-ketamine IV.
Antibiotics, such as broad-spectrum amoxycillin-clavulanate, are given parenterally at 30 mg/kg.
If hypotension is present, dopamine is administered at 5.1-7.2 μg/kg/min.