Shock

From Dog
Hypovolemic shock in a dog due to rodenticide poisoning[1]

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
Sepsis - e.g. bacterial, fungal
Endocrine - e.g. hypoadrenocorticism
Anaphylaxis - 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 dogs is generally supportive and involves aggressive IV 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 dog is recommended.

Once stabilised, IV crystalloids such as Hartmann's solution with 20 mmol/L potassium chloride supplementation, at 4 ml/kg/hr.

Serum levels of cortisol, the main endogenous corticosteroid, generally increase with shock, particularly when sepsis is involved. Administration of dexamethasone, hydrocortisone or prednisolone may suppress an excessive inflammatory response, reverse sepsis-induced vascular hyporeactivity and treat any underlying adrenal insufficiency[2].

Analgesia is given - e.g. butorphanol

Constant rate analgesic infusions once stabilised, e.g. morphine-ketamine IV.

  • Antimicrobial therapy

Antibiotics, such as broad-spectrum enrofloxacin or amoxycillin/clavulanate are given parenterally.

  • Miscellaneous

If hypotension is present, dopamine is administered at 5.1-7.2 μg/kg/min[3].

References

  1. Animal Central
  2. Hicks CW et al (2012) Efficacy of selective mineralocorticoid and glucocorticoid agonists in canine septic shock. Crit Care Med 40(1):199-207
  3. Kuan, SY et al (2010) Intestinal strangulation after elective ovariohysterectomy. JFMS 12:325-329