Emergency patients present special challenges because their underlying disease processes can cause immediate life-threatening problems that require rapid and aggressive intervention. In addition, the full extent of the animal's problems, injuries, or toxicity may not be evident for 24–48 hr after initial presentation. Problems can arise from an acute illness, toxicity, or injury; from a chronic illness that has decompensated; or from an unexpected complication of a concurrent illness. The status of all postoperative patients should be considered critical until life-threatening anesthetic or surgical complications are ruled out. The golden rule of emergency medicine is to treat the most life-threatening problems first.

Variables that contribute to the overall success of emergency treatment include the severity of the primary illness or injury, the amount of fluid or blood lost, age of the animal, previous health problems, the number and extent of associated conditions, time delay in instituting therapy, the volume and rate of fluid administration, and the choice of fluids (eg, crystalloid, blood components, or synthetic colloids). Therapy must be done at the right time, in the right amount, and in the right order. Therapeutic failures are generally a result of failing to act expeditiously at a crucial moment.

Specialized care often begins with the owner's initial telephone call. Instructing the owner on first aid and transport procedures can be life-saving for the animal. The clinic and staff must be in readiness, especially if more than one animal in critical condition arrives at the same time. The primary survey, or triage (see Evaluation and Initial Treatment of the Emergency Patient: Primary Survey (Triage) and Resuscitation), requires a quick and accurate assessment and decision regarding the stability of the animal. As life-threatening airway, breathing, and circulation problems are identified, immediate treatment is initiated. Once the animal has been stabilized, a more systematic and organized approach to the history and physical examination (secondary survey) and more specific diagnostic and therapeutic procedures aimed at the underlying etiology can be done.

Last full review/revision March 2012 by Rebecca Kirby, DVM, DACVIM, DACVECC; Andrew Linklater, DVM, DACVECC