Nancy Shaffran, CVT, VTS (ECC)
The overall goal of anesthesia is survival and optimum recovery from surgery. In order to accomplish this goal, the surgery patient must be continually monitored for changes, especially deterioration in respiration, cardiac function and tissue perfusion regardless of the specific surgery.
Delivery of adequate oxygen to tissues and cells is the overall goal of the cardiovascular system. Oxygenation is dependant on cardiac output (heart rate and stroke volume), arterial blood pressure, circulating blood volume, and pulmonary function. Critically ill patients often have impairments to one or several of these processes resulting in hypoxemia, ischemia and cell death. Restoring these functions to normal insures oxygenation.
The most common causes are defective heart muscle, valvular disease, cardiac tamponade, electrical malfunction, heartworms or administration of drugs with profound cardiac effects. In any case, when heart failure results in circulatory collapse and inadequate tissue oxygenation, the patient is said to be in cardiogenic shock. The term "cardiogenic shock" describes a shock syndrome where cardiac output is reduced as a direct result of heart failure.
Cardiovascular (ECG, CVP, blood pressure) monitoring is essential to detect patient changes and to direct therapy and supportive care.
The pulmonary system is complex with various anatomical structures performing highly specialized functions. When evaluating the system it is useful to examine each structure for its unique function and associated potential complications. Physical assessment and monitoring tools such as pulse oximetry and arterial blood gas analysis are used to localize respiratory problems and guide treatment which may include supplemental oxygen therapy, appropriate drugs or pulmonary physiotherapy.
Feline heartworm disease is more common than previously believed, often fatal and completely preventable. It is now estimated that 26% of cats may be infected with heartworm disease. This is very significant especially when compared to 5% who are FeLV positive and 6% who have FIV.