Assessment of Cardiovascular Function
Throughout the continuum of care, whether in a home, hos-pital, or rehabilitation setting, all patients with cardiovascular dis-ease (disorders of the heart and major blood vessels; CVD) require similar assessments. Key components of the cardiovascular assess-ment include obtaining a health history, performing a physical assessment, and monitoring a variety of laboratory and diagnostic test results. An accurate and timely assessment of cardiovascular function provides the data necessary to identify nursing diagnoses, formulate a plan of care, and evaluate the response of the patient to the care provided. Essential to the development of these assess-ment skills is an understanding of the structure and function of the heart in health and in disease.
The heart is a hollow, muscular organ located in the center of the thorax, where it occupies the space between the lungs (medi-astinum) and rests on the diaphragm. It weighs approximately 300 g (10.6 oz), although heart weight and size are influenced by age, gender, body weight, extent of physical exercise and condi-tioning, and heart disease. The heart pumps blood to the tissues, supplying them with oxygen and other nutrients.
The pumping action of the heart is accomplished by the rhyth-mic contraction and relaxation of its muscular wall. During systole (contraction of the muscle), the chambers of the heart become smaller as the blood is ejected. During diastole (relaxation of the muscle), the heart chambers fill with blood in preparation for the subsequent ejection. A normal resting adult heart beats approx-imately 60 to 80 times per minute. Each ventricle ejects approximately 70 mL of blood per beat and has an output of approximately 5 L per minute.