Overview of the CardiovascularSystem: This system is powered by the heart, which pumps blood, oxygenated by the lungs, throughout the body to distribute oxygen. The blood also collects waste products from the cells, like carbon dioxide. Problems with the heart or blood vessels can result in permanent damage to the body or death due to lack of oxygen, so it is extremely important that ailments are recognized and appropriate actions taken. Following this slide are examples of a few procedures done to keep the cardiovascular system up and running.
Cardiac Echocardiography:taking a sonogram of the heart Often referred to as a cardiac ECHO, this procedure should not be confused with electrocardiography. An ECHO uses ultrasound techniques, using sound waves to create a highly detailed picture of a moving heart. Many observations can be made using an echocardiogram, especially using the latest systems which use 3D imaging in real-time.
How echocardiograms are performed:Transthoracic echocardiogram: Anechocardiography transducer (probe whichpicks up echoes of sound waves, thenconverts them into moving images) is placedon the patient’s thorax, noninvasivelyproducing images through the chest wall. Thestandard way, very fast and accurate,pictured right. Transesophageal echocardiogram: The probe is passed through the patient’s esophagus; used when a transthoracic procedure does not produce a clear enough picture. Rarely used. Stress echocardiogram: Images are first taken at rest, then compared to images produced when a patient is exercising in order to assess the heart during physical activity.
What echocardiography can tell us: Accurate observations and evaluations of the following can be made using echocardiography: health of cardiac tissue and valves congenital heart disease the velocity of blood ischemia leaks and regurgitation in the heart cardiac output the size and shape of the heart atrial fibrillation heart murmurs pericarditis endocarditis
Extracorporeal circulation:circulation of blood outside the body During cardiopulmonary bypass, or open-heart surgery, gravity drains blood from the superior and inferior vena cavae into a heart-lung machine’s reservoir. This blood is then pumped through a membrane oxygenator, which oxygenates the blood. Finally, the blood is pumped back into the body via the aorta. Sensors regulate blood temperatures, oxygen saturation, blood gases, pH, and pressure.
How the heart-lung machine attaches tothe cardiovascular system: Rigid cannulas are inserted into the vena cavae and aorta.
Although most patients recover successfully,there are complications associated withextracorporeal circulation: arrhythmias Atrial, caval, or aortic tears/bleeding injury/obstruction due to malpositioning of cannulas air embolization ischemia epicardial vessel damage unstable angina
Thrombolytic therapy:the use of drugs to dissolve blood clotsTissue plasminogen activator (tPA) is the mostcommonly used drug to break up blood clots andrestore blood flow. It is an enzyme that catalyzes theconversion of plasminogen into plasmin (an enzymewhich breaks down blood clots).Other drugs can also be used,such as streptokinase andlanoteplase.
When are thrombolytics are used? When clotting in the body is obstructing blood flow and causing problems. Ischemic strokes are caused by clots in the brain and if there is no bleeding, thrombolytics can quickly dissolve these clots. Best results occur within three hours of the first stroke symptoms. Heart attacks occur when a clot is blocking the arteries to the heart and some of the cardiac tissue dies. Thrombolytics can restart perfusion and prevent cardiac damage, but will only be used if there is no bleeding within the body or high blood pressure.
Complications of thrombolytictherapy: Although there are not many complications, hemorraging and internal bleeding is the most common risk and, in some cases, can be life-threatening. In about 25% of patients, minor bleeding from the gums can occur. In about 1% of patients, bleeding of the brain can occur.