A cardiac catheter used for right ventricular catheterization that determines cardiac output in addition to measuring pressure is known as a Swan-Ganz catheter. The balloon catheter is inserted into the right ventricle and pulmonary artery via central nervous access. It is applied primarily in intensive care monitoring.
What is a Swan-Ganz catheter?
The Swan-Ganz catheter was developed in 1970 by cardiologists W. Ganz and H. J. Swan. It is a cardiac catheter for the right ventricle that is used in pressure measurement and determination of cardiac output. The examinations with the Swan-Ganz catheter are also called right heart catheterization. This examination is mainly used to monitor the cardiovascular situation in intensive care patients or during anesthesia. The catheter is placed percutaneously through a central nervous access. Through the right atrium of the heart, the catheter reaches the right ventricle and is advanced into the trunk of the pulmonary artery. The procedure is associated with numerous risks, but these are rare. Nevertheless, the patient is informed beforehand about the risk of nerve injury, injured cardiac structures, vascular damage, thrombosis and embolism.
Forms, types, and species
The Swan-Ganz catheter is usually a balloon catheter. These are used primarily in angioplasty or urinary bladder catheterization. Balloon catheters are a plastic catheter that carries a balloon of compressed air or fluid at the tip. The balloon can deploy and is also called an occlusion balloon. If cardiac output is to be measured in addition to pressure, a thermistor catheter is used. Such a catheter measures the temperature dilution curve in the heart and uses it to calculate the volume that the heart ejects per minute. Like the balloon catheter, the thermistor catheter is a three-lumen catheter. The individual lumina are separated from each other. As a cardiac catheter, the Swan-Ganz catheter in all forms is considered a right heart catheter. For right heart catheters, a vein of the groin is usually punctured. The puncture allows the insertion of a cannula and a guide probe. The guide probe is used to remove the cannula, and the cardiac catheter can be inserted.
Structure and mode of operation
The Swan-Ganz catheter is composed of several individual units. In addition to a balloon, it includes a double-lumen catheter with X-ray markings, a pressure-measuring chip, and a syringe for the balloon. By means of the inflatable balloon, the lumen of the structure can be expanded or closed. During surgery, for example, the blood flow can be momentarily interrupted. As a rule, the balloon is inflated with one milliliter of air via the syringe. The balloon then moves into the wedge position as a result of the heartbeat. It is thus fixed in a branch of the pulmonary artery. The catheter is connected to the individual measuring devices via various ports. The pressure measurement takes place by means of the pressure chip in the right atrium, right ventricle and pulmonary artery. Through this pressure measurement, conclusions are drawn about the function of the heart cavities. Information can also be gathered regarding lung function and the body’s water balance. For this reason, the pulmonary catheter is used primarily in anesthesia and for patients with cardiac insufficiency or during cardiovascular surgery. Intensive care medicine also uses the catheter in patients in shock. Such shock states may include cardiogenic shock, septic shock, or polytraumatic hypovolemic shock. The measuring devices evaluate the information from the pressure chip and give pressure values. Ideally, these values enable the intensive care physician to determine the cause of a shock condition and thus decide on a specific treatment. For example, he or she can elucidate whether drug treatment is sufficient or whether surgical intervention such as puncture of the pericardium is necessary.
Medical and health benefits
Through the Swan-Ganz catheter, various pressure conditions in the heart and nearby structures can be determined. For example, the pulmonary artery can be occluded by the catheter’s balloon. The resulting pressure is called pulmonary artery occlusion pressure and is also known as wedge pressure.This pressure is used indirectly to determine end-diastolic pressures in the left ventricle. Such a determination may be required for indications for pulmonary isangiography. Such indications include pulmonary embolism, pulmonary arteriovenous fistula, pulmonary valve regurgitation, or planned mitral or aortic valve replacement. Indications for dextrocardiography may also necessitate the Swan-Ganz catheter. Such an indication presents with tricuspid and pulmonary valve dysfunction, right-to-left shunt ventricular dysfunction or atrial septal defects, and pulmonary vein malapposition. In addition, left ventricular dysfunction may necessitate the pressure measurement described. Such disturbances occur, for example, as a result of left heart failure, in the context of pulmonary hypertension or cor pulmonale. Since the Swan-Ganz catheter can also be used to determine cardiac output, it is also of medical use in cases of bradycardia, pronounced tachycardia, structurally ischemic cardiac changes or altered cardiac loads. It can be equally useful in valve damage, filling obstructions, pericardial tamponades and thoracic deformities. In addition to its function as a monitoring tool, the Swan-Ganz catheter also serves as a diagnostic tool for treatment planning. Despite the associated risks, a catheter has a correspondingly high medical benefit and is therefore frequently used, especially in critically ill patients.
