The direct indexes obtained from Swan-Ganz balloon floating catheter are right atrial pressure (RAP), pulmonary artery pressure (PAP), pulmonary artery entrapment pressure (PCWP) and cardiac output (CO). Indirect indexes calculated by the formula include pulmonary circulation resistance (PVR), systemic circulation resistance (SVR), stroke work (SW), left ventricular stroke work (LVSW), right ventricular stroke work (RVSW) and cardiac index (CI). If necessary, a mixed venous blood sample can be collected through a catheter to determine the venous oxygen partial pressure (PvO). ), indirectly understand the ventilation function.
Method:
Pressure measuring device and catheter flushing device:
1. Adjust the zero point: make the transducer at the same level as the patient's heart, and twist the tee to make the transducer communicate with the atmosphere. When the pressure value of the monitor shows zero, it means that the zero adjustment is completed.
2. Flush each lumen to make the sensor communicate with one lumen.
3. Prepare the cardiac output computer, adjust it to the ready working state, input the patient's blood temperature and control the ice water temperature in vitro. Suck 10ml sterile iced saline repeatedly with 10ml syringe and connect it to the end of the catheter leading to the right atrial cavity.
4. Push the iced saline quickly within 4S, and press the cardiac output computer at the same time, and the machine will display the cardiac output value.
5. Record PAP, PCWP, BP, HR and RAP synchronously.
PAP: It is measured by communicating the sensor with the lumen leading to pulmonary artery.
PCWP: On this basis, the catheter balloon is inflated and the catheter floats into the pulmonary capillaries.
RAP: It is measured by communicating the sensor with the lumen leading to the right atrium.
Blood pressure and heart rate: measured by conventional methods.
Present, Past and Future of Floating Ducts
The floating catheter was put into use on 1970, which can be completed even if the critically ill patient is at the bedside for a few minutes. Although it is not difficult to place these catheters, some training and experience are necessary in order to obtain reliable hemodynamic data through pulmonary artery intubation and reduce the occurrence of complications. Because balloon floating catheter has many advantages compared with traditional catheter, it is used in patients without indications and overused in intensive care unit, which leads to many complications and increases mortality.
Prospective randomized controlled studies report that in most clinical cases, the routine use of floating catheters has no indication. These results are not surprising, because floating catheter is a diagnostic method rather than a treatment. We used floating catheter to monitor critically ill patients and obtained a lot of hemodynamic data. In addition, through direct detection of hemodynamics, we have gained a wealth of clinical knowledge and experience about hemodynamics.
It should also be recognized that despite the increase and improvement of non-invasive imaging methods, floating catheter is needed to detect hemodynamics in some clinical situations, but only experienced doctors can complete this operation. The correct use of floating catheter monitoring has greatly improved our understanding of hemodynamics. Its abuse, especially by relatively inexperienced operators, will lead to serious complications and even death.
Prospective randomized clinical trials show that routine use of floating catheters will not bring any benefits. However, floating catheters can still be used in many clinical situations.