Pressure monitoring is one of the important functions of the hemodialysis machine. When the pressure value exceeds the preset alarm range, the machine will emit a sound and light alarm. At this time, the operator must correctly analyze and determine the cause of the alarm and take appropriate measures. Interventions to ensure the safety of dialysis patients.
Compared with venous pressure and transmembrane pressure, monitoring of anterior pump artery pressure (abbreviated herein as arterial pressure) is often not given much attention. Many dialysis rooms (centers) do not monitor arterial pressure, dialysis machine so that changes in arterial pressure can not be reflected in time. When it comes out, it will not be able to eliminate all kinds of hidden dangers in a timely manner.
Arterial pressure monitoring reflects the pressure required to draw blood from the arterial end of the patient's vascular access to the blood pump segment. The K/DOQI vascular access clinical practice guidelines recommend that the pre-pump pressure should not be lower than -250 mmHg because excessive negative pressure can lead to decreased actual blood flow, inadequate dialysis, and hemolysis. Monitoring of changes in arterial pressure is of great clinical importance.
Affects actual blood flow
The blood pump is the dynamic component of the extracorporeal blood circulation, and the blood flow is closely related to the blood pump speed and the diameter of the pump tube. The pump tube has a certain elasticity. dialysis machine The blood pump wheel and the pump body press the pump tube. A sealed blood chamber is formed between the two blood pump wheels. When the blood pump rotates, the blood flows.
The rotational speed of the blood pump can be controlled by the blood pump motor, but the volume of the closed blood chamber formed between the two blood pump wheels changes with the degree of filling of the pump tube. Arterial pressure is the primary factor that affects the actual blood flow. If the arterial pressure is too low, it will lead to dissatisfaction of the pump tube, which in turn will cause the actual blood flow to be lower than the set blood flow. The effect of arterial pressure on the actual blood flow was studied experimentally. The study showed that, regardless of the size of the needle diameter, when the pre-pump arterial pressure was lower than -150 mmHg, the actual blood flow was significantly lower than the set blood flow rate. The decrease in the actual blood flow not only results in insufficient dialysis, but also has a significant effect on post-dilution of the filtered blood. dialysis machine Although venous pressure monitoring can also reflect changes in blood flow to some extent, its sensitivity is lower than arterial pressure monitoring.
Assessing Vascular Pathway Function
Arterial pressure monitoring is used to reflect the blood supply capacity of the vascular access. Monitoring results can be used as an indicator to evaluate the function of vascular access and can play a role in the management of vascular access.
When the blood flow is insufficient, the arterial pressure drop triggers an arterial pressure alarm, the nursing staff should be vigilant, check the blood, puncture needle, puncture point around the presence of abnormalities; dialysis machine if the dialysis blood flow continued to decline gradually, there may be blood vessels If the function of the pathway is poor, it should be communicated with the doctor as soon as possible to evaluate and intervene the patient's condition and reduce the occurrence of path loss.
Effect on hemolysis
It has been reported that shear stress is a major factor leading to hemolysis in hemodialysis. In the dialysis circuit, the puncture needle has the highest shear stress, the shear stress of the needle is related to the blood flow, dialysis machine and the blood flow is related to the pre-pump arterial pressure. The effect of arterial pressure on hemolysis was also studied. Studies have shown that, regardless of the size of the needle, the optimal pre-pump pressure to prevent hemolysis is greater than -150 mm Hg, and this value can also prevent a decrease in the actual blood flow.
