CPT® Code 90940

1. Indications

The hemodialysis access flow study (CPT® Code 90940) is indicated for the following conditions:

• Assessment of Graft Patency - This procedure is performed to evaluate the patency of arteriovenous grafts and fistulae, ensuring that they are functioning properly for effective hemodialysis.
• Detection of Stenosis - It is utilized to identify stenosis, or narrowing of the blood vessels, which can impede blood flow and lead to complications such as graft thrombosis.
• Monitoring of Blood Flow - The study is indicated for ongoing monitoring of blood flow in patients with existing vascular access, helping to prevent potential issues before they become critical.

2. Procedure

The hemodialysis access flow study involves several key procedural steps that are essential for accurate assessment of blood flow:

• Preparation and Setup - The procedure begins with the patient being connected to the hemodialysis machine as part of their regular treatment. Trained staff prepare the necessary equipment, including the ultrasound sensors that will be used to monitor blood flow.
• Placement of Ultrasound Sensors - Two ultrasound sensors are clipped onto the hemodialysis tubing blood lines. One sensor is attached to the tube that carries blood from the patient to the dialysis machine, while the other is placed on the tube that returns the cleansed blood back to the patient. This positioning is crucial for accurate measurement of blood flow dynamics.
• Injection of Isotonic Saline Solution - An isotonic saline solution is injected into the bloodstream. This saline bolus serves to dilute the blood, which is necessary for the subsequent ultrasound measurements. The dilution alters the ultrasound velocity, allowing for more precise detection of blood flow characteristics.
• Monitoring and Measurement - As the saline bolus travels through the tubing, the ultrasound sensors continuously measure changes in the ultrasound characteristics of the blood. These measurements provide real-time data on blood flow and help identify any abnormalities that may indicate issues such as stenosis.
• Data Evaluation - The data collected from the sensors are evaluated by the healthcare professional. This analysis is critical for determining the presence of any blood flow problems and deciding on any necessary interventions.
• Disconnection from Monitoring Device - Once the measurements are complete and the data has been analyzed, the sensors are disconnected from the hemodialysis tubing. The procedure concludes with the patient continuing their hemodialysis treatment as needed.

3. Post-Procedure

After the hemodialysis access flow study is completed, there are typically no specific post-procedure care requirements beyond the standard care associated with hemodialysis. Patients may continue their dialysis session as scheduled. It is important for healthcare providers to monitor the patient for any immediate reactions to the saline injection, although such reactions are rare. Follow-up evaluations may be scheduled based on the findings of the flow study, particularly if any abnormalities were detected that require further investigation or intervention.