A bladder scan is a valuable tool used in healthcare to assess bladder function. It offers a non-invasive way to measure the volume of urine within the bladder, providing immediate insights for healthcare professionals. This procedure is generally painless and quick, making it a preferred method for evaluating bladder health.
What is a Bladder Scan?
A bladder scan utilizes ultrasound technology to measure the volume of urine in the bladder. This portable, non-invasive device emits high-frequency sound waves that travel through the body. When these sound waves encounter the bladder, they reflect, or echo, back to the scanner’s probe. The device then processes these echoes to create an image of the bladder and calculate its volume, typically displayed in milliliters (mL).
Unlike more invasive procedures like catheterization, a bladder scan avoids discomfort and the risk of infection, making it a safer and patient-friendly option. The immediate results displayed on the scanner’s screen provide real-time data about bladder fullness.
When a Bladder Scan is Performed
Bladder scans are performed in various clinical situations to evaluate bladder function. They assess for urinary retention, a condition where a person cannot completely empty their bladder, often due to an enlarged prostate, bladder outlet obstruction, neurological disorders, or certain medications.
Scans also measure post-void residual (PVR) volume, which is the amount of urine remaining in the bladder after a person has attempted to void. Measuring PVR helps determine if the bladder is emptying effectively, indicating incomplete emptying from issues like detrusor muscle weakness or neurogenic bladder dysfunction.
Bladder scans can also help decide if catheterization is necessary, reducing unnecessary invasive procedures and urinary tract infection risks. They also monitor bladder function in individuals with neurological conditions like Parkinson’s disease, stroke, or diabetes, identifying delayed bladder emptying which could lead to kidney complications.
Preparing for the Scan
The patient should lie in a supine position, flat on their back, which can be made more comfortable by bending their knees to relax the abdominal muscles. It is important to expose the lower abdomen from the navel to the pubic bone by adjusting clothing. Maintaining patient privacy throughout this process is also an important consideration.
For the device, the probe of the bladder scanner needs to be clean before use. A crucial step involves applying a generous amount of water-based ultrasound gel to the patient’s lower abdomen, specifically above the pubic bone. This gel is essential as it eliminates air pockets between the probe and the skin, allowing sound waves to transmit effectively and ensuring clear images and accurate volume calculations. Without sufficient gel, the sound waves may not travel properly, leading to inaccurate readings.
Operating the Bladder Scanner
Begin by turning on the device. Once the scanner is powered on, enter the patient’s relevant data, such as gender, into the system; this setting is important for precise results as the device’s algorithms adjust based on anatomical differences.
With the patient prepared and gel applied, place the probe on the lower abdomen, about 3-5 cm above the pubic bone, along the midline. The probe’s indicator should point towards the patient’s head. Gently angle the probe slightly downwards into the pelvic cavity to ensure the sound waves reach the bladder and bypass the pubic bone, which can obstruct the view.
Press the scan button on the probe to initiate the pre-scan, which helps locate the bladder on the screen. Slowly rotate and tilt the probe to center the bladder image, aiming for the largest and clearest view possible. Once an optimal image of the bladder is achieved, press the scan button again to complete the measurement. The scanner will then analyze the data and display the urine volume, often with an audible beep to indicate completion. After the scan, wipe off the ultrasound gel from the patient and probe.
Understanding the Results
Interpreting the volume readings from a bladder scan requires considering the patient’s specific circumstances and clinical context. The primary output is the estimated urine volume in milliliters. For post-void residual (PVR) measurements, a volume less than 50 mL is generally considered normal in healthy adults, indicating efficient bladder emptying. In individuals over 65, a PVR of less than 100 mL may still be considered acceptable. Volumes between 100-200 mL may suggest incomplete bladder emptying, while readings consistently above 200 mL, particularly over 300-400 mL, often indicate urinary retention.
Several factors can influence the accuracy of bladder scan results. Patient anatomy, such as obesity or the presence of gas in the bowel, can sometimes interfere with the sound waves, potentially leading to less accurate readings. Proper scanning technique, including correct probe placement and angling, is also crucial for obtaining reliable measurements. While bladder scanners provide immediate quantitative data, these results should always be interpreted by a healthcare professional, alongside the patient’s medical history and current symptoms. This comprehensive approach ensures appropriate diagnosis and management of any underlying conditions affecting bladder function.