Do You Ever Aspirate Urine?

In this back to the basics episode, Dr. Christopher Beck interviews Dr. Aaron Fritts about his standard procedure for nephrostomy tube placement, preferred tools, and troubleshooting tips.

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SHOW NOTES

Dr. Fritts says that most of his referrals come from urology, and patients need treatment for hydronephrosis, kidney stones, and pre-operative access for lithotripsy. He goes over his workup, which can be expedited in emergency cases. He checks for normal coagulation tests and anticoagulation medications, since bleeding is the most common and dangerous complication of the procedure. Both doctors prefer to use CT imaging to map out the procedure, identify stone burden, and decide which calyx to access. It is important to use CT to make note of and avoid the colon (lateral) and paraspinal muscles (medial) when choosing an access site. Dr. Fritts also marks the access site before the patient gets prepped for the procedure, in order to ensure that the correct area is cleaned. Patients are usually under moderate sedation with versed and fentanyl.

Then the doctors walk through a typical nephrostomy tube placement under ultrasound guidance. They emphasize that lidocaine needs to be injected all the way down to the cortex to maximize patient comfort and decrease the likelihood of patient movement during the procedure. Then, the needle is inserted into a calyx. While it is standard to access the lower pole to minimize bleeding risk, Dr. Beck sometimes prefers mid-pole access since this provides a shorter distance from skin to target and a more favorable angle to enter the ureter from the renal pelvis. The upper pole is generally avoided due to risk of diaphragmatic puncture, but it can be accessed if a stone is present there. Dr. Beck shares a tip about injecting saline to plump up the calyces and allow for better access.

Dr. Fritts describes the two-stick technique that was primarily used before ultrasound access was available. He also recommends communicating with urologists in lithotripsy patients to identify optimal access sites for each patient’s lithotripsy. If the wire is placed directly on top of the stone and you have difficulty maneuvering the wire around the stone, you can inject saline to dilate the system and obtain a better angle for the wire.

Finally, the doctors talk about drain selection, which is usually an 8Fr or 10Fr. The drain is secured with stitches, and possibly a bumper stitch. Pyonephrosis patients are usually kept inpatient, while other patients can get discharged after two hours. It is important to watch for hematuria and distinguish between mildly red venous blood from minor procedural trauma (which will subside) and bright red blood from arterial damage.

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RESOURCES

SIR Now:

https://sirnow.sirweb.org/

Ep. 97- Nephrostomy Tube Placement with Dr. David Feld:

https://www.backtable.com/shows/vi/podcasts/97/nephrostomy-tube-placement-basic-to-advanced

Diuretic agent and normal saline infusion technique for ultrasound-guided percutaneous nephrostomies in nondilated pelvicaliceal systems:

https://pubmed.ncbi.nlm.nih.gov/22893420/

Bumper Stitch for Drainage Tube Securement:

https://www.jvir.org/article/S1051-0443(11)01353-4/pdf