Is it more difficult to get blood from a stone or urine from a 3-month-old infant with a fever for which there is no apparent cause? Silly question? Not if you’re a pediatrician, and it’s 4:30 on a Friday afternoon before a 3-day holiday weekend.
You would probably prefer your chances with the stone. You have been there before. You have been peed on more than once by a 3-month-old baby you were examining. But you know from experience that when you really need just a milliliter or two of urine from a sick infant to rule out a diagnosis, those few drops of golden liquid will be hard to come by.
What are your options? You can reexamine the infant and hope that her tympanic membranes that looked so normal 20 minutes ago have now become red, opaque, and bulging. Or maybe you will hear a few crackles in her chest that you didn’t hear on first listen. Any hint of a diagnosis other than a urinary tract infection could make the results of a urine sample moot.
But of course the child’s exam hasn’t changed, and you can’t convince yourself that your training can be ignored. You must have that urine. Can you bring yourself to launch an invasive attack on the child with a catheter? Despite your reassurances and explanations and your confidence with the technique, catheterization isn’t easy with the child’s parents watching. You wonder again, “Do I really need that urine?” You have done one or two needle bladder aspirations during your training years ago, but that prospect has even less appeal than the catheterization. Of course, there is always the urine bag and its significant risk of providing you with a contaminated sample or leaking even if it has been properly applied.
If only the patient were old enough to follow directions and give you a clean catch midstream sample. But you have chosen to be a pediatrician, and with that comes the reality that most of your sick young patients with unexplained fevers aren’t going to be able to comply by producing a urine sample. Sometimes you get lucky, and as the child is being prepped for catheterization or application of the collecting bag, she will surprise you by squirting out a small arc of urine that can be caught in midair – that is, if you or your assistant is prepared with an open sterile (or even just clean) cup and quick hands. After several missed opportunities over the first several years in practice, I have tried to remember to always have my assistants ready with an open container. And remind them to keep their eyes on the exposed perineum of any infant from whom we might need a clean urine sample.
But there is another option, and you can find it in this September’s Pediatrics ( Evaluation of a New Strategy for Clean-Catch Urine in Infants, Labrosse et al. 2016 Sept;138[3]). The Canadian investigators describe a technique in which the infant is stimulated to void. After giving the child 20 minutes to drink and gently cleaning the perineum, the child is held vertically, the girls with their hips flexed. The physician or nurse then taps the suprapubic area at a rate of 100 taps per minute for 30 seconds and then gently massages the lumbar paravertebral area for 30 seconds. The two stimulation maneuvers are then alternated until the child voids. The investigators recommend stopping if no urine is obtained in 300 seconds, or 5 minutes.
The results are very encouraging with a success rate of 49% on a series of 126 infants. The investigators report a contamination rate of 16% that is not statistically different from collections using an invasive technique. Median time to success was 45 seconds.
You can look at the photos for yourself, but it looks like you would need at least one assistant in addition to a parent who is holding the child. I suspect that it also helps to have quick hands once the voiding starts.
It certainly sounds like a technique worth trying. The authors claim that when used as the first attempt at collection, the number of catheterizations could be cut by a third. I suspect that just like with any technique, some folks on your staff will emerge as the ones with the magic hands and might have a success rate well above that reported in this article. Groom and treasure those in-house experts at collecting those little yellow drops. They are worth their weight in gold.
Dr. Wilkoff practiced primary care pediatrics in Brunswick, Maine, for nearly 40 years. He has authored several books on behavioral pediatrics including “How to Say No to Your Toddler.” Email him at pdnews@frontlinemedcom.com.
