From Myron Yaster MD before reading today’s reader and PAAD executive council responses, I’ve got a wonderful announcement. As of this morning we now have over 7,000 subscribers!
From Mark Schreiner MD (retired) in response to Bob Spear’s comments on measles
I have another perspective related to Bob Spear’s comments regarding vaccination. Yes the death rate from COVID is low - not zero - for young children. But children are remarkably effective in spreading disease. What about their parents, grandparents, teachers and other adults that children will come in contact with? One of my daughters has an autoimmune disease courtesy of Covid and she is a bit terrified of getting a serious viral infection.
Vaccinating children to protect others has a long history. Rubella is an inconsequential infection in children. They receive the vaccine to prevent pregnant women from passing it to their fetus and giving rise to birth defects. We all have some obligations due to others and not just to ourselves.
From Myron Yaster MD
In the PAAD: Central arterial catheter placement in children: When it may be worth the risk (April 28, 2025), and in the PAAD Remembering the Classics: Safety When Flushing Radial Arterial Lines (April 30, 2025) I raised many questions about the possible risks of retrograde cerebral embolization for a catheter so close to the aortic arch and in how these catheters are flushed, regardless of where they are placed. I asked several members of the PAAD’s executive council to weigh in as well as our readers to offer recommendations on how to best flush an arterial line catheter. Much to my surprise/shock/dismay there was no consensus on a process that takes place daily in the ORs and ICUs. Here are some of the responses
Allison Ross MD
Making a recommendation is tricky based on what is out there as it is not clear and has several contributing factors. I surprisingly recall being in training (thank you, Hopkins) and being told clearly that no larger than a 3 ml syringe should be used to flush a baby/infant arterial line, and to never use the pressure bag. Once I left training, I saw that 10 ml syringes and pressure bags were used by nearly every other pediatric anesthesia provider.
Based on the referenced study, if you were looking for a recommendation and the average was 6.6 mLs in adults (assuming this is around 0.1 mL/kg or less), perhaps flushing no more than 0.1 mL/kg in a child (which is conveniently also the same volume of air that can result in a clinically significant venous air embolus) with a controlled pressure would be reasonable. However, this is a guess at best and not based on any evidence. Further, this is a recommendation based on weight rather than height and does not take into consideration the pressure of injection. This would be a worthy, and I think relatively easy, research study to perform. So, in summary, I’ve got nothing.
Alan Jay Schwartz MD MSEd
Myron raises an important question and Allison you have responded with logic that we don't have enough information to make a RECOMMENDATION about flushing technique. I agree with an exception. Allison noted the caution to not use a syringe with more than a 3 mL volume and not to use pressure systems/bags to flush. I agree and suggest we could/should be more specific in the following way. I always taught that the flush syringe be placed with the plunger/syringe barrel positioned up so that any residual air bubble would rise to a location most distant from the patient/luer connection to the line being flushed. That position needs to be coupled with the strict recommendation that the syringe NEVER be emptied during the flush so as to avoid flushing that little bit of air that is ALWAYS in the syringe, into the vessel (artery and/or vein). I also think that a 1 mL syringe is also problematic as its volume is so little that that residual air bubble has a better chance of being flushed into the patient. I think it is also worth stressing that the principle of holding the syringe barrel up and never emptying the syringe applies to medication administration as well as line flushing. While my comments above may seem simplistic, they will minimize "sloppiness" when flushing and administering medication adding a safeguard for our patients. Obviously, attention to such detail is a better way to assure practitioner finesse and safety for our patients. As PAAD has a worldwide audience and the case may be that some locations do not consider this type of finesse, I believe that PAAD is an important vehicle to "spread the word" on even the little things that can/will provide a positive difference.
Genie Heitmiller MD
We trialed filters for the peripheral arterial lines at one point (and they might still be used in the ICU), but we still needed to be vigilant for any visible bubbles, clots, or debris in the lines. For that matter, we had to be vigilant in watching ALL the lines (venous and arterial) for cardiac patients, since they often all dumped into that darn single ventricle. We ended up not using the filters - but maybe they are used now? I wonder if others are using them? Filters were always used in the CPB circuit.
Justin L. Lockman MD MSEd
As Gleich pointed out in his Mayo study, the incidence of complications from any arterial line is very low. Thus, the primary question in my mind is this: with all this evidence of retrograde flow by imaging modalities, why aren’t we seeing cerebrovascular injuries all the time? Hard to make an argument for changing practice to fix a problem that doesn’t exist. Or are they happening and we’re not seeing them/detecting them? I think we need more data before making any practice change recommendations.
Lynn Martin MD MBA
The only additional comment I would add is to standardize your practice. There is currently no clear best practice, so pick one and study and understand its strengths and weaknesses. Then spread this information and mitigate when possible. Reducing variation always increases familiarity, reliability and safety.
James DiNardo MD
I use the A-line only for blood gas samples (ACTs or other labs can be drawn from the CVL). I draw the arterial sample at a site as close as possible to the patient and the line is “cleared” with a gentle slow hand flush using the minimal volume necessary to clear the line. I would never draw blood all the way back to the transducer as it contaminates the transducer with blood and requires an enormous volume to clear.
From Ethan L Sanford, MD, ECMO Medical Director, Assistant Professor of Pediatric Anesthesiology and Pediatric Critical Care Medicine, UT Southwestern and Children's Medical Center, Dallas, TX
As a resident, I was trained to use a 10cc syringe to pull the waste fluid/blood, use a separate syringe to draw the lab, then reapply the 10cc waste syringe to flush blood back through the artery, change the stop-cock position to pull flush into the 10cc syringe and flush the line in intermittent small amounts over ~10-20 seconds (I admit this rate and volume of flushes is highly variable).
I don't do or advocate this approach now. Instead, I either just discard the minimal waste blood for older kids or give back through an IV for babies for whom the waste might be an issue. I then hand-flush the arterial line with a 10cc syringe in small, interval amounts (again, variable amounts and rate).
I sometimes wonder if we should simply apply low dose heparin at low rates continuously and not flush the line. My ECMO specialists are horrified by the PICU and anesthesia flushing of arterial lines. The concern would be for clot formation, but I don't know if this has ever been analyzed. In our PICU, vamps are utilized which decrease waste and syringe exposure but are a pain in the ass and still carry risk of air bubbles/embolism.
From Shawn Jackson MD PhD
We run our hep saline on a syringe pump running at 2-3 mL/hr. My current practice (especially in the ICU) is to bolus 1-2 mL "off the pump" while pulling the tab on the transducer. It takes about 15 seconds which is painfully slow in the moment but reduces my fear about embolization.