Pushing flush too slow?

Nurses Medications

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So the other night I was trying to flush a patients iv that had NS @75. I was giving morphine. So I flushed a little, gave the morphine slowly, then went to flush and was push/pausing it but it stopped flushing. It was fine and then all the sudden wouldn't push. I didn't move the iv, pushed the morphine slow like you're supposed to, and it just wouldn't flush. Then it started swelling up. It had infiltrated but I'm just wondering what I did wrong. The iv was obviously in before I gave the morphine but then it blew after I gave it. Some nurse told me I could have pushed it too slow. She said u can push it too fast and too slow but I don't understand. Can anyone explain this and what I did wrong?

One other thing that is helpful with those delicate sites is using a smaller syringe to flush with. For example, if you have a size 24g on a thumb or pinky, sometimes the pressure from the 10cc flush syringe is too much. I don't know if your hospital uses them or not, but there is a smaller prefilled saline syringe (3 & 5cc), or simply extract the saline into a smaller syringe from the larger one.

Unless I'm mistaken, smaller syringes generate higher injection pressure than larger syringes do.

OP, I've never heard that pushing too slow can blow a vein/cause infiltration. It just sounds like the patient had fragile veins and that it was bound to happen sooner or later.

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Unless I'm mistaken, smaller syringes generate higher injection pressure than larger syringes do.

OP, I've never heard that pushing too slow can blow a vein/cause infiltration. It just sounds like the patient had fragile veins and that it was bound to happen sooner or later.

I would agree. Larger diameter syringes have less pressure than smaller diameter.

"PSI generated by a syringe is determined by 2 variables, the syringe diameter and the amount of force applied to the plunger rod. In general, the larger the diameter of the syringe barrel, the lower the PSI generated during flushing provided the force applied to the plunger is the same. For example, in an occluded catheter, 5lb. of force applied to the plunger of a traditional 3mL syringe will generate 55 PSI. The same 5lb of force applied to a 10mL diameter syringe generates 20 PSI. When aspirating, the converse is true. Larger diameter syringes draw greater vacuum than smaller diameter syringes."

http://www.bd.com/posiflush/support/

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And it's not about the "size" of the syringe, it's about the diameter (area, actually) of the plunger.

For a given force, the smaller the area, the greater the pressure.

OP, I am going to assert that that nurse simply doesn't know what she's taking about.

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And it's not about the "size" of the syringe, it's about the diameter (area, actually) of the plunger.

For a given force, the smaller the area, the greater the pressure.

Absolutely. I was being sloppy/lazy in how I worded my reply simply because all 20 cc syringes I've used had a larger diameter than the 1cc ones :) but I could have been more clear. Anyway, it's definitely force/area.

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When aspirating for example 1 cc the same amount of negative pressure is created with a 1cc syringe as with a 20 cc syringe. However, you can only pull back the plunger so far on the 1 cc syringe. That's the reason that you can create a larger negative pressure with the 20 cc syringe, the 1 cc reaches it's capacity at a lower volume (naturally).

The negative pressure correlates with the number of cubic centimeters aspirated.

(The pressure generated inside the syringe isn't linear, but parabolic. It increases rapidly for the first 10 cc or so, then it increases more slowly and finally plateaus).

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Specializes in Med/Surg, LTACH, LTC, Home Health.

Guys, I've been able to flush IVs very easily using a smaller-sized syringe even when I couldn't even move the plunger with the 10cc syringe. That was my actual experience, one that I've resorted to many times during my 28 years of experience. I didn't say it would work in every case, but that it was a suggestion. Some of you are so quick to knock other's suggestions.

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Specializes in Med/Surg, LTACH, LTC, Home Health.

I, not once said, it was factual or an absolute, but it is something that was shown to me years ago and is something to try.

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Guys, I've been able to flush IVs very easily using a smaller-sized syringe even when I couldn't even move the plunger with the 10cc syringe. That was my actual experience, one that I've resorted to many times during my 28 years of experience. I didn't say it would work in every case, but that it was a suggestion. Some of you are so quick to knock other's suggestions.

You may well have had success with using the smaller diameter syringes (perhaps because they generate a higher pressure). The only thing I commented on is that it's inaccurate to say that it generates less pressure than the larger diameter syringe.

I think that it's important that one is aware that one is applying a higher pressure to the catheter, since that can sometimes cause it to rupture/cause damage to the vein.

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Ya I know. I didn't start that one actually. We had tried everywhere and finally s nurse just went there

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Hmm I'll ask my coworkers about this one. I've never heard that. Thanks for the response

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Specializes in Med/Surg, LTACH, LTC, Home Health.

Well, the less pressure is what I was told when this was shown to me a long time ago. If, it is inaccurate or not, so be it. I'm not a chemist and I passed on what I was told. Facts are disproven all the time. This is why I passed it along as a suggestion. I really don't care about how it works, as long as it does. I believe there are a lot of nurses who know what works without knowing how it works in every situation. There are so many people on these boards who have absolutely NOTHING to say until they see a way to disagree with others. I made a suggestion about what has worked in my experience. Now, it the technicalities of what I said bothers you or anyone else, that's not my problem.

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Specializes in Emergency/Cath Lab.

The ONLY time you can flush too slow is with Adenosine.

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Specializes in Peds/Neo CCT,Flight, ER, Hem/Onc.
Guys, I've been able to flush IVs very easily using a smaller-sized syringe even when I couldn't even move the plunger with the 10cc syringe. That was my actual experience, one that I've resorted to many times during my 28 years of experience. I didn't say it would work in every case, but that it was a suggestion. Some of you are so quick to knock other's suggestions.

Nobody was "knocking" your suggestion just the reasoning behind it. It's important for folks to know that smaller syringes actually have higher pressures so that they understand the reason behind never using anything smaller than a 10ml syringe on sensitive lines. I'm sorry somebody misinformed you early in your career. Every poster who disagreed with you did it professionally and without personal attacks. Maybe if you tried to look at is as an educational opportunity you would take it far less personally. Nobody expects you to be a physicist but understanding the hows and why we do things is certainly important.

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