Interestingly a study found the using the veinviewer actually reduced the rates of first cannulation success in experienced pediatric nurses (http://www.ncbi.nlm.nih.gov/pubmed/23492965). The relative risk was 0.76 (ci 0.63-0.91) so they were about 25% less likely to get it first time when using the system. The trial was stopped early due to the results and potential harm to patients due to extra sticks.
Maybe it is just the distraction of having something new in front of them? Maybe there is an unconscious correction that experienced nurses make that is reduced by having the vasculature presented on the skin? Possibly (although unlikely) an issue with the visualization algorithm? Maybe it is something to do with kids? I haven't seen the system so can't really comment, interesting though, I just assumed that it would be better.
Thanks for the link, Josh. I'll bet the operative word in the unexpected outcome was that these were "experienced" nurses. The apparatus would presumably be more useful for novices or less experienced staff.
Yes I wondered the same thing, although it is interesting that using the system significantly degraded the performance of the experienced nurses, rather than just not improving it. Sort of implies that there is some correction that experienced nurses are making that is interrupted, maybe with extra time they would merge the correction with the visualization and improve above baseline.
A more pessimistic view might be that learning while using this technology you may never develop the correction factor (what ever it maybe) and rely on the visual overlay more heavily. This effect would actually be disguised as the use of the system would presumable improve performance from really bad (as they are starting from scratch) to the degraded performance shown in the trial of about 50% success. An improvement over starting out but not as good as the experienced nurses who trained without it.
I just went and had a look at the article and there were a few interesting additional details. The nurses where part of the 'Intravenous Access Team' so are likely to be exceptionally good even by the standards of experienced nurses. It also mentions that they all used the veinviewer system at least 20 times before the first use in the trial, which should reduce the effect of it simply being new technology. In addition the patients were referred onto the team if the were a difficult cannulation and were only selected to be included if there were no visible veins. From the article "The potential study patients were examined by members of the Access Team and if no veins were visible on any of the upper and lower extremities in ambient light, they were included in the study.". To my mind that changes the picture a bit as this system was under-performing in a situation which should have been optimal for it.
True. One wonders whether there are some inherent problems in aligning the projection system, since at that age range (to age "0") there would be little margin for error if the image was laterally displaced by a couple mm.
I work for a competitor of Veinviewer so take this with the appropriate grains of salt. The Veinviewer product does have potential problems with alignment. They all require a periodic calibration check (with an undefined period). The unit used in the study was an early generation and is pretty challenging to position over kids and infants. One of the claims to fame of the AccuVein is that it is handheld so it is easier to use for assessing the patient for the best vein.
More generally the trend in the studies after this one have been to the positive. Based in part on this trend, the Infusion Nurses Society has started recommending vein visualization as part of the IV standard of care. The INS is made up of nurses that would be core members of an Access Team.
I really could have used one of these when I was working in ICUs!
ReplyDeletethis is nice, but there is a better vein visualization product on the market called VeinViewer
ReplyDeleteBetter how?
ReplyDeleteInterestingly a study found the using the veinviewer actually reduced the rates of first cannulation success in experienced pediatric nurses (http://www.ncbi.nlm.nih.gov/pubmed/23492965). The relative risk was 0.76 (ci 0.63-0.91) so they were about 25% less likely to get it first time when using the system. The trial was stopped early due to the results and potential harm to patients due to extra sticks.
ReplyDeleteMaybe it is just the distraction of having something new in front of them? Maybe there is an unconscious correction that experienced nurses make that is reduced by having the vasculature presented on the skin? Possibly (although unlikely) an issue with the visualization algorithm? Maybe it is something to do with kids? I haven't seen the system so can't really comment, interesting though, I just assumed that it would be better.
Josh
Thanks for the link, Josh. I'll bet the operative word in the unexpected outcome was that these were "experienced" nurses. The apparatus would presumably be more useful for novices or less experienced staff.
DeleteYes I wondered the same thing, although it is interesting that using the system significantly degraded the performance of the experienced nurses, rather than just not improving it. Sort of implies that there is some correction that experienced nurses are making that is interrupted, maybe with extra time they would merge the correction with the visualization and improve above baseline.
DeleteA more pessimistic view might be that learning while using this technology you may never develop the correction factor (what ever it maybe) and rely on the visual overlay more heavily. This effect would actually be disguised as the use of the system would presumable improve performance from really bad (as they are starting from scratch) to the degraded performance shown in the trial of about 50% success. An improvement over starting out but not as good as the experienced nurses who trained without it.
I just went and had a look at the article and there were a few interesting additional details. The nurses where part of the 'Intravenous Access Team' so are likely to be exceptionally good even by the standards of experienced nurses. It also mentions that they all used the veinviewer system at least 20 times before the first use in the trial, which should reduce the effect of it simply being new technology. In addition the patients were referred onto the team if the were a difficult cannulation and were only selected to be included if there were no visible veins. From the article "The potential study patients were examined by members of the Access Team and if no veins were visible on any of the upper and lower extremities in ambient light, they were included in the study.". To my mind that changes the picture a bit as this system was under-performing in a situation which should have been optimal for it.
True. One wonders whether there are some inherent problems in aligning the projection system, since at that age range (to age "0") there would be little margin for error if the image was laterally displaced by a couple mm.
DeleteI work for a competitor of Veinviewer so take this with the appropriate grains of salt. The Veinviewer product does have potential problems with alignment. They all require a periodic calibration check (with an undefined period). The unit used in the study was an early generation and is pretty challenging to position over kids and infants. One of the claims to fame of the AccuVein is that it is handheld so it is easier to use for assessing the patient for the best vein.
DeleteMore generally the trend in the studies after this one have been to the positive. Based in part on this trend, the Infusion Nurses Society has started recommending vein visualization as part of the IV standard of care. The INS is made up of nurses that would be core members of an Access Team.