I worked in a biomedical equipment service department for a large university hospital, where a new building had just been finished, and all nursing units were moved in. Shortly after the move, our central sterile processing department started sending us IV pumps that were returned from new nursing units because of discharged backup batteries. The batteries are normally only used during patient transports or power outages. The standard nursing practice was to keep devices with rechargeable batteries plugged in while in use or in storage.
At first it was just a couple pumps a week from one model of a manufacturer’s pump. All of the returned pumps did indeed have depleted batteries. When we tested the charge/discharge characteristics of the sealed lead-acid batteries in the returned pumps, they indicated normal operation of the charging circuits and normal battery run times. The pump manufacturer did not have any suggestions beyond what we had tried.
As a precaution, we replaced the batteries and the pumps and returned them to service. We kept an eye out for these particular pumps, but other pumps with discharged batteries started showing up, and were not coming from the same serial numbers. Pretty soon, a variety of IV and syringe pumps from different manufacturers started coming in with the same problem. We compared our service records with central sterile processing’s equipment assignment records. Those records indicated almost all problem pumps were returned from the new neonatal Intensive Care Unit.
Since this was a new building, we now suspected that there might be outlets that were intermittent or not powered. Again, we coordinated problem pumps with bed assignment histories. We checked all the outlets but found no anomalies. We even installed a power line monitor on suspected locations, but to no avail. Nothing connected the dots. We asked the nursing staff to immediately report any questionable pump battery failures to us, so we could do an onsite investigation.
With a report of another pump battery failure, I had a facilities electrician accompany me to the patient room. The pump was indeed in “low battery” mode, even though it was plugged into an outlet. While standing around rehashing possible failure scenarios, the electrician noticed that the plug of the offending pump was plugged into the power outlet at a slight upward angle. I reached up about six feet and reseated the plug, with some difficulty, into the outlet. The pump immediately went into the “battery charging” mode.
The problem? The hospital had new “hospital-grade” outlets with very strong contact retention-force that required more than normal pressure to insert the power plugs. If the plugs were not inserted far enough, any movement of the cord could eventually cause loss of contact and force the pumps into an unintended “battery mode.”
This entry was submitted by Ken Moffett and edited by Rob Spiegel.
Ken Moffett holds a BS in industrial arts education from Iowa State University. He is currently employed as a scientific instrumentation technician for the science division at Macalester College in St Paul, Minn.
Tell us your experience in solving a knotty engineering problem. Send stories to Rob Spiegel for Sherlock Ohms.
So what evidence do you have that those remedial classes are for public school students only. I teach in a private high school, which my parents could never have afforded to send me to, and I run into some of the same unmotivated brick heads I met when I was student teaching in one of the more well-to-do suburban high schools in this area. I am at an all male school and the students all come to us from private grade schools. Some come literate and well prepared, but others arrive through the back door because their father is Doctor whosawhatsis, or attorney ambulance chaser and they contribute large sums of money. One of our faculty has several degrees from Harvard, but he was fired because he could neither teach nor control his classes.
Point being, incompetance is no more exclusive to the public school systems than excellence is confined to Ivy League schools. We also have to teach remedial classes because some students think, "u r rite," is acceptable English. I challenge you to enroll in any 101 level class in any university you choose and pick out those students came to that campus via a public school system.
Really? When many of the beginning college courses revolve around remedial english and math before today's students are capable of beginning real college classes? I think it IS the problem. And there is a lot of evidence that it is. Snarky? Probably. The truth? Surely.
I seriously doubt that all of the nurses, the installing electricians, the contractor's purchasing agent and the designing archetect were the products of Public Education. That sort of snarkey comment adds little to the discussion and nothing towards solving the problem at hand.
Thanks! It seems to be working well in our application....the plugs cost a few $ more, but much easier than explaining why a critical piece of portable battery powered equipment was dead when you really needed it!
The architectural design problem was not forseeing the possibility of having the need for more low level outlets than is normally needed in an NICU. This unit had come from an old building where outlet strips (cringe!) were a necessity. Our hospital pushed the technical limits on keeping these premies alive.
It has been my experience that outlet orientation (ground "U" pin up or down) is usually an indication that the outlet was installed by a union or non-union electrician. The "code" seems to vary in different cities across the US, though.
Good point, Kf2qd. The plugs themselves may not have been the problem, but rather it was where they were mounted on the wall. Even so, it would have been wise to have an indicator showing whether the batteries were charging or not.
This is a case of poor architectural design. If he had to reach up over 6Ft to push teh plug, how was that little nurse supposed to ever push the plug in? Hospital Grade plugs have a much higher gripping pressure on teh contacts and are very difficult to plug in as well as to pull out. If a short nurse was trying to plug them in, at near full extension of her reach, at which point she had very little mechanical force to impart to the plug.
Receps were mounted too high, poor ergonamic design.
Yes, Jmiller, a charging light would likely cost very little. For a specialized system in a medical facility, the small cost would offer clear benefits.
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