Fuel Injection Death
mary Zeman via Melissa Bryan posted about an accident where a student nurse in training (3rd day on the job) administered a feeding bag of coffee and milk instead of a unit of blood. http://goo.gl/otI4e For starters, I don’t think coffee mixed with milk looks like a unit of blood. Nevertheless, in Mary’s post I explained what I think likely happened, e.g., COD.
Nutritional specialist Dr. Armando Carreir told the network that Ribeiro’s death “would have been as if [she] was suffocating.” from HuffPuff: http://goo.gl/euhoM
So how can the patient be suffocating? It was likely due to pulmonary edema (fluid in the lungs). So how did the patient get fluid in the lungs? Not knowing the exact mixture of coffee and milk, I’m guessing that the mixture was hypertonic. Let me back up and talk briefly about intravenous (IV) pharmaceuticals.
When you adminster a large volume of fluids IV, it has to be at physiologic pH (7.4), isotonic, and iso-oncotic. There are cases where you can give a fluid that is not one of these three properties to correct for the patients condition.
Tonicity
From the Wiki:
Tonicity is a measure of the osmotic pressure gradient (as defined by the water potential of the two solutions) of two solutions separated by a semipermeable membrane. It is commonly used when describing the response of cells immersed in an external solution. Like osmotic pressure, tonicity is influenced only by solutes that cannot cross the membrane, as only these exert an osmotic pressure. Solutes able to freely cross the membrane do not affect tonicity because they will always be in equal concentrations on both sides of the membrane.
There are three classifications of tonicity that one solution can have relative to another. The three are hypertonic, hypotonic, and isotonic. There’s a good figure in the Wiki that shows what happens to the blood cells in the three types of tonicity.
http://en.wikipedia.org/wiki/Isotonicity#Isotonicity
Colloid osmotic pressure (COP) or Oncotic pressure
COP is an osmotic pressure caused by protiens in the vasculature which opposes the hydrostatic pressure. The normal COP of plasma is between 20-25 tor. An increase in COP above normal levels will lead to water leaving the interstitium and entering the vascular space. http://en.wikipedia.org/wiki/Oncotic_pressure
Here’s a great guide on IV fluids for nurses: http://goo.gl/bilmc
Image Source: http://goo.gl/jrwtK
#ScienceEveryday when it isn’t #ScienceSunday
October 25, 2012
This is a rather depressingly fascinating case.
October 25, 2012
I’m baffled that it could happen.
October 25, 2012
I’m going to claim ignorance on the whole feeding bag of coffee and milk mixture (those really exist?), but wouldn’t they be stored in an entirely different location from the blood? Also, as you mentioned, those two things look entirely different.
October 25, 2012
I’m assuming someone left the feeding back next to the patient and was going to give it later. The student nurse probably mixed up patients and/or assignments.
Again, I have no idea how you mix those two up.
October 25, 2012
From the link I pasted in the other post [ http://tinyurl.com/9gtpeuq ]:
Fantastico [Brasilian TV news program]: Are you aware of the risk of injecting intravenously what should be oral feeding?
Rejane [R. Telles, the intern studying to be a nurse technician]: I am.
Fantastico: Did you know the risk that existed from injecting in the wrong place?
Rejane: I did, but since it was in the same place, anyone can get confused.
(Translation is mine, I know Portuguese, but I’m not a professional translator, nor have even interned as one for three days 🙂
Apparently even she had no idea how both get mixed up. I couldn’t play the video on that link, no idea if it shows both types of bags side by side. What a baffling case.
I shall remember not to joke about wanting an IV drip of coffee (and if I ever do then I’ll be sure to mention that it should be isotonic, pH balanced and iso-oncotic).
Thanks for the explanation Chad Haney, I had no idea about teh concept of Oncotic Pressure.
October 25, 2012
In the U.S., for medical error prevention and systems engineering control purposes, blood products are not stored in bags that are shaped like crystalloid/colloid solutions or feeding bags (and they are clearly labeled in large letters).
Typically, before they even start, there is a protocol to double-check that the name and birthdate on the bag matches the patient.
Additionally, most hospitals (in the U.S.) have a policy of continuous observation of the patient over the first 15 minutes or so (with intermittent monitoring thereafter) to check for adverse transfusion reactions, which aren’t uncommon. The initial infusion rate is extremely slow and only advanced after the caregiver is sure the patient can tolerate it. Otherwise, the infusion is stopped immediately at the first sign of problems.
Even if the nursing student (who should have been supervised) hung the wrong bag, I personally feel like several additional blatant mistakes had to happen for this to go completely unnoticed.
I’m assuming the patient was a frail 80-year-old (as most hospitalized elderly patients are). A unit of pRBCs (often approx. 250-300 mL) is usually administered over 1.5 to 4 hours via infusion pump, depending on the patient’s cardiac, pulmonary, and renal function (4 hours is typically the longest time frame since there is an increased risk of bacterial contamination after that). Of note, if the infusion rate is too fast, volume overload itself can cause congestive heart failure and pulmonary edema, especially in a patient with a predisposing condition. It doesn’t necessarily even have to be a hypertonic solution (of course that would definitely make it worse).
October 25, 2012
And on a (morbidly) conceptually-related side note regarding solution tonicity and asphyxiation, postmortem forensic analysis of lung tissue can reveal whether someone drowned in freshwater or saltwater (if that matters to the case as far as the crime’s location or method).
October 25, 2012
Thank Fernando J. Rodriguez for the added info and your translatio efforst.
Thanks Johnathan Chung for your insight as to what happens in American hospitals. I did not mention these factors, including each blood unit has a unique bar code, because the incident happened in Brazil. I have no idea what safety measures (or lack thereof) are in place in Brazil.
October 25, 2012
As a retired nurse who once administered blood transfusions many times daily, I can say a error of this magnitude is incomprehensible and outrageous. There are so many checks and double checks in place when blood is given, not only to make sure the patient is given the blood set up for her, but also that the blood is the correct type (A, B, AB, O, positive, negative), for the patient, and that there are no reactions, etc. Our protocol was for two nurses to verify the blood typing, patient, chart number, transfusion number, etc, at every step, including at the bedside. Really sad outcome.
October 25, 2012
Mara Rose it seems that such level of control and cautionary measures have not been implemented in Brasil
Here’s a short news item (in Portuguese) suggesting that lack of funding for staff and overcrowded conditions on the hospital were a factor allowing this to happen.
http://g1.globo.com/bom-dia-brasil/noticia/2012/10/rj-posto-onde-idosa-recebeu-cafe-com-leite-na-veia-tem-irregularidades.html
An interview with the nursing student that injected the coffee in the old lady’s vein has her mentioning that the supervising nurse refused to go and help the two interns and instead was playing on her cellphone.
http://tinyurl.com/9gtpeuq
These are the same links I had already posted in Mary Zeman’s post, BTW.