Selective Digestive Decontamination (SDD) – The ICU Book

Lately I’ve been reading The ICU Book by Paul L. Marino.  Everyone in crticial care recommmends this book as standard reading for interns and junior residents, and I have to say it has been quite the read so far.

One of the articles in Marino’s book that has really stuck out to me has to do with selective digestive decontamination (SDD). Marino explains that in the presence of severe chronic illness, the G.I. tract becomes populated with more pathogenic organisms capable of causing invasive infections. He quotes one study that showed that hospitalized patients are often colonized with pathogenic organisms in the G.I. tract most notably aerobic gram-negative bacilli like Pseudomonas. This paper noted that the change in microflora is not environmentally driven, however it is directly related to the severity of illness in ICU patients. Marino recommends selective digestive decontamination for all ICU patients.

One example of this regimen includes a three-step decontamination process.

1. Oral cavity: a paste containing 2% polymyxin, 2% tobramycin, and 2% amphotericin to be applied inside the mouth with a gloved finger every 6 hours.

2. G.I. tract: 10 ml solution containing 100 mg polymyxin, 80 mg tobramycin, and 500 mg amphotericin and given via nasogastric tube every 6 hours.

3. Systemic: intravenous cefuroxime, 1.5 g given every 8 hours for the 1st 4 days of this therapy

Multiple years of randomized controlled trials have shown that ICU acquired infections are dramatically reduced with this kind of regimen. In one study that Marino quotes all 3 types of infections common in ICUs–pneumonia, urinary tract infections, and septicemia septicemia from vascular catheters–were significantly less frequent in patients who received selective digestive decontamination. Many clinical trials are showing a combined 40% relative reduction in the frequency of acquired infections in the ICU.

Marino mentions that over 20 years of experience with selective digestive decontamination and numerous reports of its efficacy clearly show the benefits related to selective digestive decontamination. However there continues to be a debate over the merits of this practice. Marino states two concerns that feed this debate. First the impact of SDD on mortality and also the possibility of the emergence of antibiotic resistant organisms. Marino points out that studies that support the relative reduction in mortality in ICU patients that have received selective digestive decontamination and also he points to studies that show no evidence of antibiotic resistance with use of a standard selective digestive decontamination regimen.

So the question is why don’t hospitals use this regimen in the ICU? I cannot speak for all hospitals, however I can speak for the UC Health. In our ICU we do not use a selective digestive decontamination regimen. I’ve questioned the fellows about this practice, and I usually receive an answer dealing with the concern of the emergence of antibiotic resistant organisms. When I explained that this was a huge part of Dr. Marino’s ICU book the fellows question the studies stating that most of these are over 10 years old. This prompted me to look again at the current data to see if SDD is still the huge benefit that Dr. Marino felt that it once was.

I found an article in the Expert Opinion of Pharmacotherapy, a metanalysis from this year which included 65 randomized controlled trials with over 15,000 enrolled patients, over a 25 year period.  This article concluded:

From an objective, and strictly evidence-based, perspective we conclude that SDD is recommended because there is level 1 evidence to support its use. Moreover, intensivists should be aware that SDD is a life-saving strategy: only 18 patients need to receive the full protocol of SDD to save one life. This makes the ethics of withholding SDD highly questionable.

This was incredibly shocking to me, because I felt that I have stumbled upon something in medicine with evidence so clear and for such a long term period that there seems to be absolutely no debate in the clinical literature.  With evidence this clear and strong, why isn’t SDD a routine in ICUs across the country? Are physicians really that set in their ways?

 

References:

Marino, Paul L. The ICU Book. 2007. Third Ed. Chapter 4 pg 63-80.

Silvestri L, van Saene HK, Petros AJ. Selective digestive tract decontamination in critically ill patients. Expert Opin Pharmacother. 2012 Jun;13(8):1113-29. Epub 2012 Apr 25.

Medical Students Have To Learn Sometime

[The dude in this picture is just a random guy I googled, not the real patient talked about in this post]

Another medical student and I were hanging around the emergency room at a small town hospital the other day.  The weather had been particularly nice that day and a man decided to fix some of the gutters and siding on his home.  So he climbed up his ladder and started working, but his guardian angel must have taken a coffee break and his ladder broke.  The man fell 15 or so feet down to the concrete, and was transported by ambulance to the ER.

Unfortunately this man had a large laceration across his forehead, and another long his arm.  Lucky for us medical students, this man had two large lacerations that required stitches.  For story completeness – this guy was completely stable and had absolutely no life-threatening injuries.  The lacerations were the only injuries he sustained as a result of his fall.

The doctor working in the ER with us decided this was a great opportunity for us to practice our suturing skills, and so the doctor told the other medical student and I to come over “and assist him with stitching up.”  The man’s wife did not like the sound of that at all, and she asked if the students would be allowed to put in the actual stitches.  The doctor told her that we would, under his close supervision.  The wife wasn’t convinced that this would be ok.  So she asked if there was ANY way that the doctor could call in another physician to help “assist” with the stitches.  He said that the other doctors were too busy to be called in for this, and the medical students were available and have had plenty of training in this type of procedure.  The man’s wife told the doctor that she really didn’t want students practicing on her husband, and the doctor reassured her that we have had lots of training and that medical students can do this.

It felt weird to be in the middle of that disagreement.  On the one hand, I completely understand the wife’s concern of having medical students essentially “practice” on her husband.  Yes we’ve had 6 years of post high school training, but in all honesty probably less than 5 hours of suture only training at this point.  But on the other hand, us medical students need to practice on someone.  If you only had the most experienced people do the job every time, then how would you train the next generation?  Also, if I completely mess up and a suture falls out, then we can always put another in or just let it heal without the missing stitch.  It won’t make a big difference.  I also understand that the wife may not have known that this was a fairly low risk procedure on the grand scale of things, and so I can understand where she’s coming from.

Yes we have to learn sometime.  If everyone says no to medical students, then there will never be an experienced group of physicians.

Deep Brain Stimulation & The Age of the Brain

Deep brain stimulation (DBS) is a surgical procedure in which an electrode is inserted into a certain part of the brain to send electrical impulses to the nerves.  Currently, it’s an accepted practice (FDA approved) for the treatment of Parkinson’s, essential tremor, and dystonia patients.  But I believe this is just the beginning of what we are going to see for indications of DBS.


Currently, there is studies looking at whether DBS can be used in patients with depression (Jiménez, Fiacro et al.) or even addiction (Vassoler et al.). This is huge. This means that in the near future, we could have a surgical treatments for a bunch of brain pathologies that are currently extremely difficult to treat. Just think about it, treatment for drug resistant depression, bipolar, addiction, seizures, Tourette syndrome, obsessive-compulsive disorder, phantom limb pains, Lesch-Nyhan syndrome, psychosis, and others. This is a gigantic step in the right direction for neurosurgery, neurology, and psychiatry in the ultimate pursuit in understanding how the brain works.  


Now obviously a surgical procedure for these disorders and syndromes is not the ideal situation since any surgery carries inherent risks.  But hopefully the research and understanding that comes from studying patients who undergo DBS for treatment will lead to a better understanding of all of these brain pathologies, and take us down the road to the future of neurological treatment.  


I think it is these DBS patients and studies that will help us unravel some of the mysteries of the brain, and I really look forward to it.  I think this point in history is the “Age of the Brain.”


Jimenez F, Velasco F, Salin-Pascual R, Hernandez JA, Velasco M, Criales JL, et al: A patient with a resistant major depres- sion disorder treated with deep brain stimulation in the infe- rior thalamic peduncle. Neurosurgery 57:585–593, 2005

Fair M. Vassoler, Heath D. Schmidt, Mary E. Gerard, Katie R. Famous, Domenic A. Ciraulo, Conan Kornetsky, Clifford M. Knapp, and R. Christopher Pierce : Deep Brain Stimulation of the Nucleus Accumbens Shell Attenuates Cocaine Priming-Induced Reinstatement of Drug Seeking in Rats. The Journal of Neuroscience, August 27, 2008. 28(35):8735– 8739 8735