Tuesday, April 23, 2013

What The World Needs Now .... is Codes, Sweet Codes, It's The Only Thing Theres Just Too Little Of........

This is without a doubt my favorite ICD-9 codes. Imagine the granularity of clinical description possible with the additional codes that will be found in ICD-10!

""ICD-10-CM codes are the ones designated for use in documenting diagnoses. They are 3-7 characters in length and total 68,000, while ICD-9-CM diagnosis codes are 3-5 digits in length and number over 14,000. The ICD-10-PCS are the procedure codes and they are alphanumeric, 7 characters in length, and total approximately 87,000, while ICD-9-CM procedure codes are only 3-4 numbers in length and total approximately 4,000 codes.""

As it is the numbers and complexity of codes seen with ICD beggars the imagination. Furthermore, the use of those codes is by necessity rudimentary and poorly descriptive of the actual events surrounding the patient's hospital or clinical course. The time pressures of clinical practice often result in the practitioner using the 1st plausable code for the clinical scenario rather than the best or most descriptive for the scenario.

In the final analysis the reality of clinical work is that creating is a more intellectually gratifying and intrinsically more rapid process than choosing. WIth respect to a previous post in which I mentioned the supercomputer Watson, analysis of free text by such an artificial intelligence will come much closer to mirroring the reality of clinical work than trying to train the practitioner in the nuances of translation of clinical thought into structured data. Ultimately as so famously captured in the quote from Alfred Korzybski, 'The Map is not the territory.'

Friday, April 5, 2013

Fellow: n. A Trainee MD who does the same research as his attending MD when he was a fellow, but got the opposite, ergo, publishable result.

Marik, Flemmer, et al. The risk of catheter-related bloodstream infection with femoral venous catheters as compared to subclavian and internal jugular venous catheters: A systematic review of the literature and meta-analysis. Crit Care Med. 2012 Aug;40(8):2479-85.

Comments posted to EMCrit Blog concerning the meta-analysis above.

Forgive the short autobiographical comments, but designed to provide some 'cred' within the Emcrit community. I started my medical career as a Vietnam-era Special Forces & Ranger Medical Specialist, and our principal crash resuscitation access technique of those years were emergency surgical cutdowns. I am currently an Interventional/Invasive Cardiologist of 20(+) years practice, a Boarded and practicing Intensivist of 24(+) years practice, and a practicing Emergency Medicine Physician with over 29,000 hours of ED practice of which 75% was logged while a military physician, including a combat tour as the Chief of Emergency Medicine in a Combat Support Hospital.

Given my cardiology practice, the scope of which includes Cardiac Device Implantation (pacers and ICD's) as well as diagnostic and interventional right and left heart catheterizations, my ICU practice which includes about 40% sepsis/septic shock patients, and my ED practice, I conservatively estimate I have accessed the central venous system (External Jugular, internal jugular, infraclavicular subclavian, supraclavicular subclavian, extra-thoracic axillary vein, fermoral venous, external iliac vein to common iliac vein (used for cardiac device implantation due to bilateral subclavian and axillary vein stenosis) in over 20,000 unique patients.

The EmCrit community conversation on this topic while excellent has features which replicate intellectually the lethal knife-gun debate in the Magnificant Seven (see my blog page to re-visit this scene if not recalled or never seen before (http://statisticalmedievalist.blogspot.com/).

In any case, the points I want to make are that extolling a single access methodology as the sole-source solution to a clinical problem is naive and as my daddy used to tell me, 'use the right tool for the job, don't use a single tool for all jobs.'

As I know the community understands, the U/S guided IJ cannulation technique while a great advance has predictable issues with emergency line placement :
1. It adds a non trivial time extension to the procedure.
2. It entails significant risk of inadvertent carotid artery puncture in the patient who is under volume resuscitated with poor venous distention even in the setting of extreme Trendelenburg position when the vein lies directly overlying the carotid artery through the arteries course through the sternocleidomastoid triangle.
3. In the setting of known coagulopathy the IJ route is poorly compressible, and I have seen at least 3 patients develop airway compromise from neck hematoma.
4. Patient cooperation during a 'crash' vascular access situation, especially with a marginal airway can be dangerously compromising once the drape goes over the patient's head.
5. If CP arrest should ensue during preparation for the line, or worse during the line attempt, placing the line while attempting to maintain cardio-cerebral perfusion with good quality CPR is in my view a crap shoot worthy of your favorite Las Vegas Casino.
6. Pain inputs from neck vein placement and subclavian vein placement far exceeds that occurring from an expertly done femoral line.
7.EZ- I/O route while technically simple, fails to address the issues associated with requirements for high volume infusion in adults, multiple access requirements driven by IV drip incompatibilities, physical stability of line access during nursing care or transport positioning of the patient.
8. Femoral dialysis catheters in my experience clearly outperform IJ catheters with respect to predictability of the adequacy of the 1st dialysis run, i.e., they have a lower fiddle factor than the IJ route, and as your readers may know the SC dialysis route is complicated at least 25% of the time with SC vein stenosis.
9. I have experienced several cases of aeroembolism using IJ and SC routes in patients with high TV, high frequency respiration in spite of Trendelenburg positions (the position itself often precipitates or aggravates the situation it is trying to mitigate, the risk of devastating massive aero-embolism is nearly totally absent in the femoral route.

While my own practice mirrors that of some of your contributors, i.e., emergency placement of the femoral line with prompt removal after the patient is stabilized and transition to a SC line or PICC line, there have been significant numbers of patients who required long term femoral line placement due to abnormal venous occlusive disease (such as SVC syndrome) or long standing chronic venous thrombotic disease that I was unable technically or due to severe renal dysfunction unwilling to attempt to reconstruct with cath revascularization techniques, or they had persistant coagulopathy again making neck and chest wall access unduly hazardous. I have never personally seen a line infection in these patients with prolonged femoral access driven by these unique clinical considerations. Certainly I have seen more SBE related to PICC line use than I have ever seen with central line placements, with many of those lines dating to an era when the PICC routes were yet to be under the operational control of the hospital nursing PICC teams.

The reality is that line selection is a complex clinical judgement resistant to a 'one size fits all' strategy. It is driven by setting (level of hemodynamic instability, risks for abrupt 'crash'), patient factors (anxiety, cooperativeness, sedation levels or safety for sedation, airway sustainability/adequacy/patency), operator experience and flexibility, and probable need for multiple drug infusions and therapies or likelihoood for emergency temporary dialysis support.  

I am not surprised that this meta-analytic literature review maps to my clinical instincts concerning the femoral access route. It is a welcome addition to my armamentarium since many non-clinicians (who ironically now 'grade us' for our core measure report cards) are doctrinaire and insensitive to the true and necessary complexity of line site selection.

In summary, limiting yourself to a single tool, single access strategy is short sighted and can potentially result in your loss of a salvageable patient if you had more than one or tools in your toolbox.

Thursday, April 4, 2013

Figure - Ground Dichotomy - Is It The Essence of Clinical Expertise?

The essence of the clinical art is perfection in diagnosis. The solution to most problems becomes relatively simple once the diagnosis is established. The role of modern informational tools in the practice of medicine should be to provide immediate  expert level advice and reference to the the best  therapies. This has been in fact the major use of medical information technologies over my own career, the use of so-called knowledge retrieval tools. Long before, UpToDate became a daily used tool, the StatRef CD collection followed me everywhere and to everywhere.

However, the art of diagnosis remains the extraction of pattern from a background of noise and distraction. Perhaps the 'smartest' Internist who ever helped train me in Residency was  simultaneously the worst diagnostician I have ever worked with. His approach to solving a clinical problem was too simply assign all pieces of data as equally probable, i.e., equally likely and equally important, generate a set of exhaustive lists of differential diagnosis, based on each 'fact' and than try to cross correlate his diagnostic logic within this context. In fact the approach was the epitome of the method of exhaustion, it exhausted his house staff, his patient, and ultimately exhausted the 'bank.'

As our figure/ground illustration demonstrates, a change in perspective, a 'fresh way' to see the data is often illuminating. My own approach to a difficult diagnosis revolves around identifying what I consider to be the 'organizing principle' of the case. That is I consciously look for how this case is unlike other cases I have seen, so that I might focus on what is unique in the case presentation. So, rather than rejecting a fact, observation, or measurement, especially if it is a 'fact' of high emotional significance to the patient, I embrace that case feature, as the basis for developing an explanatory pathophysiological mechanism for the patient's symptoms. This is contrary I believe to the usual clinical impulse driven by the 'need for speed' to prune the potential problem states by ignoring what is not recognized or what is felt idiosyncratic to the patient.

The difference in emphasis is profound and the result in my experience superior to the physician driven shot-gun review of systems approach, felt so essential to a complete history. Heretically I embrace the comment made in The House of God, articulated by the FatMan, "What did you ever learn from a ROS?" Elucidating an appropriate history should naturally result in the characterization of the pertinent negatives and positives associated with that patient's presentation during a naturalistic discussion with the patient. However, 'counting' the pieces of a review of systems is simple to do, and simplistic to do, and allows to outside reviewers the illusion that they can determine the quality of the data acquisition by the simple act of counting symptoms replied to in the negative or the affirmative.

However, the memory of my own undergraduate training in mathematics often whispers to me silently in the night..... 'elegance', i.e., brevity and relevancy of the fact set, is more profound and a more certain demonstrative of true art. Given two valid formal proofs of any mathematical proposition, the shortest proof is the superior proof.

So in a real and profound sense, the data set which supports a diagnosis that is the smallest such set, shows the greatest mastery of the clinical art. Because a computerized record of a clinical encounter is voluminous and 'complete' does not make it necessarily correct, appropriate, or even easily digestible.

The discussion ultimately focuses on a recurring theme for this blog, preserving the passion of the art of medicine, when the weight of all forces being brought to bear on the practice of medicine relate to cost control via hidden resource rationing. Furthermore, confusing counting with review, volume with quality, and substituting exhaustive exploration for true knowledge all muddies the waters and allows for the discussion of quality in medical care to become ultimately the comparison of isolated snippets of clinical care provider Vs provider, hospital Vs hospital in what will surly be exercises in superior marketing rather than the pursuit of superior care.

Thursday, March 28, 2013

Elementary, My Dear Watson, Elementary..... or is it?

IBM's Watson—the same machine that beat Ken Jennings at Jeopardy—is now churning through case histories at Memorial Sloan-Kettering, learning to make diagnoses and treatment recommendations. This is one in a series of developments suggesting that technology may be about to disrupt health care in the same way it has disrupted so many other industries. Are doctors necessary? Just how far might the automation of medicine go?

(The Atlantic March 2013). 

The genesis of many of the efforts in medical informatics over the 30(+) years of development have centered on the grandiose efforts to model and then replace the practical intelligence of the physician with automated logic. Most recognized of these efforts is probably Mycin the rule-based expert system developed by Dr. Edward Shortliffe as his PhD project in the early 1970's. However, as revolutionary as the rule-based inference engine that was at the core of the development of mycin, and as widespread as that engine subsequently became as the reasoning core for expert system 'shells', most notably KEE (Knowledge Engineering Environment) it was never implemented in a clinically meaningful form. 

Now enters Watson, the winner of the renowned Jeopardy match of the century... a truly impressive tool that is able to digest 60 million pages of text per second, being engineered to enhance the clinical decision making of mere humans, by assuring that they are aware of all the ground breaking 'research' within the field of their practice. In the Atlantic article cited above, the author breathlessly elaborates a clinical scenario in which the human oncologist did not test the patient for the KRAS variant of pulmonary adenocarcinoma and in fact Watson recognized this fact and made such a recommendation.

Let me quote in full from the article:
"Harley lukov didn’t need a miracle. He just needed the right diagnosis. Lukov, a 62-year-old from central New Jersey, had stopped smoking 10 years earlier—fulfilling a promise he’d made to his daughter, after she gave birth to his first grandchild. But decades of cigarettes had taken their toll. Lukov had adenocarcinoma, a common cancer of the lung, and it had spread to his liver. The oncologist ordered a biopsy, testing a surgically removed sample of the tumor to search for particular “driver” mutations. A driver mutation is a specific genetic defect that causes cells to reproduce uncontrollably, interfering with bodily functions and devouring organs. Think of an on/off switch stuck in the “on” direction. With lung cancer, doctors typically test for mutations called EGFR and ALK, in part because those two respond well to specially targeted treatments. But the tests are a long shot: although EGFR and ALK are the two driver mutations doctors typically see with lung cancer, even they are relatively uncommon. When Lukov’s cancer tested negative for both, the oncologist prepared to start a standard chemotherapy regimen—even though it meant the side effects would be worse and the prospects of success slimmer than might be expected using a targeted agent.
But Lukov’s true medical condition wasn’t quite so grim. The tumor did have a driver—a third mutation few oncologists test for in this type of case. It’s called KRAS. Researchers have known about KRAS for a long time, but only recently have they realized that it can be the driver mutation in metastatic lung cancer—and that, in those cases, it responds to the same drugs that turn it off in other tumors. A doctor familiar with both Lukov’s specific medical history and the very latest research might know to make the connection—to add one more biomarker test, for KRAS, and then to find a clinical trial testing the efficacy of KRAS treatments on lung cancer. But the national treatment guidelines for lung cancer don’t recommend such action, and few physicians, however conscientious, would think to do these things."

Now lets ignore several things here, i.e., that pulmonary adenocarcinoma is equally likely to affect non-smokers as smokers, i.e., it is not related to the 'risk factor' of tobacco ingestion, that national guidelines for treatment are national guidelines related to the 'best evidence' related to that illness at the time of their development, that the belief that enrollment in an oncological trial means a superior result than conventional therapy is naive, flawed, and demonstrates a gross misunderstanding of the process of clinical trial research. Given all these caveats I am less than impressed with the performance of Watson in this particular case. Specifically, in the case of advanced metastatic cancer of any cause, enrollment and personal outcome in a clinical trial is completely dependent on not only the 'right diagnosis' but also in the luck associated with contributing to the right clinical trial and being lucky enough to be in the right arm of that study. 

What seems to be at play here, is we are asking the wrong question or using the tool in the wrong way. Given the power of the instrument, rather than attempting to unsuccessfully compete as a clinical expert, instead providing real time cost effective support for the housekeeping chores increasingly required of practitioners seems the more useful way to use this type of computing power. How cheaply could Watson function as a natural language translator of dictation and documentation or machine powered accurate diagnosis coding?  Not sexy, not 'cutting edge' but in a health care system dominated by a 33% 'admins-trivia' carrying cost, i.e., 1/3 of all health care expenses are spent on the administration of the system rather than in direct patient care - how profound could the cost savings accrue if we could automate the non-clinical value added activities of coding and transcription and documentation of care?

In my ideal world, all clinical encounters would be videotaped and anyone interested in anything other than the summarization of the clinical encounter by the clinical expert could review the taped encounter for whatever picayune requirement that 3rd party might attempt to impose for their unique administrative requirements. Watson could make an immediate and real impact on clinical care, however, such transparent facilitation of the care of existing providers has a much lower priority than the 'pie in the sky' attempts to capture and emulate clinical expertise by machine driven approaches, an approach and goal that has  littered and corrupted the entire field of medical informatics from its earliest days. 

Tuesday, January 15, 2013

It takes two to Tango, two to 'toast' the planet, but three to safeguard the patient.

At the height of the cold war, as well as today, two USAF Missile Officers can launch a missile resulting in a world-wide conflagration.

Imagine my surprise when I learned that one of the hospitals at which I work couldn't give tPA without three persons meeting in time and space to agree on the dose and the identity of the patient being treated with the drug.

The frustration of this situation was a 32-year old male, four weeks out from a ORIF (operative reduction and fixation) to the right lower leg, who presented to my ED with collapse, shock, syncope, and chest pain and dyspnea. A point of care echocardiogram demonstrated within one minute of his arrival in the trauma bay, acute RV pressure overload establishing the diagnosis of life threatening pulmonary embolism.

Of patient's who die of pulmonary embolism, 70% die within the 1st hour of their event. (Sadeghi, et al. Acute Massive Pulmonary Embolism: Role of the Cardiac Surgeon. Tex Heart Inst J, V32(3);2005, 430-433). Because of the massive investments in time, interest, concern and good process engineering an acute ST segment myocardial infarctions patient on their worst day will face an overall mortality rate of no more than 4-5%. The less frequent but highly lethal pulmonary embolism patient faces an overall mortality of at least 33-40% with their first episode of pulmonary embolism.

So my patient with an extreme risk of 1-hour death from his pulmonary embolism did not receive his thrombolytic drug therapy ordered by me within the 1st 5 minutes of his ED arrival until almost 1 hour and 45 minutes after his ED arrival. How was this possible?

The hospital had targeted tPA as a high risk medication and invoked safeguards to ensure its appropriate use. Therefore, byzantine processes have been implemented in order to make sure the medication is used appropriately and safely. However, the unintended consequence of this policy was to make timely administration of the medication almost impossible. As an example of the height of the ridiculousness of the process was the local requirement for three individuals, 2 independent nurses and the pharmacist to consensually agree to patient, dose of the drug, and appropriateness of the indication for the drug.

What sense is there in me having the ability to almost instantaneously make this diagnosis, if processes are put in place frustrating timely lifesaving therapy? As is too common in the patient safety area, draconian recommendations occur based on someones well intentioned idea(s) about what enhances safety without consideration of the potential downsides to the proposed policy, and without even fundamental or rudimentary studies done to demonstrate  the actual effectiveness of the 'policy.'

Again, my point is not to argue against the wisdom of the patient safety movement, but rather to argue for intelligent and thoughtful design of safety processes to ensure that safety is enhanced but that timely therapy is not compromised.