ditch doctor
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56 year old man is recovering from surgery that repaired bilateral femur fractures sustained in a MVC. Surgery was uneventful and deemed as success. On the 6th post-op day the patient is having respiratory difficulty, pleuritic chest pain and a productive cough of clear secretions with bright red streaks. Vitals are BP:95/55, P:96, RR: 26, T: 100.3 F, sPO2: 97% on 4LPM nasal cannula. PE: unremarkable except for mild to moderate respiratory distress. Surgical wounds are unremarkable. Blood gasses are pH: 7.48; PO2: 82; PCO2: 34; HCO3: 24. CXR is unremarkable. Your next step in management of this patient should be:
A. Nuclear scintigraphic ventilation-perfusion scan (V/Q scan)
B. Contrast Pulmonary Angiography
C. Contrast enhanced multidetector CT scan (MDCTS)
D. Transesophageal ultrasound
E. Electrocardiogram (EKG)
F. MRI of the thorax
G. Blood cultures then empiric antibiotics
H. Urinalysis
I. Panic
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| AAAAA
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A
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| docofthebigapple
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Answer is A
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| MAZI
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i think that because of unstable hemodynamic the next and best step is thrombolitic therapy
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| ditch doctor
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C- according to several sources.
This is the reason I made this question up. You don't think such an easy question would come without a catch, did you? Most of our study guides say VQ is the first thing we should do-- it's almost a knee jerk reaction. However, according to several peer-reviewed sources, C would actually be the correct answer. CT technology has come to the point where it is preferred over the VQ scan and might even replace Angiography as the gold standard. I don't know. I hate when I find conflicting information. Anyone read PIOPED II?
Check these out:
http://www.emedicine.com/EMERG/topic490.htm under Imaging Studies
http://www.fpnotebook.com/LUN46.htm under Step 5
http://en.wikipedia.org/wiki/Pulmonary_embolism
What does everyone think? Where does one go for a definitive answer when sources conflict?
Edited by ditch doctor on 07/10/06 - 10:50 AM
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| MAZI
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MAZI wrote:
i think that because of unstable hemodynamic the next and best step is embolectomy
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| ditch doctor
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MAZI wrote:
i think that because of unstable hemodynamic the next and best step is thrombolitic therapy
BP is > 90 systolic
Pulse is only 94
Sats are > 95%
Respirations are only 26
Physical Exam shows only Mild/Moderate SOB
Blood gasses are only mildly derranged.
Is that unstable? Everything is borderline normal or only slightly derranged. I wouldn't think so. I mean, I'm not going to sit around and watch Scrubs in the lounge waiting for the nurse to page me, but I'm not going to wake the attending... not, yet anyway.
Either way, it's not one of the answer choices. The real question is who/what do we consult when there is differences of opinion in peer reviewed material?
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| AAAAA
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ditch doctor wrote:C- according to several sources. This is the reason I made this question up. You don't think such an easy question would come without a catch, did you? Most of our study guides say VQ is the first thing we should do-- it's almost a knee jerk reaction. However, according to several peer-reviewed sources, C would actually be the correct answer. CT technology has come to the point where it is preferred over the VQ scan and might even replace Angiography as the gold standard. I don't know. I hate when I find conflicting information. Anyone read PIOPED II? Check these out: http://www.emedicine.com/EMERG/topic490.htm under Imaging Studies http://www.fpnotebook.com/LUN46.htm under Step 5 http://en.wikipedia.org/wiki/Pulmonary_embolism What does everyone think? Where does one go for a definitive answer when sources conflict?
The answer is still A but in real life, you also do spiral CT scan !
USMLE will never , never, never, never, never tell you to order a CT scan !
Why? It is too expensive for a spiral CT scan !
Always do simple things, this is the rule and is not a knee jerk reaction.
You can read about all the CT scan stuff but examination means simple procedure comes first !
Case closed !
The answer is A ! A A A A A !
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| AAAAA
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This is the reason I made this question up.
Don't make up question and answer because there are rules and regulations of the USMLE
The answer is A
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| AAAAA
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What does everyone think? Where does one go for a definitive answer when sources conflict?
Wrong, there will always be conflicting answers.
That's why 15% of all questions in USMLE are experimental and will be used in next year until the dust is settled.
The answer is A from USMLE !!
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| AAAAA
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ditch doctor wrote:C- according to several sources. This is the reason I made this question up. You don't think such an easy question would come without a catch, did you? Most of our study guides say VQ is the first thing we should do-- it's almost a knee jerk reaction. However, according to several peer-reviewed sources, C would actually be the correct answer. CT technology has come to the point where it is preferred over the VQ scan and might even replace Angiography as the gold standard. I don't know. I hate when I find conflicting information. Anyone read PIOPED II? Check these out: http://www.emedicine.com/EMERG/topic490.htm under Imaging Studies http://www.fpnotebook.com/LUN46.htm under Step 5 http://en.wikipedia.org/wiki/Pulmonary_embolism What does everyone think? Where does one go for a definitive answer when sources conflict?
Confirming pulmonary embolism
The gold standard for diagnosing pulmonary embolism (PE) is pulmonary angiography. In most cases, however, when PE is suspected on the basis of shortness of breath and chest pain, the following studies may confirm the presence of an embolus. Pulmonary angiography is used less often because of wider acceptance of CT scans, which are non-invasive.
Computed tomography with radiocontrast, effectively a pulmonary angiogram imaged by CT, is increasingly used as the mainstay in diagnosis. Advantages are clinical equivalence, better access for patients and the possibility of picking up other lung disorders from the differential diagnosis in case there is no pulmonary embolism.
Ventilation-perfusion scan (or V/Q scan), which shows that some areas of the lung are being ventilated but not perfused with blood (due to obstruction by a clot). It is a type of scintigraphy. This study is used less often because of CT technology, however, it may be useful in patients who have an allergy to iodinated contrast
Clearly, spiral CT is recommended in tertiary centers and in many research medical centers and is emerging as the tool because it is less invasive but very expensive.
In examination, the V/Q scan is still the answer so A is right !
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| AAAAA
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Spiral CT scans can identify lung lesions less than one centimeter in size. ... cost of saving one life using a single CT scan could be as low as $2500.
US $2,500.00 per scan !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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| AAAAA
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Or as high as US $3,500-$4,000.00 !!!!!!!!!!
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| AAAAA
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Why answer A is correct :
Please read the article:
Use of Spiral CT Angiogram to Replace Ventilation-Perfusion Scan or Pulmonary Angiogram in Strategies for the Diagnosis of Pulmonary Embolism: A Cost-Effectiveness Analysis
Rodney W Smith and Hyungjin Myra Kim
St. Joseph Mercy Hospital: Ann Arbor, MI, University of Michigan: Ann Arbor, MI
ABSTRACT
Background: Prior cost-effectiveness analyses (CEA) using spiral CT angiogram (CTA) for the diagnosis of pulmonary embolism (PE) have used high sensitivities of CTA and have not used clinical probability of PE in the analysis. Objective: To determine if CTA can replace ventilation-perfusion scan (VQ) or pulmonary angiogram (PA) for the diagnosis of PE. Methods: A decision-analysis model was constructed to compare various validated strategies for PE diagnosis with similar strategies that replace PA with CTA, and with strategies using only d-dimer (DD), venous ultrasound (USN) and CTA. Mortality and cost at 3 months were estimated. Clinical probability was varied among low (3.2%; range 1%–10%), moderate (14.3%; range 10%–38%) and high (49%; range 38%–78%) prevalence of PE. Sensitivity of CTA was set at 70% (range 60%–99%) based on a prospective management study of ED patients evaluated for PE. Turbidimetric DD was used (sensitivity 0.98, specificity 0.43). One- and two-way sensitivity analysis was performed on uncertain variables in the model. Strategies were considered equally effective if mortality difference was <=0.5%. Results: Strategies using DD, USN and CTA without VQ were not cost effective at any clinical probability. At low clinical probability, no strategy with CTA is cost-effective compared with DD-VQ-USN. At moderate clinical probability, 2 strategies using CTA are cost-effective compared to a reference strategy of DD-VQ-USN-PA: DD-VQ-USN-CTA has equal efficacy and costs $601 less per patient, and VQ-USN-DD-CTA is equally effective and costs $466 less per patient. At high clinical probability, substituting CTA for PA in VQ-USN-PA is equally effective at $737 less per patient.
Conclusion: This CEA suggests that CTA cannot replace VQ scan in diagnostic strategies for PE. At low clinical probability, CTA strategies are not cost-effective, but at higher probability, CTA can replace PA in the diagnosis of PE. These strategies should be prospectively validated in clinical trials.
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| AAAAA
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Conclusion: This CEA suggests that CTA cannot replace VQ scan in diagnostic strategies for PE. At low clinical probability, CTA strategies are not cost-effective, but at higher probability, CTA can replace PA in the diagnosis of PE. These strategies should be prospectively validated in clinical trials
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| AAAAA
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ditch doctor wrote:C- according to several sources. This is the reason I made this question up. You don't think such an easy question would come without a catch, did you? Most of our study guides say VQ is the first thing we should do-- it's almost a knee jerk reaction. However, according to several peer-reviewed sources, C would actually be the correct answer. CT technology has come to the point where it is preferred over the VQ scan and might even replace Angiography as the gold standard. I don't know. I hate when I find conflicting information. Anyone read PIOPED II? Check these out: http://www.emedicine.com/EMERG/topic490.htm under Imaging Studies http://www.fpnotebook.com/LUN46.htm under Step 5 http://en.wikipedia.org/wiki/Pulmonary_embolism What does everyone think? Where does one go for a definitive answer when sources conflict?
Please make sure you read the real source before posting the correct answer which is A and not CT scan !
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| ditch doctor
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AAAAA wrote:
Don't make up question and answer because there are rules and regulations of the USMLE
Fear not, my friend, I have read the rules and regulations. They are about 40 or 50 pages, but half of it is just descriptions of question types. If you would like a copy, they are found easily on the internet with a bit of Google-ing They are a good read, because it helps you get understand where question writers are coming from.
They are not that hard to follow at all, I wish more professors would read them. Also, I have been writing undergraduate and graduate level exams for a while before I went back to medical school.
Making up your own questions and bouncing them off friends is a great study adjunct. Coming up with your own 3 and 4 step questions really helps you to understand any disease process better than simply studying. Synthesis is the highest form of learning and processing information. Memorization is the lowest.
Worried about a bad question? If you write a bad question and are proven wrong, it helps uncover weakenesses in your studies. If you know a question is wrong and do research to prove it wrong you learn material much better. Win-win scenario all the way around. Everyone should be making up 3-4 good quality questions each week while studying for any exam.
Edited by ditch doctor on 07/11/06 - 03:10 AM
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| ditch doctor
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AAAAA wrote:
USMLE will never , never, never, never, never tell you to order a CT scan !
Why? It is too expensive for a spiral CT scan !
Money is a double edged sword on the USMLE, you do try to save money, but at the same time you do not withhold better treatment/diagnostic modalities to cut costs.
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| ditch doctor
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AAAAA wrote:
The answer is A ! A A A A A !
I believe you, and on my exam I will choose A. This point of this is to discuss when you find well respected, peer reviewed conflicts. Some of the more notable examples are use of a paper bag in hyperventilation, salmonella being more common in sickle cell than Staph.
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| ditch doctor
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AAAAA wrote:
Conclusion: This CEA suggests that CTA cannot replace VQ scan in diagnostic strategies for PE. At low clinical probability, CTA strategies are not cost-effective, but at higher probability, CTA can replace PA in the diagnosis of PE. These strategies should be prospectively validated in clinical trials
Sigh, we can toss articles back and forth all day, this is not the point.
Spiral CT angiography for suspected pulmonary embolism: a cost-effectiveness analysis.
van Erkel AR, van Rossum AB, Bloem JL, Kievit J, Pattynama PM.
PURPOSE: To investigate the cost-effectiveness of diagnostic strategies involving spiral computed tomographic (CT) or conventional pulmonary angiography in the diagnosis of suspected pulmonary embolism. MATERIALS AND METHODS: A model was created for analyzing cost-effectiveness on the basis of available literature data. Diagnostic algorithms consisting of combinations of perfusion and ventilation scintigraphy, ultrasound, D-dimer assay, conventional angiography, and spiral CT angiography were compared. Preference for strategies was determined on the basis of the mortality and cost per life saved. RESULTS: For all realistic values of the pretest probability of pulmonary embolism and coexisting deep vein thrombosis and of the specificity of spiral CT angiography, all of the best strategies included spiral CT angiography. With an assumed sensitivity for spiral CT angiography of less than 85%, a conventional angiographic strategy yielded a lower mortality but did not yield superior cost-effectiveness. CONCLUSION: The use of spiral CT angiography is likely to reduce the mortality and improve cost-effectiveness in the diagnostic work-up of suspected pulmonary embolism.
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| ditch doctor
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AAAAA wrote:
Spiral CT scans can identify lung lesions less than one centimeter in size. ... cost of saving one life using a single CT scan could be as low as $2500.
US $2,500.00 per scan !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
My grandmother is worth *at least* 5 times as much!!!
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| ditch doctor
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AAAAA wrote:
Please make sure you read the real source before posting the correct answer which is A and not CT scan !
What is the real source? PIOPED II? Harrison's? Cecil's? eMedicine? Tintinalli? Kaplan notes? USMLE World or Qbank?
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| AAAAA
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Thank you, ditch doctor !
I am so glad someone finally responded to me after 6 months.
The answer is very simple. CTA CT angiogram are actually used to make other diagnosis but as regarded to P.E., the Board, NBME who runs the USMLE still prefers V/Q.
Once the American Thoracic Society and the National Institutes of Health decided a Natioanal Consenus and established national guidelines, then CT will be the answer !
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| AAAAA
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ditch doctor wrote:
What is the real source? PIOPED II? Harrison's? Cecil's? eMedicine? Tintinalli? Kaplan notes? USMLE World or Qbank?
The real source is national guidelines established by the AMerican Thoracic Society and the NIH.
ATS American Thoracic Society meets once a year and NIH National Lung and Heart and Blood may issue guidelines.
I am checking them out for you.
Review books are not dangerous but need a few books to compare than you get a favor !
Thank you Ditch doctor !
There are many, many, many countries use universal health care system instead of American fee-for-service. So those countries may not afford to order CT angio on every patient suspected of P.E.
This is just my point !
My family has real crisis and a liver transplantation is needed. But the Government may not want to do a transplantation on my family member because of cost ! $$$ Money is a factor in medicine, a big factor in controlling the cost of medicine.
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| AAAAA
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American Thoracic Society Develops Guidelines on Diagnosis of Venous Thromboembolism
SHARON SCOTT MOREY
The American Thoracic Society (ATS) has developed clinical practice guidelines for the diagnosis of acute venous thromboembolism. The guidelines were written by the ATS clinical practice committee and cover the diagnostic approach to acute deep venous thrombosis and to acute pulmonary embolism. The guidelines are published in the September 1999 issue of the American Journal of Respiratory and Critical Care Medicine. The document is available on the World Wide Web to subscribers of ATS journals online (http://www.atsjournals.org).
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