Hello all, guess where I am now?
I am here in Nairobi, Kenya to teach point-of-care ultrasound for Kenyan physicians. I am very excited and hope they like it.
Tuesday, February 18, 2020
Saturday, June 15, 2019
A Hunt for the Right Reference 2
I believe I have located the right reference. While I was reading another article, I have found the reference which looks almost alike, but not identical.
"Mahan G, Dabestani A, Gardin J, Allfie A, Burn C, Henry W (1983) Estimation of pulmonary artery pressure by pulsed Doppler echocardiography [abstr].Circulation [Suppl 3]68:367"
Look at the words "[abstr]" and "Suppl 3". So it is NOT an article, but an abstract, my friends. We should be able to find it in the supplemental edition of Circulation in 1983 but for sure I could not find it in Circulation 1983;68:367, since it does not exist.
Finally, I guess I have located the right reference, but I use the term "guess" since I have not confirmed this abstract in print. This supplement is unfortunately too old to locate in my university's library in Print, but I would pursue it anyway.
Now I feel better as I have found the "right" reference for the equation: mean PA = 79 - (0.45 x AT), but also am amazed to find this famous equation is based on an abstract, not even on an article which has been taught for many years in the guidelines, review course, and textbooks.
"Mahan G, Dabestani A, Gardin J, Allfie A, Burn C, Henry W (1983) Estimation of pulmonary artery pressure by pulsed Doppler echocardiography [abstr].Circulation [Suppl 3]68:367"
Look at the words "[abstr]" and "Suppl 3". So it is NOT an article, but an abstract, my friends. We should be able to find it in the supplemental edition of Circulation in 1983 but for sure I could not find it in Circulation 1983;68:367, since it does not exist.
Finally, I guess I have located the right reference, but I use the term "guess" since I have not confirmed this abstract in print. This supplement is unfortunately too old to locate in my university's library in Print, but I would pursue it anyway.
Now I feel better as I have found the "right" reference for the equation: mean PA = 79 - (0.45 x AT), but also am amazed to find this famous equation is based on an abstract, not even on an article which has been taught for many years in the guidelines, review course, and textbooks.
Friday, June 14, 2019
A Hunt for the Right Reference
I recently taught at Advanced Critical Care Echocardiography course at the CHEST headquarter in Glenview, IL when I realized this while reading a guideline from ASE.
This famous (?) equation of estimating mean pulmonary artery (PA) pressure by using pulmonary arterial acceleration time (AT) does not have the right reference:
mean PA pressure = 79 - (0.45 x AT)
Where is it from? This equation is based upon which article? Research? Well, when you read the guideline from the American Society of Echocardiography (ASE), the reference for this equation is written so clearly.
(Reference 81)
Mahan G, Dabestani A, Gardin J, Allfie A, Burn C, Henry W. Estimation of pulmonary artery pressure by pulsed Doppler echocardiography. Circulation 1983;68:367.
The problem is that I could not locate this article. There is no such article in Circulation 1983; 68:367. I know, I know, I did my homework. I went to the Circulation website, went to the past issues, went to the one published on August 1, 1983 Volume 68 Issue 2, and alas, there was no such article. One article ends on page 367, then the next one starts on page 368, neither of which carries this title nor the authors.
https://www.ahajournals.org/toc/circ/68/2
Maybe there might be typos, the year might be wrong, or pages might be wrong. I guess I should be able to find the right reference just googling the equation. After spending hours googling, I gave up. There is some web info about this equation, but no clear mentioning of the reference. Now what? Contact ASE, which I did. First by sending an email like below, then by calling them. Guess what, the staffs at ASE are so kind as to contact the writing group for the 2010 Right Heart guideline immediately upon my calling. Thank you so much. So, I guess I wait for their answer. Stay tuned.
My email to ASE
"While reading your guideline published in 2010 as below, I could not find the reference (81) as shown below.
Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, Solomon SD, Louie EK, Schiller NB. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr. 2010 Jul;23(7):685-713; quiz 786-8. doi:10.1016/j.echo.2010.05.010. PubMed PMID: 20620859.
(Reference 81)
Mahan G, Dabestani A, Gardin J, Allfie A, Burn C, HenryW. Estimation of pulmonary artery pressure by pulsed Doppler echocardiography. Circulation 1983;68:367.
I am afraid there might be an error. Kindly suggest me the right reference. Appreciate your inputs in advance."
This famous (?) equation of estimating mean pulmonary artery (PA) pressure by using pulmonary arterial acceleration time (AT) does not have the right reference:
mean PA pressure = 79 - (0.45 x AT)
Where is it from? This equation is based upon which article? Research? Well, when you read the guideline from the American Society of Echocardiography (ASE), the reference for this equation is written so clearly.
(Reference 81)
Mahan G, Dabestani A, Gardin J, Allfie A, Burn C, Henry W. Estimation of pulmonary artery pressure by pulsed Doppler echocardiography. Circulation 1983;68:367.
The problem is that I could not locate this article. There is no such article in Circulation 1983; 68:367. I know, I know, I did my homework. I went to the Circulation website, went to the past issues, went to the one published on August 1, 1983 Volume 68 Issue 2, and alas, there was no such article. One article ends on page 367, then the next one starts on page 368, neither of which carries this title nor the authors.
https://www.ahajournals.org/toc/circ/68/2
Maybe there might be typos, the year might be wrong, or pages might be wrong. I guess I should be able to find the right reference just googling the equation. After spending hours googling, I gave up. There is some web info about this equation, but no clear mentioning of the reference. Now what? Contact ASE, which I did. First by sending an email like below, then by calling them. Guess what, the staffs at ASE are so kind as to contact the writing group for the 2010 Right Heart guideline immediately upon my calling. Thank you so much. So, I guess I wait for their answer. Stay tuned.
My email to ASE
"While reading your guideline published in 2010 as below, I could not find the reference (81) as shown below.
Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, Solomon SD, Louie EK, Schiller NB. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr. 2010 Jul;23(7):685-713; quiz 786-8. doi:10.1016/j.echo.2010.05.010. PubMed PMID: 20620859.
(Reference 81)
Mahan G, Dabestani A, Gardin J, Allfie A, Burn C, HenryW. Estimation of pulmonary artery pressure by pulsed Doppler echocardiography. Circulation 1983;68:367.
I am afraid there might be an error. Kindly suggest me the right reference. Appreciate your inputs in advance."
Thursday, June 13, 2019
IVC and right atrial pressure
Another heated topic. Well, things seem to be clear. When you read the guideline, say the one from ASE in 2010 below, they are quite clear:
(1) IVC diameter is normal (<2.1 cm) and collapses >50% with a sniff: 3 mm Hg (0 - 5 mm Hg)
(2) IVC diameter is large (>2.1 cm) and collapses <50% with a sniff: 15 mm Hg (10-20 mm Hg)
(3) Either IVC diameter is normal (<2.1 cm) but collapses <50%, OR IVC diameter is large (>2.1 cm) but collapses >50%, 8 mm Hg (5-10 mm Hg)
Lang RM, Badano LP, Mor-Avi V, Afilalo J, Armstrong A, Ernande L, Flachskampf FA, Foster E, Goldstein SA, Kuznetsova T, Lancellotti P, Muraru D, Picard MH, Rietzschel ER, Rudski L, Spencer KT, Tsang W, Voigt JU. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015 Jan;28(1):1-39.e14. doi:10.1016/j.echo.2014.10.003. PubMed PMID: 25559473.
Questions
Which one could have higher RAP?
a. Large IVC diameter (>2.1 cm) but collapses > 50%
b. Normal IVC diameter (<2.1 cm) but collapses < 50%
When you read the article below, an impression is that b has a higher RAP.
Brennan JM, Blair JE, Goonewardena S, Ronan A, Shah D, Vasaiwala S, Kirkpatrick JN, Spencer KT. Reappraisal of the use of inferior vena cava for estimating right atrial pressure. J Am Soc Echocardiogr. 2007 Jul;20(7):857-61. PubMed PMID: 17617312.
Two historical articles worth mentioning:
(1) Moreno FL, Hagan AD, Holmen JR, Pryor TA, Strickland RD, Castle CH. Evaluation of size and dynamics of the inferior vena cava as an index of right-sided cardiac function. Am J Cardiol. 1984 Feb 1;53(4):579-85. PubMed PMID: 6695787.
(2) Kircher BJ, Himelman RB, Schiller NB. Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior vena cava. Am J Cardiol. 1990 Aug 15;66(4):493-6. PubMed PMID: 2386120.
You are right, evidence has been there for more than 30 years. Yet, there seems to be some confusion about this. Why is that? I plan to talk more about IVC. Stay tuned.
(1) IVC diameter is normal (<2.1 cm) and collapses >50% with a sniff: 3 mm Hg (0 - 5 mm Hg)
(2) IVC diameter is large (>2.1 cm) and collapses <50% with a sniff: 15 mm Hg (10-20 mm Hg)
(3) Either IVC diameter is normal (<2.1 cm) but collapses <50%, OR IVC diameter is large (>2.1 cm) but collapses >50%, 8 mm Hg (5-10 mm Hg)
Lang RM, Badano LP, Mor-Avi V, Afilalo J, Armstrong A, Ernande L, Flachskampf FA, Foster E, Goldstein SA, Kuznetsova T, Lancellotti P, Muraru D, Picard MH, Rietzschel ER, Rudski L, Spencer KT, Tsang W, Voigt JU. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015 Jan;28(1):1-39.e14. doi:10.1016/j.echo.2014.10.003. PubMed PMID: 25559473.
Questions
Which one could have higher RAP?
a. Large IVC diameter (>2.1 cm) but collapses > 50%
b. Normal IVC diameter (<2.1 cm) but collapses < 50%
When you read the article below, an impression is that b has a higher RAP.
Brennan JM, Blair JE, Goonewardena S, Ronan A, Shah D, Vasaiwala S, Kirkpatrick JN, Spencer KT. Reappraisal of the use of inferior vena cava for estimating right atrial pressure. J Am Soc Echocardiogr. 2007 Jul;20(7):857-61. PubMed PMID: 17617312.
Two historical articles worth mentioning:
(1) Moreno FL, Hagan AD, Holmen JR, Pryor TA, Strickland RD, Castle CH. Evaluation of size and dynamics of the inferior vena cava as an index of right-sided cardiac function. Am J Cardiol. 1984 Feb 1;53(4):579-85. PubMed PMID: 6695787.
(2) Kircher BJ, Himelman RB, Schiller NB. Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior vena cava. Am J Cardiol. 1990 Aug 15;66(4):493-6. PubMed PMID: 2386120.
You are right, evidence has been there for more than 30 years. Yet, there seems to be some confusion about this. Why is that? I plan to talk more about IVC. Stay tuned.
Sunday, June 9, 2019
IVC: How to measure?
One of the most common questions I receive while teaching at various POCUS courses, either in the US or in Japan, is "Where should we measure the diameter of the inferior vena cava (IVC)?"
Well, there are recommendations from the guidelines, but they are slightly different from one to another. Let us first take a look at this guideline from ASE in 2010.
Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, Solomon SD, Louie EK, Schiller NB. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr. 2010 Jul;23(7):685-713; quiz 786-8.
doi: 10.1016/j.echo.2010.05.010. PubMed PMID: 20620859.
When you read the guideline above, they say (page 692, figure 4) "The diameter (solid line) is measured perpendicular to the long axis of the IVC at end-expiration, just proximal to the junction of the hepatic veins that lie approximately 0.5 to 3.0 cm proximal to the ostium of the right atrium (RA)."
Given above, we could divide the way we measure IVC diameter into four components.
(1) timing of the measurement (2) Axis of the measurement (3) point of the measurement (4) point of the measurement 2
So I guess the article above explains these four points as below:
(1) Timing: End-expiration
(2) Axis: Perpendicular to the long axis of the IVC
(3) Point1: Just proximal to the junction of the hepatic veins
(4) Point2: 0.5 to 3.0 cm proximal to the ostium of the right atrium
Then let us take a look at the next guideline, again from ASE, but in 2015.
Lang RM, Badano LP, Mor-Avi V, Afilalo J, Armstrong A, Ernande L, Flachskampf FA, Foster E, Goldstein SA, Kuznetsova T, Lancellotti P, Muraru D, Picard MH, Rietzschel ER, Rudski L, Spencer KT, Tsang W, Voigt JU. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015 Jan;28(1):1-39.e14. doi: 10.1016/j.echo.2014.10.003. PubMed PMID: 25559473.
When you read this article, then the point of measurement is slightly different.
"the diameter of the IVC should be measured in the subcostal view with the patient in the supine position at 1.0 to 2.0 cm from the junction with the right atrium, using the long-axis view."
(4) Point4: 1.0 to 2.0 cm from the junction with the right atrium
Last, not the least, a recent article from again ASE, published this year (note Epub is in 2018).
Mitchell C, Rahko PS, Blauwet LA, Canaday B, Finstuen JA, Foster MC, Horton K, Ogunyankin KO, Palma RA, Velazquez EJ. Guidelines for Performing a Comprehensive Transthoracic Echocardiographic Examination in Adults: Recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019 Jan;32(1):1-64. doi: 10.1016/j.echo.2018.06.004. Epub 2018 Oct 1. PubMed PMID: 30282592.
"The measurement should be made 1 to 2 cm proximal to the junction of the IVC and right atrium. The IVC diameter should be measured at its maximum dimension, usually during expiration."
(1) Timing: should be measured at its maximum dimension, usually during expiration
So, with all these said, I would summarize the guidelines as follows
(1) Timing: measure when it is at its maximum dimension, usually during expiration
(2) Axis: Perpendicular to the long axis of the IVC
(3) Point: 1 to 2 cm proximal to the ostium of the right atrium
Well, there are recommendations from the guidelines, but they are slightly different from one to another. Let us first take a look at this guideline from ASE in 2010.
Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, Solomon SD, Louie EK, Schiller NB. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr. 2010 Jul;23(7):685-713; quiz 786-8.
doi: 10.1016/j.echo.2010.05.010. PubMed PMID: 20620859.
When you read the guideline above, they say (page 692, figure 4) "The diameter (solid line) is measured perpendicular to the long axis of the IVC at end-expiration, just proximal to the junction of the hepatic veins that lie approximately 0.5 to 3.0 cm proximal to the ostium of the right atrium (RA)."
Given above, we could divide the way we measure IVC diameter into four components.
(1) timing of the measurement (2) Axis of the measurement (3) point of the measurement (4) point of the measurement 2
So I guess the article above explains these four points as below:
(1) Timing: End-expiration
(2) Axis: Perpendicular to the long axis of the IVC
(3) Point1: Just proximal to the junction of the hepatic veins
(4) Point2: 0.5 to 3.0 cm proximal to the ostium of the right atrium
Then let us take a look at the next guideline, again from ASE, but in 2015.
Lang RM, Badano LP, Mor-Avi V, Afilalo J, Armstrong A, Ernande L, Flachskampf FA, Foster E, Goldstein SA, Kuznetsova T, Lancellotti P, Muraru D, Picard MH, Rietzschel ER, Rudski L, Spencer KT, Tsang W, Voigt JU. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015 Jan;28(1):1-39.e14. doi: 10.1016/j.echo.2014.10.003. PubMed PMID: 25559473.
"the diameter of the IVC should be measured in the subcostal view with the patient in the supine position at 1.0 to 2.0 cm from the junction with the right atrium, using the long-axis view."
(4) Point4: 1.0 to 2.0 cm from the junction with the right atrium
Last, not the least, a recent article from again ASE, published this year (note Epub is in 2018).
Mitchell C, Rahko PS, Blauwet LA, Canaday B, Finstuen JA, Foster MC, Horton K, Ogunyankin KO, Palma RA, Velazquez EJ. Guidelines for Performing a Comprehensive Transthoracic Echocardiographic Examination in Adults: Recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019 Jan;32(1):1-64. doi: 10.1016/j.echo.2018.06.004. Epub 2018 Oct 1. PubMed PMID: 30282592.
Now, when you read this most recent guideline from the article, the point of the measurement is the same as the guideline in 2015, but the timing is slightly different.
(1) Timing: should be measured at its maximum dimension, usually during expiration
So, with all these said, I would summarize the guidelines as follows
(1) Timing: measure when it is at its maximum dimension, usually during expiration
(2) Axis: Perpendicular to the long axis of the IVC
(3) Point: 1 to 2 cm proximal to the ostium of the right atrium
Transducer Manipulation: What is "Tilt", "Rock", or "Angle"?
There seems to be a confusion in this area. For example, when you open up a textbook of echocardiography, one term may be explained in a completely different way from another textbook of POCUS. I once had a heated discussion with my colleague about the definition of each term since I learned from one textbook, whereas I believe he got the information somewhere else and to confess, now I believe he was right, and I was wrong. So where is the "GOLD" standard? The American Institute of Ultrasound in Medicine (AIUM) published a statement in 1999 where they define each maneuver, which could be used as a "GOLD" standard.
AIUM technical bulletin. Transducer manipulation. American Institute of Ultrasound in Medicine. J Ultrasound Med. 1999 Feb;18(2):169-75. PubMed PMID: 10206813.
American Society of Echocardiography has recently published an article on how to perform a comprehensive transthoracic echocardiographic examination, in which they also specifically define these terms which are essentially the same with AIUM.
Mitchell C, Rahko PS, Blauwet LA, Canaday B, Finstuen JA, Foster MC, Horton K, Ogunyankin KO, Palma RA, Velazquez EJ. Guidelines for Performing a Comprehensive Transthoracic Echocardiographic Examination in Adults: Recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019 Jan;32(1):1-64. doi: 10.1016/j.echo.2018.06.004. Epub 2018 Oct 1. PubMed PMID: 30282592.
The video below (I have found it on YouTube) might be helpful for you to understand the difference between each maneuver.
AIUM technical bulletin. Transducer manipulation. American Institute of Ultrasound in Medicine. J Ultrasound Med. 1999 Feb;18(2):169-75. PubMed PMID: 10206813.
Mitchell C, Rahko PS, Blauwet LA, Canaday B, Finstuen JA, Foster MC, Horton K, Ogunyankin KO, Palma RA, Velazquez EJ. Guidelines for Performing a Comprehensive Transthoracic Echocardiographic Examination in Adults: Recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019 Jan;32(1):1-64. doi: 10.1016/j.echo.2018.06.004. Epub 2018 Oct 1. PubMed PMID: 30282592.
The video below (I have found it on YouTube) might be helpful for you to understand the difference between each maneuver.
Advanced Critical Care Echocardiography: Complete Examination
As you may know, the National Board of Echocardiography (NBE) has launched a new Examination of Special Competence in Critical Care Echocardiography (CCEeXAM). The very first examination was performed in January 2019, and they have already received the pass (or fail) results. Congratulations to those who have passed! Me? I did take Examination of Special Competence in Adult Echocardiography (ASCeXAM). Boy, it was really a tough exam (particularly for me being a pulmonologist to take an exam for cardiologists!) and am so glad I have passed!
Passing the examination is required, but not sufficient to be the Diplomate of the board. You have to submit 150 complete advanced critical care echocardiography (ACCE) examination. But what is exactly the "complete" examination? This YouTube video below, by my mentor Dr. Paul Mayo, and my dear colleague Dr. Yonatan Greenstein explains this very nicely. For those who are new to this concept, I suggest you review this video to get an idea of what is the "Complete" examination.
https://www.youtube.com/watch?v=OJB8ZNtVAvA
Speaking of which, CHEST has a great course of advanced critical care echocardiography in the end of May to June. Dr. Mayo is a co-chair and I have been teaching there this year (Yes, just came back) and last year.
Passing the examination is required, but not sufficient to be the Diplomate of the board. You have to submit 150 complete advanced critical care echocardiography (ACCE) examination. But what is exactly the "complete" examination? This YouTube video below, by my mentor Dr. Paul Mayo, and my dear colleague Dr. Yonatan Greenstein explains this very nicely. For those who are new to this concept, I suggest you review this video to get an idea of what is the "Complete" examination.
https://www.youtube.com/watch?v=OJB8ZNtVAvA
Speaking of which, CHEST has a great course of advanced critical care echocardiography in the end of May to June. Dr. Mayo is a co-chair and I have been teaching there this year (Yes, just came back) and last year.
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