Talk:Pulsus paradoxus

message: pulsus paradoxus is a clinical sign of cardiac tamponade.On measuring the blood pressure<systoic>during expiration and inspiration, a difference of more than 10 mm Hg is observed in conditions like cardiac tamponade.Many theories have been postulated for its mechanism but is still not clear, but probably due to impaired left ventricular filling and hence decreased stroke volume.--202.79.51.59 16:51, 27 July 2006 (UTC)
thread_title: pulsus

message: There is no doubt in my mind, that i completely understand what you mean with negative pressure, nevertheless in my opinion such a thing does not exist. Negative pressure means a pressure lower than normal air/atmospheric pressure.
Reply:
-ve pressure in lung refers to lower pressure in comparison to atmospheric pressure. -ve absolute pressure does not exist, that is correct Ignatius Eric Hadinata 13:41, 3 May 2007 (UTC)
thread_title:  Negative pressure 

message: I have the impression that the cause of PP is not the pooling of blood in the lungs per se (as this normally happens physiologically).  The problem appears to be that the heart cannot keep up with the increased demand, i.e. a person with PP has demand driven heart failure.  Indicative of this is that PP is often accompanied by a Kussmaul sign.  Guntheroth et al. seems to support this contention:
:Cardiac tamponade invariably caused tachycardia and a marked decrease in cardiac output, arterial pressure, pulse pressure, and stroke volume; venous pressure and diameter increased.
Also, I found a paper that seems to support this idea:
:Frey B. Pulsus paradoxus indicating heart failure in paroxysmal supraventricular tachycardia: easy detection by pulse oximetry. Intensive Care Med. 1999 Mar;25(3):333-4. .
Nephron  T|C 20:57, 28 April 2007 (UTC)
thread_title:  Cause of pulsus paradoxus 

message: I agree, what I was trying to say was that the pooling of blood in lung is the NORMAL mechanism. In pathological conditions, there are many mechanisms of pulsus paradoxus (I got this from lectures last week again by Prof. Harrap. I'll try to reference it properly soon. Its too late at night now).
One of them is the increased intrathoracic change in pressure more than normal such as in obstructive lung disease. Others include volume depletion where the volume of blood is reduced and I agree with you: a failing heart, althought I'm not sure about the mechanism of the last one (the former two relies on the pooling of blood in lung). I'll try to get back to you on the last point (which is the same as what you've written above), but remember that the most common mistakes in medicine is assuming that only one mechanism is valid for a certain condition. If a mechanism can explain a phenomenon (such as pulsus paradoxus), it does not necessarily mean that any other mechanism is incorrect. This seems to be your problem in understanding or accepting my explanations. I'll try to get a properly written and referenced summary soon (need to do this for exam anyway) and then publish it. When I do, I can guarantee that the information is correct. Ignatius Eric Hadinata 13:30, 3 May 2007 (UTC)
thread_title: Reply

message: According to L Lilly 'Pathophysiology of Heart Disease,' Second Ed., pg. 300, Kussmaul's Sign is NOT seen in with Pulsus Paradoxus during cardiac tamponade. Rather, it is present in a constrictive pericarditis, when PP is absent.  —Preceding unsigned comment added by Jmac98103 (talk • contribs) 17:25, 24 October 2008 (UTC)
thread_title:  Kussmaul's Sign 

message: I thought that the paradox was due to the decrease in blood flow with inspiration instead of the normal increase you would see with decreased intrathoracic pressure.  —Preceding unsigned comment added by 70.129.141.218 (talk) 03:11, 24 June 2010 (UTC)
thread_title:  The "paradox"