Pulsus paradoxus - dep

[ArchivalUser]

Fa08 p262 pulsus paradoxus is seen in obstructive sleep apnea and croup
can any one plz explain the mechanism???

[ArchivalUser]

HI Dep,

let me try,

OSA&Croup...............>stridor.....>upper respiratory tract obstruction...............>increase intrathrocic pressure------------>compression of systemic vein----->reduce VR.....>hypotension.....>reduce pulse amplitude.


this s what i think.....

anybody plz clarify furthermore........

[ArchivalUser]

good work.

[ArchivalUser]

Hi drbkc

How does upper resp tract obs inc intrathoracic pressure ?
does this same mechanism work for pulsus paradoxus in asthma?

Thanx for ur help

[ArchivalUser]

Hi Dep,

for ur Q,here it is:

http://ajrccm.atsjournals.org/cgi/conten.../157/1/331

[ArchivalUser]

The mechanisms that result in the normal inspiratory decrease in systolic blood pressure and the exaggerated decline present in airways obstruction (pulsus paradoxus) have been studied in an animal model of upper airway obstruction (18), in adult volunteers breathing through an external resistive load (4, 5, 7, 14, 15), and in adults with asthma (15). The reduction in pleural pressure results in an increase in left ventricular afterload and thus a fall in stroke volume and in arterial pressure roughly proportional to the fall in pleural pressure (1). Other mechanisms may contribute to this phenomenon, including increased venous return to the right heart with resulting shift of the ventricular septum to the left limiting left ventricular end-diastolic volume (1) and direct transmission of pleural pressure changes to the intrathoracic vasculature