climbermedic Posted August 3, 2006 Posted August 3, 2006 Can anyone tell me the process or why increased PaCO2 causes pulmonary vasoconstriction? This would be in the instance of COPD causing cor pulmonale and right sided heart failure... Thanks :? In brain injuries increased PaCO2 causes vasodilation correct?
Ace844 Posted August 3, 2006 Posted August 3, 2006 Do a search for pulmonary physiology, and or there is some info in the etco2 threads. Out Here, ACE844
AZCEP Posted August 3, 2006 Posted August 3, 2006 Can anyone tell me the process or why increased PaCO2 causes pulmonary vasoconstriction? This would be in the instance of COPD causing cor pulmonale and right sided heart failure... Thanks :? In brain injuries increased PaCO2 causes vasodilation correct? I think you may be looking at the end point as a cause. The increased PCO2 tends to be a result of the vasoconstriction. The cor pulmonale/right heart failure situation can also cause an increase in the CO2. COPD tends to constrict the capillary bed through the physical force that is applied as the alveoli expand against the capillaries. Check the EtCO2 thread for further.
FL_Medic Posted August 4, 2006 Posted August 4, 2006 I think you may be looking at the end point as a cause. The increased PCO2 tends to be a result of the vasoconstriction. The cor pulmonale/right heart failure situation can also cause an increase in the CO2. COPD tends to constrict the capillary bed through the physical force that is applied as the alveoli expand against the capillaries. Check the EtCO2 thread for further. Also causing clubbed fingers since the same is happening at the periphreal capillaries.
AZCEP Posted August 4, 2006 Posted August 4, 2006 But in the periphery, the vasoconstriction is due to a compensatory mechanism. It is attempting to keep more of the oxygenated blood in the central circulation by constricting the most distal arteriolar vessels. This takes place before the blood gets to the A-V shunt so the pressure that is available for the capillary bed drops, and the waste products build up, causing the clubbing.
tniuqs Posted August 5, 2006 Posted August 5, 2006 Can anyone tell me the process or why increased PaCO2 causes pulmonary vasoconstriction? This would be in the instance of COPD causing cor pulmonale and right sided heart failure... Thanks :? Agreed with all of the above comentary, be aware that in these cases of Pulmonary HTN that the use of Nitric Oxide is becoming more common in practice for home use, so just a caution here the nasal cannula may be providing a different "flavour" than just the norm of Oxygen. A side bar interestingly is that Nitric Oxide is found in cigerette smoke as well. Not advocating this methodolgy in field practice thought.....! In brain injuries increased PaCO2 causes vasodilation correct? True enough, the Circle of Willis is affected by decreases of C02, this was "in Past" a method to decrease ICP? This practice of Hyperventilation has fallen my the wayside, as the simple Math looks like this......ICP-MAP= CPP......so to decrease the MAP in this manner one misses the rather essential part, that being perfusion to the Brain.. Can you say Veggies! The past practice of Hyperventilation is also transient and in most cases has serious "rebound" as well. Contact pm if you would like links to research data, it is extensive "I caution". The newer improved practice is using inotropes (personally witnessed) the Patients GCS goes from 8 to 15 rapidly in some cases.....Just like winding up a play toy. A previso here would be that Sub Arachnoid, and Sub Durals respond more favorably than Intercranial Hemmorhage, so get your portable CT scanner, and ICP probes loaded in the truck....before your shift...lol. cheers squint
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