During controlled mechanical ventilation as compared to spontaneous breathing, less gradient of pressure in the system exists helping with repetitively opening and closing of the alveoli. When lungs are ventilated e.g. using the positive pressure mode, by application of positive end expiratory pressure (PEEP) it prevents alveolar over distension during cycles by avoiding its repetitive opening and closing. The systemic venous blood return still depends on a pressure gradient between the extrathoracic veins and the RA (the right pressure gradient) to create adequate RV preload, but with lesser amount....(can this be quantified, and how?). AM I COMPLETELY WRONG by saying that: during controlled mechanical ventilation the inspiration does not significantly increase this gradient to the level as observed in case of spontaneous breathing to accelerate venous return while enhancing the preload?
Here are the links for the articles that you are looking for:
http://academicdepartments.musc.edu/medicine/divisions/pulmonary/fellowship_and_education/education/Critical%20Care%20Syllabus/critical_care_files/Mechanical%20Ventilation-Invasive/cardiovasc%20effects%20of%20ventilation%202009.pdf
http://integraronline.com.br/admin/download/20100222162752.pdf
Look up also other works of Michael Pinsky. See the attachments too.
In general positive pressure ventilation will cause increase in thoracic pressure and pulmonary artery pressure, so RV will feel that pressure. Though in healthy heart with normal RV function and patient with normal volume status, you will not see any effects on RV from positive pressure ventilation.
If RV is dysfunctional (systolic or Diastolic) with decreased EF, positive pressure ventilation will have detrimental effects on RV, so in that case earlier extubation is recommended.
Same applies to patients with Glenn and Fontan (single ventricle physiology) where pulmonary flow is paasive, need to be extubated ASAP
Thanks
Jai Udassi
In general positive pressure ventilation will cause increase in thoracic pressure and pulmonary artery pressure, so RV will feel that pressure. Though in healthy heart with normal RV function and patient with normal volume status, you will not see any effects on RV from positive pressure ventilation.
If RV is dysfunctional (systolic or Diastolic) with decreased EF, positive pressure ventilation will have detrimental effects on RV, so in that case earlier extubation is recommended.
Same applies to patients with Glenn and Fontan (single ventricle physiology) where pulmonary flow is paasive, need to be extubated ASAP
Thanks
Jai Udassi
Here is another Pinsky classic on Heart lung interactions during mechanical ventilation
http://0-www.ncbi.nlm.nih.gov.library.ccf.org/pubmed/22473256
great thank you Robert.
I have nice experimental data while measuring RV pressure and volume during spontaneous ventilation and during positive pressure mechanical ventilation. Data follows Dr. Pinsky's review articles you have sent. I am covered and have references for citation. Thank you again
Filip
Hello dear colleaue indeed i must say that during positive pressure ventilation there is any inspiration (negative pressure) for blood suctioning from SVC and IVC into RA but during spontaneous ventilation this mechnism is saved.
- Badges
- Science topic
- Similar topics
- Medicine
- Disease
- Disease Models
- Animal Models