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[Cardiac stroke volume and oxygen transport during volume controlled self-ventilation]
1Pneumologische Klinik, Zentralkrankenhaus Gauting.
Background And Aim:
In patients with ventilatory pump disorder cardiac decompensation can occur after introduction of nasal intermittent positive pressure ventilation therapy (nasal IPPV). Therefore we carried out hemodynamic measurements in eight patients.
Patients And Methods:
Before starting non-invasive ventilation and 1 hour later we measured pulmonary artery pressures, central venous pressures, pulmonary capillary wedge pressures and cardiac output. Blood gas analysis of arterial and mixed venous blood were carried out. We calculated oxygen delivery and oxygen extraction rate.
Results:
After 1 hour of ventilation cardiac output was reduced from 5.9 l/min to 4.1 l/min, oxygen delivery was reduced from 1002 ml/min to 771 ml/min. These results were significant. Three patients were measured hourly during a prolonged period of ventilation. After 4 to 6 hours cardiac output almost reached again the level before ventilation.
Conclusion:
Similar to invasive ventilation or nCPAP-therapy non-invasive ventilation (nIPPV) causes a significant reduction of cardiac output 1 hour after starting ventilation. An adaptation of cardiac output could be reached after a couple of hours.