Does extracorporeal membrane oxygenation attenuate hypoxic pulmonary vasoconstriction in a porcine model of global alveolar hypoxia?

• Background During severe respiratory failure, hypoxic pulmonary vasoconstriction (HPV) is partly suppressed, but may still play a role in increasing pulmonary vascular resistance (PVR). Experimental studies suggest that the degree of HPV during severe respiratory failure is dependent on pulmonary oxygen tension (PvO(2)). Therefore, it has been suggested that increasing PvO(2) by veno-venous extracorporeal membrane oxygenation (V-V ECMO) would adequately reduce PVR in V-V ECMO patients. Objective Whether increased PvO(2) by V-V ECMO decreases PVR in global alveolar hypoxia. Methods Nine landrace pigs were ventilated with a mixture of oxygen and nitrogen. After 15 minutes of stable ventilation and hemodynamics, the animals were cannulated for V-V ECMO. Starting with alveolar normoxia, the fraction of inspiratory oxygen (FIO2) was stepwise reduced to establish different degrees of alveolar hypoxia. PvO(2) was increased by V-V ECMO. Results V-V ECMO decreased PVR (from 5.5 [4.5-7.1] to 3.4 [2.6-3.9] mm Hg L-1 min, P = .006) (median (interquartile range),) during ventilation with FIO2 of 0.15. At lower FIO2, PVR increased; at FIO2 0.10 to 4.9 [4.2-7.0], P = .036, at FIO2 0.05 to 6.0 [4.3-8.6], P = .002, and at FIO2 0 to 5.4 [3.5 - 7.0] mm Hg L-1 min, P = .05. Conclusions The effect of increased PvO(2) by V-V ECMO on PVR depended highly on the degree of alveolar hypoxia. Our results partly explain why V-V ECMO does not always reduce right ventricular afterload at severe alveolar hypoxia.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Anestesi och intensivvård (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Anesthesiology and Intensive Care (hsv//eng)

Keyword

animal study

extracorporeal circulation

extracorporeal membrane oxygenation

hypoxia

hypoxic pulmonary vasoconstriction

respiratory distress syndrome

Publication and Content Type

ref (subject category)

art (subject category)