Background:
@EN The purpose of this study was to measure the magnitude of the hypoxic pulmonary vasoconstriction(HPV) response to hypoxia of the left lung and the effect of positive end-expiratory pressure(PEEP) in right lung on the regional HPV of left
lung.
@ES Methods:
@EN Left thoracotomy was performed in eight female mongrel dogs. Left pulmonary blood flow (QL) was measured with electromagnetic blood flow probe and cardiac output with thermodilution technique in triplicate. Systemic and pulmonary hemodynamics
were
measured via Swan-Ganz and indwelling catheters. QL was shown as percent of cardiac output(QL%). Total right and left pulmonary vascular resistance(PVRT, PVRR and PVRL) and pulmonary shunt(Qs/OT) were calculated. Through the study, the right lung
was
ventilated continuously with 100% O2, while the left lung was either ventilated with 100% O2(control: phase I) and a gas mixture containing 4%O2, 3%CO2 and 93% N2(hypoxic: phase II and III). In phase III, 10 cmH2O PEEP was applied to the right
lung.
@ES Results:
@EN Left lung hypoxia in phase II resulted in a reduction of QL% and PaO2 and a elevation of PVRL without any changes of PVRT, Qs/QT, MPAP and pulmonary perfusion pressure(PPP). With a 10 cmH2O PEEP on the right lung in phase III, OL% returned to
the
control level, but PVRI was still higher as compared to control. PaO2 and Qs/QT were further aggravated. PVRT and PVRR were elevated in phase II and compared to phase I and II.
@ES Conclusion:
@EN It is concluded that contra-lateral PEEP during unilateral HPV may aggravate systemic hypoxemia via blood flow diversion away from the PEEPed area to the hypoxic area, but not abolish hypoxic pressor response of hypoxic area. (Korean J
Anesthesiol
1996; 30: 523~533)
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