The effects of intravenous hyperoxygenated solution infusion on systemic oxygenation and intrapulmonary shunt during one-lung ventilation in pigs.

Background: Many anesthetic methods have been applied to maintain acceptable oxygenation during one-lung ventilation (OLV). However, the optimal management has not been definitely determined. The aim of this study was to investigate whether intravenous hyperoxygenated solution (HOS) infusion would improve systemic oxygenation and reduce intrapulmonary shunt during OLV.

Materials And Methods: Sixteen pigs (25-35 kg) were anesthetized, tracheally intubated, and mechanically ventilated. After placement of femoral artery and pulmonary artery catheters, a left-sided double-lumen tube (DLT) was placed via tracheotomy. The animals were allocated randomly to one of the two study groups (n = 8 each); control group (C group) and hyperoxygenated solution group (H group). Animals in H group received intravenous HOS infusion immediately after the beginning of OLV via internal right jugular vein with an infusion pump, and the rate of infusion was 15 mL.kg(-l).h(-l); and in C group, the same amount of lactate Ringer's solution (LRS) was used in place of HOS. Arterial and venous blood gases analysis were recorded in three phases: during two-lung ventilation just before beginning OLV (TLV), 30 min after beginning OLV (OLV + 30), and 60 min after beginning OLV (OLV + 60). We measured arterial oxygen saturation (SaO(2)), mixing venous oxygen saturation (S(V)O(2)), partial pressure of arterial oxygen (PaO(2)), partial pressure of mixing venous oxygen (PvO(2),) oxygen contents in systemic arterial and mixed venous blood (CaO(2), CvO(2)), and venous admixture percentage (Qs/Qt%). Heart rate (HR), mean arterial pressure (MAP), mean pulmonary artery pressure (MPAP), and cardiac output (CO) were also recorded.

Results: After 30 and 60 min OLV, there was a significant decrease in PaO(2), SaO(2), PvO(2), SvO(2), CaO(2), and CvO(2), and a significant increase of Qs/Qt% in both groups (P < 0.01). The values of PaO(2), SaO(2), PvO(2), SvO(2), and CvO(2) in H group at both OLV + 30 and OLV + 60 were significantly higher than those in C group (P < 0.05, P < 0.01). Although the values of CaO(2) in H group were higher than those in C group at OLV + 30 and OLV + 60, there were no significant differences. Comparing the values of Qs/Qt% between the two groups at OLV + 30 and OLV + 60, there were also no significant differences.

Conclusions: Intravenous HOS infusion led to minimal changes in intrapulmonary shunt, nevertheless, it could ameliorate arterial oxygenation obviously during OLV. This might be a new strategy to improve systemic oxygenation during OLV.