The effects of humidified ventilation on arterial oxygenation and respiratory mechanics during one-lung ventilation : a randomized controlled study

Abstract

Introduction: We compared the effect of heated humidifier (HH) and heat and moisture exchanger (HME) on intra-pulmonary shunt, oxygenation and respiratory mechanics during one-lung ventilation (OLV).

Methods: Sixty-two patients undergoing lobectomy of the lung were randomly applied of heated humidifier (HH group) or heat and moisture exchanger (HME group) during OLV. Arterial and central venous blood gas analyses and respiratory variables were recorded 10 minutes after two-lung ventilation (TLV) in the lateral decubitus position (TLVbaseline), at 30 minutes (OLV30), 60 minutes (OLV60) during OLV.

Result: PaO2 is higher in the HH group than in the HME group. However, there was no statistically significant difference between the two groups. In addition, intra-pulmonary shunt (Qs/Qt) increased significantly in group HME compared with TLVbaseline during OLV. However, Qs/Qt in group HH did not increase compared with TLVbaseline during OLV. There was no significant difference of Qs/Qt between the two groups during OLV. During OLV, HH group demonstrated lower peak airway pressure (Ppeak), plateau airway pressure (Pplat) and mean airway pressure (Pmean) with higher dynamic compliance (Cdyn) compared with HME group. There were no significant differences in hemodynamic variables measured throughout the study period.

Conclusion: Although HH did not result in substantial improvement in oxygenation, HH affected respiratory mechanics by reducing airway pressure and by improving lung compliance during OLV in the lateral decubitus position.