Effect of dexmedetomidine on intrapulmonary shunt in patients with sevoflurane maintained during one-lung ventilation: A case-control study

Background: The effects of dexmedetomidine on the circulatory system are complex. It is difficult to predict its effects on intrapulmonary shunts and hypoxic pulmonary vasoconstriction in patients with one-lung ventilation. This study aimed to investigate the effect of dexmedetomidine on intrapulmonary shunt in patients with sevoflurane during one-lung ventilation. Methods: Forty patients requiring thoracoscopic lobectomy were randomly divided into the dexmedetomidine group (Group D, n = 20) and the normal saline group (Group N, n = 20). The arterial partial pressure of oxygen (PaO2), pulmonary shunt fraction (Qs/Qt), mean end-tidal sevoflurane concentration, mean arterial pressure, and heart rate were compared between the 2 groups at 3 time points: (i) after 5 minutes of two-lung ventilation (T0), (ii) after 30 minutes of one-lung ventilation (OLV) (T1), and (iii) after 45 minutes of OLV (T2). The dosage of sevoflurane from the beginning of OLV to T2 was calculated. Results: There were no significant differences in age, body mass index, and FEV1/FVC between Groups D and N (P > .05). At T0, T1, and T2, the PaO2 levels of Group D and Group N were similar (P > .05), and the PaO2 levels of Group D and Group N decreased after OLV. The Qs/Qt level of Groups D and N were similar at T0 (P > .05), and the level of Groups D and N at T1 and T2 was higher than that at T0. The Qs/Qt of Group D was statistically significantly lower than that of Group N at T1 and T2 (P < .05). Conclusion: Compared with the control group, we found that dexmedetomidine can reduce the intrapulmonary shunt fraction and improve the body's status during OLV.