Effects of Dexmedetomidine Hydrochloride on Perioperative Pulmonary Shunt Fraction for Patients with Esophageal Cancer
|School||Huazhong University of Science and Technology|
|Keywords||dexmedetomidine hydrochloride one lung ventilation pulmonary shuntfraction esophagectomy thoracotomy general anesthesia|
ObjectiveDexmedetomidine hydrochloride given as a potent centralα2-adrenergic receptorhas been widely used in clinical practice. Its most important function is characterizedby the strong selectivity ofα2-adrenergic receptors. It has analgesia, sedation andmitigates adverse stress response. This drug has no property of inhabiting respiratorysystem. In this study, we wanted to investigate the effects of dexmedetomidinehydrochloride on perioperative pulmonary shunt fraction in patients with esophagealcancer and to explore the relationship between the dose and clinical effect to providesome reference.MethodsSixty ASA I～II patients（three groups,20patients in each group）scheduled foresophagectomy under general anesthesia were randomly assigned into three groups tointravenously received High-dose dexmedetomidine （HDex）、 low-dose dexmedetomidine（LDex） or saline. Patients in group HDex and group LDexrespectively received intravenously a loading dose of0.6μg/kg and0.3μg/kgdexmedetomidine over10min. Both groups HDex and LDex received a maintenancedose of0.3μg/kg/hr over half an hour. Patients in placebo group received normalsaline. After general anesthesia, two lungs ventilated for15min （TLV1）, one-lungventilated for15min （OLV1）, one-lung ventilated for1h （OLV2）, restored two lungs’ventilation for15min （TLV2）.At each time point, via internal jugular vein, radialartery blood, we can do blood gas analysis and calculate intrapulmonary shunt factionQs/Qt（%）.ResultsThe differences of age、BMI(kg·m-2)、operation time、anesthesia time、preoperative parameter(Hb(g·dl-1)、PaO2（mmHg）、PaCO2（mmHg）、SO2（%） andFEV1/FVC)among three groups were not statistically significant （P>0.05）.Comparing with the blank group at the OLV1, OLV2time points, pulmonary shuntfractions of the high-dose group and the low-dose group were statistically significant（P <0.05）, but there were not statistically significant （P>0.05） between the high-dosegroup and the low-dose group at the same time points. The rest of the time pointswere not statistically significant （P>0.05）. Dexmedetomidine groups delayed thepeak time of pulmonary shunt fraction comparing with the blank group. Thedifferences among three groups’ blood sugar were not statistically significant（P>0.05）.Conclusions1、High-dose and low-dose dexmedetomidine hydrochloride groups give a greaterimpact on the pulmonary shunt fraction over time of one lung ventilation, however,during two-lung ventilation and post-operation6hours, the impact is notsignificant.2、Dexmedetomidine hydrochloride can reduce stress response. But in this clinicaltrial, the change of blood sugar is not significant. This result may be related with surgical procedure.