Effects Of Dexmedetomidine Combined With Pulmonary Static Inflation On Lung Function In Patients With Heart Valve Disease After Cardiopulmonary Bypass Surgery

Objective To observe the effect of dexmedetomidine combined with pulmonary static inflation on lung function in patients with heart valve disease after cardiopulmonary bypass surgeryMethods Forty patients with selective heart valve replacement surgery under cardiopulmonary bypass（CPB）were selected,aged 18-65 years,ASA III-IV,NYND II-III.According to the method of random number table patients were randomly divided into two groups:dexmedetomidine group（group A,n=20）and dexmedetomidine combined with pulmonary static inflation group（group B,n=20）.Both groups of patients were intravenously pumped with dexmedetomidine 1.0μg·kg^-1·h^-1 10 min before induction of anesthesia,followed by a maintenance dose of 0.5μg·kg^-1·h^-1 until the end of the operation.During CPB,Patients in group A stopped ventilating,Patients in group B stop mechanical ventilation during cardiopulmonary bypass,adjust the oxygen flow valve and APL valve of the anesthesia machine to maintain the breathing loop pressure at 10cm H₂O,so that the lungs remain statically inflation.Observe and record before induction of anesthesia（T₀）,5 minutes before CPB（T₁）,5 minutes after CPB（T₂）,60minutes after CPB（T₃）,180 minutes after CPB（T₄）,after tracheal tube removal（T₅）and after the patient leaves the intensive care unit（T₆）,Measure and calculate and record the patient’s lung function indexes at 7 time points:oxygenation index（OI）,arterial partial pressure of oxygen（PaO₂）,alveolar-arterial differences for oxygen（A-a DO₂）,shunt fraction（Qs/Qt）,respiratory index（RI）,partial pressure of carbon dioxide（Pa CO₂）;and record the patient’s heart rate（HR）,systolic blood pressure（SBP）,diastolic blood pressure（DBP）,Mean arterial pressure（MAP）at each time point.Record the patient’s tracheal intubation time（min）and stay time（h）in the postoperative care unit,record the patient’s hospital stay（d）and the incidence of PPCsResults Intragroup comparison:Compared with T₀,the OI of the two groups of patients were lower than T₀ at T₁-T₅,and the difference was statistically significant（P<0.05）,however,the OI of the two groups of patients has an upward trend in T₁-T₅,and the upward trend of group B is more obvious than that of group A.A-a DO₂,RI,Qs/Qt of the two groups of patients were higher than T₀ at T₁-T₅,and the difference was statistically significant（P<0.05）.however,A-a DO₂,RI,Qs/Qt in the two groups showed a downward trend in T₁-T_5,and the downward trend of group B is more obvious than that of group A.and PaO₂ of the two groups of patients were higher than T₀ at T₁-T₅,and the difference was statistically significant（P<0.05）Comparison between groups:At T₂-T₅,compared with group A,the PaO₂ and OI of group B were higher than those of group A,and the difference was statistically significant（P<0.05）.At T₂-T₅,Compared with group A,A-a DO₂,RI,Qs/Qt of group B were lower than group A,the difference was statistically significant（P<0.05）.The postoperative care time（min）,stay time（h）and hospitalization days（d）of patients in group B were shorter than those in group A,and the difference was statistically significant（P<0.05）.The incidence of PPCs in group B was lower than that in group A,and the difference was statistically significant（P<0.05）.There was no significant difference in Pa CO₂ between the two groups at each time point（P>0.05）,but the Pa CO₂of the two groups was within the normal range at each time point.There was no significant difference in SBP,DBP,MAP and HR between the two groups at T₀-T₆（P>0.05）.Conclusion Compared with pure use dexmedetomidine alone,dexmedetomidine combined with pulmonary static inflation can better improve the patients’s lung function after heart valve replacement surgery and can reduce the incidence of postoperative pulmonary complications,shorten the length of hospital stay.