Effects Of Ambroxol On Respiratory Dynamics In Perioperative

Objective:To study the effect of different doses of ambroxol on lung compliance,peak pressure,mean pressure,plateau pressure and the airway resistance of patients under general anaesthesia and with mechanical ventilation.To compare the differences in the severity of cough, ability of expectoration amout of sputum,sputum properties of 24 hours after surgery.To explore the relationship between the effect and the doses of ambroxol in perioperative,futher to provide reference for clinical application.Methods: We enrolled 80 female patients with thyroidectomy under general anaesthesia and with mechanical ventilation,aged 18 to 60 years old, ASA Ⅰ- grade, excluding the Ⅱsmoking history,previous history of cardiopulmonary disease, liver and kidney disease history, spinal deformities.Using a random number table divided into four groups, 20 cases in each group:the contral group(group A,0.9%Na Cl),small doses group(group B,30 mg ambroxol), moderate doses group(group C,90 mg ambroxol),large doses group(group D,180 mg ambroxol). 30 minutes before induction of anesthesia,the control group were infused with 0.9%Na Cl 100 ml,while the experiental group were infused with different doses of ambroxol(0.9%Na Cl diluted to 100ml).Then followed by intravenous injection of midazolam 0.05mg/kg,fentanyl 3μg/kg,propofol 1-1.5mg/kg,vecuronium 0.1mg/kg,3 minutes later underwent intubation and mechanical ventilation.We ventilated patients during surgery using a volume-assist mode.We setted tidal volumes at 8 m L/kg predicted body weight(PBW) and the fraction of inspired oxygen(FIO2) at 0.80,oxygen flow 2L/min to a target Sp O2 of 92% or greater. We adjusted the respiratory rate to maintain end-tidal partial pressure of carbon dioxide(FE’CO2) between 35 mm Hg and 45 mm Hg, with an inspiration:expiration ratio of 1:2.Recorded lung compliance(C),peak pressure(Ppeak), mean pressure(Pmean),plateau pressure(Pplant) and the airway resistance(R)after intubation at 5 min(T0),10 min(T1), 30 min(T2), 60 min(T3), 90 min(T4).The degrees of cough,easy extend of expectoration,amount of sputum,sputum properies after operation were recorded at 24 hours after surgery.To assess these of the four groups,and the results apply SPSS 13.0 for statistical analysis,P<0.05 considered to be clinically significant.Results: General information of each group such as patients age,body mass index,operative time were no significant difference(P>0.05).Group A and B:compared with T0, Ppeak,Pmean, Pplant, R were increased at T1-T4(P<0.05),C of both groups were decreased(P<0.05). Group C:compared with T0 、T1, Ppeak,Pplant,R were increased at T2-T4(P<0.05),C was decreased(P <0.05). Pmean increased was no significant difference(P>0.05).Group D:compared with T0-T2, Ppeak,Pplant were increased at T3、T4(P<0.05),C was decreased(P<0.05). Pmean,R increased was no significant difference(P>0.05).Compared with group A, Ppeak,Pmean,R was decreased in group D at T4(P <0.05),C was decreased(P<0.05).Compared with group A,group B and C each indicator at each time point was no significant difference(P>0.05). There were significant differences in the severity of cough, ability of expectoration amout of sputum,sputum properties( P<0.05) between group A and D of 24 hours after surgery.Compared with group A,group B and C showed no statistical significance(P>0.05).Conclusion:Patients under general anaesthesia with mechanical ventilation,peak pressure(Ppeak), mean pressure(Pmean),plateau pressure(Pplant) and the airway resistance(R) were increased with prolonged operative time,lung compliance(C) was decreased.In perioperative, using small or moderate doses of ambroxol have no significant effect on respiratory dynamics in patients under general anaesthesia with mechanical ventilation.Using high doses of ambroxol have some improvement for anesthesia patients on lung compliance,peak pressure, and the airway resistance.Compared with the control group,it could significantly increase lung compliance, reduce the peak airway pressure and the airway resistance,and can significantly improve postoperative symptoms of cough and expectoration,conducive to the recovery of patients after surgery and improve patient comfort after general anaesthesia surgery.