Effects Of Different Inspiration To Expiration Ratios On Lung Ventilation In Patients With Mechanical Ventilation Before And After Atomized Inhalation Therapy

Objectives:To investigate the effects of different inspiration to expiration ratios on lung ventilation before and after atomized inhalation therapy in patients with mechanical ventilation through endotracheal intubation by electrical impedance tomography（EIT）.Methods:The study was conducted 120 patients with tracheal intubation mechanical ventilation in surgical intensive care unit（SICU）of our hospital.Patients were randomly divided into four groups:Group Con_1:2,Group Con_1:1,Group Ait_1:2 and Group Ait_1:1,there were 30 patients in each group.The mechanical ventilation mode of each group was pressure controlled ventilation,and the inspiratory pressure was 12 cm H₂O,ratio of inhalation and exhalation before and after atomization was 1:1 in all patients,ratio of inhalation and exhalation was 1:2 or 1:1 respectively.Four groups of mechanical ventilation patients were treated with atomized inhalation using simple atomizer for ventilator,the atomized driving oxygen flow was 6 L/min,among them,Group Con_1:2 and Group Con_1:1 inspiration to expiration ratio（I:E）are 1:2 and 1:1,the atomized drug is 4 ml of sterilized water for injection;Group Ait_1:2 and Group Ait_1:1 I:E are 1:2 and 1:1,the atomized drug was 1 mg/2 ml of budesonide suspension+250μg/2 ml of ipratropium bromide solution.The changes of local lung ventilation before and after atomization were monitored by EIT,and three time points were monitored:before atomization for 10 min（T0）,after the start of the atomizationt for 10 min（T1）and atomization after 30 min（T2）.The end-expiratory pulmonary impedance（EELI）values obtained at each time point were recorded and EELI%（EELI rate of change）was calculated.Meanwhile,Sp O₂,HR,and MAP values were also recorded.Pmean,Ppeak and Cdyn were detected before and after atomization（T0 and T2）,arterial blood gas was detected,oxygenation index was calculated,and sputum viscosity was evaluated.Results:（1）EELI%results showed that,compared with T0 in the group,all four groups increased at T1（P<0.05）,while at T2,Group Ait_1:2 and Group Ait_1:1 increased（P<0.05）.At T1 and T2,the Group Ait_1:2 increased more than the Group Con_1:2（P<0.05）, increased more than the Group Ait_1:2（P<0.05）.（2）There was no statistically significant difference in Sp O₂,HR and MAP before and after atomization in the four groups（P>0.05）.（3）There was no statistically significant difference in Pmean,Ppeak and Cdyn before and after atomization in the four groups（P>0.05）.At T2,compared with Group Ait_1:1 and Group Ait_1:2,Pmean increased,Ppeak decreased and Cdyn increased（P<0.05）.（4）The results of oxygenation index showed that the oxygenation index increased after atomization in Group Ait_1:1 and Group Ait_1:2（P<0.05）.At T2,the oxygenation index of the Group Ait_1:2 increased more than the Group Con_1:2（P<0.05）,the oxygenation index of the Group Ait_1:1 increased more than the Group Con_1:1（P<0.05）,and the oxygenation index of the Group Ait_1:1 increased more than the Group Ait_1:2（P<0.05）.（5）There was no statistically significant difference in sputum consistency before and after atomization in Group Con_1:2 and Group Con_1:1（P>0.05）,and the sputum thinness after atomization inConclusions:EIT can be used for noninvasive,bedside,dynamic and visual monitoring of pulmonary ventilation in patients with mechanical ventilation.Traumatic brain injury patients with tracheal intubation pressure control mechanical ventilation（the inspiratory pressure was 12 cm H₂O）were treated with atomized inhalation at the driving oxygen flow rate of 6 L/min.After atomization,EELI showed an increasing trend,while the heart rate and blood pressure of patients did not change significantly.However,in the1:1 inspiration to expiration ratio mode,the improvement of lung function was better than the 1:2 inspiration to expiration ratio mode,which showed that the decrease of airway peak pressure and the improvement of pulmonary dynamic compliance improved the oxygenation of patients.