A Clinical Study On Optimizing The Weaning Process To Reduce The Failure Rate Of Extubation

Objective:The clinical process after SBT(spontaneous breathing test)was studied in the process of removing the support of ventilation from patients to standardize and optimize weaning process,this study aimed to minimize the failure rate of weaning and extubation in ICU(intensive care unit)patients with mechanical ventilation.Methods:This clinical research was divided into four parts:The first part included the patients who had received mechanical ventilation for more than 48h after the endotracheal intubation,passed the SBT and underwent the weaning extubation condition.The LUS(lung ultrasound score)was performed at 30min after the SBT,patients with LUS≥14 were randomly divided into two groups:Direct extubation Group had their endotracheal tubes removed within 24 hours after SBT;Delayed extubation Group delayed extubation for further clinical optimization for improving pulmonary ventilation.Meanwhile,SBT and LUS were performed daily in Delayed extubation Group at the same time,and the tracheal catheter was removed until when the LUS<14 after successful of 30-minute SBT.The extubation success rate,the duration of mechanical ventilation and antibiotic therapy between Direct extubation Group and Delayed extubation Group were compared.In the second part,71 patients were included and divided into mechanical ventilation group and non-mechanical ventilation group according to different ventilation modes.The changes of lung LUS,diaphragmatic muscle displacement(DE),diaphragmatic muscle thickness(TE)and diaphragmatic muscle thickness fraction(DTF)in the two groups were recorded by ultrasound during 7days of ICU admission.In the third part,in order to explain the pathophysiological relationship between the results of the first two parts,we enrolled patients with the same inclusion criteria as in the first part,the changes in the diaphragmatic thickness fraction(DTF)of patients with LUS≥14 and<14 at the end of SBT were observed respectively.In the fourth part,we explored the methods of optimizing the weaning process on the basis of the first three parts.Patients who had received mechanical ventilation for more than 48h,reached the weaning condition and successfully passed SBT were comprised.Patients with LUS≥14 at 30-minute SBT were randomly divided into 3 groups and received different sequential oxygen therapies within 48 hours after extubation.Traditional oxygen therapy Group:traditional oxygen therapy(nasal or mask)were applied.NIV Group:patients were given NIV directly after extubation.HFNCO Group:Sequential oxygen therapy with HFNCO were used.Comparing the oxygen therapy effect and outcome after extubation in four groups.Results:The first part of the trial:LUS is a good method to screen out the patients with high risk of extubation failure.Clinical treatment improving pulmonary ventilation did not reduce the failure rate of extubation in patients with LUS≥14,moreover,the duration of mechanical ventilation and antibiotic use in Delayed extubation Group is longer than that of Direct extubation Group.In addition,diaphragmatic dysfunction was observed in the Delayed extubation group(diaphragmatic muscle thinning,diaphragm contraction force decreased).The second part revealed that,in the mechanical ventilation group,both the end-expiratory diaphragm thickness(TEE)and the diaphragmatic thickness fraction(DTF)decreased with the prolonged mechanical ventilation time,indicating that acquired weakness of ICU(ICU-AW)is common in patients with mechanical ventilation,and can be directly observed by ultrasound.It was speculated that the weakness of diaphragm may be the main reason for the failure of extubation in patients passed SBT.The third part showed that compared with patients with LUS<14,patients with LUS≥14 had significantly increased DTF in SBT,and the change of DTF was closely related to the change of LUS.SBT significantly increased LUS in patients,increased the load of diaphragm movement,and easily caused diaphragm fatigue.The fourth part of trial:for patients with high risk of excubation failure(LUS score≥14 at the end of SBT),after excubation using NIV or HFNCO can significantly reduce the respiratory work-load of patients and alleviate respiratory muscle fatigue.The failure rate of extubation in these patients was significantly reduced,and the time of mechanical ventilation,antibiotic use and ICU stay after extubation was shortened.Conclusions:For patients with high risk of extubation failure,the clinical treatment improving pulmonary ventilation after the succeed SBT increases the mechanical ventilation time,thus increasing the incidence of mechanical ventilation complications and failing to improve the prognosis of patients with mechanical ventilation.Mechanical ventilation induced ICU-AW in critical patients at the early stage of mechanical ventilation,this phenomenon could be used to make early diagnosis or prediction by diaphragmatic ultrasound.The diaphragm became thinner and the contractility decreased with the prolongation of mechanical ventilation.Diaphragmatic dysfunction was more pronounced in the mechanically ventilated group than in the non-mechanically ventilated groupThe contractility of the diaphragm is closely related to the degree of volume in the lungs.During 30-minute SBT,diaphragmatic contraction acts differently depending on the degree of pulmonary aeration.Increased diaphragmatic contractility in patients with greater lung aeration loss indicates an additional respiratory effort that would contribute to an increase in tidal lung volume.Further studies are needed to evaluate the benefits of combined evaluation of lung aeration and diaphragmatic function in predicting successful weaning of patients from mechanical ventilation.In this case,respiratory muscles are prone to fatigue and not conducive to the production of tidal volume.It was not appropriate to assess the success rate of weaning solely on the basis of pulmonary ventilation or on the basis of diaphragmatic function aloneFor ICU patients with mechanical ventilation,patients with high risk of extubation failure could be screened out by usin g lung ultrasound during the weaning program.Sequential use of HFNCO or NIV after extubation can effectively reduce the rate of extubation failure and re-intubation rate.Improved prognosis,reduced duration of ventilator time,reduced duration of antibiotic time,and reduced the length of ICU stay.