| Background: Mechanical ventilation is an important means of rescue and treatment of critical care patients.However,prolonged ventilation can lead to complications such as ventilator associated pneumonia(VAP)and ventilator associated lung injury(VILI)and ventilator associated diaphragmatic dysfunction(VIDD)[1-3].At the same time increase the economic burden of patients.But,Early extybation was associated with nosocomial pneumonia,prolonged ICU stay and high mortality[4-6].So it is important to judge whether the weaning is successful or not.According to the 2007 International Consensus,the spontaneous breathing trial was identified as the majordiagnostic test to determine whether patients canbe successfully extubated.Based on the overallduration of weaning as well as the number ofspontaneous breathing trials required to liberate apatient from the ventilator,weaning was categorised into three groups(simple,difficult andprolonged weaning)[7].Another fundamental result is that mortalitywas higher in the patients with prolonged weaning,but notin the patients with difficult weaning,as compared to thesimple weaning patients.The success or failure of the first weaning trial distinguishes the simple weaning group from the difficult andprolonged weaning groups.After failure of the first weaning trial the main goal is to hasten weaning to preventdifficult weaning from becoming prolonged weaning[8].Therefore,in the group of success weaning,Judging the group of difficult weaning and the group of prolonged weaning is also worthy of clinical thinking.About 20% ~ 30% patients with mechanical ventilation is difficult weaning or prolonged weaning[8],Tools available for determining the optimal timing of extubation are still controveraial.The commonly used clinical indicators such as respiratory rate(RR),minute ventilation(MV),and airway occlusion pressure(P0.1)are often inaccurate.The value of rapid breathing index(RSBI)is limited when used to predict successful extubation during pressure support(PS)trails.Diaphragmatic ultrasound will only provide useful information during unassisted breathing.Therefore,it is necessary to study the parameters of a direct detection of diaphragm function.Negative inspiratory force(NIF)can also be used as an indicator of respiratory muscle strength.But the NIF measurements are often affected by participants' understanding and cooperation,while MRC score mainly reflects the peripheral muscle strength,although the diaphragm and limb muscles belong to skeletal muscle cells and the same way.However,mechanical ventilation and bed rest showed great differences in their [10].Therefore,NIF and MRCscore are difficult to be used as a reliable index to judge the contractility of diaphragm.At present the common clinical assessment of diaphragmatic function index: twitch trandiaphragmatic pressure(Tw Pdi)?Negative inspiratory force(NIF)and MRCscore(the UK Medicall Research Council),However,due to the need to test the esophagus and stomach capsule tube Tw Pdi,resulting in discomfort in patients with limited clinical use.Previous studies have shown that twitch airway pressure(Tw Ptr)can be predicted very well,is in the ICU,noninvasive assessment of diaphragmatic function index.Especially in the design of the T type valve connection,Tw Ptr and Tw Pdi have good consistency,it is non-invasive evaluation of diaphragm function satisfaction index.To the best of our knowledge,no literature has reported that Tw Ptr is used as a predictor of weaning.Objective:according to the muscle strength of patients,to evaluate the predictive performance of Negative inspiratory force(NIF),MRCscore,twitch tracheal pressure(Tw Ptr)in the weaning outcome.Methods: Including the patients in the time of invasive mechanical ventilation more than 48 hours and began to Spontaneous breathing test(SBT)between December 2015 and in March 2017 in the first hospital affiliated to guangzhou medical university intensive care unit.And at the beginning of the weaning from mechanical ventilation to determine patients of NIF and to assessment in patients with limb muscle strength(MRC score).At the same time,through the neck phrenic nerve magnetic stimulation for Twitch tracheal pressure(TWPtr).Results: Sixty-two subjects were recruited into the study,and 45 cases of men,17 were women.The average age was 61.3 ±15.9 years old.1.1Through the comparison of Twitch tracheal pressure(TWPtr)among the group of simple weaning,difficult weaning,prolonged weaning and failure to weaning found that the Twitch tracheal pressure(Tw Ptr)of the group of simple weaning waslower than the group of difficult weaning,prolonged weaning and failure to weaning(-16.6±8.5 vs-10.4±6.0 vs-9.3 ± 2.5 vs-13.1± 7.6,P = 0.0098 vs0.0027 vs0.011),There was no statistical difference among the group of difficult weaning,prolonged weaning and failure to weaning(P > 0.05);1.2Through the comparison of NIF value among the group of simple weaning,difficult weaning,prolonged weaning and failure to weaning found that the NIF value of the group simple weaning was lower than the group of prolonged weaning and failure weaning,the difference was statistically significant(-32.1 ± 11.2 vs-11.2 ±10.8 vs-20.4±7.9,P = 0.014 vs.0.0069),the rest of the group had no statistical difference(P > 0.05);1.3 By comparing MRC score value found between the group of simple weaning,difficult weaning,prolonged weaning and failure to weaning: the group of simple weaning was higher than the group of prolonged group(51.1±11.4 vs.37.4± 17.7,P = 0.022),There was no statistical difference among the group of difficult weaning,prolonged weaning and failure to weaning(P > 0.05);1.4By comparing the mortality rate among the groups found: the mortality rate of the simple weaning was less than that of the prolonged weaning and the weaning failure group,the difference was statistically significant(P < 0.05).2.1.1Through the ROC curve analysis found that when the TWPtr is-8.75 cm H2 O,the weaning success has the highest degree of sensitivity and specific rate,were 75.9% and 100%,respectively;the area under the ROC curve is 0.792;2.1.2If using NIF to guide the weaning,the sensitivity and specificity are 78.2% and 71.4%,respectively.the area under the ROC curve is 0.778;2.1.3And If using MRCscore to guide the weaning,the sensitivity and specificity are 67.3%,57.1%,respectively.the area under the ROC curve is 0.560;2.1.4When TWPtr combining NIF,the weaning success sensitivity and specificity rate are96.3% and 96.3% respectively,the area under the ROC curve is 0.807;2.1.5 When Tw Ptrcombining MRC score,the weaning success sensitivity and specificity rate are 85.2% and 85.2% respectively,the area under the ROC curve is 0.785;2.1.6When NIF combining MRC score,the weaning success sensitivity and specificity rate are63% and 63% respectively,the area under the ROC curve is 0.771.By comparing the area under the ROC curve,Comparison the area under the ROC curve of the indexes found,the area under the ROC curve of the index of TWPtr combining NIF is larger than the index of MRCscore,the difference was statistically significant(P = 0.031).2.2.1.in the group of weaning success,Through the comparison of the group of simple weaning and the group of non-simple weaning found: the average age of the group of simple weaning was less than the group ofnon-simple weaning(61.27 ±11.17 vs71.50 ± 8.41,P = 0.002).the APACHEII score of the group of simple weaning was lower than the group ofnon-simple weaning(16.53±6.33 vs21.58± 7.03,P = 0.014).By comparing the duration of mechanical ventilation between the group of simple weaning and the group of non-simple weaning found that duration of mechanical ventilation in the group of simple weaning was shorter than the group of non-simple weaning(19.20 ± 16.13 vs46.57 ±41.93,P = 0.007).Through the comparison of ICU stay between the group of simple weaning and the group of nonsimple weaning found that ICU stay of the group of non-simple weaning was longer than the group of simple weaning(23.89 ± 33.57 vs55.71±55.19,P = 0.49).Through the comparison of hospital stay between the group of simple weaning and the group of non-simple weaning found that hospital stay of the group of non-simple weaning was longer than the group of simple weaning,difficult weaning and failure to weaning(44.61± 34.26 vs.82.95± 56.79,P = 0.011);2.2.2Bymultivariate Logistic analysis found age and the hospital stayare significant in the equation(P = 0.022 v P = 0.016).2.2.3 After adjusting for age and hospital stay foud,If using Tw Ptr to estimate the simple weaning and the non-simple weaning,the area under the ROC curve is 0.950;If using NIF,the area under the ROC curve is 0.891;If using MRC score,the area under the ROC curve is 0.887;When TWPtr combining NIF,the area under the ROC curve0.950;When TWPtr combining MRCscore,the area under the ROC curve is 0.950;When MRCscore combining NIF the area under the ROC curve is 0.893.By comparing the area under the ROC curve for each indicator,found the difference was no statistically significant(P > 0.05).3.the analysis of underlying diseases,medicine and other factors have discovered: COPD patients and Non-COPD patients,the use of neuromuscular blocking agent and patients without using neuromuscular blocking agent,the use of hormones and patients without using hormones,TWPtr,NIF and MRC score no statistical difference(P > 0.05).Secondly by comparing the COPD,hormones and sedatives on the diaphragm and peripheral muscle,found that Tw Ptr/MRCscore of the sedative drug group is higher than the group of non-sedative drugs group(0.431± 0.44 vs 0.44 ±0.09,P = 0.02).the effects of COPD and hormone on diaphragm and peripheral muscle is similar.Conclusion:(1)It is not recommended to use MRCscore as an indicator to evaluate the weaning,especially for patients with sequential non-invasive after extubation.(2)The value of the index of Tw Ptr combined with NIF for guide the weaning is not high,so it is necessary to combine with other indexes to evaluate the weaning(3)The index of each muscle strength can distinguish between the simple weaning and the non-simpleweaning,which may indicate that the process of weaning is related to the muscle strength.(4)In this study,the effects of COPD,sedation and hormones on the muscle strength of the patients were not affected. |
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