Objective To investigate the effects of exogenous pulmonary surfactant （PS） on ventilation weaning and respiratory mechanics in infants with acute lung injury（ALI） after cardiopulmonary bypass （CPB）.Methods Twelve infants underwent cardiopulmonary bypass cardiac surgery committed with ALI and difficulty in weaning from ventilation were included in this study.Exogenous PS was used in the treatment via intra-tracheal administration.The changes of blood gas，respiratory mechanics and the conditions of ventilation weaning were observed.Results After intra-tracheal PS administration，spontaneous breath remained steady；spontaneous respiratory rate significantly decreased from，tidal volume of spontaneous breath increased significantly.Three concave sign disappeared and koilosternia was alleviated.PaCO2 value decreased significantly and peak inspiratory pressure（PIP） decreased from （36.18±10.25）cm H2O to （25.11±5.14）cm H2O （Plt;0.01）.Static lung compliance （Cstat） increased from （1.49±0.65）mL·cm H2O-1·kg-1 before treatment to （1.95±0.50） mL·cm H2O-1·kg-1 6 h after treatment （Plt;0.01）；and airway resistance （Rstat）decreased from （128.17±26.34） cm H2O·L-1·s-1 before treatment to （78.56±18.22） cm H2O·L-1·s-1 6 h after treatment （Plt;0.01）.All 12 infants weaned from ventilator successfully.Conclusion Combined with PS intra-tracheal treatment，lung protective ventilation strategy can significantly improve parameters of respiratory mechanics，increase dynamic lung compliance，decrease airway resistance，which can decrease the breathing effort of the infants and make it easy to wean from ventilator.
建立人工气道实施机械通气是治疗严重呼吸衰竭过程中挽救患者生命最常用的措施之一，然而通过人工气道的机械通气也增加了相关并发症发生的机会，如呼吸机相关性肺炎（VAP）等[1]。多数患者在应用呼吸机进行通气支持治疗中，当呼吸衰竭及其病因的病情缓解或明显改善时就可以解除人工气道和终止通气支持，但20%~30%的患者需要逐渐解除呼吸机的通气支持，谓之撤机（Weaning）[1]。尽管文献中撤机的定义略有不同，但主要指的是需要逐步减弱及停止通气支持和解除人工气道的一个时间过程。有慢性呼吸功能不全的患者撤机尤为困难，撤机困难患者的撤机时间可占总机械通气时间的40%[2]。机械通气时间延长与VAP发生率和病死率增加相关。一般来说，机械通气时间gt;3 d，VAP的发生率增加；机械通气时间gt;5 d，并发的VAP为晚发性医院获得性肺炎（HAP），其感染的病原体多为耐多药细菌，治疗难度加大，病死率高于早发性HAP。因此，对于机械通气患者来说，一旦建立人工气道实施有创通气，就应该积极创造条件，尽快撤机，去除人工气道。然而过快地降低和停止通气支持以及过早的气管拔管，可导致撤机失败和再插管。因此时机不成熟的撤机和延时撤机同样可造成机械通气时间过长，导致VAP发生率和病死率升高，以及医疗费用增加[2]。撤机的模式和方法有多种，但最佳的撤机方式仍有争议[1]。近年来无创通气（NIV）作为一种撤机方式用于临床已引起人们的兴趣和关注，但至今临床研究所得结论并未达到一致，NIV是否可以作为一种常规撤机方式用于临床尚无定论。本文通过总结近年来相关的临床研究，评价NIV用于机械通气撤机的可行性和利弊，探讨需进一步优化研究方案来解决的有关问题。
Objective To study the influencing factors for duration of mechanical ventilation in chronic obstructive pulmonary disease ( COPD) patients with type II respiratory failure. Methods Twenty-eight cases of mechanical ventilated COPD patients with type II respiratory failure were enrolled from March 2006 to March 2008 in Beijing Shunyi Hospital. They were divided into two groups based on their duration of ventilation: ≤7 d group as group I, and gt; 7 d as group II. Data of heart rate and blood pressure were recorded before the trachea intubation. Clinical data of blood routine, blood gas analysis and serum biochemistry were collected and analyzed. Previous history, smoking history and subsequent complications were also recorded. Results Heart rate in the group II were significantly higher than which in the group I[ ( 121. 50 ±17. 20) /min vs ( 103. 08 ±19. 97) /min, P lt;0. 05] . The incidences of upper gastrointestinal hemorrhage and blood pressure fall immediately after intubation were 63% and 88% respectively in the group II, which were significantly higher than the group I ( 0 and 25% ) . The levels of albumin, pre-albumin, Na+ , PaO2 were ( 29. 06 ±5. 00) g /L, ( 66. 36 ±17. 72) mg/L,( 138. 45 ±4. 74) mmol /L and ( 49. 06 ±20. 11) mm Hg respectively in the group II. While in the group I, those were ( 37. 11 ±2. 73) g /L, ( 127. 70 ±35. 84) mg/L, ( 143. 29 ±3. 42) mmol /L and ( 72. 25 ±38. 69) mm Hg respectively, which showed significant differences compared with the grouop II. The incidence of previous concomitant cerebral infarction showed significant difference between the group I and group II( 33. 33% vs 0) .Conclusion The levels of albumin, pre-albumin, heart rate before the intubation, upper gastrointestinal hemorrhage and blood pressure fall immediately after the intubation are associated with duration of mechanical ventilation and may indicate the prognosis in COPD patients with type II respiratory failure.
Objective To assess the risk factors associated with extubation failure in patients who had successfully passed a spontaneous breathing trial.Methods Patients receiving invasive mechanical ventilation for over 48 h were enrolled in the study，they were admitted into Emergency ICU of Zhongshan Hospital during May 2006 and Oct.2007.A spontaneous breathing trial was conducted by a pressure support of 7 cm H2O for 30 min.Clinical data were prospectively recorded for the patient receiving full ventilatory support before and after the spontaneous breathing trial.Regarding the extubation outcome，patients were divived into extubation success group and extubation failure group.Results A total of 58 patients with a mean（±SD） age of 69.4±12.7 years passed spontaneous breathing trial and were extubated.Extubation failure occurred in 11 patients（19%）.The univariate analysis indicated the following associations with extubation failure：elderly patients（78.1±7.9 years vs 67.4±15.1years，Plt;0.05），higher rapid shallow breathing index（RSBI） value（83±12 breaths·min-1·L-1 vs 68±19 breaths·min-1·L-1，Plt;0.05）and excessive respiratory tract secretions（54.5％ vs 21.3％，Plt;0.05）.Conclusion Among routinely measured clinical variables，elderly patients，higher RSBI value and amount of respiratory tract secretions were the valuable index for predicting extubation failure despite a successful spontaneous breathing trial.
Objective To analyze the prognostic factors in the postoperative patients with prolonged mechanical ventilation after extracorporeal circulation.Methods From Oct 2004 to Oct 2007，35 cases of postoperative patients after extracorporeal circulation required mechanical ventilation for ≥24 hours in ICU were enrolled.The patients were divided into death group and survival group.Preoperative variables including blood glucose，serum albumin，creatinine and ejection fraction（EF），intra-operative variables such as cardiopulmonary bypass（CPB） duration，aortic cross clamp（ACC） time，blood transfusion，and postoperative variables such as vital sign arrival at ICU，renal function，drainage in first 24 hours，APACHEⅡ score，ventilation duration were analyzed retrospectively.Results There were significant differences in blood glucose，serum albumin，EF，CPB，ACC，fresh frozen plasma transfusion，APACHEⅡ，creatinine，APTT and oxygenation index between the death group（12 cases，34.29%） and the survival group（23 cases，65.71%）.Stepwise logistic regression analysis indicated that EF（OR=0.7973，95%CI 0.6417-0.9906） and APACHEⅡ（OR=1.8588，95%CI 1.1071-3.1210） were predictors of prognosis.Conclusions High mortality is found in postoperative patients after extracorporeal circulation with prolonged mechanical ventilation.The main predictors of prognosis were EF and APACHEⅡ.It’s important to assess preoperative condition for cardiac surgical patients completely and provide more intensive perioperative care.
Objective To investigate whether the respiratory support weaning based on adaptive support ventilation ( ASV) could reduce the duration of mechanical ventilation in patients after fast-track coronary artery bypass grafting ( CABG) . Methods After CABG during the same fast-track general anesthesia, 46 patients were randomly assigned to an ASV group or a synchronized intermittent mandatory ventilation ( SIMV) group as control. The duration of mechanical ventilation, hemodynamic parameters, and airway pressures were recorded. Meanwhile, the variables and the number of the arterial blood gas were recorded. Results The duration of mechanical ventilation was shorter in the ASV group than that in the control group [ 196( 152-286) ] min vs. 253( 196-498) min, P lt;0. 05] . The duration of ICUstay was shorterin the ASV group than that in the control group [ ( 14. 5 ±0. 7) h vs. ( 16. 8 ±0. 4 ) h, P lt;0. 01] . Fewer arterial blood analyses were performed in the ASV group than those in the control group [ 5 ( 4-7) vs.7( 6-9) , P lt; 0. 05] . Conclusions A ventilation weaning protocol based on ASV is practicable. It may accelerate tracheal extubation, shorten the length of ICU stay, and simplify ventilation management in patients after fast-track CABG.
Objective To examine the adrenal function of critically ill patients received mechanical ventilation, and explore the relationship between the occurrence of relative adrenal insufficiency ( RAI) and weaning outcome.Methods Critically ill patients who were mechanically ventilated over 48 hours were enrolled in this study. Every patient was given one shot of corticotrophin 250 μg intravenously on the first day of admission and the first day of spontaneous-breathing-trial ( SBT) . Plasma contisol level was detected by radio-immunoassay before ( T0 ) and 30 minutes ( T30 ) after the shot. Meanwhile the following parameters were recorded including APACHEⅡ, age, and cause of disease, etc. RAI was defined as the difference between T0 and T30 ≤9 μg/dL. Receiver operating characteristic ( ROC) curve was used to evaluate the accuracy of the indicators towards the weaning outcome. Results A total of 45 patients with mechanical ventilation were recruited. The successful weaning group consisted 29 patients and the failure weaning group consisted 16 patients. The incidence of RAI in the successful weaning group ( 37.9% , 11/ 29) was significantly lower than that in the failure weaning group ( 75.0% , 12 /16) ( P=0. 017) . On the first day of admission, there was no significant difference of Δcortisol between the successful weaning group and the failure weaning group [ ( 10.3 ±5.7) μg/dL vs. ( 7.5 ±4.5) μg/dL, P=0.100) . On the first SBT day, Δcortisol of the successful weaning group was significantly higher than that in the failure weaning group [ ( 10.9 ±5.1) μg/dL vs. ( 4.9 ±2.9) μg/dL, P= 0.043] . Logistic regression analysis showed that Δcortisol was an independent risk factor of weaning. ROC curve analysis showed that on the first SBT day, the area under the curve of Δcortisol was 0.872; The sensitivity and the specificity of accurate judgmentwere 0.813 and 0.828 if Δcortisol ≤6. 95 μg/dL. Conclusions The occurrence of RAI is common in critically ill patients with mechanical ventilation. The adrenal function affects the outcome of weaning, and Δcortisol may be used as an important predictive indicator for weaning outcome.
Objective To determine whether B-type natriuretic peptide （BNP） levels combined with Spontaneous breathing trial (SBT) could improve the weaning outcome. Methods Eighty-three patients who were ready to undergo a 90-minute weaning trial （low-pressure support level） were enrolled .Weaning was considered to be successful if the patient passed the trial and sustained spontaneous breathing for more than 48 h after extubation. Plasma BNP was measured just before and at the end of the trial. All patients were divided into a weaning success group and a weaning failure group according to the outcomes of weaning. Categorical variables，expressed as percentages，were analyzed with a chi-square test or a Fisher’s exact test. Continuous variables were expressed as median （25th-75th percentile） and were compared using the Wilcoxon paired test （for related samples） or the Kolgomorov-Smirnov test （for independent samples）. A two-tailed p value of less than 0.05 was taken to indicate statistical significance. Receiver operating characteristic （ROC） curve analysis was performed to assess plasma BNP’s ability to discriminate the subjects who weaned succesfully or failed. Results Overall，13 patients （16.7%） failed the weaning process （6 patients passed the trial but failed extubation）. At the end of SBT，the BNP levels of the weaning failure group were significantly higher than the weaning success group. The BNP levels of the weaning failure group were significantly higher than the weaning success group （Plt;0.001）. The area under cure （AUC） of the ROC curve of BNP to predict the failure of weaning was 0.94±0.03 （Plt;0.001）.At a cut-off level of 123 pg/mL,BNP had a predictive efficiency in weaning outcome as Yourdon’s index of 0.837，sensitivity of 92.3%，and specificity of 91.4%. Conclusion Monitoring the change of BNP during a SBT may improve weaning outcome.