对意外或自主拔管患者的研究显示，接受完全机械通气患者的23％和开始撤机过程患者的69％并不需要重新插管，这表明机械通气患者的撤机存在被延迟的倾向，致使患者承受不必要的痛苦，增加了并发症的发生率和医疗费用。撤机过程所耗费的时间占机械通气整个时间的40％~50％ 。Esteban等的研究证明：延长通气时间增加病死率。在美国，机械通气的费用约2 000美元／d，延长通气者占总机械通气患者的6％，但却消耗ICU资源的37％。我国的撤机现状与之类似，日益增多的撤机困难患者占用各ICU的有限资源，成为医疗费用和床位周转的沉重负担。机械通气撤离的研究亟待加强。
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 evaluate the efficacy of lung-protective strategies of ventilation (LPSV) in acute respiratory distress syndrome (ARDS) patients after thoracic operation. Methods-Thirtyseven ARDS patients without preoperative complications who had underwent thoracic surgery successfully were divided into the conventional mechanical ventilation group (CMV group, n=20) and lungprotective strategies of ventilation group (LPSV group，n=17). Results of arterial blood gas, index of oxygenation (PaO2/FiO2), airway plateau pressure (Pplat), inspiration peak pressure (PIP), PEEP, after ventilation treatment 24 h and mechanical ventilation time， pulmonary barotrauma and so on were observed. Results The mechanical ventilation time， pulmonary barotrauma and mortality of the LPSV group were 7.3d, 5.9％ and 29.4％ respectively, which were significantly better than those in the CMV group(17.6d，15.0％ and 60.0％, Plt;0.05). peak inflation pressure (PIP)，Pplat(plat pressure) in the LPSV group were significantly lower than those in the CMV group (Plt;0.05). However, there were no significant differences including arterial oxygen saturation (SaO2),pH, partial pressure of carbon dioxide in artery (PaCO2) and PaO2/FiO2 in two groups. Conclusion LPSV is more effective for the patients in the ARDS patients after thoracic operation compared to CMV, which can markedly reduce the ventilatorinduced lung injuryand (VILI) and mortality.
Objectives About 12.9-50% patients of SARS (Severe Acute Respiratory Syndrome), require brief mechanical ventilation (MV) to save life. All the reported principles and guidelines for therapy SARS were based on experiences from clinical treatments and facts of inadequacy. Neither prospective randomized controlled trials (RCT) nor other high quality evidences were in dealing with SARS. Our objective is to seek safe and rational non-drugs interventions for patients with severe SARS by retrospectively reviewing clinical studies about MV all over the world, which include clinical guidelines, systematic reviews (SR), Meta-analysis, economic researches and adverse events. Methods To search MEDLINE and Cochrane Library with computer. According to the standards of inclucion or exclusion, the quality of the article which as assessed, and relevant data which were extracted double checked. The Meta-analysis was conducted if the studies had no heterogeneity. Results 14 papers were eligible. Due to the significant heterogeneity between these studies, further Meta-analysis could not be conducted, and the authors’ conclusions were described only. Conclusions The outcome of PPV is better than that of VPV. Patients who underwent PPV had a significantly lower mortality than that of VPV. Of course, the volutrauma should be watched. With low tidal volume and proper PEEP, or decreased FiO2, even permissive hypercapnia, the mortality and length of stay were cut down. Non-invasive mechanical ventilation (NIMV) was effective in treating haemodynamical stable patients, minimizing complications and reducing medical staff infection. Patients with serious dyspnea with PaO2/FiO2lt;200, no profit of NIMV, or couldn’t tolerance hypoxaemia were unlikely to benefit from this technique and needed ventilation with endotracheal intubation. Prone position could improve PaO2/FiO2, NO maybe increased pulmonary perfusion, improved V/Q, and raised oxygenation. Furthermore, Inhaled NO sequentially (SQA) was better than Inhaled NO continuouly (CTA). Some studies implied that practice of protocol-directed weaning from mechanical ventilation implemented by nurses excelled that of traditional physician-directed weaning.
摘要:目的: 评价机械通气对胸腔内脉搏氧饱和度的影响。 方法 :以食道、气管和降主动脉作为胸腔内脉搏氧饱和度的监测位点,将改制后的氧饱和度探头分别固定于上述部位,并连接于同一监护仪上。纯氧通气,待上述氧饱和度容积波波形和读数稳定,停止机械通气30s。以录像的方式记录机械通气停止前后30 s内食道、气管和降主动脉SpO2容积波和读数的变化。同时记录舌SpO2。 结果 :机械通气时,食道、气管和降主动脉三个监测位点均可获得异常高大的SpO2容积波;停止通气时,异常高大的氧饱和度波形消失。食道、气管和降主动脉脉搏容积波变异率分别为112%,74%,302%。降主动脉脉搏容积波的变异率明显高于食道和气管( 〖WTBX〗P ＜005)。机械通气停止前后30s内食道、气管和降主动脉的SpO2读数变化无显著差异(〖WTBX〗P ＞005)。 结论 :机械通气对胸腔内食道、气管和降主动脉氧饱和度读数无影响,主要影响是脉搏容积波。且各位点间脉搏氧容积波受呼吸的影响不同。Abstract: Objective: To investigate the impact of mechanical ventilation on pulse oximetry in thoracic cavity. Methods : After dogs anesthesia induction and thoracotomy, pulse oximeters were simultaneously placed at esophagus, trachea, and descending aorta, and connected with the same monitor for SpO2 monitoring. During ventilation with 100% oxygen, the mechanical ventilator was temporarily switched off for 30 seconds after high quality PPG waveforms and SpO2 readings were obtained. SpO2 signals and readings from esophagus (SeO2), trachea (StraO2), descending aorta (SDAO2) shown on the monitoring screen were recorded by the SONY video before and after stopventilation. And StonO2 were also recorded. Results : Abnormally largeamplitude PPG waves were found in normal waves at monitoring sites of esophagus, trachea, and descending aorta in all animals during ventilation; however, they disappeared without ventilator. The variation rate in ventilationinduced PPG amplitude were 112%, 74%, 302% at esophagus, trachea and descending aorta respectively. The PPG amplitude variation rate from SDAO2 was higher than that from SeO2 and StraO2 (〖WTBX〗P ＜005). However, the SpO2 readings obtained from pulse oximetries in all sites were no significantly statistical difference within 30s before and after temporarily stopventilation (〖WTBX〗P ＞005). Conclusion : Abnormally amplitude PPG waveforms from oximetry probe placed at esophagus, trachea, and descending aorta were induced by ventilation. The Variation rate in ventilationinduced PPG amplitude was various at different monitoring sites. The SpO2 readings from esophagus, trachea, and descending aorta were not significantly contaminated by ventilation.
ObjectiveTo investigate the effect of recruitment maneuver (RM) following fibrobronchoscopy in invasively mechanically ventilated (IMV) patients with excessive airway secretions or foreign body aspiration. MethodsFrom September 2012 to July 2014, 200 eligible patients were randomly assigned to intervention group (n=100) and control group (n=100) . Airway clearance by fibrobronchoscopy was conducted in both the two groups, but RM was subsequently performed only in the intervention group. Outcome measurements included oxygenation index, partial pressure of carbon dioxide (PaCO2), heart rate (HR), air way resistance (Raw) and dynamic lung compliance (Cdyn) before and 2 hours after treatment, and duration of IMV and Intensive Care Unit (ICU) stay were also analyzed. ResultsAfter treatment with fibrobronchoscopy, oxygenation index [intervention vs. control: (291.14±38.49) vs. (241.39± 35.62) mm Hg (1 mm Hg=0.133 kPa)], PaCO2 [(41.65±7.73) vs. (38.87±7.97) mm Hg] and Cdyn [(48.94±11.21) vs. (39.59±10.98) mL/cm H2O (1 cm H2O=0.098 kPa) ] were significantly increased, while HR [(95.41±20.59) , vs. (106.47±19.11) beats/min] and Raw [(17.87±8.32) vs. (23.98±7.88) cm H2O/(L·s)] were significantly decreased in both groups (P ＜ 0.01) . Duration of IMV and ICU stay in the intervention group were (15.72±6.42) and (19.85±8.12) days respectively, while in the control group were (20.49±7.21) and (27.87±10.33) days. Compared with the control group, patients in the intervention group had lower Raw, duration of IMV and ICU stay, and higher Cdyn, oxygenation index, and PaCO2 (P ＜ 0.01) , but no significant difference was found in HR (P ＞ 0.05) . ConclusionIn mechanically ventilated patients with excessive airway secretion or foreign body aspiration, recruitment maneuver following fibrobronchoscopy is of great clinical importance, due to the decrease of the duration of mechanical ventilation and ICU stay by re-inflating the collapsing alveoli, improving pulmonary ventilation and gas exchange, lung compliance and diffusion capacity.
Pressure-support ventilation (PSV) is a form of important ventilation mode. Patient-ventilator synchrony of pressure support ventilation can be divided into inspiration-triggered and expiration-triggered ones. Whether the ventilator can track the patient's inspiration and expiration very well or not is an important evaluating item of the performance of the ventilator. The ventilator should response to the patient's inspiration effort on time and deliver the air flow to the patient under various conditions, such as different patient's lung types and inspiration effort, etc. Similarly, the ventilator should be able to response to the patient's expiration action, and to decrease the patient lung's internal pressure rapidly. Using the Active Servo Lung (ASL5000) respiratory simulation system, we evaluated the spontaneous breathing of PSV mode on E5, Servo i and Evital XL. The following parameters, the delay time before flow to the patient starts once the trigger variable signaling the start of inspiration, the lowest inspiratory airway pressure generated prior to the initiation of PSV, etc. were measured.
It is difficult to select the appropriate ventilation mode in clinical mechanical ventilation. This paper presents a nonlinear multi-compartment lung model to solve the difficulty. The purpose is to optimize respiratory airflow patterns and get the minimum of the work of inspiratory phrase and lung volume acceleration, minimum of the elastic potential energy and rapidity of airflow rate changes of expiratory phrase. Sigmoidal function is used to smooth the respiratory function of nonlinear equations. The equations are established to solve nonlinear boundary conditions BVP, and finally the problem was solved with gradient descent method. Experimental results showed that lung volume and the rate of airflow after optimization had good sensitivity and convergence speed. The results provide a theoretical basis for the development of multivariable controller monitoring critically ill mechanically ventilated patients.
In the clinical practice, the mechanical ventilation is a very important assisting method to improve the patients' breath. Whether or not the parameters set for the ventilator are correct would affect the pulmonary gas exchange. In this study, we try to build an advisory system based on the gas exchange model for mechanical ventilation using fuzzy logic. The gas exchange mathematic model can simulate the individual patient's pulmonary gas exchange, and can help doctors to learn the patient's exact situation. With the fuzzy logic algorithm, the system can generate ventilator settings respond to individual patient, and provide advice to the doctors. It was evaluated in 10 intensive care patient cases, with mathematic models fitted to the retrospective data and then used to simulate patient response to changes in therapy. Compared to the ventilator set only as part of routine clinical care, the present system could reduce the inspired oxygen fraction, reduce the respiratory work, and improve gas exchange with the model simulated outcome.
ObjectiveTo evaluate the effects of home mechanical ventilation (HMV) for stable chronic obstructive pulmonary disease (COPD) patients with respiratory failure in Tongzhou district of Beijing city. MethodsTwenty stable COPD patients with respiratory failure were included in the study.During the one-year follow-up period,4 patients died and 1 withdrew and 15 patients finished the follow-up.The patients was followed up by telephone each month and guided in drug administration,HMV,and rehabilitation therapy.At the beginning of the study and one year later,the patients were interviewed and accessed on the general data,nutritional status,COPD assessment test (CAT),Borg dyspnea and respiratory fatigue score,Hamilton depression scale,Hamilton anxiety scale,and arterial blood gas analysis. ResultsAt the end of one-year follow-up,nutrition index,CAT,Borg dyspnea and respiratory fatigue score,Hamilton depression scale,Hamilton anxiety scale,pH,and PaO2 did not change significantly (P>0.05),while PaCO2 decreased significantly compared with those at the beginning of the study (P<0.05).Compared with the past year,the times of hospitalization due to acute exacerbation of COPD was significantly reduced during the follow-up year (P<0.05). ConclusionHMV can ameliorate carbon dioxide retention and reduce times of hospitalization due to acute exacerbation of COPD for COPD patients with respiratory failure.