Objective To determine the usefulness of serial measurements of the rapid shallow breathing index ( f/VT , RSBI) as a predictor for successfully weaning of patients undergoing prolonged mechanical ventilation ( gt; 72 hours) . Methods 76 mechanically ventilated patients were prospectively analyzed. 120-min spontaneous breathing trial was conducted after the patients having fullfiled the traditional weaning criteria, and RSBI were continuously monitored by the ventilator at five time points ( 5, 15, 30,60, and 120 min) . A repeated measure of general linear model in SPSS 15.0 was conducted to analyze the data. Results 62 patients completed 120-minute spontaneous breath trial and in which 20 patients failed weaning. There was no significant difference of RSBI at five time points during weaning ( P gt;0. 05) . But thevariation trends of RSBI during weaning time were significant different between the successful weaning patients and the failed weaning patients ( P lt; 0. 05) . Conclusions In patients undergoing prolonged mechanical ventilation, the variation trend of RSBI is more valuable than single RSBI in the prediction ofsuccessful weaning.
Objective To study the clinical feasibility of invasive mechanical ventilation with bilevel positive airway pressure（BiPAP） non-invasive ventilator in the stable patients needing prolonged mechanical ventilation.Methods Eleven patients with respiratory failure admitted in intensive care unit（ICU）of our department，who needed prolonged mechanical ventilation，between Jun 2004 and Nov 2007 were enrolled in the study and followed until death or Jan 2008.The arterial blood gas analysis data，length of stay(LOS)，LOS after changing to BiPAP non-invasive ventilator（Synchrony，Harmony，RESPIRONICS，VPAP III ST-A，RESMED），survival time after discharge(or fulfilled the discharge standards) were reviewed retrospectively.Results The settings of inspiratory pressure，expiratory pressure and respiratory rate of non-invasive ventilation were 21.3 (16-26) cm H2O，4 cm H2O，and 16 min-1，respectively.The LOS (or up to the discharge standard) was (91.5±50.2) days.The LOS (or up to the discharge standard) after changing to BiPAP ventilator was (23.5±12.2) days.The mean survival time after discharge (or up to the discharge standard) was (353.1±296.5) days.Four patients were still alive up to the end of the study.The arterial pH，PaCO2，PaO2，and SaO2 were not significant different before and after changing to BiPAP ventilator.Conclusion The mechanical ventilation with BiPAP non-invasive ventilator via tracheotomy tube is an alternative choice for stable patients needing prolonged mechanical ventilation.
Objective To assess the value of procalcitonin ( PCT) in serum and percentage of infected cells ( PIC) in bronchoalveolar lavage fluid ( BALF) for the diagnosis of early ventilator-associatedpneumonia ( VAP) .Methods A prospective observational study was conducted in a teaching hospital. The patients consecutively admitted to the intensive care unit from January 2011 to June 2012, who received mechanical ventilation for more than 48h and clinically suspected for VAP, were recruited in the study.Patients with infection outside the lungs and previous diagnosed infection were excluded. PCT was detected and bronchoalveolar lavage was performed in the day when VAP was diagnosed. BALF cells were stained by May-Grunwald Giemsa ( MGG) for counting 100 phagocytic cells and calculating infected cells ( ICs )percentage.Results 76 of all 421 patients were enrolled in this study, 64 of which were diagnosed, 12 were under-diagnosed. The PCT [ ( 3. 48 ±1. 46) ng/mL vs. ( 1. 53 ±0. 60) ng/mL] and PIC [ ( 3. 11 ±1. 47) % vs. ( 1. 08 ±0. 29) % ] were significant higher in the patients with VAP. The threshold of 2 ng/mL of PCT and 2% of PIC corresponded to sensitivity of 78. 12% and 78. 12% , and specificity of 75. 00% and 91. 67% , respectively. The area under the receiver operating characteristic ( ROC) curve was 0. 87 ( 95% CI 78. 9%-95. 9% ) and 0. 874 ( 95% CI 79. 2% -94. 9% ) , respectively. The area under ROC curve was 0. 979, and the sensitivity was 97. 36% , specificity was 97. 36% when the two cutoff values were both achieved. Conclusion PCT and PIC are useful markers to diagnose early VAP quickly and conveniently and allow early antibiotic treatment of patients with suspected VAP.
Traditional manual testing of ventilator performance is labor-intensive, time-consuming, and prone to errors in data recording, making it difficult to meet the current demands for testing efficiency in the development and manufacturing of ventilators. Therefore, in this study we designed an automated testing system for essential performance parameters of ventilators. The system mainly comprises a ventilator airflow analyzer, an automated switch module for simulated lungs, and a test control platform. Under the control of testing software, this system can perform automated tests of critical performance parameters of ventilators and generate a final test report. To validate the effectiveness of the designed system, tests were conducted on two different brands of ventilators under four different operating conditions, comparing tidal volume, oxygen concentration, and positive end expiratory pressure accuracy using both the automated testing system and traditional manual methods. Bland-Altman statistical analysis indicated good consistency between the accuracy of automated tests and manual tests for all respiratory parameters. In terms of testing efficiency, the automated testing system required approximately one-third of the time needed for manual testing. These results demonstrate that the designed automated testing system provides a novel approach and means for quality inspection and measurement calibration of ventilators, showing broad application prospects.
目的 了解综合重症监护病房（ICU）呼吸机相关性肺炎（VAP）感染率、危险因素、病原菌分布及其耐药情况，探讨有针对性的预防控制措施。 方法 2009年1月－12月综合ICU共收治患者447例，采用主动监测方法，由ICU医务人员和专职人员每日对综合ICU病房住院时间≥48 h且撤停机械通气后48 h内的患者进行VAP监测。 结果 447例患者中住院时间≥48 h的患者168例，96例患者使用呼吸机，使用呼吸机时间182 d，ICU住院总日数1 339 d，发生VAP 17例，呼吸机使用率13.59%，VAP感染率93.4例/1 000机械通气日，根据平均病情严重程度（ASIS法）调整后的VAP感染率为2.38%。呼吸机使用方式与VAP发生有关联。检出病原菌18株，全部为Gˉ杆菌，其中鲍曼不动杆菌4株，对包括硫霉素、氨曲南在内的多种抗菌药物耐药。 结论 综合ICU病房VAP感染率为2.38%，呼吸机使用不当是VAP的危险因素，VAP致病菌为Gˉ杆菌，其中鲍曼不动杆菌耐药率达100%，并呈多重耐药性；抗生素使用时间过长，预防性使用不当是致病菌产生多重耐药的重要原因。
Objective To investigate the effects of mechanical ventilation( MV) via different tidal volume ( VT) in combination with positive end expiratory pressure( PEEP) on dogs with acute lung injury( ALI) . Methods Dog model of oleic acid-induced ALI was established. And after that animals were randomized into different MV groups ( included low VT group, VT =6 mL/kg; and high VT group, VT =20 mL/kg) and ventilated for 6 h with a PEEP of 10 cmH2O. Arterial blood gas wasmeasured before, during and after ALI model was established ( at 1 h,2 h, 4 h and 6 h during MV) . The albumin concentration in BALF and pathological change of the lung tissue were evaluated in order to determine the lung injury while animals were sacrificed after 6 h MV. Results ALI model was successfully established ( 2. 50 ±0. 80) hours after oleic acid injection. Arterial pH decreased much severer in the low VT group than the high VT group( P lt;0. 01) . PaO2 and SaO2 in ventilation groups decreased after modeling but increased after MV, and PaO2 and SaO2 were significantly higher in the low VT group than the high VT group after 6 h MV( P lt;0. 05) . PaCO2 fluctuated less in the high VT group, while it increased significantly in the low VT group after MV( P lt; 0. 01) . Oxygenation index( PaO2 /FiO2 ) was lowered after modeling( P lt; 0. 01) , decreased to about 190 mm Hg after 1 h MV. And PaO2 /FiO2 in low VT group was significantly higher than the high VT group after 6 h MV( P lt; 0. 05) . BALF albumin concentration and the lung injury score in the low VT group were both significantly lower than the high VT group( both P lt; 0. 05) . Conclusions Ventilation with PEEP could improve the oxygenation of ALI dogs, and low VT ventilation improves the oxygenation better than high VT. Otherwise, low VT could induce hypercapnia and ameliorate lung injury caused by high VT MV.
ObjectiveTo observe the effect of bundle interventions on ventilator-associated pneumonia (VAP) in Intensive Care Unit (ICU). MethodsBaseline survey among the patients undergoing mechanical ventilation was conducted during June 2011 to August 2011. During September 2011 to May 2012, the rate of VAP was monitored every three months after taking bundle measures, which included oral care, elevation of the head of the bed, daily assessment of readiness to extubation, optimizing process of devices disinfection and hand hygiene. ResultsThrough carrying out the bundle interventions, the VAP rate decreased from 61.2‰ to 34.9‰ after six months and 22.7‰ after nine months, and the ventilator utilization ratio decreased from 26.5% to 24.6% after six months and 22.6% after nine months. The alcohol-based hand disinfectant dosage was increased from 32.6 mL to 58.8 mL and 54.4 mL for each patient bed in ICU. ConclusionThe bundle intervention has been proved to be effective. Measures such as staff education, bedside supervision and monitoring data feedback can help implement bundle interventions.