Open-lung Biopsy in Patients with Acute Respiratory Distress Syndrome

Background: It has been suggested that fibrosis present during the fibroproliferative phase of acute respiratory distress syndrome (ARDS) can be treated by corticosteroids. However, neither clinical nor microbiologic criteria permit differentiation of this fibroproliferative phase from a nosocomial pneumonia. The aim of this observational case series was to evaluate the safety and utility of open-lung biopsy (OLB) performed in patients receiving ventilatory support who had persistent ARDS despite negative bacterial cultures.

Methods: During a 4-yr period, 37 OLBs were performed in 36 of 197 patients receiving ventilatory support who had ARDS. The severity of ARDS was assessed by a lung injury score of 3.1 +/- 0.4 (mean +/- SD) and a median ratio of the partial pressure of oxygen (PaO2) to the fraction of inspired oxygen (FiO2) of 118 mmHg. Histologic examination; bacterial, fungal, and acid-fast staining; and cultures of the tissue sample were performed.

Results: Fibrosis was present in only 41% of the lung specimens obtained by OLB. Only six patients received corticosteroids (17%). In 9 of the 15 patients with fibrosis, cytomegalovirus pneumonia precluded the use of corticosteroids. Histologic cytomegalovirus pneumonia was diagnosed in 18 cases. Histologic bacterial or mycobacterial pneumonia was diagnosed in five cases. No significant change in arterial blood gases was noted as linked to the biopsy procedure except an increase of the PaO2 /FI O2 ratio. One pneumothorax was diagnosed on a chest roentgenogram 12 h after OLB. Only one patient required blood transfusion during the 48-h period after OLB (for an hemothorax). Five patients had moderate air leaks from operative chest tubes for 2-10 days.     

细胞凋亡与急性呼吸窘迫综合征

细胞凋亡在急性呼吸窘迫综合征(ARDS)的发病机制中起重要作用,其中两类细胞凋亡在肺部炎症反应及肺损伤中扮演了重要角色,其一是多形核中性粒细胞的凋亡延迟,从而导致中性粒细胞介导的炎症反应增强;其二是肺泡上皮细胞的凋亡性死亡,与ARDS也密切相关。现就近年来ARDS发病机制中细胞凋亡的研究进展作一综述。     

体外膜肺氧合治疗重症急性呼吸窘迫综合征的护理

目的 总结体外膜肺氧合(ECMO)治疗重症急性呼吸窘迫综合征(ARDS)的临床护理策略.方法 对22例机械通气效果不佳的重症ARDS患者应用ECMO治疗,同时合理调配护理人员,加强病房环境管理及各项生命指标的监测等.结果 ECMO治疗24 h后,患者氧代谢情况明显改善;住院治疗25～43 d,治愈16例,死亡6例.结论 严密监测和有效的护理是ECMO治疗成功的重要保证.     

体外膜肺氧合治疗重症急性呼吸窘迫综合征的护理

目的总结体外膜肺氧合（ECMO）治疗重症急性呼吸窘迫综合征（ARDS）的临床护理策略。方法对22例机械通气效果不佳的重症ARDS患者应用ECMO治疗，同时合理调配护理人员，加强病房环境管理及各项生命指标的监测等。结果ECMO治疗24h后，患者氧代谢情况明显改善；住院治疗25～43d，治愈16例，死亡6例。结论严密监测和有效的护理是ECMt）治疗成功的重要保证。     

传染性非典型肺炎病人的出院指导

对90例传染性非典型肺炎(SARS)痊愈病人制定出院标准教育计划，进行心理、保持良好卫生习惯、养成良好的生活习惯、定时复查等出院指导，随访3个月未发生1例病人再感染及密切接触者感染。提示详尽的出院指导是促进病人康复和控制SARS蔓延的有力保证。     

急性呼吸窘迫综合征的药物治疗

急性呼吸窘迫综合征（ARDS）是破坏性极大急性肺损伤综合征。目前ARDS的病死率很高,临床缺乏有效的治疗措施。本文主要介绍ARDS的药物治疗。     

呼吸窘迫综合征患者机械通气模式的探讨

目的 探讨急性呼吸窘迫综合征(ARDS)患者有效的机械通气模式.方法 随机将16例ARDS患者分成对照组和观察组各8例,对照组采用Belevel通气模式,观察组在对照组机械通气模式基础上加用控制性肺膨胀策略,观察治疗前及治疗后12 h、24 h、48 h的氧合指数和二氧化碳分压.结果 二氧化碳分压、氧合指数在不同组别不同观察时间的变化趋势不同(均P＜0.05),观察组与对照组二氧化碳分压、氧合指数的处理主效应差异有显著性意义(均P＜0.05).结论 ARDS患者应用机械通气可改善氧合功能,Belevel机械通气模式加控制性肺膨胀策略效果优于单纯采用Belevel机械通气模式.     

Effects of Recruiting Maneuvers in Patients with Acute Respiratory Distress Syndrome Ventilated with Protective Ventilatory Strategy

Background: A lung-protective ventilatory strategy with low tidal volume (VT) has been proposed for use in acute respiratory distress syndrome (ARDS). Alveolar derecruitment may occur during the use of a lung-protective ventilatory strategy and may be prevented by recruiting maneuvers. This study examined the hypothesis that the effectiveness of a recruiting maneuver to improve oxygenation in patients with ARDS would be influenced by the elastic properties of the lung and chest wall.

Methods: Twenty-two patients with ARDS were studied during use of the ARDSNet lung-protective ventilatory strategy: VT was set at 6 ml/kg predicted body weight and positive end-expiratory pressure (PEEP) and inspiratory oxygen fraction (Fio2) were set to obtain an arterial oxygen saturation of 90-95% and/or an arterial oxygen partial pressure (Pao2) of 60- 80 mmHg (baseline). Measurements of Pao2/Fio2, static volume-pressure curve, recruited volume (vertical shift of the volume-pressure curve), and chest wall and lung elastance (EstW and EstL: esophageal pressure) were obtained on zero end-expiratory pressure, at baseline, and at 2 and 20 min after application of a recruiting maneuver (40 cm H2O of continuous positive airway pressure for 40 s). Cardiac output (transesophageal Doppler) and mean arterial pressure were measured immediately before, during, and immediately after the recruiting maneuver. Patients were classified a priori as responders and nonresponders on the basis of the occurrence or nonoccurrence of a 50% increase in Pao2/Fio2 after the recruiting maneuver.

Results: Recruiting maneuvers increased Pao2/Fio2 by 20 +/- 3% in nonresponders (n = 11) and by 175 +/- 23% (n = 11; mean +/- standard deviation) in responders. On zero end-expiratory pressure, EstL (28.4 +/- 2.2 vs. 24.2 +/- 2.9 cm H2O/l) and EstW (10.4 +/- 1.8 vs. 5.6 +/- 0.8 cm H2O/l) were higher in nonresponders than in responders (P < 0.01). Nonresponders had been ventilated for a longer period of time than responders (7 +/- 1 vs. 1 +/- 0.3 days;P < 0.001). Cardiac output and mean arterial pressure decreased by 31 +/- 2 and 19 +/- 3% in nonresponders and by 2 +/- 1 and 2 +/- 1% in responders (P < 0.01).     

Restrictive Transfusion Practice During Extracorporeal Membrane Oxygenation Therapy for Severe Acute Respiratory Distress Syndrome

Recommendations concerning the management of hemoglobin levels and hematocrit in patients on extracorporeal membrane oxygenation (ECMO) still advise maintenance of a normal hematocrit. In contrast, current transfusion guidelines for critically ill patients support restrictive transfusion practice. We report on a series of patients receiving venovenous ECMO (vvECMO) for acute respiratory distress syndrome (ARDS) treated according to the restrictive transfusion regimen recommended for critically ill patients. We retrospectively analyzed 18 patients receiving vvECMO due to severe ARDS. Hemoglobin concentrations were kept between 7 and 9 g/dL with a transfusion trigger at 7 g/dL or when physiological transfusion triggers were apparent. We assessed baseline data, hospital mortality, time on ECMO, hemoglobin levels, hematocrit, quantities of packed red blood cells received, and lactate concentrations and compared survivors and nonsurvivors. The overall mortality of all patients on vvECMO was 38.9%. Mean hemoglobin concentration over all patients and ECMO days was 8.30 ± 0.51 g/dL, and hematocrit was 0.25 ± 0.01, with no difference between survivors and nonsurvivors. Mean numbers of given PRBCs showed a trend towards higher quantities in the group of nonsurvivors, but the difference was not significant (1.97 ± 1.47 vs. 0.96 ± 0.76 units; P = 0.07). Mean lactate clearance from the first to the third day was 45.4 ± 28.3%, with no significant difference between survivors and nonsurvivors (P = 0.19). In our cohort of patients treated with ECMO due to severe ARDS, the application of a restrictive transfusion protocol did not result in an increased mortality. Safety and feasibility of the application of a restrictive transfusion protocol in patients on ECMO must further be evaluated in randomized controlled trials.     

Permissive Hypercapnia and Intravascular Oxygenator in the Treatment of Patients with ARDS

Abstract: This open clinical study was aimed at testing the hypothesis that an intravascular oxygenator (IVOX) may help to perform permissive hypoventilation in 10 patients with severe ARDS. After initial evaluation, we tried to reduce ventilator settings before and after IVOX implantation. Before IVOX, poor clinical tolerance and worsening oxygenation did not allow for a significant decrease in ventilator settings. With IVOX, peak inspiratory pressure (PIP) was reduced from 47 to 39 cm H₂O (p = 0. 005) and minute ventilation from 13 ± 3. 5 to 11 ± 3 L/min. CO₂ removal by IVOX allowed a significant decrease in Paco₂ from 66 ± 15 to 59 ± 13 mm Hg. Improvement of oxygenation with IVOX was not signify cant. Furthermore, interruption of oxygen flow through IVOX did not change oxygenation variables. Tolerance of the IVOX device was good, but insertion of the device was followed by a significant decrease in both cardiac index and pulmonary wedge pressure. In conclusion, IVOX improves tolerance of hypoventilation by limiting hypercapnia in ARDS patients. These preliminary results must be confirmed by a randomized controlled study