Airway pressure release ventilation as a primary ventilatory mode in acute respiratory distress syndrome

BACKGROUND: Airway pressure release ventilation (APRV) is a ventilatory mode, which allows unsupported spontaneous breathing at any phase of the ventilatory cycle. Airway pressure release ventilation as compared with pressure support (PS), another partial ventilatory mode, has been shown to improve gas exchange and cardiac output. We hypothesized whether the use of APRV with maintained unsupported spontaneous breathing as an initial mode of ventilatory support promotes faster recovery from respiratory failure in patients with acute respiratory distress syndrome (ARDS) than PS combined with synchronized intermittent ventilation (SIMV-group). METHODS: In a randomized trial 58 patients were randomized to receive either APRV or SIMV after a predefined stabilization period. Both groups shared common physiological targets, and uniform principles of general care were followed. RESULTS: Inspiratory pressure was significantly lower in the APRV-group (25.9 +/- 0.6 vs. 28.6 +/- 0.7 cmH2O) within the first week of the study (P = 0.007). PEEP-levels and physiological variables (PaO2/FiO2-ratio, PaCO2, pH, minute ventilation, mean arterial pressure, cardiac output) were comparable between the groups. At day 28, the number of ventilator-free days was similar (13.4 +/- 1.7 in the APRV-group and 12.2 +/- 1.5 in the SIMV-group), as was the mortality (17% and 18%, respectively). CONCLUSION: We conclude that when used as a primary ventilatory mode in patients with ARDS, APRV did not differ from SIMV with PS in clinically relevant outcome.     

Pathophysiology of prone positioning in the healthy lung and in ALI/ARDS

Prone position was initially introduced in healthy anesthetized and paralyzed subjects for surgical specific reasons. Then, it was used during acute respiratory failure to improve gas exchange. The interest on prone position during ALI/ARDS progressively increased, even if the mechanisms leading to a respiratory improvement are not yet completely understood. In normal subjects, during anesthesia and paralysis, prone position determines a more homogeneous distribution of the gravitational gradient of alveolar inflation, a ventilation distributed towards the non dependent lung regions and a reverse of the gravitational distribution of regional perfusion, even if factors other than gravity are involved. Moreover, prone position causes, both in healthy subject and in obese patients, an improvement in oxygenation and in functional residual capacity without affecting respiratory system, lung and chest wall compliance. In ALI/ARDS patients, prone position lead to a reverse of the alveolar inflation and ventilation distribution, due to the reverse of hydrostatic pressure overlying lung parenchyma, the reverse of heart weight, and the changes in chest wall shape and mechanical properties. Little data are available for the modifications in regional lung perfusion. The possible mechanisms involved in oxygenation improvement during prone position in ALI/ARDS patients are: 1) increased lung volumes; 2) redistribution of lung perfusion; 3) recruitment of dorsal spaces with more homogeneous ventilation and perfusion distribution. From a clinical point of view, prone position seems to be a very promising treatment for ALI/ARDS, even if its use is not yet a standard clinical practice. We have recently finished a randomized-controlled trial in order to investigate the clinical impact of this procedure. In the preliminary phase of the study performed in 35 Italian Intensive Care Units, we studied, from 1996 to 1998, 73 patients with a PaO2/FiO2 of 123 +/- 42 and a SAPS (Simplified Acute Physiology Score) of 38 +/- 11. After the first hour of prone positioning, the PaO2/FiO2 ratio of 76% of the patients had increased by more than 20 mmHg (responder) with a mean increase of 78 +/- 53 mmHg. The proportion of responders increased to 85% after 6 hours of prone positioning. The incidence of maneuver-related complications and severe and life-threatening complications was extremely rare. The overall mortality at ICU discharge was 51% and the ICU stay was similar in survivors and non survivors (17.8 +/- 11.6 vs 17.8 +/- 11.4 days).     

Prone positioning improves oxygenation in post-traumatic lung injury--a prospective randomized trial

BACKGROUND: In a prospective randomized trial the effect of prone positioning on the duration of mechanical ventilation was evaluated in multiple trauma patients and was compared with patients ventilated in supine position. METHOD: Multiple trauma patients of the intensive care units of two university hospitals were considered eligible if they met the criteria for acute lung injury or the acute respiratory distress syndrome. Patients in the prone group (N = 21) were kept prone for at least eight hours and a maximum of 23 hours per day. Prone positioning was continued until a PaO2:FiO2 ratio of more than 300 was present in prone as well as supine position over a period of 48 hours. Patients in the supine group (N = 19) were positioned according to standard care guidelines. RESULTS: The duration of ventilatory support did not differ significantly (30 +/- 17 days in the prone group and 33 +/- 23 days in the supine group). Worst case analysis (death and deterioration of gas exchange) displayed ventilatory support for 41 +/- 29 days in the prone group and 61 +/- 35 days in the supine group (p = 0.06). The PaO2:FiO2 ratio increased significantly more in the prone group in the first four days (p = 0.03). The prevalence of Acute Respiratory Distress Syndrome (ARDS) following acute lung injury (p = 0.03) and the prevalence of pneumonia (p = 0.048) were reduced also. One patient in the prone and three patients in the supine group died due to multi organ failure (p = 0.27). CONCLUSIONS: Intermittent prone positioning was not able to reduce the duration of mechanical ventilation in this limited number of patients. However the oxygenation improved significantly over the first four days of treatment, and the prevalence of ARDS and pneumonia were reduced.     

肝移植术后急性肺损伤的治疗策略

目的探讨肝移植术后急性肺损伤（ALI）的治疗方法和策略。方法肝移植术后合并Au患者18例,于术后早期给予预防感染、限液、减少炎症反应的措施,并积极纠正低氧血症。于出现低氧血症3h内经提高吸氧浓度不能纠正低氧者,给予肺复张结合肺保护通气策略,即给予吸气压力25cmH2O呼气未正压（及PEEP）17cmH2O通气2min,扩张已萎陷实变的肺泡,随后逐步降低PEEP至压力-容积曲线低位转折点（Pinf）以上2cmH：O处,预防肺泡闭塞,保持肺泡复张。结果18例患者经综合治疗及肺复张后氧分压、氧饱和度及吸氧分数均有明显改善,除1例肺部严重感染患者肺复张后吸氧分数仅上升40％,余17例均对肺复张反应良好,吸氧分数上升＞50％。复张后平均氧分压上升68mmHg,平均氧饱和度上升9．5％,平均吸氧分数上升104．7％,改善的氧合可维持2—24h。肺复张结合肺保护通气策略纠正低氧血症的有效率为94．4％,18例Au患者均成功脱机拔管,康复出院。患者对肺复张的耐受性佳,无明显并发症。结论肝移植术后Au需及时诊断和综合治疗,肺复张结合肺保护通气策略是治疗肝移植术后Au或ARDS的安全有效措施。     

Complications of prone ventilation in patients with multisystem trauma with fulminant acute respiratory distress syndrome

INTRODUCTION: Prone ventilation improves oxygenation in selected patients with acute respiratory distress syndrome (ARDS). However, prone positioning of critically ill patients with multiple invasive lines and tubes is potentially dangerous. Trauma patients, in particular, may require special consideration because of skeletal fixation devices or prior operative procedures. Our objective was to critically evaluate our experience with prone positioning in patients with severe postinjury ARDS. METHODS: Injured patients admitted to our Level I trauma center who developed ARDS were prospectively identified. Serial lung injury severity and pulmonary mechanical data, as well as complications of prone ventilation were recorded. RESULTS: During the 12-month period ending August of 1998, nine patients with postinjury ARDS were treated with prone ventilation because of hypoxemia refractory to other ventilatory strategies. All patients suffered blunt trauma. Their mean age was 29 +/- 4.5 years; seven patients were men. The average Injury Severity Score was 26 +/- 5; and, at the time of prone positioning, the mean Lung Injury Score was 3.5. The mean PaO2/FIO2 ratio increased from 75 +/- 7 to 147 +/- 27 with prone ventilation (p < 0.05, paired t test); and in six patients, the FIO2 could be decreased. Four major complications occurred (44%). One patient experienced a midline abdominal wound dehiscence. Severe facial or upper chest wall pressure necrosis developed in two patients, despite extensive padding and careful attention to skin care. The fourth patient sustained a cardiac arrest immediately after prone positioning. CONCLUSION: Prone ventilation in postinjury patients with ARDS may improve oxygenation but has the potential for significant complications. Careful consideration is required before prone positioning in this subset of patients.     

Combining Partial Liquid Ventilation and Prone Position in Experimental Acute Lung Injury

Background: Partial liquid ventilation (PLV) and prone position can improve arterial oxygen tension (PaO2) in acute lung injury (ALI). The authors evaluated additive effects of these techniques in a saline lung lavage model of ALI.

Methods: ALI was induced in 20 medium-sized pigs (29.2 +/- 2.5 kg body weight). Gas exchange and hemodynamic parameters were determined in both supine and prone position in all animals. Thereafter, one group was assigned to PLV with two sequential doses of 15 ml/kg of perfluorocarbon (n = 10); the second group was assigned to gaseous ventilation (n = 10). Gas-exchange and hemodynamic parameters were determined at corresponding time points in both groups in prone and supine position.

Results: In the PLV group, positioning the animals prone resulted in an increase of PaO2 prior to PLV and during PLV with both doses of perfluorocarbon when compared to ALI. PLV in supine position was only effective if 30 ml/kg of perfluorocarbon was applied. In the gaseous ventilation group, PaO2 increased reproducibly compared with ALI when the animals were turned prone. A significant additive improvement of arterial oxygenation was observed during combined therapy with 30 ml/kg of perfluorocarbon and prone position in the PLV group compared with either therapy alone.     

Combining partial liquid ventilation and prone position in experimental acute lung injury.

BACKGROUND: Partial liquid ventilation (PLV) and prone position can improve arterial oxygen tension (PaO2) in acute lung injury (ALI). The authors evaluated additive effects of these techniques in a saline lung lavage model of ALI. METHODS: ALI was induced in 20 medium-sized pigs (29.2+/-2.5 kg body weight). Gas exchange and hemodynamic parameters were determined in both supine and prone position in all animals. Thereafter, one group was assigned to PLV with two sequential doses of 15 ml/kg of perfluorocarbon (n = 10); the second group was assigned to gaseous ventilation (n = 10). Gas-exchange and hemodynamic parameters were determined at corresponding time points in both groups in prone and supine position. RESULTS: In the PLV group, positioning the animals prone resulted in an increase of PaO2 prior to PLV and during PLV with both doses of perfluorocarbon when compared to ALI. PLV in supine position was only effective if 30 ml/kg of perfluorocarbon was applied. In the gaseous ventilation group, PaO2 increased reproducibly compared with ALI when the animals were turned prone. A significant additive improvement of arterial oxygenation was observed during combined therapy with 30 ml/kg of perfluorocarbon and prone position in the PLV group compared with either therapy alone. CONCLUSIONS: The authors conclude that combining PLV with prone position exerts additive effects on pulmonary gas exchange in a saline lung lavage model of ALI in medium-sized pigs.     

Airway pressure release ventilation and prone positioning in severe acute respiratory distress syndrome

BACKGROUND: Implementation of lung protective strategy in the treatment of severe Acute Respiratory Distress Syndrome (ARDS) has been reported to be associated with improved outcome. To fulfil this approach, sedation, neuromuscular blocking agents and full mechanical ventilatory support are often used in critical failure of gas exchange. CASE REPORT: We present a patient who developed multiple organ failure, including severe ARDS, after severe skin injuries and septic shock. Ventilatory strategy consisted of lung protective approach, permissive hypercapnia and prone positioning. Airway pressure release ventilation (APRV) with the patient's superimposed spontaneous breathing was implemented and maintained, also during prone episodes. Improvement of gas exhange occurred after application of combined use of APRV and prone positioning. CONCLUSION: APRV and maintenance of patients' spontaneous ventilation is feasible during prone positioning, and this approach may have beneficial synergistic effects on gas exhange in patients with severe acute lung injury.     

Comparison of oxygen cost of breathing between pressure-support ventilation and airway pressure release ventilation

We compared the oxygen cost of breathing between pressure-support ventilation (PSV) and airway pressure release ventilation (APRV). This prospective, randomized, crossover study was conducted in a mixed ICU of a university hospital. Twenty clinically stable and spontaneously breathing patients after long-term mechanical ventilation were included. The patients were randomized to start on either PSV or APRV mode and measurements were obtained after an adaptation period of 30 minutes with a PaCO2 between 35-45 mmHg and PaO2 above 60 mmHg. Patients were then switched to the other mode and the same measurements were repeated. Indirect calorimetry was performed during each ventilatory mode for a period of 30 minutes. Oxygen consumption, energy expenditure, CO2 production, and respiratory quotient were measured. The parameters did not differ significantly between the two ventilatory modes, regardless of the patient's randomization. There were no statistically significant differences with regard to respiratory rate, minute volume, and blood gas analysis. All patients tolerated both ventilatory modes without signs of discomfort. PSV and APRV produced similar results in terms of oxygen cost of breathing and other metabolic variables.     

Prone ventilation in trauma or surgical patients with acute lung injury and adult respiratory distress syndrome: is it beneficial?

BACKGROUND: To compare the effectiveness of supine versus prone kinetic therapy in mechanically ventilated trauma and surgical patients with acute lung injury (ALI) and adult respiratory distress syndrome (ARDS). METHODS: A retrospective review of all patients with ALI/ARDS who were placed on either a supine (roto-rest) or prone (roto-prone) oscillating bed was performed. Data obtained included age, revised trauma score (RTS), base deficit, Injury Severity Score (ISS), head Abbreviated Injury Scale score (AIS), chest (AIS), PaO2/FiO2 ratio, FiO2 requirement, central venous pressure (CVP), days on the bed, ventilator days, use of pressors, complications, mortality, and pulmonary-associated mortality. Data are expressed as mean+/-SE with significance attributed to p<0.05. RESULTS: From March 1, 2004 through May 31, 2006, 4,507 trauma patients were admitted and 221 were identified in the trauma registry as having ALI or ARDS. Of these, 53 met inclusion criteria. Additionally, 8 general surgery patients met inclusion criteria. Of these 61 patients, 44 patients were positioned supine, 13 were placed prone, and 4 patients that were initially placed supine were changed to prone positioning. There was no difference between the groups in age, CVP, ISS, RTS, base deficit, head AIS score, chest AIS score, abdominal AIS score, or probability of survival. The PaO2/FiO2 ratios were not different at study entry (149 vs. 153, p=NS), and both groups showed improvement in PaO2/FiO2 ratios. However, the prone group had better PaO2/FiO2 ratios than the supine group by day 5 (243 vs. 200, p=0.066). The prone group had fewer days on the ventilator (13.6 vs. 24.2, p=0.12), and shorter hospital lengths of stay (22 days vs. 40 days, p=0.08). There were four patients who failed to improve with supine kinetic therapy that were changed to prone kinetic therapy. These patients had significant improvements in PaO2/FiO2 ratio, and significantly lower FiO2 requirements. There were 18 deaths (7 pulmonary related) in the supine group and 1 death in the prone group (p < 0.01 by chi test). CONCLUSIONS: ALI/ARDS patients who received prone kinetic therapy had greater improvement in PaO2/FiO2 ratio, lower mortality, and less pulmonary-related mortality than did supine positioned patients. The use of a prone-oscillating bed appears advantageous for trauma and surgical patients with ALI/ARDS and a prospective, randomized trial is warranted.     

Role of nitric oxide in treatment of acute lung injury after surgery with extracorporeal circulation

Postoperative acute lung injury (ALI) compromises oxygen transfer across alveolar-capillary membrane with consecutive hypoxia, one of its indicators being reduction of oxygenation index PaO2/FiO2 below 40 kPa (300 mm Hg). Management of ALI includes different procedures like mechanical lung ventilation (MLV), drugs and others. One of the new possibilities for treatment of ALI is nitric oxide (NO) inhalation. The aim of this prospective study was to examine the role of NO inhalation in treatment of ALI. 14 patients with ALI developed immediately after operation with extracorporeal circulation (ECC) were included in the study. Group A (n = 8) inhaled NO and group B (n = 6) did not inhale NO during treatment of ALI. All other therapeutic measures were the same in both groups. The groups were similar in relation to demographic data, type of surgery and duration of ECC. PaO2/FiO2 was calculated before operation (T1), immediately after surgery (T2) and after lung recovery, when the need for MLV stopped (T3). The duration of MLV was also registered. PaO2/FiO2 (kPa) in referent times was in group A 54.9 +/- 1.6, 33.8 +/- 1.2 and 46.2 +/- 0.8 and in group B 52.2 +/- 1.1, 33.5 +/- 1.5 and 47.3 +/- 0.9, respectively. There was a statistically significant decrease of PaO2/FiO2 in T2 and T3 vs T1 in both groups (p < 0.05), while the difference between the groups was not statistically significant. The duration of MLV (h) in group B (28.5 +/- 1.6) was statistically significantly shorter than in group A (63.1 +/- 8.7) (p < 0.01). According to the results of this study we conclude that NO inhalation during ALI after surgery with ECC significantly reduces the duration of MVL and improves pulmonary recovery.     

双水平正压通气对急性肺损伤患者血气及血流动力学指标的影响

目的探讨应用脉搏指数连续心排血量（PiCCO）容量监测仪技术研究双水平正压通气模式对急性肺损伤（ALI）患者血气及血流动力学的影响,探讨这种新型呼吸模式应用于ALI患者的临床疗效,对循环系统的影响程度,以提高ALI的治愈率。方法42例ALI患者,男27例,女15例;年龄15～75岁。按患者的入院先后顺序将40例患者（2例未完成研究）分为两组,每组20例。双水平正压通气组：入院的第1～20例患者,给予双水平正压通气呼吸支持,采用支持/时间（S/T）模式,吸气末压初始设为8～10cmH2O,逐渐增加至14～20cmH2O,以患者舒适为宜;呼气末压初设为3～5cmH2O,逐渐增加至8～12cmH2O,吸入氧浓度（FiO2）保持不变。对照组：入院的第21～40例患者,采用辅助/控制（A/C）通气模式,并依次按5cmH2O,10cmH2O,15cmH2O,20cmH2O增加呼气末正压（PEEP）,每种压力持续30min,通气支持过程中FiO2保持不变。观察两组患者的心排血量（CO）、体循环血管阻力（SVR）等血流动力学和血气指标改变。结果两组死亡13例,其中双水平正压通气组死亡5例,对照组死亡8例。死于多器官功能衰竭7例,感染性休克3例,循环衰竭3例。双水平正压通气组气管内插管时间（2.9±0.8dvs.4.2±0.9d,t=7.737,P=0.006）和住院时间（17.2±4.5dvs.18.5±3.6d,t=2.558,P=0.039）明显短于对照组。对照组：当PEEP在5～15cmH2O范围内,患者动脉血氧分压（PaO2）、氧合指数（PaO2/FiO2）随着PEEP的增高而逐渐增加（P〈0.05）;当PEEP增加至20cmH2O时CO降低,SVR、肺循环阻力（PVR）和气道峰值压（PIP）较5～15cmH2O范围时增加（P〈0.05）。双水平正压通气组：PaO2、PaO2/FiO2随着EPAP的增高而逐渐增加,当EPAP增加至10cmH2O时PaO2、PaO2/FiO2达最大值（P〈0.05）;与对照组比较PIP明显降低（t=7.831,P=0.000）。结论对ALI/急性呼吸窘迫综合征（ARDS）患者给予双水平正压通气治疗可减少对呼吸和血     

Prone positioning and inhaled nitric oxide: synergistic therapies for acute respiratory distress syndrome

BACKGROUND: Inhaled nitric oxide (INO) and prone positioning have both been advocated as methods to improve oxygenation in patients with acute respiratory distress syndrome (ARDS). This study was designed to evaluate the relative contributions of INO and prone positioning alone and in combination on gas exchange in trauma patients with ARDS. METHODS: Sixteen patients meeting the consensus definition of ARDS were studied. Patients received mechanical ventilation in the supine position, mechanical ventilation plus INO at 1 part per million in the supine position, mechanical ventilation in the PP, and mechanical ventilation in the prone positioning plus INO at 1 part per million. A stabilization period of 1 hour was allowed at each condition. After stabilization,hemodynamic and gas exchange variables were measured. RESULTS: INO and prone positioning both increased PaO2/FIO2 compared with ventilation in the supine position. PaO2/FIO2 increased by 14% during use of INO, and 10 of 16 patients (62%) responded to INO in the supine position. PaO2/FIO2 increased by 33%, and 14 of 16 patients (87.5%) responded to the prone position.The combination of INO and prone positioning resulted in an improvement in PaO2/FIO2 in 15 of 16 patients(94%), with a mean increase in PaO2/FIO2 of 59%. Pulmonary vascular resistance was reduced during use of INO, with a greater reduction in pulmonary vascular resistance seen with INO plus prone positioning (175 +/- 36 dynes x s/cm5 vs. 134 +/- 28 dynes x s/cm5) compared with INO in the supine position (164 +/- 48 dynes x s/cm5 vs.138 +/- 44 dynes x s/cm5). There were no significant hemodynamic effects of INO or prone positioning and no complications were seen during this relative short duration of study. CONCLUSIONS: INO and prone positioning can contribute to improved oxygenation in patients with ARDS. The two therapies in combination are synergistic and may be important adjuncts to mechanical ventilation in the ARDS patient with refractory hypoxemia.     

血管外肺水指数与氧合指数评估急性肺损伤程度准确性的比较

目的 比较血管外肺水指数(EVLWI)与氧合指数(PaO2/FiO2)评估急性肺损伤(ALI)程度的准确性.方法 创伤后(创伤时间＜48 h)ALI行机械通气患者16例,性别不限,年龄18～80岁,采用PiCCO监测仪监测EVLWI,建立PiCCO监测后每隔24 h采集动脉血样,测定PaO2,计算PaO2/FiO2;同时记录EVLWI,并进行肺损伤评分(LIS).分别在建立HCCO监测后24、48、72 h时按PaO2/FiO2将患者分为PaO2/FiO2≤300组(200 mm Hg＜PaO2/FiO2≤300 mm Hg)和PaO2/FiO2≤200组(PaO2/FiO2≤200 mm Hg),按EVLWI将患者分为EVLWI＜10组(EVLWI＜10 ml/kg)和EVLWI≥10组(EVLWI≥10 ml/kg).结果 与PaO2/FiO2≤300组比较,PaO2/FiO2≤200组建立PiCCO监测后24、48 h时LIS评分差异无统计学意义(P＞0.05),建立PiCCO监测后72 h时LIS评分升高(P＜0.01).与EVLWI＜10组比较,EVLWI≥10组各时点LIS评分均升高(P＜0.05或0.01).结论 临床中PaO2/FiO2作为评估ALI程度的指标存在局限性,而EVLWI在评估ALI程度方面可能比PaO2/FiO2更准确.

Abstract：

Objective To compare extravascular lung water index (EVLWI) and oxygenation index (PaO2/FiO2) in estimation of acute lung injury(ALI) .Methods Sixteen patients with post traumatic ALI (within 48 h) of both sexes, aged 18-80 yr, were studied. The patients were mechanically ventilated. Right internal jugular vein and femoral artery were catheterized and connected to PiCCO monitor (IntelliVue MP50, Philips, Netherlands).EVLWI was monitored with the PiCCO system. PaO2 was determined every 24 h. ALI was diagnosed based on the following criteria:(1)PaO2/FiO2≤300 mm Hg; (2)X-ray chest film-patchy shadows in the bilateral lungs and (3) CVP≤12 mm Hg.Lung injury score(LIS) was recorded. The patients were divided into PaO2/FiO2≤ 300 group and ≤200 group and EVLWI ≥ 10 group and ＜ 10 group. Results There was no significant difference in LIS between PaO2/FiO2 ≤300 group and PaO2/FiO2 ≤200 group at 24 and 48 h of PiCCO monitoring. At 72 h of PiCCO monitoring LIS was significantly increased in PaO2/FiO2 ≤200 group as compared with PaO2/FiO2 ≤300 group, LIS was significantly higher in EVLWI≥ 10 group than in EVLWI ＜ 10 group at 24, 48 and 72 h of PiCCO monitoring. Conclusion EVLWI is more accurate than PaO2 /FiO2 in estimation of severity of ALI.     

Anesthesia for lung volume reduction surgery

Background: Lung volume reduction surgery (LVRS) has become a novel palliative procedure for a subgroup of patients with advanced non-bullous emphysema. METHODS: Seventy-six patients with severe emphysema were evaluated: ten patients were considered for lung transplantation and only 24 underwent LVRS. In all patients an epidural catheter was inserted between the T5-T9 space. During one lung ventilation (OLV), ventilatory setting was adjusted to avoid air trapping and/or dynamic hyperinflation and high frequency jet ventilation was used when PaO2/ FiO2 was lower than 60 mmHg in 5 patients. Permissive hypercapnia (PaCO2=53 mmHg) was allowed to avoid hyperinflation and reach hemodynamic stability. RESULTS: During OLV PaO2/FiO2 was 148+/-80 mmHg, PaCO2 53+/-11 mmHg, mPA 27+/-2 mmHg and Qsp/Qt was 38+/-6%. Although the high risk patients, there were no complications due to hypercapnia during surgery. Twenty-three patients were extubated successfully at the end of the surgery (PaO2/FiO2 179+/-34 mmHg and PaCO2 59+/-11 mmHg) and only one patient was not extubated because of air leakage and died for postoperative respiratory failure after 20 days. Another patient died because of sepsis after 15 days. Numeric Ordinal Verbal Scale (by Keele modified) was used for postoperative pain degree at 0, 12th and 24th hours. No patients had pain>2. CONCLUSIONS: In conclusion, a careful anesthesia technique with an accurate intraop monitoring associated with thoracic epidural analgesia even in Video Assisted Thoracic Surgery is suggested in LVRS patients; 12 months postoperative data confirm the validity of the procedure (FEV1 24 AE 36%, FVC 53 AE 70%, RV 265 AE 199% and 6MWT 213 AE 330 m).     

ARDS with severe hypoxia--aeromedical transportation during prone ventilation

Severe hypoxia, despite maximal conventional respiratory support, is one of the few remaining limitations to aeromedical transportation. A case of a 35-year-old female, who was referred 36 hours following major trauma for transfer by air to a tertiary center, is presented. At the time of referral the PaO2/FiO2 ratio was 48. Usual manoeuvres to improve oxygenation had only minimal impact. The patient was turned and subsequently transported prone with resultant improvement in PaO2/FiO2 ratio to 260. There were no patient- or transport-related adverse events. The implication of prone positioning during aeromedical transportation is discussed.     

肺表面活性物质气道内灌注治疗重度吸入性损伤

目的 通过外源性肺表面活性物质(Pulmonary surfactant,PS)的临床应用,探讨其临床效果和可行性。方法2例烧伤伴重度吸人性损伤(Inhalation injury,InI)的病人,应用猪肺PS10ml每2h一次气道内注人,并予辅助机械通气治疗,观察患者氧合和相关肺力学指标,判断治疗效果。结果应用外源性PS24h后,氧合相关指标PaO和PaO2／FiO2有明显升高,(A—a)DO2和RI明显降低,PaCO2变化不大;肺力学相关指标吸气时的△V／△P呈逐步增高。结论 外源性PS气道内注入,并予辅助机械通气治疗,能改善Inl患者的氧合和肺顺应性,患者对外源性PS有良好的耐受性。     

乌司他丁对主动脉夹层术后急性肺损伤治疗效果的研究

目的:探讨乌司他丁对主动脉夹层术后急性肺损伤(ALI)的治疗作用.方法:将2009年与2010年主动脉夹层术后出现ALI的18例和21例患者分别设为常规治疗组和乌司他丁治疗组.针对ALI,常规治疗组给予常规治疗,乌司他丁治疗组在常规治疗基础上应用乌司他丁300 kU+生理盐水100 ml静脉滴注,每日1次,连用3 d....     

Continuously alternating prone and supine positioning in acute lung failure]

Acute respiratory failure is still one the main problems in surgical intensive care. Unknown pathophysiological mechanisms permit only symptomatic therapy. Today ventilatory strategies by using PEEP und IRV are established to improve gas exchange and FRC by recruiting collapsed alveoli, decreasing intrapulmonary shunting and returning V/Q matching to normal. Furthermore different studies have shown the effects of supine and lateral decubitus posture in patients with acute respiratory failure. There are only rare reports on using the prone position, which doesn't require two-lung ventilation in difference to lateral position. We have studied 16 patients with acute respiratory failure by using continuous changing between prone and supine position under mechanical ventilation. All were male, aged 41.3 years in the middle and showed an average "Injury Severity Score" of 30 (13-50). 15 were trauma patients with blunt chest trauma in 11 cases. We have used prone position on threatening or manifest ARDS. In all patients we observed an increment of PaO2 during prone position on to 48 mmHg so that FiO2 could be reduced on an average of 0.2 within the first 48 h since changing patient's position. Posture changing depends on blood gas analysis, specifically on decreasing PaO2 after previous increment. Patients remained in prone and supine position at a mean of 6.3 (4.5-20) h and posture changing was proceeded over a period of 15.4 (7-32) days. No problems recording to blood pressure or mechanical ventilation appeared during prone position. 11 of 16 patients survived (68.8%), 5 died of cardiac (2) and multi organic failure (3) in connection with sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)     

High frequency oscillatory ventilation in burn patients with the acute respiratory distress syndrome

BACKGROUND: High frequency oscillatory ventilation (HFOV) improves gas exchange while providing lung protective effects during the ventilation of patients with the acute respiratory distress syndrome (ARDS). The purpose of this study was to review our experience with HFOV in adult burn patients with oxygenation failure secondary to ARDS. METHODS: Retrospective cohort review of all burn patients treated with HFOV at a regional adult burn center. RESULTS: All values are reported as the mean +/- standard deviation (S.D.). HFOV was used on 28 occasions in 25 patients (age 44 +/- 16 years, %TBSA burns 40 +/- 15, and a 28% incidence of inhalation injury) who had severe oxygenation failure from ARDS (PaO2/FiO2 ratio 98 +/- 26, and oxygenation index (OI) (FiO2 x 100 x mean airway pressure/PaO2) 27 +/- 10) following 4.8 +/- 4.4 days of conventional mechanical ventilation (CMV). After switching from CMV to HFOV, there were significant improvements in the PaO(2)/FiO2 ratio within 1h and in the oxygenation index within 24 h. The duration of HFOV was 6.1 +/- 5.8 days. HFOV was continued during 26 surgeries for 14 patients where a mean of 18 +/- 9% TBSA burns were excised and closed. The only complications related to HFOV were three episodes of severe hypercapnia. In-hospital mortality was 32%. CONCLUSIONS: HFOV was safe, and was highly effective in correcting oxygenation failure associated with ARDS in burn patients, and can be successfully used as an intra-operative ventilation modality for burn patients.