To evaluate the development prevention and treatment of pneumonic injury after operation on aged patients with abdominal infection. We analyzed 77 aged patients (＞60 y) admitted from Jan. 1991 to Dec. 1992: 38 cases of which with abdominal infection (infection group), 39 cases without abdominal infection (non-infection group). All patients were given oxygen therapy and continuous SaO2 monitoring. Results: There were 28 patients with hypoxemia (SaO2＜95%) in infection group, with an occurrence rate of 73.7%. In non-infection group (12 patients), the rate of hyoxemia was 30.8%, which has significant difference between two groups (Ｐ＜0.001). All patients with hypoxemia were given oxygen therapy and 31 patients′ SaO2 was elevated. The efficient rate was 77.5%. Other 9 patients developed ARDS, the rate was 2.5% (9/40). In the infection group 8 patients developed ARDS with an occurrence rate of 21.1%. There was one patient with ARDS in the non-infection group, the rate was 2.6%. There was significant difference between two group (Ｐ＜0.05). Conclusions: The results suggest that hypoxemia is liable to occur in aged patients with abdominal infection after operation and these patients were liable to develop ARDS. Oxygen therapy and SaO2 monitoring is the important managements to these patients in prevention of pneumonic injury.
急性肺损伤（ALI）和急性呼吸窘迫综合征（ARDS）是指由心源性以外的各种肺内外致病因素所导致的急性进行性缺氧性呼吸衰竭，它们具有性质相同的病理生理改变，严重的ALI或ALI的最终严重阶段被定义为ARDS，临床表现以呼吸窘迫、顽固性低氧血症和非心源性肺水肿为特征，采用常规的治疗难以纠正其低氧血症，死亡率高达60%。目前，有关ALI/ARDS的研究取得较多进展，其中，能有效评估ALI病情和预测死亡率的临床参数和生化指标一直是研究热点。
Objective To compare the effects of high and low positive end-expiratory pressure( PEEP) levels on mortality and risk of barotrauma in patients with acute respiratory distress syndrome ( ARDS) . Methods Randomized controlled trials ( RCTs) were recruited from PubMed( 1966-2008. 9) ,EMBASE( 1980-2008. 9) , Cochrane Database ( Issue 2, 2008) , Chinese Cochrane Centre Database and CBMdisc ( 1978-2008. 9) . Related published and unpublished data and attached references were hand searched. All RCTs about ventilation with PEEP for patients with ARDS were included, then a systematic review were performed. Results Five eligible trials were enrolled in the systematic review. According to ventilation strategy, all trials were divided into subgroup A( low tidal volumes + high PEEP vs traditional tidal volumes + low PEEP) and subgroup B( low tidal volumes + high PEEP vs low tidal volumes + low PEEP) . In subgroup A, high PEEP was associated with a lower mortality[ RR 0. 59, 95%CI( 0. 43, 0. 82) ] and a lower prevalence of barotraumas [ RR 0. 24, 95% CI( 0. 09, 0. 70) ] in patients with ARDS. In subgroup B, the difference in mortality[ RR 0. 97, 95%CI( 0. 83, 1. 13) ] and barotraumas[ RR 1. 13, 95% CI( 0. 78, 1. 63) ]were not significant. Conclusions As compared with conventional ventilation, low tidal volumes and high PEEP ventilation strategy is associated with improved survival and a lower prevalence of barotraumas in patients with ARDS. It is necessary to further confirm the role of sole high PEEP in the ventilation strategy.
Objective To explore the effects of different humidification and heating strategies during non-invasive positive pressure ventilation( NIPPV) in patients with ALI/ARDS. Methods A total of 45 patients with ALI/ARDS were randomly divided into three groups to receive NIPPV with different humidification and heating strategies, ie. Group A ( humidification with a 370 Humidifier without heating) ,group B ( humidification with a 370 Humidifier along with a MR410 Heater) , and group C ( humidification and heating with aMR850 Humidifier, and a RT308 circuit heater) . The changes of air temperature, absolute humidity, relative humidity, sputum thickness and patient comfort were compared between the three groups. Sputum thickness was evaluated with AWSS scoring system. Results After humidification and heating, the air temperature, absolute humidity and AWSS score improved significantly in group B [ elevated from ( 23. 9 ±1. 0) ℃, (9.8 ±1. 3) mg/L and 2. 0 ±0. 7 respectively to ( 30. 3 ±1. 7) ℃, ( 31. 0 ±2. 3)mg/L and ( 3. 0 ±0. 9) respectively, P lt; 0. 001] and group C [ elevated from( 23. 8 ±1. 0) , ( 9. 8 ±1. 5)mg/L and ( 2. 1 ±0. 7) respectively to ( 34. 0 ±1. 1) ℃, ( 43.8 ±2. 5) mg /L and 3. 5 ±1. 0 respectively,P lt; 0. 001] . Air temperature and absolute humidity were significantly higher in group C than those in group B( P lt; 0. 001) . Of all the parameters, only absolute humidity showed a significant improvment in group A [ elevated from( 9. 9 ±1. 6) mg/L to ( 11. 9 ±0. 9) mg/L, P lt; 0. 001] . The degree of comfort in group C was significantly higher than that in group A and B [ 8. 0 ±1. 7 vs 5. 0 ±1. 2 and 3. 0 ±0. 4, respectively, P lt;0. 001] . In group A seven patients were switched to group C because of discomfort, four accepted NIPPV continuously, and two avoided invasive mechanical ventilation eventually. In group B three patients were switched to group C because of intolerance of too much condensed water in the breathing circuit, all of them accepted NIPPV continuously, and one avoided invasive mechanical ventilation eventually. Conclusions Compared with mere humidification or humidification with heating humidifier, humidification with heating humidifier and circuit heating during NIPPV can improve the absolute humidity, air temperature and patient comfort,meanwhile decreasing the sputumthickness of patients with ALI/ARDS.
Objective To explore the effects of lateral position ventilation on lung volume and oxygenation in patients with acute respiratory distress syndrome ( ARDS) . Methods Fourteen patients with ARDS were enrolled. Supine position, lateral position and supine position were successively adopted and continued for one hour respectively. End-expiratory lung volume ( EELV) was measured at the end of each epoch. Effects of different position on gas exchange, lung mechanics and hemodynamics were monitored.Results EELV was increased from ( 1109 ±321) mL to ( 1376 ±381) mL after lateral ventilation ( P lt;0. 05) , and decreased to ( 1143 ±376) mL after the second supine ventilation ( P lt;0. 05) . Compared with initial supine ventilation, there was no significant difference in EELV after the second supine ventilation( P gt;0. 05) . PaO2 /FiO2 was increased from ( 154. 3 ±35. 0) mm Hg to ( 189. 9 ±60. 1) mm Hg after lateral ventilation ( P lt;0. 05) , and increased to ( 209. 2 ±75. 4) mm Hg after the second supine ventilation ( P lt; 0. 05) . Compared with initial supine ventilation, PaO2 /FiO2 was increased greatly after the secondsupine ventilation ( P lt; 0. 01) . There was no significant difference in PaCO2 , lung mechanics and hemodynamics after changing different position. Conclusion Lateral position ventilation can increase EELV and improve oxygenation in patients with ARDS.
Objective To investigate whether the new oxygenation index [ PaO2 /( FiO2 ×Paw ) ]which including mean airway pressure ( Paw ) for assessing intrapulmonary shunting of acute respiratory distress syndrome( ARDS) could be more accurate than the conventional oxygenation ratio ( PaO2 /FiO2 ) .Methods Twelve patients with ARDS were recruited. All patients received mechanical ventilation under lung ventilation protective strategy ( VT 6 mL/kg, f 16 bpm, FiO2 60% ) , and had a Swan-Ganz catheter inserted. Then, pressure/ volume curves were determined by low-flow method and the lower inflection point pressure was surveyed. Subsequently, parameters of respiratory mechanics and haemodynamics were recorded while periphery and pulmonary artery blood gas analysis were performed when positive end expiratory pressure ( PEEP) were changed. PaO2 /FiO2 and Qsp/Qt were calculated through special formula respectively. Results The progressive PEEP could not change Cst, PaO2 /FiO2 , and PaO2 / ( FiO2 ×Paw) in patients with ARDS significantly ( P gt; 0. 05) . The progressive PEEP did not change Qsp/Qt significantly ( P gt;0. 05) . The Δz which was used to test the difference between the correlation coefficient of Qsp/Qt and PaO2 / ( FiO2 ×Paw) and the correlation coefficient of Qsp/Qt and PaO2 /FiO2 was 0. 571, and there was no difference between the two correlation coefficients ( P gt; 0. 05) . It was not Paw but Cst which impacted on Qsp/Qt and PaO2 /FiO2 . Conclusion PaO2 / ( FiO2 × Paw ) is equal to PaO2 /FiO2 in assessing intrapulmonary shunting of ARDS.
Objective To explore the role of renin-angiotensin system( RAS) in acute lung injury( ALI) /acute respiratory dysfunction syndrome( ARDS) by using amouse cecal ligation and puncture ( CLP)model.Methods The ALI/ARDS animal models were assessed bymeasuring blood gas, wet/dry lung weight ratio( W/D) , and lung tissue histology 18 hours after CLP operation. After the ALI/ARDS models was successfully established, immunohistochemistry, western blotting and radioimmunity were used to investigate the changes of several key enzymes of RAS, such as ACE, ACE2 and Ang Ⅱ. In addition, two groups of animals received a separate intraperitoneal injection of angiotensin-converting enzyme ( ACE) inhibitor captopril or recombinant mouse ACE2 ( rmACE2) after CLP, then the changes of RAS in ALI/ARDS modelswere observed. Results The extensive lung injuries can be observed in the lung tissues from CLP-treated animals 18 hours after operation. The CLP-induced ALI/ARDS led to an increase in the wet/dry weight ratio of the lung tissues, and a decrease in the PaO2 /FiO2 [ ( 194. 3 ±23. 9) mm Hg vs ( 346. 7 ±20. 5) mm Hg,P lt;0. 01] . Immunohistochemistry and western blotting tests of the lung tissues from CLP-treated animals showed a decrease in the ACE2 protein level. However, in both the CLP and sham mice there were no significant differences between the two groups. CLP markedly increased Ang Ⅱ level in lungs and plasma of mice, and RAS drugs significantly impacted the Ang Ⅱ levels of mice. Compared with the CLP group,captopril or rmACE2 led to a decrease of the Ang Ⅱ level in mice [ Lung: ( 1. 58 ±0. 16) fmol /mg,( 1. 65 ±0. 21) fmol /mg vs ( 2. 38 ±0. 41) fmol /mg; Plasma: ( 178. 04 ±17. 87) fmol /mL, ( 153. 74 ±10. 24) fmol /mL vs ( 213. 38 ± 25. 44) fmol /mL] . Conclusions RAS activation is one of the characteristics of CLP-induced ALI/ARDS in mice models. ACE and ACE2 in RAS have a different role in the regulation of AngⅡ synthesis, while ACE has a positive effect in generating AngⅡ, and ACE2 shows a negative effect.