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 Related published and unpublished data and attached references were hand searched.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 investigate the role of angiotensin-II type 1 receptor ( AT1) antagonist in treatment of acute lung injury/acute respiratory distress syndrome ( ALI/ARDS) . Methods Animal model of ALI/ARDS was induced by cecal ligation and perforation ( CLP) . ALI/ARDS animals received a separate intraperitoneal injection of several concentrations( 5, 10, 15, 20, 25 mg/kg) of AT1 inhibitor losartan after CLP, then the changes of lung injury and 7-day survival were measured. Results Oxygenation index and lung wet to dry weight ratio ( W/D) showed an improving trend when losartan was administered at doses of 5 to 15 mg/kg in ALI/ARDS rats, but aggravated above the dose of 15 mg/kg. Losartan ( 15 mg/kg) treatment significantly alleviated pulmonary edema after CLP operation, and decreased serumlevels of TNF-α, IL-6, andIL-1β [ TNF-α: ( 554. 1 ±62. 7 ) pg/mL vs. ( 759. 2 ±21. 5 ) pg/mL, P lt; 0. 01; IL-6: ( 1227. 3 ±130. 0) pg/mL vs. ( 2670. 4 ±174. 1) pg/mL, P lt; 0. 01; IL-1β: ( 444. 0 ±38. 6) pg/mL vs. ( 486. 6 ±61. 7)pg/mL, P lt; 0. 05] . 7-day survival rate also increased in losartan treatment group at a dose of 15 mg/kg( 6. 7% vs. 0 ) . Conclusions The AT1 inhibitor, losartan, can significantly prevent lung injury in ALI/ARDS after CLP, and improve the 7-day survival rate.
Objective To investigate the effects of noninvasive ventilation for the treatment of acute respiratory failure secondary to severe acute respiratory syndrome ( SARS) . Methods 127 patients with complete information were collected from the database of SARS in Guangdong province, who were all consistent with the ALI/ARDS diagnostic criteria. The patients were divided into three groups depending on ventilation status, ie. a no-ventilation group, a noninvasive ventilation group, and a mechanical ventilation group. The outcome of ventilation treatmentwas followed up.Multi-factor regression analysis was conducted to analyze the relations of ventilation treatment with ARDS and mortality, and factors associated with success of noninvasive ventilation. Results As soon as the patients met the diagnostic criteria of ALI/ARDS, the patients in the noninvasive ventilation group were in more serious condition and had a higher proportion of ARDS compared with the no-ventilation group ( P lt;0. 01) . The patients in the mechanical ventilation group had a higher mortality rate ( P lt;0.01) . 6 and 7 patients in the no-ventilation group had noninvasive ventilation and invasive ventilation thereafter, respectively. 15 patients in the noninvasive group switched to invasive ventilation. Compared with the patients without ventilation ( n =45) , the patients receiving noninvasive ventilation ( n = 61) were in more serious condition and at higher risk of developing ARDS ( P lt;0. 01) , but the mortality was not different between them ( P gt; 0. 05) . The patients who continued to receive noninvasive ventilation ( n = 40) were in more serious condition, and at higher risk of developing ARDS compared with the patients without ventilation ( n = 45) ( P lt; 0. 01) . 15 patients in the noninvasive group who switched to invasive ventilation were older than those patients continuing noninvasive ventilation.Conclusions For SARS patients fulfilling the ALI/ARDS criteria, the patients underwent noninvasive ventilation are more severe, run a higher probability of developing ARDS from ALI. But earlier initiation of noninvasive ventilation has no impact on mortality. The patients who tolerate noninvasive ventilation can avoid intubation, especially for young patients. However, the time and indication of shifting from noninvasive ventilation to invasive ventilation should be emphasized.
Objective To observe the level of vascular endothelium growth factor A( VEGF-A) in exhaled breath condensate ( EBC) of patients with acute lung injury/acute respiratory distress syndrome ( ALI/ARDS) , and investigate its clinical significance. Methods EBC of 23 patients with ALI/ARDS by mechanical ventilation in intensive care unit ( ICU) were collected with improved EcoScreen condenser. EBC of 17 normal control subjects were collected with EcoScreen condensor. The level of VEGF-A was measured by ELISA in EBC and serum. The levels of VEGF-A in EBC of patients with different grades of lung injuries were compared, and the correlation was analyzed between the level of VEGF-A and clinical indicators. Results The level of VEGF-A in EBC was lower in the patients with ALI/ARDS than that of control subjects [ ( 49. 88 ±6. 32) ng/L vs. ( 56. 50 ±6. 323) ng/L, P lt;0. 01] , the level of VEGF-A was higher in the ALI patients than that of ARDS patients [ ( 53. 56 ±5. 56) ng/L vs. ( 45. 86 ±4. 45) ng/L, P lt;0. 01] ,and higher in the survival patients than that of the died patients [ ( 51. 92 ±6. 28) ng/L vs. ( 46. 05 ± 4. 58) ng/L, P lt;0. 05] . The level of VEGF-A in EBC was negatively correlated with lung injury score and A-aDO2 /PaO2 ( r = - 0. 426 and - 0. 510, respectively, P lt;0. 05) , and positively correlated with PaO2 /FiO2 and PaO2 ( r =0. 626 and 0. 655, respectively, P lt; 0. 05) . The level of VEGF-A in serum was not different between the ALI/ARDS patients and the control subjects, between the ALI and ARDS patients, or between the survival and the died patients ( all P gt;0. 05) . The level of VEGF-A in serumhad no correlation with lung injury score, A-aDO2 /PaO2 , PaO2 /FiO2 , or PaO2 ( all P gt;0. 05) . Conclusion The changes of VEGF-A in EBC of patients with ALI/ARDSmay serve as an indicator for severity and prognosis evaluation.
Objective To review the effects of pulmonary surfactant in adult patients with acute lung injury ( ALI) /acute respiratory distress syndrome ( ARDS) . Methods Randomized controlled trials ( RCTs) were recruited from PubMed ( 1966.1-2011.3) , ISI Web of Knowledge ( all the years) and Wanfang Database ( 1982-2011) . Related published data and attached references were hand searched. All the RCTs about pulmonary surfactant for the adult patients with ALI/ARDS were included, then a meta-analysis was performed. Results Eight eligible trials were enrolled. Pooled analysis showed that treatment with pulmonary surfactant was not associated with reduction in 28 or 30-day mortality compared with the control group [ OR 1.05, 95% CI ( 0.90, 1.22 ) , P = 0.55] , neither did subgroup analysis in the pneumoia/ aspiration, sepsis, and trauma/ surgery induced ALI/ARDS patients. Three RCTs showed the oxygenation was significantly improved in adult ALI/ARDS patients receiving pulmonary surfactant compared with the control group( Plt;0.05) . Shorter mechanical ventilation days was shown in the ALI/ARDS patients receiving pulmonary surfactant in one RCT(Plt;0.05) . Conclusions Meta-analysis showed pulmonary surfactant did not reduce the 28 or 30-day mortality of adult patients with ALI/ARDS, however, improved the oxygenation. Pulmonary surfactant can be considered a therapy in ALI/ARDS.
Objective To investigate the value of continuous blood purification （CBP）in early treatment of patients with ARDSexp （ARDS caused by extrapulmonary causes），especially in reducing inflammation mediators and extravascular lung water （EVLW）.Methods According the hospital admission sequence，the patients with APACHEⅡ scores from 15 to 20 and PaO2/FiO2 from 100 to 200 were recruited.The ARDSexp patients were divide into an intervention group treated with CBP （Mode：CVVHDF，rate of displacement liquid and dialysate：1.5 L/h，rate of blood：100-200 mL/h，and the time of CBP：72 hours），and a control group without CBP treatment. The NICO and PICCO monitoring data and the survival rates were recorded and analyzed using the SPSS software. Results The mortality rate of the intervention group was lower than that of the control group （6.3% vs. 36.8%，P=0.032）. In the 72 h monitoring dada of NICO and PICCO，the time of improving PCBF，Pm，Cdyn，VCO2，MValv，Pm，PIP，Raw，RSBI，Vd/Vt，and PaO2/FiO2 of the intervention group was severer than those in the control group，and the severety was also more than that of control group which was was significantly different at 72 h（Plt;0.05）. In the PICCO data，the time of decreasing EVWL and PVPI was shorter than the control group，and the decreasing extent was more than the control group，with significant difference at 72 h. But the changes of Apm，CI，and CVP were not significant （Pgt;0.05）. Conclusions In treatment of ARDSexp patients，CBP therapy can induce the PCBC and EVLW，improve pulmonary compliance and MValv，and reduce the mortality rate，while doesn’t influence heart function and the stability of circulation.
Objective To investigate the serumlevel of endothelin-1 ( ET-1) in patients with acute lung injury/acute respiratory distress syndrome ( ALI/ARDS) and its clinical significance. Methods Thirty-one ALI/ARDS patients received mechanical ventilation in ICUand 25 normal subjects were recruited in the study. The patients who died in two weeks fell in death group, and the patients who did not died in two weeks fell in survival group. The serum level of ET-1 measured by EIA method were compared between thepatients with different severity of lung injury [ evaluated by American-European Consensus Conference on ARDS ( AECC) criteria and lung injury score( LIS) ] , and between the patients with different prognosis ( death or survival ) . The correlation was analyzed between the level of ET-1 and clinical parameters.Results The ET-1 level was higher in the ALI/ARDS patients than that in the control subjects [ ( 6. 18 ±4. 48) ng/L vs. ( 2. 68 ±1. 34) ng/L, P lt;0. 05] . There was no significant difference in the patients with different severity [ ALI vs. ARDS, ( 5. 43 ±4. 39) ng/L vs. ( 7. 01 ±4. 51) ng/L, P gt; 0. 05; LIS≤2. 5 vs.LISgt;2. 5, ( 5. 93 ±5. 21) ng/L vs. ( 6. 68 ±2. 76) ng/L, P gt; 0. 05] . The ET-1 level in the death group continued to increase, and higher than that in the survival group on the 5th day [ ( 7. 96 ±3. 30) ng/L vs.( 4. 36 ±3. 29) ng/L, P lt; 0. 05] . The ET-1 level was positively correlated with SIRS, SAPSⅡ and APACHEⅡ ( r = 0. 359, 0. 369 and 0. 426, respectively, P lt; 0. 05 ) , and negatively correlated with PaO2 /FiO2 and AaDO2 ( r = - 0. 286 and - 0. 300, respectively, P lt;0. 05) . Conclusion The measurementof serum ET-1 can help to evaluate the severity and prognosis of ALI/ARDS patients.