The Effect of the Pressure–Volume Curve for Positive End-Expiratory Pressure Titration on Clinical Outcomes in Acute Respiratory Distress Syndrome

2013 ◽  
Vol 29 (6) ◽  
pp. 348-356 ◽  
Author(s):  
J. Steven Hata ◽  
Kei Togashi ◽  
Avinash B. Kumar ◽  
Linda D. Hodges ◽  
Eric F. Kaiser ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Controlled Trials ◽  
Cochrane Central Register ◽  
Positive End Expiratory Pressure ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Ventilator Management

Purpose Methods to optimize positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS) remain controversial despite decades of research. The pressure–volume curve (PVC), a graphical ventilator relationship, has been proposed for prescription of PEEP in ARDS. Whether the use of PVC’s improves survival remains unclear. Methods In this systematic review, we assessed randomized controlled trials (RCTs) comparing PVC-guided treatment with conventional PEEP management on survival in ARDS based on the search of the National Library of Medicine from January 1, 1960, to January 1, 2010, and the Cochrane Central Register of Controlled Trials. Three RCTs were identified with a total of 185 patients, 97 with PVC-guided treatment and 88 with conventional PEEP management. Results The PVC-guided PEEP was associated with an increased probability of 28-day or hospital survival (odds ratio [OR] 2.7, 95% confidence interval [CI] 1.5, 4.9) using a random-effects model without significant heterogeneity ( I2 test: P = .75). The PVC-guided ventilator support was associated with reduced cumulative risk of mortality (−0.24 (95% CI −0.38, −0.11). The PVC-managed patients received greater PEEP (standardized mean difference [SMD] 5.7 cm H2O, 95% CI 2.4, 9.0) and lower plateau pressures (SMD −1.2 cm H2O, 95% CI −2.2, −0.2), albeit with greater hypercapnia with increased arterial pCO2 (SMD 8 mm Hg, 95% CI 2, 14). Weight-adjusted tidal volumes were significantly lower in PVC-guided than conventional ventilator management (SMD 2.6 mL/kg, 95% CI −3.3, −2.0). Conclusion This analysis supports an association that ventilator management guided by the PVC for PEEP management may augment survival in ARDS. Nonetheless, only 3 randomized trials have addressed the question, and the total number of patients remains low. Further outcomes studies appear required for the validation of this methodology.

Lung volumes and alveolar expansion pattern in immature rabbits treated with serum-diluted surfactant

2004 ◽  
Vol 97 (4) ◽  
pp. 1408-1413 ◽  
Author(s):  
Yongmei Xu ◽  
Tsutomu Kobayashi ◽  
Xiaoguang Cui ◽  
Keisuke Ohta ◽  
Chiharu Kabata ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Ringer Solution ◽  
Natural Surfactant ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Expansion Pattern

In acute respiratory distress syndrome, mechanical ventilation often induces alveolar overdistension aggravating the primary insult. To examine the mechanism of overdistension, surfactant-deficient immature rabbits were anesthetized with pentobarbital sodium, and their lungs were treated with serum-diluted modified natural surfactant (porcine lung extract; 2 mg/ml, 10 ml/kg). By mechanical ventilation with a peak inspiration pressure of 22.5 cmH2O, the animals had a tidal volume of 14.7 ml/kg (mean), when 2.5 cmH2O positive end-expiratory pressure was added. This volume was similar to that in animals treated with nondiluted modified natural surfactant (24 mg/ml in Ringer solution, 10 ml/kg). However, the lungs fixed at 10 cmH2O on the deflation limbs of the pressure-volume curve had the largest alveolar/alveolar duct profiles (≥48,000 μm2), accounting for 38% of the terminal air spaces, and the smallest (<6,000 μm2), accounting for 31%. These values were higher than those in animals treated with nondiluted modified natural surfactant ( P < 0.05). We conclude that administration of serum-diluted surfactant to immature neonatal lungs leads to patchy overdistension of terminal air spaces, similar to the expansion pattern that may be seen after dilution of endogenous surfactant with proteinaceous edema fluid in acute respiratory distress syndrome.

Letters to the Editor

1998 ◽  
Vol 85 (5) ◽  
pp. 1998-2000
Author(s):  
Hans-G. Sonander
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Goodness Of Fit ◽  
Distress Syndrome ◽  
Letters To The Editor ◽  
Mechanically Ventilated ◽  
Pulmonary Pressure ◽  
Volume Curve ◽  
Pressure Volume Curve

The following is the abstract of the article discussed in the subsequent letter: Venegas, José G., R. Scott Harris, and Brett A. Simon. A comprehensive equation for the pulmonary pressure-volume curve. J. Appl. Physiol. 84(1): 389–395, 1998.—Quantification of pulmonary pressure-volume (P-V) curves is often limited to calculation of specific compliance at a given pressure or the recoil pressure (P) at a given volume (V). These parameters can be substantially different depending on the arbitrary pressure or volume used in the comparison and may lead to erroneous conclusions. We evaluated a sigmoidal equation of the form, V = a + b[1 +  e −(P− c)/ d ]−1, for its ability to characterize lung and respiratory system P-V curves obtained under a variety of conditions including normal and hypocapnic pneumoconstricted dog lungs ( n = 9), oleic acid-induced acute respiratory distress syndrome ( n = 2), and mechanically ventilated patients with acute respiratory distress syndrome ( n = 10). In this equation, a corresponds to the V of a lower asymptote, b to the V difference between upper and lower asymptotes, c to the P at the true inflection point of the curve, and d to a width parameter proportional to the P range within which most of the V change occurs. The equation fitted equally well inflation and deflation limbs of P-V curves with a mean goodness-of-fit coefficient ( R 2) of 0.997 ± 0.02 (SD). When the data from all analyzed P-V curves were normalized by the best-fit parameters and plotted as (V −  a)/ b vs. (P −  c)/ d, they collapsed into a single and tight relationship ( R 2 = 0.997). These results demonstrate that this sigmoidal equation can fit with excellent precision inflation and deflation P-V curves of normal lungs and of lungs with alveolar derecruitment and/or a region of gas trapping while yielding robust and physiologically useful parameters.

scholarly journals Effect of lung recruitment and titrated positive end-expiratory pressure (PEEP) versus low PEEP on patients with moderate–severe acute respiratory distress syndrome: a systematic review and meta-analysis of randomized controlled trials

2019 ◽  
Vol 13 ◽  
pp. 175346661985822 ◽  
Author(s):  
Xi Zheng ◽  
Yijia Jiang ◽  
Huimiao Jia ◽  
Wenliang Ma ◽  
Yue Han ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Length Of Stay ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Randomized Controlled Trials ◽  
Distress Syndrome ◽  
Controlled Trials ◽  
Positive End Expiratory Pressure ◽  
Icu Mortality ◽  
Randomized Controlled

Background: Setting a positive end-expiratory pressure (PEEP) on patients with acute respiratory distress syndrome (ARDS) receiving mechanical ventilation has been an issue of great contention. Therefore, we aimed to determine effects of lung recruitment maneuver (RM) and titrated PEEP versus low PEEP on adult patients with moderate–severe ARDS. Methods: Data sources and study selection proceeded as follows: PubMed, Ovid, EBSCO, and Cochrane Library databases were searched from 2003 to May 2018. Original clinical randomized controlled trials which met the eligibility criteria were included. To compare the prognosis between the titrated PEEP and low PEEP groups on patients with moderate–severe ARDS (PaO2/FiO2 < 200 mmHg). Heterogeneity was quantified through the I2 statistic. Egger’s test and funnel plots were used to assess publication bias. Results: No difference was found in 28-day mortality and ICU mortality (OR = 0.97, 95% CI (0.61–1.52), p = 0.88; OR = 1.14, 95% CI (0.91–1.43), p = 0.26, respectively). Only ventilator-free days, length of stay in the ICU, length of stay in hospital, and incidence of barotrauma could be systematically reviewed owing to bias and extensive heterogeneity. Conclusion: No difference was observed in the RM between the titrated PEEP and the low PEEP in 28-day mortality and ICU mortality on patients with moderate–severe ARDS.

Permissive Hypercapnia with and without Expiratory Washout in Patients with Severe Acute Respiratory Distress Syndrome 

1997 ◽  
Vol 87 (1) ◽  
pp. 6-17 ◽  
Author(s):  
Pierre Kalfon ◽  
G. S. Umamaheswara Rao ◽  
Lluis Gallart ◽  
Louis Puybasset ◽  
Pierre Coriat ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Injury Severity ◽  
Distress Syndrome ◽  
Permissive Hypercapnia ◽  
Positive End Expiratory Pressure ◽  
Ventilatory Strategy ◽  
Volume Curve

Background Permissive hypercapnia is a ventilatory strategy aimed at avoiding lung volutrauma in patients with severe acute respiratory distress syndrome (ARDS). Expiratory washout (EWO) is a modality of tracheal gas insufflation that enhances carbon dioxide removal during mechanical ventilation by reducing dead space. The goal of this prospective study was to determine the efficacy of EWO in reducing the partial pressure of carbon dioxide (PaCO2) in patients with severe ARDS treated using permissive hypercapnia. Methods Seven critically ill patients with severe ARDS (lung injury severity score, 3.1 +/- 0.3) and no contraindications for permissive hypercapnia were studied. On the first day, hemodynamic and respiratory parameters were measured and the extent of lung hyperdensities was assessed using computed tomography. A positive end-expiratory pressure equal to the opening pressure identified on the pressure-volume curve was applied. Tidal volume was reduced until a plateau airway pressure of 25 cm H2O was reached. On the second day, after implementation of permissive hypercapnia, EWO was instituted at a flow of 15 l/min administered during the entire expiratory phase into the trachea through the proximal channel of an endotracheal tube using a ventilator equipped with a special flow generator. Cardiorespiratory parameters were studied under three conditions: permissive hypercapnia, permissive hypercapnia with EWO, and permissive hypercapnia. Results During permissive hypercapnia, EWO decreased PaCO2 from 76 +/- 4 mmHg to 53 +/- 3 mmHg (-30%; P &lt; 0.0001), increased pH from 7.20 +/- 0.03 to 7.34 +/- 0.04 (P &lt; 0.0001), and increased PaO2 from 205 +/- 28 to 296 +/- 38 mmHg (P &lt; 0.05). The reduction in PaCO2 was accompanied by an increase in end-inspiratory plateau pressure from 26 +/- 1 to 32 +/- 2 cm H2O (P = 0.001). Expiratory washout also decreased cardiac index from 4.6 +/- 0.4 to 3.7 +/- 0.3 l.min-1.m-2 (P &lt; 0.01), mean pulmonary arterial pressure from 28 +/- 2 to 25 +/- 2 mmHg (P &lt; 0.01), and true pulmonary shunt from 47 +/- 2 to 36 +/- 3% (P &lt; 0.01). Conclusions Expiratory washout is an effective and easy-to-use ventilatory modality to reduce PaCO2 and increase pH during permissive hypercapnia. However, it significantly increases airway pressures and lung volume through expiratory flow limitation, reexposing some patients to a risk of lung volutrauma if the extrinsic positive end-expiratory pressure is not substantially reduced.

Alveolar Recruitment in Pulmonary and Extrapulmonary Acute Respiratory Distress Syndrome

2007 ◽  
Vol 106 (2) ◽  
pp. 212-217 ◽  
Author(s):  
Arnaud W. Thille ◽  
Jean-Christophe M. Richard ◽  
Salvatore M. Maggiore ◽  
V Marco Ranieri ◽  
Laurent Brochard
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Tidal Volume ◽  
Distress Syndrome ◽  
Alveolar Recruitment ◽  
High Peep ◽  
Static Compliance ◽  
Volume Curve ◽  
Pressure Volume Curve

Background Alveolar recruitment in response to positive end-expiratory pressure (PEEP) may differ between pulmonary and extrapulmonary acute respiratory distress syndrome (ARDS), and alveolar recruitment values may differ when measured by pressure-volume curve compared with static compliance. Methods The authors compared PEEP-induced alveolar recruitment in 71 consecutive patients identified in a database. Patients were classified as having pulmonary, extrapulmonary, or mixed/uncertain ARDS. Pressure-volume curves with and without PEEP were available for all patients, and pressure-volume curves with two PEEP levels were available for 44 patients. Static compliance was calculated as tidal volume divided by pressure change for tidal volumes of 400 and 700 ml. Recruited volume was measured at an elastic pressure of 15 cm H2O. Results Volume recruited by PEEP (10 +/- 3 cm H2O) was 223 +/- 111 ml in the pulmonary ARDS group (29 patients), 206 +/- 164 ml in the extrapulmonary group (16 patients), and 242 +/- 176 ml in the mixed/uncertain group (26 patients) (P = 0.75). At high PEEP (14 +/- 2 cmH2O, 44 patients), recruited volumes were also similar (P = 0.60). With static compliance, recruitment was markedly underestimated and was dependent on tidal volume (226 +/- 148 ml using pressure-volume curve, 95 +/- 185 ml for a tidal volume of 400 ml, and 23 +/- 169 ml for 700 ml; P &lt; 0.001). Conclusion In a large sample of patients, classification of ARDS was uncertain in more than one third of patients, and alveolar recruitment was similar in pulmonary and extrapulmonary ARDS. PEEP levels should not be determined based on cause of ARDS.

Relationship between pressure-volume curve and markers for collagen turn-over in early acute respiratory distress syndrome

2006 ◽  
Vol 32 (3) ◽  
pp. 413-420 ◽  
Author(s):  
Alexandre Demoule ◽  
François Decailliot ◽  
Bjorn Jonson ◽  
Christo Christov ◽  
Bernard Maitre ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
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