Role of proning and positive end-expiratory pressure in COVID-19.
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SUBMITTER: Gandhi KD
PROVIDER: S-EPMC8462021 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description: Not available
| S-EPMC7737587 | biostudies-literature
Project description:BackgroundWe hypothesized that as CARDS may present different pathophysiological features than classic ARDS, the application of high levels of end-expiratory pressure is questionable. Our first aim was to investigate the effects of 5-15 cmH2O of PEEP on partitioned respiratory mechanics, gas exchange and dead space; secondly, we investigated whether respiratory system compliance and severity of hypoxemia could affect the response to PEEP on partitioned respiratory mechanics, gas exchange and dead space, dividing the population according to the median value of respiratory system compliance and oxygenation. Thirdly, we explored the effects of an additional PEEP selected according to the Empirical PEEP-FiO2 table of the EPVent-2 study on partitioned respiratory mechanics and gas exchange in a subgroup of patients.MethodsSixty-one paralyzed mechanically ventilated patients with a confirmed diagnosis of SARS-CoV-2 were enrolled (age 60 [54-67] years, PaO2/FiO2 113 [79-158] mmHg and PEEP 10 [10-10] cmH2O). Keeping constant tidal volume, respiratory rate and oxygen fraction, two PEEP levels (5 and 15 cmH2O) were selected. In a subgroup of patients an additional PEEP level was applied according to an Empirical PEEP-FiO2 table (empirical PEEP). At each PEEP level gas exchange, partitioned lung mechanics and hemodynamic were collected.ResultsAt 15 cmH2O of PEEP the lung elastance, lung stress and mechanical power were higher compared to 5 cmH2O. The PaO2/FiO2, arterial carbon dioxide and ventilatory ratio increased at 15 cmH2O of PEEP. The arterial-venous oxygen difference and central venous saturation were higher at 15 cmH2O of PEEP. Both the mechanics and gas exchange variables significantly increased although with high heterogeneity. By increasing the PEEP from 5 to 15 cmH2O, the changes in partitioned respiratory mechanics and mechanical power were not related to hypoxemia or respiratory compliance. The empirical PEEP was 18 ± 1 cmH2O. The empirical PEEP significantly increased the PaO2/FiO2 but also driving pressure, lung elastance, lung stress and mechanical power compared to 15 cmH2O of PEEP.ConclusionsIn COVID-19 ARDS during the early phase the effects of raising PEEP are highly variable and cannot easily be predicted by respiratory system characteristics, because of the heterogeneity of the disease.
| S-EPMC8674862 | biostudies-literature
Project description:BackgroundInternational guidelines suggest using a higher (> 10 cm H2O) positive end-expiratory pressure (PEEP) in patients with moderate-to-severe ARDS due to COVID-19. However, even if oxygenation generally improves with a higher PEEP, compliance, and Paco2 frequently do not, as if recruitment was small.Research questionIs the potential for lung recruitment small in patients with early ARDS due to COVID-19?Study design and methodsForty patients with ARDS due to COVID-19 were studied in the supine position within 3 days of endotracheal intubation. They all underwent a PEEP trial, in which oxygenation, compliance, and Paco2 were measured with 5, 10, and 15 cm H2O of PEEP, and all other ventilatory settings unchanged. Twenty underwent a whole-lung static CT scan at 5 and 45 cm H2O, and the other 20 at 5 and 15 cm H2O of airway pressure. Recruitment and hyperinflation were defined as a decrease in the volume of the non-aerated (density above -100 HU) and an increase in the volume of the over-aerated (density below -900 HU) lung compartments, respectively.ResultsFrom 5 to 15 cm H2O, oxygenation improved in 36 (90%) patients but compliance only in 11 (28%) and Paco2 only in 14 (35%). From 5 to 45 cm H2O, recruitment was 351 (161-462) mL and hyperinflation 465 (220-681) mL. From 5 to 15 cm H2O, recruitment was 168 (110-202) mL and hyperinflation 121 (63-270) mL. Hyperinflation variably developed in all patients and exceeded recruitment in more than half of them.InterpretationPatients with early ARDS due to COVID-19, ventilated in the supine position, present with a large potential for lung recruitment. Even so, their compliance and Paco2 do not generally improve with a higher PEEP, possibly because of hyperinflation.
| S-EPMC8520168 | biostudies-literature
Project description:RationalePatients with coronavirus disease-19-related acute respiratory distress syndrome (C-ARDS) could have a specific physiological phenotype as compared with those affected by ARDS from other causes (NC-ARDS).ObjectivesTo describe the effect of positive end-expiratory pressure (PEEP) on respiratory mechanics in C-ARDS patients in supine and prone position, and as compared to NC-ARDS. The primary endpoint was the best PEEP defined as the smallest sum of hyperdistension and collapse.MethodsSeventeen patients with moderate-to-severe C-ARDS were monitored by electrical impedance tomography (EIT) and evaluated during PEEP titration in supine (n = 17) and prone (n = 14) position and compared with 13 NC-ARDS patients investigated by EIT in our department before the COVID-19 pandemic.ResultsAs compared with NC-ARDS, C-ARDS exhibited a higher median best PEEP (defined using EIT as the smallest sum of hyperdistension and collapse, 12 [9, 12] vs. 9 [6, 9] cmH2O, p < 0.01), more collapse at low PEEP, and less hyperdistension at high PEEP. The median value of the best PEEP was similar in C-ARDS in supine and prone position: 12 [9, 12] vs. 12 [10, 15] cmH2O, p = 0.59. The response to PEEP was also similar in C-ARDS patients with higher vs. lower respiratory system compliance.ConclusionAn intermediate PEEP level seems appropriate in half of our C-ARDS patients. There is no solid evidence that compliance at low PEEP could predict the response to PEEP.
| S-EPMC7719729 | biostudies-literature
Project description: Not available
| S-EPMC7365366 | biostudies-literature
Project description:BackgroundPositive end-expiratory pressure (PEEP) has been demonstrated to decrease ventilator-induced lung injury in patients under mechanical ventilation (MV) for acute respiratory failure. Recently, some studies have proposed some beneficial effects of PEEP in ventilated patients without lung injury. The influence of PEEP on respiratory mechanics in children is not well known. Our aim was to determine the effects on respiratory mechanics of setting PEEP at 5 cmH2O in anesthetized healthy children.MethodsPatients younger than 15 years old without history of lung injury scheduled for elective surgery gave informed consent and were enrolled in the study. After usual care for general anesthesia, patients were placed on volume controlled MV. Two sets of respiratory mechanics studies were performed using inspiratory and expiratory breath hold, with PEEP 0 and 5 cmH2O. The maximum inspiratory and expiratory flow (QI and QE) as well as peak inspiratory pressure (PIP), plateau pressure (PPL) and total PEEP (tPEEP) were measured. Respiratory system compliance (CRS), inspiratory and expiratory resistances (RawI and RawE) and time constants (KTI and KTE) were calculated. Data were expressed as median and interquartile range (IQR). Wilcoxon sign test and Spearman's analysis were used. Significance was set at P < 0.05.ResultsWe included 30 patients, median age 39 (15-61.3) months old, 60% male. When PEEP increased, PIP increased from 12 (11,14) to 15.5 (14,18), and CRS increased from 0.9 (0.9,1.2) to 1.2 (0.9,1.4) mL·kg- 1·cmH2O- 1; additionally, when PEEP increased, driving pressure decreased from 6.8 (5.9,8.1) to 5.8 (4.7,7.1) cmH2O, and QE decreased from 13.8 (11.8,18.7) to 11.7 (9.1,13.5) L·min- 1 (all P < 0.01). There were no significant changes in resistance and QI.ConclusionsAnalysis of respiratory mechanics in anesthetized healthy children shows that PEEP at 5 cmH2O places the respiratory system in a better position in the P/V curve. A better understanding of lung mechanics may lead to changes in the traditional ventilatory approach, limiting injury associated with MV.
| S-EPMC6201576 | biostudies-literature
Project description:Purpose of reviewThe purpose of this review is to summarize the role of lung ultrasound and diaphragm ultrasound in guiding ventilator settings with an emphasis on positive end-expiratory pressure (PEEP). Recent advances for using ultrasound to assess the effects of PEEP on the lungs and diaphragm are discussed.Recent findingsLung ultrasound can accurately diagnose the cause of acute respiratory failure, including acute respiratory distress syndrome and can identify focal and nonfocal lung morphology in these patients. This is essential in determining optimal ventilator strategy and PEEP level. Assessment of the effect of PEEP on lung recruitment using lung ultrasound is promising, especially in the perioperative setting. Diaphragm ultrasound can monitor the effects of PEEP on the diaphragm, but this needs further validation. In patients with an acute exacerbation of chronic obstructive pulmonary disease, diaphragm ultrasound can be used to predict noninvasive ventilation failure. Lung and diaphragm ultrasound can be used to predict weaning outcome and accurately diagnose the cause of weaning failure.SummaryLung and diaphragm ultrasound are useful for diagnosing the cause of respiratory failure and subsequently setting the ventilator including PEEP. Effects of PEEP on lung and diaphragm can be monitored using ultrasound.
| S-EPMC10962429 | biostudies-literature
Project description:Lung recruitment maneuvers followed by an individually titrated positive end-expiratory pressure (PEEP) are the key components of the open lung ventilation strategy in acute respiratory distress syndrome (ARDS). The staircase recruitment maneuver is a step-by-step increase in PEEP followed by a decremental PEEP trial. The duration of each step is usually 2 minutes without physiologic rationale.In this prospective study, we measured the dynamic end-expiratory lung volume changes (?EELV) during an increase and decrease in PEEP to determine the optimal duration for each step. PEEP was progressively increased from 5 to 40 cmH2O and then decreased from 40 to 5 cmH2O in steps of 5 cmH2O every 2.5 minutes. The dynamic of ?EELV was measured by direct spirometry as the difference between inspiratory and expiratory tidal volumes over 2.5 minutes following each increase and decrease in PEEP. ?EELV was separated between the expected increased volume, calculated as the product of the respiratory system compliance by the change in PEEP, and the additional volume.Twenty-six early onset moderate or severe ARDS patients were included. Data are expressed as median [25th-75th quartiles]. During the increase in PEEP, the expected increased volume was achieved within 2[2-2] breaths. During the decrease in PEEP, the expected decreased volume was achieved within 1 [1-1] breath, and 95 % of the additional decreased volume was achieved within 8 [2-15] breaths. Completion of volume changes in 99 % of both increase and decrease in PEEP events required 29 breaths.In early ARDS, most of the ?EELV occurs within the first minute, and change is completed within 2 minutes, following an increase or decrease in PEEP.
| S-EPMC4574463 | biostudies-literature
Project description:BACKGROUND:In ARDS patients, changes in respiratory mechanical properties and ventilatory settings can cause incomplete lung deflation at end-expiration. Both can promote dynamic hyperinflation and intrinsic positive end-expiratory pressure (PEEP). The aim of this study was to investigate, in a large population of ARDS patients, the presence of intrinsic PEEP, possible associated factors (patients' characteristics and ventilator settings), and the effects of two different external PEEP levels on the intrinsic PEEP. METHODS:We made a secondary analysis of published data. Patients were ventilated with a tidal volume of 6-8?mL/kg of predicted body weight, sedated, and paralyzed. After a recruitment maneuver, a PEEP trial was run at 5 and 15 cmH2O, and partitioned mechanics measurements were collected after 20?min of stabilization. Lung computed tomography scans were taken at 5 and 45 cmH2O. Patients were classified into two groups according to whether or not they had intrinsic PEEP at the end of an expiratory pause. RESULTS:We enrolled 217 sedated, paralyzed patients: 87 (40%) had intrinsic PEEP with a median of 1.1 [1.0-2.3] cmH2O at 5 cmH2O of PEEP. The intrinsic PEEP significantly decreased with higher PEEP (1.1 [1.0-2.3] vs 0.6 [0.0-1.0] cmH2O; p?<?0.001). The applied tidal volume was significantly lower (480 [430-540] vs 520 [445-600] mL at 5 cmH2O of PEEP; 480 [430-540] vs 510 [430-590] mL at 15 cmH2O) in patients with intrinsic PEEP, while the respiratory rate was significantly higher (18 [15-20] vs 15 [13-19] bpm at 5 cmH2O of PEEP; 18 [15-20] vs 15 [13-19] bpm at 15 cmH2O). At both PEEP levels, the total airway resistance and compliance of the respiratory system were not different in patients with and without intrinsic PEEP. The total lung gas volume and lung recruitability were also not different between patients with and without intrinsic PEEP (respectively 961 [701-1535] vs 973 [659-1433] mL and 15 [0-32] % vs 22 [0-36] %). CONCLUSIONS:In sedated, paralyzed ARDS patients without a known obstructive disease, the amount of intrinsic PEEP during lung-protective ventilation is negligible and does not influence respiratory mechanical properties.
| S-EPMC6880369 | biostudies-literature
Project description:IntroductionHealthy piglets ventilated with no positive end-expiratory pressure (PEEP) and with tidal volume (VT) close to inspiratory capacity (IC) develop fatal pulmonary oedema within 36 h. In contrast, those ventilated with high PEEP and low VT, resulting in the same volume of gas inflated (close to IC), do not. If the real threat to the blood-gas barrier is lung overinflation, then a similar damage will occur with the two settings. If PEEP only hydrostatically counteracts fluid filtration, then its removal will lead to oedema formation, thus revealing the deleterious effects of overinflation.MethodsFollowing baseline lung computed tomography (CT), five healthy piglets were ventilated with high PEEP (volume of gas around 75% of IC) and low VT (25% of IC) for 36 h. PEEP was then suddenly zeroed and low VT was maintained for 18 h. Oedema was diagnosed if final lung weight (measured on a balance following autopsy) exceeded the initial one (CT).ResultsAnimals were ventilated with PEEP 18 ± 1 cmH2O (volume of gas 875 ± 178 ml, 89 ± 7% of IC) and VT 213 ± 10 ml (22 ± 5% of IC) for the first 36 h, and with no PEEP and VT 213 ± 10 ml for the last 18 h. On average, final lung weight was not higher, and actually it was even lower, than the initial one (284 ± 62 vs. 347 ± 36 g; P = 0.01).ConclusionsHigh PEEP (and low VT) do not merely impede fluid extravasation but rather preserve the integrity of the blood-gas barrier in healthy lungs.
| S-EPMC4056428 | biostudies-literature