Lung volumes and lung volume recruitment in ARDS: a comparison between supine and prone position.
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SUBMITTER: Aguirre-Bermeo H
PROVIDER: S-EPMC5812959 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundRecent reports of patients with severe, late-stage COVID-19 ARDS with reduced respiratory system compliance described paradoxical decreases in plateau pressure and increases in respiratory system compliance in response to anterior chest wall loading. We aimed to assess the effect of chest wall loading during supine and prone position in ill patients with COVID-19-related ARDS and to investigate the effect of a low or normal baseline respiratory system compliance on the findings.MethodsThis is a single-center, prospective, cohort study in the intensive care unit of a COVID-19 referral center. Consecutive mechanically ventilated, critically ill patients with COVID-19-related ARDS were enrolled and classified as higher (≥ 40 ml/cmH2O) or lower respiratory system compliance (< 40 ml/cmH2O). The study included four steps, each lasting 6 h: Step 1, supine position, Step 2, 10-kg continuous chest wall compression (supine + weight), Step 3, prone position, Step 4, 10-kg continuous chest wall compression (prone + weight). The mechanical properties of the respiratory system, gas exchange and alveolar dead space were measured at the end of each step.ResultsTotally, 40 patients were enrolled. In the whole cohort, neither oxygenation nor respiratory system compliance changed between supine and supine + weight; both increased during prone positioning and were unaffected by chest wall loading in the prone position. Alveolar dead space was unchanged during all the steps. In 16 patients with reduced compliance, PaO2/FiO2 significantly increased from supine to supine + weight and further with prone and prone + weight (107 ± 15.4 vs. 120 ± 18.5 vs. 146 ± 27.0 vs. 159 ± 30.4, respectively; p < 0.001); alveolar dead space decreased from both supine and prone position after chest wall loading, and respiratory system compliance significantly increased from supine to supine + weight and from prone to prone + weight (23.9 ± 3.5 vs. 30.9 ± 5.7 and 31.1 ± 5.7 vs. 37.8 ± 8.7 ml/cmH2O, p < 0.001). The improvement was higher the lower the baseline compliance.ConclusionsUnlike prone positioning, chest wall loading had no effects on respiratory system compliance, gas exchange or alveolar dead space in an unselected cohort of critically ill patients with C-ARDS. Only patients with a low respiratory system compliance experienced an improvement, with a higher response the lower the baseline compliance.
| S-EPMC9470071 | biostudies-literature
Project description:PURPOSE:To evaluate the effect of the positioning from the supine position (SP) to the prone position (PP) on the diaphragm activity in ventilated patients; using the ultrasound (US) imaging. METHODS:A cross-sectional comparative study before/after PP was conducted on 40 ICU patients over 18 years who received invasive ventilation (IV) for at least 48 h. The considered ventilator modes were: assisted control volume with a low trigger flow (between -?2 and 2 L/mn) and pressure support mode. US diaphragmatic assessments were performed at SP and at 60 min of PP. Both End-inspiratory and End-expiratory diameters (EID/EED) were taken at 3 levels of axillary lines and determined by the average values of multiple measures. Diaphragmatic thickening fraction (DTF) was calculated as: DTF?=?(EID?-?EED/EED)?×?100. Pairing and ANOVA tests were used for comparisons. RESULTS:Forty ventilated patients (42 years of median age) at 4 days [2-7] of median duration of ventilation were examined during the two positions: SP versus PP. EID decreased from the SP to the PP (2.8 mm in SP vs. 2.4 mm in PP, p?=?0.001). No difference was showed regarding the expiratory thickness. Overall, DTF didn't change in PP (37.4 vs. 42.05%, p?=?0.36). When the patient was placed in PP, the best DTF value was showed at the posterior part of diaphragm (posterior: 45%, median: 31% and anterior: 38%, p?=?0.049). CONCLUSION:The ventral placement in ventilated patients reduced end-inspiratory diameter and tended to decrease DTF. In PP, the best contractile activity was detected at the posterior region of diaphragm.
| S-EPMC7459156 | biostudies-literature
Project description:BACKGROUND:Hemodynamic response to prone position (PP) has never been studied in a large series of patients with acute respiratory distress syndrome (ARDS). The primary aim of this study was to estimate the rate of PP sessions associated with cardiac index improvement. Secondary objective was to describe hemodynamic response to PP and during the shift from PP to supine position. METHODS:The study was a single-center retrospective observational study, performed on ARDS patients, undergoing at least one PP session under monitoring by transpulmonary thermodilution. PP sessions performed more than 10 days after ARDS onset, or with any missing cardiac index measurements before (T1), at the end (T3), and after the PP session (T4) were excluded. Changes in hemodynamic parameters during PP were tested after statistical adjustment for volume of fluid challenges, vasopressor and dobutamine dose at each time point to take into account therapeutic changes during PP sessions. RESULTS:In total, 107 patients fulfilled the inclusion criteria, totalizing 197 PP sessions. Changes in cardiac index between T1 and T2 (early response to PP) and between T1 and T3 (late response to PP) were significantly correlated (R2?=?0.42, p?<?0.001) with a concordance rate amounting to 85%. Cardiac index increased significantly between T1 and T3 in 49 sessions (25% [95% confidence interval (CI95%) 18-32%]), decreased significantly in 46 (23% [CI95% 16-31%]), and remained stable in 102 (52% [CI95% 45-59%]). Global end-diastolic volume index (GEDVI) increased slightly but significantly from 719?±?193 mL m-2 at T1 to 757?±?209 mL m-2 at T3 and returned to baseline values at T4. Cardiac index and oxygen delivery decreased slightly but significantly from T3 to T4, without detectable increase in lactate level. Patients who increased their cardiac index during PP had significantly lower CI, GEDVI, global ejection fraction at T1, and received significantly more fluids than patients who did not. CONCLUSION:PP is associated with an increase in cardiac index in 18% to 32% of all PP sessions and a sustained increase in GEDVI reversible after return to supine position. Return from prone to supine position is associated with a slight hemodynamic impairment.
| S-EPMC6286298 | biostudies-literature
Project description:IntroductionTo compare the efficacy and safety of percutaneous nephrolithotomy (PCNL) in the oblique supine position (OSP) and the prone position (PP).AimTo perform a systematic review and meta-analysis to evaluate the efficacy and safety of OSP versus PP for PCNL.Material and methodsA systematic literature search of PubMed, Ovid, SCOPUS, and citation lists was conducted to identify eligible comparative studies up to November 2022. All studies comparing OSP versus PP for PCNL were included. Statistical analysis was performed with the Collaboration's Review Manager (RevMan) 5.4 software.ResultsOverall, eight studies were included involving 1185 patients (OSP = 634; PP = 551). There were no statistically significant differences between OSP and PP in age (WMD = -0.95 years; 95% CI: -2.12 to 0.21; p = 0.83) or proportion of male patients (OR = 0.02; 95% CI: -0.03 to 0.08; p = 0.43). We found that OSP was performed more frequently for smaller stone size and patients with higher BMI (WMD = -0.1 cm, 95% CI: -0.18 to -0.02; p = 0.01) and patients with higher BMI (WMD = 0.66 kg/m2; 95% CI: 0.29 to 1.03; p = 0.0005). The operation time was shorter in OSP than PP (WMD = -14 min; 95% CI: -27.00 to -1.00; p = 0.03). The reduction of hemoglobin was lower in OSP than PP (WMD = -0.39 g/dl; 95% CI: -0.60 to -0.13; p = 0.03). There was no significant difference in stone-free rate and hospitalization between the two groups (OR = 1.32; 95% CI: 0.98 to 1.78; p = 0.07; WMD = -5.99 h; 95% CI: -17.15 to 5.16; p = 0.29). The overall complications were fewer in OSP than in PP (OR = 0.59; 95% CI: 0.43 to 0.81; p = 0.001), but no difference was observed between the positions with regard to the major complications (Clavien-Dindo score ≥ 3) (OR = 0.76; 95% CI: 0.43 to 1.34; p = 0.35).ConclusionsOSP showed non-inferior stone-free rate, blood loss, and hospitalization compared with PP. OSP may be superior in terms of operative time and complications than PP.
| S-EPMC10481440 | biostudies-literature
Project description:In ARDS patients, the change from supine to prone position generates a more even distribution of the gas-tissue ratios along the dependent-nondependent axis and a more homogeneous distribution of lung stress and strain. The change to prone position is generally accompanied by a marked improvement in arterial blood gases, which is mainly due to a better overall ventilation/perfusion matching. Improvement in oxygenation and reduction in mortality are the main reasons to implement prone position in patients with ARDS. The main reason explaining a decreased mortality is less overdistension in non-dependent lung regions and less cyclical opening and closing in dependent lung regions. The only absolute contraindication for implementing prone position is an unstable spinal fracture. The maneuver to change from supine to prone and vice versa requires a skilled team of 4-5 caregivers. The most frequent adverse events are pressure sores and facial edema. Recently, the use of prone position has been extended to non-intubated spontaneously breathing patients affected with COVID-19 ARDS. The effects of this intervention on outcomes are still uncertain.
| S-EPMC7652705 | biostudies-literature
Project description:No clinical study has compared lung or lobe volumes on computed tomography (CT) between the supine and standing positions in patients with idiopathic lung fibrosis (IPF). This study aimed to compare lung and lobe volumes between the supine and standing positions and evaluate the correlations between the supine/standing lung volumes on CT and pulmonary function in patients with IPF. Twenty-three patients with IPF underwent a pulmonary function test and both low-dose conventional (supine position) and upright CT (standing position) during inspiration breath-holds. The volumes of the total lungs and lobes were larger in the standing than in the supine position in patients with IPF (all p < 0.05). Spearman's correlation coefficients between total lung volumes on chest CT in supine/standing positions and vital capacity (VC) or forced VC (FVC) were 0.61/0.79 or 0.64/0.80, respectively. CT-based volumes on upright CT were better correlated with VC and FVC than those on supine CT. Lung and lobe volumes in the standing position may be useful biomarkers to assess disease severity or therapeutic effect in patients with IPF.
| S-EPMC9653373 | biostudies-literature
Project description:Positron emission tomography (PET) is typically performed in the supine position. However, breast magnetic resonance imaging (MRI) is performed in prone, as this improves visibility of deep breast tissues. With the emergence of hybrid scanners that integrate molecular information from PET and functional information from MRI, it is of great interest to determine if the prognostic utility of prone PET is equivalent to supine. We compared PERCIST (PET Response Criteria in Solid Tumors) measurements between prone and supine FDG-PET in patients with breast cancer and the effect of orientation on predicting pathologic complete response (pCR). In total, 47 patients were enrolled and received up to 6 cycles of neoadjuvant therapy. Prone and supine FDG-PET were performed at baseline (t0 ; n = 46), after cycle 1 (t1 ; n = 1) or 2 (t2 ; n = 10), or after all neoadjuvant therapy (t3 ; n = 19). FDG uptake was quantified by maximum and peak standardized uptake value (SUV) with and without normalization to lean body mass; that is, SUVmax , SUVpeak , SULmax , and SULpeak . PERCIST measurements were performed for each paired baseline and post-treatment scan. Receiver operating characteristic analysis for the prediction of pCR was performed using logistic regression that included age and tumor size as covariates. SUV and SUL metrics were significantly different between orientation (P < .001), but were highly correlated (P > .98). Importantly, no differences were observed with the PERCIST measurements (P > .6). Overlapping 95% confidence intervals for the receiver operating characteristic analysis suggested no difference at predicting pCR. Therefore, prone and supine PERCIST in this data set were not statistically different.
| S-EPMC7289244 | biostudies-literature
Project description:Study objectiveTo review the effects of prone position and supine position on oxygenation parameters in patients with Coronavirus Disease 2019 (COVID-19).DesignSystematic review and meta-analysis of non-randomized trials.PatientsDatabases of EMBASE, MEDLINE and CENTRAL were systematically searched from its inception until March 2021.InterventionsCOVID-19 patients being positioned in the prone position either whilst awake or mechanically ventilated.MeasurementsPrimary outcomes were oxygenation parameters (PaO₂/FiO₂ ratio, PaCO₂, SpO₂). Secondary outcomes included the rate of intubation and mortality rate.ResultsThirty-five studies (n = 1712 patients) were included in this review. In comparison to the supine group, prone position significantly improved the PaO₂/FiO₂ ratio (study = 13, patients = 1002, Mean difference, MD 52.15, 95% CI 37.08 to 67.22; p < 0.00001) and SpO₂ (study = 11, patients = 998, MD 4.17, 95% CI 2.53 to 5.81; p ≤0.00001). Patients received prone position were associated with lower incidence of mortality (study = 5, patients = 688, Odd ratio, OR 0.44, 95% CI 0.24 to 0.80; p = 0.007). No significant difference was noted in the incidence of intubation rate (study = 5, patients = 626, OR 1.20, 95% CI 0.77 to 1.86; p = 0.42) between the supine and prone groups.ConclusionOur meta-analysis demonstrated that prone position improved PaO₂/FiO₂ ratio with better SpO₂ than supine position in COVID-19 patients. Given the limited number of studies with small sample size and substantial heterogeneity of measured outcomes, further studies are warranted to standardize the regime of prone position to improve the certainty of evidence. PROSPERO Registration: CRD42021234050.
| S-EPMC8216875 | biostudies-literature
Project description:BackgroundIn acute respiratory distress syndrome (ARDS) patients, it has recently been proposed to set positive end-expiratory pressure (PEEP) by targeting end-expiratory transpulmonary pressure. This approach, which relies on the measurement of absolute esophageal pressure (Pes), has been used in supine position (SP) and has not been investigated in prone position (PP). Our purposes were to assess Pes-guided strategy to set PEEP in SP and in PP as compared with a PEEP/FIO2 table and to explore the early (1 h) and late (16 h) effects of PP on lung and chest wall mechanics.ResultsWe performed a prospective, physiologic study in two ICUs in university hospitals on ARDS patients with PaO2/FIO2 < 150 mmHg. End-expiratory Pes (Pes,ee) was measured in static (zero flow) condition. Patients received PEEP set according to a PEEP/FIO2 table then according to the Pes-guided strategy targeting a positive (3 ± 2 cmH2O) static end-expiratory transpulmonary pressure in SP. Then, patients were turned to PP and received same amount of PEEP from PEEP/FIO2 table then Pes-guided strategy. Respiratory mechanics, oxygenation and end-expiratory lung volume (EELV) were measured after 1 h of each PEEP in each position. For the rest of the 16-h PP session, patients were randomly allocated to either PEEP strategy with measurements done at the end. Thirty-eight ARDS patients (27 male), mean ± SD age 63 ± 13 years, were included. There were 33 primary ARDS and 26 moderate ARDS. PaO2/FIO2 ratio was 120 ± 23 mmHg. At same PEEP/FIO2 table-related PEEP, Pes,ee averaged 9 ± 4 cmH2O in both SP and PP (P = 0.88). With PEEP/FIO2 table and Pes-guided strategy, PEEP was 10 ± 2 versus 12 ± 4 cmH2O in SP and 10 ± 2 versus 12 ± 5 cmH2O in PP (PEEP strategy effect P = 0.05, position effect P = 0.96, interaction P = 0.96). With the Pes-guided strategy, chest wall elastance increased regardless of position. Lung elastance and transpulmonary driving pressure decreased in PP, with no effect of PEEP strategy. Both PP and Pes-guided strategy improved oxygenation without interaction. EELV did not change with PEEP strategy. At the end of PP session, respiratory mechanics did not vary but EELV and PaO2/FIO2 increased while PaCO2 decreased.ConclusionsThere was no impact of PP on Pes measurements. PP had an immediate improvement effect on lung mechanics and a late lung recruitment effect independent of PEEP strategy.
| S-EPMC6134472 | biostudies-literature
Project description:Background and purposeDose effects of intrafraction motion during prone prostate radiotherapy are unknown. We compared prone and supine treatment using real-time tracking data to model dose coverage.Material and methodsElectromagnetic tracking data were analyzed for 10 patients treated prone, and 15 treated supine, with IMRT for localized prostate cancer. Plans were generated using 0 mm, 3 mm, and 5mm PTV expansions. Manual beam-hold interventions were applied to reposition the patient when translations exceeded a predetermined threshold. A custom software application (SWIFTER) used intrafraction tracking data acquired during beam-on model delivered prostate dose, by applying rigid body transformations to the prostate structure contoured at simulation within the planned dose cloud. The delivered minimum prostate dose as a percentage of planned dose (Dmin%), and prostate volume covered by the prescription dose as a percentage of the planned volume (VRx%) were compared for prone and supine treatment.ResultsDmin% was reduced for prone treatment for 0 (p=0.02) and 3 mm (p=0.03) PTV margins. VRx% was reduced for prone treatment only for 0mm margins (p=0.002). No significant differences were found using 5 mm margins.ConclusionsIntrafraction motion has a greater impact on target coverage for prone compared to supine prostate radiotherapy. PTV margins of 3 mm or less correlate with a significant decrease in delivered dose for prone treatment.
| S-EPMC3423556 | biostudies-literature