scholarly journals Prone Positioning May Increase Lung Overdistension in COVID-19-Induced ARDS

2021 ◽  
Author(s):  
Michal Otáhal ◽  
Mikuláš Mlček ◽  
João Batista Borges ◽  
Glasiele Cristina Alcala ◽  
Dominik Hladík ◽  
...  
Keyword(s):  
Prone Position ◽  
Respiratory System ◽  
Supine Position ◽  
Body Position ◽  
Prone Positioning ◽  
Respiratory System Compliance ◽  
Lung Collapse ◽  
Impedance Tomography ◽  
Regional Lung ◽  
Lung Overdistension

Abstract Background: Real-time effects of changing body position and positive end-expiratory pressure (PEEP) on regional lung overdistension and collapse in individual patients remain largely unknown and not timely monitored. The aim of this study was to individualize PEEP in supine and prone body positions seeking to reduce lung collapse and overdistension in mechanically ventilated patients with coronavirus disease (COVID-19)-induced acute respiratory distress syndrome (ARDS). We hypothesized that prone positioning with bedside titrated PEEP would provide attenuation of both overdistension and collapse.Methods: In this prospective observational study, patients with COVID-19-induced ARDS under mechanical ventilation were included. We used electrical impedance tomography (EIT) with decremental PEEP titration algorithm (PEEPEIT-titration), which provides information on regional lung overdistension and collapse, along with global respiratory system compliance, to individualize PEEP and body position. PEEPEIT-titration in supine position straightaway followed by PEEPEIT-titration in prone position were performed. Immediately before each PEEPEIT-titration, the same lung recruitment maneuver was performed: 2 min of PEEP 24 cmH2O and driving pressure of 15 cmH2O.Results: Forty-two PEEPEIT-titration were performed in ten patients (21 pairs supine and prone positions). We have found larger % of overdistension along the PEEP titration in prone than supine position (P = 0.042). A larger % of collapse along the PEEP titration was found in supine than prone position (P = 0.037). A smaller respiratory system compliance was found in prone than supine position (P < 0.0005).Conclusions: In patients with COVID-19-induced ARDS, prone body position, when compared with supine body position, decreased lung collapse at low PEEP levels, but increased lung overdistension at PEEP levels greater than 10 cm H2O.Trial registration number: NCT04460859

scholarly journals High-Flow Nasal Cannula and Prone Positioning in Awake Patients with COVID-19 Related Respiratory Failure: An Observational Study.

2021 ◽  
Author(s):  
Fekri Abroug ◽  
Zeineb Hammouda ◽  
Manel Lahmar ◽  
Wiem Nouira ◽  
Syrine Maatouk ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Observational Study ◽  
Prone Position ◽  
Supine Position ◽  
Early Response ◽  
High Flow ◽  
Nasal Cannula ◽  
Youden Index ◽  
Prone Positioning ◽  
High Flow Nasal Cannula

Abstract Background: We report an observational study on the use of High-flow nasal cannula (HFNC) and awake prone position in patients with Covid-19 related severe ARF.Methods: chart analysis of consecutive patients with confirmed Covid-19 and severe ARF (PaO2/FiO2 ratio <150) who received HFNC. Patients were systematically encouraged to lie in the prone position if tolerated. We calculated initial ROX index (the ratio of SpO2/FIO2 to respiratory rate) while in supine position and at the end of the first HFNC session whether in prone or supine position, and their difference (delta ROX). The success/failure of HFNC (need for intubation) was recorded. Predictors of HFNC failure were identified using ROC curve and logistic regression.Results: HFNC was administered to 213 out of 360 patients with COVID-19 related severe ARF (71% male, median age:59 years (IQR:50-68), median PaO2/FIO2: 104(73-143). At the start of HFNC, median ROX index was 4(3.4-5). Among included patients, 178 (83.5%) could tolerate prone position and had a median of 4.4(2-6) prone sessions during a median of 10(4-16) hours/day each, for a median of 4(2-7) days. Overall, HFNC failure occurred in 61 patients (28.1%) with similar proportions in patients who had HFNC in prone position and in patients who did not tolerate prone position (29% and 26%, respectively; relative risk:1.14. 95%CI:0.62-2.1). In the prediction of HFNC outcome, AUC was highest for delta ROX (AUC=0.83); AUC for baseline ROX (0.71), PaO2/FiO2 (0.73), and SpO2 (0.67), were significantly lower. The delta ROX cut-off ≤1.8 had the best Youden index indicating the best combination of sensitivity (0.89) and specificity (0.61) with a PLR (2.33) and a NLR (0.17) to predict HFNC failure. Logistic regression disclosed the following predictors of HFNC failure: delta ROX: RR=0.44, 95%CI=0.32-0.62; p-0.0001); baseline ROX index: RR=0.58, 95% CI:0.39-0.85, p=0.005); SOFA score (RR=1.6 for each point; 95%CI: 1.1-2.2, p=0.007); and PaO2/FiO2 at admission: RR=0.96, 95%CI=0.94-0.99). Prone position was not related to HFNC success.CONCLUSION: Awake HFNC in prone position is feasible in most patients with severe hypoxemic COVID-19. Indicators of ARF severity and the early response to HFNC, rather than prone position are independently associated with HFNC outcome.

Additive Effect of Nitric Oxide Inhalation on the Oxygenation Benefit of the Prone Position in the Adult Respiratory Distress Syndrome 

1998 ◽  
Vol 89 (6) ◽  
pp. 1401-1406 ◽  
Author(s):  
Peter Germann ◽  
Gerald Poschl ◽  
Christian Leitner ◽  
Georg Urak ◽  
Roman Ullrich ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Adult Respiratory Distress Syndrome ◽  
Prone Position ◽  
Supine Position ◽  
Distress Syndrome ◽  
Lung Injury Score ◽  
Prone Positioning ◽  
Nitric Oxide Inhalation

Background The response to inhaled nitric oxide and prone positioning was investigated in 47 patients with adult respiratory distress syndrome to test the hypothesis that inhalation of nitric oxide when in the prone position would result in additive improvement in oxygenation. Methods The authors prospectively studied patients of both genders who were 15 to 75 yr old and had adult respiratory distress syndrome confirmed by computed tomography (lung injury score, 3.1+/-1). Results Compared with baseline values in the supine position (T1), inhalation of 10 ppm nitric oxide for 1 h (T2) decreased the mean pulmonary artery pressure from 33+/-9 mmHg to 28+/-6 mmHg (P &lt; 0.05; T2 vs. T1) and increased the ratio of the partial pressure of oxygen in arterial blood (PaO2) to inspired oxygen concentration (FiO2) from 115 (median first quartile [Q1] 97, median third quartile [Q3] 137) to 148 (Q1 132, Q3 196) (P &lt; 0.05; T2 vs. T1). Cessation of nitric oxide brought the values back to baseline (T3). Two hours of prone positioning (T4) significantly increased the PaO2:FiO2 ratio (T4 vs. T3). However, after an additional hour of nitric oxide inhalation in the prone position (T5), a significant decrease of the venous admixture (from 33+/-6% to 25+/-6%; P &lt; 0.05) and an increase of the PaO2:FiO2 ratio (from 165 [Q1 129, Q3 216] to 199 [Q1 178, Q3 316] [P &lt; 0.05; T5 vs. T4]) were observed. Conclusions In patients with isolated severe adult respiratory distress syndrome, inhalation of nitric oxide in the prone position significantly improved oxygenation compared with nitric oxide inhalation in the supine position or in the prone position without nitric oxide. The combination of the prone position with nitric oxide inhalation in the treatment of severe adult respiratory distress syndrome should be considered.

scholarly journals Effects of Desflurane Versus Propofol Anesthesia on Regional Cerebral Oxygenation during Spinal Surgery in the Prone Position

2021 ◽  
pp. 1-6
Author(s):  
Stachtari Chrysoula ◽  
Koraki Eleni ◽  
Stachtari Chrysoula ◽  
Bagntasarian Stella ◽  
Gkiouliava Anna ◽  
...  
Keyword(s):  
Prone Position ◽  
Supine Position ◽  
Spinal Surgery ◽  
Cerebral Oxygenation ◽  
Demographic Data ◽  
Prone Positioning ◽  
Anaesthetic Agents ◽  
Oxygen Administration ◽  
Hemodynamic Variables ◽  
Significant Difference

Context: Postural change during anaesthesia has a complex effect on systemic and cerebral circulations. Aim: The goal of the study was to evaluate the effects of desflurane and propofol on cerebral oxygenation during spinal surgery in the prone position. Settings and Design: A prospective randomized double-blinded trial. Methods and Materials: Fifty-two patients scheduled for spinal surgery were randomly allocated to propofol (n=25) and desflurane (n=27) groups. Anaesthetic agents were maintained to obtain a bispectral index of 50-55. SAP, DAP, HR, SPO2, ETCO2 and right and left rSO2 were assessed at seven-time points: supine position without oxygen administration (T1), supine position with oxygen administration (T2-baseline), intubation in the supine position (T3), just after prone positioning (T4), 10 minutes after prone positioning (T5), at the end of surgery in the prone position (T6) and at the end of anaesthesia in the supine position (T7). PCO2, PO2 and Hb partial were also recorded at T3 and T7. Results: Demographic data, pre-oxygenation hemodynamic variables and rSO2 were comparable between the groups. There was no significant difference between groups in SAP, DAP, HR, SPO2, and ETCO2 (p=0.095, p=0.061, p=0.357, p=0.088, p=0.328 respectively). PCO2, PO2 and Hb were not significant different between groups (p=0.542, p=0.394, p=0.768 respectively). rSO2 values were not significantly different between groups. In the propofol group, right rSO2 was significantly higher at T3 (p=0.017) and significantly lower at T5 (p=0,019) and at T6 (p=0,028) compared to baseline. Left rSO2 decreased significantly from baseline at T5 (p=0.026) in the propofol group. Left and right rSO2 in the desflurane group decreased significantly from baseline at T5 (p=0.0004 and p=0.0115). Conclusion: In the prone position, desflurane and propofol were associated with a significant decrease in rSO2 without differences between these anaesthetics.

scholarly journals Electrical Impedance Tomography for Cardio-Pulmonary Monitoring

2019 ◽  
Vol 8 (8) ◽  
pp. 1176 ◽  
Author(s):  
Christian Putensen ◽  
Benjamin Hentze ◽  
Stefan Muenster ◽  
Thomas Muders
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Lung Perfusion ◽  
Clinical Aspects ◽  
Regional Ventilation ◽  
Impedance Tomography ◽  
Regional Lung ◽  
Lung Overdistension ◽  
Local Ventilation ◽  
Ventilation And Perfusion

Electrical impedance tomography (EIT) is a bedside monitoring tool that noninvasively visualizes local ventilation and arguably lung perfusion distribution. This article reviews and discusses both methodological and clinical aspects of thoracic EIT. Initially, investigators addressed the validation of EIT to measure regional ventilation. Current studies focus mainly on its clinical applications to quantify lung collapse, tidal recruitment, and lung overdistension to titrate positive end-expiratory pressure (PEEP) and tidal volume. In addition, EIT may help to detect pneumothorax. Recent studies evaluated EIT as a tool to measure regional lung perfusion. Indicator-free EIT measurements might be sufficient to continuously measure cardiac stroke volume. The use of a contrast agent such as saline might be required to assess regional lung perfusion. As a result, EIT-based monitoring of regional ventilation and lung perfusion may visualize local ventilation and perfusion matching, which can be helpful in the treatment of patients with acute respiratory distress syndrome (ARDS).

Regional lung viscoelastic properties in supine and prone position in a porcine model of acute respiratory distress syndrome

2021 ◽  
Author(s):  
Claude Guerin ◽  
Sam Bayat ◽  
Norbert Noury ◽  
Martin Cour ◽  
Laurent Argaud ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Chest Wall ◽  
Prone Position ◽  
Viscoelastic Properties ◽  
Airway Pressure ◽  
Distress Syndrome ◽  
Impedance Tomography ◽  
Regional Lung

Regional viscoelastic properties of thoracic tissues in acute respiratory distress syndrome (ARDS) and their change with position and positive end-expiratory pressure (PEEP) are unknown. In an experimental porcine ARDS, dorsal and ventral lung (R2,L and E2,L) and chest wall (R2,cw and E2,cw) viscoelastic resistive(R) and elastic(E) parameters were measured at 20, 15, 10 and 5 cmH2O PEEP in supine and prone position. E2 and R2 were obtained by fitting the decay of pressure after end-inspiratory occlusion to the equation: Pviscmax(t)=R2 e(-t/τ2), where t is length of occlusion and τ2 time constant. E2 was = R2/τ2. R2,cw and E2,cw were measured from esophageal, dorsal and ventral pleural pressures. Global R2,L and E2,L were obtained from the global trans-pulmonary pressure (airway pressure-esophageal pressure), and regional R2,L and E2,L from the dorsal and ventral airway pressure-pleural pressure difference. Lung ventilation was measured by electrical impedance tomography (EIT). Global R2,cw and E2,cw did not change with PEEP or position. Global R2,L (median(Q1-Q3)) was 37.1(11.0-65.1), 5.1(4.3-5.5), 12.1(8.4-19.5), and 41.0 (26.6-53.5) cmH2O/L/s in supine, and 15.3 (9.1-41.9), 7.9 (5.7-11.0), 8.0 (5.1-12.1) and 12.9 (6.4-19.4) cmH2O/L in prone from 20 to 5 cmH2O PEEP (P=0.06 for PEEP and P=0.06 for position). Dorsal R2,L significantly and positively correlated with amount of collapse measured with EIT. Global and regional lung and chest wall viscoelastic parameters can be described by a simple rheological model. Regional E2 and R2 were uninfluenced by PEEP and position except for PEEP on dorsal E2,L and position on dorsal E2,cw.

Axillary lymph node coverage of tangent radiotherapy: Comparison of supine versus prone positioning.

2012 ◽  
Vol 30 (27_suppl) ◽  
pp. 200-200 ◽  
Author(s):  
Gregory M. Thompson ◽  
Ruth F. Lavigne ◽  
Mark Dimascio ◽  
Carlos Bohorquez ◽  
Michael A. S. Lamba
Keyword(s):  
Lymph Node ◽  
Prone Position ◽  
Supine Position ◽  
Axillary Lymph Node ◽  
Local Therapy ◽  
Axillary Lymph ◽  
Prone Positioning ◽  
Breast Radiotherapy ◽  
Whole Breast Radiotherapy ◽  
Tangent Fields

200 Background: Recent randomized evidence has demonstrated low rates of axillary nodal failure in patients with one to two positive lymph nodes who receive local therapy with sentinel lymph node biopsy and simple tangential radiotherapy alone. Decreasing utilization of complete axillary nodal dissections has potential implications for radiotherapy treatment delivery design. We sought to compare the inadvertent coverage of the axillary lymph nodal regions between supine versus prone position for whole breast radiotherapy using simple tangent fields. Methods: Twenty patients with breast cancer who had previously received whole breast radiotherapy with simple tangent fields were randomly selected. Patients were selected such that 10 patients had received treatment in the supine position and 10 patients in the prone position. Axillary lymph node levels I-III were contoured by a single physician according to the RTOG breast contouring atlas. The previously generated radiotherapy plans, each to deliver a prescribed dose between 42.56 and 50Gy, were dosimetrically compared to assess differences in coverage of the nodal volumes. Results: In both positions, dose to each of the axillary nodal regions was low. For level I, the volume receiving 95% of the prescribed dose (V95) was 34.7% for supine positioning and 1.6% for prone positioning. All other analyzed volumes, specifically V25 (71.5% vs 32.6%), V50 (63.3% vs 28.2%), and V75 (57.6% vs 24.1%), were 50% greater for supine compared to prone positioning. Level II coverage was less with V95 of 6% and 0.1% respectively. Similarly V25 (32.8% vs 5.7%), V50 (25.7% vs 3.8%), and V75 (20.3% vs 2.1%) were less compared to level one and greater in the supine position. Level III coverage was less than 10% for both positions at all measured volumes of V95, V75, V50, and V25. Conclusions: Delivery of radiotherapy using simple tangents inadequately covers all axillary nodal levels. Coverage is greater in the supine position with very little inadvertent coverage in the prone position. The risk of nodal recurrence should be carefully considered when deciding to use a simple tangential field design. Additional factors such as dose to the lung and heart should also be considered for positioning.

Pleural liquid pressure measured with rib capsules in anesthetized ponies

1988 ◽  
Vol 64 (1) ◽  
pp. 102-107 ◽  
Author(s):  
L. E. Olson ◽  
S. J. Lai-Fook
Keyword(s):  
Prone Position ◽  
Supine Position ◽  
Body Position ◽  
Transpulmonary Pressure ◽  
Vertical Gradient ◽  
Liquid Pressure ◽  
Minimal Distortion ◽  
Poor Ventilation ◽  
Spontaneously Breathing ◽  
Pleural Liquid Pressure

Pleural liquid pressure was measured at end expiration in 11 spontaneously breathing anesthetized ponies in the prone and supine positions. A liquid-filled capsule was implanted into a rib to measure pleural liquid pressure with minimal distortion of the pleural space (Wiener-Kronish et al., J. Appl. Physiol. 59: 597-602, 1985). Capsule position relative to lung height was measured from thoracic radiographs taken in each position. In each body position, pleural liquid pressure was most negative in the superior lung regions and least negative in the inferior lung regions. In the supine position, the magnitude of the vertical gradient in pleural liquid pressure was 0.67 cmH2O/cm ht and was not significantly different from 1 cmH2O/cm ht. In the inferior lung regions (less than 50% lung ht), pleural liquid pressure averaged -1.3 cmH2O, indicating a low transpulmonary pressure over the region of the chest where most of the lung mass is located. When animals were in the prone position, the magnitude of the vertical gradient in pleural liquid pressure was 0.14 cmH2O/cm ht and was not statistically different from 0 cmH2O/cm ht. In each body position, mean transpulmonary pressure, measured postmortem, was similar to the estimated magnitude of pleural liquid pressure at 50% lung ht. This suggests that pleural liquid pressure is closely related to pleural surface pressure. These results are consistent with the poor ventilation distribution and reduced lung volumes measured in anesthetized horses in the supine position compared with values measured in horses in the prone position.

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