scholarly journals Using exhalation dynamics to evaluate PEEP levels in COVID-19 related ARDS

2021 ◽  
Author(s):  
Filip Depta
Keyword(s):  
Prone Position ◽  
Supine Position ◽  
Peep Level ◽  
Measured Parameter ◽  
Mechanically Ventilated ◽  
Lung Physiology ◽  
Pressure Controlled Ventilation ◽  
Patient Responses ◽  
A Prospective Study ◽  
Pressure Controlled

Abstract Background We hypothesized that measured expiratory time constant (TauE) could be a bedside parameter for evaluation of PEEP settings in mechanically ventilated COVID-19 patients during pressure-controlled ventilation (PCV) mode. TauE is an easily measured parameter to assess lung physiology, even in non-homogeneous lungs including COVID-19 ARDS. Methods A prospective study was conducted including consecutively admitted adults (n = 16) with COVID-19 related ARDS requiring mechanical ventilation. Ventilator settings for all patients included: PCV, RR 18/min, constant inspiratory pressure 14 cmH2O, I:E ratio 1:1.5 and FiO2 1.0. Escalating levels of PEEP (0 to 18 cmH2O) were applied and measured TauE and expiratory tidal volume (Vte) recorded. Next, a new parameter, TauE Index (TEI) was calculated (TEI = TauE * Vte) at each PEEP level in prone (n = 29) or supine (n = 24) positions. TEI maps were created to graphically show changes in individual physiology with PEEP. The PEEP setting with the highest TEI corresponded to the highest product of TauE and Vte and was considered the most suitable PEEP. Most suitable PEEP range was calculated as ± 10% from highest TEI. Results Two groups of patterns were observed in the TEI maps, recruitable (R) (75%) and non-recruitable (NR) (25%). In R group, the most suitable PEEP and PEEP range was 9±3 cmH2O and 6-12 cmH2O for prone position and 11±3 cmH2O and 7-13 cmH2O for supine position. In NR group, the most suitable PEEP and PEEP range was 7±3 cmH2O and 0-8 cmH2O for prone position and 4±2 cmH2O and 0-7 cmH2O for supine position, respectively. The R group showed significantly higher suitable PEEP (p<0.01) and PEEP ranges (p<0.01) than NR group. 45% of measurements resulted in most suitable PEEP being significantly different between the positions (p < 0.01). Conclusions Based on TEI mapping, responses to PEEP were easily measured. There was wide variation in patient responses to PEEP that indicate the need for personalized evaluation.

Can the Tomographic Aspect Characteristics of Patients Presenting with Acute Respiratory Distress Syndrome Predict Improvement in Oxygenation-related Response to the Prone Position?

2002 ◽  
Vol 97 (3) ◽  
pp. 599-607 ◽  
Author(s):  
Laurent Papazian ◽  
Marie-Héléne Paladini ◽  
Fabienne Bregeon ◽  
Xavier Thirion ◽  
Olivier Durieux ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Prone Position ◽  
Supine Position ◽  
Distress Syndrome ◽  
Arterial Oxygen ◽  
Computed Tomographic ◽  
Computed Tomographic Scan ◽  
A Prospective Study

Background In some patients with acute respiratory distress syndrome, the prone position is able to improve oxygenation, whereas in others it is not. It could be hypothesized that the more opacities that are present in dependent regions of the lung when the patient is in the supine position, the better the improvement in oxygenation is observed when the patients are turned prone. Therefore, we conducted a prospective study to identify computed tomographic scan aspects that could accurately predict who will respond to the prone position. Methods We included 46 patients with acute respiratory distress syndrome (31 responders and 15 nonresponders). Computed tomographic scan was performed in the 6-h period preceding prone position. Blood gas analyses were performed before and at the end of the first 6-h period of prone position. Results Arterial oxygen partial pressure/fraction of inspired oxygen increased from 117 +/- 42 (mean +/- SD) in the supine position to 200 +/- 76 mmHg in the prone position (P &lt; 0.001). There were 31 responders and 15 nonresponders. There was a vertebral predominance of the opacities (P &lt; 0.0001). However, there was no difference between responders and nonresponders. When only the amount of consolidated lung located under the heart was evaluated, there was more consolidated tissue under the heart relative to total lung area in nonresponders than in responders (P = 0.01). Conclusions There are no distinctive morphologic features in the pattern of lung disease measured by computed tomographic scanning performed with the patient in the supine position that can predict response to the prone position.

scholarly journals Dynamics of tidal volume and ventilation heterogeneity under pressure-controlled ventilation during bronchoconstriction: a simulation study

2010 ◽  
Vol 109 (4) ◽  
pp. 1211-1218 ◽  
Author(s):  
Chanikarn Wongviriyawong ◽  
Tilo Winkler ◽  
R. Scott Harris ◽  
Jose G. Venegas
Keyword(s):  
Tidal Volume ◽  
Dynamic Equilibrium ◽  
Mechanically Ventilated ◽  
Volume Stability ◽  
Asthmatic Patients ◽  
Controlled Ventilation ◽  
Pressure Controlled Ventilation ◽  
Ventilation Heterogeneity ◽  
The Difference ◽  
Pressure Controlled

The difference in effectiveness between volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) on mechanically ventilated patients during bronchoconstriction is not totally clear. PCV is thought to deliver a more uniform distribution of ventilation than VCV, but the delivered tidal volume could be unstable and affected by changes in the degree of constriction. To explore the magnitude of these effects, we ran numerical simulations with both modes of ventilation in a network model of the lung in which we incorporated not only the pressure and flow dynamics along the airways but also the effect of cycling pressures and tissue tethering forces during breathing on the dynamic equilibrium of the airway smooth muscle (ASM) (Venegas et al., Nature 434: 777–782). These simulations provided an illustration of changes in airway radii, the total delivered tidal volume stability, and distribution of ventilation following a transition from VCV to PCV and during progressively increasing ASM activation level. These simulations yielded three major results. First, the ventilation heterogeneity and patchiness in ventilation during steady-state VCV were substantially reduced after the transition to PCV. Second, airway radius, tidal volume, and the distribution of ventilation under severe bronchoconstriction were highly sensitive to the setting of inspiratory pressure selected for PCV and to the degree of activation of the ASM. Third, the dynamic equilibrium of active ASM exposed to cycling forces is the major contributor to these effects. These insights may provide a theoretical framework to guide the selection of ventilation mode, the adjustment of ventilator settings, and the interpretation of clinical observations in mechanically ventilated asthmatic patients.

scholarly journals A Review of the Tolerance and Adequacy of Enteral Nutrition Administered in the Prone Position in Critically Ill Patients Receiving Mechanical Ventilation

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 216-216
Author(s):  
Carolyn Ellis ◽  
Miranda Brown ◽  
Kristine Anne Del Rosario ◽  
Paige Heiden ◽  
Gabriella Salazar ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Enteral Nutrition ◽  
Critically Ill ◽  
Prone Position ◽  
Supine Position ◽  
Dropout Rate ◽  
Cochrane Library ◽  
Prone Positioning ◽  
Inclusion Criteria ◽  
Mechanically Ventilated

Abstract Objectives During the coronavirus 2019 (COVID-19) pandemic, more patients require enteral nutrition (EN) while mechanically ventilated in the prone position (PP). Prone positioning may improve oxygenation in patients receiving mechanical ventilation; however, it is unclear how it affects EN adequacy and tolerance. This review explored how EN delivered in the PP impacts EN tolerance (vomiting, diarrhea, abdominal distention, or aspiration pneumonia) and adequacy (meeting estimated energy and protein requirements) in critically ill adults receiving mechanical ventilation. Methods A literature search was conducted in PubMed, CINAHL, Academic Search Premier, and Cochrane Library for English-language studies exploring EN administered in the PP published between 2000–2020. Studies that met inclusion criteria enrolled adult patients in intensive care units with acute respiratory distress syndrome or other respiratory conditions requiring mechanical ventilation, were cohort studies with ≥5 patients per study group, and had a dropout rate &lt;20%. Studies were excluded if patients received only parenteral nutrition. Results Of 45 studies, 4 met inclusion criteria. Three were prospective cohorts and 1 was a before-after study. When comparing EN tolerance in the PP and supine positions, 1 study found no difference in diarrhea occurrence, 2 studies found no difference in the rate of vomiting, and 1 study found significantly higher rates of vomiting while in the PP. For feeding adequacy, 2 studies found no difference in the % of calories received when administered in prone or supine positions, while 1 study found patients in the PP received significantly less EN volume than patients in the supine position. One study concluded that prophylactic prokinetic agent use and head elevation while prone resulted in larger EN volumes delivered with reduced vomiting risk. Conclusions These results suggest the adequacy of EN delivered in the PP is comparable to the supine position and PP does not substantially increase vomiting or diarrhea risk. Prone positioning should not be considered an immediate contraindication to EN for adults receiving mechanical ventilation. These findings may apply to the nutritional management of critically ill mechanically ventilated adults with COVID-19. Funding Sources None

scholarly journals Nursing care and prevalence of adverse events in prone position: Characteristics of mechanically ventilated patients with severe SARS‐CoV‐2 pulmonary infection

2021 ◽  
Author(s):  
María Dolores Rodríguez‐Huerta ◽  
Ana Díez‐Fernández ◽  
María Jesús Rodríguez‐Alonso ◽  
María Robles‐González ◽  
María Martín‐Rodríguez ◽  
...  
Keyword(s):  
Adverse Events ◽  
Prone Position ◽  
Nursing Care ◽  
Pulmonary Infection ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Ventilated Patients
Sign in / Sign up

Export Citation Format

Share Document