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Journal of Applied Physiology... Jun 2020Patients with moderate to severe acute respiratory distress syndrome (ARDS) benefit from prone positioning. Although the accuracy of esophageal pressure (Pes) to...
Patients with moderate to severe acute respiratory distress syndrome (ARDS) benefit from prone positioning. Although the accuracy of esophageal pressure (Pes) to estimate regional pleural pressure (Ppl) has previously been assessed in the supine position, such data are not available in the prone position in ARDS. In six anesthetized, paralyzed, and mechanically ventilated female pigs, we measured Pes and Ppl into dorsal and ventral parts of the right pleural cavity. Airway pressure (Paw) and flow were measured at the airway opening. Severe ARDS [arterial partial pressure of oxygen ([Formula: see text])/fraction of inspired oxygen ([Formula: see text]) < 100 mmHg at positive end-expiratory pressure (PEEP) of 5 cmHO] was induced by surfactant depletion. In supine and prone positions assigned in a random order, PEEP was set to 20, 15, 10, and 5 cmHO and static end-expiratory chest wall pressures were measured from Pes (PEEPtot,es) and dorsal (PEEPtot,PplD) and ventral (PEEPtot,PplV) Ppl. The magnitude of the difference between PEEPtot,es and PEEPtot,PplD was similar in each position [-3.6 cmHO in supine vs. -3.8 cmHO in prone at PEEP 20 cmHO (PEEP 20)]. The difference between PEEPtot,es and PEEPtot,PplV became narrower in the prone position (-8.3 cmHO supine vs. -3.0 cmHO prone at PEEP 20). PEEPtot,PplV was overestimated by Pes in the prone position at higher pressures. The median (1st-3rd quartiles) dorsal-to-ventral Ppl gradient was 4.4 (2.4-6.8) cmHO in the supine position and -1.5 (-3.5 to +1.1) cmHO in the prone position ( < 0.0001) and marginally influenced by PEEP ( = 0.058). Prone position narrowed end-expiratory dorsal-to-ventral Ppl vertical gradient, likely because of a more even distribution of mechanical forces over the chest wall. In a porcine model of acute respiratory distress syndrome, we found that static end-expiratory esophageal pressure did not change significantly in prone position compared with supine position at any positive end-expiratory pressure (PEEP) tested between 5 and 20 cmHO. Prone position was associated with an increased ventral pleural pressure and reduced end-expiratory dorsal-to-ventral pleural pressure (Ppl) vertical gradient, likely due to a more even distribution of mechanical forces over the chest wall.
Topics: Animals; Female; Humans; Patient Positioning; Positive-Pressure Respiration; Pressure; Prone Position; Respiratory Distress Syndrome; Swine
PubMed: 32437245
DOI: 10.1152/japplphysiol.00251.2020 -
Experimental Physiology Jul 2022What is the central question of this study? How does the interaction between posture and gravity affect the stresses on the lung, particularly in highly inflated...
NEW FINDINGS
What is the central question of this study? How does the interaction between posture and gravity affect the stresses on the lung, particularly in highly inflated gravitationally non-dependent regions, which are potentially vulnerable to increased mechanical stress and injury? What is the main finding and its importance? Changes in stress attributable to gravity are not well characterized between postures. Using a new metric of gravitational stress, we show that regions of the lung near maximal inflation have the greatest gravitational stresses while supine, but not while prone. In simulations of increased lung weight consistent with severe pulmonary oedema, the prone lung has lower gravitational stress in vulnerable, non-dependent regions, potentially protecting them from overinflation and injury.
ABSTRACT
Prone posture changes the gravitational vector, and potentially the stress induced by tissue deformation, because a larger lung volume is gravitationally dependent when supine, but non-dependent when prone. To evaluate this, 10 normal subjects (six male and four female; age, means ± SD = 27 ± 6 years; height, 171 ± 9 cm; weight, 69 ± 13 kg; forced expiratory volume in the first second/forced expiratory volume as a percentage of predicted, 93 ± 6%) were imaged at functional residual capacity, supine and prone, using magnetic resonance imaging, to quantify regional lung density. We defined regional gravitational stress as the cumulative weight, per unit area, of the column of lung tissue below each point. Gravitational stress was compared between regions of differing inflation to evaluate differences between highly stretched, and thus potentially vulnerable, regions and less stretched lung. Using reference density values for normal lungs at total lung capacity (0.10 ± 0.03 g/ml), regions were classified as highly inflated (density < 0.13 g/ml, i.e., close to total lung capacity), intermediate (0.13 ≤ density < 0.16 g/ml) or normally inflated (density ≥ 0.16 g/ml). Gravitational stress differed between inflation categories while supine (-1.6 ± 0.3 cmH O highly inflated; -1.4 ± 0.3 cmH O intermediate; -1.1 ± 0.1 cmH O normally inflated; P = 0.05) but not while prone (-1.4 ± 0.2 cmH O highly inflated; -1.3 ± 0.2 cmH O intermediate; -1.3 ± 0.1 cmH O normally inflated; P = 0.39), and increased more with height from dependent lung while supine (-0.24 ± 0.02 cmH O/cm supine; -0.18 ± 0.04 cmH O/cm prone; P = 0.05). In simulated severe pulmonary oedema, the gradient in gravitational stress increased in both postures (all P < 0.0001), was greater in the supine posture than when prone (-0.57 ± 0.21 cmH O/cm supine; -0.34 ± 0.16 cmH O/cm prone; P = 0.0004) and was similar to the gradient calculated from supine computed tomography images in a patient with acute respiratory distress syndrome (-0.51 cmH O/cm). The non-dependent lung has greater gravitational stress while supine and might be protected while prone, particularly in the presence of oedema.
Topics: Edema; Female; Humans; Lung; Male; Prone Position; Pulmonary Edema; Supine Position
PubMed: 33347661
DOI: 10.1113/EP089037 -
Contemporary Clinical Trials Oct 2021While benefits of prone position in mechanically-ventilated patients have been well-described, a randomized-control trial to determine the effects of prone positioning... (Randomized Controlled Trial)
Randomized Controlled Trial
While benefits of prone position in mechanically-ventilated patients have been well-described, a randomized-control trial to determine the effects of prone positioning in awake, spontaneously-breathing patients with an acute pneumonia has not been previously conducted. Prone Position and Respiratory Outcomes in Non-Intubated COVID-19 PatiEnts: the "PRONE" Study (PRONE) was conducted in non-intubated hospitalized patients with coronavirus disease 2019 (COVID-19) pneumonia as defined by respiratory rate ≥ 20/min or an oxyhemoglobin saturation (SpO) ≤ 93% without supplemental oxygen [1]. The PRONE trial was designed to investigate the effects of prone positioning on need for escalation in respiratory support, as defined by need for transition to a higher acuity level of care, increased fraction of inspired oxygen (FiO), or the initiation of invasive mechanical ventilation. Secondary objectives were to assess the duration of effect of prone positioning on respiratory parameters such as respiratory rate and SpO, as well as other outcomes such as time to discharge or transition in level of care.
Topics: COVID-19; Humans; Patient Positioning; Prone Position; Respiration, Artificial; SARS-CoV-2
PubMed: 34400361
DOI: 10.1016/j.cct.2021.106541 -
Acta Medica Okayama Oct 2022The purpose of this study was to investigate the psychological impact of various positionings in subjects with cerebral palsy (CP). The participants were 17 individuals...
The purpose of this study was to investigate the psychological impact of various positionings in subjects with cerebral palsy (CP). The participants were 17 individuals with severe motor and intellectual disability due to CP. They began in a sitting position in their wheelchair, and were placed consecutively in prone or supine positions, with no intervals between placements. Physiological observations were made in each position, and included salivary α-amylase activity, pulse, percutaneous oxygen saturation, respiratory rate, learance or not of airway secretions, and occurrence or not of adverse events. Salivary α-amylase activity values were higher in the prone position than in the baseline and supine positions (p<0.05). Clearance of airway secretions was significantly more prevalent in the prone position than in the baseline and supine positions (p <0.05). The participants' pulse was significantly lower in the supine and prone positions than in the baseline position (p<0.05). Greater prevalence of airway secretion clearance and significantly higher stress levels as indicated by saliva amylase were observed in the prone position than in the other two positions. Therefore, when such patients are placed in a prone position, close attention to airway management and the potential for psychological stress may be necessary.
Topics: Humans; Prone Position; Cerebral Palsy; Salivary alpha-Amylases; Patient Positioning; Stress, Psychological
PubMed: 36352800
DOI: 10.18926/AMO/64034 -
Intensive & Critical Care Nursing Oct 2022To examine the effectiveness of prone positioning on COVID-19 patients with acute respiratory distress syndrome with moderating factors in both traditional prone... (Meta-Analysis)
Meta-Analysis
Effectiveness of prone position in acute respiratory distress syndrome and moderating factors of obesity class and treatment durations for COVID-19 patients: A meta-analysis.
OBJECTIVES
To examine the effectiveness of prone positioning on COVID-19 patients with acute respiratory distress syndrome with moderating factors in both traditional prone positioning (invasive mechanical ventilation) and awake self-prone positioning patients (non-invasive ventilation).
RESEARCH METHODOLOGY
A comprehensive search was conducted in CINAHL, Cochrane library, Embase, Medline-OVID, NCBI SARS-CoV-2 Resources, ProQuest, Scopus, and Web of Science without language restrictions. All studies with prospective and experimental designs evaluating the effect of prone position patients with COVID-19 related to acute respiratory distress syndrome were included. Pooled standardised mean differences were calculated after prone position for primary (PaO/FiO) and secondary outcomes (SpO and PaO) RESULTS: A total of 15 articles were eligible and included in the final analysis. Prone position had a statistically significant effect in improving PaO/FiO with standardised mean difference of 1.10 (95%CI 0.60-1.59), SpO with standardised mean difference of 3.39 (95% CI 1.30-5.48), and PaO with standardised mean difference of 0.77 (95% CI 0.19-1.35). Patients with higher body mass index and longer duration/day are associated with larger standardised mean difference effect sizes for prone positioning.
CONCLUSIONS
Our findings demonstrate that prone position significantly improved oxygen saturation in COVID-19 patients with acute respiratory distress syndrome in both traditional prone positioning and awake self-prone positioning patients. Prone position should be recommended for patients with higher body mass index and longer durations to obtain the maximum effect.
Topics: COVID-19; Duration of Therapy; Humans; Obesity; Prone Position; Prospective Studies; Respiration, Artificial; Respiratory Distress Syndrome; SARS-CoV-2
PubMed: 35672215
DOI: 10.1016/j.iccn.2022.103257 -
Intensive Care Medicine Dec 2020Care for patients with acute respiratory distress syndrome (ARDS) has changed considerably over the 50 years since its original description. Indeed, standards of care... (Review)
Review
Care for patients with acute respiratory distress syndrome (ARDS) has changed considerably over the 50 years since its original description. Indeed, standards of care continue to evolve as does how this clinical entity is defined and how patients are grouped and treated in clinical practice. In this narrative review we discuss current standards - treatments that have a solid evidence base and are well established as targets for usual care - and also evolving standards - treatments that have promise and may become widely adopted in the future. We focus on three broad domains of ventilatory management, ventilation adjuncts, and pharmacotherapy. Current standards for ventilatory management include limitation of tidal volume and airway pressure and standard approaches to setting PEEP, while evolving standards might focus on limitation of driving pressure or mechanical power, individual titration of PEEP, and monitoring efforts during spontaneous breathing. Current standards in ventilation adjuncts include prone positioning in moderate-severe ARDS and veno-venous extracorporeal life support after prone positioning in patients with severe hypoxemia or who are difficult to ventilate. Pharmacotherapy current standards include corticosteroids for patients with ARDS due to COVID-19 and employing a conservative fluid strategy for patients not in shock; evolving standards may include steroids for ARDS not related to COVID-19, or specific biological agents being tested in appropriate sub-phenotypes of ARDS. While much progress has been made, certainly significant work remains to be done and we look forward to these future developments.
Topics: COVID-19; Fluid Therapy; Humans; Prone Position; Respiratory Distress Syndrome; Standard of Care
PubMed: 33156382
DOI: 10.1007/s00134-020-06299-6 -
Critical Care (London, England) Sep 2022Recent reports of patients with severe, late-stage COVID-19 ARDS with reduced respiratory system compliance described paradoxical decreases in plateau pressure and...
BACKGROUND
Recent 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.
METHODS
This 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/cmHO) or lower respiratory system compliance (< 40 ml/cmHO). 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.
RESULTS
Totally, 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, PaO/FiO 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/cmHO, p < 0.001). The improvement was higher the lower the baseline compliance.
CONCLUSIONS
Unlike 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.
Topics: COVID-19; Cohort Studies; Critical Illness; Humans; Prone Position; Prospective Studies; Respiratory Distress Syndrome; Respiratory Mechanics; Thoracic Wall
PubMed: 36100903
DOI: 10.1186/s13054-022-04141-7 -
Heart & Lung : the Journal of Critical... 2020Despite proven benefits to prone positioning in ARDS, a disconnect exists regarding the impressions of its utility among members of the healthcare team. While the...
Despite proven benefits to prone positioning in ARDS, a disconnect exists regarding the impressions of its utility among members of the healthcare team. While the majority of physicians view prone positioning as beneficial in ARDS, recent data suggest that the minority of ICU nurses have the same impression. The COVID pandemic has raised particularly challenges in terms of availability of personnel and supplies at least in some institutions. We discuss various barriers to implementation of prone positioning and suggest a number of strategies to optimize patient care. We use a multidisciplinary team approach to execute prone positioning in COVID ARDS.
Topics: Attitude of Health Personnel; Betacoronavirus; COVID-19; Coronavirus Infections; Humans; Pandemics; Patient Positioning; Pneumonia, Viral; Prone Position; Respiratory Distress Syndrome; SARS-CoV-2
PubMed: 32861885
DOI: 10.1016/j.hrtlng.2020.08.006 -
Respiratory Care Aug 2022Prone positioning (PP) has been used extensively for patients requiring invasive mechanical ventilation for hypoxemic respiratory failure during the COVID-19 pandemic....
Prone positioning (PP) has been used extensively for patients requiring invasive mechanical ventilation for hypoxemic respiratory failure during the COVID-19 pandemic. Evidence suggests that PP was beneficial during the pandemic, as it improves oxygenation and might improve chances of survival, especially in those with a continuum of positive oxygenation responses to the procedure. Additionally, the pandemic drove innovation regarding PP, as it brought attention to awake PP (APP) and the value of an interdisciplinary team approach to PP during a pandemic. APP appears to be safe and effective at improving oxygenation; APP may also reduce the need for intubation in patients requiring advanced respiratory support like high-flow nasal cannula or noninvasive ventilation. Teams specifically assembled for PP during a pandemic also appear useful and can provide needed assistance to bedside clinicians in the time of crisis. Complications associated with PP can be mitigated, and a multidisciplinary approach to reduce the incidence of complications is recommended.
Topics: COVID-19; Humans; Noninvasive Ventilation; Pandemics; Patient Positioning; Prone Position; Respiratory Insufficiency
PubMed: 35882445
DOI: 10.4187/respcare.10141 -
Critical Care (London, England) Aug 2021This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2021. Other selected articles can be found online at ... (Review)
Review
This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2021. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2021 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .
Topics: Extracorporeal Membrane Oxygenation; Humans; Intensive Care Units; Patient Positioning; Prone Position; Respiratory Distress Syndrome; Survival Analysis
PubMed: 34461971
DOI: 10.1186/s13054-021-03675-6