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Clinics in Chest Medicine Dec 2014Multiple animal and human studies have shown that prone positioning improves oxygenation and reduces ventilator-induced lung injury (VILI) in the setting of acute lung... (Review)
Review
Multiple animal and human studies have shown that prone positioning improves oxygenation and reduces ventilator-induced lung injury (VILI) in the setting of acute lung injury or acute respiratory distress syndrome (ARDS). In this article, the physiologic changes explaining the improvement in oxygenation are reviewed, how prone positioning reduces VILI is described, randomized controlled trials of prone ventilation in patients with ARDS are evaluated, the complications associated with prone ventilation are summarized, suggestions are made as to how these might be reduced or avoided, and when prone ventilation should start and stop and for what duration it should be used are discussed.
Topics: Critical Care; Humans; Prone Position; Respiratory Distress Syndrome
PubMed: 25453422
DOI: 10.1016/j.ccm.2014.08.011 -
Chest Mar 2023
Topics: Humans; Lung; Respiratory Distress Syndrome; Prone Position; Supine Position
PubMed: 36894254
DOI: 10.1016/j.chest.2022.12.002 -
Annals of the American Thoracic Society Jan 2020
Meta-Analysis Review
Topics: Humans; Patient Positioning; Prone Position; Respiration, Artificial; Respiratory Distress Syndrome; Severity of Illness Index
PubMed: 31532692
DOI: 10.1513/AnnalsATS.201906-456IP -
Respiratory Care Aug 2017The prone posture is known to have numerous effects on gas exchange, both under normal conditions and in patients with ARDS. Clinical studies have consistently... (Review)
Review
The prone posture is known to have numerous effects on gas exchange, both under normal conditions and in patients with ARDS. Clinical studies have consistently demonstrated improvements in oxygenation, and a multi-center randomized trial found that, when implemented within 48 h of moderate-to-severe ARDS, placing subjects in the prone posture decreased mortality. Improvements in gas exchange occur via several mechanisms: alterations in the distribution of alveolar ventilation, redistribution of blood flow, improved matching of local ventilation and perfusion, and reduction in regions of low ventilation/perfusion ratios. Ventilation heterogeneity is reduced in the prone posture due to more uniform alveolar size secondary to a more uniform vertical pleural pressure gradient. The prone posture results in more uniform pulmonary blood flow when compared with the supine posture, due to an anatomical bias for greater blood flow to dorsal lung regions. Because both ventilation and perfusion heterogeneity decrease in the prone posture, gas exchange improves. Other benefits include a more uniform distribution of alveolar stress, relief of left-lower-lobe lung compression by the heart, enhanced secretion clearance, and favorable right-ventricular and systemic hemodynamics.
Topics: Adult; Female; Hemodynamics; Humans; Lung; Male; Middle Aged; Patient Positioning; Prone Position; Pulmonary Gas Exchange; Respiratory Distress Syndrome; Respiratory Mechanics
PubMed: 28559471
DOI: 10.4187/respcare.05512 -
Critical Care Nursing Quarterly 2019Adult respiratory distress syndrome (ARDS) is a clinical entity characterized by hypoxemic respiratory failure in the setting of noncardiogenic pulmonary edema. It is...
Adult respiratory distress syndrome (ARDS) is a clinical entity characterized by hypoxemic respiratory failure in the setting of noncardiogenic pulmonary edema. It is associated with significant morbidity and mortality. Prone positioning is a beneficial strategy in patients with severe ARDS because it improves alveolar recruitment, ventilation/perfusion (V/Q) ratio, and decreases lung strain. The outcome is improved oxygenation, decreased severity of lung injury, and, subsequently, mortality benefit. In this article, we discuss the physiology of prone positioning on chest mechanics and V/Q ratio, the placement and maintenance of patients in the prone position with use of a prone bed and the current literature regarding benefits of prone positioning in patients with ARDS.
Topics: Humans; Hypoxia; Prone Position; Pulmonary Alveoli; Pulmonary Edema; Respiration, Artificial; Respiratory Distress Syndrome
PubMed: 31449147
DOI: 10.1097/CNQ.0000000000000277 -
Medicine, Science, and the Law Jul 2022
Topics: Humans; Patient Positioning; Prone Position
PubMed: 34730057
DOI: 10.1177/00258024211051436 -
Clinical Medicine (London, England) Jul 2020Medical teams continue to treat many patients with COVID-19 infection. This disease can result in profound hypoxaemia that may necessitate intubation and invasive... (Review)
Review
Medical teams continue to treat many patients with COVID-19 infection. This disease can result in profound hypoxaemia that may necessitate intubation and invasive mechanical ventilation in those who are critically ill. This intervention carries risk to both patients and healthcare workers and utilises significant hospital resource for prolonged periods. Simple, safe interventions that can be used before critical deterioration are highly desirable. The prone position in conscious non-ventilated patients with COVID-19 infection may improve oxygenation in the short term and defer or prevent the need for intubation in some. However, clinicians must be aware that there is a small evidence base for this intervention currently. This review sets out evidence regarding the use of this technique to aid the decision making of frontline staff.
Topics: COVID-19; Consciousness; Coronavirus Infections; Humans; Oxygen Inhalation Therapy; Pandemics; Patient Positioning; Pneumonia, Viral; Prone Position; Respiration, Artificial
PubMed: 32503800
DOI: 10.7861/clinmed.2020-0179 -
Acta Paediatrica (Oslo, Norway : 1992) Aug 2020The world is facing an explosive COVID-19 pandemic. Some cases rapidly develop deteriorating lung function, which causes deep hypoxaemia and requires urgent treatment.... (Review)
Review
The world is facing an explosive COVID-19 pandemic. Some cases rapidly develop deteriorating lung function, which causes deep hypoxaemia and requires urgent treatment. Many centres have started treating patients in the prone position, and oxygenation has improved considerably in some cases. Questions have been raised regarding the mechanisms behind this. The mini review provides some insights into the role of supine and prone body positions and summarises the latest understanding of the responsible mechanisms. The scope for discussion is outside the neonatal period and entirely based on experimental and clinical experiences related to adults. The human respiratory system is a complex interplay of many different variables. Therefore, this mini review has prioritised previous and ongoing research to find explanations based on three scientific areas: gravity, lung structure and fractal geometry and vascular regulation. It concludes that gravity is one of the variables responsible for ventilation/perfusion matching but in concert with lung structure and fractal geometry, ventilation and regulation of lung vascular tone. Since ventilation distribution does not change between supine and prone positions, the higher expression of nitric oxide in dorsal lung vessels than in ventral vessels is likely to be the most important mechanism behind enhanced oxygenation in the prone position.
Topics: COVID-19; Coronavirus Infections; Humans; Hypoxia; Pandemics; Pneumonia, Viral; Prone Position
PubMed: 32484966
DOI: 10.1111/apa.15382 -
American Journal of Respiratory and... Jun 2021
Topics: Humans; Patient Positioning; Prone Position
PubMed: 33556302
DOI: 10.1164/rccm.202101-0156ED -
Current Opinion in Critical Care Jun 2016Prone positioning is recommended as a rescue therapy to improve arterial oxygenation in patients with severe acute respiratory distress syndrome (ARDS). In this review,... (Review)
Review
PURPOSE OF REVIEW
Prone positioning is recommended as a rescue therapy to improve arterial oxygenation in patients with severe acute respiratory distress syndrome (ARDS). In this review, we summarize the macro and the microcirculatory effects of prone positioning and emphasize which hemodynamic variables can be monitored when this therapy is applied.
RECENT FINDINGS
Early and prolonged prone positioning sessions significantly decrease the mortality of patients with severe ARDS. Prone positioning increases cardiac preload and decreases right ventricular afterload in patients with ARDS under protective ventilation and maximal lung recruitment. This results in an increase in cardiac output only in patients with preload reserve, emphasizing the important role of preload in the hemodynamic effects of prone positioning. Prone positioning might also exert some effects on regional and/or local blood flows, which mainly result from the increase in intra-abdominal pressure. Because prone positioning does not produce a significant increase in intra-abdominal pressure, it does not exert deleterious effects on the microcirculation of intra-abdominal organs.
SUMMARY
Prone positioning generally exerts beneficial macrocirculatory effects, which can result in increased cardiac output in patients with preload reserve without negatively altering regional circulations.
Topics: Cardiac Output; Hemodynamics; Humans; Microcirculation; Prone Position; Respiratory Distress Syndrome
PubMed: 27101363
DOI: 10.1097/MCC.0000000000000308