In patients with acute respiratory distress syndrome (ARDS), is early application of prone positioning more effective than supine positioning at reducing mortality?
Early Prone Positioning in the Reduction of Mortality
PICOT QUESTION: In patients with acute respiratory distress syndrome (ARDS), is early application of prone positioning more effective than supine positioning at reducing mortality?
Over the last two years, prone positioning has been initiated in the ICUs due to the development of acute respiratory distress syndrome (ARDS) because of COVID-19. Prone positioning was unfamiliar to me until the beginning of the pandemic. As we all know, due to the complexity of the coronavirus, there were interventions that were initiated by clinicians that seem to have improved patient outcomes. After briefly researching the benefits of prone positioning in 2019, I realized this intervention has been shown to be beneficial since the 1970’s. Prone positioning consists of placing a patient face down. Prone positioning has been used for more than 40 years to improve oxygenation in patients who require invasive mechanical ventilation for ARDS. The first demonstration of a beneficial effect on patients’ oxygenation was shown in 1974 (Touchon et al.,2021). I chose this PICO question because the initiation of prone positioning is prevalent in ICUs and I thought it would be great to research if early initiation, in fact, does reduces mortality amongst ARD’s patients. As a future nurse practitioner, in a pandemic, determining the effectiveness of treatment plan for ARDS would help me formulate a successful plan of care.
I think it’s essential to understand the physiologic effects of prone positioning before initiation, which I found rather interesting while doing research on my PICOquestion. When an individual with ARDS is supine, the heart compresses the medial posterior lung parenchyma, and the diaphragm compresses the posterior-caudal lung parenchyma. The latter is caused by the abdominal contents displacing the diaphragm cranially, which can be exacerbated by a loss of diaphragmatic tone due to sedation and/or paralysis or increased abdominal pressure. Compression by either the heart and/or the diaphragm may exaggerate dependent lung collapse in the supine position, increasing hypoxemia and ventilator-associated lung injury. During prone ventilation, the heart becomes dependent, potentially decreasing medial posterior lung compression. In addition, the diaphragm is displaced caudally (especially in obese patients and when the abdomen is left unsupported), decreasing compression of the posterior-caudal lung parenchyma (Malhorta, 2021). These effects improve ventilation and oxygenation. Ventilation/perfusion match improves when the patient is moved into the prone position as the previously dependent lung continues to receive most of the blood flow as alveoli reopen, while the newly dependent lung continues to receive the minority of the blood flow as alveoli begin to collapse. In addition, increases in cardiac output have been observed and thought to be because of increased lung recruitment and reduction in hypoxic pulmonary vasoconstriction resulting in increases in right ventricular preload and decreased right ventricular afterload and a decrease in pulmonary vascular resistance (Malhorta, 2021).
It’s evident that the use of prone positioning has been widely adopted now since the pandemic. One common entity between my job and clinical, was that patients with ARDS were placed in prone positioning only if intubated and paralyzed. Initially, I assumed that prone positioning was to only be initiated on intubated patients. But it was noted in many articles that awake prone positioning can be initiated on patients with ARDS while on high flow nasal cannula as well. I’ve come to the realization that there were many studies done on prone positioning in ARDS patients that I was unaware of, therefore I decided to educate myself on this topic. Whether the development of ARDS is related to an infectious or non-infectious process, prone positioning has been proven to have a more successful outcome than with supine positioning. Overall, this paper will educate me on the effectiveness of prone positioning and help me better manage patients with ARDS in my career as a nurse practitioner.
References
Malhorta, A. (2021). Prone ventilation for adult patients with acute respiratory distress syndrome. UpToDate. Retrieved from https://www.uptodate.com/contents/prone-ventilation-for-adult-patients-with-acute-respiratory-distress-syndrome/print#!
Touchon, F., Trigui, Y., Prud’homme, E., Lefebvre, L., Giraud, A., Dols, A.-M., Martinez, S., Bernardi, M., Begne, C., Granier, P., Chanez, P., Forel, J.-M., Papazian, L., & Elharrar, X. (2021). Awake prone positioning for hypoxaemic respiratory failure: Past, COVID-19 and Perspectives. European Respiratory Review, 30(160), 210022. https://doi.org/10.1183/16000617.0022-2021
