ARDS relation with Prone position.

I agree that prone positioning improves oxygenation and reduces mortality in patients with acute respiratory distress syndrome. Hence, this article will discuss the effects of prone position regarding oxygenation and mortality in patients with ARDS.

First, to understand the positive effects of prone position in ARDS patients, ARDS pathophysiology must be understood. ARDS is a serious and progressive condition in which severe impairment of gas exchange and lungs functions occurs (Han, et al, 2015). ARDS can be characterized by two main points persistent hypoxemia and decreased lungs compliance(Gattinoni, et al, 2016). ARDS occurs because of direct insult such as pneumonia, aspiration or indirect insult such as sepsis and shock which will trigger a systemic inflammatory response syndrome. This insult will contribute to the injury of the alveolar epithelium cells and pulmonary vasculature which will lead to increase alveolar capillaries permeability causing alveolar and interstitial edema. Furthermore, damage of type II alveoli will decrease the surfactant which will result in decreased lungs compliance. Hence, hypoxemia occurs and cause respiratory failure (Drahnak, et al, 2015). From here, the prone position becomes a highly recommended for ARDS patients.

The effects of prone position in ARDS patients are very significant. Prone position is a well-known method to improve oxygenation. By placing the patients on prone position, the pleural pressure gradient will be reduced and move from non-dependent to dependent regions in part via gravitational effects and conformational shape-matching of the lung to the chest cavity. As a result, lung aeration and strain distribution are more homogeneous. Moreover, the compression of lungs will help in reopening of collapsed alveoli the and reflate it which will also help in increase oxygenation (Scholten, et al, 2017). Significantly, Dessap, et al have reported that prone position increased oxygenation in 70% to 80 % of ARDS patients(Dessap, et al, 2011).

Prone position is not only used to improve oxygenation. It is also used to improve and facilitate lymphatic drainage and helps in removal of secretions. Moreover, prone position protects the lungs by preventing ventilator induced lung injury VILI. By preventing VILI, the survival rate will increase and mortality rate will decrease in ARDS patients (Scholten, et al, 2017). One of the most known studies that have proven the effects of prone position on reducing mortality rate is Guérin, et al study. This study was published in 2013. The aim of the study was to evaluate the effects of the early application of prone position on the outcomes in patients with ARDS. The researchers assigned a total number of 466 patients with ARDS randomly in two groups. The first group consists of 237 patients using prone position. The second group acts as a control group in a supine position with 229 patients. In the 28^th day, they evaluate the two groups and found that the mortality rate was 16% in the prone position group and 32.8% in the supine position group. There was no significant difference between the two groups regarding the incidence of complications except for cardiac arrest which was higher in supine group (Guérin, et al, 2013).

In summary, Prone position effects had been proven by many studies. Treating ARDS is very challenging for all health care providers around the world. Hence, many studies have recommended that prone position should be used as a policy in treating ARDS for its well-known effects in improving oxygenation, facilitate secretions derange and protecting the lungs against VILI(Albert, et al, 2014), (Gattinoni, et al, 2016), (Guérin, et al, 2013).

References:

Albert, R. K., Keniston, A., Baboi, L., Ayzac, L., &Guérin, C. (2014). Prone position-induced improvement in gas exchange does not predict improved survival in the acute respiratory distress syndrome. American journal of respiratory and critical care medicine, 189(4), 494-496

Dessap, A. M., Proost, O., Boissier, F., Louis, B., Campo, F. R., &Brochard, L. (2011). Transesophageal echocardiography in prone position during severe acute respiratory distress syndrome. Intensive care medicine, 37(3), 430-434.

Drahnak, D. M., & Custer, N. (2015). Prone positioning of patients with acute respiratory distress syndrome. Critical care nurse, 35(6), 29-37.

Gattinoni, L., &Quintel, M. (2016). How ARDS should be treated. Critical Care, 20(1), 86

Gattinoni, L., Taccone, P., Carlesso, E., & Marini, J. J. (2013). Prone position in acute respiratory distress syndrome. Rationale, indications, and limits. American journal of respiratory and critical care medicine, 188(11), 1286-1293.

Guérin, C., Reignier, J., Richard, J. C., Beuret, P., Gacouin, A., Boulain, T., ... &Clavel, M. (2013). Prone positioning in severe acute respiratory distress syndrome. New England Journal of Medicine, 368(23), 2159-2168

Han, S., &Mallampalli, R. K. (2015). The acute respiratory distress syndrome: from mechanism to translation. The Journal of Immunology, 194(3), 855-860

Scholten, E. L., Beitler, J. R., Prisk, G. K., & Malhotra, A. (2017). Treatment of ARDS with prone positioning. Chest, 151(1), 215-224