The role of hypercapnia in acute respiratory failure

Abstract

The biological effects and physiological consequences of hypercapnia are increasingly understood. The literature on hypercapnia is confusing, and at times contradictory. On the one hand, it may have protective effects through attenuation of pulmonary inflammation and oxidative stress. On the other hand, it may also have deleterious effects through inhibition of alveolar wound repair, reabsorption of alveolar fluid, and alveolar cell proliferation. Besides, hypercapnia has meaningful effects on lung physiology such as airway resistance, lung oxygenation, diaphragm function, and pulmonary vascular tree. In acute respiratory distress syndrome, lung-protective ventilation strategies using low tidal volume and low airway pressure are strongly advocated as these have strong potential to improve outcome. These strategies may come at a price of hypercapnia and hypercapnic acidosis. One approach is to accept it (permissive hypercapnia); another approach is to treat it through extracorporeal means. At present, it remains uncertain what the best approach is. Electronic supplementary material The online version of this article (10.1186/s40635-019-0239-0) contains supplementary material, which is available to authorized users.

Comment on COVID‐19 in patients with myasthenia gravis: Author response

“…5,6 Hypercapnic acidosis may also impair diaphragmatic function even in people without MG via effects on the vagus nerve. 7,8 We agree with the authors that pulmonary function tests may be of utility in evaluating patients with MG and COVID-19. Practically speaking, however, many medical centers may have avoided performing spirometry testing on patients with COVID-19 because of the risk of aerosolization of viral particles and nosocomial transmission.…”

“…5 Hypovitaminosis D may cause neurological deficits involving both the peripheral and central nervous systems . 6,7 Hypovitaminosis D is highly prevalent in patients with type 2 diabetes mellitus. 6 The degree of hypovitaminosis D correlates well with the severity of diabetic neuropathy 6 involving both large 8 and small 5 fibers.…”

Pre-Treatment with Ten-Minute Carbon Dioxide Inhalation Prevents Lipopolysaccharide-Induced Lung Injury in Mice via Down-Regulation of Toll-Like Receptor 4 Expression

“…Further studies are needed to investigate the different mechanisms. TLR4 can sense pathogenic microorganisms by binding the bacterial product, LPS, to defend against invading pathogens [6]. However, TLR4 also can cause septic shock that involves overstimulation of the immune system [7].…”

“…Hypercapnia and hypercapnic acidosis (HCA) exerts multiple important effects in lung injury and acute respiratory failure, which may be beneficial or deleterious to multiple biological pathways [6,7]. Previous ARDS studies have demonstrated that permissive hypercapnia is associated with lower hospital mortality [8,9].…”

Isolated Lung Perfusion in the Management of Acute Respiratory Distress Syndrome

“…This is, to some degree, an accepted consequence, leading to a concept known as permissive hypercapnia. Beneficial effects of hypercapnia have been demonstrated, including reduction in pulmonary inflammation and oxidative stress [ 13 , 14 ]. However, recent evidence has emerged suggesting negative impacts of hypercapnia on lung tissue repair and alveolar fluid clearance [ 13 , 15 ].…”