Table 2.

Mechanisms of Action of Magnesium in Pulmonary Complications of COVID-19.

Pulmonary/Respiratory Complication of COVID-19	Possible Link with Mg
Respiratory system is the main organ system involved in COVID-19 [130]	Intravenous Mg sulfate has a clinical impact on acute severe asthma [129]
	Mg sulfate can dilate constricted pulmonary arteries and reduce pulmonary artery resistance as well as induce bronchodilation by inhibition of airway smooth muscle contraction [126]
	Mg sulfate extended infusion has been suggested as an adjunctive treatment for critically ill patients with COVID-19 [131]
V/Q mismatch in COVID-19 may be responsible for severe respiratory complications of COVID-19 [121,122,123]
Inhalation therapies for COVID-19 suggested to improve oxygenation and V/Q mismatch [124,125]	Nebulized Mg sulfate therapy has been proposed to reduce V/Q mismatch and improve oxygenation [126]
	Nebulized Mg sulfate improved oxygenation in patients with severe COVID-19 with hypoxia with V/Q mismatch but less so for critically and very severely ill patients with COVID-19 with some degree of intrapulmonary shunt [126] [manuscript in preparation]

Abbreviations: Mg, magnesium; V/Q, ventilation–perfusion.