Acid-Base Disturbances in Patients with Asthma: A Literature Review and Comments on Their Pathophysiology

Abstract

Asthma is a common illness throughout the world that affects the respiratory system function, i.e., a system whose operational adequacy determines the respiratory gases exchange. It is therefore expected that acute severe asthma will be associated with respiratory acid-base disorders. In addition, the resulting hypoxemia along with the circulatory compromise due to heart–lung interactions can reduce tissue oxygenation, with a particular impact on respiratory muscles that have increased energy needs due to the increased workload. Thus, anaerobic metabolism may ensue, leading to lactic acidosis. Additionally, chronic hypocapnia in asthma can cause a compensatory drop in plasma bicarbonate concentration, resulting in non-anion gap acidosis. Indeed, studies have shown that in acute severe asthma, metabolic acid-base disorders may occur, i.e., high anion gap or non-anion gap metabolic acidosis. This review briefly presents studies that have investigated acid-base disorders in asthma, with comments on their underlying pathophysiology.

Effects of Continuous Albuterol Inhalation on Serum Metabolome in Healthy Subjects: More Than Just Lactic Acid

“…The hyperlactatemia can occur regardless of the route of β2‐agonist delivery, 7 is dose‐related, 12 occurs more often in asthmatics than healthy controls, 3,5 and is reversible after discontinuation of β2‐agonists 13 . There are mixed data on the impact of this lactic acidosis on mortality 2,6 …”

“…13 There are mixed data on the impact of this lactic acidosis on mortality. 2,6 The mechanism of β2-agonist lactic acidosis remains controversial, and several mechanisms have been proposed. 3 However, it was previously proposed to be a type A lactic acidosis in healthy participants receiving β2-agonists, and there should be limited anaerobic metabolism.…”

“…5 The phenomenon of hyperlactatemia after receiving β2-agonists is well documented in case reports, trials of healthy volunteers, and symptomatic patients in both emergency departments and intensive care units. 3,[5][6][7] Several mechanisms have been proposed; however, the exact mechanism remains controversial. 8 It was originally proposed to be related to the work of breathing of patients with respiratory distress.…”

Salbutamol-induced severe lactic acidosis in acute asthma

“…3 Asthma exacerbation can also be associated with several other acid-base disturbances, such as respiratory alkalosis in patients with moderate acute asthma due to hyperventilation leading to hypocapnia and metabolic acidosis. 3 In acute severe asthma, excess blood lactic acid level and lactic acidosis, may result from hypoxemia, hypotension with poor tissue oxygen delivery, overproduction by respiratory muscles performing increased work, metabolic defects caused by liver hypoperfusion, and from drugs such as selective beta-adrenoceptor agonists. 4 In fact, beta-adrenoceptor agonists raise the intracellular concentration of cAMP which allows the activation of glycolysis and lipolysis.…”

Acute Severe Asthma in Adolescent and Adult Patients: Current Perspectives on Assessment and Management

“…Arterial blood gas analysis should be performed on all patients that are critically ill, and/or are desaturating less than 92% despite treatment [212]. By performing arterial blood gas analysis, the clinician will be able to assess not only hypoxemia and the trend of PaCO 2 , but also acid base disturbances, such as respiratory acidosis and lactic acidosis which are common on acute severe asthma [213]. Further investigations may include total white blood cell count, to evaluate the potential of infection, levels of brain natriuretic peptide to exclude the presence of congestive heart failure and electrolyte level measurement.…”