Inhaled β-agonist therapy and respiratory muscle fatigue as under-recognised causes of lactic acidosis

One stone two birds: anti-inflammatory bronchodilators as a potential pharmacological strategy for COVID-19

The ongoing Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has imposed a huge threat to public health across the world. While vaccinations are essential for reducing virus transmission and attenuating disease severity, the nature of high mutation rate of SARS-CoV-2 renders vaccines less effective, urging quick development of effective therapies for COVID-19 disease. However, developing novel drugs remains extremely challenging due to the lengthy process and high cost. Alternatively, repurposing of existing drugs on the market represents a rapid and safe strategy for combating COVID-19 pandemic. Bronchodilators are first line drugs for inflammatory lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Compared to other anti-inflammatory drugs repurposed for COVID-19, bronchodilators are unique in that they have both anti-inflammatory and bronchodilating properties. Whether the dual properties of bronchodilators empower them greater potential to be repurposed for COVID-19 is worth exploring. In fact, clinical and preclinical studies have recently emerged to investigate the benefits of bronchodilators such assalbutamol, formoterol and theophylline in treating COVID-19, and many of them have shown encouraging efficacy on attenuating disease severity of pneumonia and other associated symptoms. To comprehensively understand the latest progress on COVID-19 intervention with bronchodilators, this review will summarize recent findings in this area and highlight the promising clinical benefits and possible adverse effects of bronchodilators as therapeutic options for COVID-19 with a focus on β2 receptor agonists, anticholinergic drugs and theophylline.

Relationships among biochemical measures in children with diabetic ketoacidosis

OBJECTIVES

Investigating empirical relationships among laboratory measures in children with diabetic ketoacidosis (DKA) can provide insights into physiological alterations occurring during DKA. We determined whether alterations in laboratory measures during DKA conform to theoretical predictions.

METHODS

We used Pearson correlation statistics and linear regression to investigate correlations between blood glucose, electrolytes, pH and PCO₂ at emergency department presentation in 1,681 pediatric DKA episodes. Among children with repeat DKA episodes, we also assessed correlations between laboratory measures at the first vs. second episode.

RESULTS

pH and bicarbonate levels were strongly correlated (r=0.64), however, pH and PCO₂ were only loosely correlated (r=0.17). Glucose levels were correlated with indicators of dehydration and kidney function (blood urea nitrogen (BUN), r=0.44; creatinine, r=0.42; glucose-corrected sodium, r=0.32). Among children with repeat DKA episodes, PCO₂ levels tended to be similar at the first vs. second episode (r=0.34), although pH levels were only loosely correlated (r=0.19).

CONCLUSIONS

Elevated glucose levels at DKA presentation largely reflect alterations in glomerular filtration rate. pH and PCO₂ are weakly correlated suggesting that respiratory responses to acidosis vary among individuals and may be influenced by pulmonary and central nervous system effects of DKA.

Albuterol, Acidosis, and Aneurysms

A patient with a complicated medical history on admission for dyspnea was administered nebulizer therapy but after 72 hours developed asymptomatic acute kidney injury and anion-gap metabolic acidosis.

Albuterol-Induced Type B Lactic Acidosis: Not an Uncommon Finding

Lactic acidosis (LA) is usually a medical emergency diagnosed by laboratory evaluation in emergency rooms (ERs) and hospital settings in critically ill patients. LA is classified into two major types based on pathophysiology; type A results from tissue hypoxia and/or hypoperfusion and type B results from deranged metabolic activity in the cells in the absence of hypoxia/hypoperfusion. Prompt evaluation and treatment are essential to prevent morbidity and mortality, especially in patients with type A LA. Most cases of LA are due to type A (hypoperfusion/hypoxia). However, with increased testing of lactic acid levels in ERs and hospitals, we are encountering a few cases of type B LA as well. Diagnosing the exact type is crucial because of differences in management. We here describe a patient with albuterol-induced type B LA, which resolved after discontinuing the albuterol breathing treatments.

[Hyperlactatemia induced by inhaled β2 agonists: An underrecognized side effect. Report of two cases]

BACKGROUND

Repeated use of inhaled β2 agonists is common in asthma or COPD exacerbations. It can lead to hyperlactatemia.

CASE REPORTS

We report two asthmatic patients who presented in the emergency department for an asthma exacerbation. The first patient developed hyperlactatemia at 3.9 mmol/L and the second patient developed hyperlactatemia at 5.6 mmol/L after terbutaline treatment. Both patients had a favorable outcome after adjusting the aerosol dose to clinical parameters.

DISCUSSION

Lactic acidosis induced by the use of inhaled β2 agonists is not synonymous of clinical deterioration. However, this side effect may be complicated by a tachypnea compensating for metabolic acidosis and should be known to avoid unnecessary therapeutic escalation.

1H-NMR-based metabolic profiling of healthy individuals and high-resolution CT-classified phenotypes of COPD with treatment of tiotropium bromide

Background

Heterogeneity of COPD results in different therapeutic effects for different patients receiving the same treatment. COPD patients need to be individually treated according to their own characteristics. The purpose of this study was to explore the differences in different CT phenotypic COPD by molecular metabolites through the use of metabolomics.

Methods

According to the characteristics of CT imaging, 42 COPD patients were grouped into phenotype E (n=20) or phenotype M (n=24). Each COPD patient received tiotropium bromide powder for inhalation for a therapeutic period of 3 months. All subjects were assigned into phenotype E in pre-therapy (EB, n=20), phenotype E in post-therapy (EA, n=20), phenotype M in pre-therapy (MB, n=22), phenotype M in post-therapy (MA, n=22), or normal control (N, n=24). The method of metabolomics based on ¹H nuclear magnetic resonance (¹H-NMR) was used to compare the changes in serum metabolites between COPD patients and normal controls and between different phenotypes of COPD patients in pre- and post-therapy.

Results

Patients with COPD phenotype E responded better to tiotropium bromide than patients with COPD phenotype M in terms of pulmonary function and COPD assessment test scores. There were differences in metabolites in COPD patients vs normal control people. Differences were also observed between different COPD phenotypic patients receiving the treatment in comparison with those who did not receive treatment. The changes of metabolites involved lactate, phenylalanine, fructose, glycine, asparagine, citric acid, pyruvic acid, proline, acetone, ornithine, lipid, pyridoxine, maltose, betaine, lipoprotein, and so on. These identified metabolites covered the metabolic pathways of amino acids, carbohydrates, lipids, genetic materials, and vitamin.

Conclusion

The efficacy of tiotropium bromide on COPD phenotype E is better than that of phenotype M. Metabolites detected by ¹H-NMR metabolomics have potentialities of differentiation of COPD and healthy people, discrimination of different COPD phenotypes, and giving insight into the individualized treatment of COPD.

Metabolomic profiling of doxycycline treatment in chronic obstructive pulmonary disease

Serum metabolic profiling can identify the metabolites responsible for discrimination between doxycycline treated and untreated chronic obstructive pulmonary disease (COPD) and explain the possible effect of doxycycline in improving the disease conditions. ¹H nuclear magnetic resonance (NMR)-based metabolomics was used to obtain serum metabolic profiles of 60 add-on doxycycline treated COPD patients and 40 patients receiving standard therapy. The acquired data were analyzed using multivariate principal component analysis (PCA), partial least-squares-discriminant analysis (PLS-DA), and orthogonal projection to latent structure with discriminant analysis (OPLS-DA). A clear metabolic differentiation was apparent between the pre and post doxycycline treated group. The distinguishing metabolites lactate and fatty acids were significantly down-regulated and formate, citrate, imidazole and l-arginine upregulated. Lactate and folate are further validated biochemically. Metabolic changes, such as decreased lactate level, inhibited arginase activity and lowered fatty acid level observed in COPD patients in response to add-on doxycycline treatment, reflect the anti-inflammatory action of the drug. Doxycycline as a possible therapeutic option for COPD seems promising.

Conundrum in an asthma exacerbation

A 66-year-old man, an asthmatic, presented with symptoms suggestive of an acute exacerbation of asthma. His arterial blood gas revealed type 1 respiratory failure (PaO2 <8 kPa or 60 mm Hg with normal or low PaCO2) with a compensated lactic acidosis. He was treated for an asthma exacerbation and sepsis. Despite treatment, his respiratory rate remained elevated although his hypoxaemia improved. There was progressive worsening of the lactic acidosis. Treatment for sepsis was augmented. Peak flow measurements were not used to assess the severity of his exacerbation nor his response to treatment. An alternate diagnosis of acute coronary syndrome with acute pulmonary oedema was made and his asthma treatment was stopped. This coincided with a decline in his serum lactate. A diagnosis of salbutamol-induced lactic acidosis (SILA) was made. SILA is a relatively common complication of salbutamol therapy in moderate/severe asthma exacerbations. It is caused by a mechanism different from the lactataemia that is associated with septic shock and life-threatening asthma.