Selective ß2-Adrenoceptor Agonists and Relevant Hyperlactatemia: Systematic Review and Meta-Analysis

A Tutorial on Skeletal Muscle Metabolism and the Role of Blood Lactate: Implications for Speech Production

PURPOSE

The purpose of this tutorial is threefold: (a) present relevant exercise science literature on skeletal muscle metabolism and synthesize the limited available research on metabolism of the adult human speech musculature in an effort to elucidate the role of metabolism in speech production; (b) introduce a well-studied metabolic serum biomarker in exercise science, lactate, and the potential usefulness of investigating this metabolite, through a well-established exercise science methodology, to better understand metabolism of the musculature involved in voice production; and (c) discuss exercise physiology considerations for future voice science research that seeks to investigate blood lactate and metabolism in voice physiology in an ecologically valid manner.

METHOD

This tutorial begins with relevant exercise science literature on the basic cellular processes of muscle contraction that require energy and the metabolic mechanisms that regenerate the energy required for task execution. The tutorial next synthesizes the available research investigating metabolism of the adult human speech musculature. This is followed by the authors proposing a hypothesis of speech metabolism based on the voice science literature and the application of well-studied exercise science principles of muscle physiology. The tutorial concludes with a discussion and the potential usefulness of lactate in investigations to better understand the metabolism of the musculature involved in vocal demand tasks.

CONCLUSION

The role of metabolism during speech (respiratory, laryngeal, and articulatory) is an understudied yet critical aspect of speech physiology that warrants further study to better understand the metabolic systems that are used to meet vocal demands.

Asthma and COPD: A Focus on β-Agonists - Past, Present and Future

Asthma has been recognised as a respiratory disorder for millennia and the focus of targeted drug development for the last 120 years. Asthma is one of the most common chronic non-communicable diseases worldwide. Chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality worldwide, is caused by exposure to tobacco smoke and other noxious particles and exerts a substantial economic and social burden. This chapter reviews the development of the treatments of asthma and COPD particularly focussing on the β-agonists, from the isolation of adrenaline, through the development of generations of short- and long-acting β-agonists. It reviews asthma death epidemics, considers the intrinsic efficacy of clinical compounds, and charts the improvement in selectivity and duration of action that has led to our current medications. Important β2-agonist compounds no longer used are considered, including some with additional properties, and how the different pharmacological properties of current β2-agonists underpin their different places in treatment guidelines. Finally, it concludes with a look forward to future developments that could improve the β-agonists still further, including extending their availability to areas of the world with less readily accessible healthcare.

Landscape of short-acting beta-agonists (SABA) overuse in Europe

This review article provides an overview of short-acting beta-agonist (SABA) use and prescribing trends in Europe, summarizing updated data on the results from the industry-funded SABINA program (SABA use IN asthma) and other studies on this matter. SABA use continues to increase worldwide. Overuse has been defined as ≥3 canisters/year. Almost a third of European patients with asthma, at all severity levels, overuse SABA. Guidelines recommend close monitoring of patients who overuse SABA and avoiding over-reliance on SABA monotherapy. SABA overuse is associated with increased risk of asthma exacerbations and mortality, increased use of health services and negative physical and mental health outcomes. Reliance on SABA monotherapy can be unsafe and therefore it is necessary to change asthma treatment approaches and policies. Changes in physician and patient behaviours towards SABA use are required to ensure that patients with asthma are not over-reliant on SABA monotherapy. Notwithstanding, the limitations of the studies on the use of SABA should be considered, taking into account that the prescription/purchase of medication canisters does not always represent the actual use of the medication and that associations between SABA overuse and poor asthma outcomes may not be directly causal. National health systems and asthma guidelines must align asthma management with global recommendations and adjust them to local needs.

Severe lactic acidosis and persistent diastolic hypotension following standard dose of intermittent nebulized salbutamol in a child: a case report

Background

Salbutamol is a selective β2-receptor agonist widely used to treat asthma in both emergency and outpatient settings. However, it has been associated with a broad spectrum of side effects. Lactic acidosis and diastolic hypotension are rarely reported together following intermittent salbutamol nebulization in children, even less so at standard therapeutic doses.

Case presentation

We present the case of a 12-year-old Italian boy, 34 kg body weight, who experienced a serious drug reaction during a moderate asthma exacerbation with associated dehydration (blood urea nitrogen/creatinine 0.25), following intermittent inhaled (0.2 mg at 3-hour intervals—overall 1.4 mg in 24 hours before arrival) and nebulized treatment (3.25 mg at 20-minute intervals in 60 minutes, overall 11.25 mg in our emergency department). The patient developed hyperglycemia (peak concentration 222 mg/dL), hypokalemia (lowest concentration 2.6 mEq/L), electrocardiogram alterations (corrected QT interval 467 ms), long-lasting arterial hypotension despite fluid boluses (lowest value 87/33 mmHg), and elevated blood lactate levels (peak concentration 8.1 mmol/L), following the third nebulized dose. Infections, liver dysfunction, and toxicity following other medications were ruled out. The aforementioned alterations improved within 24 hours after discontinuation of salbutamol.

Conclusions

We reinforce the message that even the use of intermittent nebulized salbutamol for acute moderate asthma can lead to severe transient complications in children. Then, healthcare providers should pay attention not only in emergency settings, to achieve prompt recognition and proper management of this adverse reaction. Careful reassessment could prevent similar reactions.

[Paediatric Life Support]

The European Resuscitation Council (ERC) Paediatric Life Support (PLS) guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations of the International Liaison Committee on Resuscitation (ILCOR). This section provides guidelines on the management of critically ill or injured infants, children and adolescents before, during and after respiratory/cardiac arrest.

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.

European Resuscitation Council Guidelines 2021: Paediatric Life Support

These European Resuscitation Council Paediatric Life Support (PLS) guidelines, are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the management of critically ill infants and children, before, during and after cardiac arrest.

Prevalence and risk factors of lactic acidosis in children with acute moderate and severe asthma, a prospective observational study

Lactic acidosis is a common complication of status asthmaticus in adults. However, data is sparse in children. The aim of this study was to describe the prevalence and risk factors for lactic acidosis in children hospitalised for acute moderate or severe asthma. A total of 154 children 2-17 years of age were enrolled in a prospective observational study conducted in a tertiary hospital. All had capillary blood gas assessment 4 h after the first dose of salbutamol in hospital. The primary endpoint was the prevalence of lactic acidosis. Potential contributing factors such as age, sex, BMI, initial degree of asthma severity, type of salbutamol administration (nebuliser or inhaler), steroids, ipratropium bromide, and glucose-containing maintenance fluid represented secondary endpoints. All in all, 87% of patients had hyperlactatemia (lactate concentration > 2.2 mmol/l). Lactic acidosis (lactate concentration > 5 mmol/l and anion gap ≥ 16 mmol/l) was observed in 26%. In multivariate analysis, age more than 6 years (OR = 2.8, 95% CI 1.2-6.6), glycemia above 11 mmol/l (OR = 3.2 95% CI 1.4-7.4), and salbutamol administered by nebuliser (OR = 10, 95% CI 2.7-47) were identified as risk factors for lactic acidosis in children with moderate or severe asthma.Conclusion: Lactic acidosis is a frequent and early complication of acute moderate or severe asthma in children. What is Known: • Lactic acidosis during acute asthma is associated with b2-mimetics administration. • Salbutamol-related lactic acidosis is self-limited but important to recognise, as compensatory hyperventilation of lactic acidosis can be mistaken for respiratory worsening and lead to inappropriate supplemental bronchodilator administration. What is New: • Lactic acidosis is a frequent complication of acute asthma in the paediatric population. • Age older than 6 years, hyperglycaemia, and nebulised salbutamol are risk factors for lactic acidosis during asthma.

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

Treatment with β2-agonists may cause elevated lactic acid, the end product of anaerobic metabolism of glucose. It has been proposed that lactic acidosis associated with β2-agonists is caused by changes to direct biochemical impacts on glycolysis, gluconeogenesis, pyruvate metabolism, and free fatty acid production. However, much remains unknown, and there is a paucity of evidence regarding the underlying chemical changes associated with this lactic acidosis. The goal of our study was to investigate the impact of 1 hour of continuous albuterol on the untargeted serum metabolome of healthy subjects. Twenty-four healthy participants received 7.5 mg of continuous albuterol for 1 hour. Baseline, 1-hour, and 2-hour lactic acid levels were drawn. Samples obtained at baseline and 1 hour were sent for untargeted metabolomic profiling. Participants had a baseline lactic acid of 1.45 ± 0.46 mmol/L. On average, lactate levels increased 0.33 ± 0.67 mmol/L after 1 hour (P = .02) and remained elevated at 2 hours (0.32 ± 0.72 mmol/L, P = .02), although there was overlap in lactate levels across times. For metabolomic analysis, fatty acids, organic acids, and sugars were elevated, and amino acids were reduced. Lactic acid and pyruvic acid metabolites, however, did not significantly change (after false discovery rate adjustment). In healthy participants, continuous albuterol alters the serum metabolome, but this change may not be clinically significant. The data support recent hypotheses that β2-receptor activation stimulates lactic acid production, altering aerobic glycolysis, gluconeogenesis, and free fatty acid production.

Salbutamol-induced severe lactic acidosis in acute asthma

Selective beta-adrenoceptor agonists are worldwide prescribed to manage bronchial obstruction. However, they expose to a potential risk of hyperlactatemia and lactic acidosis even with normal doses. The mechanism still poorly understood and suggested that salbutamol diverts the metabolism of pyruvate acid from Krebs cycle toward lactate formation. We report the case of a 42-year-old patient, admitted to intensive care unit for acute severe asthma. He presented a transient lactic acidosis over the first 48 h, following an excessive use of salbutamol. The metabolic acidosis caused tachypnea, as a compensatory mechanism, leading to respiratory failure. The diagnosis of salbutamol-induced lactic acidosis must be made by elimination and only accepted after deleting the other causes. The main clinical character is the worsening of dyspnea despite regression of bronchospasm. It is transient and usually normalizes within 24–48 h after stopping or decreasing doses of salbutamol.