Salbutamol: beware of the paradox!

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.

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

Selective ß₂-agonists have been imputed as potential cause of l-hyperlactatemia since the 1970s. To document the prevalence of hyperlactatemia associated with selective ß₂-agonists and to investigate the predisposing factors, we searched for published articles until April 2019 pertaining to the interplay of administration of selective ß₂-agonists and circulating l-lactic acid in the Excerpta Medica, Web of Science, and the U.S. National Library of Medicine databases. Out of the 1834 initially retrieved records, 56 articles were included: 42 papers reporting individual cases, 2 observational studies, and 12 clinical trials. Forty-seven individual patients receiving a selective ß₂-agonist were found to have l-lactatemia ≥5.0 mmol/L, which decreased by ≥3.0 mmol/L or to ≤2.5 mmol/L after discontinuing (N = 24), reducing (N = 17) or without modifying the dosage of the selective ß₂-agonist (N = 6). Clinical trials found that l-lactic acid significantly increased in healthy volunteers administered a ß₂-agonist. l-lactatemia ≥5.0 mmol/L was observed in 103 (24%) out of 426 patients with asthma or preterm labor managed with a selective ß₂-agonist and was more common in patients with asthma (30%) than in premature labor (5.9%). A significant relationship was also noted between l-lactate level and intravenous albuterol dose or its circulating level. In conclusion, relevant l-hyperlactatemia is common on high dose treatment with a selective ß₂-agonist.

[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.

Adverse event notifications implicating metformin with lactic acidosis in Australia

OBJECTIVE

To summarise the reported lactic acidosis cases associated with metformin from the Australian Therapeutic Goods Administration (TGA) and estimate the incidence of metformin-associated lactic acidosis (MALA) in Australia.

METHOD

All "lactic acidosis" cases associated with metformin and reported to the TGA between January 1971 and October 2014 were included. Data extracted included patient demographics, medical history and co-existing conditions, metformin dosage and relevant pathology results.

RESULT

A total of 152 cases of suspected MALA were included in this study. For 20 patients the outcome was unknown. There were 23 patients (n=132, 17.4%) reported as deceased. Plasma lactate levels were higher in non-survivors (p=0.02). Thirty-five patients (n=132, 26.5%) were reported to have at least one pre-existing contraindication to the use of metformin; this proportion was not different between patients who died or survived. Renal impairment was the most common contraindication. Approximately 75% of patients were reported to have at least one clinical condition which might cause acidosis. Metformin dosage, plasma lactate and serum creatinine were not correlated. Based on the cases reported to the TGA, the incidence of MALA in Australia was estimated to be 2.3 (95% CI, 1.5-3.1) cases per 100,000 patient-years between 1997 and 2011.

CONCLUSION

Pre-existing clinical conditions, such as renal impairment, and acute illnesses associated with lactic acidosis were frequently reported in the cases of MALA. The estimated incidence of MALA was lower than in most previous studies in other countries, probably due to the nature of spontaneous reports to the TGA.