PURPOSE: Metabolic acidosis secondary to lactic acidosis may occur in acute, severe asthma and suggests that respiratory muscle fatigue and tissue hypoxia play a major part in the pathogenesis. Non-anion gap metabolic acidosis has also been reported in acute asthma but it's impact on the clinical outcome remains to be evaluated.
METHODS: Arterial blood gases and acid –base profiles were examined retrospectively in 68 adult patients (19 males, 49 females; age range 21 –91: mean age: 44) hospitalized for asthma exacerbation over a nine month period. The relation between acidosis and incidence of intubations was analyzed. Patients with CHF, ESRD, COPD and sepsis were excluded.
RESULTS: Of all patients, 42 (60%) patients had no metabolic acidosis, 19 (28%) patients had non-anion-gap acidosis and 7 (12%) patients had anion-gap acidosis.13 (20%) of all patients were intubated; 8 (62 %) had no metabolic acidosis, 4 (30%) patients had non-anion-gap acidosis and 1 (8%) patient had anion-gap acidosis. Frequency of intubation was 16% in patients with anion-gap acidosis compared with 26% in those with non-anion-gap acidosis.
CONCLUSION: Metabolic acidosis is fairly common in patients with asthma exacerbation, especially non-anion-gap acidosis, which may necessitate the need for more frequent mechanical ventilation.
CLINICAL IMPLICATIONS: More studies are needed to investigate the role of non –anion-gap acidosis in asthma exacerbation.
DISCLOSURE: Ashraf Rashid, None.