Eosinophils in blood and in sputum as predictors of severity in asthmatic crises

Eosinófilos en sangre y en esputo como predictores de severidad en crisis asmática

Some studies have suggested a correlation between eosinophils and greater severity, poorer control of asthma, poorer indexes of lung function, and greater bronchial hyperreactivity as measured by the metacholine challenge test. However, we do not know the behavior of this correlation in Colombia or in the asthma clinic of Hospital San Ignacio. Currently, Wright staining of sputum is interpreted only in the light of the presence of neutrophils, disregarding the value of eosinophils.

Methods: An observational, descriptive, concordance study was carried out over a period of one year, with patients aged 15 years or older, who were admitted through the emergency department with asthmatic crises requiring hospitalization. Severity of the crisis, severity of eosinophils in blood and sputum, peak expiratory flow, duration of hospital stay (in main ward or in ICU), and need for mechanical ventilation were determined in order to define whether there was a correlation between the severity of these variables as predictors of the severity of the asthmatic crisis.

Results: A total number of 169 patients were included, with an age average of 43.3 years, predominantly women (84%), of whom 56.8% were classified as severe and 43.2% as moderate asthmatic crisis. The average of eosinophils in sputum was 17.2% and inblood 375.5 cells per cubic meter. Average length of hospital stay was 4.7 days, 0.5 days in the ICU (only 20 patients required ICU), and 0.2 days on mechanical ventilation. The count of eosinophils in blood was within normal values or highly increased in most patients; most of the patients had slight eosinophilia in sputum.
PEF on admission was, on average, 40% of the optimal. The concordance observed between sputum and blood eosinophils was modest. No correlation was found between severity determined by eosinophils in sputum or blood and length of hospital stay, PEF, or drugs received.

Conclusion: There is no correlation between the levels of eosinophilia found in sputum or blood and the severity of the crisis measured by number of days of hospital stay, days on mechanical ventilation, or value of peak expiratory flow.