PURPOSE:Despite the initial severity of Acute asphyxial asthma, mechanical ventilation often restores gas exchange promptly, resulting in shorter durations of ventilation.Patients with bronchial hyperresponsiveness seem to have an increased risk of an near-fatal asthma attack. The influence of factors such as airway calibre, bronchial hyperresponsiveness, age and sex on the duration of mechanical ventilation in near-fatal asthma are poorly understood.We were particularly interested to establish whether there was any difference in duration of mechanical ventilation between subjects with a greater or lesser severity of asthma (expressed as bronchial hyperresponsiveness).
METHODS:We retrospectively studies 36 patients previously underwent a histamine provocation test and had an near-fatal asthma(NFA) or fatal asthma(FA) attack and needed mechanical ventilator in ICU.We comprehensively evaluated the association of characteristics of NFA and duration of mechanical ventilation support.Multiple regression analysis was performed to investigate the effect of baseline FEV1, bronchial hyperresponsiveness, smoking status, sex and age on duration of mechanical ventilator support.
RESULTS:36 cases (age: 69.6 ± 14.1 yr) (mean ± SD) were studied.Duration of asthma, gender, smoking status, medications showed no difference in duration mechanical ventilation. There was difference in initial bronchial tone (baseline FEV1) and bronchial hyperresponsiveness (PC20) showed a correlation with duration of mechanical ventilation. The regression coefficients for log PC20 in the multiple regression model were 0.118. Patients who had high bronchial responsiveness to histamine were more likely to show long duration of mechanical ventilator support.
CONCLUSION:High bronchial responsiveness was associated with long duration of mechanical ventilator support. This suggests that patients with a more severe bronchial hyperreponsiveness of asthma show long duration of mechanical ventilator support and fatal asthma.
CLINICAL IMPLICATIONS:Severe bronchial hyperreponsiveness could be a predictor long duration of mechanical ventilator support and fatal asthma.
DISCLOSURE:Kim Hyung Jung, No Financial Disclosure Information; No Product/Research Disclosure Information