Effect of mechanical ventilation and respiratory tract colonization on bronchial immunoglobulin A and G levels in ICU patients

Full text

Objective

The aim of this study was to evaluate the potential effect of mechanical ventilation and colonization of respiratory tract on bronchial IgA and IgG levels.

Patients and methods

Fifteen patients under mechanical ventilation, 10 males and 5 females, sustaining cerebrovascular injury, were included in the study. All patients underwent blood and bronchial immunoglobulin determinations on day 1 (intubation day) and day 4. At the same time bronchial cultures were obtained. None of the patients developed lung infection during the study period.

Results

Mean IgG and IgA plasma levels were 757.72 mg/dl (day 1) 738.81 mg/dl (day 4) and 163.45 mg/dl (day 1), 185.18 mg/dl (day 4), respectively.

Mean IgG and IgA bronchial levels were 35.95 mg/dl (day 1), 29.69 mg/dl (day 4) and 17.84 mg/dl (day 1), 14.76 mg/dl (day 4), respectively. No significant differences were observed between the two measurements of immunoglobulins (day 1,4). In contrast, bronchial cultures were positive (>10⁴ cfu/ml) in 13 out of 15 patients on day 4. Bronchial cultures obtained on day 1 were negative in all the patients.

Conclusion

The colonization of the respiratory tract occurring under mechanical ventilation doesn't alter significantly the bronchial immunoglobulin levels. Although the slight decrease observed may account for the high incidence of pneumonia in ICU patients.