[Detection of aspiration of nasopharyngeal secretion and the relationship between the aspiration of nasopharyngeal secretion and the incidence of pneumonia].

OBJECTIVE

To establish a method to detect aspiration of nasopharyngeal secretion and to explore the relationship between aspiration of nasopharyngeal secretion and pneumonia.

METHOD: Thirty-two patients with pulmonary infection [(30 males, 2 females; mean age (73 ± 8) years] were recruited from the First Affiliated Hospital of Guangzhou Medical University during the period between June 2014 and August 2014, and 9 age-matched healthy volunteers [(7 males, 2 females; mean age (73 ± 6) years] as the control group. A dose of 74.0 MBq ⁹⁹Tc(m)-sulfur colloid was diluted in 12 ml of saline, and then the mixture was dripped into the nasal pharynx of volunteers by 24 ml/h. Dynamic imaging from the mouth to the stomach was acquired by SPECT/CT. Two experienced physicians assessed all examination results and reached consensus for final diagnosis. Radioactivity detected at either the bronchi or within the lung fields was reported as positive for aspiration.

RESULTS

In the test group, 19 of 32 patients with pneumonia had a history of suffering from upper respiratory tract symptoms such as runny or blocked nose, and 21 of 32 patients were detected to have aspiration. However, none of the healthy people had aspiration (χ² = 9.624, P=0.002). In 21 patients with pneumonia, 14 showed respiratory aspirations in areas corresponding to the lesions, i.e. bilateral lungs, the right lung and the left lung in 6/10, 6/8, and 2/3 cases respectively (P=0.067).

CONCLUSION

⁹⁹Tc(m)-sulfur colloid imaging is effective to detect the aspiration of nasopharyngeal secretions in the elderly people. Besides, the incidence rate of aspiration in the patients was higher than that in healthy people, which suggests that aspiration of nasopharyngeal secretion is the cause of pulmonary infection.