Trong dài hạn tiếp theo, thủ tục phẫu thuật mới cần thiết lên đến 25% bệnh nhân (20,21). Thành công ESS cung cấp cải tiến trong đánh bại tiêm mao niêm mạc (22,23), trong khi sẹo tắc nghẽn ostial đã nhiều lần được xác định là một biến chứng phẫu thuật có ý nghĩa ở phẫu thuật sửa đ | Nosocomial Sinusitis 321 first time failure rates between 5 and 10 . In long-term follow-ups new surgical procedures are necessary in up to 25 of the patients 20 21 . Successful ESS provides improvement in the mucosal ciliary beat 22 23 while scarring with ostial obstruction has repeatedly been identified as a significant surgical complication at revision surgery 20 23-25 . The Nosocomial Bacterial Flora The patient s indigenous bacterial flora may cause infections although the bacterial reservoir in the ICU represents an even higher potential risk. Hospitalized patients rapidly become colonized or infected by the ICU flora which is strongly influenced by the selective pressure caused by antimicrobial agents that are used 26-28 . In addition the therapeutic measures utilized in the patient such as use of invasive devices and immunomodulating therapy may enhance the predisposition to infection. Infectious sinusitis in this setting is caused by bacteria and occasionally by fungi. However the etiology of paranasal sinus during an ICU stay is not only infectious. There are inflammatory conditions varying from noninfectious sinusitis that does not contain bacteria to noninfectious sinusitis with bacteria that only represent colonization 29 . Body Position When lying down our otherwise upward-directed blood vessels fill better since their direction has changed. When a healthy individual assumes a recumbent position the blood vessels in the rhinosinus region become engorged thus leading to mucosal edema with a significant reduction in the patency of the antral ostiae 30 31 . An inflammatory reaction in the mucosa due to allergy or the common cold also increases the nasal airflow resistance up to three times in the horizontal position as compared to the resistance in a healthy individual 32 33 . The full significance of the general edema in the rhinosinuses of critically ill patients is not fully understood. Even so it is common practice in the ICU to position the patient
