Abstract:Objective To explore the effect of fiberoptic bronchoscope sputum suctioning combined with linezolid on sputum culture conversion rate and infection related biomarkers in patients with severe pulmonary infection (SPI).Methods The subjects of this study, 104 patients from January 2022 to October 2023, were randomly divided into two groups, each with 52 cases. The observation group was treated with fiberoptic bronchoscope sputum suctioning combined with linezolid, while the control group was administrated with merely linezolid. The sputum culture negative conversion rate, disappearance time of symptoms (fever, expectoration, cough and lung rale), blood gas indicators [oxygen saturation in arterial blood (SaO2), partial pressure of oxygen in arterial blood (PaO2), partial pressure of carbon dioxide in arterial blood (PaCO2), and oxygenation index (OI)] before and after treatment, levels of infection related biomarkers [procalcitonin (PCT), peripheral blood neutrophil to lymphocyte ratio (NLR), interleukin-6 (IL-6), soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and soluble urokinase type plasminogen activator receptor (suPAR)], clinical pulmonary infection score (CPIS), acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) before and after treatment, and the adverse reactions were recorded in two groups.Results The total effective rate and sputum culture clearance rate of the observation group were 90.38% (47/52) and 86.54% (45/52) respectively, significant higher than those of the control group [75.00% (39/52) and 65.38% (34/52)], the differences were statistically significant (P < 0.05). The disappearance time of symptoms (fever, expectoration, cough and lung rale) in observation group was significant shorter than that in control group, the difference was statically significant (P < 0.05). After treatment, PaO2, SaO2, and OI in two groups were significant higher than those before treatment, and the observation group was significantly higher than the control group, the PaCO2, peripheral blood NLR, serum PCT, IL-6, sTREM-1, suPAR levels, CPIS and APACHE Ⅱ scores were lower than those before treatment, and observation group was lower than control group, the differences were statistically significant (P < 0.05). The incidence of adverse reaction was 15.38% (8/52) in observation group and 17.31% (9/52) in control group, the difference was not statistically significant (P > 0.05).Conclusion In treating SPI patients, the combination of fiberoptic bronchoscope sputum suctioning and linezolid can effectively downregulate the levels of infection related biomarkers in patients, improve the sputum culture clearance rate and clinical efficacy.