66 [58C73] years). in the intensive care unit. SARS-CoV-2 positivity was confirmed by reverse transcription polymerase chain reaction (PCR) using nasopharyngeal and throat swabs. All patients were extubated after a successful spontaneous breathing trial.6 Post-extubation respiratory failure was defined as the need for reintubation or death within 96?h. Laboratory data obtained within 24?h of extubation were collected. We did not use noninvasive ventilation or high-flow nasal cannula oxygen to avoid aerosolizing virus particles. Patients were excluded if they had coinfection such as bacterial, fungal, or viral infection or other differential diagnoses, including thrombosis, heart failure, or aspiration. Patients who never underwent extubation attempts were also excluded. Data on serum SARS-CoV-2 PCR results and SARS-CoV-2 antibodies at extubation were analyzed. Levels of anti-SARS-CoV-2 IgG against nucleocapsid (N), spike S1, AS703026 (Pimasertib) and spike receptor-binding domain (RBD) antigen, and the combination of N and S1 antigens were measured using the iFlash 3000 fully automatic CLIA analyzer (YHLO Biotech Co., Ltd., Shenzhen, China) with a cutoff value of 10 AU/mL. Antibody detection kits against N, AS703026 (Pimasertib) S1, and RBD antigens were obtained from Shenzhen YHLO Biotech Co., Ltd. Cryopreserved sera obtained within 48?h from the time of extubation were included in this analysis. We evaluated factors involved in COVID-19 recurrence. Data are presented as median and interquartile range. The institutional review board approved this study and waived the requirement for informed consent. Twenty-two patients with a confirmed COVID-19 diagnosis required invasive mechanical ventilation in the intensive care unit during the study period. Of 22 patients, 17 who underwent extubation attempts were finally enrolled. All patients were followed up for at least 2 weeks after extubation. Among 17 patients, 4 were women and 13 were men; they had a median age of 72 (61C74) years. Four patients were reintubated for refractory hypoxemia (relapse group) and 13 did not experience post-extubation failure (non-relapse group). The median age was higher in the relapse group than the non-relapse group (76.5 [73C80] years vs. 66 [58C73] years). The median times from symptom onset to intubation were 9.5 (8.75C10.25) days and 11 (9C13) days in the relapse and non-relapse groups, respectively. The median durations of mechanical ventilation were 8 (6.5C10.75) days and AS703026 (Pimasertib) 7 (5C9) days in the relapse and non-relapse groups, respectively. Moreover, there were no significant differences between the groups with respect to sex, body mass index, smoking history, comorbidity, sequential organ failure assessment score at intubation, or treatments, including heparin, dexamethasone, and remdesivir. Although there were no differences between the groups with respect Rabbit Polyclonal to GNRHR to laboratory data such as d-dimer, ferritin, and C-reactive protein levels, lymphocyte counts at extubation were significantly lower in the relapse group than in the non-relapse group (613/L vs. 1046/L; P?=?0.044) (Fig?1 ). Open in a separate window Fig. 1 Box plots showing lymphocyte counts at extubation in patients who did (relapse group) and did not (non-relapse group) experience post-extubation respiratory failure. Lymphocyte counts at extubation were significantly lower in the relapse group than in the non-relapse group (P?=?0.044). Nine patients were evaluated for SARS-CoV-2 IgG at extubation. The median time from symptom onset to blood sample collection was 16 (14C17) days. All nine patients received corticosteroids based on the results of the RECOVERY trial.7 Lymphocyte counts were increased in all patients except one who experienced post-extubation respiratory failure (Fig?2 A). The AS703026 (Pimasertib) relapse group tended to have lower lymphocyte counts and lower levels of SARS-CoV-2 IgG against S1 and RBD at extubation than the non-relapse group (Fig?2B). Among patients who developed post-extubation respiratory failure, one had no antibody response and another had heterogeneous IgG.