Lymphocyte and NK Cell Counts Can Predict Sepsis-Associated Delirium in Elderly Patients

Abstract

Background: Sepsis-associated delirium (SAD) is prevalent in elderly patients and is recognized as brain dysfunction associated with increased inflammatory response in the central nervous system during sepsis. Neuroinflammation was demonstrated to be part of its mechanism and we aimed to validate the role of immunity imbalance in a combined retrospective and prospective cohort study.Methods: We performed a retrospective study analyzing the association between SAD and lymphocyte counts in the peripheral blood, alongside a prospective trial evaluating the quantitative changes in lymphocyte subsets and their predictive value for early diagnosis of SAD.Results: In the retrospective study, among 1,010 enrolled adult patients (age ≥65 years), 297 patients were diagnosed with delirium during intensive care unit (ICU) stay and lymphocyte counts at ICU admission in the SAD group were significantly higher than in non-delirious counterparts (1.09 ± 0.32 vs. 0.82 ± 0.24, respectively, p = 0.001). In the prospective study, lymphocyte counts [0.83 (0.56, 1.15) vs. 0.72 (0.40, 1.06) × 109/L, p = 0.020] and natural killer (NK) cell counts [96 (68, 118) vs. 56 (26, 92) cells/μl, p = 0.024] were significantly higher in the SAD group. The area under the curve value of NK cell count was 0.895 [95% confidence interval (CI): 0.857, 0.933] and of lymphocyte count was 0.728 (95% CI: 0.662, 0.795). An NK cell count cut-off value of 87 cells/ml in septic patients at ICU admission was predictive of delirium with a sensitivity of 80.2% and specificity of 80.8%.Conclusions: We found that lymphocyte and NK cell counts were significantly higher in senior patients with SAD and that NK cell count may be valuable for the prediction of SAD within elderly patient cohorts.

Implementation of Nurse-Led, Goal-Directed Lung Physiotherapy for Older Patients With Sepsis and Pneumonia in the ICU

“…The median age of the patients was 72 years (interquartile range: 68–78 years) and 62.1% (157/253) were men. At admission to the ICU, the mean SOFA score was 11.49 ± 3.95, the median APACHE II score was 18 ( 12 – 18 ), and the median CPIS score was 6 ( 5 – 8 ). Ninety-two (36.4%) patients had heart failure, 19 (7.5%) had chronic obstructive pulmonary disease, 74 (29.2%) had diabetes mellitus, 3 (1.2%) had liver cirrhosis, 44(17.4%) with tumors, and 18 (7.1%) had chronic renal failure.…”

“…In this nurse-led GDLPT study, pain assessment, delirium assessment, and active early activities were carried out every 6 h by nurses. Delirium varies from 11 to 42% in older patients and has adverse outcomes and high health care costs ( 18 ). Up to 60% of delirious patients were unrecognized unless actively screened, and sedative medications and deeper sedation are associated with the development of delirium ( 20 ).…”

Immunological risk factors for sepsis-associated delirium and mortality in ICU patients

“…Dongkai Li et al. reported that lymphocyte and NK cell counts were significantly higher in senior patients with SAD, and NK cell count may be valuable for the prediction of SAD within elderly patient cohorts ( 34 ). In our study, we demonstrated that CD14 hi CD16 — monocytes were significantly downregulated in patients with SAD.…”

Early alteration of peripheral blood lymphocyte subsets as a risk factor for delirium in critically ill patients after cardiac surgery: A prospective observational study

“…Peripheral blood samples were collected by PUMCH laboratories at enrollment with EDTA anticoagulant for measurement of lymphocyte counts and immunological biomarkers, as described previously ( Li D. et al, 2020 ). Peripheral blood mononuclear cells were separated, stained with fluorescent monoclonal antibodies, and underwent flow cytometric analysis (3-color EPICSXL flow cytometer; Beckman Coulter, Brea, CA, United States) to detect T cells (CD3 + ), CD4 + T cells (CD4 + CD3 + and CD28 + CD4 + ), CD8 + T cells (CD8 + CD3 + , CD28 + CD8 + ), B cells (CD19 + ), and natural killer cells (CD3 – CD16 + CD56 + ).…”