Unveiling the nexus of postoperative fever and delirium in cardiac surgery: identifying predictors for enhanced patient care

A nomogram for predicting delirium in the ICU among older patients with chronic obstructive pulmonary disease

BACKGROUND

Delirium is common among critically ill older patients with chronic obstructive pulmonary disease (COPD). This study aims to develop a nomogram model to predict the risk of ICU delirium in older patients with COPD.

METHODS

This study included 1,912 older COPD patients admitted to the ICU from the MIMIC-IV database. The patients were randomly divided into training and validation sets in a 7:3 ratio. LASSO regression, univariable and multivariable logistic regression were used to select the best predictive factors based on demographic, clinical, laboratory, and treatment data at ICU admission. A nomogram model was then constructed. The model's accuracy was evaluated using calibration curves. Its predictive performance and clinical utility were assessed using the area under the receiver operating characteristic curve (AUC), decision curve analysis (DCA), and clinical impact curves (CIC).

RESULTS

A total of 638 patients (33.4%) developed ICU delirium, with a median age of 76.00 (IQR: 71.00-83.00) years. Ten independent factors were identified for the nomogram model, including cerebrovascular disease (OR: 1.91; 95% CI, 1.38-2.64), Charlson Comorbidity Index (OR: 1.08; 95% CI, 1.02-1.13), Glasgow Coma Scale (OR: 0.82; 95% CI, 0.77-0.87), SOFA score (OR: 1.15; 95% CI, 1.07-1.22), heart rate (OR: 1.01; 95% CI, 1.01-1.02), body temperature (OR: 1.60; 95% CI, 1.14-2.24), blood urea nitrogen (OR: 1.01; 95% CI, 1.00-1.02), 24-hour urine output (OR: 1.02; 95% CI, 1.01-1.02), fentanyl (OR: 1.94; 95% CI, 1.47-2.55), and oxygen flow (OR: 1.04; 95% CI, 1.02-1.07). The model achieved an AUC of 0.86 (95% CI, 0.83-0.90) in the training set and 0.86 (95% CI, 0.84-0.88) in the validation set. The calibration curve showed good agreement between predicted and observed values (P > 0.05). DCA and CIC results indicated the model's strong predictive value and clinical applicability.

CONCLUSIONS

This study developed an intuitive and simple nomogram model to predict the risk of ICU delirium in older patients with COPD. The model can help clinicians quickly identifying high-risk delirium patients upon ICU admission, thereby optimizing early intervention and treatment strategies.

Association Between the Highest Lactate Level on the First Postoperative Day and Postoperative Delirium in Cardiac Surgery Patients

AIMS

The study aimed to determine the correlation between the maximum lactate on the first postoperative day and the incidence of postoperative delirium (POD) in patients after cardiac surgery.

METHODS

The data of cardiac surgery patients were extracted from the Medical Information Mart for Intensive Care IV database. The cut-off value for the first postoperative day maximum lactate was determined, and all patients were categorized into two groups according to the cut-off value. Propensity score matching (PSM) was applied between the two groups, and the difference in the incidence of POD was analyzed. Then, we employed univariate logistic regression, multivariate logistic regression, PSM, and inverse probability of treatment weighting (IPTW) models to examine the relationship between the first postoperative day lactate levels and POD.

RESULTS

Among the 4856 patients enrolled, there was a significant difference in lactate-max on the first postoperative day between patients without POD and patients with POD (median 2.5 vs. 3.1, p < 0.001). The cut-off value of lactate-max was 2.85 mmol/L. For the two groups after PSM, the incidence of POD in the lactate-max ≥ 2.85 mmol/L group was significantly elevated (19.2% vs. 15.9%, p = 0.029). The elevated lactate-max on the first postoperative day was substantially associated with an increased risk of POD in univariate and multivariate logistic regression analyses, PSM, and IPTW models.

CONCLUSIONS

The results demonstrated that the first postoperative day lactate-max was correlated with the risk of POD in patients undergoing cardiac surgery, with the POD risk increasing significantly in patients with a lactate-max ≥ 2.85 mmol/L on the first postoperative day.

Risk factors of delirium after cardiac surgery: a systematic review and meta-analysis

BACKGROUND

Post-operative delirium (POD) is a relatively common occurrence following surgical procedures, particularly cardiac surgeries. Given that the majority of pharmacologic treatments for delirium have demonstrated inadequate efficacy, it is of great importance to identify risk factors to prevent delirium or reduce its complications. Consequently, in this systematic review and meta-analysis, we identified risk factors of POD after cardiac surgery.

METHOD

A comprehensive search of the literature was conducted using the databases Scopus, PubMed, and Web of Science from the inception to April 22, 2024. The objective was to identify prospective cohorts that had assessed the risk factors associated with POD in patients undergoing cardiac surgery using multivariate regression.

RESULTS

Of the 3,166 studies that were initially screened, 23 were included in the review. Nine risk factors were evaluated including age (OR 1.06, 95% CI (1.04, 1.08), p < 0.001), pre-operative depression (OR 3.71, 95% CI (2.45, 5.62), p < 0.001), post-operative atrial fibrillation (AF) (OR 2.39, 95% CI (1.79, 3.21), p < 0.001), hypertension (HTN) (OR 1.64, 95% CI (0.75, 3.56), p = 0.212), age ≥ 65 (OR 3.32, 95% CI (2.40, 4.60), p < 0.001), pre-operative AF (OR 4.43, 95% CI (2.56, 7.69), p < 0.001), diabetes mellitus (OR 2.16, 95% CI (1.39, 3.35), p = 0.001), combined coronary artery bypass graft (CABG) + valve surgery (OR 2.73, 95% CI (1.66, 4.49), p < 0.001), and cardiopulmonary bypass (CPB) time (OR 1.02, 95% CI (1.01, 1.04), p = 0.001).

CONCLUSIONS

A total of nine risk factors were evaluated, from which eight were found to have a statistically significant effect on the risk of developing POD. These factors can be employed to more effectively identify at-risk patients and to prevent the occurrence of POD. Furthermore, this approach can facilitate earlier diagnosis and more effective patient care.

Associations of serum lactate and lactate clearance with delirium in the early stage of ICU: a retrospective cohort study of the MIMIC-IV database

Aim

This study aimed to investigate the associations of serum lactate level [within and after 24 h of the intensive care unit (ICU) admission] and lactate clearance rate with delirium and assess associations of lactate and lactate clearance rate with 30-day mortality in delirium patients.

Methods

Data in this retrospective cohort study were extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database in 2012-2019. The associations of lactate and lactate clearance rate with delirium were explored through univariable and multivariable logistic regression analyses, whereas the associations of lactate and lactate clearance rate with 30-day mortality in delirium patients were investigated using univariable and multivariable Cox regression analyses. Subgroup analysis was performed for age, gender, sepsis, hypertension, sedative drug, ventilation, antibiotic drug, vasopressors, and the Sequential Organ Failure Assessment (SOFA) score. The evaluation indexes were odds ratios (ORs), hazard ratios (HRs), and 95% confidence intervals (CIs).

Results

Among 7,812 (14.58%) eligible participants, 4,338 (8.19%) had delirium and 1,903 (24.36%) died within 30 days. After adjusting for covariates, patients with lactic acidosis (lactate level > 5 mmol/L and PH < 7.35) at T0 (within 24 h of the ICU admission) had higher odds of delirium (OR = 1.235, 95%CI: 1.105-1.382). Hyperlactatemia (lactate level 2-5 mmol/L and PH > 7.35) at T1 (after 24 h of the ICU admission) was also associated with higher odds of delirium (OR = 1.277, 95%CI: 1.126-1.447). Lactate clearance rate > 50% was linked to lower odds of delirium (OR = 0.705, 95%CI: 0.613-0.811), and this relationship was also observed in ≥65 years old, female, male, non-sepsis, sepsis, non-hypertension, non-sedative drug use, sedative drug use, ventilation, antibiotic drug use, use of vasopressors, and different SOFA score subgroups (all p < 0.05). Additionally, hyperlactatemia and lactic acidosis (whether at T0 or T1) may be potential risk factors for 30-day mortality in delirium patients, whereas lactate clearance rate ≥ 0 had a potential protective effect on 30-day mortality (all p < 0.05).

Conclusion

Higher serum lactate levels in the early stage of the ICU were associated with a higher risk of delirium and subsequent mortality. Measures taken to increase the lactate clearance rate are necessary to reduce potential delirium or mortality risk in clinical settings. However, more evidence from prospective studies is needed to verify these findings.