BackgroundPostoperative delirium (POD) is an acute brain dysfunction that is frequently observed in patients undergoing cardiac surgery. Increasing evidence indicates POD is related to higher mortality among cardiac surgical patients, but the results remain controversial. Moreover, a quantitative evaluation of the influence of POD on hospital days, intensive care unit (ICU) time, and mechanical ventilation (MV) time has not been performed.ObjectiveThis study aimed to evaluate the correlation between POD and outcomes in patients undergoing cardiac surgery by a systematic review and meta-analysis.Materials and methodsA total of 7 electronic databases (Cochrane Library, PubMed, EMBASE, CINAHL Complete, MEDLINE, Wan-fang database, and China National Knowledge Infrastructure) were searched from January 1980 to July 20, 2021, with language restrictions to English and Chinese, to estimate the impact of the POD on outcome in patients who underwent cardiac surgery. The meta-analysis was registered with PROSPERO (Registration: CRD42021228767).ResultsForty-two eligible studies with 19785 patients were identified. 3368 (17.0%) patients were in the delirium group and 16417 (83%) were in the non-delirium group. The meta-analysis showed that compared to patients without POD, patients with POD had 2.77-fold higher mortality (OR = 2.77, 95% CI 1.86–4.11, P < 0.001), 5.70-fold higher MV (>24h) rate (OR = 5.70, 95% CI 2.93–11.09, P < 0.001); and longer MV time (SMD = 0.83, 95% CI 0.57–1.09, P < 0.001), ICU time (SMD = 0.91, 95% CI 0.60–1.22, P < 0.001), hospital days (SMD = 0.62, 95% CI 0.48–0.76, P < 0.001).ConclusionThe synthesized evidence suggests that POD is causally related to the increased risk of mortality, prolonged length of ICU and hospital stay, and a longer duration of MV time. Future research should focus on the interventions for POD, to reduce the incidence.Systematic review registration[www.crd.york.ac.uk/PROSPERO], identifier [CRD42021228767].

Background Studies suggest that high-flow nasal cannula (HFNC) and non-invasive ventilation (NIV) can prevent reintubation in critically ill patients with a low risk of extubation failure. However, the safety and effectiveness in patients at high risk of extubation failure are still debated. Therefore, we conducted a systematic review and meta-analysis to compare the efficacies of HFNC and NIV in high-risk patients. Methods We searched eight databases (MEDLINE, Cochrane Library, EMBASE, CINAHL Complete, Web of Science, China National Knowledge Infrastructure, Wan-Fang Database, and Chinese Biological Medical Database) with reintubation as a primary outcome measure. The secondary outcomes included mortality, intensive care unit (ICU) length of stay (LOS), incidence of adverse events, and respiratory function indices. Statistical data analysis was performed using RevMan software. Results Thirteen randomized clinical trials (RCTs) with 1457 patients were included. The HFNC and NIV groups showed no differences in reintubation (RR 1.10, 95% CI 0.87–1.40, I2 = 0%, P = 0.42), mortality (RR 1.09, 95% CI 0.82–1.46, I2 = 0%, P = 0.54), and respiratory function indices (partial pressure of carbon dioxide [PaCO2]: MD − 1.31, 95% CI − 2.76–0.13, I2 = 81%, P = 0.07; oxygenation index [P/F]: MD − 2.18, 95% CI − 8.49–4.13, I2 = 57%, P = 0.50; respiratory rate [Rr]: MD − 0.50, 95% CI − 1.88–0.88, I2 = 80%, P = 0.47). However, HFNC reduced adverse events (abdominal distension: RR 0.09, 95% CI 0.04–0.24, I2 = 0%, P < 0.01; aspiration: RR 0.30, 95% CI 0.09–1.07, I2 = 0%, P = 0.06; facial injury: RR 0.27, 95% CI 0.09–0.88, I2 = 0%, P = 0.03; delirium: RR 0.30, 95%CI 0.07–1.39, I2 = 0%, P = 0.12; pulmonary complications: RR 0.67, 95% CI 0.46–0.99, I2 = 0%, P = 0.05; intolerance: RR 0.22, 95% CI 0.08–0.57, I2 = 0%, P < 0.01) and may have shortened LOS (MD − 1.03, 95% CI − 1.86–− 0.20, I2 = 93%, P = 0.02). Subgroup analysis by language, extubation method, NIV parameter settings, and HFNC flow rate revealed higher heterogeneity in LOS, PaCO2, and Rr. Conclusions In adult patients at a high risk of extubation failure, HFNC reduced the incidence of adverse events but did not affect reintubation and mortality. Consequently, whether or not HFNC can reduce LOS and improve respiratory function remains inconclusive.

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Background: Accumulated studies have revealed that heart rates are associated with all-cause mortality in cardiac surgery patients, but the results remain controversial. This meta-analysis aimed to evaluate the predictive value of increased perioperative heart rate for all-cause mortality after cardiac surgery. Methods: We searched PubMed, Embase, Web of Science, and Cumulative Index of Nursing and Allied Health Literature (CINAHL) databases for studies from inception to October 11, 2021. Two researchers independently screened the studies. Titles, authors, publication years, and hazard ratios were extracted. We used a random-effects model to combine the HRs and 95% confidence intervals. Several subgroup analyses were conducted. Statistical significance was set at p < .05. Results: Eleven studies were included in the meta-analysis of 33,849 patients and 3166 (9.4%) deaths. The HR of higher perioperative heart rates was 2.09 (95% CI 1.53–2.86, p < .001, I2 = 81%). The HR with a 10-bpm increase in preoperative heart rate was 1.19 (95% CI 1.11–1.26, p < .001, I2 = 51%). Subgroup analysis showed patients with higher preoperative heart rates had an HR of 1.88 (95% CI 1.51–2.34, p < .001, I2 = 0%), and patients with a higher postoperative heart rate had an HR of 2.29 (95% CI 1.28– 4.09, p < .0001, I2 = 91%) compared to patients with lower postoperative heart rates. Conclusion: Increased perioperative heart rate is associated with all-cause mortality in patients undergoing cardiac surgery.

SummaryPostoperative delirium (POD) is a very common neurological complication after valve surgery. Some studies have shown that preoperative sleep disorder is associated with POD, but the correlation between preoperative slow wave sleep (SWS) and POD remains unclear. Therefore, this study aims to identify the correlation between preoperative slow wave sleep and postoperative delirium in patients with heart valve disease. This was a prospective, observational study of elective valve surgery patients admitted to the Heart Medical Center between November 2021 and July 2022. Polysomnography (PSG) was used to monitor sleep architecture from 9:30 p.m. for 1 night before surgery to 6:30 a.m. on the day of surgery. Patients were assessed for postoperative delirium from postoperative day 1 to extubation or day 5 by using the Richmond Agitation/Sedation Scale (RASS) and the Confusion Assessment Method for the Intensive Care Unit (CAM‐ICU). A total of 60 elective valve surgery patients were enrolled in this study. Prolonged N1 (11.44%) and N2 (58.62%) sleep, decreased N3 sleep (8.75%) and REM sleep (18.24%) within normal limits were the overall sleep architecture. Compared with patients without POD, patients with POD had less slow wave sleep 1 night before surgery (5.77% vs 10.88%, p < 0.001). After adjusting for confounding factors, slow wave sleep (OR: 0.647, 95% CI 0.493–0.851, p = 0.002) was found to be a protective factor for postoperative delirium. The preoperative SWS is a predictive factor of the POD in patients undergoing valve surgery. But further studies with larger sample sizes are still needed to elucidate the relationship between preoperative slow wave sleep and postoperative delirium.