Association of perioperative transfusion of fresh frozen plasma and outcomes after cardiac surgery.

BACKGROUND: Fresh frozen plasma (FFP) transfusion is used to manage coagulopathy and bleeding in cardiac surgery patients despite uncertainty about its safety and effectiveness. METHODS: We performed a propensity score matched analysis of the Australian and New Zealand Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database including patients from 39 centres from 2005 to 2018. We investigated the association of perioperative FFP transfusion with mortality and other clinical outcomes. RESULTS: Of 119,138 eligible patients, we successfully matched 13,131 FFP recipients with 13,131 controls. FFP transfusion was associated with 30-day mortality (odds ratio (OR), 1.41; 99% CI, 1.17-1.71; p < .0001), but not with long-term mortality (hazard ratio (HR), 0.92; 99% CI, 0.85-1.00; p = .007, Holm-Bonferroni α = 0.0004). FFP was also associated with return to theatre for bleeding (OR, 1.97; 99% CI, 1.66-2.34; p < .0001), prolonged intubation (OR, 1.15; 99% CI, 1.05-1.26; p < .0001) and increased chest tube drainage (Mean difference (MD) in mL, 131; 99% CI, 120-141; p < .0001). It was also associated with reduced postoperative creatinine levels (MD in g/L, -6.33; 99% CI, -10.28 to -2.38; p < .0001). CONCLUSION: In a multicentre, propensity score matched analysis, perioperative FFP transfusion was associated with increased 30-day mortality and had variable associations with secondary clinical outcomes.

Sex Differences in Opioid Administration After Cardiac Surgery.

OBJECTIVES: To assess whether there are sex-based differences in the administration of opioid analgesic drugs among inpatients after cardiac surgery. DESIGN: A retrospective cohort study. SETTING: At a tertiary academic referral center. PARTICIPANTS: Adult patients who underwent cardiac surgery from 2014 to 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the cumulative oral morphine equivalent dose (OMED) for the postoperative admission. Secondary outcomes were the daily difference in OMED and the administration of nonopioid analgesics. The authors developed multivariate regression models controlling for known confounders, including weight and length of stay. A total of 3,822 patients (1,032 women and 2,790 men) were included. The mean cumulative OMED was 139 mg for women and 180 mg for men, and this difference remained significant after adjustment for confounders (adjusted mean difference [aMD], -33.21 mg; 95% CI, -47.05 to -19.36 mg; p < 0.001). The cumulative OMED was significantly lower in female patients on postoperative days 1 to 5, with the greatest disparity observed on day 5 (aMD, -89.83 mg; 95% CI, -155.9 to -23.80 mg; p = 0.009). By contrast, women were more likely to receive a gabapentinoid (odds ratio, 1.91; 95% CI, 1.42-2.58; p < 0.001). The authors found no association between patient sex and the administration of other nonopioid analgesics or specific types of opioid analgesics. The authors found no association between patient sex and pain scores recorded within the first 48 hours after extubation, or the number of opioids administered in close proximity to pain assessments. CONCLUSIONS: Female sex was associated with significantly lower amounts of opioids administered after cardiac surgery.

Platelet versus fresh frozen plasma transfusion for coagulopathy in cardiac surgery patients.

BACKGROUND: Platelets (PLTS) and fresh frozen plasma (FFP) are often transfused in cardiac surgery patients for perioperative bleeding. Their relative effectiveness is unknown. METHODS: We conducted an entropy-weighted retrospective cohort study using the Australian and New Zealand Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database. All adults undergoing cardiac surgery between 2005-2021 across 58 sites were included. The primary outcome was operative mortality. RESULTS: Of 174,796 eligible patients, 15,360 (8.79%) received PLTS in the absence of FFP and 6,189 (3.54%) patients received FFP in the absence of PLTS. The median cumulative dose was 1 unit of pooled platelets (IQR 1 to 3) and 2 units of FFP (IQR 0 to 4) respectively. After entropy weighting to achieve balanced cohorts, FFP was associated with increased perioperative (Risk Ratio [RR], 1.63; 95% Confidence Interval [CI], 1.40 to 1.91; P<0.001) and 1-year (RR, 1.50; 95% CI, 1.32 to 1.71; P<0.001) mortality. FFP was associated with increased rates of 4-hour chest drain tube output (Adjusted mean difference in ml, 28.37; 95% CI, 19.35 to 37.38; P<0.001), AKI (RR, 1.13; 95% CI, 1.01 to 1.27; P = 0.033) and readmission to ICU (RR, 1.24; 95% CI, 1.09 to 1.42; P = 0.001). CONCLUSION: In perioperative bleeding in cardiac surgery patient, platelets are associated with a relative mortality benefit over FFP. This information can be used by clinicians in their choice of procoagulant therapy in this setting.

Platelet Transfusion in Cardiac Surgery: An Entropy-Balanced, Weighted, Multicenter Analysis.

BACKGROUND: Platelet transfusion is common in cardiac surgery, but some studies have suggested an association with harm. Accordingly, we investigated the association of perioperative platelet transfusion with morbidity and mortality. METHODS: We conducted a retrospective analysis of prospectively collected data from the Australian Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database. We included consecutive adults from 2005 to 2018 across 40 centers. We used inverse probability of treatment weighting via entropy balancing to investigate the association of perioperative platelet transfusion with our 2 primary outcomes, operative mortality (composite of both 30-day and in-hospital mortality) and 90-day mortality, as well as multiple other clinically relevant secondary outcomes. RESULTS: Among 119,132 eligible patients, 25,373 received perioperative platelets and 93,759 were considered controls. After entropy balancing, platelet transfusion was associated with reduced operative mortality (odds ratio [OR], 0.63; 99% confidence interval [CI], 0.47-0.84; P < .0001) and 90-day mortality (OR, 0.66; 99% CI, 0.51-0.85; P < .0001). Moreover, it was associated with reduced odds of deep sternal wound infection (OR, 0.57; 99% CI, 0.36-0.89; P = .0012), acute kidney injury (OR, 0.84; 99% CI, 0.71-0.99; P = .0055), and postoperative renal replacement therapy (OR, 0.71; 99% CI, 0.54-0.93; P = .0013). These positive associations were observed despite an association with increased odds of return to theatre for bleeding (OR, 1.55; 99% CI, 1.16-2.09; P < .0001), pneumonia (OR, 1.26; 99% CI, 1.11-1.44; P < .0001), intubation for longer than 24 hours postoperatively (OR, 1.13; 99% CI, 1.03-1.24; P = .0012), inotrope use for >4 hours postoperatively (OR, 1.14; 99% CI, 1.11-1.17; P < .0001), readmission to hospital within 30 days of surgery (OR, 1.22; 99% CI, 1.11-1.34; P < .0001), as well as increased drain tube output (adjusted mean difference, 89.2 mL; 99% CI, 77.0 mL-101.4 mL; P < .0001). CONCLUSIONS: In cardiac surgery patients, perioperative platelet transfusion was associated with reduced operative and 90-day mortality. Until randomized controlled trials either confirm or refute these findings, platelet transfusion should not be deliberately avoided when considering odds of death.

Fresh frozen plasma transfusion after cardiac surgery.

INTRODUCTION: Fresh frozen plasma (FFP) transfusion in the intensive care unit (ICU) is commonly used to treat coagulopathy and bleeding in cardiac surgery, despite suggestion that it may increase the risk of morbidity and mortality through mechanisms such as fluid overload and infection. METHODS: We retrospectively studied consecutive adults undergoing cardiac surgery from the Medical Information Mart for Intensive Care III and IV databases. We applied propensity score matching to investigate the independent association of within-ICU FFP transfusion with mortality and other key clinical outcomes. RESULTS: Of our 12,043 adults who met inclusion criteria, 1585 (13.2%) received perioperative FFP with a median of 2.48 units per recipient (interquartile range [IQR]: 2.04, 4.33) at a median time of 1.83 h (IQR: 0.75, 3.75) after ICU admission. After propensity matching of 952 FFP recipients to 952 controls, we found no significant association between FFP use and hospital mortality (odds ratio (OR): 1.58; 99% confidence interval (CI): 0.57, 3.71), suspected infection (OR: 0.72; 99% CI: 0.49, 1.08), or acute kidney injury (OR: 1.23; 99% CI: 0.91, 1.67). However, FFP was associated with increased days in hospital (adjusted mean difference (AMD): 1.28; 99% CI: 0.27, 2.41; p = .0050), days in intensive care (AMD: 1.28; 99% CI: 0.27, 2.28; p = .0011), and chest tube output in millilitres up to 8 h after transfusion (AMD: 92.98; 99% CI: 52.22, 133.74; p < .0001). CONCLUSIONS: After propensity matching, FFP transfusion was not associated with increased hospital mortality, but was associated with increased length of stay and no decrease in bleeding in the early post-transfusion period.

Association of Perioperative Cryoprecipitate Transfusion and Mortality After Cardiac Surgery.

BACKGROUND: Cryoprecipitate is often transfused in patients undergoing cardiac surgery. However, its safety and effectiveness remain uncertain. METHODS: This study was a propensity score-matched analysis of data from the Australian and New Zealand Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database. The study included adults undergoing cardiac surgery between 2005 and 2018 across 38 sites. The association between perioperative cryoprecipitate transfusion and clinical outcomes was estimated, with a primary outcome of operative mortality. RESULTS: Of 119,132 eligible patients, 11,239 (9.43%) patients received cryoprecipitate. The median cumulative dose was 8 U (interquartile range, 5-10 U). After propensity score matching, we matched 9055 cryoprecipitate recipients to 9055 control subjects. Postoperative cryoprecipitate transfusion was associated with reduced operative mortality (odds ratio [OR], 0.82; 99% CI, 0.69-0.97; P = .002) and long-term mortality (hazard ratio, 0.92; 99% CI, 0.87-0.97; P = .0042). It was also associated with a reduction in acute kidney injury (OR, 0.85; 99% CI, 0.73-0.98; P = .0037) and all-cause infection (OR, 0.77; 99% CI, 0.67-0.88; P < .0001). These findings were observed despite increased rates of return to the operating room (OR, 1.36; 99% CI, 1.22-1.51; P < .0001) and cumulative 4-hour postoperative chest tube output (adjusted mean difference in mL, 97.69; 99% CI, 81.65;113.74; P < .0001). CONCLUSIONS: In a large, multicenter cohort study and after propensity score matching, perioperative transfusion of cryoprecipitate was associated with reduced operative and long-term mortality.

The Prognostic Significance of Red Cell Distribution Width in Cardiac Surgery: A Systematic Review and Meta-Analysis.

RED CELL DISTRIBUTION WIDTH (RDW) is a routinely available biomarker of likely erythropoietic dysfunction, which may be associated with adverse outcomes after cardiac surgery. This systematic review and meta-analysis aimed to clarify the prognostic value of RDW in patients undergoing cardiac surgery. The authors searched MEDLINE, Embase, and the Cochrane Library from inception to May 10, 2022 for studies investigating the association between elevated RDW (as defined by the authors of included studies) and adverse outcomes after cardiac surgery. Herein, the authors extracted maximally adjusted hazard ratios (HRs) and odds ratios (ORs) with associated CIs, and pooled them using random-effects inverse- variance modeling. The authors explored interstudy heterogeneity using metaregression. The authors included 26 studies involving 48,092 patients who had undergone cardiac surgery. Elevated preoperative RDW was associated with long-term mortality (pooled HR 1.63, 95% CI 1.05-2.52), short-term mortality (pooled OR 2.16, 95% CI 1.21-3.87), acute kidney injury (AKI; pooled OR 1.30, 95% CI 1.19-1.41) and postoperative atrial fibrillation (POAF; pooled OR 1.44, 95% CI 1.05-1.96). Some studies suggested a significant association between preoperative RDW elevation and neurologic complications; however, their number was insufficient for meta-analysis. The postoperative RDW levels were less consistently reported and could not be meta-analyzed. In conclusion, the authors found that elevated preoperative RDW was associated with increased short- and long-term mortality, POAF, and AKI after cardiac surgery. Further research is needed to investigate its role in the risk stratification of patients undergoing cardiac surgery.

Platelet Transfusion After Cardiac Surgery.

OBJECTIVES: To investigate the independent association of platelet transfusion with hospital mortality and key relevant clinical outcomes in cardiac surgery. DESIGN: A single-center, propensity score-matched, retrospective, cohort study. SETTING: At an American tertiary teaching hospital data from the Medical Information Mart for Intensive Care III and IV databases from 2001 to 2019. PARTICIPANTS: Consecutive adults undergoing coronary artery bypass graft and/or cardiac valvular surgery. INTERVENTIONS: Platelet transfusion during perioperative intensive care unit (ICU) admission. MEASUREMENTS AND MAIN RESULTS: Overall, 12,043 adults met the study inclusion criteria. Of these, 1,621 (13.5%) received apheresis-leukoreduced platelets, with a median of 1.19 units per recipient (IQR: 0.93-1.19) at a median of 1.78 hours (IQR: 0.75-4.25) after ICU admission. The platelet count was measured in 1,176 patients (72.5%) before transfusion, with a median count of 120 × 109/L (IQR: 89.0-157.0), and only 53 (3.3%) had platelet counts below 50 × 109/L. After propensity matching of 1,046 platelet recipients with 1,046 controls, perioperative platelet transfusion carried no association with in-hospital mortality (odds ratio [OR]: 1.28; 99% CI: 0.49-3.35; p = 0.4980). However, it was associated with a pattern of decreased odds of suspected infection (eg, respiratory infection, urinary tract infection, septicaemia, or other; OR: 0.70; 99% CI: 0.50-0.97; p = 0.0050), days in the hospital (adjusted mean difference [AMD]: 0.86; 99% CI: -0.27 to 1.98; p = 0.048), or days in intensive care (AMD 0.83; 99% CI: -0.15 to 1.82; p = 0.0290). CONCLUSIONS: Platelet transfusion was not associated with hospital mortality, but it was associated with decreased odds of suspected infection and with shorter ICU and hospital stays.

Cryoprecipitate Transfusion After Cardiac Surgery.

OBJECTIVES: The association of cryoprecipitate transfusion with patient outcomes after cardiac surgery is unclear. We aimed to investigate the predictors of, and outcomes associated with, postoperative cryoprecipitate transfusion in cardiac surgery patients. METHODS: We used the Medical Information Mart for Intensive Care III and IV databases. We included adults undergoing cardiac surgery, and propensity score matched cryoprecipitate-treated patients to controls. Using the matched cohort, we investigated the association of cryoprecipitate use with clinical outcomes. The primary outcome was in-hospital mortality. Secondary outcomes were infection, acute kidney injury, intensive care unit length of stay, hospital length of stay, and chest tube output at 2-hour intervals. RESULTS: Of 12,043 eligible patients, 283 (2.35%) patients received cryoprecipitate. The median dose was 5.83 units (IQR 4.17-7.24) given at a median first transfusion time of 1.75 hours (IQR 0.73-4.46) after intensive care unit admission. After propensity scoring, we matched 195 cryoprecipitate recipients to 743 controls. Postoperative cryoprecipitate transfusion was not significantly associated with in-hospital mortality (odds ratio [OR] 1.10; 99% confidence interval [CI] 0.43-2.84; p=0.791), infection (OR 0.77; 99% CI 0.45-1.34; p=0.220), acute kidney injury (OR 1.03; 99% CI 0.65-1.62; p=0.876) or cumulative chest tube output (adjusted mean difference 8 hrs post transfusion, 11 mL; 99% CI -104 to 125; p=0.804). CONCLUSIONS: Although cryoprecipitate was typically given to sicker patients with more bleeding, its administration was not associated with worse outcomes. Large, multicentred studies are warranted to further elucidate cryoprecipitate's safety profile and patterns of use in cardiac surgery.

The prognostic value of elevated neutrophil-lymphocyte ratio for cardiac surgery-associated acute kidney injury: A systematic review and meta-analysis.

BACKGROUND: Patients undergoing cardiac surgery are at significant risk of developing postoperative acute kidney injury (AKI). Neutrophil-lymphocyte ratio (NLR) is a widely available inflammatory biomarker which may be of prognostic value in this setting. METHODS: We conducted a systematic review and meta-analysis of studies reporting associations between perioperative NLR with postoperative AKI. We searched Medline, Embase and the Cochrane Library, without language restriction, from inception to May 2022 for relevant studies. We meta-analysed the reported odds ratios (ORs) with 95% confidence intervals (CIs) for both elevated preoperative and postoperative NLR with risk of postoperative AKI and need for renal replacement therapy (RRT). We conducted a meta-regression to explore inter-study statistical heterogeneity. RESULTS: Twelve studies involving 10,724 participants undergoing cardiac surgery were included, with eight studies being deemed at high risk of bias using PROBAST modelling. We found statistically significant associations between elevated preoperative NLR and postoperative AKI (OR 1.45, 95% CI 1.18-1.77), as well as postoperative need for RRT (OR 2.37, 95% CI 1.50-3.72). Postoperative NLR measurements were not of prognostic significance. CONCLUSIONS: Elevated preoperative NLR is a reliable inflammatory biomarker for predicting AKI following cardiac surgery.

Epidemiology of persistent postoperative opioid use after cardiac surgery: a systematic review and meta-analysis.

BACKGROUND: The epidemiology of persistent postoperative opioid use at least 3 months after cardiac surgery is poorly characterised despite its potential public health importance. METHODS: We searched MEDLINE, Embase, and Google Scholar from inception to December 2021 and included studies reporting the rate and risk factors of persistent postoperative opioid use after cardiac surgery in opioid-naive and opioid-exposed patients. We recorded incidence rates and odds ratios (ORs) with 95% confidence intervals (CIs) for risk factors from individual studies and used random-effects inverse variance modelling to generate pooled estimates. RESULTS: From 10 studies involving 112 298 patients, the pooled rate of persistent postoperative opioid use in opioid-naive patients was 5.7% (95% CI: 4.2-7.2%). Risk factors included female sex (OR 1.18; 95% CI: 1.09-1.29), smoking (OR 1.34; 95% CI: 1.06-1.69), alcohol use (OR 1.43; 95% CI: 1.17-1.76), congestive cardiac failure (OR 1.17; 95% CI: 1.08-1.27), diabetes mellitus (OR 1.21; 95% CI: 1.07-1.37), chronic lung disease (OR 1.42; 95% CI: 1.16-1.75), chronic kidney disease (OR 1.35; 95% CI: 1.08-1.68), and length of hospital stay (per day) (OR 1.03; 95% CI: 1.02-1.04). CONCLUSIONS: Persistent postoperative opioid use after cardiac surgery affects at least one in 20 patients. The identification of risk factors, such as female sex, smoking, alcohol use, congestive cardiac failure, diabetes mellitus, chronic lung disease, chronic kidney disease, and length of hospital stay, should help target interventions aimed at decreasing its prevalence.

The prognostic significance of postoperative hyperbilirubinemia in cardiac surgery: systematic review and meta-analysis.

BACKGROUND: Hyperbilirubinemia following cardiac surgery is a common phenomenon and is of emerging interest in prognostic factor research. This systematic review and meta-analysis evaluated the association between post-operative hyperbilirubinemia (PH) and mortality and morbidity in cardiac surgery patients. METHODS: Ovid Medline and Ovid Embase were searched from inception to July 2020 for studies evaluating the prognostic significance of PH following cardiac surgery. Maximally adjusted odds ratios (OR) with associated confidence intervals were obtained from each study and pooled using random effects inverse variance modelling to assess in-hospital mortality. Standardised mean differences were pooled to assess Intensive Care Unit (ICU) and hospital length of stay (LOS). Qualitative analysis was performed to assess ventilation requirements and long-term mortality. Meta-regression was used to assess inter- and intra-study heterogeneity. RESULTS: 3251 studies satisfied the selection criteria, from which 12 studies incorporating 3876 participants were included. PH significantly predicted in-hospital mortality with a pooled OR of 7.29 (95% CI 3.53, 15.09). Multiple pre-defined covariates contributed to the prognostic significance of PH, however only aortic cross-clamp time (p < 0.0001) and number of transfusions (p = 0.0001) were significant effect modifiers. PH significantly predicted both ICU LOS (Mean difference 1.32 [95% CI 0.04-2.6]) and hospital LOS (Mean difference 1.79 [95% CI 0.36-3.21]). Qualitative analysis suggested PH is associated with increased post-operative ventilation requirements and reduced long-term survival rates. CONCLUSIONS: Hyperbilirubinemia is a cost-effective, widely available prognostic marker of adverse outcomes following cardiac surgery, albeit with residual sources of heterogeneity.

Warm humidified CO2 insufflation improves pericardial integrity for cardiac surgery: a randomized control study.

BACKGROUND: Flooding the surgical field with dry cold CO2 during open-chamber cardiac surgery has been used to mitigate air entrainment into the systemic circulation. However, exposing epithelial surfaces to cold, dry gas causes tissue desiccation. This randomized controlled study was designed to investigate whether the use of humidified warm CO2 insufflation into the cardiac cavity could reduce pericardial tissue damage and the incidence of micro-emboli when compared to dry cold CO2 insufflation. METHODS: Forty adult patients requiring elective open-chamber cardiac surgery were randomized to have either dry cold CO2 insufflation via a standard catheter or humidified warm CO2 insufflation via the HumiGard device (Fisher & Paykel Healthcare, Panmure, Auckland, New Zealand). The primary endpoint was biopsied pericardial tissue damage, assessed using electron microscopy. We assessed the percentage of microvilli and mesothelial damage, using a damage severity score (DSS) system. We compared the proportion of patients who had less damage, defined as DSS<2. Secondary endpoints included the severity of micro-emboli, by visual assessment of bubble load on transesophageal echocardiogram; lowest near infrared spectroscopy; total de-airing time; highest cardio-pulmonary bypass sweep speed; hospital length of stay and complications. RESULTS: A higher proportion of patients in the humidified warm CO2 group displayed conserved microvilli (47% vs. 11%, P=0.03) and preserved mesothelium (42% vs. 5%, P=0.02) compared to the control group. There were no differences in the secondary outcomes. CONCLUSIONS: Humidified warm CO2 insufflation significantly reduced pericardial epithelial damage when compared to dry cold CO2 insufflation in open-chamber cardiac surgery. Further studies are warranted to investigate its potential clinical benefits.

Perioperative Neutrophil-Lymphocyte Ratio Predicts Mortality After Cardiac Surgery: Systematic Review and Meta-Analysis.

OBJECTIVES: Neutrophil-lymphocyte ratio (NLR) is an inflammatory biomarker that has been evaluated across a variety of surgical disciplines and is widely predictive of poor postoperative outcome, but its value in cardiac surgery is unclear. The authors did this systematic review and meta-analysis to determine the impact of elevated perioperative NLR on survival after cardiac surgery. DESIGN: Systematic review and meta-analysis of study-level data. SETTING: Multiple hospitals involved in an international pool of studies. PARTICIPANTS: Adults undergoing cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The authors searched multiple databases from inception until November 2020. They generated summary hazard ratios (HR) and odds ratios (OR) for the association of elevated preoperative NLR with long-term and short-term mortality following cardiac surgery. They separately reported on elevated postoperative NLR. Between-study heterogeneity was explored using metaregression. The authors included 12 studies involving 13,262 patients undergoing cardiac surgery. Elevated preoperative NLR was associated with worse long-term (>30 days) (hazard ratio [HR] 1.56; 95% CI [confidence interval], 1.18-2.06; 8 studies) and short-term (<30 days) mortality (OR 3.18; 95% CI, 1.90-5.30; 7 studies). One study reported the association of elevated postoperative NLR with long-term mortality (HR 8.58; 95% CI, 2.55-28.85). There was considerable between-study heterogeneity for the analysis of long-term mortality (I2 statistic 94.39%), which mostly was explained by study-level variables, such as the number of variables adjusted for by included studies and how many of these significantly increased the risk of long-term mortality, high risk of bias, and number of study centers, as well as participant level factors, such as average participant age and hypertension prevalence. CONCLUSIONS: Perioperative NLR is an independent predictor of short-term and long-term postoperative mortality following cardiac surgery. Further research is required to determine which patient-level factors modify the prognostic value of NLR and to evaluate its role in routine clinical practice.

Machine Learning Outperforms Existing Clinical Scoring Tools in the Prediction of Postoperative Atrial Fibrillation During Intensive Care Unit Admission After Cardiac Surgery.

OBJECTIVE(S): Using the Medical Information Mart for Intensive Care III (MIMIC-III) database, we compared the performance of machine learning (ML) to the to the established gold standard scoring tool (POAF Score) in predicting postoperative atrial fibrillation (POAF) during intensive care unit (ICU) admission after cardiac surgery. METHODS: Random forest classifier (RF), decision tree classifier (DT), logistic regression (LR), K neighbours classifier (KNN), support vector machine (SVM), and gradient boosted machine (GBM) were compared to the POAF Score. Cross-validation was used to assess the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of ML models. POAF Score performance confidence intervals were generated using 1,000 bootstraps. Risk profiles for GBM were generated using Shapley additive values. RESULTS: A total of 6,349 ICU admissions encompassing 6,040 patients were included. POAF occurred in 1,364 of the 6,349 admissions (21.5%). For predicting POAF during ICU admission after cardiac surgery, GBM, LR, RF, KNN, SVM and DT achieved an AUC of 0.74 (0.71-0.77), 0.73 (0.71-0.75), 0.72 (0.69-0.75), 0.68 (0.67-0.69), 0.67 (0.66-0.68) and 0.59 (0.55-0.63) respectively. The POAF Score AUC was 0.63 (0.62-0.64). Shapley additive values analysis of GBM generated patient level explanations for each prediction. CONCLUSION: Machine learning models based on readily available preoperative data can outperform clinical scoring tools for predicting POAF during ICU admission after cardiac surgery. Explanatory models are shown to have potential in personalising POAF risk profiles for patients by illustrating probabilistic input variable contributions. Future research is required to evaluate the clinical utility and safety of implementing ML-driven tools for POAF prediction.

The Prognostic Value of Elevated Perioperative Neutrophil-Lymphocyte Ratio in Predicting Postoperative Atrial Fibrillation After Cardiac Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: The neutrophil-lymphocyte ratio (NLR) is an emerging inflammatory perioperative biomarker which has been studied to predict the incidence of postoperative atrial fibrillation (POAF) after cardiac surgery. This systematic review and meta-analysis aimed to evaluate the prognostic accuracy of elevated perioperative NLR in predicting POAF after cardiac surgery. METHODS: Multiple databases were searched from inception to May 2019 for prognostic studies on perioperative NLR and POAF following cardiac surgery. Maximally adjusted odds ratios (OR) with associated confidence intervals were obtained from each included study and pooled using random effects inverse variance modelling for preoperative NLR measurements, while standardised mean differences were pooled for postoperative NLR values. The significance of inter- and intra-study heterogeneity was explored using meta-regression. RESULTS: 1,799 unique studies satisfied selection criteria, from which 12 studies incorporating 9,262 participants were included. Elevated preoperative NLR significantly predicted POAF, with a pooled OR of 1.42 (95% CI 1.16-1.72). Multiple predefined covariates contributed to inter-study heterogeneity; however, only prevalence of hypertension (p=0.0055), history of congestive cardiac failure (p=0.0282) and average ejection fraction (p=0.0359) were significant effect modifiers. Elevated postoperative NLR was not a significant predictor of POAF (standardised mean difference 1.60 [95% CI -0.56-3.77] between POAF+ and POAF- groups). CONCLUSIONS: Elevated preoperative NLR is a promising prognostic biomarker for POAF, but residual sources of heterogeneity remain. Larger scale validation studies are required to justify the integration of preoperative NLR testing into routine clinical practice.

Effective nonanatomical endoscopy training produces clinical airway endoscopy proficiency.

We studied the effectiveness of two nonanatomical endoscopic dexterity training models: "Choose the Hole" and Dexter. Effectiveness was assessed in terms of time spent training, subjective rating, performance on an anatomical manikin, and clinical performance on fellow participants who acted as awake subjects. Forty-three anesthesia specialists, trainees, and technicians volunteered. Performances were videotaped, timed, and scored with a Global Rating Scale (GRS) from 1 (very poor) to 5 (clearly superior). The Dexter group spent more time training than the Choose the Hole group (median time [range], 152 min [70-510 min] versus 75 min [17-281 min]; P < 0.01). Subjective ratings were better in the Dexter group. In clinical bronchoscopy, the Dexter group was faster (30.7 s [17.1-43.5 s] versus 36.6 s [22.8-105.1 s]; P = 0.02) and had higher GRS scores (mean [sd]: 3.0 [0.4] versus 2.6 [0.6]; P = 0.04), indicating superior performance. Clinical and manikin performance (GRS scores) were significantly correlated (rho = 0.62; P = 0.0001). Benchmark levels of clinical bronchoscopic performance can be anticipated from bench model performance without a clinical learning curve. Dexter is a more effective model for learning endoscopic dexterity than the Choose the Hole model. Airway topicalization with lidocaine in a dose range consistent with published series (490-980 mg or 7.14-14.77 mg/kg) resulted in a frequent incidence of side effects. No major adverse events occurred.