Elective Adult Cardiac Surgery Research Articles

Effectiveness of Minimal Acute Normovolemic Hemodilution in Elective Adult Cardiac Surgery

Effectiveness of Minimal Acute Normovolemic Hemodilution in Elective Adult Cardiac Surgery

Exploring the rate and reasons for same-day cancellation of cardiac surgery after implementing joint commission international standards: a retrospective cross-sectional study

BackgroundSame-day cancellation of cardiac surgery significantly impacts operating room management efficiency, which can be mitigated by taking preventive measures. This study aimed to explore the same-day cancellation rate of elective adult cardiac surgery, as well as the reasons for those cancellations. A retrospective cross-sectional study reviewed the records of 581 scheduled elective adult cardiac surgical cases at a single cardiac center from June 2017 to May 2018. The same-day cancellation reasons were grouped into four broad categories: nonclinical cancellations, clinical cancellations, patient-related cancellations, and 'other reason' cancellations. A case was considered canceled when it was not performed on the same day as the planned surgery.ResultsA total of 581 elective adult cardiac surgeries were scheduled during the study period, and 56 (9.63%) of these were canceled. The highest cancellation rate was due to nonclinical cancellations, with 39% of scheduled cases, followed by clinical cancellations, with a 34% cancellation rate. Patient-related cancellations accounted for 23% of cancellations, while the lowest rate was due to ‘other reasons,’ which accounted for 4% of total cancellations. The most common reason for nonclinical cancellations was the inclusion of emergency cases (n = 8; 14%). The most common reason for clinical cancellations was changes in the patient’s medical condition (n = 8, 14%). The common reason for patient-related cancellations was the refusal of surgery (n = 9; 16%). The lowest rate was for menstruating female patients (n = 2; 4%).ConclusionsThe same-day cancellation rate was 9.36%, and most of the cancellation reasons could be mitigated by implementing preventive strategies to improve the efficiency of the operating room. Preoperative preparation clinics and paying particular attention to female patients scheduled for surgery might reduce the rate of elective cardiac surgery cancellation.

Center-Level Variation in Failure to Rescue After Elective Adult Cardiac Surgery

BackgroundThere has been increasing emphasis on evaluation of failure to rescue (FTR) after major inpatient operations. The present study characterized center-level variation in FTR within a national cohort of patients undergoing elective cardiac operations. MethodsAll adults undergoing elective coronary artery bypass grafting and/or valve operations were identified in the 2016-2019 Nationwide Readmissions Database. FTR was defined as in-hospital death after prolonged mechanical ventilation, stroke, reoperation, acute kidney injury requiring dialysis, sepsis, cardiac arrest or pulmonary embolism. Multi-level, mixed-effects regressions were used to model mortality, complications, and FTR. Centers with high hospital-specific rates of FTR (≥95th percentile) were identified and compared to others. ResultsOf an estimated 454,506 patients included for analysis, 32,537 (7.2%) developed at least 1 complication, and 7669 (1.7%) died before discharge. Overall, 5370 (16.5%) patients experienced FTR. Compared with those who developed ≥1 complication but survived to discharge, FTR patients were significantly older, more commonly female, and had a greater burden of comorbidities as measured by the Elixhauser Comorbidity Index. Risk-adjusted, hospital-specific rates of mortality and FTR were moderately correlated (r = 0.64), mortality and complications were weakly associated (r = 0.16), and complications and FTR exhibited a very weak relationship (r = –0.02). Relative to others, centers with high rates of FTR had lower annual cardiac surgical volume (median 61 [interquartile range 33-133] vs 80 [interquartile range 43-149] cases/y, P = .019). ConclusionsThe present findings affirm prior work demonstrating a close link between variation in FTR and mortality, but not complications. Further study is necessary to delineate modifiable care pathways that mitigate FTR.

24th hour vasoactive inotrope score is associated with poor outcome in adult cardiac surgery.

The aim of this study was to investigate the efficacy of vasoactive inotrope score at the 24th postoperative hour for mortality and morbidity in elective adult cardiac surgery. Consecutive patients who underwent elective adult coronary artery bypass and valve surgery in a single tertiary center for cardiac surgery between December 2021 and March 2022 were prospectively included. The vasoactive inotrope score was calculated with the dosage of inotropes that were continuing at the 24th postoperative hour. Poor outcome was defined as any event of perioperative mortality or morbidity. The study included 287 patients, of whom 69 (24.0%) were on inotropes at the 24th postoperative hour. The vasoactive inotrope score was higher (21.6±22.5 vs. 0.94±2.7, p=0.001) in patients with poor outcome. One unit increase in the vasoactive inotrope score had an odds ratio of 1.24 (95% confidence interval: 1.14-1.35) for poor outcome. The receiver operating characteristic curve of vasoactive inotrope score for poor outcome had an area under the curve of 0.857. Vasoactive inotrope score at the 24th hour can be a very valuable parameter for risk calculation in the early postoperative period.

Morbidity and Mortality Associated With Blood Transfusions in Elective Adult Cardiac Surgery

Perioperative transfusion thresholds have garnered increasing scrutiny as restrictive strategies have been shown to be noninferior. The study authors used data from a statewide academic collaborative to test the association between transfusion and 30-day mortality. All adult patients undergoing coronary artery bypass grafting (CABG) and/or valve surgeries between 2013 and 2019 in the authors' Academic Cardiac Surgery Consortium were examined. The relationship between the number of overall packed red blood cell (pRBC) and coagulation product (CP) (fresh frozen plasma, cryoprecipitate, platelets) transfusions on 30-daymortality was evaluated. Multivariate regression was used to evaluate predictors of transfusion and study endpoints. Machine learning (ML) models also were developed to predict 30-day mortality and rank transfusion-related features by relative importance. At an Academic Cardiac Surgery Consortium of 5 institutions. Patients ≥18 years old undergoing CABG and/or valve surgeries. Of the 7,762 patients (median hematocrit [HCT] 39%, IQR 35%-43%) who were included in the final study cohort, >40% were transfused at least 1 unit of pRBC or CP. In adjusted analyses, higher preoperative HCT was associated with reduced odds of mortality (adjusted odds ratio [aOR] 0.95, 95% CI 0.92-0.98), renal failure (aOR 0.95, 95% CI 0.92-0.98), and prolonged mechanical ventilation (aOR 0.97, 95% CI 0.95-0.99). In contrast, perioperative transfusions were associated with increased 30-day mortality after adjustment for preoperative HCT and other baseline features. The ML models were able to predict 30-day mortality with an area under the curve of 0.814-to-0.850, with perioperative transfusions displaying the highest feature importance. The present analysis found increasing HCT to be associated with a lower incidence of mortality. The study authors also found a direct dose-response association between transfusions and all study endpoints examined.

A multi-centre prospective cohort study of patients on the elective waiting list for cardiac surgery during the COVID-19 pandemic

During the worldwide COVID-19 pandemic, elective cardiac surgery was suspended to provide ICU beds for COVID-19 patients and those requiring urgent cardiac surgery. The aim of this study is to assess the effect of the pandemic on outcomes of patients awaiting elective cardiac surgery. A multi-centre prospective cohort study. The elective adult cardiac surgery waiting list as of 1 March 2020 across seven UK cardiac surgical centres. Patients on the elective adult cardiac surgery waiting list as of 1 March 2020 across seven UK cardiac surgical centres. Primary outcome was surgery, percutaneous therapy or death at one year. Data were collected prospectively on patients on the elective adult cardiac surgery waiting list as of 1 March 2020 across seven UK cardiac surgical centres. Primary outcome was surgery, percutaneous therapy or death at one year. Demographic data and outcomes were obtained from local electronic records, anonymised and submitted securely to the lead centre for analysis. On 1 March 2020, there were 1099 patients on the elective waiting list for cardiac surgery. On 1 March 2021, 83% (n = 916) had met a primary outcome. Of these, 840 (92%) had surgery after a median of 195 (118-262) days on waiting list, 34 (3%) declined an offer of surgery, 23 (3%) had percutaneous intervention, 12 (1%) died, 7 (0.6%) were removed from the waiting list. The remainder of patients, 183 (17%) remained on the elective waiting list. This study has shown, for the first time, significant delays to treatment of patients awaiting elective cardiac surgery. Although there was a low risk of mortality or urgent intervention, important unmeasured adverse outcomes such as quality of life or increased perioperative risk may be associated with prolonged waiting times.

Perioperative Continuous Noninvasive Cardiac Output Monitoring in Cardiac Surgery Patients by a Novel Capnodynamic Method

To test the clinical performance of a novel continuous noninvasive cardiac output (CO) monitoring based on expired carbon dioxide kinetics in cardiac surgery patients. A prospective feasibility pragmatic clinical study. A single-center, large community hospital. Thirty-two patients undergoing cardiac surgery were studied during the intraoperative (before cardiopulmonary bypass) and postoperative (in the intensive care unit before extubation) periods. CO was measured simultaneously by the continuous capnodynamic method and by transpulmonary thermodilution during changes in the patient's hemodynamic and/or respiratory conditions. The current recommended comparative statistics for CO measurement methods were analyzed, including bias, precision, and percentage error obtained from Bland-Altman analysis, and concordance between methods obtained from the four-quadrant plot analysis to evaluate the trending ability. Bias ± limits of agreement and percentage error were -0.6 (-1.9 to +0.8; 95% CI of 3.73-5.25) L/min and 31% (n=147 measurements) for the intraoperative period, -0.8 (-2.4 to +0.9; 95% CI of 3.03-5.21) L/min and 41% (n=66) for the postoperative period, and -0.6 (-2.1 to +0.8; 95% CI of 3.74-5.00) L/min and 34% (n=213) for the pooled data. The trending analysis obtained a concordance of 82% (n=65) for the intraoperative and 71% (n=24) for the early postoperative periods. Aggregation of both data sets gave a concordance of 79% (n=89). The continuous capnodynamic method was reliable and in good agreement with the reference method, and had an accuracy and trending ability good enough tomake it a possible future alternative for hemodynamic monitoring in the studied population of elective adult cardiac surgery patients.

Predictors of aortic clamp time duration and intensive care unit length of stay in elective adult cardiac surgery

BackgroundAortic cross-clamp utilized during cardiac surgery facilitates motionless and bloodless surgical field. However, the duration of clamp time has an inverse effect on early post-operative recovery period. In this study, we sought to examine the predictors of aortic clamp duration and intensive care unit length of stay.ResultsSix hundred and nine adult patients presented for elective cardiac surgery between December 2019 and December 2020 were enrolled. The age of patients ranged from 18 to 82 years (mean 55.62 years, SD ± 12.3 years). Male/female ratio is 4.6:1. Most patients (87.2%) were planned for coronary artery bypass grafting (CABG) and 78 patients (12.8%) for single heart valve procedure. Operative time (OT) ranged from 120 to 402 min and averaged 259.4 min (SD ± 45.9 min). ACC time ranged from 15 to 159 min and averaged 50.56 min (SD ± 19.4 min). Factors associated with significantly longer ACCT were: smoking (OR = 1.89 (95% CI 1.3–2.74), p value = 0.01), respiratory disease (OR = 0.48 (95% CI 0.24–0.96), p value = 0.039), obesity (OR = 1.76 (95% CI 1.18–2.63), p value = 0.005) and AVR (OR = 2.11 (95% CI 1.17–3.83), p value = 0.013). Low cardiac output syndrome (LCOS) was observed in 19.2% of patients. Longer than average ACCT was associated with increased use of inotropes (p value < 0.001), intra-aortic balloon pump (p value < 0.001) and first 24 h post-operative blood loss (p value < 0.001). The average intensive care unit length of stay (ICULOS) was 1.64 days (SD ± 1.1 days). Patients' ACCT converged positively and significantly on ICULOS (Beta coefficient = 1.013 (95% CI 1.01–1.015), p value < 0.001).ConclusionAortic cross-clamping is a crucial method in cardiac surgery to achieve motionless field; however, prolongation of this method had an incremental risks for the development of low cardiac output syndrome, increased first 24 h post-operative blood loss and longer stay in the intensive care unit.

Factors Associated With High Resource Use in Elective Adult Cardiac Surgery From 2005 to 2016

BackgroundLack of consensus remains about factors that may be associated with high resource use (HRU) in adult cardiac surgical patients. This study aimed to identify patient-related, hospital, and perioperative characteristics associated with HRU admissions involving elective cardiac operations. MethodsData from the National Inpatient Sample was used to identify patients who underwent coronary artery bypass graft, valve replacement, and valve repair operations between 2005 and 2016. Admissions with HRU were defined as those in the highest decile for total hospital costs. Multivariable regressions were used to identify factors associated with HRU. ResultsAn estimated 1,750,253 hospitalizations coded for elective cardiac operations. The median hospitalization cost was $34,700 (interquartile range, $26,800– to $47,100), with the HRU (N = 175,025) cutoff at $66,029. Although HRU patients comprised 10% of admissions, they accounted for 25% of cumulative costs. On multivariable regression, patient-related characteristics predictive of HRU included female sex, older age, higher comorbidity burden, non-White race, and highest income quartile. Hospital factors associated with HRU were low-volume hospitals for both coronary artery bypass graft and valvular operations. Among postoperative outcomes, mortality, infectious complications, extracorporeal membrane oxygenation use, and hospitalization for more than 8 days were associated with greater odds of HRU. ConclusionsIn this nationwide study of elective cardiac surgical patients, several important patient-related and hospital factors, including patients’ race, comorbidities, postoperative infectious complications, and low hospital operative volume were identified as predictors of HRU. These highly predictive factors may be used for benchmarking purposes and improvement in surgical planning.

Preoperative pulmonary function in all comers for cardiac surgery predicts mortality†.

Although reduced lung function and chronic obstructive pulmonary disease (COPD) is associated with higher risk of death following cardiac surgery, preoperative spirometry is not performed routinely. The aim of this study was to investigate the relationship between preoperative lung function and postoperative complications in all comers for cardiac surgery irrespective of smoking or COPD history. Preoperative spirometry was performed in elective adult cardiac surgery patients. Airflow obstruction was defined as the ratio of forced expiratory volume in 1 s (FEV1)/forced vital capacity ratio below the lower limit of normal (LLN) and reduced forced ventilatory capacity defined as FEV1 <LLN. A history of COPD was reported by 132 (19%) patients; however, only 74 (56%) had spirometry-verified airflow obstruction. Conversely, 64 (12%) of the 551 patients not reporting a history of COPD had spirometry-verified airflow obstruction. The probability of death was significantly higher in patients with airflow obstruction (8.8% vs 4.5%, P = 0.04) and in patients with a FEV1 <LLN (8.7% vs 3.7%, P = 0.007). In the multivariate analysis were age [hazard ratio (HR) 1.6, 95% confidence interval (CI) 1.0-2.5; P = 0.04], prolonged cardiopulmonary bypass time (HR 1.2, 95% CI 1.02-1.3; P = 0.03), reduced kidney function (HR 2.5, 95% CI 1.2-5.6; P = 0.02) and FEV1 <LLN (HR 2.4, 95% CI 1.1-5.2; P = 0.03) all independently associated with an increased risk of death. Preoperative spirometry reclassified 18% of the patients. A reduced FEV1 independently doubled the risk of death. Inclusion of preoperative spirometry in routine screening of cardiac surgical patients may improve risk prediction and identify high-risk patients. NCT01614951 (ClinicalTrials.gov).

Preoperative thromboelastometry for the prediction of increased chest tube output in cardiac surgery: A retrospective study.

Bleeding following cardiac surgery is a serious event with potentially life-threatening consequences. Preoperative recognition of coagulation abnormalities and detection of cardiopulmonary bypass (CPB) related coagulopathy could aid in the start of preventive treatment strategies that minimize perioperative blood loss. Most algorithms that analyze thromboelastometry coagulation tests in elective cardiac surgery do not include test results performed before surgery. We evaluated preoperative rotational thromboelastometry test results for their ability to predict blood loss during and after cardiac surgery.A total of 114 adult patients undergoing cardiac surgery with CPB were included in this retrospective analysis. Each patient had thromboelastometry tests done twice: preoperatively, before the induction of anesthesia and postoperatively, 10 minutes after heparin reversal with protamine after decannulation.Patients were placed into 1 of 2 groups depending on whether preoperative thromboelastometry parameters deviated from reference ranges: Group 1 [N = 29; extrinsically activated test (EXTEM) or INTEM results out of normal range] or Group 2 (N = 85; EXTEM and INTEM results within the normal range). We observed that the total amount of chest tube output was significantly greater in Group 1 than in Group 2 (700 mL vs 570 mL, P = .03). At the same time, the preoperative values of standard coagulation tests such as platelet count, aPTT, and INR did not indicate any abnormalities of coagulation.Preoperative coagulation abnormalities diagnosed with thromboelastometry can predict increased chest tube output in the early postoperative period in elective adult cardiac surgery. Monitoring of the coagulation system with thromboelastometry allows rapid diagnosis of coagulation abnormalities even before the start of the surgery. These abnormalities could not always be detected with routine coagulation tests.

Facteurs prédictifs de long séjour en réanimation après chirurgie cardiaque programmée de l’adulte : étude rétrospective monocentrique sur 5 ans et demi

AimThe aim of our study was to identify predictors for prolonged ICU stay following elective adult cardiac surgery under cardiopulmonary bypass. Patients and methodsA retrospective study was conducted during 5 years and a half period. Were included, patients age≥18 years old, underwent elective cardiac surgery under cardiopulmonary bypass. Patients who died within 48hours of surgery were excluded. Prolonged ICU stay was defined as stay in the ICU for 48hours or more. ResultsDuring the review period, 610 patients were included. One hundred and sixty-four patients have required a prolonged ICU stay (26.9 %). In multivariate analysis, 5 predictors were identified: ejection fraction<30 % (OR 19.991, IC 95 % [1.382–289.1], P=0.028], pulmonary hypertension (OR 2.293, IC 95 % [1.058–4.973], P=0.036), prolonged ventilation (≥12hours) (OR 4.026, IC 95 % [2.407–6.733], P<0.001). Number of blood units transfused (OR 1.568, IC 95 % [1.073–2.291], and postoperative acute renal failure (OR 2.620, IC 95 % [1.026–6.690], P=0.044]. Prolonged ICU stay is significantly associated with prolonged hospital stay (17 days vs 13 days ; P<0.001) and higher in hospital mortality (22 % vs. 3 %, P<0.001). ConclusionThe identification of these patients at risk of prolonged ICU stay is crucial. It will aid to plan prophylactic measures to optimize their support.

Reducing Mediastinitis after Sternotomy with Combined Chlorhexidine-Isopropyl Alcohol Skin Disinfection: Analysis of 3,000 Patients.

Reducing surgical site infections (SSI) following median sternotomy remains a challenge for cardiac surgeons. Standard prophylaxis of SSI at our institution includes pre-operative skin disinfection with isopropyl alcohol (IPA). The addition of chlorhexidine gluconate (CHG) has the theoretical advantage of longer antimicrobial activity (>48h), compared with 2 h for IPA alone. This prospective registry study was conducted to evaluate the effect of combined CHG-IPA (ChloraPrep®) skin antiseptic on the incidence of sternal surgical incision infections after cardiac surgical procedures via median sternotomy. Between September 2011 and November 2013, 3,942 consecutive patients underwent cardiac surgery with median sternotomy at our institution. Among them, 2,985 patients met inclusion criteria and were enrolled in the study. The complete cohort was prospectively divided into two registries. In registry 1 (1,523 patients), CHG-IPA was used to disinfect skin at the thoracic operative site prior to incision. In registry 2 (1,462 patients), single IPA disinfection was used. The primary endpoint was the incidence of post-sternotomy mediastinitis within 30 d of surgery. Secondary endpoints were SSI of any other kind, 30-d survival, and hospital length of stay. Both registries were well matched in baseline characteristics and main risk factors. Post-operative data analysis revealed reduction in the rate of post-sternotomy mediastinitis in registry 1 (29 patients, 1.9%) versus registry 2 (62 patients, 4.2%), p = 0.0002. No relevant difference in incidence of other surgical site infections, length of hospital stay, and 30-d mortality was found. Skin disinfection with combined chlorhexidine-isopropyl alcohol reduced the incidence of mediastinitis in elective adult cardiac surgery with median sternotomy but did not affect other types of surgical site infections.

Point-of-Care Hemoglobin/Hematocrit Testing: Comparison of Methodology and Technology

Point-of-care (POC) testing allows rapid assessment of hemoglobin (Hgb) and hematocrit (Hct) values. This study compared 3 POC testing devices--the Radical-7 pulse oximeter (Radical-7, Neuchȃtel, Switzerland), the i-STAT (Abbott Point of Care, Princeton, NJ), and the GEM 4000 (Instrumentation Laboratory, Bedford, MA)--to the hospital reference device, the UniCel DxH 800 (Beckman Coulter, Brea, CA) in cardiac surgery patients. Prospective study. Tertiary care cardiovascular center. Twenty-four consecutive elective adult cardiac surgery patients. Hgb and Hct values were measured using 3 POC devices (the Radical-7, i-STAT, and GEM 4000) and a reference laboratory device (UniCel DxH 800). Data were collected simultaneously before surgery, after heparin administration, after heparin reversal with protamine, and after sternal closure. Data were analyzed using bias analyses. POC testing data were compared with that of the reference laboratory device. Hgb levels ranged from 6.8 to 15.1 g/dL, and Hct levels ranged from 20.1% to 43.8%. The overall mean bias was lowest with the i-STAT (Hct, 0.22%; Hgb 0.05 g/dL) compared with the GEM 4000 (Hct, 2.15%; Hgb, 0.63 g/dL) and the Radical-7 (Hgb 1.16 g/dL). The range of data for the i-STAT and Radical-7 was larger than that with the GEM 4000, and the pattern or slopes changed significantly with the i-STAT and Radical-7, whereas that of the GEM 4000 remained relatively stable. The GEM 4000 demonstrated a consistent overestimation of laboratory data, which tended to improve after bypass and at lower Hct/Hgb levels. The i-STAT bias changed from overestimation to underestimation, the latter in the post-cardiopulmonary bypass period and at lower Hct/Hgb levels. By contrast, the Radical-7 biases increased during the surgical procedure and in the lower ranges of Hgb. Important clinical differences and limitations were found among the 3 POC testing devices that should caution clinicians from relying on these data as sole determinants of when or when not to perform transfusion in patients. Even though a low bias might support the use of POC data, further analysis of the bias plots demonstrates pattern changes during the surgical procedure and across the range of Hct/Hgb data.

Determinants of the relationship between cost and survival time after elective adult cardiac surgery.

Cardiac surgery is increasingly performed on elderly patients with multiple comorbid conditions, but the determinants of the relationship between cost and survival time after cardiac surgery for patients with a serious cardiac condition remain uncertain. Using the long-term outcome data of a cohort study on adult cardiac surgical patients, the relationship between cost and survival time after cardiac surgery from a hospital service perspective was determined. The total cost for each patient was estimated by the costs of the surgical procedures, intra-aortic balloon pump utilisation, operating theatre utilisation, blood products, intensive care unit stay and cumulative hospital stay up to a median follow-up time of 30 months. Of the 2131 patients considered in this study, a total cost >A$100,000 per life-year after cardiac surgery was observed only in 171 patients (8.0%, 95% confidence interval 6.9 to 9.3%). Age, Charlson Comorbidity Index and EuroSCORE were all related to the cost per life-year after cardiac surgery, but EuroSCORE (odds ratio 1.26 per score increment, 95% confidence interval 1.18 to 1.35, P=0.001) was, by far, the most important determinant and explained 32% of the variability in cost per life-year after cardiac surgery. Patients with a high EuroSCORE were associated with a substantially longer length of intensive care unit stay and cumulative hospital stay, as well as a shorter survival time after cardiac surgery compared to patients with a lower EuroSCORE. Of all the subgroups of patients examined, only patients with a EuroSCORE >5 were consistently associated with a cost >A$100,000 per life-year (cost per life-year $183,148, 95% confidence interval 125, 394 to 240, 902).

Acute kidney injury after elective adult cardiac surgery

Acute kidney injury (AKI) is a significant complication following cardiac surgery associated with an increase in morbidity, hospital stay and mortality. Although the estimated incidence of AKI following cardiac surgery is 30%, few studies have identified the incidence of AKI following cardiac surgery as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) group [1]. We conducted a prospective observational study at our institution to identify the incidence and staging of AKI according to the KDIGO definition. We also aim to identify the factors that predispose adult patients to developing AKI post cardiac surgery.

Delays in extubation following elective adult cardiac surgery

Early extubation post coronary artery bypass grafting does not increase perioperative morbidity and reduces the length of stay (LOS) in the ICU and in hospital [1]. Use of low-dose opioid- based general anaesthesia and time-directed protocols for fast- track interventions does not increase mortality or postoperative complications in low-moderate-risk patients and has been found to have a reduced time to extubation and shortened ICU stay [2]. Our mean time to extubation is 6 hours, although patients are assessed to be safe to be weaned from mechanical ventilation at 2 hours following arrival in the ICU. This study aims to identify factors that delay extubation in patients undergoing routine cardiac surgery at our institution.

Differential Associations between Body Mass Index and Outcomes after Elective Adult Cardiac Surgery: A Linked Data Cohort Study

This study assessed the relationships between body mass index (BMI) and different outcomes after adult cardiac surgery by linking detailed preoperative comorbidity data with the long-term mortality and morbidity outcomes of 2131 consecutive patients who had elective cardiac surgery at a major cardiac surgical hospital in Western Australia. Patients with a high BMI had more comorbidities and were more likely to have had coronary artery bypass grafting than valve surgery. A total of 143 patients (6.7%) died during a median follow-up period of 30 months. The major causes of death were congestive heart failure (25.9%), myocardial infarction (14.7%), infection (23.8%) and cancer (13.9%). BMI had no association with long-term mortality, after adjusting for important confounders including the Charlson Comorbidity Index. BMI had a relatively linear relationship with the risk of new-onset atrial fibrillation (odds ratio 1.05 per point increment, 95% confidence interval 1.03 to 1.05) and venous thromboembolism (odds ratio 1.20, 95% confidence interval 1.14 to 1.26). BMI was the second most important predictor after age and accounted for 22% of the variability in the risk of atrial fibrillation. BMI had an inverse relationship with the risk of requiring allogeneic blood transfusion, postoperative intra-aortic balloon pump, or surgical re-exploration. In summary, BMI had differential associations with different short- and long-term outcomes after elective adult cardiac surgery. After adjusting for important confounders including the presence of cancers, we did not observe any 'obesity paradox' and patients with a high BMI were not associated with an increased probability of long-term survival.

Changes in myocardial lactate, pyruvate and lactate-pyruvate ratio during cardiopulmonary bypass for elective adult cardiac surgery: Early indicator of morbidity

Background:Myocardial lactate assays have been established as a standard method to compare various myocardial protection strategies. This study was designed to test whether coronary sinus (CS) lactates, pyruvate and lactate-pyruvate (LP) ratio correlates with myocardial dysfunction and predict postoperative outcomes.Materials and Methods:This prospective observational study was conducted on 40 adult patients undergoing elective cardiac surgery with the aid of cardiopulmonary bypass (CPB). CS blood sampling was done for estimation of myocardial lactate (ML), pyruvate (MP) and lactate-pyruvate ratio (MLPR) namely: pre-CPB (T1), after removal of aortic cross clamp (T2) and 30 minutes post-CPB (T3).Results:Baseline myocardial LPR strongly correlated with Troponin-I at T1 (σ: 0.6). Patients were sub grouped according to the median value of myocardial lactate (2.9) at baseline T1 into low myocardial lactate (LML) group, mean (2.39±0.4 mmol/l), n=19 and a high myocardial lactate (HML) group, mean (3.65±0.9 mmol/l), n = 21. A significant increase in PL, ML, MLPR and TropI occurred in both groups as compared to baseline. Patients in HML group had significant longer period of ICU stay. Patients with higher inotrope score had significantly higher ML (T2, T3). ML with a baseline value of 2.9 mmol/l had 70.83% sensitivity and 62.5% specificity (ROC area: 0.7109 Std error: 0.09) while myocardial pyruvate with a baseline value of 0.07 mmol/l has 79.17% sensitivity and 68.75% specificity (ROC area: 0.7852, Std error: 0.0765) for predicting inotrope requirement after CPB.Conclusion:CS lactate, pyruvate and LP ratio correlate with myocardial function and can predict postoperative outcome.

The effect of hemodilution during normothermic cardiac surgery on renal physiology and function: a review

Although the definitions of renal dysfunction vary, loss of renal function is a common complication following cardiac surgery using cardiopulmonary bypass (CPB). When postoperative dialysis is required, mortality is approximately 50%. CPB-accompanied hemodilution is a major contributing factor to renal damage as it notably reduces oxygen delivery by reducing the oxygen transport capacity of the blood as well as disturbing the microcirculation. To minimize hypoxemic damage during CPB, lowering of body temperature is applied to reduce the patient's metabolic rate. At present, however, temperature management during elective adult cardiac surgery is shifting from moderate hypothermia to normothermia. To determine whether the currently accepted levels of hemodilution during CPB can suffice the normothermic patient's high oxygen demand, we focused this study on renal physiology and postoperative renal function. Hemodilution reduces the capillary density through a diminished capillary viscosity, thereby, redistributing blood from the renal medulla to the renal cortex. As the physiology of the renal medulla makes it a hypoxic environment, this part of the kidney appears to be especially at risk for hypoxic damage caused by a hemodilution-induced lowered oxygen transport and oxygen delivery. In addition, hemodilution is also likely to disturb the hormonal systems regulating renal blood distribution. Clinical studies, mostly of retrospective or observational nature, show that perioperative nadir hematocrit levels lower than approximately 24% are associated with an increased risk to develop postoperative renal failure. A better comprehension of the cause-and-effect relation between low perioperative hematocrits and loss of postoperative renal function may enable more effective renal protective strategies.