Effects of intraoperative inspired oxygen fraction (FiO2 0.3 vs 0.8) on patients undergoing off-pump coronary artery bypass grafting: the CARROT multicenter, cluster-randomized trial.

BACKGROUND: To maintain adequate oxygenation is of utmost importance in intraoperative care. However, clinical evidence supporting specific oxygen levels in distinct surgical settings is lacking. This study aimed to compare the effects of 30% and 80% oxygen in off-pump coronary artery bypass grafting (OPCAB). METHODS: This multicenter trial was conducted in three tertiary hospitals from August 2019 to August 2021. Patients undergoing OPCAB were cluster-randomized to receive either 30% or 80% oxygen intraoperatively, based on the month when the surgery was performed. The primary endpoint was the length of hospital stay. Intraoperative hemodynamic data were also compared. RESULTS: A total of 414 patients were cluster-randomized. Length of hospital stay was not different in the 30% oxygen group compared to the 80% oxygen group (median, 7.0 days vs 7.0 days; the sub-distribution hazard ratio, 0.98; 95% confidence interval [CI] 0.83-1.16; P = 0.808). The incidence of postoperative acute kidney injury was significantly higher in the 30% oxygen group than in the 80% oxygen group (30.7% vs 19.4%; odds ratio, 1.94; 95% CI 1.18-3.17; P = 0.036). Intraoperative time-weighted average mixed venous oxygen saturation was significantly higher in the 80% oxygen group (74% vs 64%; P < 0.001). The 80% oxygen group also had a significantly greater intraoperative time-weighted average cerebral regional oxygen saturation than the 30% oxygen group (56% vs 52%; P = 0.002). CONCLUSIONS: In patients undergoing OPCAB, intraoperative administration of 80% oxygen did not decrease the length of hospital stay, compared to 30% oxygen, but may reduce postoperative acute kidney injury. Moreover, compared to 30% oxygen, intraoperative use of 80% oxygen improved oxygen delivery in patients undergoing OPCAB. Trial registration ClinicalTrials.gov (NCT03945565; April 8, 2019).

An ensemble machine learning approach to predict postoperative mortality in older patients undergoing emergency surgery.

BACKGROUND: Prediction of preoperative frailty risk in the emergency setting is a challenging issue because preoperative evaluation cannot be done sufficiently. In a previous study, the preoperative frailty risk prediction model used only diagnostic and operation codes for emergency surgery and found poor predictive performance. This study developed a preoperative frailty prediction model using machine learning techniques that can be used in various clinical settings with improved predictive performance. METHODS: This is a national cohort study including 22,448 patients who were older than 75 years and visited the hospital for emergency surgery from the cohort of older patients among the retrieved sample from the Korean National Health Insurance Service. The diagnostic and operation codes were one-hot encoded and entered into the predictive model using the extreme gradient boosting (XGBoost) as a machine learning technique. The predictive performance of the model for postoperative 90-day mortality was compared with those of previous frailty evaluation tools such as Operation Frailty Risk Score (OFRS) and Hospital Frailty Risk Score (HFRS) using the receiver operating characteristic curve analysis. RESULTS: The predictive performance of the XGBoost, OFRS, and HFRS for postoperative 90-day mortality was 0.840, 0.607, and 0.588 on a c-statistics basis, respectively. CONCLUSIONS: Using machine learning techniques, XGBoost to predict postoperative 90-day mortality, using diagnostic and operation codes, the prediction performance was improved significantly over the previous risk assessment models such as OFRS and HFRS.

Lossless Reconstruction of Convolutional Neural Network for Channel-Based Network Pruning.

Network pruning reduces the number of parameters and computational costs of convolutional neural networks while maintaining high performance. Although existing pruning methods have achieved excellent results, they do not consider reconstruction after pruning in order to apply the network to actual devices. This study proposes a reconstruction process for channel-based network pruning. For lossless reconstruction, we focus on three components of the network: the residual block, skip connection, and convolution layer. Union operation and index alignment are applied to the residual block and skip connection, respectively. Furthermore, we reconstruct a compressed convolution layer by considering batch normalization. We apply our method to existing channel-based pruning methods for downstream tasks such as image classification, object detection, and semantic segmentation. Experimental results show that compressing a large model has a 1.93% higher accuracy in image classification, 2.2 higher mean Intersection over Union (mIoU) in semantic segmentation, and 0.054 higher mean Average Precision (mAP) in object detection than well-designed small models. Moreover, we demonstrate that our method can reduce the actual latency by 8.15× and 5.29× on Raspberry Pi and Jetson Nano, respectively.

Impact of Body Mass Index and Sarcopenia on Short- and Long-Term Outcomes After Esophageal Cancer Surgery: An Observational Study.

BACKGROUND: The effects of specific body mass index (BMI) category and sarcopenia within each BMI category on outcomes in patients undergoing esophageal surgery with esophageal squamous cell carcinoma have not been thoroughly examined. METHODS: This study included 1141 patients. Sarcopenia was determined with a total psoas muscle cross-sectional area at the level of the third lumbar vertebra in computed tomography. The outcomes were long-term survival, including overall survival (OS) and recurrence-free survival (RFS), and postoperative complications. RESULTS: The overweight and no sarcopenia group was considered as the reference. After adjusting covariates, the underweight and the normal weight and sarcopenia groups both showed worse OS (underweight group: hazard ratio [HR] 2.04, 95% confidence interval [CI] 1.33-3.13, p = 0.001; normal weight and sarcopenia group: HR 1.93, 95% CI 1.39-2.69, p < 0.001) and worse RFS (underweight group: HR 1.78, 95% CI 1.19-2.67, p = 0.005; normal weight and sarcopenia group: HR 1.70, 95% CI 1.25-2.30, p = 0.001). In addition, the underweight group (odds ratio [OR] 4.74, 95% CI 2.05-10.96, p < 0.001), the normal weight and sarcopenia group (OR 3.26, 95% CI 1.60-6.62, p = 0.001), the overweight and sarcopenia group (OR 2.54, 95% CI 1.14-5.68, p = 0.023), and the obese and no sarcopenia group (OR 2.44, 95% CI 1.14-5.22, p = 0.021) were at significantly higher risk of postoperative 30-day composite complications. CONCLUSIONS: Compared with the overweight and no sarcopenia group, the underweight and the normal weight and sarcopenia groups were associated with worse short- and long-term outcomes.

Plasticity and Enzymatic Degradation Coupled With Volumetric Growth in Pulmonary Hypertension Progression.

Pulmonary hypertension (PH) is one of the least understood and highly elusive cardiovascular conditions associated with elevated pulmonary arterial pressure. Although the disease mechanisms are not completely understood, evidence has accumulated from human and animal studies that irreversible processes of pulmonary arterial wall damage, compensated by stress-mediated growth, play critical roles in eliciting the mechanisms of disease progression. The aim of this study is to develop a thermodynamic modeling structure of the pulmonary artery to consider coupled plastic-degradation-growth irreversible processes to investigate the mechanical roles of the dissipative phenomena in the disease progression. The proposed model performs a model parameter study of plastic deformation and degradation processes coupled with dissipative growth subjected to elevated pulmonary arterial pressure and computationally generates in silico simulations of PH progression using the clinical features of PH, found in human morphological and mechanical data. The results show that considering plastic deformation can provide a much better fitting of the ex vivo inflation tests than a widely used pure hyperelastic model in higher pressure conditions. In addition, the parameter sensitivity study illustrates that arterial damage and growth cause the increased stiffness, and the full simulation (combining elastic-plastic-degradation-growth models) reveals a key postpathological recovery process of compensating vessel damage by vascular adaptation by reducing the rate of vessel dilation and mediating vascular wall stress. Finally, the simulation results of luminal enlargement, arterial thickening, and arterial stiffness for an anisotropic growth are found to be close to the values from the literature.

Postoperative changes in left ventricular systolic function after combined mitral and aortic valve replacement in patients with rheumatic heart disease.

BACKGROUNDS: We sought to identify short- and long-term changes in postoperative left ventricular systolic function in patients with rheumatic heart disease (RHD) who underwent combined aortic and mitral valve replacement. METHODS: We analyzed 146 patients according to their preoperative left ventricular ejection fraction (LVEF) (113 with preoperative LVEF ≥50% and 33 with preoperative LVEF <50%). A restricted cubic spline model was used to assess the effect of time on the postoperative changes in echocardiographic parameters. RESULTS: There were no significant difference in preoperative and immediately postoperative LVEF before discharge in either group. During median follow-up of 3.2 years (interquartile range: 1.3-4.7 years) after surgery, postoperative LVEF increased slightly and then plateaued in patients with preoperative LVEF ≥50%, whereas it increased over 3-4 years after surgery and then gradually decreased in patients with preoperative LVEF <50% (p < .001). CONCLUSION: Long-term postoperative LVEF showed a downward trend in RHD patients with reduced preoperative LVEF, whereas it reached a plateau in RHD patients with normal preoperative LVEF.

Stable and high-performance piezoelectric sensor via CVD grown WS2.

Piezoelectric materials are widely used as electromechanical couples for a variety of sensors and actuators in nanoscale electronic devices. The majority of piezoelectric devices display lateral patterning of counter electrodes beside active materials such as two-dimensional transition metal dichalcogenides (2D TMDs). As a result, their piezoelectric output response is strongly dependent on the lattice orientation of the 2D TMD crystal structure, limiting their piezoelectric properties. To overcome this issue, we fabricated a vertical sandwich design of a piezoelectric sensor with a conformal contact to enhance the overall piezoelectric performance. In addition, we enhanced the piezoelectric properties of 2D WS2 by carrying out a unique solvent-vapor annealing process to produce a sulfur-deficient WS2(1-x) structure that yielded a 3-fold higher piezoelectric response voltage (96.74 mV) than did pristine WS2 to a 3 kPa compression. Our device was also found to be stable: it retained its piezoelectric performance even after a month in an ambient atmospheric condition. Our study has revealed a facile methodology for fabricating large-scale piezoelectric devices using an asymmetrically engineered 2D WS2 structure.

Perioperative rupture risk of unruptured intracranial aneurysms in cardiovascular surgery.

Although unruptured intracranial aneurysms are increasingly being diagnosed incidentally, perioperative rupture risk of unruptured intracranial aneurysm in patients undergoing cardiovascular surgery remains unclear. Therefore, we conducted an observational study to assess the prevalence and perioperative rupture risk of unruptured intracranial aneurysm in patients undergoing cardiovascular surgery. Adult patients (n = 4864) who underwent cardiovascular surgery between January 2010 and December 2016 were included. We assessed the prevalence of unruptured intracranial aneurysms in these patients using preoperative neurovascular imaging. The incidence of postoperative 30-day subarachnoid haemorrhage from aneurysmal rupture was investigated in patients undergoing cardiovascular surgery with unruptured intracranial aneurysm. Postoperative outcomes were compared between patients with unruptured intracranial aneurysm and those without unruptured intracranial aneurysm. Of the 4864 patients (39.6% females; mean ± standard deviation age, 62.3 ± 11.3 years), 353 patients had unruptured intracranial aneurysms (prevalence rate, 7.26%; 95% confidence interval, 6.52-8.06%). Of these, eight patients received surgical or endovascular treatment before surgery and 345 patients underwent cardiovascular surgery with unruptured intracranial aneurysms. Within 30 days postoperatively, subarachnoid haemorrhage occurred only in one patient, and the cumulative postoperative 30-day subarachnoid haemorrhage incidence was 0.29% (95% confidence interval, 0.01% to 1.61%). The Kaplan-Meier estimated subarachnoid haemorrhage probabilities according to the unruptured intracranial aneurysm rupture risk scores were not higher than the previously reported risk in the general population. There were no significant differences in postoperative subarachnoid haemorrhage-free survival, haemorrhagic stroke-free survival, in-hospital mortality, and hospital length of stay between patients with unruptured intracranial aneurysm and those without unruptured intracranial aneurysm. In conclusion, the prevalence of unruptured intracranial aneurysm in patients undergoing cardiovascular surgery is higher than in the general population. However, incidentally detected unruptured intracranial aneurysms are not linked to an increased risk of subarachnoid haemorrhage or adverse postoperative outcomes. These findings may help determine the optimal management of unruptured intracranial aneurysms before cardiovascular surgery.

Toward an interpretable Alzheimer's disease diagnostic model with regional abnormality representation via deep learning.

In this paper, we propose a novel method for magnetic resonance imaging based Alzheimer's disease (AD) or mild cognitive impairment (MCI) diagnosis that systematically integrates voxel-based, region-based, and patch-based approaches into a unified framework. Specifically, we parcellate the brain into predefined regions based on anatomical knowledge (i.e., templates) and derive complex nonlinear relationships among voxels, whose intensities denote volumetric measurements, within each region. Unlike existing methods that use cubical or rectangular shapes, we consider the anatomical shapes of regions as atypical patches. Using complex nonlinear relationships among voxels in each region learned by deep neural networks, we extract a "regional abnormality representation." We then make a final clinical decision by integrating the regional abnormality representations over the entire brain. It is noteworthy that the regional abnormality representations allow us to interpret and understand the symptomatic observations of a subject with AD or MCI by mapping and visualizing these observations in the brain space. On the baseline MRI dataset from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort, our method achieves state-of-the-art performance for four binary classification tasks and one three-class classification task. Additionally, we conducted exhaustive experiments and analysis to validate the efficacy and potential of our method.

Differences in anxiety sensitivity factors between anxiety and depressive disorders.

BACKGROUND: Anxiety sensitivity (AS) refers to the tendency to fear physical sensations associated with anxiety due to concerns about potential physical, social, or cognitive consequences. Many previous studies were limited by the use of the anxiety sensitivity index (ASI) or the ASI-revised (ASI-R), which are both measurements with unitary or unstable structures. No recent study that has utilized the ASI-3 examined the relations between AS dimensions and depression. Thus, we examined multiple relationships between AS and anxiety disorders and depression using the ASI-3. METHODS: The total sample consisted of 667 outpatients, diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders fourth text revision as assessed by a structured clinical interview. There were eight patient groups: multiple anxiety disorder, major depressive disorder (MDD), panic disorder (PD), social phobia (SP), obsessive-compulsive disorder (OCD), posttraumatic stress disorder (PTSD), generalized anxiety disorder (GAD), and anxiety disorder not otherwise specified (AD NOS). We conducted one-way analysis of variances and post hoc tests to compare the ASI-3 total and subscale scores across the groups. RESULTS: The physical concern score was higher in patients with PD than patients with MDD, SP, OCD, or GAD. The social concern score was higher in the SP group than those with MDD, PD, GAD, and AD NOS. Patients with GAD and PTSD showed higher cognitive concern scores than the patients with PD. CONCLUSION: Results partially replicated the relationship between PD and physical concern, between SP and social concern, and between GAD and cognitive concern examining the relationships between AS dimensions and anxiety disorders.

The relationship of preoperative estimated glomerular filtration rate and outcomes after cardiovascular surgery in patients with normal serum creatinine: a retrospective cohort study.

BACKGROUND: Although serum creatinine concentration has been traditionally used as an index of renal function in clinical practice, it is considered relatively inaccurate, especially in patients with mild renal dysfunction. This study investigated the usefulness of preoperative estimated glomerular filtration rate (eGFR) in predicting complications after cardiovascular surgery in patients with normal serum creatinine concentrations. METHODS: This study included 2208 adults undergoing elective cardiovascular surgery. Preoperative eGFR was calculated using Chronic Kidney Disease Epidemiology Collaboration equations. The relationships between preoperative eGFR and 90 day postoperative composite major complications were analyzed, including 90 day all-cause mortality, major adverse cardiac and cerebrovascular events, severe acute kidney injury, respiratory and gastrointestinal complications, wound infection, sepsis, and multi-organ failure. RESULTS: Of the 2208 included patients, 185 (8.4%) had preoperative eGFR < 60 mL/min/1.73 m2 and 328 (14.9%) experienced postoperative major complications. Multivariable logistic regression analyses showed that preoperatively decreased eGFR was independently associated with an increased risk of composite 90 day major postoperative complications (adjusted odds ratio: 1.232; 95% confidence interval [CI]: 1.148-1.322; P <  0.001). eGFR was a better discriminator of composite 90 day major postoperative complications than serum creatinine, with estimated c-statistics of 0.724 (95% CI: 0.694-0.754) for eGFR and 0.712 (95% CI: 0.680-0.744) for serum creatinine (P = 0.008). CONCLUSIONS: Decreased eGFR was significantly associated with an increased risk of major complications after cardiovascular surgery in patients with preoperatively normal serum creatinine concentrations.

Effect of operative time on the outcome of patients undergoing off-pump coronary artery bypass surgery.

BACKGROUND: Several studies have been reporting circadian variation in postoperative morbidity and mortality. We investigated whether the outcomes after off-pump coronary artery bypass (OPCAB) surgery are influenced by the operation start time. METHODS: We retrospectively evaluated 1690 patients who received elective OPCAB surgery from January 2006 to December 2016. The patients were divided into two groups according to the operation start time (morning or afternoon). The primary outcome was the occurrence of a major adverse cardiac event (MACE) within 30 days after surgery and death within 1 year after surgery. Propensity matching analysis and multivariable analyses were performed to evaluate the relationship between the operation start time and postoperative outcomes. RESULTS: There were no significant differences in the overall 1-year mortality rate (2.2% vs 2.9%; P = .568 in the entire cohort and 1.5% vs 2.7%; P = .259 in the propensity-matched cohort) and 30-day MACE rate (8.9% vs 10.4%; P = .378 in the entire cohort and 9.4% vs 10.0%; P = .827 in the propensity-matched cohort) between the morning and afternoon surgery group. Multivariable regression analyses also did not show any significant relationship between the operation start time and postoperative outcomes. CONCLUSIONS: In elective OPCAB surgery, the operative time was not associated with an increased risk of postoperative mortality and complications.

Effect of restrictive fluid therapy with hydroxyethyl starch during esophagectomy on postoperative outcomes: a retrospective cohort study.

BACKGROUND: To improve prognosis after esophageal surgery, intraoperative fluid optimization is important. Herein, we hypothesized that hydroxyethyl starch administration during esophagectomy reduce the total amount of fluid infused and it could have a positive effect on postoperative complication occurrence and mortality. METHODS: All consecutive adult patients who underwent elective esophageal surgery for cancer were studied. The primary outcome was the development of composite complications including death, cardio-cerebrovascular complications, respiratory complications, renal complications, gastrointestinal complications, sepsis, empyema or abscess, and multi-organ failure. The relationship between perioperative variables and composite complication was evaluated using multivariable logistic regression. RESULTS: Of 892 patients analyzed, composite complications developed in 271 (30.4%). The higher hydroxyethyl starch ratio in total fluid had a negative relationship with the total fluid infusion amount (r = - 0.256, P <  0.001). In multivariable analysis, intraoperatively administered total fluid per weight per hour (odds ratio, 1.248; 95% CI, 1.153-1.351; P <  0.001) and HES-to-crystalloid ratio (odds ratio, 2.125; 95% CI, 1.521-2.969; P <  0.001) were associated with increased risks of postoperative composite outcomes. CONCLUSIONS: Although hydroxyethyl starch administration reduces the total fluid infusion amount during esophageal surgery for cancer, intravenous hydroxyethyl starch infusion is associated with an increasing risk of postoperative composite complications.

Preoperative dexamethasone for acute post-thoracotomy analgesia: a randomized, double-blind, placebo-controlled study.

BACKGROUND: The analgesic effects of dexamethasone have been reported previously, and the present study determined the effects of preoperative dexamethasone on postoperative pain in patients who received thoracotomy. METHODS: Forty patients participated in this randomized, double-blind study. All patients received either dexamethasone via a 0.1 mg/kg intravenous bolus before anesthetic induction or an equal volume of saline. Postoperative analgesia was provided to both groups via epidural patient-controlled analgesia (PCA), which consisted of 250 µg of sufentanil in 250 mL of ropivacaine (0.18%) for 72 h. The primary outcome was the cumulative consumption of epidural PCA at postoperative 24 and 72 h. The secondary outcomes were the pain intensity scores during resting and coughing at postoperative 24 and 72 h, quality of recovery, total amount of rescue analgesics required, and length of hospital stay. RESULTS: No significant differences was observed in the consumption of epidural PCA between the control and dexamethasone infusion groups at 24 h (63.6 [55.9-72.7] vs. 68.5 [60.2-89.0] ml, P = 0.281) and 72 h (199.4 [172.4-225.1] vs. 194.7 [169.1-252.2] ml, P = 0.890). Moreover, there was no significant difference in the pain intensity scores during resting and coughing at postoperative 24 and 72 h, quality of recovery, total amount of rescue analgesics required, and length of hospital stay. CONCLUSION: A single intravenous administration of dexamethasone during the preoperative period does not reduce opioid consumption and post-thoracotomy pain. TRIAL REGISTRATION: The study was registered at http://cris.nih.go.kr ( KCT0000359 ) and was conducted from December 2011 to October 2012.

Association between red blood cell transfusion and long-term mortality in patients with cancer of the esophagus after esophagectomy.

The impact of red blood cell transfusion on long-term mortality has not been well characterized in patients with cancer of the esophagus after esophagectomy. Our retrospective observational study investigated 611 patients with cancer of the esophagus after esophagectomy from January 2005 to December 2012. Perioperative red blood cell transfusion was defined as red blood cell transfusion during intraoperative and postoperative period. One hundred ninety-six (32.1%) patients received red blood cell transfusion. During follow-up period, 153 (36.9%) patients without red blood cell transfusion and 120 (61.2%) patients with red blood cell transfusion died. Multivariable analysis identified that there was an incremental association between the amount of red blood cell transfusion and long-term mortality (hazard ratio 1.06, 95% confidence interval 1.04-1.08, P < 0.001). The association between red blood cell transfusion and worse long-term mortality was also demonstrated in propensity-matched patients (hazard ratio 1.62, 95% confidence interval 1.15-2.28, P = 0.006). Therefore, there might be an independent association between perioperative red blood cell transfusion and worse long-term mortality in patients with cancer of the esophagus after esophagectomy. Furthermore, there was an incremental increase in long-term mortality in patients who was transfused with red blood cell during perioperative period.

Prognostic Impacts of Increases in Amino Transaminases Following Coronary Artery Bypass Grafting on Mortality.

OBJECTIVE: To evaluate the prognostic impacts of postoperative increases in serum amino transaminases on 1-year mortality in patients who underwent coronary artery bypass graft. DESIGN: A retrospective analysis. SETTING: A tertiary care university hospital. PARTICIPANTS: A total of 1,950 patients who underwent coronary artery bypass graft. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Aspartate amino transaminase and alanine amino transaminase ratios were calculated as the ratio between the peak aspartate amino transaminase and alanine amino transaminase within the first 5 post-operative days and their respective upper limit of normal values. A ratio of 2.0 was seen to be the minimum for which a difference in 1-year mortality could be detected in univariate analysis, when considering simultaneously both aspartate amino transaminase and alanine amino transaminase ratios. Multivariable analysis showed an association between an aspartate amino transaminase ratio > 2.0 and increased 1-year mortality (hazard ratio [HR] 2.68, 95% confidence interval [CI] 1.42-5.05, P = 0.002), and also between both an aspartate amino transaminase and alanine amino transaminase ratio > 2.0 and increased 1-year mortality (HR 3.90, 95% CI 1.87-8.14, P < 0.001). However, increases in alanine amino transaminase only above the upper limit of normal were not associated with increased 1-year mortality. CONCLUSIONS: Postoperative increases in aspartate amino transaminase only and increases in both aspartate amino transaminase and alanine amino transaminase greater than twice the upper limit of normal were associated with increased 1-year mortality in patients undergoing coronary artery bypass graft.

Prediction of the optimal depth for superior vena cava cannulae with cardiac computed tomography during minimally invasive cardiac surgery: a prospective observational cohort study.

BACKGROUND: The determination of the adequate depth of superior vena cava cannulae during minimally invasive cardiac surgery is important for warranting venous drainage and preventing complications during cardiopulmonary bypass. We investigated whether preoperative cardiac computed tomography might be useful for predicting the optimal depth of superior vena cava cannulae. METHODS: The patients who required superior vena cava cannulation and had cardiac tomographic image among those scheduled to undergo a minimally invasive cardiac surgery were evaluated. The distance between the upper border of the clavicular sternal head and the superior vena cava-right atrium junction was measured on cardiac computed tomography. Equivalence test for the difference between the distance measured on cardiac computed tomography and the distance verified by surgeon's direct inspection in the surgical field was performed. The range -1 cm to 1 cm was predefined as an equivalence region. In addition, the distances between the upper border of the clavicular sternal head and the carina level on chest radiography were measured to compare the relative position of carina with regard to the superior vena cava-right atrium junction. RESULTS: A total of 46 patients were evaluated. The distance from the upper border of the clavicular sternal head to the superior vena cava-right atrium junction measured on cardiac computed tomography and the distance verified by surgeon's inspection was equivalent, with the 95% confidence interval for the mean difference within the equivalence region (0.05-0.52, P < 0.0001). The carina level on chest radiography was found at least 2 cm above the superior vena cava-right atrium junction in all patients. CONCLUSIONS: Preoperative cardiac computed tomography might be valuable for predicting the adequate depth of superior vena cava cannulae. Additionally, the carina on chest radiography might indicate a useful landmark for proper position of central venous catheter. TRIAL REGISTRATION: This study has been registered at Clinical Research Information Service on 6 July 2012 (KCT0000477) .

Association Between Arterial Carbon Dioxide Tension and Outcome in Patients Admitted to the Intensive Care Unit After Coronary Artery Bypass Surgery.

OBJECTIVES: The aim of this study was to determine the association between PaCO2 and patient outcome in patients admitted to the intensive care unit (ICU) after coronary artery bypass grafting (CABG). DESIGN: A retrospective cohort study. SETTING: Single-institutional, university hospital. PARTICIPANTS: All patients admitted to the ICU after CABG between January 2009 and December 2012. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Based on PaCO2 status during the first 24 hours after CABG, 1,011 patients were classified into 4 groups: normocapnia, hypocapnia, hypercapnia, and dual hyper/hypocapnia. The 30-day mortality rate was 0.7% (n = 4) for normocapnia, 1.5% (n = 4) for hypocapnia, 2.2% (n = 3) for hypercapnia, and 7.5% (n = 4) for the dual-exposure group. The extubation times were 13.3±21.7 hours, 15.8±21.37 hours, 21.79±39.70 hours, and 42.29±75.35 hours, respectively. After adjusting for confounding variables, the dual hypocapnia and hypercapnia exposure group was associated with increased 30-day mortality (odds ratio [OR] = 8.08; 95% confidence interval [CI], 1.82-35.86; p = 0.006) and delayed extubation (OR = 2.40; 95% CI, 1.24-4.64; p = 0.010). CONCLUSIONS: Exposure to both hypocapnia and hypercapnia within 24 hours after CABG was associated independently with increased risk of 30-day mortality and delayed extubation. Exposure to either hypocapnia or hypercapnia alone was not associated with patient outcome.

Effect of Exogenous Albumin on the Incidence of Postoperative Acute Kidney Injury in Patients Undergoing Off-pump Coronary Artery Bypass Surgery with a Preoperative Albumin Level of Less Than 4.0 g/dl.

BACKGROUND: Hypoalbuminemia may increase the risk of acute kidney injury (AKI). The authors investigated whether the immediate preoperative administration of 20% albumin solution affects the incidence of AKI after off-pump coronary artery bypass surgery. METHODS: In this prospective, single-center, randomized, parallel-arm double-blind trial, 220 patients with preoperative serum albumin levels less than 4.0 g/dl were administered 100, 200, or 300 ml of 20% human albumin according to the preoperative serum albumin level (3.5 to 3.9, 3.0 to 3.4, or less than 3.0 g/dl, respectively) or with an equal volume of saline before surgery. The primary outcome measure was AKI incidence after surgery. Postoperative AKI was defined by maximal AKI Network criteria based on creatinine changes. RESULTS: Patient characteristics and perioperative data except urine output during surgery were similar between the two groups studied, the albumin group and the control group. Urine output (median [interquartile range]) during surgery was higher in the albumin group (550 ml [315 to 980]) than in the control group (370 ml [230 to 670]; P = 0.006). The incidence of postoperative AKI in the albumin group was lower than that in the control group (14 [13.7%] vs. 26 [25.7%]; P = 0.048). There were no significant between-group differences in severe AKI, including renal replacement therapy, 30-day mortality, and other clinical outcomes. There were no significant adverse events. CONCLUSION: Administration of 20% exogenous albumin immediately before surgery increases urine output during surgery and reduces the risk of AKI after off-pump coronary artery bypass surgery in patients with a preoperative serum albumin level of less than 4.0 g/dl.