Bioelectrical Impedance Phase Angle-Predictor of Blood Transfusion in Cardiac Surgery.

OBJECTIVE: To determine whether bioelectrical impedance-derived phase angle (PA) can be a predictor of red blood cell (RBC) transfusion in patients undergoing cardiac surgery. DESIGN: An observational retrospective study of prospectively collected data. SETTING: Single center, tertiary referral university hospital. PARTICIPANTS: The study sample comprised 642 adult patients undergoing elective cardiac surgery. INTERVENTIONS: Patient demographic and clinical variables were collected. The body composition of the patients was evaluated by bioelectrical impedance analysis (BIA) the day prior to surgery. The rates of postoperative RBC transfusion were recorded. MEASUREMENTS AND MAIN RESULTS: Among the 642 patients (67.8% men, median age of 66 [range 59-73]) included in the present study, 210 (32.7%) received at least 1 RBC unit postoperatively. Hypertension, preoperative stroke, renal failure, preoperative hemoglobin and hematocrit values, BIA-derived PA, aortic crossclamp time, and cardiopulmonary bypass (CPB) time were associated with the risk of RBC transfusion in the univariate analysis, and were included in the final multivariate regression model. Preoperative stroke (odds ratio [OR] 0.394; 95% confidence interval [CI]: 0.183-0.848; p = 0.017), preoperative hemoglobin values (OR 0.943; 95% CI: 0.928-0.960; p < 0.001), PA <15th percentile (OR 2.326; 95% CI: 1.351-4.000; p = 0.002), and CPB time (OR 1.013; 95% CI: 1.008-1.018; p < 0.001) were identified as independent predictors of RBC transfusion. CONCLUSION: Several factors were identified to be associated significantly with postoperative RBC transfusion in patients undergoing cardiac surgery. Among the conventional predictors, the value of the BIA-derived PA was indicated as a potent prognostic tool.

Concordance of the new ESPEN criteria with low phase angle in defining early stages of malnutrition in cardiac surgery.

BACKGROUND & AIMS: The aim of this study was to evaluate the incidence of malnutrition (MN) in cardiac surgery patients by implementing the new ESPEN diagnostic criteria and to determine whether these criteria are concordant with the bioelectrical impedance analysis (BIA) provided phase angle (PA) in predicting early stages of malnutrition. METHODS: A prospective study was conducted in a tertiary hospital. The nutritional state of the cardiac surgery patients was evaluated one day prior to cardiac surgery using the malnutrition screening tools NRS-2002, MUST and SF-MNA, and bioelectrical impedance analysis. Patients at risk of malnutrition were further studied in accordance with the ESPEN malnutrition diagnostic criteria. A BIA provided PA value of less than the 15th percentile of the age and gender group was set as a theoretical marker of early malnutrition. ROC AUC (receiver operating characteristic area under curve) analysis and other parameters were calculated to determine the concordance between the new ESPEN malnutrition diagnostic criteria and a low PA. RESULTS: The study comprised 549 enrolled cardiac surgery patients. MN or risk of MN in accordance with at least one nutritional status assessment tool was diagnosed in 372 (67.75%) patients. MN, according to the new ESPEN malnutrition diagnostic criteria, was only diagnosed in 31 (5.6%) patients. Low PA was detected in 124 patients (22.6%), providing a higher MN rate. The ROC analysis and other concordance parameters showed that the new ESPEN diagnostic criteria (AUC 0.560, p = 0.042) were not concordant with a low PA. CONCLUSION: Fewer patients are classified as malnourished by the new ESPEN definition as those identified by the BIA provided PA. Incorporation of the BIA provided PA into the new ESPEN definition may aid to diagnose the early stages of MN in the field of cardiac surgery.

Is the Trendelenburg position the only way to better visualize internal jugular veins?

BACKGROUND: A larger cross-sectional area (CSA) of the internal jugular vein (IJV) makes catheterization easier and the Trendelenburg position is used to achieve this. Unfortunately, it is not comfortable for conscious patients. The aim was to evaluate the impact of alternative manoeuvres on the enlargement of the CSA of the IJV and to compare these manoeuvres with the Trendelenburg position. MATERIALS AND METHODS: A prospective study of 63 healthy volunteers was conducted. Two-dimensional ultrasound images of right IJV (RIJV) and left IJV (LIJV) were recorded at the level of the cricoid cartilage in the supine position with and without head rotation by 30 degrees during various manoeuvres. RESULTS: The CSA of the RIJV and the LIJV significantly increased using hold of deep breath (mean size (cm2) RIJV 1.59 ± 0.82, LIJV 1.07 ± 0.64; both p < 0.001) and the Trendelenburg position (mean size (cm2) RIJV 1.5 ± 0.68, LIJV 0.99 ± 0.54; both p < 0.001). The 45-degree passive leg raise increased the CSA of only the RIJV (mean size (cm2) 1.17 ± 0.61, p = 0.024). These manoeuvres were compared with the Trendelenburg position. There was no significant difference in the size of the CSA using hold of deep breath on the LIJV (p = 0.08) and the RIJV (p = 0.203). The passive leg raise had a significantly weaker impact on the size of the CSA (p < 0.001 for both sides). CONCLUSIONS: Hold of deep breath and 45-degree passive leg raise (the latter limited for the right side only) are alternative manoeuvres to improve visualization of internal jugular veins for conscious patients. Hold of deep breath was as effective as the Trendelenburg position.

Malnutrition assessed by phase angle determines outcomes in low-risk cardiac surgery patients.

BACKGROUND & AIMS: Phase angle (PA), which is obtained from bioelectrical impedance analysis (BIA), is a non-invasive method for measuring altered electrical properties of biological tissues. It has been recognised as an objective prognostic marker of disease severity and frailty. The aim of this study is to determine whether PA is a marker of malnutrition and postoperative morbidity in low operative risk patients undergoing cardiac surgery. METHODS: A prospective study was conducted in a tertiary hospital. The nutritional state of the cardiac surgery patients was evaluated using BIA the day before the scheduled surgery. After applying selection criteria, 342 low operative risk patients were selected and classified into two groups in accordance with the PA value: a low PA group and a normal PA group. The correlation between low PA and low fat-free mass index (FFMI), a marker of malnutrition, was assessed. Associations between low PA and adverse postoperative outcomes, defined by the Society of Thoracic Surgeons postoperative risk evaluation model, were analysed. The impact of low PA on length of stay in an ICU and hospital was evaluated. RESULTS: Low PA was detected in 61 (17.8%) patients in the selected group, which consisted of low operative risk patients with a median Euroscore II value of 1.46 (IQR: 0.97-2.03) and was associated with FFMI with Pearson's R of 0.515 (p < 0.001). Low PA was associated with higher rates (13 [21.3%] vs. 30 [10.7%] p = 0.023) and risk of postoperative morbidity in univariate regression analysis (OR = 2.27, Cl 95% = 1.10-4.66, p = 0.026). Furthermore, low PA persisted as an independent factor in multivariate regression analysis (OR = 2.50, CI 95% 1.18-5.29, p = 0.016) adjusted for preoperative risk factors of postoperative morbidity. Evaluation of hospitalisation length revealed a tendency of a prolonged hospitalisation (>14 days) rate (31 [50.8%] vs. 105 [37.8%], p = 0.063) in the group with low PA. CONCLUSION: A low preoperative PA is an indicator of malnutrition and determines adverse outcomes after cardiac surgery. Further research is needed to evaluate clinical applications of the PA, such as a more accurate identification of malnourished cardiac surgery patients.

Preoperative risk factors of malnutrition for cardiac surgery patients.

BACKGROUND: Malnutrition (MN) is prevalent in cardiac surgery, but there are no specific preoperative risk factors of MN. The aim of this study is to assess the clinically relevant risk factors of MN for cardiac surgery patients. MATERIALS AND METHODS: The nutritional state of the patients was evaluated one day prior to surgery using a bioelectrical impedance analysis phase angle (PA). Two groups of patients were generated according to low PA: malnourished and well nourished. Risk factors of MN were divided into three clinically relevant groups: psychosocial and lifestyle factors, laboratory findings and disease-associated factors. Variables in each different group were entered into separate multivariate logistic regression models. RESULTS: A total of 712 patients were included in the study. The majority of them were 65-year old men after a CABG procedure. Low PA was present in 22.9% (163) of patients. The analysis of disease-related factors of MN revealed the importance of heart functions (NYHA IV class OR: 3.073, CI95%: 1.416-6.668, p = 0.007), valve pathology (OR: 1.825, CI95%: 1.182-2.819, p = 0.007), renal insufficiency (OR: 4.091, CI95%: 1.995-8.389, p < 0.001) and body mass index (OR: 0.928, CI95%: 0.890-0.968, p < 0.001). Laboratory values related to MN were levels of haemoglobin (OR: 0.967, CI95%: 0.951-0.983, p < 0.001) and C-reactive protein (OR: 1.015, CI95%: 1.002-1.028, p = 0.0279). The lifestyle variables that qualified as risk factors concerned the intake of food (OR: 3.030, CI95%: 1.353-6.757, p = 0.007) and mobility (OR: 2.770, CI95%: 1.067-7.194, p = 0.036). CONCLUSIONS: MN risk factors comprise three different clinical groups: psychosocial and lifestyle factors, laboratory findings and disease-associated factors. The patients who are most likely to be malnourished are those with valve pathology, severe imparted heart function, insufficient renal function and high inflammatory markers. Also these patients have decreased mobility and food intake.

Impact of malnutrition on postoperative delirium development after on pump coronary artery bypass grafting.

BACKGROUND & AIMS: Even though malnutrition is frequently observed in cardiac population outcome data after cardiac surgery in malnourished patients is very rare. No thorough research was done concerning the impact of malnutrition on neuropsychological outcomes after cardiac surgery. The aim of our study was to analyze the incidence of postoperative delirium development in malnourished patients undergoing on pump bypass grafting. METHODS: We performed a cohort study of adults admitted to Vilnius University Hospital Santariskiu Clinics for elective coronary artery bypass grafting. The nutritional status of the patients was assessed by Nutritional Risk Screening 2002 (NRS-2002) questionnaire the day before surgery. Patients were considered as having no risk of malnutrition when NRS-2002 score was less than 3 and at risk of malnutrition when NRS-2002 score was ≥3. During ICU stay patients were screened for postoperative delirium development using the CAM-ICU method. and divided into two groups: delirium and non delirium. The statistical analysis was preformed to evaluate the differences between the two independent groups. The logistic regression model was used to evaluate the potential preoperative and intraoperative risk factors of postoperative delirium. RESULTS: Ninety-nine patients were enrolled in the study. Preoperative risk of malnutrition was detected in 24 % (n = 24) of the patients. The incidence of early postoperative delirium in overall study population was 8.0 % (n = 8). The incidence of the patients at risk of malnutrition was significantly higher in the delirium group (5 (62.5 %) vs 19 (20.9 %), p <0.0191). In multivariate logistic regression analysis risk of malnutrition defined by NRS 2002 was an independent preoperative and intraoperative risk factor of postoperative delirium after coronary artery bypass grafting (OR: 6.316, 95 % CI: 1.384-28.819 p = 0.0173). CONCLUSIONS: Preoperative malnutrition is common in patients undergoing elective coronary artery bypass grafting. Nutrition deprivation is associated with early postoperative delirium after on pump coronary artery bypass grafting.