Effect of salt intake on beat‐to‐beat blood pressure nonlinear dynamics and entropy in salt‐sensitive versus salt‐protected rats

Blood pressure exhibits substantial short‐ and long‐term variability (BPV). We assessed the hypothesis that the complexity of beat‐to‐beat BPV will be differentially altered in salt‐sensitive hypertensive Dahl rats (SS) versus rats protected from salt‐induced hypertension (SSBN13) maintained on high‐salt versus low‐salt diet. Beat‐to‐beat systolic and diastolic BP series from nine SS and six SSBN13 rats (http://www.physionet.org) were analyzed following 9 weeks on low salt and repeated after 2 weeks on high salt. BP complexity was quantified by detrended fluctuation analysis (DFA), short‐ and long‐range scaling exponents (αS and αL), sample entropy (SampEn), and traditional standard deviation (SD) and coefficient of variation (CV(%)). Mean systolic and diastolic BP increased on high‐salt diet (P < 0.01) particularly for SS rats. SD and CV(%) were similar across groups irrespective of diet. Salt‐sensitive and ‐protected rats exhibited similar complexity indices on low‐salt diet. On high salt, (1) SS rats showed increased scaling exponents or smoother, systolic (P = 0.007 [αL]) and diastolic (P = 0.008 [αL]) BP series; (2) salt‐protected rats showed lower SampEn (less complex) systolic and diastolic BP (P = 0.046); and (3) compared to protected SSBN13 rats, SS showed higher αL for systolic (P = 0.01) and diastolic (P = 0.005) BP. Hypertensive SS rats are more susceptible to high salt with a greater rise in mean BP and reduced complexity. Comparable mean pressures in sensitive and protective rats when on low‐salt diet coupled with similar BPV dynamics suggest a protective role of low‐salt intake in hypertensive rats. This effect likely reflects better coupling of biologic oscillators.We investigated the non‐linear dynamical properties of blood pressure variability, specifically complexity analysis and detrended fluctuation analysis (DFA), of the systolic and diastolic blood pressure time series in 9 salt sensitive and 6 protected rats. We showed that salt sensitive rats exhibit varying non linear BP dynamics compared to protected rats (smoother time series), irrespective of diet; we also showed the differential impat of salt intake on complexity and DFA metrics in both strains of rats.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/122419/1/phy212823_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/122419/2/phy212823.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/122419/3/phy212823-sup-0001-SupInfo.pd

The effect of completeness of revascularization during CABG with single versus multiple arterial grafts

IntroductionIncomplete coronary revascularization is associated with suboptimal outcomes. We investigated the longâ term effects of Incomplete, Complete, and Supraâ complete revascularization and whether these effects differed in the setting of singleâ arterial and multiâ arterial coronary artery bypass graft (CABG).MethodsWe analyzed 15â year mortality in 7157 CABG patients (64.1â ±â 10.5 years; 30% women). All patients received a left internal thoracic artery to left anterior descending coronary artery graft with additional venous grafts only (singleâ arterial) or with at least one additional arterial graft (multiâ arterial) and were grouped based on a completeness of revascularization index (CRIâ =â number of grafts minus the number of diseased principal coronary arteries): Incomplete (CRIâ â ¤â â 1 [Nâ =â 320;4.5%]); Complete (CRIâ =â 0 [Nâ =â 2882;40.3%]; reference group); and two Supraâ complete categories (CRIâ =â +1[Nâ =â 3050; 42.6%]; CRIâ â ¥â +â 2 [Nâ =â 905; 12.6%]). Riskâ adjusted mortality hazard ratios (AHR) were calculated using comprehensive propensity score adjustment by Cox regression.ResultsIncomplete revascularization was rare (4.5%) but associated with increased mortality in all patients (AHR [95% confidence interval]â =â 1.53 [1.29â 1.80]), those undergoing singleâ arterial CABG (AHRâ =â 1.27 [1.04â 1.54]) and multiâ arterial CABG (AHRâ =â 2.18 [1.60â 2.99]), as well as in patients with 3â Vessel (AHRâ =â 1.37 [1.16â 1.62]) and, to a lesser degree, with 2â Vessel (AHRâ =â 1.67 [0.53â 5.23]) coronary disease. Supraâ complete revascularization was generally associated with incrementally decreased mortality in all patients (AHR [CRIâ =â +1]â =â 0.94 [0.87â 1.03]); AHR [CRIâ â ¥â +2]â =â 0.74 [0.64â 0.85]), and was driven by a significantly decreased mortality risk in singleâ arterial CABG (AHR [CRIâ =â +1]â =â 0.90 [0.81â 0.99]; AHR [CRIâ â ¥â +2]â =â 0.64 [0.53â 0.78]); and 3â Vessel disease patients (AHR [CRIâ =â +1]â =â 0.94 [0.86â 1.04]; and AHR [CRIâ â ¥â +2]â =â 0.75 [0.63â 0.88]) with no impact in multiâ arterial CABG (AHR [CRIâ =â +1]â =â 1.07 [0.91â 1.26]; AHR [CRIâ â ¥â +2]â =â 0.93 [0.73â 1.17]).ConclusionsIncomplete revascularization is associated with decreased late survival, irrespective of grafting strategy. Alternatively, supraâ complete revascularization is associated with improved survival in patients with 3â Vessel CAD, and in singleâ arterial but not multiâ arterial CABG.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146364/1/jocs13810.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146364/2/jocs13810_am.pd

Associations of the plasma lipidome with mortality in the acute respiratory distress syndrome: a longitudinal cohort study

Abstract Background It is unknown if the plasma lipidome is a useful tool for improving our understanding of the acute respiratory distress syndrome (ARDS). Therefore, we measured the plasma lipidome of individuals with ARDS at two time-points to determine if changes in the plasma lipidome distinguished survivors from non-survivors. We hypothesized that both the absolute concentration and change in concentration over time of plasma lipids are associated with 28-day mortality in this population. Methods Samples for this longitudinal observational cohort study were collected at multiple tertiary-care academic medical centers as part of a previous multicenter clinical trial. A mass spectrometry shot-gun lipidomic assay was used to quantify the lipidome in plasma samples from 30 individuals. Samples from two different days were analyzed for each subject. After removing lipids with a coefficient of variation > 30%, differences between cohorts were identified using repeated measures analysis of variance. The false discovery rate was used to adjust for multiple comparisons. Relationships between significant compounds were explored using hierarchical clustering of the Pearson correlation coefficients and the magnitude of these relationships was described using receiver operating characteristic curves. Results The mass spectrometry assay reliably measured 359 lipids. After adjusting for multiple comparisons, 90 compounds differed between survivors and non-survivors. Survivors had higher levels for each of these lipids except for five membrane lipids. Glycerolipids, particularly those containing polyunsaturated fatty acid side-chains, represented many of the lipids with higher concentrations in survivors. The change in lipid concentration over time did not differ between survivors and non-survivors. Conclusions The concentration of multiple plasma lipids is associated with mortality in this group of critically ill patients with ARDS. Absolute lipid levels provided more information than the change in concentration over time. These findings support future research aimed at integrating lipidomics into critical care medicine.https://deepblue.lib.umich.edu/bitstream/2027.42/143134/1/12931_2018_Article_758.pd

Associations of the plasma lipidome with mortality in the acute respiratory distress syndrome: a longitudinal cohort study

Abstract Background It is unknown if the plasma lipidome is a useful tool for improving our understanding of the acute respiratory distress syndrome (ARDS). Therefore, we measured the plasma lipidome of individuals with ARDS at two time-points to determine if changes in the plasma lipidome distinguished survivors from non-survivors. We hypothesized that both the absolute concentration and change in concentration over time of plasma lipids are associated with 28-day mortality in this population. Methods Samples for this longitudinal observational cohort study were collected at multiple tertiary-care academic medical centers as part of a previous multicenter clinical trial. A mass spectrometry shot-gun lipidomic assay was used to quantify the lipidome in plasma samples from 30 individuals. Samples from two different days were analyzed for each subject. After removing lipids with a coefficient of variation > 30%, differences between cohorts were identified using repeated measures analysis of variance. The false discovery rate was used to adjust for multiple comparisons. Relationships between significant compounds were explored using hierarchical clustering of the Pearson correlation coefficients and the magnitude of these relationships was described using receiver operating characteristic curves. Results The mass spectrometry assay reliably measured 359 lipids. After adjusting for multiple comparisons, 90 compounds differed between survivors and non-survivors. Survivors had higher levels for each of these lipids except for five membrane lipids. Glycerolipids, particularly those containing polyunsaturated fatty acid side-chains, represented many of the lipids with higher concentrations in survivors. The change in lipid concentration over time did not differ between survivors and non-survivors. Conclusions The concentration of multiple plasma lipids is associated with mortality in this group of critically ill patients with ARDS. Absolute lipid levels provided more information than the change in concentration over time. These findings support future research aimed at integrating lipidomics into critical care medicine.https://deepblue.lib.umich.edu/bitstream/2027.42/143134/1/12931_2018_Article_758.pd

Volume of packed red blood cells and fresh frozen plasma is associated with intraoperative hypocalcaemia during large volume intraoperative transfusion

BackgroundSevere hypocalcaemia is associated with increased transfusion in the trauma population. Furthermore, trauma patients developing severe hypocalcaemia have higher mortality and coagulopathy. Electrolyte abnormalities associated with massive transfusion have been less studied in the surgical population. Here, we tested the primary hypothesis that volume of packed red blood cells and fresh frozen plasma transfused intraoperatively is associated with lower nadir ionised calcium in the surgical population receiving massive resuscitation.MethodsWe performed a retrospective observational study at an academic quaternary care centre to characterise hypocalcaemia following large volume (4 or more units packed red blood cells) intraoperative transfusion. We used multivariable linear regression to assess if volume of transfusion with packed red blood cells and fresh frozen plasma were independently associated with a lower ionised calcium. We then used multivariable logistic regressions to assess the association between ionised calcium and transfusion with: (i) mortality, (ii) acute kidney injury, and (iii) postoperative coagulopathy.ResultsHypocalcaemia following large volume resuscitation in the operating room is a very frequent occurrence (70% of cases). After controlling for demographic variables and intraoperative variables, the volume transfused intraoperative was independently associated with hypocalcaemia on multivariable linear regression. Hypocalcaemia, intraoperative transfusion of packed red blood cells, and intraoperative transfusion of fresh frozen plasma were not shown to be associated with clinical outcomes.ConclusionsHypocalcaemia was associated with increased transfusion volume in this single‐centre study. Unlike the trauma population, hypocalcaemia was not associated with increased mortality during surgical care. Our findings suggest that despite improved practice patterns of calcium supplementation, intraoperative hypocalcaemia occurs with relatively high frequency following large volume intraoperative transfusion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/171170/1/tme12798.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/171170/2/tme12798_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/171170/3/tme12798-sup-0001-Supinfo.pd

Intraoperative risk factors of acute kidney injury following liver transplantation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/173103/1/lt26477.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/173103/2/lt26477_am.pd

Risk and Safety Perceptions Contribute to Transfusion Decisions in Coronary Artery Bypass Grafting

Variability persists in intraoperative red blood cell (RBC) transfusion rates, despite evidence supporting associated adverse sequelae. We evaluated whether beliefs concerning transfusion risk and safety are independently associated with the inclination to transfuse. We surveyed intraoperative transfusion decision-makers from 33 cardiac surgery programs in Michigan. The primary outcome was a provider’s reported inclination to transfuse (via a six-point Likert Scale) averaged across 10 clinical vignettes based on Class IIA or IIB blood management guideline recommendations. Survey questions assessed hematocrit threshold for transfusion (“hematocrit trigger”), demographic and practice characteristics, years and case-volume of practice, knowledge of transfusion guidelines, and provider attitude regarding perceived risk and safety of blood transfusions. Linear regression models were used to estimate the effect of these variables on transfusion inclination. Mixed effect models were used to quantify the variation attributed to provider specialties and hematocrit triggers. The mean inclination to transfuse was 3.2 (might NOT transfuse) on the survey Likert scale (SD: .86) across vignettes among 202/413 (48.9%) returned surveys. Hematocrit triggers ranged from 15% to 30% (average: 20.4%; SE: .18%). The inclination to transfuse in situations with weak-to-moderate evidence for supporting transfusion was associated with a provider’s hematocrit trigger (p < .01) and specialty. Providers believing in the safety of transfusions were significantly more likely to transfuse. Provider specialty and belief in transfusion safety were significantly associated with a provider’s hematocrit trigger and likelihood for transfusion. Our findings suggest that blood management interventions should target these previously unaccounted for blood transfusion determinants