Kidney-specific biomarkers for predicting acute kidney injury following cardiac arrest.

AIM: To evaluate the performance of kidney-specific biomarkers (neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and cystatin-C) in early detection of acute kidney injury (AKI) following cardiac arrest (CA) when compared to serum creatinine. METHODS: Adult CA patients who had kidney-specific biomarkers of AKI collected within 12 h of return of spontaneous circulation (ROSC) were included. The association between renal biomarker levels post-ROSC and the development of KDIGO stage III AKI within 7 days of enrollment were assessed as well as their predictive value of future AKI development, neurological outcomes, and survival to discharge. RESULTS: Of 153 patients, 54 (35%) developed stage III AKI within 7 days, and 98 (64%) died prior to hospital discharge. Patients who developed stage III AKI, compared to those who did not, had higher median levels of creatinine, NGAL, and cystatin-C (p < 0.001 for all). There was no statistically significant difference in KIM-1 between groups. No biomarker outperformed creatinine in the ability to predict stage III AKI, neurological outcomes, or survival outcomes (p > 0.05 for all). However, NGAL, cystatin-C, and creatinine all performed better than KIM-1 in their ability to predict AKI development (p < 0.01 for all). CONCLUSION: In post-CA patients, creatinine, NGAL, and cystatin-C (but not KIM-1) measured shortly after ROSC were higher in patients who subsequently developed AKI. No biomarker was statistically superior to creatinine on its own for predicting the development of post-arrest AKI.

Intraoperative respiratory and hemodynamic strategies for reducing nausea, vomiting, and pain after surgery: Systematic review and meta-analysis.

BACKGROUND: Despite improved medical treatment strategies, postoperative pain, nausea, and vomiting remain major challenges. This systematic review investigated the relationship between perioperative respiratory and hemodynamic interventions and postoperative pain, nausea, and vomiting. METHODS: PubMed and Embase were searched on March 8, 2021 for randomized clinical trials investigating the effect of perioperative respiratory or hemodynamic interventions in adults undergoing non-cardiac surgery. Investigators reviewed trials for relevance, extracted data, and assessed risk of bias. Meta-analyses were performed when feasible. GRADE was used to assess the certainty of the evidence. RESULTS: This review included 65 original trials; of these 48% had pain, nausea, and/or vomiting as the primary focus. No reduction of postoperative pain was found in meta-analyses when comparing recruitment maneuvers with no recruitment, high (80%) to low (30%) fraction of oxygen, low (5-7 ml/kg) to high (9-12 ml/kg) tidal volume, or goal-directed hemodynamic therapy to standard care. In the meta-analysis comparing recruitment maneuvers with no recruitment maneuvers, patients undergoing laparoscopic gynecological surgery had less shoulder pain 24 h postoperatively (mean difference in the numeric rating scale from 0 to 10: -1.1, 95% CI: -1.7, -0.5). In meta-analyses, comparing high to low fraction of inspired oxygen and goal-directed hemodynamic therapy to standard care in patients undergoing abdominal surgery, the risk of postoperative nausea and vomiting was reduced (odds ratio: 0.45, 95% CI: 0.24, 0.87 and 0.48, 95% CI: 0.27, 0.85). The certainty in the evidence was mostly very low to low. The results should be considered exploratory given the lack of prespecified hypotheses and corresponding risk of Type 1 errors. CONCLUSION: There is limited evidence regarding the impact of intraoperative respiratory and hemodynamic interventions on postoperative pain or nausea and vomiting. More definitive trials are needed to guide clinical care within this area.

Ventilation Strategies During General Anesthesia for Noncardiac Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: The optimal ventilation strategy during general anesthesia is unclear. This systematic review investigated the relationship between ventilation targets or strategies (eg, positive end-expiratory pressure [PEEP], tidal volume, and recruitment maneuvers) and postoperative outcomes. METHODS: PubMed and Embase were searched on March 8, 2021, for randomized trials investigating the effect of different respiratory targets or strategies on adults undergoing noncardiac surgery. Two investigators reviewed trials for relevance, extracted data, and assessed risk of bias. Meta-analyses were performed for relevant outcomes, and several subgroup analyses were conducted. The certainty of evidence was evaluated using Grading of Recommendations Assessment, Development and Evaluation (GRADE). RESULTS: This review included 63 trials with 65 comparisons. Risk of bias was intermediate for all trials. In the meta-analyses, lung-protective ventilation (ie, low tidal volume with PEEP) reduced the risk of combined pulmonary complications (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.28-0.49; 9 trials; 1106 patients), atelectasis (OR, 0.39; 95% CI, 0.25-0.60; 8 trials; 895 patients), and need for postoperative mechanical ventilation (OR, 0.36; 95% CI, 0.13-1.00; 5 trials; 636 patients). Recruitment maneuvers reduced the risk of atelectasis (OR, 0.44; 95% CI, 0.21-0.92; 5 trials; 328 patients). We found no clear effect of tidal volume, higher versus lower PEEP, or recruitment maneuvers on postoperative pulmonary complications when evaluated individually. For all comparisons across targets, no effect was found on mortality or hospital length of stay. No effect measure modifiers were found in subgroup analyses. The certainty of evidence was rated as very low, low, or moderate depending on the intervention and outcome. CONCLUSIONS: Although lung-protective ventilation results in a decrease in pulmonary complications, randomized clinical trials provide only limited evidence to guide specific ventilation strategies during general anesthesia for adults undergoing noncardiac surgery.

Fraction of inspired oxygen during general anesthesia for non-cardiac surgery: Systematic review and meta-analysis.

BACKGROUND: Controversy exists regarding the effects of a high versus a low intraoperative fraction of inspired oxygen (FiO2 ) in adults undergoing general anesthesia. This systematic review and meta-analysis investigated the effect of a high versus a low FiO2 on postoperative outcomes. METHODS: PubMed and Embase were searched on March 22, 2022 for randomized clinical trials investigating the effect of different FiO2 levels in adults undergoing general anesthesia for non-cardiac surgery. Two investigators independently reviewed studies for relevance, extracted data, and assessed risk of bias. Meta-analyses were performed for relevant outcomes, and potential effect measure modification was assessed in subgroup analyses and meta-regression. The evidence certainty was evaluated using GRADE. RESULTS: This review included 25 original trials investigating the effect of a high (mostly 80%) versus a low (mostly 30%) FiO2 . Risk of bias was intermediate for all trials. A high FiO2 did not result in a significant reduction in surgical site infections (OR: 0.91, 95% CI 0.81-1.02 [p = .10]). No effect was found for all other included outcomes, including mortality (OR = 1.27, 95% CI: 0.90-1.79 [p = .18]) and hospital length of stay (mean difference = 0.03 days, 95% CI -0.25 to 0.30 [p = .84). Results from subgroup analyses and meta-regression did not identify any clear effect modifiers across outcomes. The certainty of evidence (GRADE) was rated as low for most outcomes. CONCLUSIONS: In adults undergoing general anesthesia for non-cardiac surgery, a high FiO2 did not improve outcomes including surgical site infections, length of stay, or mortality. However, the certainty of the evidence was assessed as low.

Goal-directed haemodynamic therapy during general anaesthesia for noncardiac surgery: a systematic review and meta-analysis.

BACKGROUND: During general anaesthesia for noncardiac surgery, there remain knowledge gaps regarding the effect of goal-directed haemodynamic therapy on patient-centred outcomes. METHODS: Included clinical trials investigated goal-directed haemodynamic therapy during general anaesthesia in adults undergoing noncardiac surgery and reported at least one patient-centred postoperative outcome. PubMed and Embase were searched for relevant articles on March 8, 2021. Two investigators performed abstract screening, full-text review, data extraction, and bias assessment. The primary outcomes were mortality and hospital length of stay, whereas 15 postoperative complications were included based on availability. From a main pool of comparable trials, meta-analyses were performed on trials with homogenous outcome definitions. Certainty of evidence was evaluated using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). RESULTS: The main pool consisted of 76 trials with intermediate risk of bias for most outcomes. Overall, goal-directed haemodynamic therapy might reduce mortality (odds ratio=0.84; 95% confidence interval [CI], 0.64 to 1.09) and shorten length of stay (mean difference=-0.72 days; 95% CI, -1.10 to -0.35) but with low certainty in the evidence. For both outcomes, larger effects favouring goal-directed haemodynamic therapy were seen in abdominal surgery, very high-risk surgery, and using targets based on preload variation by the respiratory cycle. However, formal tests for subgroup differences were not statistically significant. Goal-directed haemodynamic therapy decreased risk of several postoperative outcomes, but only infectious outcomes and anastomotic leakage reached moderate certainty of evidence. CONCLUSIONS: Goal-directed haemodynamic therapy during general anaesthesia might decrease mortality, hospital length of stay, and several postoperative complications. Only infectious postoperative complications and anastomotic leakage reached moderate certainty in the evidence.

Factors associated with shockable versus non-shockable rhythms in patients with in-hospital cardiac arrest.

AIM: To identify factors associated with the initial rhythm in patients with in-hospital cardiac arrest and to assess whether potential differences in outcomes based on the initial rhythm can be explained by patient and event characteristics. METHODS: Adult patients (≥18 years old) with in-hospital cardiac arrest in 2017 and 2018 were included from the Danish In-Hospital Cardiac Arrest Registry (DANARREST). We used population-based registries to obtain data on comorbidities, cardiac procedures, and medications. Unadjusted and adjusted risk ratios (RRs) for initial rhythm, return of spontaneous circulation (ROSC), and survival were estimated in separate models including an incremental number of prespecified variables. RESULTS: A total of 3422 patients with in-hospital cardiac arrest were included, of which 639 (19%) had an initial shockable rhythm. Monitored cardiac arrest, witnessed cardiac arrest, and specific cardiac diseases (i.e. ischemic heart disease, dysrhythmias, and valvular heart disease) were associated with initial shockable rhythm. Conversely, higher age, female sex, and specific non-cardiovascular comorbidities (e.g. overweight and obesity, renal disease, and pulmonary cancer) were associated with an initial non-shockable rhythm. Initial shockable rhythm remained strongly associated with increased ROSC (RR = 1.63, 95%CI 1.51-1.76), 30-day survival (RR = 2.31, 95%CI 2.02-2.64), and 1-year survival (RR = 2.36, 95%CI 2.02-2.76) compared to initial non-shockable rhythm in the adjusted analyses. CONCLUSION: In this study, specific patient and cardiac arrest characteristics were associated with initial rhythm in patients with in-hospital cardiac arrest. However, differences in patient and cardiac arrest characteristics did not fully explain the association with survival for initial shockable rhythm compared to a non-shockable rhythm.

Ubiquinol (Reduced Coenzyme Q10) and Cellular Oxygen Consumption in Patients Undergoing Coronary Artery Bypass Grafting.

Ubiquinol is a fundamental component of cellular metabolism. Low ubiquinol levels have been associated with mortality. This was a substudy of a randomized trial in patients undergoing coronary artery bypass grafting. We drew blood before and after surgery. Ubiquinol or placebo was added to peripheral blood mononuclear cells for oxygen consumption (OCR) measurements. In vivo ubiquinol levels were lower postsurgery compared to presurgery (0.16 µmol/L [quartiles: 0.02-0.39], P = .01), although the difference disappeared when adjusting for hemoglobin levels (P = .30). There was no difference in presurgical basal (1.0 mL/min/mg [95% confidence interval [CI]: -0.9 to 2.2], P = .08) and maximal (0.5 mL/min/mg [95% CI: -4.3 to 7.3], P = .56) OCR in cells receiving ubiquinol or placebo. There was a difference in postsurgical basal (1.1 mL/min/mg [95% CI: 0.9-1.6], P < .001) and maximal (4.2 mL/min/mg [95% CI: 0.3-7.0], P = .01) OCR between the groups. We found no association between ubiquinol and OCR levels (all P > .05).

Cytochrome c in patients undergoing coronary artery bypass grafting: A post hoc analysis of a randomized trial.

PURPOSE: To establish whether plasma cytochrome c is detectable in patients undergoing cardiac surgery, whether cytochrome c levels are associated with lactate/inflammatory markers/cellular oxygen consumption, and whether cytochrome c levels are associated with clinical outcomes. MATERIALS AND METHODS: This was an observational sub-study of a randomized trial comparing thiamine to placebo in patients undergoing coronary artery bypass grafting. Patients had blood drawn before, after, and again 6h after surgery. Cytochrome c, inflammatory markers, and cellular oxygen consumption were measured. RESULTS: 64 patients were included. Cytochrome c was detectable in 63 (98%) patients at baseline with a median cytochrome c level of 0.18ng/mL (quartiles: 0.13, 0.55). There was no difference from baseline level to post-surgical level (0.19ng/mL [0.09, 0.51], p=0.36) or between post-surgical level and 6-hour post-surgical level (0.17ng/mL [0.10, 0.57], p=0.61). There was no difference between the thiamine and placebo groups' change in cytochrome c levels from baseline to after surgery (p=0.22). Cytochrome c levels were not associated with lactate, inflammatory markers, cellular oxygen consumption, or clinical outcomes. CONCLUSIONS: Cytochrome c levels did not increase after cardiac surgery and was not associated with the degree of inflammation or clinical outcomes.

Outcomes in variceal hemorrhage following the use of a balloon tamponade device.

BACKGROUND: Variceal hemorrhage is associated with high morbidity and mortality. A balloon tamponade device (BTD), such as the Sengstaken-Blakemore or Minnesota tube, may be used in cases of variceal hemorrhage. While these devices may be effective at controlling acute bleeding, the effect on patient outcomes remains less clear. We sought to describe the number of patients with variceal hemorrhage and a BTD who survive to discharge, survive to one-year, and develop complications related to a BTD. METHODS: In this retrospective study, we identified patients at a single, tertiary care center who underwent placement of a BTD for upper gastrointestinal hemorrhage between 2003 and 2014. Patient characteristics and outcomes were summarized using descriptive statistics. RESULTS: 34 patients with a BTD were identified. Median age was 57.5 (IQR 47-63) and 76% (26/34) were male. Approximately 59% (20/34) of patients survived to discharge, and 41% (13/32) were alive after one year. Two patients were lost to follow-up. Of those surviving to discharge, 95% (19/20) had undergone transjugular intrahepatic portosystemic shunt (TIPS), while 36% (5/14) of patients who did not survive to discharge had TIPS (p<0.01). One complication, an esophageal perforation, was identified and managed conservatively. CONCLUSION: In this cohort of patients undergoing BTD placement for variceal hemorrhage, approximately 59% of patients were alive at discharge and 41% were alive after one year. Placement of a BTD as a temporizing measure in the management of acute variceal hemorrhage may be helpful, particularly when utilized as a bridge to more definitive therapy.

Thiamine as an adjunctive therapy in cardiac surgery: a randomized, double-blind, placebo-controlled, phase II trial.

BACKGROUND: Thiamine is a vitamin that is essential for adequate aerobic metabolism. The objective of this study was to determine if thiamine administration prior to coronary artery bypass grafting would decrease post-operative lactate levels as a measure of increased aerobic metabolism. METHODS: We performed a randomized, double-blind, placebo-controlled trial of patients undergoing coronary artery bypass grafting. Patients were randomized to receive either intravenous thiamine (200 mg) or placebo both immediately before and again after the surgery. Our primary endpoint was post-operative lactate levels. Additional endpoints included pyruvate dehydrogenase activity, global and cellular oxygen consumption, post-operative complications, and hospital and intensive care unit length of stay. RESULTS: Sixty-four patients were included. Thiamine levels were significantly higher in the thiamine group as compared to the placebo group immediately after surgery (1200 [683, 1200] nmol/L vs. 9 [8, 13] nmol/L, p < 0.001). There was no difference between the groups in the primary endpoint of lactate levels immediately after the surgery (2.0 [1.5, 2.6] mmol/L vs. 2.0 [1.7, 2.4], p = 0.75). Relative pyruvate dehydrogenase activity was lower immediately after the surgery in the thiamine group as compared to the placebo group (15% [11, 37] vs. 28% [15, 84], p = 0.02). Patients receiving thiamine had higher post-operative global oxygen consumption 1 hour after the surgery (difference: 0.37 mL/min/kg [95% CI: 0.03, 0.71], p = 0.03) as well as cellular oxygen consumption. We found no differences in clinical outcomes. CONCLUSIONS: There were no differences in post-operative lactate levels or clinical outcomes between patients receiving thiamine or placebo. Post-operative oxygen consumption was significantly increased among patients receiving thiamine. TRIAL REGISTRATION: clinicaltrials.gov NCT02322892, December 14, 2014.

Cytochrome C in Patients with Septic Shock.

PURPOSE: Cytochrome c is an essential component of the electron transport chain, and circulating cytochrome c might be an indicator of mitochondrial injury. The objective of this study was to determine whether cytochrome c levels are elevated in septic patients, whether there is an association between cytochrome c levels and lactate/inflammatory markers, and whether elevated levels of cytochrome c are associated with poor outcomes. METHODS: This was a single-center, prospective, observational, pilot study within a randomized, placebo-controlled trial. We enrolled adult patients in septic shock and with an elevated lactate (>3 mmol/L). Blood was collected at enrollment and at 12 and 24  h thereafter. Cytochrome c was measured in plasma using an electrochemiluminescence immunoassay. RESULTS: We included 77 patients. Plasma cytochrome c levels were significantly higher in septic patients than in healthy controls (0.70  ng/mL [quartiles: 0.06, 1.99] vs. 0.19  ng/mL [quartiles: 0.03, 1.32], P = 0.008). Cytochrome c levels at enrollment were positively correlated with lactate levels (r(s) = 0.40, P < 0.001) but not with inflammatory markers. Patients who died before hospital discharge had significantly higher cytochrome c levels than survivors (0.99  ng/mL [quartiles: 0.36, 4.09] vs. 0.58  ng/mL [quartiles: 0.03, 1.64], P = 0.01). When analyzed over time, the difference between survivors and nonsurvivors remained significant (P < 0.001). CONCLUSIONS: Cytochrome c levels are higher in septic patients than in controls. In unadjusted analysis, septic nonsurvivors had higher cytochrome c levels than survivors.

Postoperative Lactate Levels and Hospital Length of Stay After Cardiac Surgery.

OBJECTIVES: The objective of this study was to characterize the association between lactate levels and hospital length of stay (LOS) after cardiac surgery. DESIGN: A retrospective study using prospectively collected data from the Society of Thoracic Surgeons adult cardiac surgery database. SETTING: A tertiary-care hospital. PARTICIPANTS: Patients in the database who presented for major cardiac surgery between 2002 and 2014 and whose lactate level was measured within 3 hours after skin closure. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The authors performed multivariable linear regression with adjustment for more than 30 variables to assess the association between postoperative lactate levels and hospital LOS. The study included 1,208 patients whose median LOS was 6 days (quartiles: 5, 9). Median LOS in the low-, moderate-, and high-lactate groups was 5 days (quartiles: 4, 7), 6 days (quartiles: 5, 9) and 9 days (quartiles: 6, 17), respectively; p<0.001. In multivariable analysis, patients with a moderate lactate level had a 1.08 times (95% CI: 1.00-1.17; p = 0.04) longer LOS compared with those with a low lactate level. Patients with a high lactate level had a 1.12 times (95% CI: 1.00-1.26; p = 0.04) longer LOS compared with those with a low lactate level. Lactate levels also were associated with intensive care unit LOS and nonsurgical postoperative complications. CONCLUSIONS: Postoperative lactate levels are associated with increased hospital LOS for patients undergoing major cardiac surgery.

Estimating duration of central venous catheter at time of insertion: Clinician judgment and clinical predictors.

PURPOSE: The aim of this study was to investigate whether clinicians can estimate the length of time a central venous catheter (CVC) will remain in place and to identify variables that may predict CVC duration. MATERIALS AND METHODS: We conducted a prospective study of patients admitted to the intensive care unit over a 1-year period. Clinicians estimated the anticipated CVC duration at time of insertion. We collected demographics, medical history, type of intensive care unit, anatomical site of CVC placement, vital signs, laboratory values, Sequential Organ Failure Assessment score, mechanical ventilation, and use of vasopressors. Pearson correlation coefficient was used to assess the correlation between estimated and actual CVC time. We performed multivariable logistic regression to identify predictors of long duration (>5 days). RESULTS: We enrolled 200 patients; median age was 65 years (quartiles 52, 75); 91 (46%) were female; and mortality was 24%. Correlation between estimated and actual CVC time was low (r=0.26; r2=0.07; P<.001). Mechanical ventilation (odds ratio, 2.20; 95% confidence interval, 1.22-3.97; P=.009) at time of insertion and a medical history of cancer (odds ratio, 0.35; 95% confidence interval, 0.16-0.75; P=.007) were significantly associated with long duration. CONCLUSION: Our results suggest a low correlation between clinician prediction and actual CVC duration. We did not find any strong predictors of long CVC duration identifiable at the time of insertion.