Intraoperative Use of Albumin in Major Noncardiac Surgery: Incidence, Variability, and Association With Outcomes.

BACKGROUND: The impact of albumin use during major surgery is unknown, and a dearth of evidence governing its use in major noncardiac surgery has long precluded its standardization in clinical guidelines. OBJECTIVE: In this study, we investigate institutional variation in albumin use among medical centers in the United States during major noncardiac surgery and explore the association of intraoperative albumin administration with important postoperative outcomes. METHODS: The study is an observational retrospective cohort analysis performed among 54 U.S. hospitals in the Multicenter Perioperative Outcomes Group and includes adult patients who underwent major noncardiac surgery under general anesthesia between January 2014 and June 2020. The primary endpoint was the incidence of albumin administration. Secondary endpoints are acute kidney injury (AKI), net-positive fluid balance, pulmonary complications, and 30-day mortality. Albumin-exposed and albumin-unexposed cases were compared within a propensity score-matched cohort to evaluate associations of albumin use with outcomes. RESULTS: Among 614,215 major surgeries, predominantly iso-oncotic albumin was administered in 15.3% of cases and featured significant inter-institutional variability in use patterns. Cases receiving intraoperative albumin involved patients of higher American Society of Anesthesiologists physical status and featured larger infused crystalloid volumes, greater blood loss, and vasopressor use. Overall, albumin was most often administered at high-volume surgery centers with academic affiliation, and within a propensity score-matched cohort (n=153,218), the use of albumin was associated with AKI (aOR 1.24, 95% CI 1.20-1.28, P <0.001), severe AKI (aOR 1.45, 95% CI 1.34-1.56, P <0.001), net-positive fluid balance (aOR 1.18, 95% CI 1.16-1.20, P <0.001), pulmonary complications (aOR 1.56, 95% CI 1.30-1.86, P <0.001), and 30-day all-cause mortality (aOR 1.37, 95% CI 1.26-1.49, P <0.001). CONCLUSIONS: Intravenous albumin is commonly administered among noncardiac surgeries with significant inter-institutional variability in use in the United States. Albumin administration was associated with an increased risk of postoperative complications.

Fluids, vasopressors, and acute kidney injury after major abdominal surgery between 2015 and 2019: a multicentre retrospective analysis.

BACKGROUND: Practice patterns related to intraoperative fluid administration and vasopressor use have potentially evolved over recent years. However, the extent of such changes and their association with perioperative outcomes, such as the development of acute kidney injury (AKI), have not been studied. METHODS: We performed a retrospective analysis of major abdominal surgeries in adults across 26 US hospitals between 2015 and 2019. The primary outcome was AKI as defined by the Kidney Disease Improving Global Outcomes definition (KDIGO) using only serum creatinine criteria. Univariable linear predictive additive models were used to describe the dose-dependent risk of AKI given fluid administration or vasopressor use. RESULTS: Over the study period, we observed a decrease in the volume of crystalloid administered, a decrease in the proportion of patients receiving more than 10 ml kg-1 h-1 of crystalloid, an increase in the amount of norepinephrine equivalents administered, and a decreased duration of hypotension. The incidence of AKI increased between 2016 and 2019. An increase of crystalloid administration from 1 to 10 ml kg-1 h-1 was associated with a 58% decreased risk of AKI. CONCLUSIONS: Despite decreased duration of hypotension during the study period, decreased fluid administration and increased vasopressor use were associated with increased incidence of AKI. Crystalloid administration below 10 ml kg-1 h-1 was associated with an increased risk of AKI. Although no causality can be concluded, these data suggest that prevention and treatment of hypotension during abdominal surgery with liberal use of vasopressors at the expense of fluid administration is associated with an increased risk of postoperative AKI.

Intraoperative red blood cell transfusion, delayed graft function, and infection after kidney transplant: an observational cohort study.

BACKGROUND: Kidney transplant patients are frequently anemic and at risk for red blood cell (RBC) transfusion. Previous studies suggest that pre-transplant RBC transfusion may improve kidney transplant outcomes; however, RBC transfusion is also associated with infection. The purpose of our study was to characterize the relationships between intraoperative RBC transfusion, delayed graft function (DGF), postoperative surgical site infection (SSI), and sepsis. METHODS: Analysis was performed on a historical cohort of adult kidney transplant patients from a single medical center during a two-year period. Crude odds ratios for DGF, superficial and deep SSI, and sepsis were calculated for transfused patients and multivariate regression was used to control for potential confounders when significant relationships were identified. RESULTS: Four hundred forty-one patients had kidney transplant during the study period; 27.0% had RBC transfusion, 38.8% had DGF, 7.0% had superficial SSI, 7.9% had deep SSI, and 1.8% had sepsis. High dose RBC transfusion was associated with improved graft function, but this was negated after adjusting for confounders (OR = 0.86, 95% CI 0.26 to 2.88). There was no association between RBC transfusion and SSI. RBC transfusion was independently associated with sepsis (OR = 8.98, 95% CI 1.52 to 53.22), but the confidence interval was wide. CONCLUSIONS: Intraoperative RBC transfusion during kidney transplant is not associated with improved allograft function or incisional SSI, but is associated with postoperative sepsis. RBCs should not be liberally transfused during kidney transplant surgery to improve graft outcomes.

The Breadth of Expandable Memory CD8+ T Cells Inversely Correlates with Residual Viral Loads in HIV Elite Controllers.

UNLABELLED: Previous studies have shown that elite controllers with minimal effector T cell responses harbor a low-frequency, readily expandable, highly functional, and broadly directed memory population. Here, we interrogated the in vivo relevance of this cell population by investigating whether the breadth of expandable memory responses is associated with the magnitude of residual viremia in individuals achieving durable suppression of HIV infection. HIV-specific memory CD8(+) T cells were expanded by using autologous epitopic and variant peptides. Viral load was measured by an ultrasensitive single-copy PCR assay. Following expansion, controllers showed a greater increase in the overall breadth of Gag responses than did untreated progressors (P = 0.01) as well as treated progressors (P = 0.0003). Nef- and Env-specific memory cells expanded poorly for all groups, and their expanded breadths were indistinguishable among groups (P = 0.9 for Nef as determined by a Kruskal-Wallis test; P = 0.6 for Env as determined by a Kruskal-Wallis test). More importantly, we show that the breadth of expandable, previously undetectable Gag-specific responses was inversely correlated with residual viral load (r = -0.6; P = 0.009). Together, these data reveal a direct link between the abundance of Gag-specific expandable memory responses and prolonged maintenance of low-level viremia. Our studies highlight a CD8(+) T cell feature that would be desirable in a vaccine-induced T cell response. IMPORTANCE: Many studies have shown that the rare ability of some individuals to control HIV infection in the absence of antiretroviral therapy appears to be heavily dependent upon special HIV-specific killer T lymphocytes that are able to inhibit viral replication. The identification of key features of these immune cells has the potential to inform rational HIV vaccine design. This study shows that a special subset of killer lymphocytes, known as central memory CD8(+) T lymphocytes, is at least partially involved in the durable control of HIV replication. HIV controllers maintain a large proportion of Gag-specific expandable memory CD8(+) T cells involved in ongoing viral suppression. These data suggest that induction of this cell subset by future HIV vaccines may be important for narrowing possible routes of rapid escape from vaccine-induced CD8(+) T cell responses.

Cold ischemia time in liver transplantation: An overview.

The standard approach to organ preservation in liver transplantation is by static cold storage and the time between the cross-clamping of a graft in a donor and its reperfusion in the recipient is defined as cold ischemia time (CIT). This simple definition reveals a multifactorial time frame that depends on donor hepatectomy time, transit time, and recipient surgery time, and is one of the most important donor-related risk factors which may influence the graft and recipient's survival. Recently, the growing demand for the use of marginal liver grafts has prompted scientific exploration to analyze ischemia time factors and develop different organ preservation strategies. This review details the CIT definition and analyzes its different factors. It also explores the most recent strategies developed to implement each timestamp of CIT and to protect the graft from ischemic injury.

Pulmonary Injury Causing a Massive Air Leak During Liver Transplantation: A Case Report and Discussion of Decision-Making.

Pulmonary injury can occur during liver transplantation in patients with prior liver surgery, infection, or hepatocellular carcinoma treatments. Compromise of gas exchange during liver transplantation mandates rapid, multidisciplinary decision-making. We present a case of lung parenchymal injury causing a massive air leak during the dissection phase of a liver transplant. An endobronchial blocker was used for emergency lung isolation. Since oxygenation and pH were stable, we proceeded with liver transplantation to minimize graft ischemic time, followed by thoracic repair. The postoperative course was notable for adequate early liver function and discharge after prolonged postoperative ventilation and tube thoracostomy drainage.

Impact of Vasodilator Administration on Survival in Patients with Sepsis: A Systematic Review and Meta-Analysis.

Rationale: Sepsis and septic shock are associated with microcirculatory dysfunction, which is believed to contribute to sepsis-induced organ failure. Vasodilators have been proposed to improve tissue perfusion in sepsis, but the overall survival impact of this strategy is unclear. Objectives: To evaluate the impact of systemic vasodilator administration in patients with sepsis and septic shock on mortality. Methods: We conducted a meta-analysis using a random effects model. Published and unpublished randomized trials in adult patients with sepsis and septic shock were included when comparing the use of systemic vasodilators against no vasodilators. The primary outcome was 28-30-day mortality, and secondary outcomes were organ function and resource use measures. Results: We included eight randomized trials (1,076 patients). In patients randomized to vasodilator arms compared with those randomized to treatment without vasodilators, the 28-30-day mortality risk ratio was 0.74 (95% confidence interval, 0.54-1.01). In a chronological cumulative meta-analysis, the association between vasodilators and survival improved over time. In a prespecified subgroup analysis in 104 patients in two randomized trials, prostacyclin analogues were associated with a decreased rate of 28-30-day mortality among patients with sepsis and septic shock (risk ratio, 0.46; 95% confidence interval, 0.25-0.85). Conclusions: In patients with sepsis and septic shock, administration of vasodilators is not associated with decreased 28-30-day mortality, but the confidence interval suggests potential benefit, and the meta-analysis might lack power. Prostacyclin appears the most promising. The results of this meta-analysis should encourage randomized trials evaluating the impact of vasodilators on mortality in sepsis.

Serendipitous Discovery of T Cell-Produced KLK1b22 as a Regulator of Systemic Metabolism.

In order to study mechanistic/mammalian target of rapamycin's role in T cell differentiation, we generated mice in which Rheb is selectively deleted in T cells (T-Rheb-/- C57BL/6J background). During these studies, we noted that T-Rheb-/- mice were consistently heavier but had improved glucose tolerance and insulin sensitivity as well as a marked increase in beige fat. Microarray analysis of Rheb-/- T cells revealed a marked increase in expression of kallikrein 1-related peptidase b22 (Klk1b22). Overexpression of KLK1b22 in vitro enhanced insulin receptor signaling, and systemic overexpression of KLK1b22 in C57BL/6J mice also enhances glucose tolerance. Although KLK1B22 expression was markedly elevated in the T-Rheb-/- T cells, we never observed any expression in wild-type T cells. Interestingly, in querying the mouse Immunologic Genome Project, we found that Klk1b22 expression was also increased in wild-type 129S1/SVLMJ and C3HEJ mice. Indeed, both strains of mice demonstrate exceptionally improved glucose tolerance. This prompted us to employ CRISPR-mediated knockout of KLK1b22 in 129S1/SVLMJ mice, which in fact led to reduced glucose tolerance. Overall, our studies reveal (to our knowledge) a novel role for KLK1b22 in regulating systemic metabolism and demonstrate the ability of T cell-derived KLK1b22 to regulate systemic metabolism. Notably, however, further studies have revealed that this is a serendipitous finding unrelated to Rheb.

Four Acid-Base Disturbances in a Critically-Ill Patient Undergoing Emergent Abdominal Surgery.

Lactic acidosis is common in critically-ill surgical patients, but not all perioperative acid-base imbalances are attributable to tissue hypoperfusion. Other causes of acid-base abnormalities can be missed when focused on acute resuscitation of a surgical pathology. This report presents the case of a 60-year-old woman with no past medical history who underwent exploratory laparotomy for umbilical hernia with incarcerated and perforated bowel whose perioperative management was complicated by four acid-base disturbances, including starvation ketosis. This case highlights the importance of early recognition of acid-base imbalances to explain concurrent medical pathology and accurately predict a patient's expected post-operative course.

Revisiting the utility of technical performance scores following tetralogy of Fallot repair.

OBJECTIVE: Although an important quality metric, current technical performance scores may not be generalizable and may omit operative factors that influence outcomes. We examined factors not included in current technical performance scores that may contribute to increased postoperative length of stay, major complications, and cost after primary repair of tetralogy of Fallot. METHODS: This is a retrospective single site study of patients younger than age 2 years with tetralogy of Fallot undergoing complete repair between 2007 and 2015. Medical record data and discharge echocardiograms were reviewed to ascertain component and composite technical performance scores. Primary outcomes included postoperative length of stay, major complications, and total hospital costs. Multivariable logistic and linear regression identified determinants of each outcome. RESULTS: Patient population (n = 115) had a median postoperative length of stay of 8 days (interquartile range, 6-10 days), and a median total cost of $71,147. Major complications occurred in 33 patients (29%) with 1 death. Technical performance scores assigned were optimum in 28 patients (25%), adequate in 59 patients (52%), and inadequate in 26 patients (23%). Neither technical performance score components nor composite scores were associated with increased postoperative length of stay. Optimum or adequate repairs versus inadequate had equal risk of a complication (P = .79), and equivalent mean total cost ($100,000 vs $187,000; P = .25). Longer cardiopulmonary bypass time per 1-minute increase (P < .01) was associated with longer postoperative length of stay and reintervention (P = .02). The need to return to bypass also increased total cost (P < .01). CONCLUSIONS: Current tetralogy of Fallot technical performance scores were not associated with selected outcomes in our postoperative population. Although returning to bypass and bypass length are not included as components in the current score, these are important factors influencing complications and resource use in our population. Revisions anticipated from a prospective trial should consider including these variables.