AcumenTM hypotension prediction index guidance for prevention and treatment of hypotension in noncardiac surgery: a prospective, single-arm, multicenter trial.

BACKGROUND: Intraoperative hypotension is common during noncardiac surgery and is associated with postoperative myocardial infarction, acute kidney injury, stroke, and severe infection. The Hypotension Prediction Index software is an algorithm based on arterial waveform analysis that alerts clinicians of the patient's likelihood of experiencing a future hypotensive event, defined as mean arterial pressure < 65 mmHg for at least 1 min. METHODS: Two analyses included (1) a prospective, single-arm trial, with continuous blood pressure measurements from study monitors, compared to a historical comparison cohort. (2) A post hoc analysis of a subset of trial participants versus a propensity score-weighted contemporaneous comparison group, using external data from the Multicenter Perioperative Outcomes Group (MPOG). The trial included 485 subjects in 11 sites; 406 were in the final effectiveness analysis. The post hoc analysis included 457 trial participants and 15,796 comparison patients. Patients were eligible if aged 18 years or older, American Society of Anesthesiologists (ASA) physical status 3 or 4, and scheduled for moderate- to high-risk noncardiac surgery expected to last at least 3 h. MEASUREMENTS: minutes of mean arterial pressure (MAP) below 65 mmHg and area under MAP < 65 mmHg. RESULTS: Analysis 1: Trial subjects (n = 406) experienced a mean of 9 ± 13 min of MAP below 65 mmHg, compared with the MPOG historical control mean of 25 ± 41 min, a 65% reduction (p < 0.001). Subjects with at least one episode of hypotension (n = 293) had a mean of 12 ± 14 min of MAP below 65 mmHg compared with the MPOG historical control mean of 28 ± 43 min, a 58% reduction (p< 0.001). Analysis 2: In the post hoc inverse probability treatment weighting model, patients in the trial demonstrated a 35% reduction in minutes of hypotension compared to a contemporaneous comparison group [exponentiated coefficient: - 0.35 (95%CI - 0.43, - 0.27); p < 0.001]. CONCLUSIONS: The use of prediction software for blood pressure management was associated with a clinically meaningful reduction in the duration of intraoperative hypotension. Further studies must investigate whether predictive algorithms to prevent hypotension can reduce adverse outcomes. TRIAL REGISTRATION: Clinical trial number: NCT03805217. Registry URL: https://clinicaltrials.gov/ct2/show/NCT03805217 . Principal investigator: Xiaodong Bao, MD, PhD. Date of registration: January 15, 2019.

Use of Transesophageal Echocardiography for Liver Transplantation: A Global Comparison of Practice From the ILTS, SATA, and LICAGE.

BACKGROUND: Anesthesiologists frequently use intraoperative transesophageal echocardiography (TEE) to aid in the diagnosis and management of hemodynamic problems during liver transplantation (LT). Although the use of TEE in US centers continues to increase, data regarding international use are lacking. METHODS: This prospective, global, survey-based study evaluates international experience with TEE for LT. Responses from 252 LT (105 US and 147 non-US) centers representing 1789 anesthesiologists were analyzed. RESULTS: Routine use of TEE in the United States has increased in the last 5 y (from 37% to 47%), but only 21% of non-US LT anesthesiologists use TEE routinely. Lack of training (44% US versus 70% non-US) and equipment (9% non-US, versus 34% US) were cited as obstacles. Most survey participants preferred not to perform a complete cardiac examination but rather use only 6 of 11 basic views. Although non-US LT anesthesiologists more frequently had additional clinical training than their US counterparts, they had less TEE experience (13% versus 44%) and less frequently, TEE certification (22% versus 35%). Most LT anesthesiologists agreed that TEE certification is essential for proficiency. Of all respondents, 89% agreed or strongly agreed that TEE provides valuable information needed for immediate clinical decision-making, and >86% agreed or strongly agreed that that information could not be derived from other sources. CONCLUSIONS: The use of TEE for LT surgery in the US LT centers is currently higher compared with non-US LT centers. This may become a standard monitoring modality during LT in the near future.

EVALUATION OF COMPONENTS OF THE EXTRACELLULAR PURINERGIC SIGNALING SYSTEM IN HUMAN SEPSIS.

ABSTRACT: Objective: Extracellular purines such as adenosine triphosphate (ATP), uridine triphosphate (UTP), and uridine diphosphate (UDP) and the ATP degradation product adenosine are biologically active signaling molecules, which accumulate at sites of metabolic stress in sepsis. They have potent immunomodulatory effects by binding to and activating P1 or adenosine and P2 receptors on the surface of leukocytes. Here we assessed the levels of extracellular purines, their receptors, metabolic enzymes, and cellular transporters in leukocytes of septic patients. Methods: Peripheral blood mononuclear cells (PBMCs), neutrophils, and plasma were isolated from blood obtained from septic patients and healthy control subjects. Ribonucleic acid was isolated from cells, and mRNA levels for purinergic receptors, enzymes, and transporters were measured. Adenosine triphosphate, UTP, UDP, and adenosine levels were evaluated in plasma. Results: Adenosine triphosphate levels were lower in septic patients than in healthy individuals, and levels of the other purines were comparable between the two groups. Levels of P1 and P2 receptors did not differ between the two patient groups. mRNA levels of ectonucleoside triphosphate diphosphohydrolase (NTPDase) 1 or CD39 increased, whereas those of NTPDase2, 3, and 8 decreased in PBMCs of septic patients when compared with healthy controls. CD73 mRNA was lower in PBMCs of septic than in healthy individuals. Equilibrative nucleoside transporter (ENT) 1 mRNA concentrations were higher and ENT2, 3, and 4 mRNA concentrations were lower in PBMCs of septic subjects when compared with healthy subjects. Concentrative nucleoside transporter (CNT) 1 mRNA levels were higher in PBMCs of septic versus healthy subjects, whereas the mRNA levels of CNT2, 3, and 4 did not differ. We failed to detect differences in mRNA levels of purinergic receptors, enzymes, and transporters in neutrophils of septic versus healthy subjects. Conclusion: Because CD39 degrades ATP to adenosine monophosphate (AMP), the lower ATP levels in septic individuals may be the result of increased CD39 expression. This increased degradation of ATP did not lead to increased adenosine levels, which may be explained by the decreased expression of CD73, which converts AMP to adenosine. Altogether, our results demonstrate differential regulation of components of the purinergic system in PBMCs during human sepsis.

Surgeon-Delivered Nerve Block for Reduction of Perioperative Pain and Opioid Use After Lumbosacral Spine Surgery.

This cohort study compares postoperative pain scores, opioid use, and length of hospital stay among adults undergoing noninstrumented lumbosacral surgery who received x-ray­guided dorsal ramus block vs those who did not.

A2A adenosine receptor activation prevents neutrophil aging and promotes polarization from N1 towards N2 phenotype.

Extracellular adenosine is a biologically active signaling molecule that accumulates at sites of metabolic stress in sepsis. Extracellular adenosine has potent immunosuppressive effects by binding to and activating G protein-coupled A2A adenosine receptors (A2AARs) on the surface of neutrophils. A2AAR signaling reproduces many of the phenotypic changes in neutrophils that are characteristic of sepsis, including decreased degranulation, impaired chemotaxis, and diminished ability to ingest and kill bacteria. We hypothesized that A2AARs also suppress neutrophil aging, which precedes cell death, and N1 to N2 polarization. Using human neutrophils isolated from healthy subjects, we demonstrate that A2AAR stimulation slows neutrophil aging, suppresses cell death, and promotes the polarization of neutrophils from an N1 to N2 phenotype. Using genetic knockout and pharmacological blockade, we confirmed that A2AARs decrease neutrophil aging in murine sepsis induced by cecal ligation and puncture. A2AARs expression is increased in neutrophils from septic patients compared to healthy subject but A2AAR expression fails to correlate with aging or N1/N2 polarization. Our data reveals that A2AARs regulate neutrophil aging in healthy but not septic neutrophils.

Perioperative fluid management and outcomes in adult deceased donor liver transplantation - A systematic review of the literature and expert panel recommendations.

BACKGROUND: Fluid management practices during and after liver transplantation vary widely among centers despite better understanding of the pathophysiology of end-stage liver disease and of the effects of commonly used fluids. This reflects a lack of high quality trials in this setting, but also provides a rationale for both systematic review of all relevant studies in liver recipients and evaluation of new evidence from closely related domains, including hepatology, non-transplant abdominal surgery, and critical care. OBJECTIVES: To develop evidence-based recommendations for perioperative fluid management to optimize immediate and short-term outcomes following liver transplantation. DATA SOURCES: Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central. METHODS: Systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel. Studies included those evaluating the following postoperative outcomes: acute kidney injury, respiratory complications, operative blood loss/red cell units required, and intensive care length of stay. PROSPERO protocol ID: CRD42021241392 RESULTS: Following expert panel review, 18 of 1624 screened studies met eligibility criteria for inclusion in the final quantitative synthesis. These included six single center RCTs, 11 single center observational studies, and one observational study comparing centers with different fluid management techniques. Definitions of interventions and outcomes varied between studies. Recommendations are therefore based substantially on expert opinion and evidence from other clinical settings. CONCLUSIONS: A moderately restrictive or "replacement only" fluid regime is recommended, especially during the dissection phase of the transplant procedure. Sustained hypervolemia, based on absence of fluid responsiveness, elevated filling pressures and/or echocardiographic findings, should be avoided (Quality of Evidence: Moderate | Grade of Recommendation: Weak for restrictive fluid regime. Strong for avoidance of hypervolemia). Mean Arterial Pressure (MAP) should be maintained at >60-65 mmHg in all cases (Quality of Evidence: Low | Grade of Recommendation: Strong). There is insufficient evidence in this population to support preferential use of any specific colloid or crystalloid for routine volume replacement. However, we recommend against the use of 130/.4 HES given the high incidence of AKI in this population.

Spinal Cord Protection for Thoracoabdominal Aortic Surgery.

Open and endovascular repairs of the descending thoracic and thoracoabdominal aorta are associated with a substantial risk of spinal cord injury, namely paraplegia. Endovascular repairs seem to have a lower incidence of spinal cord injury, but there have been no randomized trials comparing outcomes of open and endovascular repairs. Paraplegia occurs when collateral blood supply to the anterior spinal artery is impaired. The risk of spinal cord injury can be mitigated with perioperative protocols that include drainage of cerebrospinal fluid, avoidance of hypotension and anemia, intraoperative neurophysiologic monitoring, and advanced surgical techniques. Drainage of cerebrospinal fluid using a spinal drain decreases the risk of spinal cord ischemia by improving spinal cord perfusion pressure. However, cerebrospinal fluid drainage has risks including neuraxial and intracranial bleeding, and these risks need to be carefully weighed against its potential benefit. This review discusses current surgical management of descending thoracic and thoracoabdominal aortic disease, incidence of and risk factors for spinal cord injury, and elements of spinal cord protection protocols that pertain to anesthesiologists, with a focus on cerebrospinal fluid drainage.

Anesthetic Resource Limitations and Adaptations in Times of Shortage: Experiences from New York Presbyterian Hospital During COVID-19.

In March 2020, the COVID-19 pandemic reached New York City, resulting in thousands of deaths over the following months. Because of the exponential spread of disease, the New York City hospital systems became rapidly overwhelmed. The Department of Anesthesiology at New York Presbyterian (NYP)-Columbia continued to offer anesthesia services for obstetrics and emergency surgery, while redirecting the rest of its staff to the expanded airway management role and the creation of the largest novel intensive care unit in the NYP system. Tremendous innovation and optimization were necessary in the face of material, physical, and staffing constraints.

Hypercoagulable viscoelastic blood clot characteristics in critically ill coronavirus disease 2019 patients and associations with thrombotic complications.

BACKGROUND: Critically ill coronavirus disease 2019 (COVID-19) patients have frequent thrombotic complications and laboratory evidence of hypercoagulability. The relationship of coagulation tests and thrombosis requires investigation to identify best diagnostic and treatment approaches. We assessed for hypercoagulable characteristics in critically ill COVID-19 patients using rotational thromboelastometry (ROTEM) and explored relationships of D-dimer and ROTEM measurements with thrombotic complications. METHODS: Critically ill adult COVID-19 patients receiving ROTEM testing between March and April 2020 were analyzed. Patients receiving therapeutic anticoagulation before ROTEM were excluded. Rotational thromboelastometry measurements from COVID-19 patients were compared with non-COVID-19 patients matched by age, sex, and body mass index. Intergroup differences in ROTEM measurements were assessed using t tests. Correlations of D-dimer levels to ROTEM measurements were assessed in COVID-19 patients who had available concurrent testing. Intergroup differences of D-dimer and ROTEM measurements were explored in COVID-19 patients with and without thrombosis. RESULTS: Of 30 COVID-19 patients receiving ROTEM, we identified hypercoagulability from elevated fibrinogen compared with non-COVID-19 patients (fibrinogen assay maximum clot firmness [MCF], 47 ± 13 mm vs. 20 ± 7 mm; mean intergroup difference, 27.4 mm; 95% confidence interval [CI], 22.1-32.7 mm; p < 0.0001). In our COVID-19 cohort, thrombotic complications were identified in 33%. In COVID-19 patients developing thrombotic complications, we identified higher D-dimer levels (17.5 ± 4.3 µg/mL vs. 8.0 ± 6.3 µg/mL; mean difference, 9.5 µg/mL; 95% CI, 13.9-5.1; p < 0.0001) but lower fibrinogen assay MCF (39.7 ± 10.8 mm vs. 50.1 ± 12.0 mm; mean difference, -11.2 mm; 95% CI, -2.1 to -20.2; p = 0.02) compared with patients without thrombosis. We identified negative correlations of D-dimer levels and ROTEM MCF in these patients (r = -0.61; p = 0.001). CONCLUSION: We identified elevated D-dimer levels and hypercoagulable blood clot characteristics from increased fibrinogen on ROTEM testing in critically ill COVID-19 patients. However, we identified lower, albeit still hypercoagulable, ROTEM measurements of fibrinogen in COVID-19 patients with thrombotic complications compared with those without. Further work is required to externally validate these findings and to investigate the mechanistic drivers for these relationships to identify best diagnostic and treatment approaches for these patients. LEVEL OF EVIDENCE: Epidemiologic, level IV.

When Is a Critically Ill Cirrhotic Patient Too Sick to Transplant? Development of Consensus Criteria by a Multidisciplinary Panel of 35 International Experts.

BACKGROUND: Critically ill cirrhotic patients are increasingly transplanted, but there is no consensus about futile liver transplantation (LT). Therefore, the decision to delay or deny LT is often extensively debated. These debates arise from different opinions of futility among transplant team members. This study aims to achieve a multinational and multidisciplinary consensus on the definition of futility in LT and to develop well-articulated criteria for not proceeding with LT due to futility. METHODS: Thirty-five international experts from anesthesiology/intensive care, hepatology, and transplant surgery were surveyed using the Delphi method. More than 70% of similar answers to a question were necessary to define agreement. RESULTS: The panel recommended patient and graft survival at 1 year after LT to define futility. Severe frailty and persistent fever or <72 hours of appropriate antimicrobial therapy in case of ongoing sepsis were considered reasons to delay LT. A simple assessment of the number of organs failing was considered the most appropriate way to decide whether LT should be delayed or denied, with respiratory, circulatory and metabolic failures having the most influence in this decision. The thresholds of severity of organ failures contraindicating LT for which a consensus was achieved were a Pao2/FiO2 ratio<150 mm Hg, a norepinephrine dose >1 µg/kg per minute and a serum lactate level >9 mmol/L. CONCLUSIONS: Our expert panel provides a consensus on the definition of futile LT and on specific criteria for postponing or denying LT. A framework that may facilitate the decision if a patient is too sick for transplant is presented.

Acute kidney injury after cardiac surgery: A comparison of different definitions.

AIM: Acute kidney injury (AKI) after cardiac surgery increases morbidity and mortality. Different definitions for AKI have been used such as Acute Kidney Injury Network (AKIN), Kidney Disease: Improving Global Outcomes (KDIGO) or risk, injury, failure, loss, end-stage kidney disease (RIFLE). The aim of this study is to determine the best definition of AKI after cardiac surgery with the largest impact on the outcome. METHODS: This retrospective study of cardiac surgery patients compared the incidence and effect on outcome (90-day and 1-year mortality) of different definitions of AKI: RIFLE, AKIN and KDIGO. Additionally, we defined transient AKI (increase in serum creatinine that resolved in <72 hours), sustained (increase in serum creatinine within 48 hours that remained for >72 hours), and late (increase in serum creatinine after 48 hours). RESULTS: Of the included 1551 patients, 410 patients developed AKI defined by AKIN criteria, 449 defined by KDIGO and 217 defined by RIFLE-Risk criteria. Hundred and nine patients developed transient AKI (6.9%), 183 patients had sustained AKI (11.6%), and 106 patients had late AKI (6.7%). The best definition with the highest positive likelihood ratio was RIFLE-Risk (positive likelihood ratio = 2.32) followed by "sustained AKI" (positive likelihood ratio = 2.27). AKI defined by AKIN criteria missed all 80 patients with late AKI and 39 patients with KDIGO AKI. CONCLUSION: Risk, injury, failure, loss, end-stage kidney disease-risk was the best definition of AKI as determined by the ability to predict short-term mortality. A substantial number of patients developed AKI only after 48 hours, and these were missed when using AKIN criteria. AKIN criteria are not sensitive enough to capture all episodes of AKI in this population.

Pulmonary alveolar hemorrhage in a patient with a temporary external ventricular assist device and extracorporeal membrane oxygenation.

Mechanical circulatory support is increasingly used and may bring about unique challenges. Most support systems require systemic anticoagulation and the need for anticoagulation must be balanced against the increased risk for bleeding. We report the case of a young man awaiting heart retransplantation, who was supported with a temporary extracorporeal ventricular assist device with the addition of an oxygenator. He developed hemoptysis that forced the cessation of anticoagulation exposing to increased thromboembolic risk. We discuss this distinct clinical scenario with no clearly defined solution and explore the risks and benefits of the different treatment options.

Early Postoperative Neutrophil Gelatinase-Associated Lipocalin Predicts the Development of Chronic Kidney Disease After Liver Transplantation.

BACKGROUND: Urinary neutrophil gelatinase-associated lipocalin (uNGAL)-associated acute kidney injury is common after liver transplantation (LT), but whether early acute kidney injury predicts chronic kidney disease (CKD) and mortality remains uncertain. METHODS: Adults with LT from 2008 to 2010 in a previously published prospective cohort evaluating serial uNGAL pre- and post-LT were retrospectively assessed to evaluate uNGAL as a predictor of long-term outcomes post-LT. The primary outcomes were post-LT CKD, defined as Modification of Diet in Renal Disease estimated glomerular filtration rate less than 60 mL/min per 1.73 m for 3 continuous months, and death. RESULTS: uNGAL at 24 hours postreperfusion was significantly higher among patients who developed CKD. Multivariable modeling for the development of CKD demonstrated that uNGAL at 24-hours postreperfusion, 24 hours post-LT renal function, initial calcineurin inhibitor, and age were independent predictors of the development of CKD at in this cohort with long-term follow-up post-LT. Further, this association was stronger in those with preserved pre-LT renal function, a population where renal outcomes are often difficult to predict. CONCLUSIONS: We propose that perioperative uNGAL may identify patients at risk for CKD and allow for targeted early implementation of renal-sparing strategies.

Urinary neutrophil gelatinase-associated lipocalin (NGAL) distinguishes sustained from transient acute kidney injury after general surgery.

BACKGROUND: This prospective study tests the hypothesis that after general surgery urinary NGAL can distinguish between sustained acute kidney injury (AKI), typical of nephron damage, from transient AKI, commonly seen with hemodynamic variation and prerenal azotemia. METHODS: Urine was collected in 510 patients within 2-3 hr after general surgery and urinary NGAL was determined using ELISA. Patients who met AKIN Stage 1 criteria of AKI were sub-classified into those with sustained AKI (serum creatinine elevation for more than 3 days), and those with transient AKI (serum creatinine elevation for less 3 days). RESULTS: Seventeen of 510 patients (3.3%) met the Stage 1 AKIN criteria within 48 hrs of surgery. Elevations in serum creatinine were sustained in 9 and transient in 8 patients. Urinary NGAL was significantly elevated only in patients with sustained AKI (204.8+/-411.9 ng/dL); patients with transient AKI had urinary NGAL that was indistinguishable from patients who did not meet AKIN criteria at all (30.8 ±36.5 ng/dL vs. 31.9 ±113 ng/dL). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve of urinary NGAL to predict sustained AKI was 0.85 [CI (95%): 0.773 to 0.929, p<0.001]. CONCLUSIONS: Urinary NGAL levels measured 2-3 hr after surgery were able to distinguish the kinetics of creatinine (sustained AKI vs transient AKI) over the subsequent week. Transient AKI is an easily reversible state that is likely not associated with substantial tubular injury and therefore NGAL release. Using AKIN criteria, both transient and sustained AKI are classified as AKI even though our data demonstrates that they are possibly different entities.

Rotational thromboelastometry predicts thromboembolic complications after major non-cardiac surgery.

INTRODUCTION: Thromboembolic complications contribute substantially to perioperative morbidity and mortality. Routine laboratory tests do not detect patients with acquired or congenital hypercoagulability who may be at increased risk of perioperative thromboembolism. Rotational thromboelastometry (ROTEM) is a digitized modification of conventional thromboelastography that is stable and technically easy to use. We designed a prospective observational study to evaluate whether preoperative ROTEM can identify patients at increased risk for postoperative thromboembolic complications after major non-cardiac surgery. METHODS: Preoperative ROTEM analysis using extrinsic rotational thromboelastometry (EXTEM), intrinsic rotational thromboelastometry (INTEM), and fibrinogen rotational thromboelastometry (FIBTEM) activators was performed on 313 patients undergoing major non-cardiac surgery. Patients' medical records were reviewed after discharge for results of standard coagulation studies - partial thromboplastin time (PTT), international normalized ratio (INR), platelet count - and evidence of thromboembolic complications during their hospital stay. A thromboembolic complication was defined as a new arterial or deep venous thrombosis, catheter thrombosis, or pulmonary embolism diagnosed by ultrasound or spiral chest computed tomography. RESULTS: Ten patients developed postoperative thromboembolic complications, of whom 9 had received standard prophylaxis with subcutaneous enoxaparin or heparin. There was no indication of by PTT, INR, or platelet count. Preoperative EXTEM and INTEM activators that assess fibrin clot formation and platelet interaction indicated that these patients had significantly lower clot formation time (CFT) and significantly higher alpha angle (α) and maximum clot firmness (MCF), compared to patients without thromboembolic complications. There was no significant difference for any parameter using FIBTEM activator, which excludes platelet interaction. Receiver operating characteristic (ROC) curves were constructed for these variables. INTEM clot firmness at 10 min (A10) was the best predictor of thromboembolic complications, with an ROC area under the curve of 0.751. CONCLUSIONS: Our results indicate that preoperative ROTEM assays that include fibrin clot and platelet interaction may detect patients at increased risk for postoperative thromboembolic complications after major non-cardiac surgery. Future studies need to evaluate the clinical utility and cost effectiveness of preoperative ROTEM and better define the association between ROTEM values and specific hypercoagulable conditions.

Postoperative care/critical care of the transplant patient.

Critical care of the general surgical patient requires synthesis of the patient's physiology, intraoperative events, and preexisting comorbidities. Evaluating an abdominal solid-organ transplant recipient after surgery adds a new dimension to clinical decisions because the transplanted allograft has undergone its own physiologic challenges and now must adapt to a new environment. This donor-recipient interaction forms the foundation for assessment of early allograft function (EAF). The intensivist must accurately assess and support EAF within the context of the recipient's current physiology and preexisting comorbidities. Optimizing EAF is essential because allograft failure is a significant predictor of recipient morbidity and mortality.

Assessment of hepatic function, operative candidacy, and medical management after liver resection in the patient with underlying liver disease.

Liver resection in patients with underlying liver disease remains a formidable challenge. It requires adequate patient selection, a precise surgical plan, and avoidance of additional ischemic insults during surgery. Precise estimation of the residual liver volume using computed tomography or magnetic resonance imaging and computer-assisted volumetry allows the calculation of residual to total liver volume (RLV/TLV) ratios. Although RLV/TLV ratios over 20 to 25% are considered sufficient in healthy livers, patients with cirrhosis may only tolerate resections that result in RLV/TLV ratios over 40% and higher. Conventional laboratory tests may not be able to sufficiently predict liver reserve after resection. Dynamic tests such as indocyanine green clearance have been used to assess residual liver function and assist in deciding about operability of patients with underlying liver disease undergoing extensive resections. Intraoperative management should focus on avoiding blood loss and ischemic injury to the liver. Low central venous pressure may reduce blood loss and is recommended if tolerated without impeding renal perfusion. Portal vein and hepatic artery occlusion during resection can reduce blood loss, but will cause ischemic insult to the liver that may jeopardize residual liver function and induce postoperative hepatic failure. When feasible, vascular occlusion should be avoided in patients with underlying liver disease. The postoperative recovery is usually fast if sufficient liver remains. However, vigilance is required to detect liver dysfunction and treat its complications.

Complex hepatectomy under total vascular exclusion of the liver: impact of ischemic preconditioning on clinical outcomes.

BACKGROUND: Hepatic inflow clamping during hepatectomy introduces ischemia-reperfusion (I/R) injury, and many authors regard the addition of caval occlusion as adding increased risk. Ischemic preconditioning (IPC) is one of the protective strategies employed to reduce I/R injury in animal experiments and limited clinical series. The aim of the present study was to determine the impact of systematic adoption of IPC in patients undergoing complex hepatectomy under total hepatic vascular exclusion (TVE) based on outcomes review. METHODS: The records of 93 patients who underwent major hepatectomy involving TVE at our center from February 1998 to December 2008 were reviewed. These patients were divided into two groups: group 1 (n = 55, TVE alone) and group 2 (n = 38, TVE with IPC). IPC was performed by portal triad clamping for 10 min followed by 3-5 min of reperfusion prior to TVE and resection. RESULTS: The two groups were comparable regarding demographics, underlying liver diseases, indications for hepatectomy, duration of TVE, and preoperative liver and kidney function tests. Overall postoperative laboratory results of liver function tests were not significantly different between the two groups. Creatinine levels and prothrombin times were not significantly different between the groups. The use of IPC had no impact on the duration of the operation, blood loss, or hospital stay. The morbidity rates were 37.5 and 34.2 %, respectively. CONCLUSIONS: Our adoption of IPC as a protective strategy against I/R injury under TVE did not affect operative or laboratory parameters and clinical outcomes when compared to continuous clamping for comparable ischemic periods.

The Surgical Procedure Assessment (SPA) score predicts intensive care unit length of stay after cardiac surgery.

OBJECTIVE: The ability to predict intensive care unit length of stay greatly facilitates triage and resource allocation for postoperative cardiac surgical patients in the intensive care unit. We developed a simple, intuitive Surgical Procedure Assessment score that integrates surgical complexity (1, low; 2, intermediate; 3, high) with patient comorbidity (A, minimal; B, substantial). We hypothesized that the Surgical Procedure Assessment score would predict intensive care unit length of stay, discriminate preoperatively between fast-track and prolonged-stay patients, and compare favorably with more complex risk scores. METHODS: After institutional review board approval, 1201 cardiac surgical patients were preoperatively assigned a Surgical Procedure Assessment score, as well as a Parsonnet, Tuman, Tu, and Cardiac Anesthesia Risk Evaluation score. We compared these scores with regard to prediction of intensive care unit length of stay, as well as their concordance in predicting intensive care unit length of stay of less than 48 hours (fast track) and more than 7 days (prolonged stay). RESULTS: Intensive care unit length of stay increased significantly with increasing Surgical Procedure Assessment scores (P < .01, Cuzick's test for trend). The lowest Surgical Procedure Assessment score (1A) predicted intensive care unit length of stay of less than 48 hours, and the higher Surgical Procedure Assessment scores (2B or 3) predicted intensive care unit length of stay of more than 7 days more accurately than the Parsonnet, Tuman, Tu and Cardiac Anesthesia Risk Evaluation scores. CONCLUSIONS: The Surgical Procedure Assessment score predicts intensive care unit length of stay better than other comparable scores. It is simple, intuitive, and easily understood by all caregivers and can preoperatively discriminate fast-track from prolonged-stay patients. It is a useful tool to facilitate intensive care unit triage.

The outcome of neutrophil gelatinase-associated lipocalin-positive subclinical acute kidney injury: a multicenter pooled analysis of prospective studies.

OBJECTIVES: The aim of this study was to test the hypothesis that, without diagnostic changes in serum creatinine, increased neutrophil gelatinase-associated lipocalin (NGAL) levels identify patients with subclinical acute kidney injury (AKI) and therefore worse prognosis. BACKGROUND: Neutrophil gelatinase-associated lipocalin detects subclinical AKI hours to days before increases in serum creatinine indicate manifest loss of renal function. METHODS: We analyzed pooled data from 2,322 critically ill patients with predominantly cardiorenal syndrome from 10 prospective observational studies of NGAL. We used the terms NGAL(-) or NGAL(+) according to study-specific NGAL cutoff for optimal AKI prediction and the terms sCREA(-) or sCREA(+) according to consensus diagnostic increases in serum creatinine defining AKI. A priori-defined outcomes included need for renal replacement therapy (primary endpoint), hospital mortality, their combination, and duration of stay in intensive care and in-hospital. RESULTS: Of study patients, 1,296 (55.8%) were NGAL(-)/sCREA(-), 445 (19.2%) were NGAL(+)/sCREA(-), 107 (4.6%) were NGAL(-)/sCREA(+), and 474 (20.4%) were NGAL(+)/sCREA(+). According to the 4 study groups, there was a stepwise increase in subsequent renal replacement therapy initiation-NGAL(-)/sCREA(-): 0.0015% versus NGAL(+)/sCREA(-): 2.5% (odds ratio: 16.4, 95% confidence interval: 3.6 to 76.9, p < 0.001), NGAL(-)/sCREA(+): 7.5%, and NGAL(+)/sCREA(+): 8.0%, respectively, hospital mortality (4.8%, 12.4%, 8.4%, 14.7%, respectively) and their combination (4-group comparisons: all p < 0.001). There was a similar and consistent progressive increase in median number of intensive care and in-hospital days with increasing biomarker positivity: NGAL(-)/sCREA(-): 4.2 and 8.8 days; NGAL(+)/sCREA(-): 7.1 and 17.0 days; NGAL(-)/sCREA(+): 6.5 and 17.8 days; NGAL(+)/sCREA(+): 9.0 and 21.9 days; 4-group comparisons: p = 0.003 and p = 0.040, respectively. Urine and plasma NGAL indicated a similar outcome pattern. CONCLUSIONS: In the absence of diagnostic increases in serum creatinine, NGAL detects patients with likely subclinical AKI who have an increased risk of adverse outcomes. The concept and definition of AKI might need re-assessment.