Prevention of Cardiac Surgery-Associated Acute Kidney Injury by Implementing the KDIGO Guidelines in High-Risk Patients Identified by Biomarkers: The PrevAKI-Multicenter Randomized Controlled Trial.

BACKGROUND: Prospective, single-center trials have shown that the implementation of the Kidney Disease: Improving Global Outcomes (KDIGO) recommendations in high-risk patients significantly reduced the development of acute kidney injury (AKI) after surgery. We sought to evaluate the feasibility of implementing a bundle of supportive measures based on the KDIGO guideline in high-risk patients undergoing cardiac surgery in a multicenter setting in preparation for a large definitive trial. METHODS: In this multicenter, multinational, randomized controlled trial, we examined the adherence to the KDIGO bundle consisting of optimization of volume status and hemodynamics, functional hemodynamic monitoring, avoidance of nephrotoxic drugs, and prevention of hyperglycemia in high-risk patients identified by the urinary biomarkers tissue inhibitor of metalloproteinases-2 [TIMP-2] and insulin growth factor-binding protein 7 [IGFBP7] after cardiac surgery. The primary end point was the adherence to the bundle protocol and was evaluated by the percentage of compliant patients with a 95% confidence interval (CI) according to Clopper-Pearson. Secondary end points included the development and severity of AKI. RESULTS: In total, 278 patients were included in the final analysis. In the intervention group, 65.4% of patients received the complete bundle as compared to 4.2% in the control group (absolute risk reduction [ARR] 61.2 [95% CI, 52.6-69.9]; P < .001). AKI rates were statistically not different in both groups (46.3% intervention versus 41.5% control group; ARR -4.8% [95% CI, -16.4 to 6.9]; P = .423). However, the occurrence of moderate and severe AKI was significantly lower in the intervention group as compared to the control group (14.0% vs 23.9%; ARR 10.0% [95% CI, 0.9-19.1]; P = .034). There were no significant effects on other specified secondary outcomes. CONCLUSIONS: Implementation of a KDIGO-derived treatment bundle is feasible in a multinational setting. Furthermore, moderate to severe AKI was significantly reduced in the intervention group.

The Relationship Between Preoperative Hemoglobin Concentration, Use of Hospital Resources, and Outcomes in Cardiac Surgery.

OBJECTIVES: Preoperative anemia is an established risk factor associated with adverse perioperative outcomes after cardiac surgery. However, limited information exists regarding the relationship between preoperative hemoglobin concentration and outcomes. The aim of this study was to investigate how outcomes are affected by preoperative hemoglobin concentration in a cohort of patients undergoing cardiac surgery. DESIGN: A retrospective, observational cohort study. SETTING: A single-center tertiary referral hospital. PARTICIPANTS: The study comprised 1,972 adult patients undergoing elective and nonelective cardiac surgery. INTERVENTIONS: The independent relationship of preoperative hemoglobin concentration was explored on blood transfusion rates, return to the operating room for bleeding and/or cardiac tamponade, postoperative intensive care unit (ICU) and in-hospital length of stay, and mortality. MEASUREMENTS AND MAIN RESULTS: The overall prevalence of anemia was 32% (629/1,972 patients). For every 1-unit increase in hemoglobin (g/dL), blood transfusion requirements were reduced by 11%, 8%, and 3% for red blood cell units, platelet pools, and fresh frozen plasma units, respectively (adjusted incident rate ratio 0.89 [95% CI 0.87-0.91], 0.92 [0.88-0.97], and 0.97 [0.96-0.99]). For each 1-unit increase in hemoglobin (g/dL), the probability (over time) of discharge from the ICU and hospital increased (adjusted hazard ratio estimates 1.04 [1.00-1.08] and 1.12 [1.12-1.16], respectively). CONCLUSIONS: A lower preoperative hemoglobin concentration resulted in increased use of hospital resources after cardiac surgery. Each g/dL unit fall in preoperative hemoglobin concentration resulted in increased blood transfusion requirements and increased postoperative ICU and hospital length of stay.

Association of plasma and urine NGAL with acute kidney injury after elective colorectal surgery: A cohort study.

BACKGROUND: Acute kidney injury (AKI) is common in surgical patients. We aimed to investigate the validity of plasma and urine neutrophil gelatinase-associated lipocalin (NGAL) in the detection of AKI and prediction of outcomes in patients undergoing major colorectal surgery. MATERIALS AND METHODS: This was a pre-specified post-hoc analysis of a randomized controlled trial comparing oesophageal doppler and Lithium dilution cardiac output monitoring in high risk patients undergoing major colorectal surgery as part of an Enhanced Recovery After Surgery protocol in a tertiary care hospital. Plasma and urine samples for NGAL measurement were taken before surgery (T1), immediately after surgery (T2), and on postoperative day 1 (T3). AKI was defined according to the KDIGO criteria. RESULTS: A total of 89 patients were included of whom 12 (13.5%) developed AKI. Plasma NGAL significantly increased from T1 to T3 in both AKI (p < 0.001) and non-AKI (p = 0.048) patients, while urine NGAL did not change over time. There were no significant differences in plasma and urine NGAL in patients with and without AKI at all time points. Postoperative day 1 urine NGAL concentrations were significantly higher in non-survivors than survivors (41.2 versus 25 ng/mL, p = 0.026). One-year mortality was significantly higher in AKI patients with a raised urine NGAL compared to AKI patients without elevated urine NGAL levels. CONCLUSIONS: Plasma and urine NGAL poorly predicted AKI post-colorectal surgery. Non-survivors had higher urine NGAL results. More research is required to explore the association between NGAL and long-term outcomes.

Increased gastric-end tidal P(CO2) gap during exercise at high altitude measured by gastric tonometry.

Using automated air gastric tonometry, the hypothesis that gastric perfusion is reduced while exercising at high altitude was explored. This prospective observational study of 5 well acclimatized healthy volunteers was performed during a medical research expedition to Chamlang base camp (5000 m), Hongu valley, Nepal. We used gastric tonometry at rest and during graded submaximal exercise. The end tidal partial pressure of carbon dioxide was subtracted from the gastric mucosal partial pressure of carbon dioxide to calculate the P(CO2) gradient, which is a marker of gastric mucosal perfusion. When compared with rest, there was no increase in the mean P(CO2) gradient at the lower work rate (0.22 vs. 0.18, p 0.10), but an increase was seen between rest and the higher work rate (0.22 vs. 0.77, p = 0.04). We conclude that exercising while at high altitude can lead to a raised P(CO2) gradient when gastric tonometry is performed, indicating reduced perfusion. This may represent reduced gastric mucosal perfusion under these conditions.

Resuscitation from hemorrhagic shock using rectally administered fluids in a wilderness environment.

We report the successful use in a wilderness environment of rectally administered oral rehydation fluid to resuscitate a patient who was in shock. The subject was a 21-year-old Nepali man who had experienced a major upper gastrointestinal hemorrhage.