Balanced forced-diuresis as a renal protective approach in cardiac surgery: Secondary outcomes of electrolyte changes.

OBJECTIVES: Forced-diuresis during cardiopulmonary bypass (CPB) can be associated with significant electrolyte shifts. This study reports on the serum electrolyte changes during balanced forced-diuresis with the RenalGuard® system (RG) during CPB. METHODS: Patients at risk of acute kidney injury (AKI)-(history of diabetes &/or anaemia, e-GFR 20-60 ml/min/1.73 m2 , anticipated CPB time >120 min, Log EuroScore >5)-were randomized to either RG (study group) or managed as per current practice (control group). RESULTS: The use of RG reduced AKI rate (10% for RG and 20.9% in control, p = .03). Mean urine output was significantly higher in the RG group during surgery (2366 ± 877 ml vs. 765 ± 549 ml, p < .001). The serum potassium levels were maintained between 3.96 and 4.97 mmol/L for the RG group and 4.02 and 5.23 mmol/L for the controls. Median potassium supplemental dose was 60 (0-220) mmol (RG group) as compared to 30 (0-190) mmol for control group over first 24 h (p < .001). On Day 1 post-op, there were no significant differences in the serum sodium, potassium, calcium, magnesium, phosphate, and chloride levels between the two groups. Otherwise, postoperative clinical recovery was also similar. CONCLUSIONS: Balanced forced-diuresis with the RG reduced AKI rates after on-pump cardiac surgery compared to controls. Although the RG group required higher doses of IV potassium replacement in the postoperative period, normal serum levels of potassium were maintained by appropriate intravenous potassium supplementation and the clinical outcomes between groups were similar.

Utility of plasma NGAL for the diagnosis of AKI following cardiac surgery requiring cardiopulmonary bypass: a systematic review and meta-analysis.

The objective of this study was to assess the diagnostic value of plasma neutrophil gelatinase-associated lipocalin (pNGAL) for the early diagnosis of acute kidney injury (AKI) in adult patients following cardiac surgery requiring cardiopulmonary bypass (CPB). Electronic databases and other resources were systematically searched for relevant studies. Risk of bias was assessed using the Quality Assessment for Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Studies were assigned to a sub-group based on the timing of the pNGAL sample in relation to the cessation of CPB. These were < 4 h, 4-8 h, 12 h or 24 h post-cessation of CPB. Summary values for sensitivity and specificity were estimated using the hierarchical summary receiver operator characteristic (ROC) curve model. A random-effects meta-analysis of each pair of sensitivity and specificity estimates from each included study was performed. In total, 3131 patients from 16 studies were included. When taken at 4-8 h following CPB, pNGAL had superior performance for the diagnosis of AKI in the defined population when compared to earlier and later time points. Prediction regions and confidence intervals, however, demonstrated significant variability in pooled estimates of sensitivity and specificity. This is likely due to population and study design heterogeneity, lack of standardisation of assays and thresholds, and inability to distinguish the different molecular forms of NGAL. In conclusion, the diagnostic utility of pNGAL in this clinical setting is inconclusive and large individual studies of representative populations of cardiac surgery patients using assays that specifically detect NGAL in its monomeric form are required.

Comparative Evaluation of Two NGAL Automated Immunoassays in Urine and Plasma.

BACKGROUND: Acute kidney injury (AKI), a frequent and serious complication of hospitalized patients, is associated with increased mortality and morbidity. Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker for the early identification of AKI. We report a comparative laboratory verification of the Abbott Diagnostics (ARCHITECT® urine NGAL) and BioPorto Diagnostics (NGAL TestTM) assays including an assessment of the Abbott assay's performance in EDTA plasma. METHODS: Intra-/interbatch imprecision, linearity, recovery, and limit of quantitation (LoQ) were assessed and an interassay comparison performed (n = 51). Between-laboratory agreement was assessed against other laboratories using the Abbott (n = 48) and BioPorto (n = 94) assays. Plasma NGAL (pNGAL) levels were measured in non-AKI patients with a range of estimated glomerular filtration rates (n = 80). RESULTS: Coefficients of variation (CVs) for intra- and interbatch imprecision were 0.7%-12.4% and 1.9%-27.5% for the BioPorto assay, respectively, and 1.4%-6.3%/3.4%-6.8%, respectively, for the Abbott assay. The BioPorto assay exhibited a higher LoQ (27.5 ng/mL vs 1.2 ng/mL). Both assays were linear over the range 5-6000 ng/mL. Recovery of recombinant NGAL was 113.1 ± 7.1% and 96.5 ± 7.8% for the Abbott and BioPorto assays, respectively. On average, the Abbott assay gave results 9.2% lower than the BioPorto assay. Mean differences of 0.2% (Abbott) and 20.2% (BioPorto) were observed in the between-laboratory comparison. In patients without AKI, pNGAL levels were inversely proportional to eGFR. CONCLUSIONS: Performance of the Abbott and BioPorto assays was similar although the latter performed less well at lower NGAL concentrations. The Abbott assay tended to yield lower results, exhibited a lower LoQ and over-recovered NGAL. Although only Conformité Européenne-marked and marketed for use in urine, the Abbott assay demonstrated equivalent performance to the BioPorto assay with EDTA plasma.

Balanced forced-diuresis compared to control as a reno-protective approach in cardiac surgery: secondary outcome of a randomized controlled trial, assessment of neutrophil gelatinase-associated lipocalin levels.

BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) is a recognised biomarker for acute kidney injury (AKI).This study investigated the impact of balanced forced-diuresis using RenalGuard® system (RG), in reducing acute kidney injury (AKI) rates and the associated NGAL levels (6-h post-CPB plasma level) post adult cardiac surgery with cardiopulmonary bypass (CPB). METHODS: Patients included in the study were at high-risk for AKI post cardiac surgery, namely history of diabetes and/or anaemia, e-GFR 20-60 ml/min/1.73 m2, Logistic EuroScore > 5, anticipated CPB time > 120 min. Patients were randomized to either RG (n = 110) or managed as per current practice (control = 110). RIFLE-defined AKI rate (based on serum creatinine level increase) within first 3 days of surgery and 6-h post CPB NGAL levels were the primary and secondary end-points. RESULTS: Pre and intra-operative characteristics between the two groups were similar (p > 0.05) including the pre-op NGAL levels, the oxygen delivery (ecDO2i) and the carbon dioxide production (ecVCO2i) during CPB. Patients in the RG group had a significantly lower post-operative RIFLE-defined AKI rate compared to control (10% (11/110) v/s 20.9% (23/110), p = 0.03). Overall, median 6-h post CPB NGAL levels in patients with AKI were significantly higher than those who did not develop AKI (211 vs 150 ng/ml, p < 0.001). Patients managed by balanced forced-diuresis had lower post-operative NGAL levels (146 vs 178 ng/ml, p = 0.09). Using previously reported NGAL cut-off level for AKI (142 ng/ml), binary logistic regression analysis confirmed a beneficial effect of the RG system, with an increased risk of AKI of 2.2 times in the control group (OR 2.2, 95% CI 1.14-4.27, p = 0.02). CONCLUSIONS: Overall, the 6-h post-CPB plasma NGAL levels were significantly higher in patients who developed AKI. Patients managed with the novel approach of balanced forced-diuresis, provided by the RenalGuard® system, had a lower AKI rate and lower NGAL levels indicating a lesser degree of renal tissue injury. Trial registration ClinicalTrials.gov website, NCT02974946, https://clinicaltrials.gov/ct2/show/NCT02974946 .

Reduction in acute kidney injury post cardiac surgery using balanced forced diuresis: a randomized, controlled trial.

OBJECTIVES: Our goal was to investigate the efficacy of balanced forced diuresis in reducing the rate of acute kidney injury (AKI) in cardiac surgical patients requiring cardiopulmonary bypass (CPB), using the RenalGuard® (RG) system. METHODS: Patients at risk of developing AKI (history of diabetes and/or anaemia; estimated glomerular filtration rate 20-60 ml/min/1.73 m2; anticipated CPB time >120 min; log EuroSCORE > 5) were randomized to the RG system group (n = 110) or managed according to current practice (control = 110). The primary end point was the development of AKI within the first 3 postoperative days as defined by the RIFLE (Risk, Injury, Failure, Loss of kidney function, End-stage renal disease) criteria. RESULTS: There were no significant differences in preoperative and intraoperative characteristics between the 2 groups. Postoperative AKI rates were significantly lower in the RG system group compared to the control group [10% (11/110) vs 20.9% (23/110); P = 0.025]. This effect persisted even after controlling for a number of potential confounders (odds ratio 2.82, 95% confidence interval 1.20-6.60; P = 0.017) when assessed by binary logistic regression analysis. The mean volumes of urine produced during surgery and within the first 24 h postoperatively were significantly higher in the RG system group (P < 0.001). There were no significant differences in the incidence of blood transfusions, atrial fibrillation and infections and in the median duration of intensive care unit stays between the groups. The number needed to treat with the RG system to prevent AKI was 9 patients (95% confidence interval 6.0-19.2). CONCLUSIONS: In patients at risk for AKI who had cardiac surgery with CPB, the RS RG system significantly reduced the incidence of AKI and can be used safely and reproducibly. Larger studies are required to confirm cost benefits. CLINICAL TRIAL REGISTRATION NUMBER: NCT02974946.

Association Between Anemia and Blood Transfusion With Long-term Mortality After Cardiac Surgery.

BACKGROUND: Preoperative anemia and red blood cell (RBC) transfusion are both associated with in-hospital mortality after cardiac surgery. The aim of this study was to investigate the interactions between preoperative anemia and RBC transfusion and their effect on the long-term survival of patients undergoing cardiac surgery. METHODS: Between 2005 and 2012, 1170 patients with anemia who underwent elective or urgent cardiac surgery were included. A matched group of 1170 nonanemic patients was used as a control group. A binary logistic regression model was used. RESULTS: The median follow-up period was 64 months (range, 0-127). Anemic patients had higher mortality (45%, n = 526) than nonanemic patients (32%, n = 374; P < .001). Preoperative anemia was independently associated with long-term mortality (odds ratio [OR], 1.70; 95% confidence interval [CI], 1.46-2.1; P < .001), with both moderate (OR, 2.27; 95% CI, 1.72-2.99; P < .001) and mild anemia (OR, 1.39; 95% CI, 1.13-1.71; P = .002) contributing significantly. RBC transfusion was not associated with long-term mortality (OR, 1.07; 95% CI, 0.88-1.31; P = .49). There was no interaction between preoperative anemia and RBC transfusion (P = .947). CONCLUSIONS: Long-term mortality is significantly high in patients who are anemic, regardless of their transfusion status. Preoperative anemia is a strong, independent predictor of mortality and therefore should be managed before cardiac surgery.

Intravenous iron does not effectively correct preoperative anaemia in cardiac surgery: a pilot randomized controlled trial.

OBJECTIVES: Preoperative anaemia is a strong predictor of blood transfusion requirements and must be assessed for appropriate optimization before elective surgery. Iron therapy is a transfusion-sparing approach effective for increasing haemoglobin concentrations. However, its role in elective cardiac surgery and the optimal route of administration remain unknown. This single-centre, non-blinded, randomized, controlled trial compared the effectiveness of intravenous ferric carboxymaltose therapy with oral iron for anaemic patients undergoing elective cardiac surgery. METHODS: Fifty anaemic patients scheduled for elective cardiac surgery were randomized to receive either oral or intravenous iron therapy 3-8 weeks preoperatively. Changes in haemoglobin concentration were measured. Blood transfusion and postoperative outcome data were collected. RESULTS: Preoperative median increases in haemoglobin were 1.0 g/l (interquartile range -3.25 to 7.25 g/l) and 3.0 g/l (interquartile range -1.25 to 6.25 g/l) for patients receiving intravenous and oral iron, respectively (P = 0.42). The median first 12-h blood loss was significantly higher in the intravenous group (655 ml; interquartile range 162-1540 ml) compared to the oral group (313 ml; interquartile range 150-1750 ml; P < 0.007). Median increments in serum ferritin were superior for the intravenous group (median difference 313 µg/l; interquartile range 228-496) compared to the oral group (median difference 5.5 µg/l; interquartile range -1.4 to 19.4; P < 0.001). CONCLUSIONS: Increases in ferritin after intravenous iron administration were significantly greater than those after oral iron administration. There was no significant difference in haemoglobin increments between groups. Despite significantly higher intraoperative blood loss in the group receiving intravenous iron, blood transfusion requirements for both groups were not statistically different. CLINICAL TRIAL REGISTRATION: ISRCTN22158788.

Preoperative Anemia and Outcomes in Cardiovascular Surgery: Systematic Review and Meta-Analysis.

BACKGROUND: Preoperative anemia is common in patients scheduled for cardiac surgery. However, its effect on postoperative outcomes remains controversial. This meta-analysis aimed to clarify the impact of anemia on outcomes after cardiac surgery. METHODS: A literature search was conducted on MEDLINE, Embase, Cochrane, and Web of Science databases. The primary outcome was 30-day postoperative or in-hospital mortality. Secondary outcomes included acute kidney injury, stroke, blood transfusion, and infection. A meta-analytic model was used to determine the differences in the above postoperative outcomes between anemic and nonanemic patients. RESULTS: Of 1103 studies screened, 22 met the inclusion criteria. Of 114,277 patients, 23,624 (20.6%) were anemic. Anemia was associated with increased mortality (odds ratio [OR], 2.74; 95% confidence interval [CI], 2.32-3.24; I2 = 69.6%; P < .001), acute kidney injury (OR, 3.13; 95% CI, 2.37-4.12; I2 = 71.1%; P < .001), stroke (OR, 1.46; 95% CI, 1.24-1.72; I2 = 21.6%; P < .001), and infection (OR, 2.65; 95% CI, 1.98-3.55; I2 = 46.7%; P < .001). More anemic patients were transfused than nonanemic patients (33.3% vs 11.9%, respectively). No statistically significant association was found between mortality and blood transfusion (OR, 1.35; 95% CI, 0.92-1.98; I2 = 83.7%; P = .12), but we were not able to compare mortality with or without transfusion in those who were or were not anemic. CONCLUSIONS: Preoperative anemia is associated with adverse outcomes after cardiac surgery. These findings support the addition of preoperative anemia to future risk prediction models and as a target for risk modification.

Incidental abnormal CT scan findings during transcatheter aortic valve implantation assessment: incidence and implications.

Objectives: The aim of this retrospective series is to describe the prevalence and clinical significance of the incidental findings found during pre-transcatheter aortic valve implantation (TAVI) work-up and to ascertain the clinical course of such patients. Methods: Consecutive patients undergoing TAVI from 2013 to 2015 where a TAVI CT assessment was performed (n=138) were included in the study. All incidental findings that were not expected from the patient's history were discussed at the TAVI multidisciplinary meeting in order to ascertain the clinical significance of said findings and whether they would alter the proposed course of treatment. Mortality data were determined by careful retrospective case note and follow-up appointment analysis. Results: Seventy-eight patients (57%) were found to have incidental findings on pre-TAVI CT scan. The majority of patients had benign pathology with high incidence in particular of diverticular disease, pleural effusions, gallstones, hiatus hernia and degenerative spinal disease. Vascular pathology such as superior mesenteric, renal and iliac artery stenoses and abdominal aortic aneurysm was detected in seven patients. In terms of long-term mortality data, we found no significant difference between those with incidental findings and those without (p=0.48). Survival as assessed by Kaplan-Meier analysis showed no significant difference between those with and without incidental abnormal CT scan findings (p=0.98). Conclusions: Incidental findings with potential for malignancy are common in an elderly, comorbid population. Ultimately, clinical correlation and prognosis must be swiftly ascertained in order to streamline the patients down the appropriate management pathway while avoiding unnecessary delay for treatment of their aortic stenosis.

Transcatheter aortic valve implantation in decompensated aortic stenosis within the same hospital admission: early clinical experience.

Objective: Severe decompensated aortic valve stenosis is associated with noticeable reduction in survival. Until recently the options for such patients were either high-risk surgery or percutaneous balloon valvuloplasty and medical therapy which does not add any survival benefits and associated with high rate of complications. We present our experience in the use of transcatheter aortic valve implantation (TAVI) in patients with decompensated severe aortic stenosis requiring urgent intervention in the same hospital admission. Methods: In this observational study, all patients who were admitted with decompensated severe aortic stenosis were enrolled. Elective patients were excluded from the study. Perioperative records were analysed and clinical, echocardiographic and survival data were presented. Results: 76 patients with a mean age of 81±6 years were enrolled. All patients presented with New York Heart Association (NYHA) IV status. Femoral approach was performed in 86.8%. Median postoperative hospital stay was 6 days and intensive care unit admission rate was 15%. At follow-up, 61.8% of patients were in NYHA status I/II. Moderate or more paravalvular leak occurred in 5.2% of patients. Permanent pacemaker was required in 14.4% of patients. The incidence of in-hospital death was 2.6%. Kaplan-Meier analysis indicated a survival rate of 81% at 1 year. Conclusions: Urgent in-hospital TAVI is feasible as the first-line treatment in decompensated severe aortic stenosis. In our cohort, it showed to be safe and achieved satisfactory survival rates and symptom control.

Major adverse cardiac and cerebrovascular event and patients' quality of life after endoscopic vein harvesting as compared with open vein harvest (MAQEH): a pilot study.

Background: This is a prospective, comparative, pilot and follow-up (2-year postoperatively) study in patients undergoing coronary artery bypass graft surgery where the long saphenous vein was harvested either by the endoscopic vein harvest (EVH) technique or open vein harvest (OVH) technique. Quality of life (QOL) and major adverse cardiac and cerebrovascular events (MACCE) were assessed. Methods: Alive patients who were initially part of a pilot study when EVH was introduced in our institution were included (n=48 EVH, n=49 OVH). Patients were sent a QOL questionnaire (SF12v2; 12-item medical outcomes study short form health survey version 2.0), and their cardiologist and general practitioner were contacted to assess MACCE. Results: Median follow-up was 32 and 33 months, respectively. Three patients died (2 EVH, 1 OVH). Of the remaining 97 patients who were sent a questionnaire, 76% patients returned the form. More patients from the EVH group returned the QOL questionnaire (82% vs 71%). Time taken to return to normal daily activities was much shorter in EVH (median 6 (2-30) weeks) compared with OVH (median 9 (2-50) weeks) (P<0.05). QOL questionnaire revealed significant difference in physical score at follow-up: 45.3 (10.2) for EVH group and 40.7 (11.0) for OVH group (P<0.05). There was no difference in mental scores (46.9 (10.5) vs 49.2 (9.1), P=0.4). There were no significant differences in MACCEs including death between the two groups (12.2% vs 13.9%, P=0.5). Conclusion: EVH patients returned to normal daily activities faster than OVH patients and experienced better physical QOL even after 2 years postoperatively with no increase in MACCE during follow-up.

Long-term quality of life postacute kidney injury in cardiac surgery patients.

BACKGROUND: Acute renal failure after cardiac surgery is known to be associated with significant short-term morbidity and mortality. There have as yet been no major reports on long-term quality of life (QOL). This study assessed the impact of acute kidney injury (AKI) and renal replacement therapy (RRT) on long-term survival and QOL after cardiac surgery. The need for long-term RRT is also assessed. MATERIALS AND METHODS: Patients who underwent cardiac surgery between 2005 and 2011 (n = 6087) and developed AKI (RIFLE criteria, n = 570) were included. They were propensity-matched 1:1 to patients without renal impairment (control). Data were prospectively collected, and health-related QOL questionnaire was sent to patients who were alive at least 1-year postoperatively at the time of the study. RESULTS: There was no significant difference in the preoperative characteristics between the two groups (age, gender, left ventricular ejection fraction, procedure, urgency, logistic Euroscore), respectively. Median follow-up was 52 months. Survival data were available in all patients. Questionnaires were returned in 64% of eligible patients. Long-term survival was significantly lower, and QOL, in particular the physical aspect, was significantly worse for the AKI group as compared to non-AKI group (38.8 vs. 44.2, P = 0.002), especially so in patients who required RRT. In alive respondents, despite an 18% (66/359) incidence of ongoing renal follow-up, the need for late RRT was only in 1.1% (4/359). CONCLUSION: AKI and especially the need for RRT following cardiac surgery are associated with increased long-term mortality as well as worse quality of life in a propensity-matched control group.

Is the Venner-PneuX Endotracheal Tube System a Cost-Effective Option for Post Cardiac Surgery Care?

BACKGROUND: Ventilator-associated pneumonia (VAP) is common and costly. In a recent randomized controlled trial, the Venner-PneuX (VPX) endotracheal tube system (Qualitech Healthcare Limited, Maidenhead, United Kingdom) was found to be superior to standard endotracheal tubes (SET) in preventing VAP. However, VPX is considerably more expensive. We evaluated the costs and benefits of VPX to determine whether replacing SET with VPX is a cost-effective option for intensive care units. METHODS: We developed a decision analytic model to compare intubation with VPX or SET for patients requiring mechanical ventilation after cardiac operations. The model was populated with existing evidence on costs, effectiveness, and quality of life. Cost-effectiveness and cost-utility analyses were conducted from a National Health Service hospital perspective. Uncertainty was assessed through deterministic and probabilistic sensitivity analyses. RESULTS: Compared with SET, VPX is associated with an expected cost saving of £738 per patient. VPX led to a small increase in quality-adjusted life years, indicating that the device is overall less costly and more effective than SET. The probability of VPX being cost-effective at £30,000 per quality-adjusted life year is 97%. VPX would cease to be cost-effective if (1) it led to a risk reduction smaller than 0.02 compared with SET, (2) the acquisition cost of VPX was as high as £890, or (3) the cost of treating a case of VAP was lower than £1,450. CONCLUSIONS: VPX resulted in improved outcomes and savings that far offset the cost of the device, suggesting that replacing SET with VPX is overall beneficial. Findings were robust to extreme values of key variables.

Cost of treating ventilator-associated pneumonia post cardiac surgery in the National Health Service: Results from a propensity-matched cohort study.

BACKGROUND: Ventilator-associated pneumonia is associated with significant morbidity, mortality and healthcare costs. Most of the cost data that are available relate to general intensive care patients in privately remunerated institutions. This study assessed the cost of managing ventilator-associated pneumonia in a cardiac intensive care unit in the National Health Service in the United Kingdom. METHODS: Propensity-matched study of prospectively collected data from the cardiac surgical database between April 2011 and December 2014 in all patients undergoing cardiac surgery (n = 3416). Patients who were diagnosed as developing ventilator-associated pneumonia, as per the surveillance definition for ventilator-associated pneumonia (n = 338), were propensity score matched with those who did not (n = 338). Costs of treating post-op cardiac surgery patients in intensive care and cost difference if ventilator-associated pneumonia occurred based on Healthcare Resource Group categories were assessed. Secondary outcomes included differences in morbidity, mortality and cardiac intensive care unit and in-hospital length of stay. RESULTS: There were no significant differences in the pre-operative characteristics or procedures between the groups. Ventilator-associated pneumonia developed in 10% of post-cardiac surgery patients. Post-operatively, the ventilator-associated pneumonia group required longer ventilation (p < 0.01), more respiratory support, longer cardiac intensive care unit (8 vs 3, p < 0.001) and in-hospital stay (16 vs 9) days. The overall cost for post-operative recovery after cardiac surgery for ventilator-associated pneumonia patients was £15,124 compared to £6295 for non-ventilator-associated pneumonia (p < 0.01). The additional cost of treating patients with ventilator-associated pneumonia was £8829. CONCLUSION: Ventilator-associated pneumonia was associated with significant morbidity to the patients, generating significant costs. This cost was nearer to the lower end for the cost for general intensive care unit patients in privately reimbursed systems.

Is adhesive paper-tape closure of video assisted thoracoscopic port-sites safe?

Video assisted thoracoscopic surgery (VATS) is used in lung surgery for diagnostic, staging, curative and palliative purposes. The port-sites are usually sutured with dissolvable sutures. The use of adhesive paper-tape for port-site closure was assessed by a prospective randomised double-blind control trial comparing sutured to adhesive paper-tape closure. The following outcomes were assessed: incidence of clinically significant pneumothorax, wound healing using the ASEPSIS score, patient's comfort (pain score using a visual analog score), the time difference between the two techniques of wound closure and cost savings. Thirty patients were recruited in each group. No clinically significant pneumothoraces occurred in either group. There were no significant differences between the two groups in terms of immediate post-operative pain scores, wound cosmesis and wound complications. It was quicker to close the wound with adhesive paper-tape with a mean time of closure per unit length of wound of 9.3 and 2.2s/mm for the groups, respectively. The cost for wound closure (per patient) was $0.8 for the adhesive paper-tape group and $4.00 for the sutures.

The use of the RenalGuard system in cardiac surgery with cardiopulmonary bypass: a first in man prospective, observational, feasibility pilot study.

OBJECTIVES: As proof of concept, this prospective, observational study assessed the feasibility and early clinical outcomes of performing on-pump cardiac surgery with the RenalGuard system. BACKGROUND: Acute kidney injury (AKI) is reported in up to 30% of patients undergoing cardiac surgery and is a recognised independent predictor of both morbidity and mortality. Forced diuresis with the RenalGuard system reduces the incidence of AKI during percutaneous coronary intervention procedures but its use in cardiac surgery has not been explored. METHODS: Ten consecutive patients who were at risk of developing AKI during cardiac surgery were selected. The RenalGuard system was used to facilitate forced diuresis using weight-adjusted intravenous furosemide while maintaining neutral fluid balance by matched intravenous fluid replacement. This regimen was initiated preoperatively in all patients and continued for 6-12 hours postoperatively. Serum creatinine, electrolytes and need for renal replacement were documented in all patients. RESULTS: The RenalGuard system functioned successfully in all patients and facilitated high perioperative urine outputs, even when patients were placed on cardiopulmonary bypass (CPB). There were no incidences of significant (A) electrolyte imbalance, (B) changes in haemoglobin levels or (C) pulmonary oedema. No patients developed AKI within 36 hours of surgery despite one patient developing cardiac tamponade 8 hours postoperatively and one patient developing paralytic ileus. One patient, however, was 'electively' haemofiltered on day 2 after developing acute right ventricular failure. The median intensive care stay was 1.5 (1, 5) days. CONCLUSION: The RenalGuard system can be used successfully in patients undergoing cardiac surgery with CPB and may reduce the incidence of AKI in at-risk patients. TRIAL REGISTRATION: NCT02974946; Pre-results.

Cerebral oxygenation monitoring in patients with bilateral carotid stenosis undergoing urgent cardiac surgery: Observational case series.

BACKGROUND: Patients with significant bilateral carotid artery stenosis requiring urgent cardiac surgery have an increased risk of stroke and death. The optimal management strategy remains inconclusive, and the available evidence does not support the superiority of one strategy over another. MATERIALS AND METHODS: A number of noninvasive strategies have been developed for minimizing perioperative stroke including continuous real-time monitoring of cerebral oxygenation with near-infrared spectroscopy (NIRS). The number of patients presenting with this combination (bilateral significant carotid stenosis requiring urgent cardiac surgery) in any single institution will be small and hence there is a lack of large randomized studies. RESULTS: This case series describes our early experience with NIRS in a select group of patients with significant bilateral carotid stenosis undergoing urgent cardiac surgery (n = 8). In contrast to other studies, this series is a single surgeon, single center study, where the entire surgery (both distal ends and proximal ends) was performed during single aortic clamp technique, which effectively removes several confounding variables. NIRS monitoring led to the early recognition of decreased cerebral oxygenation, and corrective steps (increased cardiopulmonary bypass flow, increased pCO 2 , etc.,) were taken. CONCLUSION: The study shows good clinical outcome with the use of NIRS. This is our "work in progress," and we aim to conduct a larger study.

The role of side stream dark field microvasculature imaging in a rare case of vancomycin-resistant enterococcal endocarditis complicated by heparin-induced thrombocytopenia.

Sidestream dark field (SDF) imaging allows direct visualization of microvascular architecture and function. We examine the role of an SDF imaging device in visualizing the sub-lingual microvasculature as a surrogate for splanchnic microperfusion. We demonstrate good correlation between current monitoring techniques and the SDF imaging device in a rare case of vancomycin-resistant enterococcal (VRE) sepsis along with heparin-induced thrombocytopenia (HIT). To the best of our knowledge, VRE endocarditis with concurrent HIT has not been described in literature. The role of SDF imaging may predict the earlier need for escalation of care, improving morbidity and mortality.