Perioperative renal protection. Best Pract Res Clin Anaesthesiol. 2008;22:193-208. [PMID: 18494397 DOI: 10.1016/j.bpa.2007.08.005]

Effect of meloxicam or robenacoxib administration timing on renal function and postoperative analgesia in cats undergoing ovariohysterectomy: A randomized, blinded, controlled clinical trial

We evaluated the effect of administration timing of meloxicam and robenacoxib on renal function, platelet cyclo-oxygenase and perioperative analgesia in 60 cats undergoing ovariohysterectomy, in a prospective randomized blinded controlled study. Twelve cats were randomly allocated to one subcutaneous treatment group: meloxicam (0.2 mg/kg) or robenacoxib (2 mg/kg) at admission (MA, RA), at induction (MI, RI) and robenacoxib at the end of surgery (RE). All cats received the same anaesthesia protocol. Plasma renin activity (PRA), plasma creatinine, drug concentrations and serum thromboxane (TxB2) were measured sequentially. Anaesthesia significantly increased PRA, as activity at end of the surgery was higher than 2 h later (mean ± SD: 26.6 ± 2.8 versus 10.0 ± 3.9 ng/mL/h). PRA remained higher at 2 h post-surgery in admission groups compared to induction groups (p = .01). Serum TxB2 was lower with meloxicam than robenacoxib (p = .001), and was lower in the MA than each robenacoxib group at catheter placement. Admission groups (16/24 from RA and MA groups) received earlier rescue analgesia than other groups (p = .033). In conclusion, the renin-angiotensin system was activated during anaesthesia despite cyclo-oxygenase inhibition, possibly due to hypotension or surgical stimulation. There was no effect of drug or timing on the markers of renal function but one cat receiving meloxicam at induction had suspected IRIS grade II acute kidney injury.

The Role of the Superior Cervical Sympathetic Ganglion in Ischemia Reperfusion-Induced Acute Kidney Injury in Rats

Acute kidney injury (AKI) has been found to be a serious clinical problem with high morbidity and mortality, and is associated with acute inflammatory response and sympathetic activation that subsequently play an important role in the development of AKI. It is well known that the sympathetic nervous system (SNS) and immune system intensely interact and mutually control each other in order to maintain homeostasis in response to stress or injury. Evidence has shown that the superior cervical sympathetic ganglion (SCG) participates in the bidirectional network between the immune and the SNS, and that the superior cervical ganglionectomy has protective effect on myocardial infarction, however, the role of the SCG in the setting of renal ischemic reperfusion injury has not been studied. Here, we sought to determine whether or not the SCG modulates renal ischemic reperfusion (IR) injury in rats. Our results showed that bilateral superior cervical ganglionectomy (SCGx) 14 days before IR injury markedly reduced the norepinephrine (NE) in plasma, and down-regulated the increased expression of tyrosine hydroxylase (TH) in the kidney and hypothalamus. Sympathetic denervation by SCGx in the AKI group increased the level of blood urea nitrogen (BUN) and kidney injury molecule-1 (KIM-1), and exacerbated renal pathological damage. Sympathetic denervation by SCGx in the AKI group enhanced the expression of pro-inflammatory cytokines in plasma, kidney and hypothalamus, and increased levels of Bax in denervated rats with IR injury. In addition, the levels of purinergic receptors, P2X3R and P2X7R, in the spinal cord were up-regulated in the denervated rats of the IR group. In conclusion, these results demonstrate that the sympathetic denervation by SCGx aggravated IR-induced AKI in rats via enhancing the inflammatory response, thus, the activated purinergic signaling in the spinal cord might be the potential mechanism in the aggravated renal injury.

Effect of zinc oxide nanoparticles and ferulic acid on renal ischemia/reperfusion injury: possible underlying mechanisms

OBJECTIVES

The present study examined the effects of ferulic acid (FA) and Zinc oxide nanoparticles (ZnO-NPs) and a combination of both on renal ischemia/reperfusion injury (IRI) in rats and their possible underlying mechanisms.

METHODS

two-hundreds male Sprague Dawley rats were randomly allocated into the 5 groups; i) sham group, ii) control (IRI) group (occlusion of the left renal pedicle for 45 min), iii) FA group as IRI group with FA (100 mg/Kg oral 24 hrs before ischemia), iv) ZnO-NPs group as IRI group with ZnO-NPs single 5 mg/Kg i.p. 2 hrs before ischemia and v) FA + ZnO-NPs group as IRI group with both FA and ZnO-NPs in the same previous doses. According to the reperfusion times, each group was further subdivided into 4 hr, 24 hr, 48 hr and 7 days reperfusion subgroups.

RESULTS

administration of either FA or ZnO-NPs caused significant improvement in the elevated serum creatinine and BUN and malondialdehyde (MDA) concentrations and expression of TNF-α, Bax, caspase-3 in kidney tissues with significant rise in the creatinine clearance, the activities of catalase (CAT) and superoxide dismutase (SOD) and the expression of HO-1, HIF-1α genes and proliferation marker (ki67) in kidney tissues compared to IRI group (p < 0.05). Moreover, a combination of both agents produced more significant improvement in the studied parameters than each agent did alone (p < 0.05).

CONCLUSIONS

Both FA and ZnO-NPs exerted cytoprotective effects against ischemic kidney injury and a combination of both exhibited more powerful renoprotective effect. This renoprotective effect might be due to suppression of oxidative stress, enhancement of cell proliferation (ki67), upregulation of antioxidant genes (Nrf2, HO-1 and HIF-1α) and downregulation of inflammatory cytokine (TNF-α) and apoptotic genes (caspase-3 and Bax).

Incidence and Predictors of Acute Kidney Injury in Patients Undergoing Elective Hepatic Resection for Malignant Tumors: A 3-year Prospective Observational Study

Background

Acute kidney injury (AKI) is common in patients undergoing major surgeries, and leads to the need for renal replacement therapy and increased morbidity, intensive care unit (ICU) and hospital length of stay (LOS), cost, and mortality. We evaluated the incidence and predictors of postoperative AKI in patients undergoing hepatic resections and their short-term outcomes.

Materials and methods

This prospective observational study was conducted over a 3-year period in 180 patients undergoing elective hepatic resections for a variety of indications. We used the Acute Kidney Injury Network criteria to determine the incidence of AKI at 72 hours. Perioperative variables contributing to the development of AKI and the short-term postoperative outcomes of patients were evaluated.

Results

Postoperative AKI occurred in 29.4% of patients. Persistent renal dysfunction was seen in five patients. Development of AKI was associated with hepatic failure (18.5 vs 5.5%, p < 0.005), prolonged ICU (2 vs 1 days, p < 0.001) and hospital LOS (11 vs 8 days, p < 0.004), and increased ICU and hospital mortality (9.6 vs 1.4%, p < 0.02). Age [OR (odds ratio) 1.033, 95% CI (confidence interval) 1.003–1.065, p = 0.03], BMI (body mass index) (OR 1.131, 95% CI 1.043–1.227, p = 0.003), and need for postoperative ventilation (OR 3.456, 95% CI 1.593–7.495, p = 0.002) were independent predictors of AKI.

Conclusion

AKI after elective hepatic resection occurred in nearly one-third of our patients. Persistent renal dysfunction was seen in five patients. Age, BMI, and need for postoperative ventilation were independent predictors of postoperative AKI. (CTRI reg. No.: CTRI/2016/06/007044).

How to cite this article

Joshi M, Milmile R, Dhakane P, Bhosale SJ, Kulkarni AP. Incidence and Predictors of Acute Kidney Injury in Patients Undergoing Elective Hepatic Resection for Malignant Tumors: A 3-year Prospective Observational Study. Indian J Crit Care Med 2021;25(4):398–404.

Anesthetic Management and 30-Day Outcomes After Renal Autotransplantation

Background: Renal autotransplantation is a complex procedure performed for various indications such as treatment of renal vascular and urologic lesions and loin pain hematuria syndrome (LPHS). Because of the rarity of the procedure, few reports have been published, and little is known about anesthetic management and postoperative outcomes of patients with LPHS. The goal of this study was to review and describe all cases of renal autotransplantation performed at Cleveland Clinic during a specified period, focusing on anesthetic management and postoperative 30-day outcomes.

Methods: We performed a retrospective review of the records of all patients who underwent renal autotransplantation from 2005 to 2014 at the Cleveland Clinic and collected demographic, anesthetic, surgical, and postoperative data.

Results: A total of 64 patients underwent renal autotransplantation from 2005 to 2014. The most frequent indications were nephrolithiasis and LPHS. General endotracheal anesthesia with epidural for pain control was used in 47% of cases. Median duration of anesthesia was 528 minutes. Most patients were sent to a regular nursing floor postoperatively, but 28% of patients required intensive care unit admission. Two patients developed graft ischemia, and 1 patient developed graft failure requiring nephrectomy. No anesthetic-related complications and no mortality were associated with this procedure during the study.

Conclusion: Renal autotransplantation is a safe option for patients with LPHS. Additional studies are needed to assess the effect of intraoperative anesthetic management on outcomes in this patient population.

Renal proximal tubular NEMO plays a critical role in ischemic acute kidney injury

We determined that renal proximal tubular (PT) NF-κB essential modulator (NEMO) plays a direct and critical role in ischemic acute kidney injury (AKI) using mice lacking renal PT NEMO and by targeted renal PT NEMO inhibition with mesoscale nanoparticle-encapsulated NEMO binding peptide (NBP MNP). We subjected renal PT NEMO-deficient mice, WT mice, and C57BL/6 mice to sham surgery or 30 minutes of renal ischemia and reperfusion (IR). C57BL/6 mice received NBP MNP or empty MNP before renal IR injury. Mice treated with NBP MNP and mice deficient in renal PT NEMO were protected against ischemic AKI, having decreased renal tubular necrosis, inflammation, and apoptosis compared with control MNP-treated or WT mice, respectively. Recombinant peptidylarginine deiminase type 4 (rPAD4) targeted kidney PT NEMO to exacerbate ischemic AKI in that exogenous rPAD4 exacerbated renal IR injury in WT mice but not in renal PT NEMO-deficient mice. Furthermore, rPAD4 upregulated proinflammatory cytokine mRNA and NF-κB activation in freshly isolated renal proximal tubules from WT mice but not from PT NEMO-deficient mice. Taken together, our studies suggest that renal PT NEMO plays a critical role in ischemic AKI by promoting renal tubular inflammation, apoptosis, and necrosis.

Intraoperative Fluid Balance and Perioperative Outcomes After Aortic Valve Surgery

BACKGROUND

The effect of intraoperative fluid balance on postoperative acute kidney injury (AKI) in cardiac surgical patients is poorly defined.

METHODS

In this retrospective study of patients undergoing aortic valve replacement for aortic stenosis, the primary outcome of interest was postoperative AKI. Secondary outcomes were postoperative fluid balance, cardiac index, vasopressor use, hospital-free days, stroke, myocardial infarction, hospital readmission, and 30- and 90-day mortality.

RESULTS

A total of 2327 patients were analyzed. Positive intraoperative fluid balance was associated with lower odds of AKI; the lowest odds were in the 20- to 39-mL/kg group (odds ratio, 0.56; 95% confidence interval, 0.38-0.81; P = .002). Positive intraoperative fluid balance was associated with a lower postoperative fluid balance. Increased ultrafiltration volume was associated with increased postoperative fluid resuscitation and vasopressor use. AKI was associated with increased 30- and 90-day mortality. Increased fluid balance was associated with increased odds of myocardial infarction and 30-day mortality. Increased ultrafiltration volume was associated with increased odds of 30- and 90-day mortality.

CONCLUSIONS

In patients who underwent aortic valve replacement for aortic stenosis, positive intraoperative fluid balance was associated with decreased odds of AKI. Patients developing AKI had increased 30- and 90-day mortality. Although the overall incidence was low, increased intraoperative fluid balance was associated with myocardial infarction and 30-day mortality, whereas increased ultrafiltration volume was associated with 30- and 90-day morality. Prospective studies are needed to better define proper intraoperative fluid management in patients undergoing cardiac surgery.

Selective nanoparticle-mediated targeting of renal tubular Toll-like receptor 9 attenuates ischemic acute kidney injury

We developed an innovative therapy for ischemic acute kidney injury with discerning kidney-targeted delivery of a selective Toll-like receptor 9 (TLR9) antagonist in mice subjected to renal ischemia reperfusion injury. Our previous studies showed that mice deficient in renal proximal tubular TLR9 were protected against renal ischemia reperfusion injury demonstrating a critical role for renal proximal tubular TLR9 in generating ischemic acute kidney injury. Herein, we used 300-400 nm polymer-based mesoscale nanoparticles that localize to the renal tubules after intravenous injection. Mice were subjected to sham surgery or 30 minutes renal ischemia and reperfusion injury after receiving mesoscale nanoparticles encapsulated with a selective TLR9 antagonist (unmethylated CpG oligonucleotide ODN2088) or mesoscale nanoparticles encapsulating a negative control oligonucleotide. Mice treated with the encapsulated TLR9 antagonist either six hours before renal ischemia, at the time of reperfusion or 1.5 hours after reperfusion were protected against ischemic acute kidney injury. The ODN2088-encapsulated nanoparticles attenuated renal tubular necrosis, inflammation, decreased proinflammatory cytokine synthesis. neutrophil and macrophage infiltration and apoptosis, decreased DNA fragmentation and caspase 3/8 activation when compared to the negative control nanoparticle treated mice. Taken together, our studies further suggest that renal proximal tubular TLR9 activation exacerbates ischemic acute kidney injury by promoting renal tubular inflammation, apoptosis and necrosis after ischemia reperfusion. Thus, our studies suggest a potential promising therapy for ischemic acute kidney injury with selective kidney tubular targeting of TLR9 using mesoscale nanoparticle-based drug delivery.

6-Shogaol protects against ischemic acute kidney injury by modulating NF-κB and heme oxygenase-1 pathways

Acute kidney injury (AKI) due to renal ischemia-reperfusion (I/R) is a major clinical problem without effective therapy. Ginger is one of the most widely consumed spices in the world, and 6-shogaol, a major ginger metabolite, has anti-inflammatory effects in neuronal and epithelial cells. Here, we demonstrate our novel findings that 6-shogaol treatment protected against renal I/R injury with decreased plasma creatinine, blood urea nitrogen, and kidney neutrophil gelatinase-associated lipocalin mRNA synthesis compared with vehicle-treated mice subjected to renal I/R. Additionally, 6-shogaol treatment reduced kidney inflammation (decreased proinflammatory cytokine and chemokine synthesis as well as neutrophil infiltration) and apoptosis (decreased TUNEL-positive renal tubular cells) compared with vehicle-treated mice subjected to renal I/R. In cultured human and mouse kidney proximal tubule cells, 6-shogaol significantly attenuated TNF-α-induced inflammatory cytokine and chemokine mRNA synthesis. Mechanistically, 6-shogaol significantly attenuated TNF-α-induced NF-κB activation in human renal proximal tubule cells by reducing IKKαβ/IκBα phosphorylation. Furthermore, 6-shogaol induced a cytoprotective chaperone heme oxygenase (HO)-1 via p38 MAPK activation in vitro and in vivo. Consistent with these findings, pretreatment with the HO-1 inhibitor zinc protoporphyrin IX completely prevented 6-shogaol-mediated protection against ischemic AKI in mice. Taken together, our study showed that 6-shogaol protects against ischemic AKI by attenuating NF-κB activation and inducing HO-1 expression. 6-Shogaol may provide a potential therapy for ischemic AKI during the perioperative period.

The impact of immunosuppression on postoperative graft function after graft-unrelated surgery: a retrospective controlled cohort study

Background

Physicians are faced with a growing number of patients after renal transplantation undergoing graft-unrelated surgery. So far, little is known about the postoperative restitution of graft function and the risk factors for a poor outcome.

Methods

One hundred one kidney transplant recipients undergoing graft-unrelated surgery between 2005 and 2015 were reviewed retrospectively. A risk analysis was performed and differences in creatinine, GFR and immunosuppressive treatment were evaluated. Additional, a comparison with a case-matched non-transplanted control group were performed.

Results

Preoperative creatinine averaged 1.88 mg / dl [0.62–5.22 mg / dl] and increased to 2.49 mg / dl [0.69–8.30 mg / dl] postoperatively. Acute kidney failure occurred in 18 patients and 14 patients had a permanent renal failure. Significant risk factors for the development of postoperative renal dysfunction were female gender, a preoperative creatinine above 2.0 mg / dl as well as a GFR below 40 ml / min and emergency surgery. Patients with tacrolimus and mycophenolate mofetil treatment showed a significant lower risk of renal dysfunction than patients with other immunosuppressants postoperatively. Contrary to that, the risk of patients with cyclosporine treatment was significantly increased. Transplanted patients showed a significantly increased rate of postoperative renal dysfunction.

Conclusions

The choice of immunosuppressant might have an impact on graft function and survival of kidney transplant recipients after graft-unrelated surgery. Further investigations are needed.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1358-2) contains supplementary material, which is available to authorized users.

Ferulic Acid Protected from Kidney Ischemia Reperfusion Injury in Mice: Possible Mechanism Through Increasing Adenosine Generation via HIF-1α

Ferulic acid (FA), derived from fruits and vegetables, is well-known as a potent antioxidant of scavenging free radicals. However, the role and underlying mechanism of FA on kidney ischemia reperfusion (I/R) injury are limited. Here, we explored the effects of FA on kidney I/R injury. The kidney I/R injury models were carried out by clamping bilateral pedicles for 35 min followed by reperfusion for 24 h. Mice were orally pretreated with different doses of FA for three times 24 h before I/R. The renal function was assessed by serum creatine (Scr) and blood urea nitrogen (BUN). Kidney histology was examined by hematoxylin and eosin (HE) staining and terminal deoxynucleotidly transferased UTP nick-end labeling (TUNEL) assay. Proinflammatory cytokines, caspase-3 activity, adenosine generation, adenosine signaling molecules, and hypoxia inducible factor-1 alpha (HIF-1α) were also detected, respectively. The siHIF-1α adenovirus vectors were in vivo used to inhibit the expression of HIF-1α. The results showed that FA significantly attenuated kidney damage in renal I/R-operated mice as indicated by reducing levels of Scr and BUN, ameliorating renal pathological structural changes, and tubular cells apoptosis. Moreover, FA pretreatment inhibited I/R-induced renal proinflammatory cytokines and neutrophils recruitment. Interestingly, the levels of HIF-α, CD39, and CD73 mRNA and protein as well as adenosine production were all significantly increased after FA pretreatment in the kidney of I/R-performed mice, and inhibiting HIF-α expression using siRNA abolished this protection of FA on I/R-induced acute kidney injury as evidenced by more severe renal damage and reduced adenosine production. Our findings indicated that FA protected against kidney I/R injury by reducing apoptosis, alleviating inflammation, increasing adenosine generation, and upregulating CD39 and CD73 expression, which might be mediated by HIF-1α.

Kidney Proximal Tubular TLR9 Exacerbates Ischemic Acute Kidney Injury

The role for kidney TLR9 in ischemic acute kidney injury (AKI) remains unclear. In this study, we tested the hypothesis that renal proximal tubular TLR9 activation exacerbates ischemic AKI by promoting renal tubular epithelial apoptosis and inflammation. To test this hypothesis, we generated mice lacking TLR9 in renal proximal tubules (TLR9^fl/fl PEPCK Cre mice). Contrasting previous studies in global TLR9 knockout mice, mice lacking renal proximal tubular TLR9 were protected against renal ischemia/reperfusion (IR) injury, with reduced renal tubular necrosis, inflammation (decreased proinflammatory cytokine synthesis and neutrophil infiltration), and apoptosis (decreased DNA fragmentation and caspase activation) when compared with wild-type (TLR9^fl/fl) mice. Consistent with this, a selective TLR9 agonist oligonucleotide 1668 exacerbated renal IR injury in TLR9^fl/fl mice but not in renal proximal tubular TLR9-null mice. Furthermore, in cultured human and mouse proximal tubule cells, TLR9-selective ligands induced NF-κB activation, proinflammatory cytokine mRNA synthesis, as well as caspase activation. We further confirm in the present study that global TLR9 deficiency had no impact on murine ischemic AKI. Taken together, our studies show that renal proximal tubular TLR9 activation exacerbates ischemic AKI by promoting renal tubular inflammation, apoptosis as well as necrosis, after IR via NF-κB and caspase activation. Our studies further suggest the complex nature of TLR9 activation, as renal tubular epithelial TLR9 promotes cell injury and death whereas TLR9 signaling in other cell types may promote cytoprotective effects.

Divergent roles for kidney proximal tubule and granulocyte PAD4 in ischemic AKI

We previously demonstrated that kidney peptidylarginine deiminase-4 (PAD4) plays a critical role in ischemic acute kidney injury (AKI) in mice by promoting renal tubular inflammation and neutrophil infiltration (Ham A, Rabadi M, Kim M, Brown KM, Ma Z, D'Agati V, Lee HT. Am J Physiol Renal Physiol 307: F1052-F1062, 2014). Although the role of PAD4 in granulocytes including neutrophils is well known, we surprisingly observed profound renal proximal tubular PAD4 induction after renal ischemia-reperfusion (I/R) injury. Here we tested the hypothesis that renal proximal tubular PAD4 rather than myeloid-cell lineage PAD4 plays a critical role in exacerbating ischemic AKI by utilizing mice lacking PAD4 in renal proximal tubules (PAD4ff PEPCK Cre mice) or in granulocytes (PAD4ff LysM Cre mice). Mice lacking renal proximal tubular PAD4 were significantly protected against ischemic AKI compared with wild-type (PAD4ff) mice. Surprisingly, mice lacking PAD4 in myeloid cells were also protected against renal I/R injury although this protection was less compared with renal proximal tubular PAD4-deficient mice. Renal proximal tubular PAD4-deficient mice had profoundly reduced renal tubular apoptosis, whereas myeloid-cell PAD4-deficient mice showed markedly reduced renal neutrophil infiltration. Taken together, our studies suggest that both renal proximal tubular PAD4 as well as myeloid-cell lineage PAD4 play a critical role in exacerbating ischemic AKI. Renal proximal tubular PAD4 appears to contribute to ischemic AKI by promoting renal tubular apoptosis, whereas myeloid-cell PAD4 is preferentially involved in promoting neutrophil infiltration to the kidney and inflammation after renal I/R.

Preoperative hydration with 0.9% normal saline to prevent acute kidney injury after major elective open abdominal surgery: A randomised controlled trial

BACKGROUND

Postoperative acute kidney injury (AKI) is the second leading cause of hospital-acquired AKI. Although many preventive strategies have been tested, none of them has been totally effective.

OBJECTIVE

We investigated whether preoperative intravenous hydration with 0.9% normal saline could prevent postoperative AKI.

DESIGN

Randomised controlled trial.

SETTING

University Ramón y Cajal Hospital, Spain, from June 2006 to February 2011.

PATIENTS

Total 328 inpatients scheduled for major elective open abdominal surgery.

INTERVENTION

0.9% normal saline at a dose of 1.5 ml kg h for 12 h before surgery.

MAIN OUTCOME MEASURES

The primary outcome was the overall postoperative AKI incidence during the first week after surgery defined by risk, injury, failure, loss, end-stage kidney disease (RIFLE) and AKI network (AKIN) creatinine criteria. Secondary endpoints were the need for ICU admission, renal replacement therapy during the study period and adverse events and hospital mortality during hospital admission.

RESULTS

There was no difference in the incidence of AKI between groups: 4.7% in the normal saline group versus 5.0% in the control group and 11.4% in the 0.9% normal saline group versus 7.9% in the control group as assessed by the RIFLE and AKIN creatinine criteria, respectively. Absolute risk reductions (95% confidence interval) were -0.3% (-5.3 to 4.7%) for RIFLE and 3.5% (-10.2 to 3.6%) for AKIN. ICU admission after surgery was required in 44.5% of all participants. Only 2 (0.7%) patients required renal replacement therapy during the first week after surgery. The analysis of adverse events did not show statistically significant differences between the groups except for pain. In our population, 8 (2.4%) patients died during their hospital admission.

CONCLUSION

Intravenous hydration with 0.9% normal saline before major open abdominal surgery was not effective in preventing postoperative AKI. No safety concerns were identified during the trial.

TRIAL REGISTRATIONS

Clinical trials.gov: NCT00953940 and EUDRA CT: 2005-004755-35.

Risk factors for postoperative renal dysfunction following open surgical repair of abdominal aortic aneurysms retrospective analysis

Objectives

To identify the risk factors for postoperative renal dysfunction after open surgical repair (OSR) of abdominal aortic aneurysms (AAAs) and to establish a scoring system.

Results

The overall 30-day mortality rates were 22.0%(ruptured) vs 2.6% (unruptured), respectively. For the ruptured group, the independent risk factors were hemodynamic instability (P = 0.002) blood loss >1 L (P = 0.041) and preoperative creatinine >150 μmol/L (P < 0.001). By contrast, for the unruptured group, factors were smoking (P = 0.028), blood loss >1 L (P = 0.018), and antihypertensive drugs (P < 0.001). The areas under the curve of the WCRDA scoring system are 0.794 (95% confidence interval (CI) 0.686–0.902, P < 0.001) and 0.811 (95% CI 0.691–0.932, P < 0.001) for the ruptured and unruptured groups, respectively.

Conclusions

Hemodynamic instability, blood loss >1 L and Hb <90 g/L are independent risk factors for postoperative renal dysfunction following rAAA OSR, whereas smoking, blood loss >1 L, and antihypertensive drugs are independent risk factors. WCRDA performs well in predicting postoperative renal dysfunction.

Materials and Methods

287 patients from the Vascular Department of West China Hospital, Sichuan University, who were planned to perform OSR for AAA from November 2003 to January 2017. 274 patients underwent OSR for AAA were finally included in the study. A total of 118 patients had ruptured AAA and 156 unruptured AAA.

The patients were divided into the ruptured and unruptured groups. Logistic regression was used to identify the independent risk factors for postoperative renal dysfunction. The receiver operating characteristic curve was used to evaluate the scoring system.

ATP induces PAD4 in renal proximal tubule cells via P2X7 receptor activation to exacerbate ischemic AKI

We previously demonstrated that renal tubular peptidylarginine deiminase-4 (PAD4) is induced after ischemia-reperfusion (IR) injury and this induction of PAD4 exacerbates ischemic acute kidney injury (AKI) by promoting renal tubular inflammation and neutrophil infiltration. However, the mechanisms of renal tubular PAD4 induction after IR remain unknown. Here, we tested the hypothesis that ATP, a proinflammatory danger-associated molecular pattern (DAMP) ligand released from necrotic cells after IR injury, induces renal tubular PAD4 and exacerbates ischemic AKI via P2 purinergic receptor activation. ATP as well as ATPγS (a nonmetabolizable ATP analog) induced PAD4 mRNA, protein, and activity in human and mouse renal proximal tubule cells. Supporting the hypothesis that ATP induces renal tubular PAD4 via P2X7 receptor activation, A804598 (a selective P2X7 receptor antagonist) blocked the ATP-mediated induction of renal tubular PAD4 whereas BzATP (a selective P2X7 receptor agonist) mimicked the effects of ATP by inducing renal tubular PAD4 expression and activity. Moreover, ATP-mediated calcium influx in renal proximal tubule cells was blocked by A804598 and was mimicked by BzATP. P2X7 activation by BzATP also induced PAD4 expression and activity in mouse kidney in vivo. Finally, supporting a critical role for PAD4 in P2X7-mediated exacerbation of renal injury, BzATP exacerbated ischemic AKI in PAD4 wild-type mice but not in PAD4-deficient mice. Taken together, our studies show that ATP induces renal tubular PAD4 via P2X7 receptor activation to exacerbate renal tubular inflammation and injury after IR.

Administration of Tetrahydrobiopterin (BH4) Protects the Renal Microcirculation From Ischemia and Reperfusion Injury

BACKGROUND

Abdominal aortic aneurysm surgery with suprarenal cross-clamping is often associated with renal injury. Although the mechanism underlying such injury is unclear, tissue ischemia and reperfusion, which induces endothelial dysfunction and decreases the availability of tetrahydrobiopterin (BH4), may play a role. We evaluated whether BH4 administration prevents renal ischemia/reperfusion injury in an animal model of aortic cross-clamping.

METHODS

Nineteen anesthetized, mechanically ventilated, and invasively monitored adult sheep were randomized into 3 groups: sham animals (n = 5) that underwent surgical preparation but no aortic clamping; an ischemia/reperfusion group (n = 7), where the aorta was clamped above the renal arteries for 1 hour, and a BH4 group (n = 7), in which animals received 20 mg/kg of BH4 followed by aortic cross-clamp for 1 hour. Animals were followed for a maximum of 6 hours after reperfusion. The renal microcirculation was evaluated at baseline (before clamping), and 1, 4, and 6 hours after reperfusion using side-stream dark field videomicroscopy. The renal lactate-to-pyruvate ratio was evaluated using microdialysis. The primary outcome was the change in proportion of small perfused vessels before and after injury. Secondary outcomes were renal tissue redox state and renal function.

RESULTS

Ischemia/reperfusion injury was associated with increases in heart rate and mean arterial pressure, which were blunted by BH4 administration. From the first to the sixth hour after reperfusion, the small vessel density (estimated mean difference [EMD], 1.03; 95% confidence interval [CI], 0.41-1.64; P = .003), perfused small vessel density (EMD, 0.84; 95% CI, 0.29-1.39; P = .005), and proportion of perfused small vessels (EMD, 8.60; 95% CI, 0.85-16.30; P = .031) were altered less in the BH4 than in the ischemia/reperfusion group. The renal lactate-to-pyruvate ratios were lower in the cortex in the BH4 than in the ischemia/reperfusion group from the first to the sixth hour after reperfusion (EMD, -19.16; 95% CI, -11.06 to 33.16; P = .002) and in the medulla from the first to the fourth hour (EMD, -26.62; 95% CI, -18.32 to 38.30; P = .020; and EMD, -8.68; 95% CI, -5.96 to 12.65; P = .019). At the sixth hour, serum creatinine was lower in the BH4 than in the ischemia/reperfusion group (EMD, -3.36; 95% CI, -0.29 to 1.39; P = .026).

CONCLUSIONS

In this sheep model of renal ischemia/reperfusion, BH4 pretreatment reduced renal microvascular injury and improved renal metabolism and function. Further work is needed to clarify the potential role of BH4 in ischemia/reperfusion injury.

Effects of chronic alcohol exposure on ischemia-reperfusion-induced acute kidney injury in mice: the role of β-arrestin 2 and glycogen synthase kinase 3

Little is known about the effects of chronic alcohol intake on the outcome of acute kidney injury (AKI). Hence, we examined the effects of chronic alcohol intake on the development of renal fibrosis following AKI in an animal model of bilateral renal ischemia–reperfusion (IR) injury. We first found that chronic alcohol exposure exacerbated bilateral IR-induced renal fibrosis and renal function impairment. This phenomenon was associated with increased bilateral IR-induced extracellular matrix deposition and an increased myofibroblast population as well as increased bilateral IR-induced expression of fibrosis-related genes in the kidneys. To explore the mechanisms underlying this phenomenon, we showed that chronic alcohol exposure enhanced β-arrestin 2 (Arrb2) expression and Akt and glycogen synthase kinase-3 (GSK3)β activation in the kidneys. Importantly, pharmacological GSK3 inhibition alleviated bilateral IR-induced renal fibrosis and renal function impairment. Furthermore, we demonstrated that Arrb2^−/− mice exhibited resistance to IR-induced renal fibrosis and renal function impairment following chronic alcohol exposure, and these effects were associated with attenuated GSK3β activation in the kidneys. Taken together, our results suggest that chronic alcohol exposure may potentiate AKI via β-arrestin 2/Akt/GSK3β-mediated signaling in the kidney.

Effects of acute kidney injury after liver resection on long-term outcomes

Background

To investigate the effects of acute kidney injury (AKI) after liver resection on the long-term outcome, including mortality and renal dysfunction after hospital discharge.

Methods

We conducted a historical cohort study of patients who underwent liver resection for hepatocellular carcinoma with sevoflurane anesthesia between January 2004 and October 2011, survived the hospital stay, and were followed for at least 3 years or died within 3 years after hospital discharge. AKI was diagnosed based on the Acute Kidney Injury Network classification within 72 hours postoperatively. In addition to the data obtained during hospitalization, serum creatinine concentration data were collected and the glomerular filtration rate (GFR) was estimated after hospital discharge.

Results

AKI patients (63%, P = 0.002) were more likely to reach the threshold of an estimated GFR (eGFR) of 45 ml/min/1.73 m² within 3 years than non-AKI patients (31%) although there was no significant difference in mortality (33% vs. 29%). Cox proportional hazard regression analysis showed that postoperative AKI was significantly associated with the composite outcome of mortality or an eGFR of 45 ml/min/1.73 m² (95% CI of hazard ratio, 1.05–2.96, P = 0.033), but not with mortality (P = 0.699), the composite outcome of mortality or an eGFR of 60 ml/min/1.73 m² (P =0.347).

Conclusions

After liver resection, AKI patients may be at higher risk of mortality or moderate renal dysfunction within 3 years. These findings suggest that even after discharge from the hospital, patients who suffered AKI after liver resection may need to be followed-up regarding renal function in the long term.

Anesthesia for the Patient with Concomitant Hepatic and Renal Impairment

Hepatic and renal disease are common comorbidities in patients presenting for intermediate- and high-risk surgery. With the evolution of perioperative medicine, anesthesiologists are encountering more patients who have significant hepatic and renal disease, both acute and chronic in nature. It is important that anesthesiologists have an in-depth understanding of the physiologic derangements seen with hepatic and renal disease to evaluate and manage these patients appropriately. Perioperative management requires an understanding of the physiologic perturbations associated with each disease process. This article elucidates the goals in the management and treatment of this complex patient population.

How the Nurse Anesthetist Decides to Manage Perioperative Fluid Status

PURPOSE

To determine the factors that affect how nurse anesthetists in a county in Sweden decide how to manage perioperative fluid status.

DESIGN

A cross-sectional qualitative study was conducted at two surgical wards in a county hospital.

METHODS

Sixteen nurse anesthetists were interviewed to explore how nurse anesthetists assess patients' intraoperative fluid requirements and the subsequent measures adopted.

FINDING

Three categories emerged through content analysis: clinical criteria and the thought process that drives decision making, interdependence in decision making, and uncertainty in decision making.

CONCLUSIONS

This study revealed differences with regard to fluid management among nurse anesthetists in a county in Sweden. For the assessments and subsequent measures that are carried out to ensure optimal fluid therapy, more research is needed to provide evidence, and evidence-based guidelines need to be developed in Sweden.

From Pre-Existing Renal Failure to Perioperative Renal Protection: The Anesthesiologist's Dilemmas

CONTEXT

Pre-existing renal dysfunction presents specific features that anesthesiologists must deal with. Anesthesia and renal function are connected and can interfere with each other. Induced hypotension anesthesia and the toxic effects of anesthetic drugs can further deteriorate renal function.

EVIDENCE ACQUISITION

Decreased renal function can prolong anesthetic drug effects by decreased elimination of these drugs. Anesthesia can deteriorate renal function and decreased renal function can interfere with drug elimination leading to their prolonged effect. The anesthesiologist must understand all the physiological aspects of the patient, renal protection, and the relationships between anesthetic drugs and renal function. This review article aims to summarize these aspects.

RESULTS

Perioperative renal failure and renal protection is a crucial moment in clinical practice of every anesthesiologist.

CONCLUSIONS

Good knowledges for renal function remain a hallmark of daily practice of the anesthesiologist, considering renal function as an important determinant factor in anesthesia practice.

Acute renal injury after partial hepatectomy

Currently, partial hepatectomy is the treatment of choice for a wide variety of liver and biliary conditions. Among the possible complications of partial hepatectomy, acute kidney injury (AKI) should be considered as an important cause of increased morbidity and postoperative mortality. Difficulties in the data analysis related to postoperative AKI after liver resections are mainly due to the multiplicity of factors to be considered in the surgical patients, moreover, there is no consensus of the exact definition of AKI after liver resection in the literature, which hampers comparison and analysis of the scarce data published on the subject. Despite this multiplicity of risk factors for postoperative AKI after partial hepatectomy, there are main factors that clearly contribute to its occurrence. First factor relates to large blood losses with renal hypoperfusion during the operation, second factor relates to the occurrence of post-hepatectomy liver failure with consequent distributive circulatory changes and hepatorenal syndrome. Eventually, patients can have more than one factor contributing to post-operative AKI, and frequently these combinations of acute insults can be aggravated by sepsis or exposure to nephrotoxic drugs.

Peptidyl arginine deiminase-4-deficient mice are protected against kidney and liver injury after renal ischemia and reperfusion

We previously demonstrated that renal peptidyl arginine deiminase-4 (PAD4) is induced after renal ischemia and reperfusion (I/R) injury and exacerbates acute kidney injury (AKI) by increasing the renal tubular inflammatory response. Here, we tested whether genetic ablation of PAD4 attenuates renal injury and inflammation after I/R in mice. After renal I/R, PAD4 wild-type mice develop severe AKI with large increases in plasma creatinine, neutrophil infiltration, as well as significant renal tubular necrosis, apoptosis, and proinflammatory cytokine generation. In contrast, PAD4-deficient mice are protected against ischemic AKI with reduced real tubular neutrophil infiltration, renal tubular necrosis, and apoptosis. In addition, hepatic injury and inflammation observed in PAD4 wild-type mice after renal I/R are significantly attenuated in PAD4-deficient mice. We also show that increased renal tubular PAD4 expression after renal I/R is associated with translocation of PAD4 from the nucleus to the cytosol. Consistent with PAD4 cytosolic translocation, we show increased renal tubular cytosolic peptidyl-citrullination after ischemic AKI. Mechanistically, recombinant PAD4 treatment increased nuclear translocation of NF-κB in cultured human as well as murine proximal tubule cells that is inhibited by a PAD4 inhibitor (2-chloroamidine). Taken together, our studies further support the hypothesis that renal tubular PAD4 plays a critical role in renal I/R injury by increasing the renal tubular inflammatory response and neutrophil infiltration after renal I/R perhaps by interacting with the proinflammatory transcription factor NF-κB in the cytosol and promoting its nuclear translocation.

The effect of insulin-loaded linear poly(ethylene glycol)-brush-like poly(l-lysine) block copolymer on renal ischemia/reperfusion-induced lung injury through downregulating hypoxia-inducible factor

The aim of this study was to observe the therapeutic effect of insulin-loaded linear poly(ethylene glycol)-brush-like poly(l-lysine) block copolymer poly(ethylene glycol)-b-(poly(ethylenediamine l-glutamate)-g-poly(l-lysine)) (PEG-b-(PELG-g-PLL) on renal ischemia/reperfusion-induced lung injury through downregulating hypoxia-inducible factor (HIF) as compared to free insulin. Sprague Dawley rats were pretreated with 30 U/kg insulin or insulin/PEG-b-(PELG-g-PLL) complex, and then subjected to 45 minutes of ischemia and 24 hours of reperfusion. The blood and lungs were collected, the level of serum creatinine and blood urea nitrogen were measured, and the dry/wet lung ratios, the activity of superoxide dismutase and myeloperoxidase, the content of methane dicarboxylic aldehyde and tumor necrosis factor-α, and the expression of HIF-1α and vascular endothelial growth factor (VEGF) were measured in pulmonary tissues. Both insulin and insulin/PEG-b-(PELG-g-PLL) preconditioning improved the recovery of renal function, reduced pulmonary oxidative stress injury, restrained inflammatory damage, and downregulated the expression of HIF-1α and VEGF as compared to ischemia/reperfusion group, while insulin/PEG-b-(PELG-g-PLL) significantly improved this effect.

Acute kidney injury after open ventral hernia repair: an analysis of the 2005-2012 ACS-NSQIP datasets

PURPOSE

Acute kidney injury (AKI) is a serious postoperative complication, negatively impacting mortality rates, extending length of stay, and raising hospital costs. The purpose of this study was to examine AKI following open ventral hernia repair (OVHR) using a large, heterogeneous database to determine the incidence and identify risk factors for this complication.

METHODS

Using the 2005-2012 ACS-NSQIP database, patients undergoing open ventral hernia repair were identified by CPT codes. Patients with acute kidney injury within 30 days of surgery were compared to controls by multivariate logistic regression across preoperative and intraoperative characteristics.

RESULTS

Of 48,629 open ventral hernia repair patients identified in the dataset, AKI developed in 1.4% (681 patients). Multivariate logistic regression determined a number of factors associated with AKI. These include WHO Class III obesity (OR = 2.57, p < 0.001), history of cardiovascular disease (OR = 1.81, p < 0.001), diabetes (OR = 1.29, p = 0.028), hypoalbuminemia (OR = 1.42, p = 0.004), and chronic kidney disease (for a baseline GFR of 60-89 mL/min/1.73 m2, OR = 1.62, p = 0.001; for 30-59 mL/min/1.73 m2, OR = 2.25, p < 0.001; for 15-29 mL/min/1.73 m2, OR = 4.96, p < 0.001). Intraoperative factors include prolonged operative time (for ≥1 SD above the mean, OR = 1.68, p = 0.002; for ≥2SD above the mean, OR = 2.76, p < 0.001) and intraoperative transfusion (OR = 2.44, p < 0.001).

CONCLUSIONS

Patients with a history of obesity, chronic kidney disease, cardiovascular history, diabetes, and hypoalbuminemia are at increased risk for AKI when undergoing OVHR. Intraoperative variables such as prolonged operative times and blood transfusions may also suggest increased risk. Preoperative identification of patients with these characteristics and perioperative hemodynamic stabilization are important first steps to minimize this complication.

Perioperative risk factors for acute kidney injury after liver resection surgery: an historical cohort study

PURPOSE

This study aimed to identify the incidence and risk factors for acute kidney injury (AKI) after liver resection surgery and to clarify the relationship between postoperative AKI and outcome.

METHODS

We conducted a historical cohort study of patients who underwent liver resection surgery with sevoflurane anesthesia from January 2004 to October 2011. Acute kidney injury was diagnosed based on the Acute Kidney Injury Network classification within 72 hr after the surgery. Patient data, surgical and anesthetic data, and laboratory data were extracted manually from the patients' electronic charts. Multivariable logistic regression analysis was used to identify perioperative risk factors for postoperative AKI.

RESULTS

Acute kidney injury was diagnosed in 78 of 642 patients (12.1%; 95% confidence interval [CI]: 9.7 to 14.9). Multivariable analysis showed an independent association between postoperative AKI and preoperative estimated glomerular filtration rate (adjusted odds ratio [aOR] 0.74; 95% CI: 0.64 to 0.85), preoperative hypertension (aOR 2.10; 95% CI: 1.11 to 3.97), and intraoperative red blood cell transfusion (aOR 1.04; 95% CI: 1.01 to 1.07). Development of AKI within 72 hr after liver resection surgery was associated with increased hospital mortality, prolonged length of stay, and increased rates of mechanical ventilation, reintubation, and renal replacement therapy.

CONCLUSION

Perioperative risk factors for AKI after liver resection surgery are similar to those established for other surgical procedures. Further studies are needed to establish causality and to determine whether interventions on modifiable risk factors can reduce the incidence of postoperative AKI and improve patient outcome. This study was registered at the University Hospital Medical Information Network (UMIN) Center (UMIN 000008089).

Clinical conundrums and challenges during geriatric orthopedic emergency surgeries

Despite so many advancements and innovations in anesthetic techniques, expectations and challenges have also grown in plenty. Cardiac, pediatric, obstetric and neuro-anesthesia have perfectly developed to fulfill the desired needs of respective patient population. However, geriatric anesthesia has been shown a lesser interest in teaching and clinical practices over the years as compared with other anesthetic sub-specialties. The large growing geriatric population globally is also associated with an increase number of elderly patients presenting for orthopedic emergency surgeries. Orthopedic emergency surgery in geriatric population is not only a daunting clinical challenge but also has numerous socio-behavioral and economic ramifications. Decision making in anesthesia is largely influenced by the presence of co-morbidities, neuro-cognitive functions and the current socio-behavioral status. Pre-anesthetic evaluation and optimization are extremely important for a better surgical outcome but is limited by time constraints during emergency surgery. The current review aims to highlight comprehensively the various clinical, social, behavioral and psychological aspects during pre-anesthetic evaluation associated with emergency orthopedic surgery in geriatric population.

Adenosine receptors and renal ischaemia reperfusion injury

One of the frequent clinical complications that results in billions of dollars in healthcare costs annually in the United States is acute kidney injury (AKI). Ischaemia reperfusion (IR) injury is a major cause AKI. Unfortunately, no effective treatment or preventive measure for AKI exists. With increased surgical complexity coupled with increasing number of elderly, the incidence of AKI is becoming more frequent. Adenosine is a metabolic breakdown product of adenosine triphosphate (ATP) and contributes to the regulation of multiple physiological events. Extracellular adenosine activates four subtypes of adenosine receptors (AR) including A1 AR, A2 A AR, A2 B AR and A3 AR. In the kidney, adenosine regulates glomerular filtration rate, vascular tone, renin release and is an integrative part of tubular glomerular feedback signal to the afferent arterioles. In addition, each AR subtype powerfully modulates renal IR injury. The A1 AR activation protects against ischaemic insult by reducing apoptosis, necrosis and inflammation. Activation of A2 A AR protects against renal injury by modulating leucocyte-mediated inflammation as well as directly reducing renal tubular inflammation. Activation of A2 B AR acts via direct activation of renal parenchymal as well as renovascular receptors and is important in kidney preconditioning. Finally, activation of A3 AR exacerbates renal damage following renal IR injury while A3 AR antagonism attenuates renal damage following ischaemic insult. Latest body of research suggests that kidney AR modulation may be a promising approach to treat ischaemic AKI. This brief review focuses on the signalling pathways of adenosine in the kidney followed by the role for various AR modulations in protecting against ischaemic AKI.

Peptidyl arginine deiminase-4 activation exacerbates kidney ischemia-reperfusion injury

Peptidyl arginine deiminase (PAD)4 is a nuclear enzyme that catalyzes the posttranslational conversion of arginine residues to citrulline. Posttranslational protein citrullination has been implicated in several inflammatory autoimmune diseases, including rheumatoid arthritis, colitis, and multiple sclerosis. Here, we tested the hypothesis that PAD4 contributes to ischemic acute kidney injury (AKI) by exacerbating the inflammatory response after renal ischemia-reperfusion (I/R). Renal I/R injury in mice increased PAD4 activity as well as PAD4 expression in the mouse kidney. After 30 min of renal I/R, vehicle-treated mice developed severe AKI with large increases in plasma creatinine. In contrast, mice pretreated with PAD4 inhibitors (2-chloroamidine or streptonigrin) had significantly reduced renal I/R injury. Further supporting a critical role for PAD4 in generating ischemic AKI, mice pretreated with recombinant human PAD4 (rPAD4) protein and subjected to mild (20 min) renal I/R developed exacerbated ischemic AKI. Consistent with the hypothesis that PAD4 regulates renal tubular inflammation after I/R, mice treated with a PAD4 inhibitor had significantly reduced renal neutrophil chemotactic cytokine (macrophage inflammatory protein-2 and keratinocyte-derived cytokine) expression and had decreased neutrophil infiltration. Furthermore, mice treated with rPAD4 had significantly increased renal tubular macrophage inflammatory protein-2 and keratinocyte-derived cytokine expression as well as increased neutrophil infiltration and necrosis. Finally, cultured mouse kidney proximal tubules treated with rPAD4 had significantly increased proinflammatory chemokine expression compared with vehicle-treated cells. Taken together, our results suggest that PAD4 plays a critical role in renal I/R injury by increasing renal tubular inflammatory responses and neutrophil infiltration after renal I/R.

Predictors of acute kidney injury in geriatric patients undergoing total knee replacement surgery

BACKGROUND

Few studies have focused on patients' characteristics that affects acute kidney injury (AKI) after total knee replacement surgery (TKR).

OBJECTIVES

The primary objective of this retrospective study was to identify patients' characteristics associated with AKI after TKR.

PATIENTS AND METHODS

Between January 2008 and December 2009, 659 patients with a mean age of 67.1 years (range, 39-99) underwent TKA at Regional Hospital Knee and Hip Institute. Retrospective chart review was done to identify patients' characteristics that were associated with AKI after TKR. Logistic regression was used to evaluate AKI.

RESULTS

AKI occurred in 21.9% of patients. AKI risk decreased between 2008 and 2009 (odds ratio, 0.55; 95% CI, -0.37 to 0.82) but increased with age (P < 0.001), diabetes mellitus (DM), and angiotensin converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) use (OR, -1.6; 95% CI, -1.0 to 2.5; and OR, -1.5, 95% CI, -1.0 to 2.3, respectively). However, the effects of DM and ACEI/ARB use were not independent; when both were included in the regression model, neither was statistically significant, and both ORs were smaller than combined OR.

CONCLUSIONS

When examined separately, both DM and preoperative ACEI/ARB use increased the risk of AKI; however these factors were correlated and were not independent predictors of significantly increased risk. Patients with DM have higher tendency to develop AKI and hence, preoperative renal risk stratification should be done in all patients with DM.

Consumption of Cisatracurium in different age groups, using a closed loop computer controlled system

Background

We devised this study to quantify the effect of age on the consumption of cisatracurium under general anaesthesia, using a computer controlled closed loop infusion system. We further investigated this effect on, sufentanil and propofol consumption.

Methods

74 patients of physical status I and II, requiring general anaesthesia for elective abdominal surgery, were assigned to three groups. Patients in group 1 were aged from 20 to 45, group 2 were from 46 to 64, and group 3 above 65 years old. General Anesthesia was maintained with propofol and muscle paralysis was maintained using a closed-loop computer controlled infusion of cisatracurium. For analgesia, intermittent bolus of sufentanil 10 μg was given.

Results

Cisatracurium consumption in group 1, 2 and 3 were 1.8 ± 0.3, 1.6 ± 0.4 and 1.3 ± 0.4 μg/kg/min respectively. There was significant difference of cisatracurium consumption between group 1 and 3 (P = 0.002), and the consumption of cisatracurium in group 3 was less as compared with group 2 (P = 0.04). The average recovery index of patients in group 1, 2 and 3 were 8.8 ± 2.6, 11.5 ± 2.9 and 12.7 ± 2.5 minutes respectively. There were difference between group 1 and 2 (P = 0.02). As compared with group 1, the recovery index was still longer in group 3 (P = 0.001). Patients in group 1, 2 and 3 consumed an average sufentanil 0.4 ± 0.1, 0.4 ± 0.1 and 0.3 ± 0.1 μg/kg/hr, respectively. There were statistical significant between group 1 and 3 (P < 0.0001), and the same trend was found between group 2 and 3 (P = 0.03). The Consumption of propofol in group 1, 2 and 3 were 5.1 ± 0.4, 4.3 ± 0.6 and 3.1 ± 0.5 mg/kg/hr. The difference in the propofol consumption was found statistically significant when comparing between any two groups.

Conclusion

We concluded that the sensitivity of anesthetic agents increased with age. Less medication was required to achieve a desirable effect in older patients specially those above 65 years of age, and the drug effect was prolonged.

Trial registration

ClinicalTrials.gov Identifier: NCT01785446.

Volatile anesthetics and AKI: risks, mechanisms, and a potential therapeutic window

AKI is a major clinical problem with extremely high mortality and morbidity. Kidney hypoxia or ischemia-reperfusion injury inevitably occurs during surgery involving renal or aortic vascular occlusion and is one of the leading causes of perioperative AKI. Despite the growing incidence and tremendous clinical and financial burden of AKI, there is currently no effective therapy for this condition. The pathophysiology of AKI is orchestrated by renal tubular and endothelial cell necrosis and apoptosis, leukocyte infiltration, and the production and release of proinflammatory cytokines and reactive oxygen species. Effective management strategies require multimodal inhibition of these injury processes. Despite the past theoretical concerns about the nephrotoxic effects of several clinically utilized volatile anesthetics, recent studies suggest that modern halogenated volatile anesthetics induce potent anti-inflammatory, antinecrotic, and antiapoptotic effects that protect against ischemic AKI. Therefore, the renal protective properties of volatile anesthetics may provide clinically useful therapeutic intervention to treat and/or prevent perioperative AKI. In this review, we outline the history of volatile anesthetics and their effect on kidney function, briefly review the studies on volatile anesthetic-induced renal protection, and summarize the basic cellular mechanisms of volatile anesthetic-mediated protection against ischemic AKI.

miR-21 contributes to xenon-conferred amelioration of renal ischemia-reperfusion injury in mice

BACKGROUND

MicroRNAs participate in the regulation of numerous physiological and disease processes. The in vivo role of microRNAs in anesthetics-conferred organoprotection is unknown.

METHODS

Mice were exposed for 2 h to either 70% xenon, or 70% nitrogen, 24 h before the induction of renal ischemia-reperfusion injury. The role of microRNA, miR-21, in renal protection conferred by the delayed xenon preconditioning was examined using in vivo knockdown of miR-21 and analysis of miR-21 target pathways.

RESULTS

Xenon preconditioning provided morphologic and functional protection against renal ischemia-reperfusion injury (n = 6), characterized by attenuation of renal tubular damage, apoptosis, and oxidative stress. Xenon preconditioning significantly increased the expression of miR-21 in the mouse kidney. A locked nucleic acid-modified anti-miR-21, given before xenon preconditioning, knocked down miR-21 effectively, and exacerbated subsequent renal ischemia-reperfusion injury. Mice treated with anti-miR-21 and ischemia-reperfusion injury showed significantly higher serum creatinine than antiscrambled oligonucleotides-treated mice, 24 h after ischemia-reperfusion (1.37 ± 0.28 vs. 0.81 ± 0.14 mg/dl; n = 5; P < 0.05). Knockdown of miR-21 induced significant up-regulation of programmed cell death protein 4 and phosphatase and tensin homolog deleted on chromosome 10, two proapoptotic target effectors of miR-21, and resulted in significant down-regulation of phosphorylated protein kinase B and increased tubular cell apoptosis. In addition, xenon preconditioning up-regulated hypoxia-inducible factor-1α and its downstream effector vascular endothelial growth factor in a time-dependent manner. Knockdown of miR-21 resulted in a significant decrease of hypoxia-inducible factor-1α.

CONCLUSIONS

These results indicate that miR-21 contributes to the renoprotective effect of xenon preconditioning.

Selective deletion of the endothelial sphingosine-1-phosphate 1 receptor exacerbates kidney ischemia-reperfusion injury

The role for the endothelial sphingosine-1-phosphate 1 receptor (S1P1R) in acute kidney injury (AKI) remains unclear as germline endothelial S1P1R deletion is embryonically lethal. Here, we generated conditional endothelial S1P1R deficiency by crossing mice with floxed S1P1R with mice expressing a tamoxifen-inducible form of Cre recombinase under the transcriptional control of the platelet-derived growth factor-β gene. Mice with tamoxifen-induced deletion of endothelial S1P1R had increased renal tubular necrosis, inflammation, impaired vascular permeability as well as exacerbated renal tubular apoptosis after ischemic AKI compared to tamoxifen-treated wild type mice. Moreover, endothelial S1P1R deletion resulted in increased hepatic injury after ischemic AKI. As a potential mechanism for exacerbated renal injury, conditional endothelial S1P1R null mice had markedly reduced endothelial HSP27 expression compared to wild type mice. Cultured glomerular endothelial cells treated with a specific S1P1R antagonist (W146) for 3 days also showed reduced HSP27 expression compared to vehicle treated cells. Finally, mice treated with W146 for 3 days also showed reduced endothelial HSP27 expression as well as exacerbated renal and hepatic injury after ischemic AKI. Thus, our studies demonstrate a protective role for endothelial S1P1R against ischemic AKI most likely by regulating endothelial barrier integrity and endothelial HSP27 expression.

IL-11 is required for A1 adenosine receptor-mediated protection against ischemic AKI

A1 adenosine receptor activation ameliorates ischemic AKI through the induction of renal proximal tubular sphingosine kinase-1. However, systemic adverse effects may limit A1 adenosine receptor-based therapy for ischemic AKI, indicating a need to identify alternative therapeutic targets within this pathway. Here, we evaluated the function of renal proximal tubular IL-11, a clinically approved hematopoietic cytokine, in A1 adenosine receptor-mediated induction of sphingosine kinase-1 and renal protection. Treatment of human proximal tubule epithelial (HK-2) cells with a selective A1 adenosine receptor agonist, chloro-N(6)-cyclopentyladenosine (CCPA), induced the expression of IL-11 mRNA and protein in an extracellular signal-regulated kinase-dependent manner, and administration of CCPA in mice induced renal synthesis of IL-11. Pretreatment with CCPA protected against renal ischemia-reperfusion injury in wild-type mice, but not in IL-11 receptor-deficient mice. Administration of an IL-11-neutralizing antibody abolished the renal protection provided by CCPA. Similarly, CCPA did not induce renal IL-11 expression or protect against renal ischemia-reperfusion injury in mice lacking the renal proximal tubular A1 adenosine receptor. Finally, treatment with CCPA induced sphingosine kinase-1 in HK-2 cells and wild-type mice, but not in IL-11 receptor-deficient or renal proximal tubule A1 adenosine receptor-deficient mice. Taken together, these results suggest that induction of renal proximal tubule IL-11 is a critical intermediary in A1 adenosine receptor-mediated renal protection that warrants investigation as a novel therapeutic target for the treatment of ischemic AKI.

The volatile anesthetic isoflurane induces ecto-5'-nucleotidase (CD73) to protect against renal ischemia and reperfusion injury

The volatile anesthetic isoflurane protects against renal ischemia and reperfusion injury by releasing renal tubular TGF-β1. Since adenosine is a powerful cytoprotective molecule, we tested whether TGF-β1 generated by isoflurane induces renal tubular ecto-5′-nucleotidase (CD73) and adenosine to protect against renal ischemia and reperfusion injury. Isoflurane induced new CD73 synthesis and increased adenosine generation in cultured kidney proximal tubule cells and in mouse kidney. Moreover, a TGF-β1 neutralizing antibody prevented isoflurane-mediated induction of CD73 activity. Mice anesthetized with isoflurane after renal ischemia and reperfusion had significantly reduced plasma creatinine and decreased renal tubular necrosis, neutrophil infiltration and apoptosis compared to pentobarbital-anesthetized mice. Isoflurane failed to protect against renal ischemia and reperfusion injury in CD73 deficient mice, in mice pretreated with a selective CD73 inhibitor or mice treated with an adenosine receptor antagonist. The TGF-β1 neutralizing antibody or the CD73 inhibitor attenuated isoflurane-mediated protection against HK-2 cell apoptosis. Thus, isoflurane causes TGF-β1-dependent induction of renal tubular CD73 and adenosine generation to protect against renal ischemia and reperfusion injury. Modulation of this pathway may have important therapeutic implications to reduce morbidity and mortality arising from ischemic acute kidney injury.

Renalase protects against ischemic AKI

Elevated levels of plasma catecholamines accompany ischemic AKI, possibly contributing the inflammatory response. Renalase, an amine oxidase secreted by the proximal tubule, degrades circulating catecholamines and reduces myocardial necrosis, suggesting that it may protect against renal ischemia reperfusion injury. Here, mice subjected to renal ischemia reperfusion injury had significantly lower levels of renalase in the plasma and kidney compared with sham-operated mice. Consistent with this, plasma NE levels increased significantly after renal ischemia reperfusion injury. Furthermore, renal tubular inflammation, necrosis, and apoptosis were more severe and plasma catecholamine levels were higher in renalase-deficient mice subjected to renal ischemia reperfusion compared with wild-type mice. Administration of recombinant human renalase reduced plasma catecholamine levels and ameliorated ischemic AKI in wild-type mice. Taken together, these data suggest that renalase protects against ischemic AKI by reducing renal tubular necrosis, apoptosis, and inflammation, and that plasma renalase might be a biomarker for AKI. Recombinant renalase therapy may have potential for the prevention and treatment of AKI.

Postoperative adverse outcomes in surgical patients with dementia: a retrospective cohort study

BACKGROUND

Dementia patients often present with coexisting medical conditions and potentially face higher risk of complications during hospitalization. Because the general features of postoperative adverse outcomes among surgical patients with dementia are unknown, we conducted a nationwide, retrospective cohort study to characterize surgical complications among dementia patients compared with sex- and age-matched nondementia controls.

METHODS

Reimbursement claims from the Taiwan National Health Insurance Research Database were studied. A total of 18,923 surgical patients were enrolled with preoperative diagnosis of dementia for 207,693 persons aged 60 years or older who received inpatient major surgeries between 2004 and 2007. Their preoperative comorbidities were adjusted and risks for major surgical complications were analyzed.

RESULTS

Dementia patients who underwent surgery had a significantly higher overall postoperative complication rate, adjusted odds ratio (OR) 1.79 (95 % confidence interval [CI] 1.72-1.86), with higher medical resources use, and in-hospital expenditures. Compared with controls, dementia patients had a higher incidence of certain postoperative complications that are less likely to be identified in their initial stage, such as: acute renal failure, OR = 1.32 (1.19-1.47); pneumonia, OR = 2.18 (2.06-2.31); septicemia, OR = 1.8 (1.69-1.92); stroke, OR = 1.51 (1.43-1.6); and urinary tract infection, OR = 1.62 (1.5-1.74).

CONCLUSIONS

These findings have specific implications for postoperative care of dementia patients regarding complications that are difficult to diagnose in their initial stages. Acute renal failure, pneumonia, septicemia, stroke, and urinary tract infection are the top priorities for prevention, early recognition, and intervention of postoperative complications among surgical patients with dementia. Further efforts are needed to determine specific protocols for health care teams serving this population.

Paneth cell-mediated multiorgan dysfunction after acute kidney injury

Acute kidney injury (AKI) is frequently complicated by extrarenal multiorgan injury, including intestinal and hepatic dysfunction. In this study, we hypothesized that a discrete intestinal source of proinflammatory mediators drives multiorgan injury in response to AKI. After induction of AKI in mice by renal ischemia-reperfusion or bilateral nephrectomy, small intestinal Paneth cells increased the synthesis and release of IL-17A in conjunction with severe intestinal apoptosis and inflammation. We also detected significantly increased IL-17A in portal and systemic circulation after AKI. Intestinal macrophages appear to transport released Paneth cell granule constituents induced by AKI, away from the base of the crypts into the liver. Genetic or pharmacologic depletion of Paneth cells decreased small intestinal IL-17A secretion and plasma IL-17A levels significantly and attenuated intestinal, hepatic, and renal injury after AKI. Similarly, portal delivery of IL-17A in macrophage-depleted mice decreased markedly. In addition, intestinal, hepatic, and renal injury following AKI was attenuated without affecting intestinal IL-17A generation. In conclusion, AKI induces IL-17A synthesis and secretion by Paneth cells to initiate intestinal and hepatic injury by hepatic and systemic delivery of IL-17A by macrophages. Modulation of Paneth cell dysregulation may have therapeutic implications by reducing systemic complications arising from AKI.

Preoperative geriatric assessment: comprehensive, multidisciplinary and proactive

With the changing global demographic pattern, our health care systems increasingly have to deal with a greater number of elderly patients, which consequently also takes its toll on our surgical services. The elderly are not simply older adults. They represent a heterogeneous branch of the population with specific physiological, psychological, functional and social issues that require individualised attention prior to surgery. Increased acknowledgement that chronological age alone is not an exclusion criterion, along with advances in surgical and anaesthetic techniques have today lead to decreased reluctance to deny the elderly surgical treatment. In order to ensure a safe perioperative period, we believe that a comprehensive, multidisciplinary and proactive preoperative assessment will be helpful to detect the multiple risk factors and comorbidities common in older patients, to assess functional status and simultaneously allow room for early preoperative interventions and planning of the intra- and postoperative period. In this review we outline the currently available preoperative geriatric risk assessment tools and provide an insight on how a comprehensive, multidisciplinary and proactive approach can help improve perioperative outcome.

Interleukin-11 protects against renal ischemia and reperfusion injury

Renal ischemia reperfusion (IR) injury causes renal tubular necrosis, apoptosis, and inflammation leading to acute and chronic kidney dysfunction. IL-11 is a multifunctional hematopoietic cytokine clinically approved to treat chemotherapy-induced thrombocytopenia. Recent studies suggest that IL-11 also has potent antiapoptotic and antinecrotic properties. In this study, we tested the hypothesis that exogenous IL-11 protects against renal IR injury and determined the mechanisms involved in renal protection. Pretreatment with human recombinant IL-11 (HR IL-11) or with long-acting site-specific polyethylene glycol (PEG)-conjugated human IL-11 analog (PEGylated IL-11) produced partial but significant protection against renal IR injury in mice. In addition, HR IL-11 or PEGylated IL-11 given 30-60 min after IR also provided renal protection in mice. Significant reductions in renal tubular necrosis and neutrophil infiltration as well as tubular apoptosis were observed in mice treated with HR IL-11 or PEGylated IL-11. Furthermore, HR IL-11 or PEGylated IL-11 decreased both necrosis and apoptosis in human proximal tubule (HK-2) cells in culture. Mechanistically, IL-11 increased nuclear translocation of hypoxia-inducible factor-1α (HIF-1α) and induced sphingosine kinase-1 (SK1) expression and activity in HK-2 cells. Moreover, selective HIF-1α inhibitors blocked IL-11-mediated induction of SK1 in HK-2 cells. Finally, HR IL-11 or PEGylated IL-11 failed to protect against renal IR injury in SK1-deficient mice. Together, our data show powerful renal protective effects of exogenous IL-11 against IR injury by reducing necrosis, inflammation, and apoptosis through induction of SK1 via HIF-1α.

A1 adenosine receptor allosteric enhancer PD-81723 protects against renal ischemia-reperfusion injury

Activation of A(1) adenosine receptors (ARs) protects against renal ischemia-reperfusion (I/R) injury by reducing necrosis, apoptosis, and inflammation. However, extrarenal side effects (bradycardia, hypotension, and sedation) may limit A(1)AR agonist therapy for ischemic acute kidney injury. Here, we hypothesized that an allosteric enhancer for A(1)AR (PD-81723) protects against renal I/R injury without the undesirable side effects of systemic A(1)AR activation by potentiating the cytoprotective effects of renal adenosine generated locally by ischemia. Pretreatment with PD-81723 produced dose-dependent protection against renal I/R injury in A(1)AR wild-type mice but not in A(1)AR-deficient mice. Significant reductions in renal tubular necrosis, neutrophil infiltration, and inflammation as well as tubular apoptosis were observed in A(1)AR wild-type mice treated with PD-81723. Furthermore, PD-81723 decreased apoptotic cell death in human proximal tubule (HK-2) cells in culture, which was attenuated by a specific A(1)AR antagonist (8-cyclopentyl-1,3-dipropylxanthine). Mechanistically, PD-81723 induced sphingosine kinase (SK)1 mRNA and protein expression in HK-2 cells and in the mouse kidney. Supporting a critical role of SK1 in A(1)AR allosteric enhancer-mediated renal protection against renal I/R injury, PD-81723 failed to protect SK1-deficient mice against renal I/R injury. Finally, proximal tubule sphingosine-1-phosphate type 1 receptors (S1P(1)Rs) are critical for PD-81723-induced renal protection, as mice selectively deficient in renal proximal tubule S1P(1)Rs (S1P(1)R(flox/flox) PEPCK(Cre/-) mice) were not protected against renal I/R injury with PD-81723 treatment. Taken together, our experiments demonstrate potent renal protection with PD-81723 against I/R injury by reducing necrosis, inflammation, and apoptosis through the induction of renal tubular SK1 and activation of proximal tubule S1P(1)Rs. Our findings imply that selectively enhancing A(1)AR activation by locally produced renal adenosine may be a clinically useful therapeutic option to attenuate ischemic acute kidney injury without systemic side effects.

Proximal tubule sphingosine kinase-1 has a critical role in A1 adenosine receptor-mediated renal protection from ischemia

Renal ischemia reperfusion injury is a major cause of acute kidney injury. We previously found that renal A1 adenosine receptor (A1AR) activation attenuated multiple cell death pathways including necrosis, apoptosis and inflammation. Here, we tested whether induction of cytoprotective sphingosine kinase (SK)-1 and sphingosine-1 phosphate (S1P) synthesis might be the mechanism of protection. A selective A1AR agonist (CCPA) increased the synthesis of S1P and selectively induced SK-1 in mouse kidney and HK-2 cells. This agonist failed to protect SK1-knockout but protected SK2-knockout mice against renal ischemia reperfusion injury indicating a critical role of SK1 in A1AR-mediated renal protection. Inhibition of SK prevented A1AR-mediated defense against necrosis and apoptosis in HK-2 cells. A selective S1P1R antagonist (W146) and global in vivo gene knockdown of S1P1Rs with small interfering RNA completely abolished the renal protection provided by CCPA. Mice selectively deficient in renal proximal tubule S1P1Rs (S1P1Rflox/flox PEPCKCre/−) were not protected against renal ischemia reperfusion injury by CCPA. Mechanistically, CCPA increased nuclear translocation of hypoxia inducible factor-1α in HK-2 cells and selective hypoxia inducible factor-1α inhibition blocked A1AR-mediated induction of SK1. Thus, proximal tubule SK-1 has a critical role in A1AR-mediated protection against renal ischemia reperfusion injury.

Deciphering the mechanisms of the Na+/H+ exchanger-3 regulation in organ dysfunction

The Na+/H+ exchanger-3 (NHE3) belongs to the mammalian NHE protein family and catalyzes the electro-neutral exchange of extracellular sodium for intracellular proton across cellular membranes. Its transport function is of essential importance for the maintenance of the body's salt and water homeostasis as well as acid-base balance. Indeed, NHE3 activity is finely regulated by a variety of stimuli, both acutely and chronically, and its transport function is fundamental for a multiplicity of severe and world-wide infection-pathological conditions. This review aims to provide a concise overview of NHE3 physiology and discusses the role of NHE3 in clinical conditions of prominent importance, specifically in hypertension, diabetic nephropathy, heart failure, acute kidney injury, and diarrhea. Study of NHE3 function in models of these diseases has contributed to the deciphering of mechanisms that control the delicate ion balance disrupted in these disorders. The majority of the findings indicate that NHE3 transport function is activated before the onset of hypertension and inhibited thereafter; NHE3 transport function is also upregulated in diabetic nephropathy and heart failure, while it is reported to be downregulated in acute kidney injury and in diarrhea. The molecular mechanisms activated during these pathological conditions to regulate NHE3 transport function are examined with the aim of linking NHE3 dysfunction to the analyzed clinical disorders.