Renal effects of norepinephrine-induced variations in mean arterial pressure after liver transplantation: A randomized cross-over trial

Vasopressors to treat postoperative hypotension after adult noncardiac, non-obstetric surgery: a systematic review

BACKGROUND

Postoperative hypotension is common after major surgery and is associated with patient harm. Vasopressors are commonly used to treat hypotension without clear evidence of benefit. We conducted a systematic review to better understand the use, impact, and rationale for vasopressor administration after noncardiac, non-obstetric surgery in adults.

METHODS

We conducted a prospectively registered systematic review. Cochrane CENTRAL, EMBASE, MEDBASE, and MEDLINE were searched for RCTs and cohort studies of adult patients receiving vasopressors after noncardiac, non-obstetric surgery. Study quality was critically appraised by two investigators. Findings from the review were synthesised, but formal meta-analysis was not performed because of significant variability in study populations and outcomes.

RESULTS

A total of 3201 articles were screened, of which seven RCTs, two prospective cohort studies, and 15 retrospective cohort studies were included in the analysis (24 in total). One study was graded as high quality, two as moderate quality, and the remaining 21 as low quality. Sixteen studies relied on clinical assessment alone to decide on therapeutic interventions. Vasodilation was the most common suggested physiological disturbance. The median proportion of patients receiving vasopressors was 42% (interquartile range: 11.5-74.7%). Norepinephrine was the most common vasopressor used.

CONCLUSIONS

The evidence supporting the use of vasopressors to treat postoperative hypotension is limited. Future research should focus on whether vasodilatation or other physiological disturbance is driving postoperative hypotension to allow rational decision-making.

Norepinephrine May Exacerbate Septic Acute Kidney Injury: A Narrative Review

Sepsis, the most serious complication of infection, occurs when a cascade of potentially life-threatening inflammatory responses is triggered. Potentially life-threatening septic shock is a complication of sepsis that occurs when hemodynamic instability occurs. Septic shock may cause organ failure, most commonly involving the kidneys. The pathophysiology and hemodynamic mechanisms of acute kidney injury in the case of sepsis or septic shock remain to be elucidated, but previous studies have suggested multiple possible mechanisms or the interplay of multiple mechanisms. Norepinephrine is used as the first-line vasopressor in the management of septic shock. Studies have reported different hemodynamic effects of norepinephrine on renal circulation, with some suggesting that it could possibly exacerbate acute kidney injury caused by septic shock. This narrative review briefly covers the updates on sepsis and septic shock regarding definitions, statistics, diagnosis, and management, with an explanation of the putative pathophysiological mechanisms and hemodynamic changes, as well as updated evidence. Sepsis-associated acute kidney injury remains a major burden on the healthcare system. This review aims to improve the real-world clinical understanding of the possible adverse outcomes of norepinephrine use in sepsis-associated acute kidney injury.

Higher Mean Arterial Pressure during Cardiopulmonary Bypass May Not Prevent Acute Kidney Injury in Elderly Patients Undergoing Cardiac Surgery

We aimed to evaluate the role of higher mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) in preventing development of acute kidney injury (AKI). Methods. We evaluated a population of elderly individuals >60 years of age undergoing CPB to find correlation of MAP during CPB with development of AKI after the surgery. Patients who experienced sustained low MAP during the CPB defined as that of <65 mmHg were compared with those that had sustained high MAP of >65 mmHg for their outcome with regard to AKI. The KDIGO criteria were used to define presence of acute kidney injury. Results. Of the total 92 patients, 50 were in the low-pressure group and 42 were in the high-pressure group. The MAP was 61.14 ± 5.54 mmHg in the low-pressure group and 68.97 ± 3.65 mmHg in the high-pressure group (p < 0.001). 13 (26%) in the low-pressure group and 17 (40.48%) in the high-pressure group developed AKI (p = 0.140). Male sex was associated with an increased incidence of cardiac surgery-associated AKI (p = 0.034). Conclusions. A higher MAP in the range of 65-75 mmHg during the cardiopulmonary bypass does not significantly prevent acute kidney injury in elderly patients undergoing cardiac valve surgery.

Acute kidney injury after liver transplantation, perioperative risk factors, and outcome: prospective observational study of 1681 patients (OLTx Study)

BACKGROUND

Acute kidney injury (AKI) represents a frequent complication after orthotopic liver transplantation (OLT). This study aimed to evaluate early postoperative AKI incidence during the first 72 h after OLT, perioperative risk factors, and AKI impact on survival.

METHODS

From January 2011 to December 2013) 1681 patients underwent OLT in 19 centers and were enrolled in this prospective cohort study.

RESULTS

According to RIFLE criteria, AKI occurred in 367 patients, 21.8% (R: 5.8%, I: 6.4%, F: 4.8%, L: 4.8%). Based on multivariate analysis, intraoperative risk factors for AKI were: administration of 5-10 RBCs (OR 1.8, 95%CI 1.3-2.7), dopamine use (OR 1.6, 95%CI 1.2-2.3), post-reperfusion syndrome (OR 1.5, 95%CI 1.0-2.3), surgical complications (OR 2.0, 95% CI 1.3-3.0), and cardiological complications (OR 2.2, 95%CI 1.2-4.0). Postoperative risk factors were: norepinephrine (OR 1.4, 95%CI 1.0-2.0), furosemide (OR 4.2, 95% CI 3.0-5.9), more than 10 RBCs transfusion, (OR 3.7, 95%CI 1.4-10.5), platelets administration (OR 1.6, 95% CI 1.1-2.4), fibrinogen administration (OR 3.0, 95%CI, 1.5-6.2), hepatic complications (OR 4.6, 95%CI 2.9-7.5), neurological complications (OR 2.4, 95%CI 1.5-3.7), and infectious complications (OR 2.7, 95%CI 1.8-4.3). NO-AKI patients' 5 years survival rate was higher than AKI patients (68.06, 95% CI 62.7-72.7 and 81.2, 95% CI 78.9-83.3, p< 0.001).

CONCLUSIONS

AKI still remains an important risk factor for morbidity and mortality after OLT. Further researches to develop new strategies aimed at preventing or minimizing post-OLT AKI are needed.

The effect of targeting Tie2 on hemorrhagic shock-induced renal perfusion disturbances in rats

BACKGROUND

Hemorrhagic shock is associated with acute kidney injury and increased mortality. Targeting the endothelial angiopoietin/Tie2 system, which regulates endothelial permeability, previously reduced hemorrhagic shock-induced vascular leakage. We hypothesized that as a consequence of vascular leakage, renal perfusion and function is impaired and that activating Tie2 restores renal perfusion and function.

METHODS

Rats underwent 1 h of hemorrhagic shock and were treated with either vasculotide or PBS as control, followed by fluid resuscitation for 4 h. Microcirculatory perfusion was measured in the renal cortex and cremaster muscle using contrast echography and intravital microscopy, respectively. Changes in the angiopoietin/Tie2 system and renal injury markers were measured in plasma and on protein and mRNA level in renal tissue. Renal edema formation was determined by wet/dry weight ratios and renal structure by histological analysis.

RESULTS

Hemorrhagic shock significantly decreased renal perfusion (240 ± 138 to 51 ± 40, p < 0.0001) and cremaster perfusion (12 ± 2 to 5 ± 2 perfused vessels, p < 0.0001) compared to baseline values. Fluid resuscitation partially restored both perfusion parameters, but both remained below baseline values (renal perfusion 120 ± 58, p = 0.08, cremaster perfusion 7 ± 2 perfused vessels, p < 0.0001 compared to baseline). Hemorrhagic shock increased circulating angiopoietin-1 (p < 0.0001), angiopoietin-2 (p < 0.0001) and soluble Tie2 (p = 0.05), of which angiopoietin-2 elevation was associated with renal edema formation (r = 0.81, p < 0.0001). Hemorrhagic shock induced renal injury, as assessed by increased levels of plasma neutrophil gelatinase-associated lipocalin (NGAL: p < 0.05), kidney injury marker-1 (KIM-1; p < 0.01) and creatinine (p < 0.05). Vasculotide did not improve renal perfusion (p > 0.9 at all time points) or reduce renal injury (NGAL p = 0.26, KIM-1 p = 0.78, creatinine p > 0.9, renal edema p = 0.08), but temporarily improved cremaster perfusion at 3 h following start of fluid resuscitation compared to untreated rats (resuscitation + 3 h: 11 ± 3 vs 8 ± 3 perfused vessels, p < 0.05).

CONCLUSION

Hemorrhagic shock-induced renal impairment cannot be restored by standard fluid resuscitation, nor by activation of Tie2. Future treatment strategies should focus on reducing angiopoietin-2 levels or on activating Tie2 via an alternative strategy.

Vasopressor Responsiveness Beyond Arterial Pressure: A Conceptual Systematic Review Using Venous Return Physiology

ABSTRACT

We performed a systematic review to investigate the effects of vasopressor-induced hemodynamic changes in adults with shock. We applied a physiological approach using the interacting domains of intravascular volume, heart pump performance, and vascular resistance to structure the interpretation of responses to vasopressors. We hypothesized that incorporating changes in determinants of cardiac output and vascular resistance better reflect the vasopressor responsiveness beyond mean arterial pressure alone.We identified 28 studies including 678 subjects in Pubmed, EMBASE, and CENTRAL databases.All studies demonstrated significant increases in mean arterial pressure (MAP) and systemic vascular resistance during vasopressor infusion. The calculated mean systemic filling pressure analogue increased (16 ± 3.3 mmHg to 18 ± 3.4 mmHg; P = 0.02) by vasopressors with variable effects on central venous pressure and the pump efficiency of the heart leading to heterogenous changes in cardiac output. Changes in the pressure gradient for venous return and cardiac output, scaled by the change in MAP, were positively correlated (r2 = 0.88, P < 0.001). Changes in the mean systemic filling pressure analogue and heart pump efficiency were negatively correlated (r2 = 0.57, P < 0.001) while no correlation was found between changes in MAP and heart pump efficiency.We conclude that hemodynamic changes induced by vasopressor therapy are inadequately represented by the change in MAP alone despite its common use as a clinical endpoint. The more comprehensive analysis applied in this review illustrates how vasopressor administration may be optimized.

Perioperative Renoprotection: General Mechanisms and Treatment Approaches

In the perioperative setting, acute kidney injury (AKI) is a frequent complication, and AKI itself is associated with adverse outcomes such as higher risk of chronic kidney disease and mortality. Various risk factors are associated with perioperative AKI, and identifying them is crucial to early interventions addressing modifiable risk and increasing monitoring for nonmodifiable risk. Different mechanisms are involved in the development of postoperative AKI, frequently picturing a multifactorial etiology. For these reasons, no single renoprotective strategy will be effective for all surgical patients, and efforts have been attempted to prevent kidney injury in different ways. Some renoprotective strategies and treatments have proven to be useful, some are no longer recommended because they are ineffective or even harmful, and some strategies are still under investigation to identify the best timing, setting, and patients for whom they could be beneficial. With this review, we aim to provide an overview of recent findings from studies examining epidemiology, risk factors, and mechanisms of perioperative AKI, as well as different renoprotective strategies and treatments presented in the literature.

Impact of Intraoperative Norepinephrine Support on Living Donor Liver Transplantation Outcomes: A Retrospective Cohort Study of 430 Children

Norepinephrine (NE) is often administered during the perioperative period of liver transplantation to address hemodynamic instability and to improve organ perfusion and oxygen supply. However, its role and safety profile have yet to be evaluated in pediatric living donor liver transplantation (LDLT). We hypothesized that intraoperative NE infusion might affect pediatric LDLT outcomes. A retrospective study of 430 pediatric patients (median [interquartile range] age, 7 [6.10] months; 189 [43.9%] female) receiving LDLT between 2014 and 2016 at Renji Hospital was conducted. We evaluated patient survival among recipients who received intraoperative NE infusion (NE group, 85 recipients) and those that did not (non-NE group, 345 recipients). The number of children aged over 24 months and weighing more than 10 kg in NE group was more than that in non-NE group. And children in NE group had longer operative time, longer anhepatic phase time and more fluid infusion. After multivariate regression analysis and propensity score regression adjusting for confounding factors to determine the influence of intraoperative NE infusion on patient survival, the NE group had a 169% more probability of dying. Although there was no difference in mean arterial pressure changes relative to the baseline between the two groups, we did observe increased heart rates in NE group compared with those of the non-NE group at anhepatic phase (P=0.025), neohepatic phase (P=0.012) and operation end phase (P=0.017) of the operation. In conclusion, intraoperative NE infusion was associated with a poorer prognosis for pediatric LDLT recipients. Therefore, we recommend the application of NE during pediatric LDLT should be carefully re-considered.

Renal function after out-of-hospital cardiac arrest; the influence of temperature management and coronary angiography, a post hoc study of the target temperature management trial

Background

To elucidate the incidence of acute kidney injury (AKI) after out-of-hospital cardiac arrest (OHCA) and to examine the impact of target temperature management (TTM) and early coronary angiography on renal function.

Methods

Post hoc analysis of the TTM trial, a multinational randomised controlled trial comparing target temperature of 33 °C versus 36 °C in patients with return of spontaneous circulation after OHCA. The impact of TTM and early angiography (within 6 h of OHCA) versus late or no angiography on the development of AKI during the 7-day period after OHCA was analysed. AKI was defined according to modified KDIGO criteria in patients surviving beyond day 2 after OHCA.

Results

Following exclusions, 853 of 939 patients enrolled in the main trial were analysed. Unadjusted analysis showed that significantly more patients in the 33 °C group had AKI compared to the 36 °C group [211/431 (49%) versus 170/422 (40%) p = 0.01], with a worse severity (p = 0.018). After multivariable adjustment, the difference was not significant (odds ratio 0.75, 95% confidence interval 0.54–1.06, p = 0.10].

Five hundred seventeen patients underwent early coronary angiography. Although the unadjusted analysis showed less AKI and less severe AKI in patients who underwent early angiography compared to patients with late or no angiography, in adjusted analyses, early angiography was not an independent risk factor for AKI (odds ratio 0.73, 95% confidence interval 0.50–1.05, p = 0.09).

Conclusions

In OHCA survivors, TTM at 33 °C compared to management at 36 °C did not show different rates of AKI and early angiography was not associated with an increased risk of AKI.

Trial registration

NCT01020916. Registered on www.ClinicalTrials.gov 26 November 2009 (main trial).

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2390-0) contains supplementary material, which is available to authorized users.

Abdominal Organ Transplantation: Noteworthy Literature in 2018

A PubMed search revealed 1382 articles on pancreatic transplantation, 781 on intestinal transplantation, more than 7200 on kidney transplantation, and more than 5500 on liver transplantation published between January 1, 2018, and December 31, 2018. After narrowing the list down to human studies, 436 pancreatic, 302 intestinal, 1920 liver, and more than 2000 kidney transplantation studies were screened for inclusion in this review.