New strategies to optimize renal haemodynamics

Tiny clue reveals the general trend: a bibliometric and visualized analysis of renal microcirculation

BACKGROUND

Renal microcirculation plays a pivotal role in kidney function by maintaining structural and functional integrity, facilitating oxygen and nutrient delivery, and waste removal. However, a thorough bibliometric analysis in this area remains lacking. Therefore, we aim to provide valuable insights through a bibliometric analysis of renal microcirculation literature using the Web of Science database.

METHODS

We collected renal microcirculation-related publications from the Web of Science database from January 01, 1990, to December 31, 2022. The co-authorship of authors, organizations, and countries/regions was analyzed with VOSviewer1.6.18. The co-occurrence of keywords and co-cited references were analyzed using CiteSpace6.1.R6 software to generate visualization maps. Additionally, burst detection was applied to keywords and cited references to forecast research hotspots and future trends.

RESULTS

Our search yielded 7462 publications, with the American Journal of Physiology-Renal Physiology contributing the most articles. The United States, Mayo Clinic, and Lerman Lilach O emerged with the highest publication count, indicating their active collaborations. 'Type 2 diabetes' was the most significant keyword cluster, and 'diabetic kidney disease' was the largest cluster of cited references. 'Cardiovascular outcome' and 'diabetic kidney diseases' were identified as keywords in their burst period over the past three years.

CONCLUSION

Our bibliometric analysis illuminates the contours of nephrology and microcirculation research, revealing a landscape ripe for challenges and the seeds of future scientific innovation. While the trends discerned from the literature emerging opportunities in diagnostic innovation, renal microcirculation research, and precision medicine interventions, their translation to clinical practice is anticipated to be a deliberate process.

Anesthesia and intensive care unit care in pediatric kidney transplantation: An international survey

BACKGROUND

Despite the high perioperative risk profile, international guidelines for anesthesia and intensive care unit (ICU) care in pediatric kidney transplantation do not exist. Optimizing hemodynamics can be challenging in these patients, while scientific data to guide decisions in hemodynamic monitoring, hemodynamic targets, and perioperative fluid management are lacking. The limited annual number of pediatric kidney transplantations, even in reference centers, necessitates the urge for international collaboration to share knowledge and develop research and guidelines. The aim of this study was to collect data on current perioperative anesthesia and ICU care practices in pediatric kidney transplantation.

METHODS

An international survey with an anonymized link was sent from a validated electronic data capture system (Castor). Inclusion criteria were: medical doctor in anesthesia, (ICU), or pediatric nephrology working in a pediatric kidney transplantation specialized center; and signed informed consent. Data were analyzed using descriptive statistics.

RESULTS

Thirty-three records were analyzed. Responders were anesthesiologists (58%), pediatric nephrologists (30%), and pediatric intensivists (12%), representing 13 countries worldwide. About half of the centers (48%) performed more than 10 pediatric kidney transplantations a year. Perioperative hemodynamic support was guided by intra-arterial blood pressure (88%), central venous pressure (CVP; 88%), and cardiac output (CO; 39%). The most variation was seen in the hemodynamic targets CVP and CO, fluid administration, and inotrope/vasopressor use. The protocolized use of furosemide (46%) and mannitol (61%) also varied between centers. Postoperative care for the youngest recipients occurred in the pediatric intensive care unit at all centers.

CONCLUSION

The results of this survey reveal a large variation in anesthesia and ICU care in pediatric kidney transplantation centers worldwide, particularly in CVP and CO targets, hemodynamic therapy, and the use of furosemide and mannitol. These data identify areas for further research and can be a starting point for international research collaboration and guideline development.

Dilemmas of Adopting Goal-Directed Perfusion in Extracorporeal Circulation: A Narrative Review

OBJECTIVE

Extracorporeal circulation (ECC) is generally based on standards established in the last decade. In recent years, a concept of perfusion management during ECC, goal-directed perfusion (GDP), has emerged to create optimal conditions for oxygen delivery and extraction, initiated by Rannuci et al. The aim of the present work was to determine whether the ECC procedure can truly be optimized with the current state of knowledge and understanding of human physiology.

METHODS

Discussed articles from 2017 to 2022 were selected from the MEDLINE (PubMed) database using the keywords "cardiopulmonary bypass" AND "cardiac surgery" AND "oxygen delivery" with the conditions of "clinical trial" OR "randomized controlled trial."

RESULTS

The concept of GDP is an attempt to reproduce the physiological conditions of tissue respiration during ECC. Published articles, also due to their retrospective nature, are based on standards and recommendations that do not fully fit the field of physiological circulation. There are still insufficient tools to assess the relationship between volemia, perfusion pressure, and pump performance. Limitations include indications for vasoactive drugs. Methodology has rarely taken into account the period of starting and stopping the heart-lung machine, the most pronounced periods of circulatory destabilization with reduced oxygen delivery.

CONCLUSIONS

Problems associated with ECC such as acute kidney injury, liver failure, vasoplegic syndrome, and others must await its resolution. The use of advanced monitoring technology and data engineering may allow the development of baseline hemodynamic models, which may make the ECC procedure more physiologic and thus improve the safety of the procedure.

Intraoperative hypotension and the risk of acute kidney injury following liver transplantation

BACKGROUND

Acute kidney injury (AKI) is a frequent adverse outcome following liver transplantation (LT) with a multifactorial etiology. It is critical to identify modifiable risk factors to mitigate the risk. One key area of interest is the role of intraoperative hypotension, which remains relatively unexplored in liver transplant cohorts.

METHODS

This was a retrospective observational cohort study of 1292 adult patients who underwent LT (between 2009 and 2019). Multivariable logistic regression analysis was used to explore the association between intraoperative hypotension, quantified by time duration (in min) under various mean arterial pressure (MAP) thresholds, and the primary outcome of early postoperative AKI according to the KDIGO criteria.

RESULTS

AKI occurred in 40% of patients and was independently associated with greater than 20 min spent below MAP thresholds of 55 mm Hg (adjusted OR = 1.866; 95% CI = 1.037-3.44; P = 0.041) and 50 mm Hg (adjusted OR = 1.801; 95% CI = 1.087-2.992; P = 0.023). Further sensitivity analyses demonstrated that the association between intraoperative hypotension and postoperative AKI was accentuated after restricting the analysis to patients with a normal preoperative renal function.

CONCLUSIONS

Prolonged (>20 min) intraoperative hypotension (below a MAP of 55 mm Hg) was independently associated with AKI following LT, after adjusting for several known confounders.

Risk factors associated with acute kidney injury in a pediatric intensive care unit in Addis Ababa Ethiopia: case-control study

BACKGROUND

Acute kidney injury (AKI) is a serious health problem in critically ill children. It is associated with poor treatment outcomes and high morbidity and mortality rates. Globally, one in three critically ill children suffers from acute kidney injury. However, limited data are available in Africa, particularly Ethiopia, which highlighting the risk factors related to acute kidney injury. Therefore, this study aimed to identify the risk factors associated with acute kidney injury among critically ill children admitted to the pediatric intensive care unit (PICU) at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia.

METHODS

A facility-based unmatched case-control study was carried out on 253 (85 cases and 168 controls) critically ill children admitted to the pediatric intensive care unit from January 2011 to December 2021. Participants were selected using a systematic random sampling technique for the control group and all cases consecutively. Data were collected using a structured checklist. Data were entered using Epi data version 4.6 and analyzed using SPSS version 25. Multivariable analysis was carried out using the adjusted odds ratio (aOR) with a 95% confidence interval (CI) to identify associated factors with acute kidney injury. Statistical significance was set at P < 0.05.

RESULTS

The median age of the participants was two years. Approximately 55.6% of cases and 53.1% of controls were females. The diagnosis of hypertension (aOR = 5.36; 95% CI: 2.06-13.93), shock (aOR = 3.88, 95% CI: 1.85-8.12), exposure to nephrotoxic drugs (aOR = 4.09; 95% CI: 1. 45- 11.59), sepsis or infection aOR = 3.36; 95% CI: 1.42-7.99), nephritic syndrome (aOR = 2.97; 95% CI:1.19, 7.43), and use of mechanical ventilation aOR = 2.25, 95% CI: 1.12, 4.51) were significantly associated factors with acute kidney injury.

CONCLUSION

The diagnosis of sepsis or infection, hypertension, shock, nephrotoxic drugs, demand for mechanical ventilation support, and nephritic syndrome increased the risk of AKI among critically ill children. Multiple risk factors for AKI are associated with illness and severity. All measures that ensure adequate renal perfusion must be taken in critically ill children with identified risk factors to prevent the development of AKI.

The blood pressure targets in sepsis patients with acute kidney injury: An observational cohort study of multiple ICUs

Background

The maintenance of blood pressure is pivotal in preventing sepsis with acute kidney injury (AKI). Especially in sepsis patients treated with vasopressors. The optimal the blood pressure has been controversial to maintain renal perfusion. This study aims to explore the blood pressure target in sepsis with AKI.

Methods

We retrieved patient data from the MIMIC IV and eICU databases. The Lasso regression model was used to identify the relationship between blood pressure and sepsis in patients with AKI and remove collinearity among variables. Generalized additive models were used to estimate the blood pressure range in patients with sepsis with AKI. Statistical methods such as multivariable logistic regression, propensity score analysis, inversion probability-weighting, and doubly robust model estimation were used to verify the target blood pressure for patients with sepsis and AKI.

Results

In total, 17874 patients with sepsis were included in this study. the incidence of AKI may be related to the level of mean article pressure (MAP) and diastolic blood pressure (DBP) in sepsis patients. The range of MAPs and DBPs may be 65-73 mmHg and 50-60 mmHg in AKI patients without hypertension. The range of MAPs and DBPs may be 70-80 mmHg and 54-62 mmHg in AKI patients with hypertension. The prognosis of sepsis with AKI was unaffected by MAP or DBP. Systolic blood pressure is not associated with sepsis in patients with AKI.

Conclusions

To ensure renal perfusion, AKI patients with hypertension may require a higher MAP [70-80] versus (65-73), mmHg] and DBP [(54-62) vs (50-60), mmHg] than patients without hypertension.

Intrarenal Doppler approaches in hemodynamics: A major application in critical care

The treatment of severe cases usually requires multimodality hemodynamic monitoring approaches, particularly for tissue and organ perfusion tracking. Currently, only a few studies have investigated renal perfusion status at the bedside. Ultrasound has become increasingly utilized to guide the hemodynamic management of severe patients. Similarly, intrarenal Doppler (IRD) is widely used to assess renal perfusion from both the intrarenal artery and vein perspectives. The renal resistive index (RRI), which reflects the renal arterial blood flow profile, is often applied to predict the reversibility of renal dysfunction and to titrate hemodynamic support. Intrarenal venous flow (IRVF) patterns and the renal venous stasis index (RVSI), which reflects the intrarenal vein blood flow profile, are now being used to assess intravenous congestion. They may also be useful in predicting the risk of acute kidney injury and avoiding fluid overload. IRD can provide diverse and supplemental information on renal perfusion and may help to establish the early diagnosis in severe patients. This review focused on the specific operational methods, influencing factors, and applications of IRD in hemodynamics.

Relevant Equine Renal Anatomy, Physiology, and Mechanisms of Acute Kidney Injury: A Review

Regulation of renal blood flow is by both extrinsic and intrinsic systems. Intrinsic regulation occurs via the afferent and efferent arterioles and tubuloglomerular feedback mechanisms with activation of the juxtaglomerular apparatus. Mechanisms of acute kidney injury are frequently associated with changes in renal blood flow. Acute tubular necrosis and apoptosis are common in horses following ischemic or toxic insults and in sepsis-associated acute kidney injury. Sepsis-associated renal injury often has a complex mechanism of disease involving both functional and obstructive changes in intrarenal circulation. Acute interstitial nephritis may occur following Leptospira sp infection or can be secondary to tubular necrosis.

Acute Kidney Injury and Renal Failure in Horses

Nephrotoxic and hemodynamically mediated disorders are the most common causes of acute renal failure (ARF) in horses and foals. Leptospira spp. is the most common infectious cause of ARF. Initial treatments for ARF include elimination of nephrotoxic drugs, correction of predisposing disorders, and fluid therapy to promote diuresis. Horses and foals with polyuric ARF often have a good prognosis, while those with oliguric or anuric ARF have a guarded to poor prognosis. When fluid therapy is unsuccessful in improving urine production, various drugs treatments have been used in an attempt to increase urine production, but none are consistently effective in converting oliguria to polyuria.

Perioperative anesthesia care for the pediatric patient undergoing a kidney transplantation: An educational review

Living-donor kidney transplantation is the first choice therapy for children with end-stage renal disease and shows good long-term outcome. Etiology of renal failure, co-morbidities, and hemodynamic effects, due to donor-recipient size mismatch, differs significantly from those in adult patients. Despite the complexities related to both patient and surgery, there is a lack of evidence-based anesthesia guidelines for pediatric kidney transplantation. This educational review summarizes the pathophysiological changes to consider and suggests recommendations for perioperative anesthesia care, based on recent research papers.