Renal replacement therapy for the patient with acute traumatic brain injury and severe acute kidney injury

Severe traumatic brain injury and acute kidney injury patients: factors associated with in-hospital mortality and unfavorable outcomes

OBJECTIVE

The purpose of this study was to identify the occurrence of AKI, and factors associated with in-hospital mortality and unfavorable outcomes in patients with severe traumatic brain injury (TBI) and acute kidney injury (AKI) severity.

METHOD

A retrospective cohort study which analyzed data with severe TBI between 2013 and 2017. We examined demographic and clinical information, and outcome by in-hospital mortality, and the Glasgow Outcome Scale six months after TBI. We associated factors to in-hospital mortality and unfavorable outcome in severe TBI and AKI with an association test.

RESULTS

A total of 219 patients were selected, 39.3% had an AKI, and several factors associated with AKI occurrence after severe TBI. Stage 2 or 3 of AKI (OR 12.489; 95% CI = 4.45-37.94) were independent risk for both outcomes in multivariable models, severity injury by the New Trauma Injury Severity Score (OR 0.97; 95% CI = 0.96-0.99) for mortality, and the New Injury Severity Score (OR1.07; 95% CI = 1.04-1.10) and Trauma and Injury Severity Score (OR = 0.98; 95% CI = 0.965-0.997) for unfavorable outcome.

CONCLUSION

The findings of our study confirmed that AKI severity and severity of injury was also related to increased mortality and unfavorable outcome after severe TBI.

Optimizing Mannitol Use in Managing Increased Intracranial Pressure: A Comprehensive Review of Recent Research and Clinical Experiences

Mannitol, derived from mannose sugar, is crucial in treating patients with elevated intracranial pressure (ICP). Its dehydrating properties at the cellular and tissue levels increase plasma osmotic pressure, which is studied for its potential to reduce ICP through osmotic diuresis. While clinical guidelines support mannitol use in these cases, the best approach for its application continues to be debated. Important aspects needing further investigation include: 1) bolus administration versus continuous infusion, 2) ICP-based dosing versus scheduled bolus, 3) identifying the optimal infusion rate, 4) determining the appropriate dosage, 5) establishing fluid replacement plans for urinary loss, and 6) selecting monitoring techniques and thresholds to assess effectiveness and ensure safety. Due to the lack of adequate high-quality prospective research data, a comprehensive review of recent studies and clinical trials is crucial. This assessment aims to bridge the knowledge gap, improve understanding of effective mannitol use in elevated ICP patients, and provide insights for future research. In conclusion, this review aspires to contribute to the ongoing discourse on mannitol application. By integrating the latest findings, this review will offer valuable insights into the function of mannitol in decreasing ICP, thereby informing better therapeutic approaches and enhancing patient outcomes.

Dialysis Disequilibrium Syndrome and Intracranial Pressure Fluctuations in Neurosurgical Patients Undergoing Renal Replacement Therapy: Systematic Review and Pooled Analysis

BACKGROUND

Dialysis disequilibrium syndrome is a rare, well-known, potentially life-threatening complication of renal replacement therapy (RRT), often involving cerebral edema and increased intracranial pressure (ICP). However, the impact of RRT on ICP and rate of dialysis disequilibrium syndrome in neurosurgical patients have not been systematically assessed.

METHODS

In February 2022, a systematic review following PRISMA guidelines was conducted using various combinations of 9 keywords in the MEDLINE database. Eleven papers were selected. Individual patient data were extracted, pooled, and analyzed.

RESULTS

Fifty-eight patients, 44 men and 14 women with a mean age of 48 years (6-78 years), were analyzed. Neurosurgical conditions included the following: spontaneous intracranial hemorrhage (n = 27), traumatic brain injury (n = 16), ischemic stroke/anoxic brain injury (n = 6), intracranial tumor (n = 6), and others (n = 3). Neurosurgical interventions included the following: craniotomy/craniectomy (n = 23), external ventricular drain or ICP monitor placement (n = 16), and burr hole or twist drill craniostomy (n = 4). Intermittent dialysis was used in 33 patients, continuous RRT in 20, and a combination thereof in 4. During RRT, ICP increased in 35 patients (60.3%), remained unchanged in 20, and decreased in 3. Thirty-four patients (65.4%) died. Intermittent dialysis was associated with increased ICP (73% vs. 37.5%, P = 0.01) and mortality (75% vs. 39.1%, P = 0.01).

CONCLUSIONS

In neurosurgical patients, ICP increases during RRT are common, affecting up to 60%, and potentially life-threatening, with mortality rates as high as 65%. The use of a continuous rather than intermittent RRT technique may reduce the risk of this complication. Prospective studies are warranted.

Changes in total and segmental extracellular and intracellular volumes with hypotension during hemodialysis measured with bioimpedance spectroscopy

BACKGROUND

Bioelectrical impedance analysis (BIA) devices have been advocated to guide volume management in hemodialysis (HD) patients. We hypothesized that understanding the dynamics of fluid shifts in different body segments may provide additional insight on preventive measures to reduce the risk of intradialytic hypotension.

METHODS

A prospective observational study was conducted among 42 HD patients at risk of hypotension who were admitted as emergencies inpatient.

RESULTS

A total of 191 BIA measurements were made during the 42 HD sessions, and hypotension occurred during 52 measurements (27%). The extracellular water (ECW) to intracellular water ratio (EIR) was measured in different body segments and declined significantly only in the non-access arm with increasing HD session duration (β = -0.04; 95% confidence interval (CI): -0.05 to -0.03, p < 0.01). There was no significant association between EIR and hypotension with respect to the different body segments. Only pre-HD N-terminal-pro b-type natriuretic peptide was significantly associated with hypotension (β = 0.20, 95% CI: 0.04 to 0.89, p = 0.04). There was no association between relative blood volume monitoring change and EIR.

CONCLUSION

In summary, we found that segmental BIA during HD was unable to detect or predict hypotension during dialysis. Although BIA is able to provide information about ECW and guide clinical assessment of volume in HD patients prior to dialysis, our findings did not suggest the use of serial measurements of changes in EIR in different body segments during HD provided sufficient information to predict intradialytic hypotension. Similarly, changes in EIR did not provide information on changes in plasma volume that could potentially trigger interventions to prevent or reduce intra-dialytic hypotension.

Excessive elevation of serum phosphate during tumor lysis syndrome: Lessons from a particularly challenging case

Burkitt’s lymphoma is a common cause of tumor lysis syndrome (TLS) and, in the era of aggressive utilization of prophylactic allopurinol and recombinant uricase enzyme, nephrologists are increasingly witnessing monovalent or divalent cation abnormalities without marked uric acid elevation. An 18-year-old male received his 1^st cycle of intensive chemotherapy for Burkitt’s lymphoma and developed TLS as defined by the Cairo Bishop criteria. Lactate dehydrogenase peaked at 9,105 U/L (range: 130 – 250) and was accompanied by acute kidney injury, including serum creatinine 2.2 mg/dL on the 4^th day with oliguria, hyperkalemia, extreme hyperphosphatemia (21.4 mg/dL), hypermagnesemia, and hypocalcemia. Renal replacement therapy decision was made based on life-threatening electrolyte disturbances. The competing necessity to effectively control hyperphosphatemia and avoid the complication of dialysis disequilibrium syndrome prompted us to perform an initial intermittent hemodialysis with simultaneous intravenous mannitol administration, followed by continuous hemodialysis to manage the continued production of phosphorus from cell lysis. Osmotic stability during the therapy session was affirmatively demonstrated (322, 319 mOsm/kg, respectively). The patient showed excellent tolerance for these therapies and eventually recovered renal function as demonstrated during follow-up visits.

Therapeutic hypernatremia management during continuous renal replacement therapy with elevated intracranial pressures and respiratory failure

Cerebral edema and elevated intracranial pressure (ICP) are common complications of acute brain injury. Hypertonic solutions are routinely used in acute brain injury as effective osmotic agents to lower ICP by increasing the extracellular fluid tonicity. Acute kidney injury in a patient with traumatic brain injury and elevated ICP requiring renal replacement therapy represents a significant therapeutic challenge due to an increased risk of cerebral edema associated with intermittent conventional hemodialysis. Therefore, continuous renal replacement therapy (CRRT) has emerged as the preferred modality of therapy in this patient population. We present our current treatment approach, with demonstrative case vignette illustrations, utilizing hypertonic saline protocols (3% sodium-chloride or, with coexisting severe combined metabolic and respiratory acidosis, with 4.2% sodium-bicarbonate) in conjunction with the CRRT platform, to induce controlled hypernatremia of approximately 155 mEq/L in hemodynamically unstable patients with acute kidney injury and elevated ICP due to acute brain injury. Rationale, mechanism of activation, benefits and potential pitfalls of the therapy are reviewed. The impact of hypertonic citrate solution during regional citrate anticoagulation is specifically discussed. Maintaining plasma hypertonicity in the setting of increased ICP and acute kidney injury could prevent the worsening of ICP during renal replacement therapy by minimizing the osmotic gradient across the blood-brain barrier and maximizing cardiovascular stability.

Factors Associated with Early Mortality in Critically Ill Patients Following the Initiation of Continuous Renal Replacement Therapy

Continuous renal replacement therapy (CRRT) is an important modality to support critically ill patients, and the need for CRRT treatment has been increasing. However, CRRT management is costly, and the associated resources are limited. Thus, it remains challenging to identify patients that are likely to have a poor outcome, despite active treatment with CRRT. We sought to elucidate the factors associated with early mortality after CRRT initiation. We analyzed 240 patients who initiated CRRT at an academic medical center between September 2016 and January 2018. We compared baseline characteristics between patients who died within seven days of initiating CRRT (early mortality), and those that survived more than seven days beyond the initiation of CRRT. Of the patients assessed, 130 (54.2%) died within seven days of CRRT initiation. Multivariate logistic regression models revealed that low mean arterial pressure, low arterial pH, and high Sequential Organ Failure Assessment score before CRRT initiation were significantly associated with increased early mortality in patients requiring CRRT. In conclusion, the mortality within seven days following CRRT initiation was very high in this study. We identified several factors that are associated with early mortality in patients undergoing CRRT, which may be useful in predicting early outcomes, despite active treatment with CRRT.

Changing the hemodialysis prescription for hemodialysis patients with subdural and intracranial hemorrhage

Although continuous modalities of renal replacement therapy offer an advantage to the patient with compromised cerebral perfusion and intracranial hypertension, they are generally limited to the intensive care unit setting. Many hemodialysis patients admitted with strokes and subdural hematoma are managed on general wards. As such, these patients are generally treated by intermittent hemodialysis, and their dialysis prescription should be altered to minimize changes in serum osmolality, and fall in blood pressure during dialysis. Such patients require more frequent but shorter dialysis sessions, using minimally bioincompatible small surface area dialyzers with lower blood flows, in combination with higher sodium and cooled dialysate. In patients at risk of intracranial hemorrhage and those with invasive intracranial monitoring, systemic anticoagulants should be avoided, choosing no anticoagulation protocols or regional anticoagulants.

The hemodynamic effects during sustained low-efficiency dialysis versus continuous veno-venous hemofiltration for uremic patients with brain hemorrhage: a crossover study

OBJECT

Hemodynamic instability occurs frequently during dialysis treatment and remains a significant cause of patient morbidity and mortality, especially in patients with brain hemorrhage. This study aims to compare the effects of hemodynamic parameters and intracranial pressure (ICP) between sustained low-efficiency dialysis (SLED) and continuous veno-venous hemofiltration (CVVH) in dialysis patients with brain hemorrhage.

METHODS

End-stage renal disease (ESRD) patients with brain hemorrhage undergoing ICP monitoring were enrolled. Patients were randomized to receive CVVH or SLED on the 1st day and were changed to the other modality on the 2nd day. The ultrafiltration rate was set at between 1.0 kg/8 hrs and 1.5 kg/8 hrs according to the patient's fluid status. The primary study end point was the change in hemodynamics and ICP during the dialytic periods. The secondary end point was the difference between cardiovascular peptides and oxidative and inflammatory assays.

RESULTS

Ten patients (6 women; mean age 59.9 ± 3.6 years) were analyzed. The stroke volume variation was higher with SLED than CVVH (generalized estimating equations method, p = 0.031). The ICP level increased after both SLED and CVVH (time effect, p = 0.003) without significant difference between modalities. The dialysis dose quantification after 8-hour dialysis was higher in SLED than CVVH (equivalent urea clearance by convection, 62.7 ± 4.4 vs 50.2 ± 3.9 ml/min; p = 0.002). Additionally, the endothelin-1 level increased after CVVH treatment (p = 0.019) but not SLED therapy.

CONCLUSIONS

With this controlled crossover study, the authors provide the pilot evidence that both SLED and CVVH display identical acute hemodynamic effects and increased ICP after dialysis in brain hemorrhage patients. CLINICAL TRIAL REGISTRATION NO.: NCT01781585 (ClinicalTrials.gov).

[Acute kidney injury]

Acute kidney injury plays a pivotal role in intensive care medicine and exerts crucial adverse effects on the course of the disease and overall prognosis of the critically ill patient. Intensive renal support, including initiation of earlier dialysis or maximal uremic toxin removal by higher dosage and frequency of renal replacement therapy, and individualized selection of modality were not able to decrease excessive mortality in this population. Systemic acute inflammation, mediated, at least in part, by cytokines, and not secondary uremic side effects, seems to have a major impact on nonrenal organ damage. Assessment of short-term outcome in critically ill patients who develop acute kidney injury may underestimate the true burden of disease. The overall survival at 5 years in patients discharged alive after severe acute kidney injury necessitating renal replacement therapy is only 20-30%, comparable to cancer patients. In addition, acute renal damage was identified as an independent risk factor for progression of chronic renal insufficiency. Current research focuses on strategies for the prevention of acute kidney injury and on the establishment of effective biomarkers for the early recognition and accurate diagnosis of subclinical renal damage.

Management of acute kidney injury in neurotrauma

Fortunately, the incidence of acute kidney injury (AKI) in neurotrauma is low and decreasing. Whereas the majority of AKI occurs in older patients with pre-existing chronic kidney disease, neurotrauma typically occurs in children and young adults with normal renal function. The development of outreach trauma teams has improved initial resuscitation, reducing both volume responsive and volume unresponsive cases of AKI. Most cases occur in the setting of multiple organ trauma with muscle injury, or patients who subsequently develop multiple organ failure. Once AKI has developed and renal replacement therapy is required, continuous modalities of renal replacement therapy offer an advantage to the patient with compromised cerebral perfusion and intracranial hypertension, by reducing the rate of change in serum urea, compared with standard intermittent therapies of hemodialysis and hemofiltration, thus minimizing abrupt changes in serum osmolality. Continuous hemodialysis and hemofiltration are better suited to maintain a normal or high serum sodium and thermal losses through the extracorporeal circuit, than peritoneal dialysis. Dialyzers should preferably be minimally bioincompatible and of a small surface area. In patients at risk of intracranial hemorrhage and those with invasive intracranial monitoring, systemic anticoagulants should either be avoided or regional anticoagulants should be used.

Continuous renal replacement therapy for refractory intracranial hypertension

INTRODUCTION

Little is known about the effects of hemodialysis on the injured brain, however; concern exists over the use of intermittent hemodialysis in patients with acute brain injury (ABI) due to its hemodynamic effects and increased intracranial pressure (ICP) associated with therapy. Continuous renal replacement therapy (CRRT) has become the preferred method of renal support in these patients though there is limited data to support its safety. Furthermore, exacerbations of cerebral edema have been reported. CRRT is an option for the treatment of hypervolemia and in theory may improve intracranial compliance. We report the case of a poly-trauma patient with severe traumatic brain injury (TBI) in which CRRT was implemented solely for refractory intracranial hypertension.

METHODS

A 28-year-old male was involved in a high-speed motor vehicle collision suffering a severe TBI and polytrauma. He required significant volume resuscitation. Intensive care unit course was complicated by shock, acute respiratory distress syndrome, ventilator associated pneumonia, and development of intracranial hypertension (IH). Data were collected by retrospective chart review.

RESULTS

Continuous hemofiltration was initiated for IH refractory to medical therapy. Within hours of initiation increase, ICP improved and normalized. Hemofiltration was safely discontinued after 48 h. Modified Rankin Score was 2 at 90 days.

CONCLUSION

Though unproven, CRRT may be beneficial in patients with IH due to gentle removal of fluid, solutes, and inflammatory cytokines. Given the limited data on safety of CRRT in patients with ABI, we encourage further reports.

Continuous renal replacement therapies in patients with acute neurological injury

Acute neurological injury may occur in patients with end-stage kidney disease on dialysis. Less frequently, acute kidney injury requiring renal dialytic support develops following acute neurological injury. Surrounding any site of neurological injury there is a penumbra of damage which is potentially reversible. To maximize full potential neurological recovery in patients requiring renal dialytic support, it is important that treatments do not themselves cause further cerebral ischemia. Standard intermittent hemodialysis is associated with cerebral swelling even in healthy outpatients and often with episodes of intradialytic hypotension. Continuous modes of renal replacement therapy have been shown to cause fewer surges in intracranial pressure and greater stability of cerebral perfusion pressure than standard intermittent techniques. In patients with acute neurological injury, renal replacement therapy should be carefully adapted to minimize cardiovascular instability and reduce the rate of change of serum osmolality.