Autonomic dysfunction following traumatic brain injury: translational insights.

Although there is a substantial amount of research on the neurological consequences of traumatic brain injury (TBI), there is a knowledge gap regarding the relationship between TBI and the pathophysiology of organ system dysfunction and autonomic dysregulation. In particular, the mechanisms or incidences of renal or cardiac complications after TBI are mostly unknown. Autonomic dysfunction following TBI exacerbates secondary injury and may contribute to nonneurologial complications that prolong hospital length of stay. Gaining insights into the mechanisms of autonomic dysfunction can guide advancements in monitoring and treatment paradigms to improve acute survival and long-term prognosis of TBI patients. In this paper, the authors will review the literature on autonomic dysfunction after TBI and possible mechanisms of paroxysmal sympathetic hyperactivity. Specifically, they will discuss the link among the brain, heart, and kidneys and review data to direct future research on and interventions for TBI-induced autonomic dysfunction.

Acute kidney injury after aneurysmal subarachnoid hemorrhage and its effect on patient outcome: an exploratory analysis.

OBJECTIVE: Acute kidney injury (AKI) is associated with death in critically ill patients, but this complication has not been well characterized after aneurysmal subarachnoid hemorrhage (aSAH). The purpose of this study was to determine the incidence of AKI after aSAH and to identify risk factors for renal dysfunction. Secondary objectives were to examine what effect AKI has on patient mortality and functional outcome at 12 weeks post-aSAH. METHODS: The authors performed a post hoc analysis of the Clazosentan to Overcome Neurological Ischemia and Infarction Occurring After Subarachnoid Hemorrhage (CONSCIOUS-1) trial data set (clinical trial registration no.: NCT00111085, https://clinicaltrials.gov). The primary outcome of interest was the development of AKI, which was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. Secondary outcomes of interest were death and a modified Rankin Scale score greater than 2 at 12 weeks post-aSAH. Propensity score matching was used to assess for a significant treatment effect related to clazosentan administration and AKI. Univariate analysis, locally weighted scatterplot smoothing (LOWESS) curves, and stepwise logistic regression models were used to evaluate for associations between baseline or disease-related characteristics and study outcomes. RESULTS: One hundred fifty-six (38%) of the 413 patients enrolled in the CONSCIOUS-1 trial developed AKI during their ICU stay. A history of hypertension (p < 0.001) and the number of nephrotoxic medications administered (p = 0.029) were independent predictors of AKI on multivariate analysis. AKI was an independent predictor of death (p = 0.028) but not a poor functional outcome (p = 0.21) on multivariate testing. Unresolved renal dysfunction was the strongest independent predictor of death in this cohort (p < 0.001). CONCLUSIONS: AKI is a common complication following aSAH. Patients with premorbid hypertension and those treated with nephrotoxic medications may be at greater risk for renal dysfunction. AKI appears to confer an increased probability of death after aSAH.

Value of aggressive surgical and intensive care unit in elderly patients with traumatic spinal cord injury.

OBJECTIVEThe elderly are a growing subpopulation within traumatic spinal cord injury (SCI) patients. Studies have reported high morbidity and mortality rates in elderly patients who undergo surgery for SCI. In this study, the authors compare the perioperative outcomes of surgically managed elderly SCI patients with those of a younger cohort and those reported in the literature.METHODSData on a consecutive series of adult traumatic SCI patients surgically managed at a single institution in the period from 2007 to 2017 were retrospectively reviewed. The cohort was divided into two groups based on age: younger than 70 years and 70 years or older. Assessed outcomes included complications, in-hospital mortality, intensive care unit (ICU) stay, hospital length of stay (LOS), disposition, and neurological status.RESULTSA total of 106 patients were included in the study: 83 young and 23 elderly. The two groups were similar in terms of imaging features (cord hemorrhage and fracture), operative technique, and American Spinal Injury Association Impairment Scale (AIS) grade. The elderly had a significantly higher proportion of cervical SCIs (95.7% vs 71.1%, p = 0.047). There were no significant differences between the young and the elderly in terms of the ICU stay (13.1 vs 13.3 days, respectively, p = 0.948) and hospital LOS (23.3 vs 21.7 days, p = 0.793). Elderly patients experienced significantly higher complication (73.9% vs 43.4%, p = 0.010) and mortality (13.0% vs 1.2%, p = 0.008) rates; in other words, the elderly patients had 1.7 times and 10.8 times the rate of complications and mortality, respectively, than the younger patients. No elderly patients were discharged home (0.0% vs 18.1%, p = 0.029). Discharge AIS grade and AIS grade change were similar between the groups.CONCLUSIONSElderly patients had higher complication and mortality rates than those in younger patients and were less likely to be discharged home. However, it does seem that mortality rates have improved compared to those in prior historical reports.

Association of preoperative hypoalbuminemia with postoperative acute kidney injury in patients undergoing brain tumor surgery: a retrospective study.

OBJECTIVE Hypoalbuminemia is known to be independently associated with postoperative acute kidney injury (AKI). However, little is known about the association between the preoperative serum albumin level and postoperative AKI in patients undergoing brain tumor surgery. The authors investigated the incidence of AKI, impact of preoperative serum albumin level on postoperative AKI, and death in patients undergoing brain tumor surgery. METHODS The authors retrospectively reviewed the electronic medical records and laboratory results of 2363 patients who underwent brain tumor surgery between January 2008 and December 2014. Postoperative AKI was defined according to Kidney Disease: Improving Global Outcomes Definition and Staging (KDIGO). Multivariate logistic regression analysis was used to identify demographic, preoperative laboratory, and intraoperative factors associated with AKI development. Cox proportional hazards models were used to investigate the adjusted odds ratio and hazard ratio for the association between preoperative serum albumin level and outcome variables. RESULTS The incidence of AKI was 1.8% (n = 43) using KDIGO criteria. The incidence of AKI was higher in patients with a preoperative serum albumin level < 3.8 g/dl (3.5%) than in those with a preoperative serum albumin level ≥ 3.8 g/dl (1.2%, p < 0.001). The overall mortality was also higher in the former than in the latter group (5.0% vs 1.8%, p < 0.001). After inverse probability of treatment-weighting adjustment, a preoperative serum albumin level < 3.8 g/dl was also found to be associated with postoperative AKI (OR 1.981, 95% CI 1.022-3.841; p = 0.043) and death (HR 2.726, 95% CI 1.522-4.880; p = 0.001). CONCLUSIONS The authors' results demonstrated that a preoperative serum albumin level of < 3.8 g/dl was independently associated with AKI and mortality in patients undergoing brain tumor surgery.

Increased risk of acute kidney injury associated with higher infusion rate of mannitol in patients with intracranial hemorrhage.

OBJECT: Mannitol, an osmotic agent used to decrease intracranial pressure, can cause acute kidney injury (AKI). The objectives of this study were to assess the impact of mannitol on the incidence and severity of AKI and to identify risk factors and outcome for AKI in patients with intracranial hemorrhage (ICH). METHODS: The authors retrospectively evaluated 153 adult patients who received mannitol infusion after ICH between January 2005 and December 2009 in the neurosurgical intensive care unit. Multivariate analysis was used to evaluate the risk factors for AKI after ICH. Based on the odds ratio, weighted scores were assigned to predictors of AKI. RESULTS: The overall incidence of AKI among study participants was 10.5% (n = 16). Acute kidney injury occurred more frequently in patients who received mannitol infusion at a rate ≥ 1.34 g/kg/day than it did in patients who received mannitol infusion at a rate < 1.34 g/kg/day. A higher mannitol infusion rate was associated with more severe AKI. Independent risk factors for AKI were mannitol infusion rate ≥ 1.34 g/kg/day, age ≥ 70 years, diastolic blood pressure (DBP) ≥ 110 mm Hg, and glomerular filtration rate < 60 ml/min/1.73 m(2). The authors developed a risk model for AKI, wherein patients with a higher risk score showed a graded association with a higher incidence of AKI. CONCLUSIONS: The incidence of AKI following mannitol infusion in patients with ICH was 10.5%. A higher mannitol infusion rate was associated with more frequent and more severe AKI. Additionally, age ≥ 70 years, DBP ≥ 110 mm Hg, and established renal dysfunction before starting mannitol therapy were associated with development of AKI.