Associations between cerebrospinal fluid protein concentrations, serum albumin concentrations and intracranial pressure in neurotrauma and intracranial haemorrhage

The Association Between Neurological Prognosis and the Degree of Blood-Brain Barrier Disruption in Cardiac Arrest Survivors Who Underwent Target Temperature Management

BACKGROUND

This study aimed to compare day-specific associations of blood-brain barrier (BBB) disruption with neurological outcome in survivors of out-of-hospital cardiac arrest (OHCA) treated with target temperature management (TTM) and lumbar drainage.

METHODS

This retrospective single-center study included 68 survivors of OHCA who underwent TTM between April 2018 and December 2019. The albumin quotient (Q_A) was calculated as Q_A = albumin_{cerebrospinal fluid}/albumin_serum immediately (day 1) and 24 (day 2), 48 (day 3), and 72 h (day 4) after the return of spontaneous circulation. The degree of BBB disruption was weighted using the following scoring system: Q_A value of 0.007 or less (normal), Q_A value greater than 0.007-0.01 (mild), Q_A value greater than 0.01-0.02 (moderate), and Q_A value greater than 0.02 (severe). Points were assigned as follows: 0 (normal), 1 (mild), 4 (moderate), and 9 (severe). Neurological outcome was determined at 6 months after the return of spontaneous circulation, as well as cerebral performance category (CPC), dichotomized as good (CPC score 1-2) and poor (CPC score 3-5) outcome.

RESULTS

We enrolled 68 patients (48 men, 71%); 37 (54%) patients had a poor neurological outcome. The distributions of poor versus good outcomes at 6 months in patients with moderate and severe BBB disruption were 19 of 22 (80%) vs. 18 of 46 (50%) on day 1, 31 of 37 (79%) vs. 6 of 31 (32%) on day 2, 32 of 37 (81%) vs. 5 of 31 (30%) on day 3, and 32 of 39 (85%) vs. 5 of 29 (30%) on day 4 (P < 0.001), respectively. Using receiver operating characteristic analyses, optimal cutoff values (sensitivity, specificity) of Q_A levels for the prediction of neurological outcome were as follows: day 1, greater than 0.009 (56.8%, 87.1%); day 2, greater than 0.012 (81.1%, 87.1%); day 3, greater than 0.013 (83.8%, 87.1%); day 4, greater than 0.013 (86.5%, 87.1%); the sum of all time points, greater than 0.039 (89.5%, 79.4%); and scoring system, greater than 9 (91.9%, 87.1%).

CONCLUSIONS

In this proof of concept study, Q_A was associated with poor neurological outcome in survivors of OHCA treated with TTM with no contraindication to lumbar drainage. A large multicenter prospective study is needed to validate the utility of BBB disruption as a prognosticator of neurological outcome.

Impact of the serum albumin level on acute kidney injury after cerebral artery aneurysm clipping

Background

Although hypoalbuminemia is a known risk factor for acute kidney injury (AKI) following surgery, little is known about its effects following aneurysm clipping surgery. We aimed to investigate the predictors of AKI and overall mortality and assessed the relationship between preoperative albumin and postoperative outcomes after aneurysm clipping surgery.

Methods

This study included 2,339 patients who underwent aneurysm clipping surgery. According to the criteria updated by the Kidney Disease: Improving Global Outcomes (KDIGO), patients were classified into AKI and no AKI group. Independent AKI predictors were analyzed by multivariate methods, and the influence of AKI on the outcome variables was assessed with by propensity score matching analysis. Survival in relation to AKI was analyzed using the Kaplan–Meier method.

Results

The total proportion of patients who developed AKI was 1.9%. The cutoff value of preoperative albumin for predicting AKI was 3.9 g/dL. Multivariate analyses showed that preoperative albumin≤ 3.9 g/dL, aneurysmal subarachnoid hemorrhage, male sex, phenylephrine use, and hemoglobin were associated with postoperative AKI development. In multivariate analysis, mortality was increased in AKI patients (p< 0.01). After propensity score matching, preoperative albumin≤ 3.9 g/dL was significantly related to AKI and overall mortality.

Conclusion

Preoperative albumin≤ 3.9 g/dL is associated with postoperative AKI and mortality.

Differential disruption of blood-brain barrier in severe traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a significant cause of death and disability in young adults, but not much is known about the incidence and characteristics of blood-brain barrier (BBB) dysfunction in this group. In this proof of concept study, we sought to quantify the incidence of BBB dysfunction (defined as a cerebrospinal fluid (CSF)-plasma albumin quotient of ≥0.007) and examine the relationship between plasma and CSF levels of proteins and electrolytes, in patients with severe TBI.

METHODS

We recruited 30 patients, all of whom were receiving hypertonic 20 % saline infusion for intracranial hypertension and had external ventricular drains in situ. Simultaneous CSF and blood samples were obtained. Biochemical testing was performed for sodium, osmolality, potassium, glucose, albumin, immunoglobulin-G, and total protein.

RESULTS

Eleven patients (37 %) showed evidence of impairment of passive BBB function, with a CSF-plasma albumin quotient of ≥0.007. There were strong positive correlations seen among CSF-plasma albumin quotient and CSF-plasma immunoglobulin-G quotient and CSF-plasma total protein quotient (r = 0.967, P < 0.001 and r = 0.995, P < 0.001, respectively). We also found a higher maximum intracranial pressure (24 vs. 21 mmHg, P = 0.029) and a trend toward increased mortality (27 vs. 11 %, P = 0.33) in patients with BBB disruption.

CONCLUSIONS

In summary, passive BBB dysfunction is common in patients with severe TBI, and may have important implications for effectiveness of osmotherapy and long-term outcomes. Also, our results suggest that the CSF-plasma total protein quotient, a measurement which is readily available, can be used instead of the CSF-plasma albumin quotient for evaluating BBB dysfunction.

Prognostic significance of blood-brain barrier disruption in patients with severe nonpenetrating traumatic brain injury requiring decompressive craniectomy

OBJECT

The authors assessed the risk factors and outcomes associated with blood-brain barrier (BBB) disruption in patients with severe, nonpenetrating, traumatic brain injury (TBI) requiring decompressive craniectomy.

METHODS

At 2 major neurotrauma centers in Western Australia, a retrospective cohort study was conducted among 97 adult neurotrauma patients who required an external ventricular drain (EVD) and decompressive craniectomy during 2004-2012. Glasgow Outcome Scale scores were used to assess neurological outcomes. Logistic regression was used to identify factors associated with BBB disruption, defined by a ratio of total CSF protein concentrations to total plasma protein concentration > 0.007 in the earliest CSF specimen collected after TBI.

RESULTS

Of the 252 patients who required decompressive craniectomy, 97 (39%) required an EVD to control intracranial pressure, and biochemical evidence of BBB disruption was observed in 43 (44%). Presence of disruption was associated with more severe TBI (median predicted risk for unfavorable outcome 75% vs 63%, respectively; p = 0.001) and with worse outcomes at 6, 12, and 18 months than was absence of BBB disruption (72% vs 37% unfavorable outcomes, respectively; p = 0.015). The only risk factor significantly associated with increased risk for BBB disruption was presence of nonevacuated intracerebral hematoma (> 1 cm diameter) (OR 3.03, 95% CI 1.23-7.50; p = 0.016). Although BBB disruption was associated with more severe TBI and worse long-term outcomes, when combined with the prognostic information contained in the Corticosteroid Randomization after Significant Head Injury (CRASH) prognostic model, it did not seem to add significant prognostic value (area under the receiver operating characteristic curve 0.855 vs 0.864, respectively; p = 0.453).

CONCLUSIONS

Biochemical evidence of BBB disruption after severe nonpenetrating TBI was common, especially among patients with large intracerebral hematomas. Disruption of the BBB was associated with more severe TBI and worse long-term outcomes, but when combined with the prognostic information contained in the CRASH prognostic model, this information did not add significant prognostic value.

Albumin resuscitation for traumatic brain injury: is intracranial hypertension the cause of increased mortality?

Mortality is higher in patients with traumatic brain injury (TBI) resuscitated with albumin compared with saline, but the mechanism for increased mortality is unknown. In patients from the Saline vs. Albumin Fluid Evaluation (SAFE) study with TBI who underwent intracranial pressure (ICP) monitoring, interventional data were collected from randomization to day 14 to determine changes in ICP (primary outcome) and in therapies used to treat increased ICP. Pattern mixture modelling, designed to address informative dropouts, was used to compare temporal changes between the albumin and saline groups, and 321 patients were identified, of whom 164 (51.1%) received albumin and 157 (48.9%) received saline. There was a significant linear increase in mean ICP and significantly more deaths in the albumin group compared with saline when ICP monitoring was discontinued during the first week (1.30±0.33 vs. -0.37±0.36, p=0.0006; and 34.4% vs. 17.4%; p=0.006 respectively), but not when monitoring ceased during the second week (-0.08±0.44 vs. -0.23±0.38, p=0.79; and 18.6% vs. 12.1%; p=0.36 respectively). There were statistically significant differences in the mean total daily doses of morphine (-0.42±0.07 vs. -0.66±0.0, p=0.0009), propofol (-0.45±0.11 vs. -0.76±0.11; p=0.034) and norepinephrine (-0.50±0.07 vs. -0.74±0.07) and in temperature (0.03±0.03 vs. 0.16±0.03; p=0.0014) between the albumin and saline groups when ICP monitoring ceased during the first week. The use of albumin for resuscitation in patients with severe TBI is associated with increased ICP during the first week. This is the most likely mechanism of increased mortality in these patients.