Arterial lactate in traumatic brain injury - Relation to intracranial pressure dynamics, cerebral energy metabolism and clinical outcome

Cerebrospinal Fluid Lactate Levels as a Prognostic Indicator in Patients With Cryptococcal Meningitis Who Are HIV Negative: A Retrospective Cohort Study

Background

Cryptococcal meningitis (CM) is a severe central nervous system infection. In patients with HIV infections and coexisting CM, elevated baseline cerebrospinal fluid (CSF) lactate levels can predict increased mortality. However, the CSF lactate level's significance in patients with CM who are HIV negative remains unclear, necessitating further investigation to elucidate the potential distinctions and enhance patient management. This study investigated the significance of CSF lactate levels in patients with CM who were HIV negative.

Methods

This retrospective study utilized data from the clinical databases of patients who underwent lumbar punctures at a medical center in Kaohsiung City, southern Taiwan. Demographic data, CSF lactate levels, routine CSF analyses, and hematologic and neurologic findings were evaluated. The optimal CSF lactate threshold value was determined by the Youden index.

Results

This retrospective study included 70 patients with CM, among whom 44 (63%) and 26 (37%) tested negative and positive for HIV, respectively. The group without HIV exhibited higher CSF lactate levels, with an optimal CSF lactate cutoff point of 7.935 mmol/L for predicting 90-day mortality, resulting in significant predictive accuracies (area under the curve, 0.755; sensitivity, 57.1%; specificity, 100%); this value was an independent mortality predictor in patients who were HIV negative. In patients with CM who were HIV negative, CSF lactate levels ≥7.935 mmol/L correlated with higher mortality rates but without statistical significance. All patients with CM who were HIV negative and had CSF lactate levels ≥7.935 mmol/L died within 3 months of admission.

Conclusions

Patients with CM who were HIV negative had elevated CSF lactate levels that correlated with adverse outcomes, enabling early identification of high-risk individuals.

Prehospital Lactate Levels Obtained in the Ambulance and Prediction of 2-Day In-Hospital Mortality in Patients With Traumatic Brain Injury

BACKGROUND AND OBJECTIVES

To analyze the ability of prehospital lactate levels to predict 2-day in-hospital mortality in patients with traumatic brain injury (TBI), severe TBI (Glasgow Coma Scale (GCS) ≤ 8 points), and mild or moderate TBI (GCS ≥ 9 points). Second, 90-day mortality was also explored.

METHODS

This was a prospective, multicenter, emergency medical services (EMSs) delivery, ambulance-based, derivation-validation cohort study developed in 5 tertiary hospitals (Spain), from November 1, 2019, to July 31, 2022. Patients were recruited from among all phone requests for emergency assistance among adults who were later evacuated to referral hospitals with acute TBI. The exclusion criteria were minors, pregnancy, trauma patients without TBI, delayed presentations, patients were discharged in situ, participants with cardiac arrest, and unavailability to obtain a blood sample. The primary outcome was all-cause 2-day in-hospital mortality and 90-day mortality in patients with moderate or mild TBI compared with patients with severe TBI. Clinical and analytical parameters (lactate and glucose) were collected. The discriminative power (area under the receiver operating characteristic curve [AUC]) and calibration curve were calculated for 2 geographically separated cohorts.

RESULTS

A total of 509 patients were ultimately included. The median age was 58 years (interquartile range: 43-75), and 167 patients were female (32.8%). The primary outcome occurred in 9 (2.2%) of 415 patients with moderate or mild TBI and in 42 (44.7%) of 94 patients with severe TBI. The predictive capacity of the lactate concentration was globally validated in our cohort, for which the AUC was 0.874 (95% CI 0.805-0.942) for the validation cohort. The ability of the GCS score to predict lactate concentration was greater in patients with a GCS score ≥9 points, with an AUC of 0.925 (95% CI 0.808-1.000) and a negative predictive value of 99.09 (95% CI 98.55-99.64) in the validation cohort.

CONCLUSION

Our results show the benefit of using lactate in all patients with TBI, particularly in those with a GCS ≥9 points. Routine incorporation of lactate in the screening of patients with TBI could presumably reduce mortality and deterioration rates because of quicker and better identification of patients at risk.

Thiamine use is associated with better outcomes for traumatic brain injury patients

Background

Traumatic brain injury (TBI) is a global health concern that often leads to poor prognosis. We designed this study to explore whether thiamine use is associated with a better prognosis of TBI.

Methods

TBI patients selected from the Medical Information Mart for Intensive Care-III database were included in the study. Univariate and multivariate Cox regression analyses were performed to examine the relationship between thiamine use and mortality in TBI patients. Propensity score matching (PSM) was utilized to generate balanced cohorts of the non-thiamine use group and the thiamine use group. Subgroup analysis was performed in the cohort after PSM to verify the association between thiamine use and mortality in TBI patients across different stratifications.

Results

The incidence of thiamine use in TBI was 18.3%. The thiamine use group had a lower 30-day mortality rate (p < 0.001), a longer length of ICU stay (p < 0.001), and a longer length of hospital stay (p < 0.001) than the non-thiamine use group, both in the primary cohort before PSM and the cohort after PSM. A multivariate Cox regression analysis confirmed that thiamine use was independently associated with mortality (OR = 0.454, p < 0.001) after adjusting for confounding effects. In the cohort after PSM, the subgroup analysis showed that thiamine use is associated with lower mortality in TBI patients with a Glasgow Coma Scale (GCS) score of < 13, but it is not associated with mortality in TBI patients whose GCS score is ≥13.

Conclusion

Thiamine supplementation is effective in improving the outcome of TBI, except in cases of mild TBI. The optimal thiamine supplementation strategy for TBI is worthwhile to be explored in future studies.

The significance of admission blood lactate and fibrinogen in pediatric traumatic brain injury: a single-center clinical study

BACKGROUND

Traumatic brain injury (TBI) is a significant cause of morbidity and mortality in pediatric patients, leading to long-term physical, cognitive, and psychological impairments. Blood lactate and fibrinogen levels have emerged as potential biomarkers associated with tissue hypoperfusion and coagulation dysfunction, respectively. However, limited research has specifically focused on the significance of these biomarkers in pediatric TBI. This study aimed to investigate the clinical significance of blood lactate and fibrinogen levels upon admission in pediatric patients with traumatic brain injury.

METHODS

The medical records of 80 children with a traumatic brain injury who were admitted from January 2017 to January 2021 were retrospectively analyzed. The two groups were compared according to whether the blood lactate in the admission arterial blood gas increased and the fibrinogen content in the coagulation function decreased. The clinical data of the children in the two groups were different, and then they were divided into a good prognosis group and a poor prognosis group according to the GOS prognostic score, and the differences in the clinical indicators of the two groups were compared.

RESULTS

Among the 80 patients, 33 had elevated blood lactate levels, 34 had decreased fibrinogen levels, and 29 had an unfavorable outcome (GOS < 4). Compared to the normal blood lactate group, there were no statistically significant differences in age, sex ratio, or platelet count in the elevated blood lactate group (P > 0.05). However, the elevated blood lactate group had lower Glasgow Coma Scale (GCS) scores upon admission, higher blood lactate levels, lower fibrinogen levels, longer hospital stay, lower GOS scores, and a higher proportion of GOS < 4 (P < 0.05). Compared to the normal fibrinogen group, there were no statistically significant differences in age, sex ratio, or platelet count in the decreased fibrinogen group (P > 0.05). However, the decreased fibrinogen group had lower GCS scores upon admission, higher blood lactate levels, lower fibrinogen levels, longer hospital stays, lower GOS scores, and a higher proportion of GOS < 4 (P < 0.05). Compared to the favorable outcome group, there were no statistically significant differences in age, sex ratio, or platelet count in the unfavorable outcome group (P > 0.05). However, the unfavorable outcome group had lower GCS scores upon admission, higher blood lactate levels, lower fibrinogen levels, longer hospital stays, a higher incidence of pulmonary infection, a higher incidence of stress ulcers, and lower GOS scores (P < 0.05).

CONCLUSION

The levels of blood lactate and fibrinogen may represent the severity of children with traumatic brain injury and may be risk factors for poor prognosis of children with traumatic brain injury.

Association of initial lactate levels and red blood cell transfusion strategy with outcomes after severe trauma: a post hoc analysis of the RESTRIC trial

BACKGROUND

The appropriateness of a restrictive transfusion strategy for those with active bleeding after traumatic injury remains uncertain. Given the association between tissue hypoxia and lactate levels, we hypothesized that the optimal transfusion strategy may differ based on lactate levels. This post hoc analysis of the RESTRIC trial sought to investigate the association between transfusion strategies and patient outcomes based on initial lactate levels.

METHODS

We performed a post hoc analysis of the RESTRIC trial, a cluster-randomized, crossover, non-inferiority multicenter trials, comparing a restrictive and liberal red blood cell transfusion strategy for adult trauma patients at risk of major bleeding. This was conducted during the initial phase of trauma resuscitation; from emergency department arrival up to 7 days after hospital admission or intensive care unit (ICU) discharge. Patients were grouped by lactate levels at emergency department arrival: low (< 2.5 mmol/L), middle (≥ 2.5 and < 4.0 mmol/L), and high (≥ 4.0 mmol/L). We compared 28 days mortality and ICU-free and ventilator-free days using multiple linear regression among groups.

RESULTS

Of the 422 RESTRIC trial participants, 396 were analyzed, with low (n = 131), middle (n = 113), and high (n = 152) lactate. Across all lactate groups, 28 days mortality was similar between strategies. However, in the low lactate group, the restrictive approach correlated with more ICU-free (β coefficient 3.16; 95% CI 0.45 to 5.86) and ventilator-free days (β coefficient 2.72; 95% CI 0.18 to 5.26) compared to the liberal strategy. These findings persisted even after excluding patients with severe traumatic brain injury.

CONCLUSIONS

Our results suggest that restrictive transfusion strategy might not have a significant impact on 28-day survival rates, regardless of lactate levels. However, the liberal transfusion strategy may lead to shorter ICU- and ventilator-free days for patients with low initial blood lactate levels.

Cerebral Autoregulation-guided Management of Adult and Pediatric Traumatic Brain Injury

Cerebral autoregulation (CA) plays a vital role in maintaining cerebral blood flow in response to changes in systemic blood pressure. Impairment of CA following traumatic brain injury (TBI) may exacerbate the injury, potentially impacting patient outcomes. This focused review addresses 4 key questions regarding the measurement, natural history of CA after TBI, and potential clinical implications of CA status and CA-guided management in adults and children with TBI. We examine the feasibility and safety of CA assessment, its association with clinical outcomes, and the potential for reversing deranged CA following TBI. Finally, we discuss how the knowledge of CA status may affect TBI management and outcomes.

Temperature Changes in Poor-Grade Aneurysmal Subarachnoid Hemorrhage: Relation to Injury Pattern, Intracranial Pressure Dynamics, Cerebral Energy Metabolism, and Clinical Outcome

BACKGROUND

The aim was to study the course of body temperature in the acute phase of poor-grade aneurysmal subarachnoid hemorrhage (aSAH) in relation to the primary brain injury, cerebral physiology, and clinical outcome.

METHODS

In this observational study, 166 patients with aSAH treated at the neurosurgery department at Uppsala University Hospital in Sweden between 2008 and2018 with temperature, intracranial pressure (ICP), and microdialysis (MD) monitoring were included. The first 10 days were divided into the early phase (days 1-3) and the vasospasm phase (days 4-10).

RESULTS

Normothermia (temperature = 36-38 °C) was most prevalent in the early phase. A lower mean temperature at this stage was univariately associated with a worse primary brain injury, with higher Fisher grade and higher MD glycerol concentration, as well as a worse neurological recovery at 1 year. There was otherwise no association between temperature and cerebral physiological variables in the early phase. There was a transition toward an increased burden of hyperthermia (temperature > 38 °C) in the vasospasm phase. This was associated with concurrent infections but not with neurological or radiological injury severity at admission. Elevated temperature was associated with higher MD pyruvate concentration, lower rate of an MD pattern indicative of ischemia, and higher rate of poor neurological recovery at 1 year. There was otherwise no association between temperature and cerebral physiological variables in the vasospasm phase. The associations between temperature and clinical outcome did not hold true in multiple logistic regression analyses.

CONCLUSIONS

Spontaneously low temperature in the early phase reflected a worse primary brain injury and indicated a worse outcome prognosis. Hyperthermia was common in the vasospasm phase and was more related to infections than primary injury severity but also with a more favorable energy metabolic pattern with better substrate supply, possibly related to hyperemia.

Fine tuning of neurointensive care in aneurysmal subarachnoid hemorrhage: From one-size-fits-all towards individualized care

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe type of acute brain injury with high mortality and burden of neurological sequelae. General management aims at early aneurysm occlusion to prevent re-bleeding, cerebrospinal fluid drainage in case of increased intracranial pressure and/or acute hydrocephalus, and cerebral blood flow augmentation in case of delayed ischemic neurological deficits. In addition, the brain is vulnerable to physiological insults in the acute phase and neurointensive care (NIC) is important to optimize the cerebral physiology to avoid secondary brain injury. NIC has led to significantly better neurological recovery following aSAH, but there is still great room for further improvements. First, current aSAH NIC management protocols are to some extent extrapolated from those in traumatic brain injury, notwithstanding important disease-specific differences. Second, the same NIC management protocols are applied to all aSAH patients, despite great patient heterogeneity. Third, the main variables of interest, intracranial pressure and cerebral perfusion pressure, may be too superficial to fully detect and treat several important pathomechanisms. Fourth, there is a lack of understanding not only regarding physiological, but also cellular and molecular pathomechanisms and there is a need to better monitor and treat these processes. This narrative review aims to discuss current state-of-the-art NIC of aSAH, knowledge gaps in the field, and future directions towards a more individualized care in the future.

The Role of the Glucose Potassium Ratio in the Management of Traumatic Brain Injury

Objective

Traumatic brain injury (TBI) has become a worldwide public health issue, raising concerns about which tool might be useful to guide initial management at hospital admission, especially to decide whether the patient would benefit from an opportune surgical intervention. Recently, the glucose-to-potassium ratio has more accurate predictive values than other biomarkers and is useful for its simplicity to obtain. To correlate each biomarker with the outcome for every patient with TBI.

Methods

The analysis included patients treated in a single institution between 2020 and 2021, diagnosed with mild TBI that required neurosurgery, moderate or severe TBI. Blood samples were obtained at admission, and the glucose-to-potassium ratio was calculated retrospectively. Then, these values and other variables were compared with the outcome at 6 and 12 months. Extracranial lesions that directly contributed to the outcome, a Glasgow Coma Scale of 3 and below, hemodynamic instability, and cardiac arrest were exclusion criteria.

Results

Forty-seven patients who reached the criteria were examined, 35 (74%) had a favorable outcome and 12 (26%) a poor one. The only biomarker significantly related to the outcome was the glucose-to-potassium ratio in both the bivariate and multivariate analysis (p=0.04; odds ratio, 8.61; 95% confidence interval, 1.07-69.6).

Conclusion

An increase in the glucose-to-potassium ratio was the only biomarker associated with poor outcomes and increased mortality.

Frequency of blood lactate elevation following esophagectomy and its association to postoperative complications

BACKGROUND

Esophagectomy is a major surgical intervention and a cornerstone in the treatment of esophageal cancer. There is clinical experience that blood lactate concentration often is elevated in the period following esophagectomy, but the incidence and clinical consequences are sparsely studied.

METHODS

We extracted data from all patients undergoing esophagectomy at Karolinska University Hospital 2016-2018, n = 153. Most were performed with minimally invasive technique, n = 130. Blood lactate values directly after surgery, highest value during the first night, and morning level on postoperative day one were recorded. Primary outcome was hospital length of stay and secondary outcome was a composite of postoperative infection, additional surgery, or intensive care during the hospital stay. Development of anastomotic leak was analyzed separately.

RESULTS

Postoperative hyperlactatemia was common as 93% of patients had peak lactate concentration >1.6 mmol/L and 27% >3.5 mmol/L in the first night following operation. Median hospital length of stay was 14 days. Blood lactate showed a weak correlation to hospital stay and intensive care the morning following surgery, but not at arrival to postoperative ward. There were no statistical differences between those with and without anastomotic leak at any of the time points. Elevated lactate in the first 12-16 h postoperatively was related to surgical factors (open technique, surgery time, and perioperative bleeding) but not to patient related factors (ASA-class, Charlson comorbidity index, sex, age) or cumulative fluid balance.

CONCLUSION

In conclusion, elevated blood lactate in the immediate time following esophagectomy showed a weak association to intensive care and length of stay but not anastomotic leak.

Microdialysis-Based Classifications of Abnormal Metabolic States after Traumatic Brain Injury: A Systematic Review of the Literature

After traumatic brain injury (TBI), cerebral metabolism can become deranged, contributing to secondary injury. Cerebral microdialysis (CMD) allows cerebral metabolism assessment and is often used with other neuro-monitoring modalities. CMD-derived parameters such as the lactate/pyruvate ratio (LPR) show a failure of oxidative energy generation. CMD-based abnormal metabolic states can be described following TBI, informing the etiology of physiological derangements. This systematic review summarizes the published literature on microdialysis-based abnormal metabolic classifications following TBI. Original research studies in which the populations were patients with TBI were included. Studies that described CMD-based classifications of metabolic abnormalities were included in the synthesis of the narrative results. A total of 825 studies underwent two-step screening after duplicates were removed. Fifty-three articles that used CMD in TBI patients were included. Of these, 14 described abnormal metabolic states based on CMD parameters. Classifications were heterogeneous between studies. LPR was the most frequently used parameter in the classifications; high LPR values were described as metabolic crisis. Ischemia was consistently defined as high LPR with low CMD substrate levels (glucose or pyruvate). Mitochondrial dysfunction, describing inability to use energy substrate despite availability, was identified based on raised LPR with near-normal levels of pyruvate. This is the first systematic review summarizing the published literature on microdialysis-based abnormal metabolic states following TBI. Although variability exists among individual classifications, there is broad agreement about broad definitions of metabolic crisis, ischemia, and mitochondrial dysfunction. Identifying the etiology of deranged cerebral metabolism after TBI is important for targeting therapeutic interventions.

Cerebral multimodality monitoring in adult neurocritical care patients with acute brain injury: A narrative review

Cerebral multimodality monitoring (MMM) is, even with a general lack of Class I evidence, increasingly recognized as a tool to support clinical decision-making in the neuroscience intensive care unit (NICU). However, literature and guidelines have focused on unimodal signals in a specific form of acute brain injury. Integrating unimodal signals in multiple signal monitoring is the next step for clinical studies and patient care. As such, we aimed to investigate the recent application of MMM in studies of adult patients with traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), intracerebral hemorrhage (ICH), acute ischemic stroke (AIS), and hypoxic ischemic brain injury following cardiac arrest (HIBI). We identified continuous or daily updated monitoring modalities and summarized the monitoring setting, study setting, and clinical characteristics. In addition, we discussed clinical outcome in intervention studies. We identified 112 MMM studies, including 11 modalities, over the last 7 years (2015-2022). Fifty-eight studies (52%) applied only two modalities. Most frequently combined were ICP monitoring (92 studies (82%)) together with PbtO₂ (63 studies (56%). Most studies included patients with TBI (59 studies) or SAH (53 studies). The enrollment period of 34 studies (30%) took more than 5 years, whereas the median sample size was only 36 patients (q1- q3, 20-74). We classified studies as either observational (68 studies) or interventional (44 studies). The interventions were subclassified as systemic (24 studies), cerebral (10 studies), and interventions guided by MMM (11 studies). We identified 20 different systemic or cerebral interventions. Nine (9/11, 82%) of the MMM-guided studies included clinical outcome as an endpoint. In 78% (7/9) of these MMM-guided intervention studies, a significant improvement in outcome was demonstrated in favor of interventions guided by MMM. Clinical outcome may be improved with interventions guided by MMM. This strengthens the belief in this application, but further interdisciplinary collaborations are needed to overcome the heterogeneity, as illustrated in the present review. Future research should focus on increasing sample sizes, improved data collection, refining definitions of secondary injuries, and standardized interventions. Only then can we proceed with complex outcome studies with MMM-guided treatment.

The combination of arterial lactate level with GCS-pupils score to evaluate short term prognosis in traumatic brain injury: a retrospective study

Background

The aim of the study was to determine whether the combination of Glasgow Coma Scale (GCS) and Pupil responses score (GCSP) with arterial lactate level would be an index to predict the short term prognosis in patients with traumatic brain injury (TBI).

Methods

A retrospective study was performed enrolling all TBI patients admitted to intensive care unit (ICU) from 2019 to 2020. The demographics, clinical characteristics, and arterial lactate concentration were recorded. The GCSP and arterial blood analysis (ABG) with lactate was tested as soon as the patient was admitted to ICU. The Glasgow Outcome Scale (GOS) after discharge was regarded as the clinical outcome. A new index named GCSP-L was the combination of GCSP and lactate concentration. GCSP-L was the GCSP score (range 1-15) plus the lactate score (range 0-2). The lactate score was defined based on different lactate concentrations. If lactate was below 2 mmol/L, lactate score was 0, which above 5 mmol/L was 2 and between 2 and 5 mmol/L, the score was 1. As the range of GCSP was 1-15, the range of the GCSP-L was 1 to 17. The area under receiver operating characteristic curve (AUC) was calculated to evaluate the predictive ability of GCSP, lactate and GCSP-L. Statistical significance was set when p value < 0.05.

Results

A total of 192 TBI patients were included in the study. Based on GCSP, mild, moderate, and severe TBI were 13.02, 14.06 and 72.92%, respectively. There were 103 (53.65%) patients with the lactate concentration below 2 mmol/L (1.23 ± 0.37 mmol/l), 63 (32.81%) of the range from 2 to 5 (3.04 ± 2.43 mmol/l) and 26 (13.54%) were above 5 mmol/l (7.70 ± 2.43 mmol/l). The AUC was 0.866 (95% CI 0.827-0.904) for GCSP-L, 0.812 (95% CI 0.765-0.858) for GCSP and 0.629 (95% CI 0.570—0.0.688) for lactate. The AUC of GCSP-L was higher than the other two, GCSP and lactate alone.

Conclusions

The combination of GCSP and lactate concentration can be used to predict the short term prognosis in TBI patients.

Association of Arterial Metabolic Content with Cerebral Blood Flow Regulation and Cerebral Energy Metabolism-A Multimodality Analysis in Aneurysmal Subarachnoid Hemorrhage

Background

In this study, the association of the arterial content of oxygen, carbon dioxide, glucose, and lactate with cerebral pressure reactivity, energy metabolism and clinical outcome after aneurysmal subarachnoid hemorrhage (aSAH) was investigated.

Methods

In this retrospective study, 60 patients with aSAH, treated at the neurointensive care (NIC), Uppsala University Hospital, Sweden, between 2016 and 2021 with arterial blood gas (ABG), intracranial pressure, and cerebral microdialysis (MD) monitoring were included. The first 10 days were divided into an early phase (day 1 to 3) and a vasospasm phase (day 4 to 10).

Results

Higher arterial lactate was independently associated with higher/worse pressure reactivity index (PRx) in the early phase (β = 0.32, P = .02), whereas higher pO₂ had the opposite association in the vasospasm phase (β = −0.30, P = .04). Arterial glucose and pCO₂ were not associated with PRx. Higher arterial lactate (β = 0.29, P = .05) was independently associated with higher MD-glucose in the vasospasm phase, whereas higher pO₂ had the opposite association in the vasospasm phase (β = −0.33, P = .03). Arterial glucose and pCO₂ were not associated with MD-glucose. Higher pCO₂ in the early phase, lower arterial glucose in both phases, and lower arterial lactate in the vasospasm phase were associated (P < .05) with better clinical outcome.

Conclusions

Arterial variables associated with more vasoconstriction (higher pO₂ and lower arterial lactate) were associated with better cerebral pressure reactivity, but worse energy metabolism. In severe aSAH, when cerebral large-vessel vasospasm with exhausted distal vasodilation is common, more vasoconstriction could increase distal vasodilatory reserve and pressure reactivity, but also reduce cerebral blood flow and metabolic supply. The MD may be useful to monitor the net effects on cerebral metabolism in PRx-targeted NIC.

Serum Lactate Level in Early Stage Is Associated With Acute Kidney Injury in Traumatic Brain Injury Patients

Background

Acute kidney injury (AKI) is a common complication in the clinical practice of managing patients with traumatic brain injury (TBI). Avoiding the development of AKI is beneficial for the prognosis of patients with TBI. We designed this study to testify whether serum lactate could be used as a predictive marker of AKI in patients with TBI.

Materials and Methods

In total, 243 patients with TBI admitted to our hospital were included in this study. Univariate and multivariate logistic regression analyses were utilized to analyze the association between lactate and AKI. The receiver operating characteristic (ROC) curves were drawn to verify the predictive value of lactate and the logistic model.

Results

Acute kidney injury group had higher age (p = 0.016), serum creatinine (p < 0.001), lactate (p < 0.001), and lower Glasgow Coma Scale (GCS; p = 0.021) than non-AKI group. Multivariate logistic regression showed that age [odds ratio (OR) = 1.026, p = 0.022], serum creatinine (OR = 1.020, p = 0.010), lactate (OR = 1.227, p = 0.031), fresh frozen plasma (FFP) transfusion (OR = 2.421, p = 0.045), and platelet transfusion (OR = 5.502, p = 0.044) were risk factors of AKI in patients with TBI. The area under the ROC curve (AUC) values of single lactate and predictive model were 0.740 and 0.807, respectively.

Conclusion

Serum lactate level in the early phase is associated with AKI in patients with TBI. Lactate is valuable for clinicians to evaluate the probability of AKI in patients with TBI.

Cerebral Pressure Autoregulation in Brain Injury and Disorders-A Review on Monitoring, Management, and Future Directions

The role of cerebral pressure autoregulation (CPA) in brain injury and disorders has gained increased interest. The CPA is often disturbed as a consequence of acute brain injury, which contributes to further brain damage and worse outcome. Specifically, in severe traumatic brain injury, CPA disturbances predict worse clinical outcome and targeting an autoregulatory-oriented optimal cerebral perfusion pressure threshold may improve brain energy metabolism and clinical outcome. In aneurysmal subarachnoid hemorrhage, cerebral vasospasm in combination with distal autoregulatory disturbances precipitate delayed cerebral ischemia. The role of optimal cerebral perfusion pressure targets is less clear in aneurysmal subarachnoid hemorrhage, but high cerebral perfusion pressure targets are generally favorable in the vasospasm phase. In acute ischemia, autoregulatory disturbances may occur and autoregulatory-oriented blood pressure (optimal mean arterial pressure) management reduces the risk of hemorrhagic transformation, brain edema, and unfavorable outcome. In chronic occlusive disease such as moyamoya, the gradual reduction of the cerebral circulation leads to compensatory distal vasodilation and the residual CPA capacity predicts the risk for cerebral ischemia. In spontaneous intracerebral hemorrhage, the role of autoregulatory disturbances is less clear, but CPA disturbances correlate with worse clinical outcome. Also, in community-acquired bacterial meningitis, CPA dysfunction is frequent and correlates with worse clinical outcome, but autoregulatory management is yet to be evaluated. In this review, we discuss the role of CPA in different types of brain injury and disease, the strengths and limitations of the monitoring methods, the potentials of autoregulatory management, and future directions in the field.