Serial blood lactate measurements and its prognostic significance in intensive care unit management of aneurysmal subarachnoid hemorrhage patients

Early Metabolic Disruption and Predictive Biomarkers of Delayed-Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH) is a major cause of complications and death. Here, we set out to identify high-performance predictive biomarkers of DCI and its underlying metabolic disruptions using metabolomics and lipidomics approaches. This single-center prospective observational study enrolled 61 consecutive patients with severe aSAH; among them, 22 experienced a DCI. Nine patients without aSAH were included as validation controls. Blood and cerebrospinal fluid (CSF) were sampled within the first 24 h after admission. We identified a panel of 20 metabolites that, together, showed high predictive performance for DCI. This panel of metabolites included lactate, cotinine, salicylate, 6 phosphatidylcholines, and 4 sphingomyelins. The interplay of the metabolome and the lipidome found between CSF and plasma in our patients underscores that aSAH and its associated DCI complications can extend beyond cerebral implications, with a peripheral dimension as well. As an illustration, early biological disruptions that might explain the subsequent DCI found systemic hypoxia driven mainly by higher blood lactate, arginine, and proline metabolism likely associated with vascular NO and disrupted ceramide/sphingolipid metabolism. We conclude that targeting early peripheral hypoxia preceding DCI could provide an interesting strategy for the prevention of vascular dysfunction.

The Prognostic Role of Lactate Concentrations after Aneurysmal Subarachnoid Hemorrhage

Blood lactate concentrations are often used to assess global tissue perfusion in critically ill patients; however, there are scarce data on lactate concentrations after subarachnoid hemorrhage (SAH). We aimed to assess the prognostic role of serial blood lactate measurements on hospital mortality and neurological outcomes at 3 months after SAH. We reviewed all SAH patients admitted to the intensive care unit from 2007 to 2019 and recorded the highest daily arterial lactate concentration for the first 6 days. Patients with no lactate concentration were excluded. Hyperlactatemia was defined as a blood lactate concentration >2.0 mmol/L. A total of 456 patients were included: 158 (35%) patients died in hospital and 209 (46%) had an unfavorable outcome (UO) at 3 months. The median highest lactate concentration was 2.7 (1.8–3.9) mmol/L. Non-survivors and patients with UO had significantly higher lactate concentrations compared to other patients. Hyperlactatemia increased the chance of dying (OR 4.19 (95% CI 2.38–7.39)) and of having UO in 3 months (OR 4.16 (95% CI 2.52–6.88)) after adjusting for confounding factors. Therefore, initial blood lactate concentrations have prognostic implications in patients with SAH; their role in conjunction with other prognostic indicators should be evaluated in prospective studies.

Serum Lactate Could Predict Mortality in Patients With Spontaneous Subarachnoid Hemorrhage in the Emergency Department

Background: Serum lactate is a useful biomarker for prediction of mortality in critically ill patients. The purpose of this study was to identify if serum lactate could be used as a biomarker for predicting mortality in patients with subarachnoid hemorrhage (SAH) in the emergency department.

Methods: This retrospective study enrolled 189 patients. Baseline demographic data and clinical characteristics of patients were obtained from medical record review. Multiple logistic regression analysis was performed to determine predictor variables significantly associated with mortality. Receiver operating characteristic (ROC) curve analysis was used to evaluate the performance of variables for mortality prediction in SAH.

Results: Using multivariate logistic regression analysis, age [OR 1.05; 95% confidence interval (CI) 1.00–1.10; p = 0.037], Hunt and Hess scale score (OR 3.29; 95% CI 1.62–6.70; p = 0.001), serum lactate level (OR 1.33; 95% CI 1.03–1.74; p = 0.032), and serum glucose level (OR 1.01; 95% CI 1.00–1.02; p = 0.049) predicted overall mortality in SAH. The area under the ROC curve (AUC) value for the use of serum lactate level to predict mortality in SAH was 0.815 (95% CI 0.753–0.868) (p < 0.001).

Conclusion: Serum lactate may be a useful biomarker for the early prediction of mortality in SAH patients in the emergency department.

Early Hyperoxia in The Intensive Care Unit is Significantly Associated With Unfavorable Neurological Outcomes in Patients With Mild-to-Moderate Aneurysmal Subarachnoid Hemorrhage

INTRODUCTION

Although oxygen administration is fundamental in the management of aneurysmal subarachnoid hemorrhage (SAH) patients in the acute stage, hyperoxia has harmful effects. The effects of hyperoxia on neurological outcomes in SAH patients are unclear. We aimed to examine the association of hyperoxia during the first 24 h in the intensive care unit (ICU) with unfavorable neurological outcomes in SAH patients.

METHODS

We retrospectively selected consecutive adult patients admitted to ICU for SAH between January 2009 and April 2018. We defined normoxia during the first 24 h in ICU as PaO2 of 60 mm Hg to 120 mm Hg, mild hyperoxia as PaO2 of 121 mm Hg to 200 mm Hg, moderate hyperoxia as PaO2 of 201 mm Hg to 300 mm Hg, and severe hyperoxia as PaO2 of >300 mm Hg. Univariate and multivariate analyses were performed to examine the association between hyperoxia during the first 24 h in ICU and unfavorable neurological outcomes (i.e., modified Rankin scale score of 3-6 at hospital discharge).

RESULTS

Among 196 SAH patients, 90 had unfavorable neurological outcomes. Hyperoxia was observed in 93.4% of patients. No significant association was observed between unfavorable neurological outcomes and hyperoxia in overall patients. However, we found that early hyperoxia in ICU was significantly associated with unfavorable neurological outcomes in SAH patients with Hunt and Kosnik (H&K) grades I to III (Relative risk, 1.84; 95% confidence interval, 1.10-2.94; P = 0.02).

CONCLUSIONS

Early hyperoxia was not associated with unfavorable neurological outcomes in overall SAH patients, but it was associated with unfavorable neurological outcomes in those with H&K grades I to III.

Using Cerebral Metabolites to Guide Precision Medicine for Subarachnoid Hemorrhage: Lactate and Pyruvate

Subarachnoid hemorrhage (SAH) is one of the deadliest types of strokes with high rates of morbidity and permanent injury. Fluctuations in the levels of cerebral metabolites following SAH can be indicators of brain injury severity. Specifically, the changes in the levels of key metabolites involved in cellular metabolism, lactate and pyruvate, can be used as a biomarker for patient prognosis and tailor treatment to an individual’s needs. Here, clinical research is reviewed on the usefulness of cerebral lactate and pyruvate measurements as a predictive tool for SAH outcomes and their potential to guide a precision medicine approach to treatment.

Association of abnormal carbon dioxide levels with poor neurological outcomes in aneurysmal subarachnoid hemorrhage: a retrospective observational study

Background

In patients with aneurysmal subarachnoid hemorrhage (SAH), an association between hypocapnia and poor clinical outcomes has been reported. However, the optimal arterial carbon dioxide tension (PaCO₂) remains unknown. The present retrospective study aimed to examine the association of abnormal PaCO₂ levels with neurological outcomes and investigate the optimal target PaCO₂ level in patients with SAH.

Methods

We retrospectively selected consecutive adult patients hospitalized in the intensive care unit (ICU) for SAH between January 2009 and April 2017. Univariate and multivariate analyses were performed to identify the independent predictors of unfavorable neurological outcomes (i.e., modified Rankin scale score of 3–6 on hospital discharge).

Results

Among 158 patients with SAH, 73 had unfavorable neurological outcomes. During the first 2 weeks in the ICU, the median number of PaCO₂ measurements per patient was 43. The factors significantly associated with unfavorable neurological outcomes were age, Hunt and Kosnik grade, maximum lactate levels during the first 24 h, and maximum (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.03–1.21; p < 0.01) and minimum PaCO₂ levels (OR, 0.81; 95% CI, 0.72–0.92; p < 0.01). Receiver operating characteristic curve analysis revealed that the cutoff range of PaCO₂ was 30.2–48.3 mmHg. Unfavorable neurological outcomes were noted in 78.8% of patients with PaCO₂ levels outside this range and in 22.8% of patients with PaCO₂ levels within this range.

Conclusions

Both the maximum and minimum PaCO₂ levels during ICU management in patients with SAH were significantly associated with unfavorable neurological outcomes. Further prospective studies are required to validate our findings and explore their clinical implications. Our findings may provide a scientific rationale for these future prospective studies.

Electronic supplementary material

The online version of this article (10.1186/s40560-018-0353-1) contains supplementary material, which is available to authorized users.

Neuroanesthesiology Update

We provide a synopsis of innovative research, recurring themes, and novel experimental findings pertinent to the care of neurosurgical patients and critically ill patients with neurological diseases. We cover the following broad topics: general neurosurgery, spine surgery, stroke, traumatic brain injury, monitoring, and anesthetic neurotoxicity.

Serum Lactic Acid Following Aneurysmal Subarachnoid Hemorrhage Is a Marker of Disease Severity but Is Not Associated With Hospital Outcomes

Background: Following aneurysmal subarachnoid hemorrhage, peripherally-drawn lactic acid has been associated with poor outcomes; however, its clinical significance is unknown. We investigated admission factors and patient outcomes associated with serum lactic acid in this population.

Methods: This was a retrospective observational study of 105 consecutive patients with serum lactate collected within 24 h of admission. Primary objectives were to determine the incidence of admission lactic acidemia, and factors positively and negatively associated with lactate levels. We also sought to determine if admission lactic acidemia was associated with patient outcomes, including vasospasm, delayed cerebral ischemia, mortality, and discharge disposition.

Results: Admission serum lactic acid was elevated in 56 patients (53% of the cohort). Levels were positively associated with Hunt & Hess and modified Fisher grade, glucose, troponin I and white blood cell counts, and negatively associated with GCS and ventilator-free days. Admission lactate was not associated with the development of vasospasm or delayed cerebral ischemia. Patients with elevated lactic acid more often died during hospitalization, and less often were discharged home. After adjusting for other predictors of poor outcome, the adjusted odds of inpatient mortality (OR 0.97, 95% CI 0.79–1.20; p = 0.80) and discharge to home (OR 1.00, 95% CI 0.80–1.26; p = 0.97) was not associated with admission lactic acid.

Conclusions: Early serum lactic acid elevation is common following aneurysmal subarachnoid hemorrhage and is associated with the clinical and radiographic grade of hemorrhage. Levels did not independently predict short-term outcomes when adjusted for established predictors of poor outcome. Further study is needed to determine the clinical significance of peripherally-drawn lactic acid in aneurysmal subarachnoid hemorrhage.

Aneurysmal subarachnoid hemorrhage: intensive care for improving neurological outcome

Background

Aneurysmal subarachnoid hemorrhage is a life-threatening disease requiring neurocritical care. Delayed cerebral ischemia is a well-known complication that contributes to unfavorable neurological outcomes. Cerebral vasospasm has been thought to be the main cause of delayed cerebral ischemia, and although several studies were able to decrease cerebral vasospasm, none showed improved neurological outcomes. Our target is not cerebral vasospasm but improving neurological outcomes. The purpose of this review is to discuss what intensivists should know and can do to improve clinical outcomes in subarachnoid hemorrhage patients.

Main body of the abstract

Delayed cerebral ischemia is thought to be due to not only vasospasm but also multifactorial mechanisms. Additionally, the concept of early brain injury, which occurs within the first 72 h after the hemorrhage, has become an important concern. Increasing sympathetic activity after the hemorrhage is associated with cardiopulmonary complications and poor outcomes. Serum lactate measurement may be a valuable marker reflecting the severity of sympathetic activity. The transpulmonary thermodilution method will bring about an advanced understanding of hemodynamic management. Fever is a well-recognized symptom and targeted temperature management is an anticipated intervention. To avoid hyperglycemia and hypoglycemia, performing moderate glucose control and minimizing glucose variability are important concepts in glycemic management, but the optimal target range remains unknown. Dysnatremia seems to be associated with negative outcomes. It is not clear yet that maintaining normonatremia actively improves neurological outcomes. Optimal duration of intensive care management has not been determined.

Short conclusion

Although we have an advanced understanding of the pathophysiology and clinical characteristics of subarachnoid hemorrhage, there are many controversies in the intensive care unit management of subarachnoid hemorrhage. With an awareness of not only delayed cerebral ischemia but also early brain injury, more attention should be given to various aspects to improve neurological outcomes.