Fluid Balance and Blood Volume Measurement after Aneurysmal Subarachnoid Hemorrhage

Sodium and Its Impact on Outcome After Aneurysmal Subarachnoid Hemorrhage in Patients With and Without Delayed Cerebral Ischemia

OBJECTIVES

To perform a detailed examination of sodium levels, hyponatremia and sodium fluctuations, and their association with delayed cerebral ischemia (DCI) and poor outcome after aneurysmal subarachnoid hemorrhage (aSAH).

DESIGN

An observational cohort study from a prospective SAH Registry.

SETTING

Tertiary referral center focused on SAH treatment in the Amsterdam metropolitan area.

PATIENTS

A total of 964 adult patients with confirmed aSAH were included between 2011 and 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 277 (29%) developed DCI. Hyponatremia occurred significantly more often in DCI patients compared with no-DCI patients (77% vs. 48%). Sodium levels, hyponatremia, hypernatremia, and sodium fluctuations did not predict DCI. However, higher sodium levels were significantly associated with poor outcome in DCI patients (DCI onset -7, DCI +0, +1, +2, +4, +5, +8, +9 d), and in no-DCI patients (postbleed day 6-10 and 12-14). Also, hypernatremia and greater sodium fluctuations were significantly associated with poor outcome in both DCI and no-DCI patients.

CONCLUSIONS

Sodium levels, hyponatremia, and sodium fluctuations were not associated with the occurrence of DCI. However, higher sodium levels, hypernatremia, and greater sodium fluctuations were associated with poor outcome after aSAH irrespective of the presence of DCI. Therefore, sodium levels, even with mild changes in levels, warrant close attention.

Early Goal-directed Therapy During Endovascular Coiling Procedures Following Aneurysmal Subarachnoid Hemorrhage: A Pilot Prospective Randomized Controlled Study

BACKGROUND

Maintenance of euvolemia and cerebral perfusion are recommended for the prevention of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (aSAH). We conducted a pilot randomized controlled study to assess the feasibility and efficacy of goal-directed therapy (GDT) to correct fluid and hemodynamic derangements during endovascular coiling in patients with aSAH.

METHODS

This study was conducted between November 2015 and February 2019 at a single tertiary center in Canada. Adult patients with aSAH within 5 days of aneurysm rupture were randomly assigned to receive either GDT or standard therapy during endovascular coiling. The incidence of dehydration at presentation and the efficacy of GDT were evaluated.

RESULTS

Forty patients were allocated to receive GDT (n=21) or standard therapy (n=19). Sixty percent of all patients were found to have dehydration before the coiling procedure commenced. Compared with standard therapy, GDT reduced the duration of intraoperative hypovolemia (mean difference 37.6 [95% confidence interval, 6.2-37.4] min, P=0.006) and low cardiac index (mean difference 30.7 [95% confidence interval, 9.5-56.9] min, P=0.035). There were no differences between the 2 treatment groups with respect to the incidence of vasospasm, stroke, death, and other complications up to postoperative day 90.

CONCLUSIONS

A high proportion of aSAH patients presented at the coiling procedure with dehydration and a low cardiac output state; these derangements were more likely to be corrected if the GDT algorithm was used. Compared with standard therapy, use of the GDT algorithm resulted in earlier recognition and more consistent treatment of dehydration and hemodynamic derangement during endovascular coiling.

Hemodynamic Monitoring in Patients With Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

Aneurysmal subarachnoid hemorrhage (aSAH) often causes cardiopulmonary dysfunction. Therapeutic strategies can be guided by standard (invasive arterial/central venous pressure measurements, fluid balance assessment), and/or advanced (pulse index continuous cardiac output, pulse dye densitometry, pulmonary artery catheterization) hemodynamic monitoring. We conducted a systematic review and meta-analysis of the literature to determine whether standard compared with advanced hemodynamic monitoring can improve patient management and clinical outcomes after aSAH. A literature search was performed for articles published between January 1, 2000 and January 1, 2019. Studies involving aSAH patients admitted to the intensive care unit and subjected to any type of hemodynamic monitoring were included. A total of 14 studies were selected for the qualitative synthesis and 3 randomized controlled trials, comparing standard versus advanced hemodynamic monitoring, for meta-analysis. The incidence of delayed cerebral ischemia was lower in the advanced compared with standard hemodynamic monitoring group (relative risk [RR]=0.71, 95% confidence interval [CI]=0.52-0.99; P=0.044), but there were no differences in neurological outcome (RR=0.83, 95% CI=0.64-1.06; P=0.14), pulmonary edema onset (RR=0.44, 95% CI=0.05-3.92; P=0.46), or fluid intake (mean difference=-169 mL; 95% CI=-1463 to 1126 mL; P=0.8) between the 2 groups. In summary, this systematic review and meta-analysis found only low-quality evidence to support the use of advanced hemodynamic monitoring in selected aSAH patients. Because of the small number and low quality of studies available for inclusion in the review, further studies are required to investigate the impact of standard and advanced hemodynamic monitoring-guided management on aSAH outcomes.

Urea-Creatinine Ratio (UCR) After Aneurysmal Subarachnoid Hemorrhage: Association of Protein Catabolism with Complication Rate and Outcome

OBJECTIVE

The urea-creatinine ratio (UCR) has been proposed as potential biomarker for critical illness-associated catabolism. Its role in the context of aneurysmal subarachnoid hemorrhage (aSAH) remains to be elucidated, which was the aim of the present study.

METHODS

We enrolled 66 patients with aSAH with normal renal function and 36 patients undergoing elective cardiac surgery as a control group for the effects of surgery. In patients with aSAH, the predictive or diagnostic value of early (day 0-2) and critical (day 5-7) UCRs was assessed with regard to delayed cerebral ischemia (DCI), DCI-related infarction, and clinical outcome after 12 months.

RESULTS

Preoperatively, UCR was similar both groups. Within 2 days postoperatively, UCRs increased significantly in patients in the elective cardiac surgery group (P < 0.001) but decreased back to baseline on day 5-7 (P = 0.245), whereas UCRs in patients with aSAH increased to significantly greater levels on day 5-7 (P = 0.028). Greater early or critical UCRs were associated with poor clinical outcomes (P = 0.015) or DCI (P = 0.011), DCI-related infarction (P = 0.006), and poor clinical outcomes (P < 0.001) respectively. In multivariate analysis, there was an independent association between greater early UCRs and poor clinical outcomes (P = 0.026).

CONCLUSIONS

In this exploratory study of UCR in the context of aSAH, greater early values were predictive for a poor clinical outcome after 12 months, whereas greater critical values were associated with DCI, DCI-related infarctions, and poor clinical outcomes. The clinical implications as well as the pathophysiologic relevance of protein catabolism should be explored further in the context of aSAH.

Bioreactance-Based Noninvasive Fluid Responsiveness and Cardiac Output Monitoring: A Pilot Study in Patients with Aneurysmal Subarachnoid Hemorrhage and Literature Review

Management of volume status, arterial blood pressure, and cardiac output are core elements in approaching the patients with aneurysmal subarachnoid hemorrhage (SAH). For the prevention and treatment of delayed cerebral ischemia (DCI), euvolemia is advocated and caution is made towards the avoidance of hypervolemia. Induced hypertension and cardiac output augmentation are the mainstays of medical management during active DCI, whereas the older triple-H paradigm has fallen out of favor due to lack of demonstrable physiological or clinical benefits and serious concern for adverse effects such as pulmonary edema and multiorgan system dysfunction. Furthermore, insight into clinical hemodynamics of patients with SAH becomes salient when one considers the frequently associated cardiac and pulmonary manifestations of the disease such as SAH-associated cardiomyopathy and neurogenic pulmonary edema. In terms of fluid and volume targets, less attention has been paid to dynamic markers of fluid responsiveness despite the well-established, in the general critical care literature, superiority of these as compared to traditionally used static markers such as central venous pressure (CVP). Based on this literature and sound pathophysiologic reasoning, reliance on static markers (such as CVP) is unjustified when one attempts to assess strategies augmenting stroke volume (SV), arterial blood pressure, and oxygen delivery. There are several options for continuous bedside cardiorespiratory monitoring and optimization of SAH patients. We, here, review a noninvasive monitoring technique based on thoracic bioreactance and focusing on continuous cardiac output and fluid responsiveness markers.

High Early Fluid Input After Aneurysmal Subarachnoid Hemorrhage: Combined Report of Association With Delayed Cerebral Ischemia and Feasibility of Cardiac Output-Guided Fluid Restriction

BACKGROUND

Guidelines on the management of aneurysmal subarachnoid hemorrhage (aSAH) recommend euvolemia, whereas hypervolemia may cause harm. We investigated whether high early fluid input is associated with delayed cerebral ischemia (DCI), and if fluid input can be safely decreased using transpulmonary thermodilution (TPT).

METHODS

We retrospectively included aSAH patients treated at an academic intensive care unit (2007-2011; cohort 1) or managed with TPT (2011-2013; cohort 2). Local guidelines recommended fluid input of 3 L daily. More fluids were administered when daily fluid balance fell below +500 mL. In cohort 2, fluid input in high-risk patients was guided by cardiac output measured by TPT per a strict protocol. Associations of fluid input and balance with DCI were analyzed with multivariable logistic regression (cohort 1), and changes in hemodynamic indices after institution of TPT assessed with linear mixed models (cohort 2).

RESULTS

Cumulative fluid input 0 to 72 hours after admission was associated with DCI in cohort 1 (n=223; odds ratio [OR] 1.19/L; 95% confidence interval 1.07-1.32), whereas cumulative fluid balance was not. In cohort 2 (23 patients), using TPT fluid input could be decreased from 6.0 ± 1.0 L before to 3.4 ± 0.3 L; P = .012), while preload parameters and consciousness remained stable.

CONCLUSION

High early fluid input was associated with DCI. Invasive hemodynamic monitoring was feasible to reduce fluid input while maintaining preload. These results indicate that fluid loading beyond a normal preload occurs, may increase DCI risk, and can be minimized with TPT.

Transpulmonary thermodilution monitoring-guided hemodynamic management improves cognitive function in patients with aneurysmal subarachnoid hemorrhage: a prospective cohort comparison

BACKGROUND

The effects of goal-directed hemodynamic management using transpulmonary thermodilution (TPT) monitor on the cognitive function of patients with aneurysmal subarachnoid hemorrhage (aSAH) remain unclear. The present study aimed to determine whether hemodynamic management with TPT monitor provides better cognitive function compared with standard hemodynamic management.

METHODS

Patients with aSAH who were admitted to the intensive care unit in 2016 were assigned to cohort 1, and those admitted in 2017 were assigned to cohort 2. In cohort 1, hemodynamic and fluid management was performed in accordance with the traditional pressure-based hemodynamic parameters and clinical examination, whereas in cohort 2, it was performed in accordance with the TPT monitor-measured flow-based parameters. The incidence of delayed cerebral ischemia (DCI) and pulmonary edema (PE) was determined. The functional outcome of patients was assessed using the modified Rankin scale (mRS) score and Montreal cognitive assessment (MoCA) test at 1 year following aSAH.

RESULTS

Cohort 1 included 45 patients and cohort 2 included 39 patients who completed the trial. The incidence of DCI (38% versus 26%) and PE (11% versus 3%) was comparable between the cohorts (p > 0.05). The mRS score was similar between the cohorts (p = 0.11). However, the MoCA score was 20.2 (19.2-21.4) and 23.5 (22.2-24.8) in cohort 1 and cohort 2, respectively (p < 0.001). Accordingly, the occurrence of poor MoCA score (38% versus 18%) was significantly lower in cohort 2 (p = 0.045).

CONCLUSIONS

TPT monitor-based hemodynamic management provides better cognitive outcome than standard hemodynamic management in patients with aSAH.

Positive fluid balance is associated with increased in-hospital mortality in patients with intracerebral hemorrhage

Objective: This study aimed to investigate the association between fluid balance (FB) and in-hospital mortality in patients with intracerebral hemorrhage (ICH).Methods: Data were extracted from the online database Multi-parameter Intelligent Monitoring in Intensive Care III. Patients were divided into two groups according to the FB status at 48 hours after intensive care unit (ICU) admission: negative and positive 48-hour FB groups. The primary outcome was in-hospital mortality.Results: Data of 1407 patients were analyzed. Linear spline function in logistic models showed significant association between the volume of positive FB and in-hospital mortality (odds ratio (OR) 1.006; 95% CI: 1.002-1.010), while the association between the volume of negative FB and in-hospital mortality was non-significant. For interpretation, FB was further divided into four quartiles. Referred to Q1, the OR of in-hospital mortality stepwise increased from Q2 (OR, 1.11; 95% CI: 0.72-1.68) to Q4 (OR, 1.68; 95% CI: 1.13-2.48). A similar association was also found between FB and Glasgow coma scale at ICU discharge.Conclusions: In patients with ICH, increased volume of positive FB was associated with higher in-hospital mortality while the volume of negative FB was not. Whether maintaining a zero FB status is a beneficial strategy needs further investigation.

Pre-operative haemodynamic monitoring and resuscitation in hip fracture patients: Protocol for a prospective observational study

BACKGROUND

In a frail patient group often suffering from dehydration, hip fracture is potentially fatal partly because of the blood loss and thus deteriorated circulation. An important goal for haemodynamic monitoring and resuscitation is early detection of insufficient tissue perfusion. "The peripheral perfusion index" reflects changes in peripheral perfusion and blood volume. We hypothesize that hip fracture patients are hypovolaemic with poor peripheral perfusion and accordingly respond to controlled fluid resuscitation. The peripheral perfusion index might reflect restricted tissue perfusion in spite of stable central haemodynamic variables.

METHODS

This prospective observational study assess to what extend hip fracture patients suffer from hypovolaemia and respond to a stroke volume-guided fluid challenge. The secondary objectives are to evaluate correlation between the non-invasive peripheral perfusion index and minimally invasive measures of stroke volume, changes in blood volume and near-infrared spectroscopy determined tissue- and cerebral oxygenation and to compare results to prevalence of post-operative complications including mortality. We will include 50 patients (>65 years) presenting a hip fracture and treated in a multimodal fast-track regimen when written informed consent is available.

DISCUSSION

This is likely the first study to address pre-operative haemodynamic monitoring and resuscitation in hip fracture patients where adequate resuscitation is easily missed. We aim to evaluate feasibility of pre-operative stroke volume-guided haemodynamic optimization in the context of minimally- and non-invasive monitoring of peripheral perfusion and measure of blood volume.

High Early Fluid Input After Aneurysmal Subarachnoid Hemorrhage: Combined Report of Association With Delayed Cerebral Ischemia and Feasibility of Cardiac Output-Guided Fluid Restriction

BACKGROUND

Guidelines on the management of aneurysmal subarachnoid hemorrhage (aSAH) recommend euvolemia, whereas hypervolemia may cause harm. We investigated whether high early fluid input is associated with delayed cerebral ischemia (DCI), and if fluid input can be safely decreased using transpulmonary thermodilution (TPT).

METHODS

We retrospectively included aSAH patients treated at an academic intensive care unit (2007-2011; cohort 1) or managed with TPT (2011-2013; cohort 2). Local guidelines recommended fluid input of 3 L daily. More fluids were administered when daily fluid balance fell below +500 mL. In cohort 2, fluid input in high-risk patients was guided by cardiac output measured by TPT per a strict protocol. Associations of fluid input and balance with DCI were analyzed with multivariable logistic regression (cohort 1), and changes in hemodynamic indices after institution of TPT assessed with linear mixed models (cohort 2).

RESULTS

Cumulative fluid input 0 to 72 hours after admission was associated with DCI in cohort 1 (n=223; odds ratio [OR] 1.19/L; 95% confidence interval 1.07-1.32), whereas cumulative fluid balance was not. In cohort 2 (23 patients), using TPT fluid input could be decreased from 6.0 ± 1.0 L before to 3.4 ± 0.3 L; P = .012), while preload parameters and consciousness remained stable.

CONCLUSION

High early fluid input was associated with DCI. Invasive hemodynamic monitoring was feasible to reduce fluid input while maintaining preload. These results indicate that fluid loading beyond a normal preload occurs, may increase DCI risk, and can be minimized with TPT.

Management of patients with aneurysmal subarachnoid haemorrhage

PURPOSE OF REVIEW

Outcome of patients with aneurysmal subarachnoid haemorrhage (ASAH) has improved, but is still poor. After the introduction of endovascular treatment of intracranial aneurysms, much attention has been given to indications for and advances in endovascular and microneurosurgical techniques to occlude aneurysms, but management of patients with ASAH encompasses much more than occluding the aneurysm.

RECENT FINDINGS

This review describes recent advances in diagnosis and general management of ASAH and in knowledge and medical treatment of delayed cerebral ischaemia and rebleeding.

SUMMARY

In patients with a head computed tomography scan performed less than 6 h after headache onset and reported negative by a staff radiologist, lumbar puncture can be withheld. Patients with ASAH should preferably be treated in a tertiary care centre that treats more than 100 ASAH patients per year. Currently, the only treatment strategy to reduce the risk of delayed cerebral ischaemia remains nimodipine; there is no place for statins or magnesium sulphate, nor for lumbar drainage. Hypervolaemia and induced hypertension may be less beneficial than presumed, and further trials are urgently needed. Very early and short treatment with antifibrinolytic drugs may also be beneficial, but data from ongoing trials should be awaited before this treatment strategy can be implemented.

Fluid management of the neurological patient: a concise review

Maintenance fluids in critically ill brain-injured patients are part of routine critical care. Both the amounts of fluid volumes infused and the type and tonicity of maintenance fluids are relevant in understanding the impact of fluids on the pathophysiology of secondary brain injuries in these patients. In this narrative review, current evidence on routine fluid management of critically ill brain-injured patients and use of haemodynamic monitoring is summarized. Pertinent guidelines and consensus statements on fluid management for brain-injured patients are highlighted. In general, existing guidelines indicate that fluid management in these neurocritical care patients should be targeted at euvolemia using isotonic fluids. A critical appraisal is made of the available literature regarding the appropriate amount of fluids, haemodynamic monitoring and which types of fluids should be administered or avoided and a practical approach to fluid management is elaborated. Although hypovolemia is bound to contribute to secondary brain injury, some more recent data have emerged indicating the potential risks of fluid overload. However, it is acknowledged that many factors govern the relationship between fluid management and cerebral blood flow and oxygenation and more research seems warranted to optimise fluid management and improve outcomes.

Neurocritical care update

This update comprises six important topics under neurocritical care that require reevaluation. For post-cardiac arrest brain injury, the evaluation of the injury and its corresponding therapy, including temperature modulation, is required. Analgosedation for target temperature management is an essential strategy to prevent shivering and minimizes endogenous stress induced by catecholamine surges. For severe traumatic brain injury, the diverse effects of therapeutic hypothermia depend on the complicated pathophysiology of the condition. Continuous electroencephalogram monitoring is an essential tool for detecting nonconvulsive status epilepticus in the intensive care unit (ICU). Neurocritical care, including advanced hemodynamic monitoring, is a fundamental approach for delayed cerebral ischemia following subarachnoid hemorrhage. We must be mindful of the high percentage of ICU patients who may develop sepsis-associated brain dysfunction.

Poor outcome is associated with less negative fluid balance in patients with aneurysmal subarachnoid hemorrhage treated with prophylactic vasopressor-induced hypertension

Background

Aneurysmal subarachnoid hemorrhage (SAH) is a serious condition associated with high mortality rates and long-term disability. We investigated the impact of fluid balance on neurologic outcome after adjustment for possible confounders related to intensive care therapy and extra-cerebral organ failure during the early phase after SAH.

Methods

In this retrospective study, we analyzed data from all 142 adult patients admitted to our university hospital surgical intensive care unit (ICU) with SAH between March 2004 and November 2010.

Results

The mean patient age was 54 ± 14 years, 62.7 % were female, and the median Hunt and Hess score was 3. The proportions of patients with poor outcome (Glasgow Outcome Score ≤3) were 58.4, 54.2, and 52.1 % at 3, 6, and 12 months, respectively, after the SAH. The ICU and hospital mortality rates were both 12.7 %, and the median lengths of stay in the ICU and the hospital were 16 (IQ 7–25) and 26 (IQ 18–34) days, respectively. In multivariable analysis, older age and greater cumulative fluid balance within the first 7 days in the ICU were independently associated with a greater risk of poor outcome.

Conclusion

In this cohort of patients, older age and greater cumulative fluid balance were independently associated with a greater risk of poor outcome up to 1 year after the initial insult. Our data suggest that mild hypovolemia may be beneficial in the management of these patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-016-0128-6) contains supplementary material, which is available to authorized users.

Assessment of circulating blood volume with fluid administration targeting euvolemia or hypervolemia

BACKGROUND

The occurrence of hypovolemia in the setting of cerebral vasospasm reportedly increases the risk for delayed ischemic neurologic deficits. Few studies have objectively assessed blood volume (BV) in response to fluid administration targeting normovolemia (NV) or hypervolemia (HV) and none have done so with crystalloids alone. The primary purpose was to evaluate the BV of patients with SAH receiving crystalloid fluid administration targeting NV or HV.

METHODS

The University of Washington IRB approved the study. Prospectively collected data was obtained from patients enrolled in a clinical trial and a concurrent group of patients who received IV fluids during the ICU stay. We defined a normovolemia (NV) and hypervolemia (HV) group based on the cumulative amount of IV fluid administered in mL/kg from ICU admission to day 5; ≥30-60 mL/kg/day (NV) and ≥60 mL/kg/day (HV), respectively. In a subgroup of patients, BV was measured on day 5 post ictus using iodinated (131)I-labeled albumin injection and the BVA-100 (Daxor Corp, New York, NY). Differences between the NV and HV groups were compared using Student's t-test with assumption for unequal variance.

RESULTS

Twenty patients in the NV and 19 in the HV groups were included. The HV group received more fluid and had a higher fluid balance than the NV group. The subgroup of patients in whom BV was measured on day 5 (n = 19) was not different from the remainder of the cohort with respect to the total amount of administered fluid and net cumulative fluid balance by day 5. BV was not different between the two groups and varied widely.

CONCLUSIONS

Routinely targeting prophylactic HV using crystalloids does not result in a higher circulating BV compared to targeting NV, but the possibility of clinically unrecognized hypovolemia remains.

Positive Fluid Balance Is Associated With Poor Outcomes in Subarachnoid Hemorrhage

BACKGROUND

Strict maintenance of normovolemia is standard of care in the treatment of aneurysmal subarachnoid hemorrhage (aSAH), and induced hypervolemia is often used to treat delayed cerebral ischemia from vasospasm. We tested the hypothesis that positive fluid balance could adversely affect clinical outcomes in aSAH.

METHODS

We reviewed 288 patients with aSAH admitted to the Neuroscience Intensive Care Unit (NICU) from October 2001 to June 2011. We collected data on fluid balance during NICU stay, clinical and radiographic evidence of vasospasm, cardiopulmonary complications, and functional outcomes by modified Rankin Scale (mRS) on follow-up (mean 8 ± 8 months). Poor functional outcome was defined as an mRS score 3-6. Associations of variables of interest with outcome were assessed using univariable and multivariable logistic regression. Propensity scores were estimated to account for imbalances between patients with positive versus negative fluid balance and were included in multivariable models.

RESULTS

Average net fluid balance during the NICU stay was greater in patients with poor functional outcome (3.52 ± 5.51 L versus -.02 ± 5.30 L in patients with good outcome; P < .001). On multivariate analysis, positive fluid balance (P = .002) was independently associated with poor functional outcome along with World Federation of Neurosurgical Societies grade (P < .001), transfusion (P = .003), maximum glucose (P = .005), and radiological evidence of cerebral infarction (P = .008). After regression adjustment with propensity scores, the association of positive fluid balance with poor functional outcome remained significant (odds ratio, 1.18; 95% confidence interval, 1.08-1.29; P < .001).

CONCLUSIONS

Greater positive net fluid balance is independently associated with poorer functional outcome in patients with aSAH.

Rescue therapy for refractory vasospasm after subarachnoid hemorrhage

Vasospasm and delayed cerebral ischemia remain to be the common causes of increased morbidity and mortality after aneurysmal subarachnoid hemorrhage. The majority of clinical vasospasm responds to hemodynamic augmentation and direct vascular intervention; however, a percentage of patients continue to have symptoms and neurological decline. Despite suboptimal evidence, clinicians have several options in treating refractory vasospasm in aneurysmal subarachnoid hemorrhage (aSAH), including cerebral blood flow enhancement, intra-arterial manipulations, and intra-arterial and intrathecal infusions. This review addresses standard treatments as well as emerging novel therapies aimed at improving cerebral perfusion and ameliorating the neurologic deterioration associated with vasospasm and delayed cerebral ischemia.

The effects of fluid balance and colloid administration on outcomes in patients with aneurysmal subarachnoid hemorrhage: a propensity score-matched analysis

BACKGROUND

Delayed ischemic neurological deficit (DIND) following aneurysmal subarachnoid hemorrhage (SAH) remains a significant cause of mortality and disability. The administration of colloids and the induction of a positive fluid balance during the vasospasm risk period remain controversial. Here, we compared DIND and outcomes among propensity score-matched cohorts who did and did not receive colloids and also tested the effect of a positive fluid balance on these endpoints.

METHODS

Exploratory analysis was performed on 413 patients enrolled in CONSCIOUS-1, a prospective randomized trial of clazosentan for the prevention of angiographic vasospasm. Propensity score matching was performed on the basis of age, gender, pre-existing heart conditions, hypertension, nicotine use, World Federation of Neurosurgical Societies scores, aneurysm location, clazosentan treatment, subarachnoid clot burden, and severity of angiographic vasospasm. Inferential statistics were used for group-wise comparisons.

RESULTS

One hundred twenty-three subjects were matched (41 received colloids, whereas 82 did not). The covariate balance and propensity score distributions were acceptable. There was no difference between the groups with respect to DIND (17 vs. 22%; p = 0.64) or the presence (48 vs. 51%; p = 0.71) or volume of delayed infarcts (volume >7.5 cm3; 62 vs. 48%; p = 0.41). Similarly, no differences were found on multivariate analysis between patients who did and did not have a positive fluid balance, although patients with severe angiographic vasospasm had more delayed infarcts with a negative fluid balance (p = 0.01). Among all subjects, the administration of colloids and a positive fluid balance were associated with worse outcomes on the NIHSS (p = 0.04) and modified Rankin (p = 0.02) scales, respectively.

CONCLUSIONS

Colloid administration and induction of a positive fluid balance during the vasospasm risk period may be associated with poor outcomes in specific patient groups. Patient selection is of utmost importance when managing the fluid status of patients with aneurysmal SAH.

Early brain injury and subarachnoid hemorrhage: Where are we at present?

The current era has adopted many new innovations in nearly every aspect of management of subarachnoid hemorrhage (SAH); however, the neurological outcome has still not changed significantly. These major therapeutic advances mainly addressed the two most important sequels of the SAH-vasospasm and re-bleed. Thus, there is a possibility of some different pathophysiological mechanism that would be responsible for causing poor outcome in these patients. In this article, we have tried to compile the current role of this different yet potentially treatable pathophysiological mechanism in post-SAH patients. The main pathophysiological mechanism for the development of early brain injury (EBI) is the apoptotic pathways. The macro-mechanism includes increased intracranial pressure, disruption of the blood-brain barrier, and finally global ischemia. Most of the treatment strategies are still in the experimental phase. Although the role of EBI following SAH is now well established, the treatment modalities for human patients are yet to be testified.

Managing subarachnoid hemorrhage in the neurocritical care unit

Patients with aneurysmal subarachnoid hemorrhage who survive the initial hemorrhage require complex interventions to occlude the aneurysm, typically followed by a prolonged intensive care unit and hospital course to manage the complications that follow. Much of the morbidity and mortality from this disease happens in delayed fashion in the neurocritical care unit. Despite progress made in the last decades, much remains to be understood about this disease and how to best manage these patients. This article provides a review of current evidence and the authors' experience, aimed at providing practical aid to those caring for patients with this disease.

Global end-diastolic volume is associated with the occurrence of delayed cerebral ischemia and pulmonary edema after subarachnoid hemorrhage

Predictive variables of delayed cerebral ischemia (DCI) and pulmonary edema following subarachnoid hemorrhage (SAH) remain unknown. We aimed to determine associations between transpulmonary thermodilution-derived variables and DCI and pulmonary edema occurrence after SAH. We reviewed 34 consecutive SAH patients monitored by the PiCCO system. Six patients developed DCI at 7 days after SAH on average; 28 did not (non-DCI). We compared the variable measures for 1 day before DCI occurred (DCI day -1) in the DCI group and 6 days after SAH (non-DCI day -1) in the non-DCI group for control. The mean value of the global end-diastolic volume index (GEDI) for DCI day -1 was lower than that for non-DCI day -1 (676 ± 65 vs. 872 ± 85 mL/m, P = 0.04). Central venous pressure (CVP) was not significantly different (7.8 ± 3.1 vs. 9.4 ± 1.9 cm H2O, P = 0.45). At day -1 for both DCI and non-DCI, 11 patients (32%) had pulmonary edema. Global end-diastolic volume index was significantly higher in patients with pulmonary edema than in those without this condition (947 ± 126 vs. 766 ± 81 mL/m, P = 0.02); CVP was not significantly different (8.7 ± 2.8 vs. 9.2 ± 2.1 cm H2O, P = 0.78). Although significant correlation was found between extravascular lung water (EVLW) measures and GEDI (r = 0.58, P = 0.001), EVLW and CVP were not correlated (r = 0.03, P = 0.88). Thus, GEDI might be associated with DCI occurrence and EVLW accumulation after SAH.

The association between fluid balance and outcomes after subarachnoid hemorrhage

BACKGROUND

We sought to determine the association between early fluid balance and neurological/vital outcome of patients with subarachnoid hemorrhage.

METHODS

Hospital admission, imaging, ICU and outcome data were retrospectively collected from the medical records of adult patients with aneurysmal SAH admitted to a level-1 trauma and stroke referral center during a 5-year period. Two groups were identified based on cumulative fluid balance by ICU day 3: (i) patients with a positive fluid balance (n = 221) and (ii) patients with even or negative fluid balance (n = 135). Multivariable logistic regression was used to adjust for age, Hunt-Hess and Fisher scores, mechanical ventilation and troponin elevation (>0.40 ng/ml) at ICU admission. The primary outcome was a composite of hospital mortality or new stroke.

RESULTS

Patients with positive fluid balance had worse admission GCS and Hunt-Hess score, and by ICU day 3 had cumulatively received more IV fluids, but had less urine output when compared with the negative fluid balance group. There was no difference in the odds of hospital death or new stroke (adjusted OR: 1.47, 95%CI: 0.85, 2.54) between patients with positive and negative fluid balance. However, positive fluid balance was associated with increased odds of TCD vasospasm (adjusted OR 2.25, 95%CI: 1.37, 3.71) and prolonged hospital length of stay.

CONCLUSIONS

Although handling of IV fluid administration was not an independent predictor of mortality or new stroke, patients with early positive fluid balance had worse clinical presentation and had greater resource use during the hospital course.

Advanced hemodynamic monitoring: principles and practice in neurocritical care

Advanced hemodynamic monitoring is necessary for many patients with acute brain and/or spinal cord injury. Optimizing cerebral and systemic physiology requires multi-organ system function monitoring. Hemodynamic manipulations are cardinal among interventions to regulate cerebral perfusion pressure and cerebral blood flow. The pulmonary artery catheter is not any more the sole tool available; less invasive and potentially more accurate methodologies have been developed and employed in the operating room and among diverse critically ill populations. These include transpulmonary thermodilution, arterial pressure pulse contour, and waveform analysis and bedside critical care ultrasound. A thorough understanding of hemodynamics and of the available monitoring modalities is an essential skill for the neurointensivist.

Monitoring of volume status after subarachnoid hemorrhage

Hypovolemia is common after subarachnoid hemorrhage, and fluid imbalance negatively affects clinical outcome. Standard bedside volume measures fail to adequately assess fluid status after subarachnoid hemorrhage. An electronic literature search of original research studies evaluating fluid status after subarachnoid hemorrhage was conducted for English language articles published through October 2010. Sixteen articles were included in this review, with seven articles produced by two research groups. These studies highlight that fluid status is often affected and difficult to assess after subarachnoid hemorrhage. Both non-invasive and invasive monitors may be used to more accurately define volume status.

In vivo multispectral photoacoustic and photothermal flow cytometry with multicolor dyes: a potential for real-time assessment of circulation, dye-cell interaction, and blood volume

Recently, photoacoustic (PA) flow cytometry (PAFC) has been developed for in vivo detection of circulating tumor cells and bacteria targeted by nanoparticles. Here, we propose multispectral PAFC with multiple dyes having distinctive absorption spectra as multicolor PA contrast agents. As a first step of our proof-of-concept, we characterized high-speed PAFC capability to monitor the clearance of three dyes (Indocyanine Green [ICG], Methylene Blue [MB], and Trypan Blue [TB]) in an animal model in vivo and in real time. We observed strong dynamic PA signal fluctuations, which can be associated with interactions of dyes with circulating blood cells and plasma proteins. PAFC demonstrated enumeration of circulating red and white blood cells labeled with ICG and MB, respectively, and detection of rare dead cells uptaking TB directly in bloodstream. The possibility for accurate measurements of various dye concentrations including Crystal Violet and Brilliant Green were verified in vitro using complementary to PAFC photothermal (PT) technique and spectrophotometry under batch and flow conditions. We further analyze the potential of integrated PAFC/PT spectroscopy with multiple dyes for rapid and accurate measurements of circulating blood volume without a priori information on hemoglobin content, which is impossible with existing optical techniques. This is important in many medical conditions including surgery and trauma with extensive blood loss, rapid fluid administration, and transfusion of red blood cells. The potential for developing a robust clinical PAFC prototype that is safe for human, and its applications for studying the liver function are further highlighted.

[Protective measures against cerebral ischemia following subarachnoid hemorrhage: Part 1]

BACKGROUND AND OBJECTIVES

Cerebral vasospasm following aneurysmal subarachnoid hemorrhage contributes significantly to morbidity and mortality. Many studies on the various treatments aimed at preventing cerebral vasospasm have been carried out, but evidence of efficacy is limited. Our aim was to review the literature on the various therapies for which there is scientific evidence of protection against cerebral vasospasm following aneurysmal subarachnoid hemorrhage.

METHODS

MEDLINE search (1950 to the october 2009) and review of articles found on the prevention of cerebral vasospasm following aneurysmal subarachnoid hemorrhage. The search was restricted to articles in English, French, and Spanish. The keywords were cerebral vasospasm, subarachnoid hemorrhage, therapy, nimodipine, triple H, clazosentan, statins, and magnesium in addition to the word forms derived from them. We also searched manually for references cited in the selected articles. A title was included if it was a randomized controlled trial, meta-analysis, nonrandomized clinical trial, descriptive study, observational study with statistical analysis, opinion article, or expert review.

RESULTS

Part 1 analyzed treatment with calcium antagonists and triple-H therapy (hypertension, hemodilution, and hypervolemia). Part 2 analyzed new therapies such as clazosentan, magnesium, and statins. A total of 597 titles were located; 283 were initially selected. The 61 articles finally selected for review were of the following types: 2 opinion articles, 21 randomized controlled trials, 22 expert review articles, 3 meta-analyses, 4 nonrandomized clinical trials, 1 descriptive study, and 5 observational studies with statistical analysis. Three studies (2 meta-analyses and 1 randomized controlled trial) demonstrated that nimodipine use confers benefits (reduced morbidity and mortality) for patients with aneurysmatic subarachnoid hemorrhage. Statistically significant clinical benefits could not be demonstrated for the other drugs (clazosentan, statins, and magnesium).

CONCLUSIONS

Insufficient evidence is available to support the use of the triple-H therapy, clazosentan, statins, or magnesium sulfate for the prevention of cerebral vasospasm following subarachnoid hemorrhage. Nimodipine is the only preventative treatment that can be recommended.

Hypertension may be the most important component of hyperdynamic therapy in cerebral vasospasm

Although hyperdynamic therapy is an accepted method of treatment of patients with symptomatic cerebral vasospasm after aneurysmal subarachnoid hemorrhage, it remains unproven in large scale trials and controlled studies. Furthermore, methods of hyperdynamic therapy and specific endpoints vary widely. A systematic review of clinical trials of the various techniques of hyperdynamic therapy and their effects on cerebral blood flow found only 11 studies suitable for analysis. Although controlled trials are lacking, there is some evidence to suggest that hypertension is the most promising component of hyperdynamic therapy. These findings support a future randomized trial of induced hypertension in patients with symptomatic cerebral vasospasm.

Pulmonary edema and blood volume after aneurysmal subarachnoid hemorrhage: a prospective observational study

Introduction

Pulmonary edema (PED) is a severe complication after aneurysmal subarachnoid hemorrhage (SAH). PED is often treated with diuretics and a reduction in fluid intake, but this may cause intravascular volume depletion, which is associated with secondary ischemia after SAH. We prospectively studied intravascular volume in SAH patients with and without PED.

Methods

Circulating blood volume (CBV) was determined daily during the first 10 days after SAH by means of pulse dye densitometry. CBV of 60-80 ml/kg was considered normal. PED was diagnosed from clinical signs and characteristic bilateral pulmonary infiltrates on the chest radiograph. We compared CBV, cardiac index, and fluid balance between patients with and without PED with weighted linear regression, taking into account only measurements from the first day after SAH through to the day on which PED was diagnosed. Differences were adjusted for age, bodyweight, and clinical condition.

Results

In total, 102 patients were included, 17 of whom developed PED after a mean of 4 days after SAH. Patients developing PED had lower mean CBV (56.6 ml/kg) than did those without PED (66.8 ml/kg). The mean difference in CBV was -11.3 ml/kg (95% CI, -16.5 to -6.1); adjusted mean difference, -8.0 ml/kg (95% CI, -14.0 to -2.0). After adjusting, no differences were found in cardiac index or fluid balance between patients with and without PED.

Conclusions

SAH patients developing pulmonary edema have a lower blood volume than do those without PED and are hypovolemic. Measures taken to counteract pulmonary edema must be balanced against the risk of worsening hypovolemia.

Trial registration

NTR1255.

Blood volume measurement with indocyanine green pulse spectrophotometry: dose and site of dye administration

Background

(1) To determine the optimal administration site and dose of indocyanine green (ICG) for blood volume measurement using pulse spectrophotometry, (2) to assess the variation in repeated blood volume measurements for patients after subarachnoid hemorrhage and (3) to evaluate the safety and efficacy of this technique in patients who were treated for an intracranial aneurysm.

Methods

Four repeated measurements of blood volume (BV) were performed in random order of bolus dose (10 mg or 25 mg ICG) and venous administration site (peripheral or central) in eight patients admitted for treatment of an intracranial aneurysm. Another five patients with subarachnoid hemorrhage underwent three repeated BV measurements with 25 mg ICG at the same administration site to assess the coefficient of variation.

Findings

The mean ± SD in BV was 4.38 ± 0.88 l (n = 25) and 4.69 ± 1.11 l (n = 26) for 10 mg and 25 mg ICG, respectively. The mean ± SD in BV was 4.59 ± 1.15 l (n = 26) and 4.48 ± 0.86 l (n = 25) for central and peripheral administration, respectively. No significant difference was found. The coefficient of variance of BV measurement with 25 mg of ICG was 7.5% (95% CI: 3–12%).

Conclusions

There is no significant difference between intravenous administration of either 10 or 25 mg ICG, and this can be injected through either a peripheral or central venous catheter. The 7.5% coefficient of variation in BV measurements determines the detectable differences using ICG pulse spectrophotometry.

Which H is the most important in triple-H therapy for cerebral vasospasm?

PURPOSE OF REVIEW

To summarize the recent literature of the hemodynamic management of subarachnoid hemorrhage and cerebral vasospasm, also designated as 'triple-H' therapy, and discuss each component of this management approach individually.

RECENT FINDINGS

Following the publication of a review on circulatory volume expansion in the Cochrane Registry database in 2004 and a meta-analysis in 2003, there are no new randomized trials of triple-H therapy to prevent or treat cerebral vasospasm. However, physiological studies have been reported that contribute to the understanding of some of the components of triple-H therapy.

SUMMARY

There remains a paucity of information regarding the efficacy and safety of triple-H therapy. The complexity in exploring this topic derives not only from the interdependence of the different components of triple-H therapy but also by the limitation in the assessment of hemodynamic variables. However, there is some emerging physiologic data suggesting that normovolemic hypertension may be the component most likely to increase cerebral blood flow after subarachnoid hemorrhage. In contrast, hypervolemic hemodilution is associated with increased complications and might also lower the hemoglobin to excessively low levels.

Nurses' prediction of volume status after aneurysmal subarachnoid haemorrhage: a prospective cohort study

Introduction

Patients who have suffered aneurysmal subarachnoid haemorrhage (SAH) often have derangements in blood volume, contributing to poor outcome. To guide fluid management, regular assessments of volume status must be conducted. We studied the ability of nursing staff to predict hypovolaemia or hypervolaemia, based on their interpretation of available haemodynamic data.

Methods

In a prospective cohort study, intensive care unit and medium care unit nurses, currently treating patients with recent SAH, were asked to predict present volume status. For their assessment they could use all available haemodynamic parameters (for example, heart rate, blood pressure, fluid balance). The nurses' assessments were compared with the actual circulating blood volume (CBV), as measured daily with pulse dye densitometry during the first 10 days after SAH. Normovolaemia was defined as a CBV of 60 to 80 ml/kg body weight; hypovolaemia as CBV under 60 ml/kg; severe hypovolaemia as CBV under 50 ml/kg and hypervolaemia as CBV above 80 ml/kg.

Results

A total of 350 combinations of volume predictions and CBV measurements were obtained in 43 patients. Prediction of hypovolaemia had a sensitivity of 0.10 (95% confidence interval [CI] = 0.06 to 0.16) and a positive predictive value of 0.37 (95% CI = 0.23 to 0.53) for actual hypovolaemia. The prediction of hypervolaemia had a sensitivity of 0.06 (95% CI = 0.01 to 0.16) and a positive predictive value of 0.06 (95% CI = 0.02 to 0.19) for actual hypervolaemia. Mean CBV was significantly lower in instances considered hypervolaemic than in instances considered normovolaemic.

Conclusions

Assessment of haemodynamic condition in patients with SAH by intensive care unit or medium care unit nurses does not adequately predict hypovolaemia or hypervolaemia, as measured using pulse dye densitometry. Fluid therapy after SAH may require guidance with more advanced techniques than interpretation of usual haemodynamic parameters.