Hemodynamic manipulation in the neuro-intensive care unit: cerebral perfusion pressure therapy in head injury and hemodynamic augmentation for cerebral vasospasm

Hemodynamic management of acute brain injury caused by cerebrovascular diseases: a survey of the European Society of Intensive Care Medicine

BACKGROUND

The optimal hemodynamic targets and management of patients with acute brain injury are not completely elucidated, but recent evidence points to important impact on clinical outcomes. We performed an international survey with the aim to investigate the practice in the hemodynamic targets, monitoring, and management of patients with acute ischemic stroke (AIS), intracranial hemorrhage (ICH) and subarachnoid hemorrhage (SAH).

METHODS

This survey was endorsed by the European Society of Intensive Care (ESICM). An electronic questionnaire of 76 questions divided in 4 sections (general information, AIS, ICH, SAH specific questions) was available between January 2022 to March 2022 on the ESICM website.

RESULTS

One hundred fifty-four healthcare professionals from 36 different countries and at least 98 different institutions answered the survey. Routine echocardiography is routinely performed in 37% of responders in AIS, 34% in ICH and 38% in SAH. Cardiac output monitoring is used in less than 20% of cases by most of the responders. Cardiovascular complications are the main reason for using advanced hemodynamic monitoring, and norepinephrine is the most common drug used to increase arterial blood pressure. Most responders target fluid balance to neutral (62% in AIS, 59% in ICH,44% in SAH), and normal saline is the most common fluid used. Large variability was observed regarding the blood pressure targets.

CONCLUSIONS

Hemodynamic management and treatment in patients with acute brain injury from cerebrovascular diseases vary largely in clinical practice. Further research is required to provide clear guidelines to physicians for the hemodynamic optimization of this group of patients.

Effect of inotropic agents on oxygenation and cerebral perfusion in acute brain injury

Introduction

Tissue hypoxia and insufficient energy delivery is one of the mechanisms behind the occurrence of several complications in acute brain injured patients. Several interventions can improve cerebral oxygenation; however, the effects of inotropic agents remain poorly characterized.

Methods

Retrospective analysis including patients suffering from acute brain injury and monitored with brain oxygen pressure (PbtO2) catheter, in whom inotropic agents were administered according to the decision of the treating physician's decision; PbtO2 values were collected before, 1 and 2 h after the initiation of therapy from the patient data monitoring system. PbtO2 “responders” were patients with a relative increase in PbtO2 from baseline values of at least 20%.

Results

A total of 35 patients were included in this study. Most of them (31/35, 89%) suffered from non-traumatic subarachnoid hemorrhage (SAH). Compared with baseline values [20 (14–24) mmHg], PbtO2 did not significantly increase over time [19 (15–25) mmHg at 1 h and 19 (17–25) mmHg at 2 h, respectively; p = 0.052]. A total of 12/35 (34%) patients were PbtO2 “responders,” in particular if low PbtO2 was observed at baseline. A PbtO2 of 17 mmHg at baseline had a sensibility of 84% and a specificity of 91% to predict a PbtO2 responder. A significant direct correlation between changes in PbtO2 and cardiac output [r = 0.496 (95% CI 0.122 to 0.746), p = 0.01; n = 25] and a significant negative correlation between changes in PbtO2 and cerebral perfusion pressure [r = −0.389 (95% CI −0.681 to −0.010), p = 0.05] were observed.

Conclusions

In this study, inotropic administration significantly increased brain oxygenation in one third of brain injured patients, especially when tissue hypoxia was present at baseline. Future studies should highlight the role of inotropic agents in the management of tissue hypoxia in this setting.

Adopting a cross-scale approach for the deployment of a green infrastructure

The implementation of a Green Infrastructure (GI) involves several actors and governance scales that need adequate knowledge support. The multifunctionality of GI entails the implementation of a cross-scale approach, which combines assessments conducted at different levels and active stakeholder engagement.

This paper provides a methodology to implement a cross-scale approach to support the deployment of a Regional GI. The methodology was tested in Lombardy Region (north-west of Italy), considering three relevant territorial scales and relative strategic and planning policies. The continental level representing the overall policy-context; the regional level, with its key role for guaranteeing landscape coherence and connectivity and the local level where planning actions are effectively designed and implemented. The EU Biodiversity Strategy for 2030 and the EU GI strategy were used as references for the continental level; at the regional level, a proposal of Regional GI was evaluated focusing on two Provinces (Varese and Lecco), three regional parks (Ticino, Adda Nord and Campo dei Fiori). At the local scale, the new development plan of the Municipality of Cassano d'Adda (Milan metropolitan area) was evaluated considering different possible scenarios.

The regional GI was evaluated with respect to the capacity to provide Cultural Ecosystem Services (CES). CES were mapped using the ESTIMAP-recreation model. The model was adapted to the regional and local level with the active engagement of local stakeholders. Additionally, census data were analysed to obtain an overview of the equitable distribution of the CES amongst inhabitants.

Results show that, in 78% of the census blocks of the study area, inhabitants have a high-value recreation resource within 4 km (31% within 4 km and 47% within 300 m). Unmet demand characterises 22% of the census blocks in the study area, clustered in zones with a high population density. The regional GI covers almost completely the two Provinces and the regional parks. In Varese Province: 68% of the territory is included in the regional GI, 82% of the census blocks local demand for recreation opportunities is met, but the population density is higher where the demand is unmet. The Province is characterised by a relatively old population (share of people older than 65 years 23.4%). In Lecco Province, 80% of the territory is included in the regional GI, in 96% of the blocks the local demand is met and the local population is relatively old (share of elderly population 22.12%).

The three regional parks present significant differences, strongly influenced by the territorial context. The Campo dei Fiori Park is almost completely included in the regional GI. The entire local population has nature-based recreation opportunities in their close vicinity. Nevertheless, the population density is very low and citizens are relatively old. The majority of the Parco Adda Nord is included in the regional GI providing recreation opportunities to 90% of the census blocks within the Park boundaries. A total of 70% of Ticino Park is included in the regional GI, where local residents are relatively old (share of elderly population 23.78%) and 90% of local census blocks are close to nature-based opportunities.

At local scale, we explored how the approach can be used to estimate changes in the CES potential provision and how this can be integrated into a site management plan.

This paper demonstrated that the combination of studies in a cross-scale perspective enhances the understanding of GI multifunctionality. It provides a framework to adapt CES mapping models to the local setting with active stakeholders engagement. Moreover, it demonstrates that also highly urbanised areas, such as the Lombardy Region in Italy, can play a role in the deployment of a continental GI and can support biodiversity and nature protection.

Milrinone-Associated Cardiomyopathy and Arrhythmia in Cerebral Vasospasm

BACKGROUND

Milrinone is an inotropic and vasodilatory drug proven safe for use in treatment of cerebral vasospasm. Despite its reported safety profile, its use is not free of side effects. Milrinone-associated cardiomyopathy and arrhythmia can occur in patients with cerebral vasospasm.

CASE DESCRIPTION

This is a retrospective chart review of a patient who presented with aneurysmal subarachnoid hemorrhage and developed clinical vasospasm twice over a period of 2 weeks. Sustained intravenous milrinone infusion was used in association with norepinephrine infusion during this period. The patient developed R-on-T triggered torsades de pointes and cardiogenic shock requiring resuscitation. Follow-up echocardiogram showed decreased ejection fraction from 64% to 43% consistent with cardiac remodeling. Systemic complications such as cardiotoxicity and arrhythmias with the use of intravenous milrinone can be seen particularly when used in combination with catecholamines.

CONCLUSIONS

With increased combined milrinone and catecholamine use for the treatment of cerebral vasospasm, physicians should be aware of the potential cardiac complications of these agents. Close monitoring with daily electrocardiograms may be helpful to detect changes that suggest cardiotoxicity. If changes are noted, an echocardiogram and cardiology consultation may be warranted.

Early detection of nonneurologic organ failure in patients with severe traumatic brain injury: Multiple organ dysfunction score or sequential organ failure assessment?

Objective:

The aim of this study is to compare the discriminant function of multiple organ dysfunction score (MODS) and sequential organ failure assessment (SOFA) components in predicting the Intensive Care Unit (ICU) mortality and neurologic outcome.

Materials and Methods:

A descriptive–analytic study was conducted at a level I trauma center. Data were collected from patients with severe traumatic brain injury admitted to the neurosurgical ICU. Basic demographic data, SOFA and MOD scores were recorded daily for all patients. Odd's ratios (ORs) were calculated to determine the relationship of each component score to mortality, and area under receiver operating characteristic (AUROC) curve was used to compare the discriminative ability of two tools with respect to ICU mortality.

Results:

The most common organ failure observed was respiratory detected by SOFA of 26% and MODS of 13%, and the second common was cardiovascular detected by SOFA of 18% and MODS of 13%. No hepatic or renal failure occurred, and coagulation failure reported as 2.5% by SOFA and MODS. Cardiovascular failure defined by both tools had a correlation to ICU mortality and it was more significant for SOFA (OR = 6.9, CI = 3.6–13.3, P < 0.05 for SOFA; OR = 5, CI = 3–8.3, P < 0.05 for MODS; AUROC = 0.82 for SOFA; AUROC = 0.73 for MODS). The relationship of cardiovascular failure to dichotomized neurologic outcome was not significant statistically. ICU mortality was not associated with respiratory or coagulation failure.

Conclusion:

Cardiovascular failure defined by either tool significantly related to ICU mortality. Compared to MODS, SOFA-defined cardiovascular failure was a stronger predictor of death. ICU mortality was not affected by respiratory or coagulation failures.

Differing effects when using phenylephrine and norepinephrine to augment cerebral blood flow after traumatic brain injury in the immature brain

Low cerebral blood flow (CBF) states have been demonstrated in children early after traumatic brain injury (TBI), and have been correlated with poorer outcomes. Cerebral perfusion pressure (CPP) support following severe TBI is commonly implemented to correct cerebral hypoperfusion, but the efficacy of various vasopressors has not been determined. Sixteen 4-week-old female swine underwent nonimpact inertial brain injury in the sagittal plane. Intraparenchymal monitors were placed to measure intracranial pressure (ICP), CBF, brain tissue oxygen tension (PbtO2), and cerebral microdialysis 30 min to 6 h post-injury. One hour after injury, animals were randomized to receive either phenylephrine (PE) or norepinephrine (NE) infusions titrated to a CPP>70 mm Hg for 5 h. Animals were euthanized 6 h post-TBI, and brains were fixed and stained to assess regions of cell and axonal injury. After initiation of CPP augmentation with NE or PE infusions, there were no differences in ICP between the groups or over time. Animals receiving NE had higher PbtO2 than those receiving PE (29.6±10.2 vs. 19.6±6.4 torr at 6 h post-injury, p<0.05). CBF increased similarly in both the NE and PE groups. CPP support with PE resulted in a greater reduction in metabolic crisis than with NE (lactate/pyruvate ratio 16.7±2.4 vs. 42.7±10.2 at 6 h post-injury, p<0.05). Augmentation of CPP to 70 mm Hg with PE resulted in significantly smaller cell injury volumes at 6 h post-injury than CPP support with NE (0.4% vs. 1.4%, p<0.05). Despite similar increases in CBF, CPP support with NE resulted in greater brain tissue oxygenation and hypoxic-ischemic injury than CPP support with PE. Future clinical studies comparing the effectiveness of various vasopressors for CPP support are warranted.

Norepinephrine as a potential aggravator of symptomatic cerebral vasospasm: two cases and argument for milrinone therapy

Background. During hypertensive therapy for post-subarachnoid hemorrhage (SAH) symptomatic vasospasm, norepinephrine is commonly used to reach target blood pressures. Concerns over aggravation of vasospasm with norepinephrine exist. Objective. To describe norepinephrine temporally related deterioration in neurological examination of two post-SAH patients in vasospasm. Methods. We retrospectively reviewed two charts of patients with delayed cerebral ischemia (DCI) post-SAH who deteriorated with norepinephrine infusions. Results. We identified two patients with DCI post-SAH who deteriorated during hypertensive therapy with norepinephrine. The first, a 43-year-old male presented to hospital with DCI, failed MABP directed therapy with rapid deterioration in exam with high dose norepinephrine and MABP of 140–150 mm Hg. His exam improved on continuous milrinone and discontinuation of norepinephrine. The second, a 39-year-old female who developed DCI on postbleed day 8 responded to milrinone therapy upfront. During further deterioration and after angioplasty, norepinephrine was utilized to drive MABP to 130–140 mm Hg. Progressive deterioration in examination occurred after angioplasty as norepinephrine doses escalated. After discontinuation of norepinephrine and continuation of milrinone, function dramatically returned but not to baseline. Conclusions. The potential exists for worsening of DCI post-SAH with hypertensive therapy directed by norepinephrine. A potential role exists for vasodilation and inotropic directed therapy with milrinone in the setting of DCI post-SAH.

Brain perfusion and oxygenation

Maintenance of brain perfusion and oxygenation is of paramount importance to patient outcome with various types of brain injuries (traumatic, ischemic, and hemorrhagic). Historically, monitoring of intracranial pressure and cerebral perfusion pressure has been the mainstay of neuromonitoring techniques used at the critical care bedside to monitor brain perfusion and oxygenation. This article describes the bedside neuromonitoring techniques that have emerged for use with these patients in the critical care area. To give the reader an understanding of the functionality of these neuromonitoring techniques, the article first summarizes the physiology of brain perfusion and oxygenation.

Cerebral hemodynamic changes after wartime traumatic brain injury

Traumatic brain injury (TBI) is associated with the severest casualties from Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF). From October 1, 2008, the U.S. Army Medical Department initiated a transcranial Doppler (TCD) ultrasound service for TBI; included patients were retrospectively evaluated for TCD-determined incidence of post-traumatic cerebral vasospasm and intracranial hypertension after wartime TBI. Ninety patients were investigated with daily TCD studies and a comprehensive TCD protocol, and published diagnostic criteria for vasospasm and increased intracranial pressure (ICP) were applied. TCD signs of mild, moderate, and severe vasospasms were observed in 37%, 22%, and 12% of patients, respectively. TCD signs of intracranial hypertension were recorded in 62.2%; 5 patients (4.5%) underwent transluminal angioplasty for post-traumatic clinical vasospasm treatment, and 16 (14.4%) had cranioplasty. These findings demonstrate that cerebral arterial spasm and intracranial hypertension are frequent and significant complications of combat TBI; therefore, daily TCD monitoring is recommended for their recognition and subsequent management.

Management of delayed cerebral ischemia after subarachnoid hemorrhage

PURPOSE OF REVIEW

The purpose of this article is to describe the modern management of delayed cerebral ischemia (DCI) in patients with aneurysmal subarachnoid hemorrhage (SAH). SAH causes an inflammatory reaction to blood products in the basal cisterns of the brain, which may produce cerebral ischemia and strokes through progressive narrowing of the cerebral artery lumen. This process, known as cerebral vasospasm, is the most common cause of DCI after SAH. Untreated DCI may result in strokes, which account for a significant portion of the death and long-term disability after SAH.

RECENT FINDINGS

A number of publications, including two recent consensus statements, have clarified many best practices for defining, diagnosing, monitoring, preventing, and treating DCI. DCI is best defined as new onset of focal or global neurologic deficits or strokes not attributable to another cause. In addition to the clinical examination, radiographic studies such as transcranial Doppler ultrasonography, CT angiography, and CT perfusion may have a role in determining which patients are at high risk for developing DCI. The mainstay of prevention and treatment of DCI is maintenance of euvolemia, which can be a difficult therapeutic target to measure. Hemodynamic augmentation with induced hypertension with or without inotropic support has become the first-line treatment of DCI. The ideal method of measuring hemodynamic values and volume status in patients with DCI remains elusive. In patients who do not adequately respond to or cannot tolerate hemodynamic augmentation, endovascular therapy (intraarterial vasodilators and balloon angioplasty) is a complementary strategy. Optimal triggers for escalation and de-escalation of therapies for DCI have not been well defined.

SUMMARY

Recent guidelines and consensus statements have clarified many aspects of prevention, monitoring, and treatment of DCI after SAH. Controversies continue regarding the optimal methods for measurement of volume status, the role of invasive neuromonitoring, and the targets for hemodynamic augmentation therapy.

Unilateral posterior reversible encephalopathy syndrome with hypertensive therapy of contralateral vasospasm: case report

BACKGROUND AND IMPORTANCE

Hemodynamic treatment of subarachnoid hemorrhage-induced vasospasm is associated with a number of systemic and cerebral risks. However, hypertensive encephalopathy has rarely been reported in the setting of induced hypertension. Recognition of this complication is nonetheless critical because failure to lower blood pressure may lead to worsening of deficits and even permanent injury.

CLINICAL PRESENTATION

This report details a case of unilateral hypertensive encephalopathy (also referred to as posterior reversible encephalopathy syndrome [PRES]) in a subarachnoid hemorrhage patient who was being treated with induced hypertension for symptomatic vasospasm affecting the contralateral hemisphere. This patient developed right hemispheric deficits associated with angiographic vasospasm of the right middle cerebral artery, which responded to induced hypertension. However, within 24 hours of raising blood pressure, the patient deteriorated with new left hemispheric deficits that paradoxically worsened when blood pressure was raised further in response. Computed tomography imaging was suspicious for evolving infarction in the left hemisphere, but on reevaluation, concern for PRES was raised. Magnetic resonance imaging confirmed left hemispheric PRES, and a dramatic neurological improvement occurred almost immediately after lowering blood pressure. Repeat CT showed resolution of the left hemispheric edema.

CONCLUSION

This is the first reported case of unilateral PRES in the setting of subarachnoid hemorrhage. It likely occurred because right-sided vasospasm attenuated ipsilateral distal perfusion pressures, leaving the left hemisphere vulnerable to the consequences of induced hypertension. Hypertensive encephalopathy should be considered in patients with unilateral or asymmetric vasospasm when neurological worsening occurs in the contralateral hemisphere during induced hypertension and/or the patient paradoxically worsens despite raising blood pressure.

Hemodynamic stability after intraarterial injection of verapamil for cerebral vasospasm

BACKGROUND

Vasospasm after subarachnoid hemorrhage is a common and potentially life-threatening complication. Treatment of vasospasm may include intraarterial (IA) injections of verapamil into the cerebral vasculature. Clinical experience suggests that the average patient experiences an acute reduction in systemic blood pressure after IA verapamil. Our study objective was to (1) identify the effects of IA injection of verapamil on mean arterial blood pressure (MAP) and heart rate (HR) in patients with cerebral vasospasm and (2) determine the effect of verapamil dose on change in MAP and HR. We hypothesized that (1) selective IA injection of verapamil for treatment of cerebral vasospasm is associated with a reduction in MAP and an increase in HR and (2) the change in MAP and HR are linearly related to the dose of verapamil administered.

METHODS

We prospectively studied subjects with vasospasm scheduled for cerebral angiography with possible IA injection of verapamil. All subjects were given a general anesthetic. Invasive arterial blood pressure and HR were monitored continuously and recorded at 10-second intervals throughout the procedure. We identified the lowest MAP and highest HR before and after verapamil injection. The association between IA verapamil and change in MAP and HR was determined using repeated-measures multivariate regression analysis, adjusting for potential confounding factors (weight, preoperative vasopressor use, and preinjection MAP). Data are reported as adjusted coefficients and 95% confidence intervals (CI).

RESULTS

We included 20 subjects who underwent a total of 46 injections of IA verapamil. On the basis of our multivariate model, on average, each 5 mg of IA verapamil was associated with a 3.5 mm Hg reduction in MAP (95% CI -5.0 to -2.0, P < 0.001). HR was not significantly altered by IA verapamil on both unadjusted and adjusted analyses (nonsignificant increase of 0.4 beats per minute for each 5 mg of IA verapamil, 95% CI -1.6 to 2.4, P = 0.70).

CONCLUSIONS

Under general anesthesia, injection of IA verapamil into cerebral arteries reduces MAP but does not change HR in the average patient. Further research is required to determine the clinical significance of these results.

Management of aneurysmal subarachnoid hemorrhage

OBJECTIVE

Acute aneurysmal subarachnoid hemorrhage (SAH) is a complex multifaceted disorder that plays out over days to weeks. Many patients with SAH are seriously ill and require a prolonged intensive care unit stay. Cardiopulmonary complications are common. The management of patients with SAH focuses on the anticipation, prevention, and management of these secondary complications.

DATA SOURCES

Source data were obtained from a PubMed search of the medical literature.

DATA SYNTHESIS AND CONCLUSION

The rupture of an intracranial aneurysm is a sudden devastating event with immediate neurologic and cardiac consequences that require stabilization to allow for early diagnostic angiography. Early complications include rebleeding, hydrocephalus, and seizures. Early repair of the aneurysm (within 1-3 days) should take place by surgical or endovascular means. During the first 1-2 weeks after hemorrhage, patients are at risk of delayed ischemic deficits due to vasospasm, autoregulatory failure, and intravascular volume contraction. Delayed ischemia is treated with combinations of volume expansion, induced hypertension, augmentation of cardiac output, angioplasty, and intra-arterial vasodilators. SAH is a complex disease with a prolonged course that can be particularly challenging and rewarding to the intensivist.

Resuscitation of patients after traumatic brain injury

Traumatic brain injury (TBI) is the commonest worldwide cause of death and disability in people under 45 years of age. Following an injury of this nature, physiological derangements, both systemic and within the brain, rapidly progress and have a deleterious effect on outcome. There is a lack of brain specific treatments that significantly improve outcome and management must therefore be best care of appropriate physiology, along the familiar ABC lines. There are international guidelines that describe targets to be achieved. Methods to do this plus the rationale for doing so are discussed in this article.