Cardiac performance indices during hypervolemic therapy for cerebral vasospasm

Hemodynamic Management in the Prevention and Treatment of Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

One of the most serious complications after subarachnoid hemorrhage (SAH) is delayed cerebral ischemia, the cause of which is multifactorial. Delayed cerebral ischemia considerably worsens neurological outcome and increases the risk of death. The targets of hemodynamic management of SAH have widely changed over the past 30 years. Hypovolemia and hypotension were favored prior to the era of early aneurysmal surgery but were subsequently replaced by the use of hypervolemia and hypertension. More recently, the concept of goal-directed therapy targeting euvolemia, with or without hypertension, is gaining preference. Despite the evolving concepts and the vast literature, fundamental questions related to hemodynamic optimization and its effects on cerebral perfusion and patient outcomes remain unanswered. In this review, we explain the rationale underlying the approaches to hemodynamic management and provide guidance on contemporary strategies related to fluid administration and blood pressure and cardiac output manipulation in the management of SAH.

CVP and PAoP Measurements Are Discordant During Fluid Therapy After Traumatic Brain Injury

The objective of the study was to compare measurements of central venous pressure (CVP) and pulmonary artery occlusion pressures (PAoP) as estimates of intravascular volume during the first 96 hours of fluid therapy after traumatic brain injury (TBI). One thousand five hundred ten simultaneous CVP and PAoP measurements from 31 patients entered into the National Acute Brain Injury Study: Hypothermia (NABISH:H) protocol were retrospectively compared. The effect of fluid administration and body temperature upon the paired measurements was statistically assessed. Agreement between CVP and PAoP values was poor. The CVP and PAoP were equal in only 11% of paired values. The CVP was always higher than PAoP in 1 patient, whereas PAoP always exceeded the CVP in 5 others. In 74% of the pairs, the PAoP was higher than the CVP, whereas in 15%, CVP was greater than PAoP. For any CVP measurement, the PAoP was either 3 mm Hg above or below the CVP in 67% of the pairs and at least 5 mm Hg above or below the CVP in 21% of the pairs. In 21 (68%) patients, PAoP was= 5 mm Hg above CVP in more than 4 readings, a clinically important difference. Discordance was not attributed to the fluid administered or to the temperature protocol. Neurological outcome appears affected by the volume of fluid administration. However, during initial therapy, estimates of intravascular volume provided by the CVP and PAoP are discordant. Although documented in other clinical conditions, the disparity noted here after TBI has not been previously reported. Assessment of intravascular volume to avoid hypovolemia should utilize other measurement techniques.

Effects of hypervolemia and hypertension on regional cerebral blood flow, intracranial pressure, and brain tissue oxygenation after subarachnoid hemorrhage

OBJECTIVE

Hypertensive, hypervolemic, hemodilution therapy (triple-H therapy) is a generally accepted treatment for cerebral vasospasm after subarachnoid hemorrhage. However, the particular role of the three components of triple-H therapy remains controversial. The aim of the study was to investigate the influence of the three arms of triple-H therapy on regional cerebral blood flow and brain tissue oxygenation.

DESIGN

Animal research and clinical intervention study.

SETTING

Surgical intensive care unit of a university hospital.

SUBJECTS AND PATIENTS

Experiments were carried out in five healthy pigs, followed by a clinical investigation of ten patients with subarachnoid hemorrhage.

INTERVENTIONS

First, we investigated the effect of the three components of triple-H therapy under physiologic conditions in an experimental pig model. In the next step we applied the same study protocol to patients following aneurysmal subarachnoid hemorrhage. Mean arterial pressure, intracranial pressure, cerebral perfusion pressure, cardiac output, regional cerebral blood flow, and brain tissue oxygenation were continuously recorded. Intrathoracic blood volume and central venous pressure were measured intermittently. Vasopressors and/or colloids and crystalloids were administered to stepwise establish the three components of triple-H therapy.

MEASUREMENTS AND MAIN RESULTS

In the animals, neither induced hypertension nor hypervolemia had an effect on intracranial pressure, brain tissue oxygenation, or regional cerebral blood flow. In the patient population, induction of hypertension (mean arterial pressure 143 +/- 10 mm Hg) resulted in a significant (p < .05) increase of regional cerebral blood flow and brain tissue oxygenation at all observation time points. In contrast, hypervolemia/hemodilution (intrathoracic blood volume index 1123 +/- 152 mL/m) induced only a slight increase of regional cerebral blood flow while brain tissue oxygenation did not improve. Finally, triple-H therapy failed to improve regional cerebral blood flow more than hypertension alone and was characterized by the drawback that the hypervolemia/hemodilution component reversed the effect of induced hypertension on brain tissue oxygenation.

CONCLUSIONS

Vasopressor-induced elevation of mean arterial pressure caused a significant increase of regional cerebral blood flow and brain tissue oxygenation in all patients with subarachnoid hemorrhage. Volume expansion resulted in a slight effect on regional cerebral blood flow only but reversed the effect on brain tissue oxygenation. In view of the questionable benefit of hypervolemia on regional cerebral blood flow and the negative consequences on brain tissue oxygenation together with the increased risk of complications, hypervolemic therapy as a part of triple-H therapy should be applied with utmost caution.

A Comparative Coagulopathic Study for Treatment of Vasospasm by Using Low- and High-molecular Weight Hydroxyethyl Starches

OBJECTIVE

High-molecular-weight hydroxyethyl starch (HES) compromises blood coagulation more than does low-molecular-weight HES. We compared the effects of low- and high-molecular-weight HES for the treatment of vasospasm and investigated the dose relationship with each other.

METHODS

Retrospectively, in a series of consecutive 102 patients with subarachnoid hemorrhage (SAH), 35 patients developed clinical symptoms of vasospasm of these fourteen patients were treated with low-molecular-weight HES for volume expansion while the other 21 received high-molecular-weight HES as continuous intravenous infusion. Prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen level, and platelet count were all measured prior to initiation, during treatment and after termination of therapy for symptomatic vasospasm. The total dose of HES ranged from 5 L to 14 L and median infusion duration was 10 days.

RESULTS

A more pronounced PTT prolongation was observed in high-molecular-weight HES group compared with low-molecular-weight HES group. No other coagulation parameters were altered. Dosage (=duration) shows a positive correlation with PTT. Clinically, significant bleeding episodes were noted in four patients who received high-molecular-weight HES.

CONCLUSION

Coagulopathy was developed in direct proportion to molecular weight of starch and dosages. We propose the extreme caution in the administration of HES solution for the vasospasm treatment.

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

PURPOSE OF REVIEW

The intent of this manuscript is to summarize the pathophysiologic basis for hemodynamic manipulation in subarachnoid hemorrhage and traumatic brain injury, highlight the most recent literature and present expert opinion on indications and use.

RECENT FINDINGS

Hemodynamic augmentation with vasopressors and inotropes along with hypervolemia are the mainstay of treatment of vasospasm due to subarachnoid hemorrhage. Considerable variation continues to exist regarding fluid management and the use of vasopressors and inotropes. Blood pressure augmentation, volume expansion and cardiac contractility enhancement improve cerebral blood flow in ischemic areas, ameliorate vasospasm and improve clinical condition. In patients suffering from severe traumatic brain injury, while every attempt is made to control intracranial hypertension, cerebral perfusion-directed therapy with fluids and vasopressors is also used to keep cerebral perfusion pressure above 60-70 mmHg. Yet, recent observations suggest that posttraumatic mitochondrial dysfunction has been proposed as an alternative explanation for lower cerebral blood flow after acute trauma.

SUMMARY

Hemodynamic manipulation is routinely used in the management of patients with acute vasospasm following subarachnoid hemorrhage and severe head injury. The rationale is to improve blood flow to the injured brain and prevent secondary ischemia.

Dobutamine versus milrinone after subarachnoid hemorrhage

OBJECTIVE

Neurogenic stunned myocardium is a well-recognized complication of subarachnoid hemorrhage. Dobutamine and milrinone are both used for neurogenic stunned myocardium, but there are few data comparing them after subarachnoid hemorrhage.

METHODS

We compared the physiological dose response of dobutamine and milrinone in patients with subarachnoid hemorrhage requiring a pulmonary artery catheter. We located 11 patients who received either inotrope. Physiological data were fitted to a mixed model accounting for drug, dose, and between-patient variation.

RESULTS

There were 11 patients who had 152 pulmonary artery catheter measurements. Two received both inotropes (but not within 4 h of each other), 2 only milrinone, and 7 only dobutamine. The groups had similar clinical and physiological characteristics. After adjustment for vasopressin, milrinone was significantly more potent in increasing cardiac output (P <0.0001) and stroke volume (P=0.03), while decreasing vascular resistance (P <0.0001) and systolic blood pressure (P=0.008), than dobutamine.

CONCLUSION

These data suggest that milrinone and dobutamine should be used in different clinical situations. Milrinone may be more effective in patients with severely depressed systolic function but who have at least normal vascular resistance and blood pressure and in whom raising cardiac output is the primary goal. Dobutamine may be superior when vascular resistance or blood pressure is low.

Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage: An Overview of Pharmacologic Management

Cerebral vasospasm remains one of the leading causes of mortality in patients who experience a subarachnoid hemorrhage but survive the initial 24 hours. Vasospasm generally occurs 3-4 days after the initial subarachnoid hemorrhage and peaks at 5-7 days. The pathophysiology of vasospasm is poorly understood, which directly contributes to the inconsistency of management and creates a formidable challenge in clinical practice. Traditionally, hemodilution, hypervolemia, and induced hypertension (so-called triple H therapy); calcium channel blockers; and endovascular therapy have been used as either prophylactic therapy or treatment. However, management of vasospasm varies among physicians and institutions mainly because of a lack of large clinical trials and inconsistent results. Practice has been based primarily on case reports and the preference of each practitioner. Several experimental therapies have been explored; however, large, prospective, randomized controlled trials are needed to elucidate the role of these therapies.

Reduction of pulmonary edema after SAH with a pulmonary artery catheter-guided hemodynamic management protocol

INTRODUCTION

The frequency of pulmonary edema, which occurs with high frequency following subarachnoid hemorrhage (SAH), can be worsened by hypervolemic, hypertensive, hemodilution therapy for vasospasm. This study compares the complication rates for patients with SAH before and after institution of a pulmonary artery catheter-guided hemodynamic management protocol.

METHODS

Complication and outcome data were prospectively collected on 453 patients with spontaneous SAH. The patients were divided into groups treated from July 1998 through January 2000 (n = 174) and from February 2002 through June 2002 (n = 279). In group I, treatment consisted of hypervolemia (central venous pressures: >8 mmHg) and hypertension (mean arterial pressure: 110-130 mmHg). In group II, normovolemia was the goal, defined using a pulmonary artery catheter (wedge pressure: 10-14 mmHg). Cardiac output was enhanced (index: >4.5 L/minute/m2), and blood pressure elevations were moderated (mean pressure: >100 mmHg).

RESULTS

The average age, comorbidity, hemorrhage severity, and incidence of vasospasm were almost identical between the two groups. Statistically significant reductions were noted in patients in group II for two types of complications as well as for mortality. The rate of pulmonary edema (from 14 to 6%) and the rate of sepsis (from 14 to 6%) were both decreased (p <or= 0.03). Mortality decreased from 34 to 29% (p = 0.04). Other complications, such as myocardial infarction, were not affected.

CONCLUSIONS

These data show that a significant reduction in the frequency of pulmonary edema after SAH can be attained using a pulmonary artery catheter-guided hemodynamic management protocol.

Relative importance of hypertension compared with hypervolemia for increasing cerebral oxygenation in patients with cerebral vasospasm after subarachnoid hemorrhage

Object. Hypervolemia and hypertension therapy is routinely used for prophylaxis and treatment of symptomatic cerebral vasospasm at many institutions. Nevertheless, there is an ongoing debate about the preferred modality (hypervolemia, hypertension, or both), the degree of therapy (moderate or aggressive), and the risk or benefit of hypervolemia, moderate hypertension, and aggressive hypertension in patients following subarachnoid hemorrhage.

Methods. Monitoring data and patient charts for 45 patients were retrospectively searched to identify periods of hypervolemia, moderate hypertension, or aggressive hypertension. Measurements of central venous pressure, fluid input, urine output, arterial blood pressure, intracranial pressure, and oxygen partial pressure (PO2) in the brain tissue were extracted from periods ranging from 1 hour to 24 hours. For these periods, the change in brain tissue PO2 and the incidence of complications were analyzed.

During the 55 periods of moderate hypertension, an increase in brain tissue PO2 was found in 50 cases (90%), with complications occurring in three patients (8%). During the 25 periods of hypervolemia, an increase in brain oxygenation was found during three intervals (12%), with complications occurring in nine patients (53%). During the 10 periods of aggressive hypervolemic hypertension, an increase in brain oxygenation was found during six of the intervals (60%), with complications in five patients (50%).

Conclusions. When hypervolemia treatment is applied as in this study, it may be associated with increased risks. Note, however, that further studies are needed to determine the role of this therapeutic modality in the care of patients with cerebral vasospasm. In poor-grade patients, moderate hypertension (cerebral perfusion pressure 80–120 mm Hg) in a normovolemic, hemodiluted patient is an effective method of improving cerebral oxygenation and is associated with a lower complication rate compared with hypervolemia or aggressive hypertension therapy.

Therapeutic hypertension: principles and methods

The aspects of cardiovascular physiology important for the safe and effective implementation and titration of hypertensive therapy among neurosurgical patients with neurological or neurosurgical illness/injury are reviewed. Therapeutic hypertension may be an appropriate treatment for some neurological or neurosurgical conditions, e.g., vasospasm or support of cerebral perfusion pressure. Initiation and maintenance of hypertension should be done safely to avoid complications and/or undesired side effects. Accurate measurement of the arterial and central vascular pressures, the limitations of those methods, and alternative estimates of intravascular volume are reviewed. Hypertensive therapy is accomplished by modifying cardiac output and systemic vascular resistance, the principal physiological determinants of blood pressure. The goals of hypertensive therapy can be achieved by proper evaluation and manipulation of the four components of cardiac output, preload, afterload, heart rate and contractility. Measurement or calculation of estimates of these parameters is important in the selection of proper medications or supplemental fluid administration.

Jugular bulb oximetry for prediction of vasospasm following subarachnoid hemorrhage

BACKGROUND

Cerebral vasospasm adversely impacts the outcome of those suffering aneurysmal subarachnoid hemorrhage (SAH). Prediction of vasospasm could improve outcomes. We hypothesized that preclinical vasospasm would be heralded by an increase in cerebral oxygen extractions (AVDO2) which could be detected by jugular bulb oximetry. A pilot study was conducted to address this hypothesis.

METHODS

Fourteen consenting patients with aneurysmal SAH, undergoing early surgery, were entered into the study. Four patients were withdrawn from the study secondary to failure of catheters or religious belief. At the time of craniotomy, a jugular bulb catheter was placed. Post-operatively, arterial and jugular bulb blood samples were taken every 12 hours to calculate AVDO2. As this was an observational study, no change in management occurred based on measurements.

RESULTS

Four of 10 patients had clinical vasospasm. These patients had a significant rise in AVDO2 approximately one day prior to the onset of neurologic deficits (P<0.001). Symptoms resolved along with a significant improvement in AVDO2 on instituting hypertensive, hemo-dilutional, and hypervolemic therapy in these patients. The six patients who did not exhibit clinical vasospasm did not demonstrate significant rise in AVDO2.

CONCLUSIONS

Jugular bulb oximetry is simple and cost effective. Increases in AVDO2 using this technique were predictive of clinically evident vasospasm in the subsequent hours to days. This investigation supports a larger study to assess the utility of jugular bulb oximetry in predicting vasospasm in aneurysmal SAH.

Increases in Cardiac Output Can Reverse Flow Deficits from Vasospasm Independent of Blood Pressure: A Study Using Xenon Computed Tomographic Measurement of Cerebral Blood Flow

INTRODUCTION

Vasospasm after subarachnoid hemorrhage remains a management challenge. The accepted treatment involves hypertensive, hypervolemic, hemodilution therapy. However, there is variation in the application of this treatment. Most authors increase mean arterial pressure (MAP), which can be associated with significant morbidity. Others increase cardiac output (CO). In this study, we examined the relationship between volume status, CO, and MAP and cerebral blood flow (CBF) in the setting of vasospasm.

METHODS

A xenon blood flow tomography-based system was used to quantitate CBF. Sixteen patients with vasospasm after subarachnoid hemorrhage were treated with hypervolemia, phenylephrine to increase MAP, or dobutamine to increase CO. Direct CBF measurements were obtained before and after treatment. A strength of this study is that only one variable (central venous pressure, MAP, or CO) was manipulated in each patient, and the effect of this change was measured immediately.

RESULTS

With phenylephrine, mean MAP increased from 102.4 to 132.1 mm Hg. In regions of diminished CBF due to vasospasm, mean CBF increased from 19.2 to 33.7 ml/100 g/min. Similarly, dobutamine increased the cardiac index from a mean of 4.1 to 6.0 L/min/m2 and slightly decreased MAP. CBF increased from a mean of 24.8 to 35.4 ml/100 g/min. Both were statistically significant changes. With hypervolemia, the average central venous pressure increased from a mean of 5.4 to 7.3 cm H2O; no changes in mean CBF were noted.

CONCLUSION

This article reports the first human study that shows with direct measurements the independent influence of CO in the setting of vasospasm. Increases in CO without changes in MAP can elevate CBF. This finding has immediate clinical application because CO manipulation is much safer than increasing MAP. Because both interventions were equally efficacious, our protocol has been changed to augment CO as a first measure. Induced hypertension is reserved for patients in whom this initial treatment fails.

Systematic review of the prevention of delayed ischemic neurological deficits with hypertension, hypervolemia, and hemodilution therapy following subarachnoid hemorrhage

OBJECT

There is uncertainty about the efficacy of hypertension, hypervolemia, and hemodilution (triple-H) therapy in reducing the occurrence of delayed ischemic neurological deficits (DINDs) and death after subarachnoid hemorrhage. The authors therefore conducted a systematic review to evaluate the efficacy of triple-H prevention in decreasing the rate of clinical vasospasm, DINDs, and death.

METHODS

The authors systematically reviewed studies identified based on a MEDLINE, EMBASE, and COCHRANE Register search of articles published between 1966 and 2001, and reference lists of identified articles. An independent assessment of each study's methodological quality, population, intervention, and outcomes (rates of symptomatic vasospasm, DINDs, and death) was performed. Summary relative risk estimates were calculated for the main outcomes using fixed- or random-effect models, as appropriate. Only four prospective, comparative studies with a total of 488 patients were identified. The median internal validity score was 0.5 (range 0-2); the median external validity score was 3 (range 2-6). Compared with no prevention, triple-H therapy was associated with a reduced risk of symptomatic vasospasm (relative risk [RR] 0.45, 95% confidence interval [CI] 0.32-0.65), but not DIND (RR 0.54, 95% CI 0.2-1.49). The risk of death was higher (RR 0.68, 95% CI 0.53-0.87). Sensitivity analyses including only randomized, controlled trials showed no evidence of statistically significant results for these major end points.

CONCLUSIONS

The paucity of information and important limitations in the design of the studies analyzed preclude evaluation of the efficacy of triple-H prevention and formulation of any recommendations regarding its use for the prevention of cerebral vasospasm.

Ultra-early surgery for aneurysmal subarachnoid hemorrhage: outcomes for a consecutive series of 391 patients not selected by grade or age

OBJECT

This study was undertaken to determine the outcomes in an unselected group of patients treated with semiurgent surgical clipping of aneurysms following subarachnoid hemorrhage (SAH).

METHODS

A clinical management outcome audit was conducted to determine outcomes in a group of 391 consecutive patients who were treated with a consistent policy of ultra-early surgery (all patients treated within 24 hours after SAH and 85% of them within 12 hours). All neurological grades were included, with 45% of patients having poor grades (World Federation of Neurosurgical Societies [WFNS] Grades IV and V). Patients were not selected on the basis of age; their ages ranged between 15 and 93 years and 19% were older than 70 years. The series included aneurysms located in both anterior and posterior circulations. Eighty-eight percent of all patients underwent surgery and only 2.5% of the series were selectively withdrawn (by family request) from the prescribed surgical treatment. In patients with good grades (WFNS Grades I-III) the 3-month postoperative outcomes were independence (good outcome) in 84% of cases, dependence (poor outcome) in 8% of cases, and death in 9%. In patients with poor grades the outcomes were independence in 40% of cases, dependence in 15% of cases, and death in 45%. There was a 12% rate of rebleeding with all cases of rebleeding occurring within the first 12 hours after SAH; however, outcomes of independence were achieved in 46% of cases in which rebleeding occurred (43% mortality rate). Rebleeding was more common in patients with poor grades (20% experienced rebleeding, whereas only 5% of patients with good grades experienced rebleeding).

CONCLUSIONS

The major risk of rebleeding after SAH is present within the first 6 to 12 hours. This risk of ultra-early rebleeding is highest for patients with poor grades. Securing ruptured aneurysms by surgery or coil placement on an emergency basis for all patients with SAH has a strong rational argument.

Current concepts in neurocritical care

The current concepts in neurocritical care including advancement in therapeutic interventions and monitoring modalities are covered for four entities: stroke, subarachnoid hemorrhage, traumatic brain injury and spinal cord injury. Although therapies were mainly supportive in the past, acute ischemic stroke may now be treated with tissue plasminogen activator if inclusion and exclusion criteria are met. The management of subarachnoid hemorrhage including cerebral vasospasm is discussed in detail. Traumatic brain injury and spinal cord injury with prevention of secondary injury to limit further sequelae are also covered. Medical complications which increase morbidity and mortality are also presented.

Contemporary management of subarachnoid hemorrhage and vasospasm: the UIC experience

BACKGROUND

Cerebral vasospasm is a well-known and serious complication of aneurysmal subarachnoid hemorrhage. The means of monitoring and treatment of vasospasm have been widely studied. Each neurosurgical center develops a protocol based on their experience, availability of equipment and personnel, and cost, so as to keep morbidity and mortality rates as low as possible for their patients with vasospasm.

METHODS

At the University of Illinois at Chicago, we have developed algorithms for the diagnosis and management of cerebral vasospasm based on the experience of the senior authors over the past 25 years. This paper describes in detail our approach to diagnosis and treatment of aneurysmal subarachnoid hemorrhage and vasospasm. Our discussion is highlighted with data from a retrospective analysis of 324 aneurysm patients.

RESULTS

Over 3 years, 324 aneurysms were treated; 185 (57%) were clipped, 139 (43%) were coiled. The rate of vasospasm for the 324 patients was 27%. The rate of hydrocephalus was 32% for those patients who underwent clipping, and 29% for those coiled. The immediate outcomes for those who underwent clipping was excellent in 35%, good in 38%, poor in 15.5%, vegetative in 3%, and death in 8% of the patients. For those who underwent coiling the immediate outcome was excellent in 64%, good in 14.5%, vegetative in 2.5%, and death in 14.5% of the patients. These statistics include all Hunt and Hess grades. For those patients who underwent clipping, 51% were intact at 6 months follow-up, 15% had a permanent deficit, 10% had a focal cranial nerve deficit, and 2% had died from complications not directly related to the procedure. For those patients who had undergone coiling, 75% were intact at 6 months follow-up, 12.5% had a permanent deficit, and 12.5% had a cranial nerve deficit, with no deaths.

CONCLUSIONS

The morbidity and mortality of cerebral vasospasm is significant. A good outcome after aneurysmal subarachnoid hemorrhage is dependent upon careful patient management in the preoperative, perioperative, and postoperative periods. The timely work-up and aggressive treatment of neurological deterioration, whether or not it is because of vasospasm, is paramount.

Prophylactic hyperdynamic postoperative fluid therapy after aneurysmal subarachnoid hemorrhage: a clinical, prospective, randomized, controlled study

OBJECTIVE

To investigate the role of prophylactic hyperdynamic postoperative fluid therapy in preventing delayed ischemic neurological deficits attributable to cerebral vasospasm.

METHODS

We designed a prospected, randomized, controlled study and included 32 patients with subarachnoid hemorrhage. Sixteen patients received hypervolemic hypertensive hemodilution fluid therapy; the other 16 patients received normovolemic fluid therapy. All patients were monitored for at least 12 days, with clinical assessments, transcranial Doppler recordings, single-photon emission computed tomographic (SPECT) scanning, and routine computed tomographic scanning. For fluid balance monitoring, a number of blood samples were obtained on a daily basis and continuous central venous pressure and mean arterial blood pressure measurements were performed for both groups. All patients received intravenous nimodipine infusions between Day 1 and Day 12. End points of this study were clinical outcomes, clinically evident and transcranial Doppler sonography-evident vasospasm, SPECT findings, complications, and costs. Clinical examinations (using the Glasgow Outcome Scale) performed 1 year after discharge, together with neuropsychological assessments and SPECT scanning, were the basis for the evaluation of clinical outcomes.

RESULTS

No differences were observed between the two groups with respect to cerebral vasospasm (as observed clinically or on transcranial Doppler recordings). When regional cerebral blood flow was evaluated by means of SPECT analysis performed on Day 12 after subarachnoid hemorrhage, no differences were revealed. One-year clinical follow-up assessments (with the Glasgow Outcome Scale), including SPECT findings and neuropsychological function results, did not demonstrate any significant group differences. Costs were higher and complications were more frequent for the hyperdynamic therapy group.

CONCLUSION

Neither early nor late outcome measures revealed any significant differences between the two subarachnoid hemorrhage treatment models.

Effect of hypervolemic therapy on cerebral blood flow after subarachnoid hemorrhage : a randomized controlled trial

BACKGROUND AND PURPOSE

Cerebral blood flow (CBF) is reduced after subarachnoid hemorrhage (SAH), and symptomatic vasospasm is a major cause of morbidity and mortality. Volume expansion has been reported to increase CBF after SAH, but CBF values in hypervolemic (HV) and normovolemic (NV) subjects have never been directly compared.

METHODS

On the day after aneurysm clipping, we randomly assigned 82 patients to receive HV or NV fluid management until SAH day 14. In addition to 80 mL/h of isotonic crystalloid, 250 mL of 5% albumin solution was given every 2 hours to maintain normal (NV group, n=41) or elevated (HV group, n=41) cardiac filling pressures. CBF ((133)xenon clearance) was measured before randomization and approximately every 3 days thereafter (mean, 4.5 studies per patient).

RESULTS

HV patients received significantly more fluid and had higher pulmonary artery diastolic and central venous pressures than NV patients, but there was no effect on net fluid balance or on blood volume measured on the third postoperative day. There was no difference in mean global CBF during the treatment period between HV and NV patients (P=0.55, random-effects model). Symptomatic vasospasm occurred in 20% of patients in each group and was associated with reduced minimum regional CBF values (P=0.04). However, there was also no difference in minimum regional CBF between the 2 treatment groups.

CONCLUSIONS

HV therapy resulted in increased cardiac filling pressures and fluid intake but did not increase CBF or blood volume compared with NV therapy. Although careful fluid management to avoid hypovolemia may reduce the risk of delayed cerebral ischemia after SAH, prophylactic HV therapy is unlikely to confer an additional benefit.

Myocardial injury and left ventricular performance after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Electrocardiographic abnormalities and elevations of the creatine kinase myocardial isoenzyme (CK-MB) occur frequently after subarachnoid hemorrhage. In some patients, a reversible and presumably neurogenic form of left ventricular dysfunction is demonstrated by echocardiography. It is not known whether cardiac injury of this type adversely affects cardiovascular hemodynamic performance.

METHODS

We retrospectively studied 72 patients admitted to our neuro-ICU for aneurysmal subarachnoid hemorrhage over a 2.5-year period. We selected patients who met the following criteria: (1) CK-MB levels measured within 3 days of onset, (2) pulmonary artery catheter placed, (3) echocardiogram performed, and (4) no history of preexisting cardiac disease. Hemodynamic profiles were recorded on the day after surgery (n=67) or on the day of echocardiography (n=5) if surgery was not performed (mean, 3. 3+/-1.7 days after onset). The severity of cardiac injury was classified as none (peak CK-MB <1%, n=36), mild (peak CK-MB 1% to 2%, n=21), moderate (peak CK-MB >2%, n=6), or severe (abnormal left ventricular wall motion, n=9).

RESULTS

Abnormal left ventricular wall motion occurred exclusively in patients with peak CK-MB levels >2% (P<0.0001), poor neurological grade (P=0.002), and female sex (P=0.02). Left ventricular stroke volume index and stroke work index were elevated above the normal range in patients with peak CK-MB levels <1% and fell progressively as the severity of cardiac injury increased, with mean values for patients with abnormal wall motion below normal (both P<0.0001 by ANOVA). Cardiac index followed a similar trend, but the effect was less pronounced (P<0.0001). Using forward stepwise multiple logistic regression, we found that thick subarachnoid clot on the admission CT scan (odds ratio, 1.9; 95% confidence interval [95% CI], 1.0 to 3.4; P=0.04) and depressed cardiac index (odds ratio, 2.1; 95% CI, 1.0 to 4.1; P=0.04) were independent predictors of symptomatic vasospasm.

CONCLUSIONS

Myocardial enzyme release and echocardiographic wall motion abnormalities are associated with impaired left ventricular performance after subarachnoid hemorrhage. In severely affected patients, reduction of cardiac output from normally elevated levels may increase the risk of cerebral ischemia related to vasospasm.

Effect of 5% albumin solution on sodium balance and blood volume after subarachnoid hemorrhage

OBJECTIVE

Subarachnoid hemorrhage (SAH) predisposes patients to excessive natriuresis and volume contraction. We studied the effects of postoperative administration of 5% albumin solution on sodium balance and blood volume after SAH. We also sought to identify physiological variables that influence renal sodium excretion after SAH.

METHODS

Forty-three patients with acute SAH were randomly assigned to receive hypervolemia or normovolemia treatment for a period of 7 days after aneurysm clipping. In addition to a base line infusion of normal saline solution (80 ml/hr), 250 ml of 5% albumin solution was administered every 2 hours for central venous pressure (CVP) values of < or =8 mm Hg (hypervolemia group, n = 19) or < or =5 mm Hg (normovolemia group, n = 24).

RESULTS

Both groups demonstrated relative volume expansion in base line measurements. The hypervolemia group received significantly more total fluid, sodium, and 5% albumin solution than did the normovolemia group and had higher CVP values and serum albumin levels (all P < 0.02). Cumulative sodium balance was even in the hypervolemia group and persistently negative in the normovolemia group, because of sodium losses that occurred on Postoperative Days 2 and 3 (P = 0.03). In a multiple-regression analysis of all patients, 24-hour sodium balance correlated negatively with glomerular filtration rate (GFR) and positively with serum albumin levels, after correction for sodium intake (P < 0.0001). Hypervolemia therapy seemed to paradoxically lower GFR (P = 0.10) and had no effect on blood volume, which declined by 10% in both groups. Pulmonary edema requiring diuresis occurred in only one patient in the hypervolemia group.

CONCLUSION

Supplemental 5% albumin solution given to maintain CVP values of >8 mm Hg prevented sodium and fluid losses but did not have an impact on blood volume in our patients, who were hypervolemic in base line measurements. The natriuresis that occurs after SAH may be mediated in part by elevations of GFR. In addition to acting as a colloid volume expander, 5% albumin solution lowers the GFR and promotes renal sodium retention after SAH. These properties may limit the amount of total fluid required to maintain a given CVP value and hence may minimize the frequency of pulmonary edema.

Combined medical and surgical treatment after acute spinal cord injury: results of a prospective pilot study to assess the merits of aggressive medical resuscitation and blood pressure management

The optimal management of acute spinal cord injuries remains to be defined. The authors prospectively applied resuscitation principles of volume expansion and blood pressure maintenance to 77 patients who presented with acute neurological deficits as a result of spinal cord injuries occurring from C-1 through T-12 in an effort to maintain spinal cord blood flow and prevent secondary injury. According to the Intensive Care Unit protocol, all patients were managed by using Swan-Ganz and arterial blood pressure catheters and were treated with immobilization and fracture reduction as indicated. Intravenous fluids, colloid, and vasopressors were administered as necessary to maintain mean arterial blood pressure above 85 mm Hg. Surgery was performed for decompression and stabilization, and fusion in selected cases. Sixty-four patients have been followed at least 12 months postinjury by means of detailed neurological assessments and functional ability evaluations. Sixty percent of patients with complete cervical spinal cord injuries improved at least one Frankel or American Spinal Injury Association (ASIA) grade at the last follow-up review. Thirty percent regained the ability to walk and 20% had return of bladder function 1 year postinjury. Thirty-three percent of the patients with complete thoracic spinal cord injuries improved at least one Frankel or ASIA grade. Approximately 10% of the patients regained the ability to walk and had return of bladder function. As of the 12-month follow-up review, 92% of patients demonstrated clinical improvement after sustaining incomplete cervical spinal cord injuries compared to their initial neurological status. Ninety-two percent regained the ability to walk and 88% regained bladder function. Eighty-eight percent of patients with incomplete thoracic spinal cord injuries demonstrated significant improvements in neurological function 1 year postinjury. Eighty-eight percent were able to walk and 63% had return of bladder function. The authors conclude that the enhanced neurological outcome that was observed in patients after spinal cord injury in this study was in addition to, and/or distinct from, any potential benefit provided by surgery. Early and aggressive medical management (volume resuscitation and blood pressure augmentation) of patients with acute spinal cord injuries optimizes the potential for neurological recovery after sustaining trauma.

Combined medical and surgical treatment after acute spinal cord injury: results of a prospective pilot study to assess the merits of aggressive medical resuscitation and blood pressure management

The optimal management of acute spinal cord injuries remains to be defined. The authors prospectively applied resuscitation principles of volume expansion and blood pressure maintenance to 77 patients who presented with acute neurological deficits as a result of spinal cord injuries occurring from C-1 through T-12 in an effort to maintain spinal cord blood flow and prevent secondary injury. According to the Intensive Care Unit protocol, all patients were managed by using Swan-Ganz and arterial blood pressure catheters and were treated with immobilization and fracture reduction as indicated. Intravenous fluids, colloid, and vasopressors were administered as necessary to maintain mean arterial blood pressure above 85 mm Hg. Surgery was performed for decompression and stabilization, and fusion in selected cases. Sixty-four patients have been followed at least 12 months postinjury by means of detailed neurological assessments and functional ability evaluations. Sixty percent of patients with complete cervical spinal cord injuries improved at least one Frankel or American Spinal Injury Association (ASIA) grade at the last follow-up review. Thirty percent regained the ability to walk and 20% had return of bladder function 1 year postinjury. Thirty-three percent of the patients with complete thoracic spinal cord injuries improved at least one Frankel or ASIA grade. Approximately 10% of the patients regained the ability to walk and had return of bladder function. As of the 12-month follow-up review, 92% of patients demonstrated clinical improvement after sustaining incomplete cervical spinal cord injuries compared to their initial neurological status. Ninety-two percent regained the ability to walk and 88% regained bladder function. Eighty-eight percent of patients with incomplete thoracic spinal cord injuries demonstrated significant improvements in neurological function 1 year postinjury. Eighty-eight percent were able to walk and 63% had return of bladder function. The authors conclude that the enhanced neurological outcome that was observed in patients after spinal cord injury in this study was in addition to, and/or distinct from, any potential benefit provided by surgery. Early and aggressive medical management (volume resuscitation and blood pressure augmentation) of patients with acute spinal cord injuries optimizes the potential for neurological recovery after sustaining trauma.

Hypertensive, hypervolemic, hemodilutional therapy for aneurysmal subarachnoid hemorrhage. Is it efficacious? No

Many neurosurgeons routinely use hypertensive, hypervolemic, hemodilutional, or hyperdynamic therapy (HT) in some form to prevent or to treat vasospasm. Despite the widespread use of this therapy during the past 20 years, however, there are no randomized, prospective, controlled clinical studies demonstrating that HT improves the short- or long-term neurologic outcome or survival after subarachnoid hemorrhage. Guidelines need to be developed to standardize the clinical application of HT, and well-controlled, prospective, randomized clinical trials must be conducted before HT can become an accepted treatment for vasospasm.

Intra-aortic balloon pump counterpulsation in the management of concomitant cerebral vasospasm and cardiac failure after subarachnoid hemorrhage: technical case report

We report two patients who had symptomatic cerebral vasospasm and cardiac failure after aneurysmal subarachnoid hemorrhage and who were treated successfully with intra-aortic balloon pump counterpulsation therapy. Both patients developed congestive heart failure and pulmonary edema while receiving postoperative hypertensive, hypervolemic, hemodilutional (Triple-H) therapy for symptomatic cerebral vasospasm. Both cases of cardiac failure were refractory to maximum pressor and inotropic infusions. Intra-aortic balloon pump counterpulsation was used to optimize cardiac performance to allow continuation of Triple-H therapy and to maintain adequate cerebral perfusion in an attempt to decrease the risk of cerebral ischemic complications. Both patients have had good long-term outcomes. These two cases illustrate the potential usefulness of the intra-aortic balloon pump as an adjunct to Triple-H therapy in patients with symptomatic cerebral vasospasm and cardiac failure. To our knowledge, this report documents the first clinical application of this adjunctive therapy for vasospasm after aneurysmal subarachnoid hemorrhage.

[Enhancement of cardiac performance for prevention and treatment of delayed cerebral ischemia caused by vasospasm]

Following subarachnoid haemorrhage, delayed cerebral ischaemia from cerebral vasospasm remains the most important cause of mortality and morbidity in patients with surgically secured aneurysms. Therapy with haemodilution, hypertension and volume expansion has been recommended to prevent and treat delayed cerebral ischaemia in these patients on the basis of uncontrolled clinical series (level of evidence III to V, grade C recommendation). Despite the lack of controlled studies, the maintenance of a cardiac index > 3.5 L.min-1.m-2 and a systolic arterial pressure between 120 and 150 mmHg before clipping and 160 to 200 mmHg thereafter is recommended as a prophylactic or therapeutic measure for vasospasm. Close monitoring of neurological and cardiorespiratory status is important to avoid neurologic and systemic complications.

Hemorheological and hemodynamic analysis of hypervolemic hemodilution therapy for cerebral vasospasm after aneurysmal subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Hypervolemic hemodilution therapy is effective for treating neurological deficits due to cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH). We monitored various hemorheological and hemodynamic parameters to assess the effects of hypervolemic hemodilution therapy in SAH patients with cerebral vasospasm.

METHODS

Ninety-eight patients who underwent early craniotomy for aneurysm clipping surgery after SAH were studied. Fifty-one patients (52.0%) developed symptomatic vasospasm. The hematocrit level and red blood cell aggregability were measured daily from day 1 to day 14, whereas the circulating blood volume and cerebral blood flow were measured periodically. Cardiac output and pulmonary capillary wedge pressure were also measured using a Swan-Ganz catheter.

RESULTS

The hematocrit level was decreased significantly to 29% to 32% by hypervolemic hemodilution therapy. Red blood cell aggregability increased until day 6 but was significantly reduced by therapy. Hypovolemia tended to develop after SAH. However, patients receiving hypervolemic hemodilution therapy became normovolemic to hypervolemic, with a significant increase of cardiac output and pulmonary capillary wedge pressure. At the onset of vasospasm, cerebral blood flow was significantly lower on the operated side than on the contralateral side, and it increased on both sides with therapy.

CONCLUSIONS

Patients with SAH develop hypovolemia, hemodynamic depression, and increased red blood cell aggregability. Hypervolemic hemodilution therapy decreases hematocrit level and red cell aggregability while increasing cardiac output. Improvement of hemorheological and hemodynamic parameters by this therapy can reverse neurological deterioration due to cerebral vasospasm.

Noninvasive monitoring of cardiac output by Doppler echocardiography in patients treated with volume expansion after subarachnoid hemorrhage

OBJECTIVE

To assess the validity and potential clinical utility of cardiac output monitoring using Doppler echocardiography in patients treated with volume expansion after subarachnoid hemorrhage.

DESIGN

Observational study of patients in a randomized, clinical trial.

SETTING

Neurologic intensive care unit.

PATIENTS

Simultaneous, blinded measurements of cardiac output by thermodilution and Doppler echocardiography were performed in 48 patients 1 or 2 days after aneurysmal clipping. Follow-up Doppler echocardiography was performed an average of 3.9 days later (range 3 to 6) in 15 patients assigned to normovolemia and 24 patients assigned to hypervolemia.

INTERVENTION

Patients received supplemental 5% albumin in order to maintain increased (hypervolemia) or normal (normovolemia) cardiac filling pressures.

MEASUREMENTS AND MAIN RESULTS

The overall degree of correlation between the two measures was moderate (r = .67, r2 = .45, p < .0001). Bias and precision calculations (-0.75 +/- 1.34 L/min) showed a tendency for Doppler echocardiography to underestimate thermodilution, particularly when cardiac output was very high. Although hypervolemia patients received more 5% albumin than normovolemia patients, mean percent change in Doppler echocardiography cardiac output did not differ between the two groups. Multiple regression analysis showed that the percent change in Doppler echocardiography cardiac output correlated strongly with changes in heart rate (p < .0001), but not with daily net fluid balance or 5% albumin administration.

CONCLUSIONS

Agreement was poor between Doppler echocardiography and thermodilution measurements of cardiac output, and trends reflected variations in heart rate rather than fluid status. Monitoring of cardiac output by this technique cannot be recommended in patients treated with volume expansion after subarachnoid hemorrhage.

Protection of the brain after aneurysmal rupture

The majority of patients survive the first dangerous hours after an aneurysmal rupture. However, many subsequently succumb as a result of a variety of lethal complications. The most important of these develop as sequelae of the initial ischemia, rebleeding and the delayed onset of vasospasm. Some of these deleterious cascades can be aborted. Since the delayed complications such as vasospastic infarction can be accurately predicted, this is one of rare "strokes" that can have pharmacological pre-treatment. The natural history of rebleeding and vasospasm are described as well as their effects on blood flow, oxygen delivery and metabolism. Strategies to ameliorate acute and delayed ischemia and hypoxia are discussed. Finally, potential pharmacotherapies are detailed.

Coagulopathy with the use of hetastarch in the treatment of vasospasm

The use of colloid agents to achieve hypervolemia in the prevention and treatment of postsubarachnoid hemorrhage (post-SAH) vasospasm is included in the standard of care at many institutions. Risk profiles are necessary to ensure appropriate use of these agents. In a series of 85 patients with recent aneurysmal SAH, 26 developed clinical symptoms of vasospasm. Fourteen of the 26 were treated with hetastarch for volume expansion while the other 12 received plasma protein fraction (PPF). Clinically significant bleeding pathologies were noted in six patients who received hetastarch as a continuous intravenous infusion. Hetastarch increased partial thromboplastin time from a mean of 23.9 seconds to a mean of 33.1 seconds (p < 0.001) in all patients who received infusions of this agent, while no effect was noted in the 12 patients who received PPF infusions. No other coagulation parameters were altered. This study shows an increase in coagulopathy with the use of hetastarch as compared with the use of PPF for the treatment of postaneurysmal vasospasm.

Subarachnoid hemorrhage: an update of pathogenesis, diagnosis and management

Subarachnoid hemorrhage (SAH) remains a devastating neurological disorder, which most commonly develops after rupture of an intracranial aneurysm. Advances have occurred in the areas of epidemiology, diagnostic imaging, medical management and surgical intervention, related to aneurysmal SAH. Interested physicians must become aware of these and other advances to diagnose and manage this potentially lethal disorder more effectively. This review provides information about the pathogenesis and complications of aneurysmal SAH and an update of new and evolving treatment modalities to provide an in-depth overview for the clinician and researcher involved in this rapidly evolving field.

Usefulness of a fiber optic Swan-Ganz catheter to monitor oxygen transport during volume expansion in a patient with ischemic neurologic deficits from aneurysmal subarachnoid hemorrhage

The usefulness of a fiber optic Swan-Ganz catheter to monitor oxygen transport during volume expansion in a patient with ischemic neurologic deficits due to aneurysmal subarachnoid hemorrhage is illustrated. Usefulness of oxygen delivery and oxygen consumption measurements are presented. The role of oxygen transport in addition to cardiac hemodynamics and volume status in the management of these neurologic symptoms is emphasized.

[Anesthesia in surgery for intracranial aneurysms]

The two major neurological complications of subarachnoid haemorrhage (SAH) due to an intracranial aneurysm are rebleeding and delayed cerebral ischaemia related to cerebral vasospasm. The best way to prevent rebleeding is early surgery. Even when surgery is performed within the first 72 hours posthaemorrhage, the risk of cerebral ischaemia due to vasospasm is high. Conventional medical treatment of cerebral vasospasm includes haemodilution, hypervolaemia and increase of arterial blood pressure. Haemodilution is of limited value as the patients suffering from SAH have usually a low haematocrit. The effectiveness of hypervolaemia is controversial and it may worsen cerebral and pulmonary oedema. Systemic hypertension is an effective therapy of vasospasm, but which can only be used once the aneurysm is controlled. Nimodipine and nicardipine, two calcium antagonists, have a beneficial effect on neurologic outcome following SAH. Today, it is still debated whether the beneficial effect of nimodipine results from the vascular effect of the drug or from a direct cerebral cytoprotective mechanism. Early surgery implies that surgeons operate on brains in acute inflammatory state. Thus, it is mandatory to use peroperative techniques improving cerebral exposure. These techniques include infusion of mannitol, lumbar cerebrospinal fluid (CSF) drainage, administration of anaesthetic agents known to decrease cerebral blood flow (CBF) and hypocapnia. Usually, the effect of CSF drainage is very effective and sufficient by itself. The second objective in the peroperative period is to avoid ischaemia. In areas with decreased flow distal to vasospasm, autoregulation is impaired and CBF is directly dependent on cerebral perfusion pressure. Furthermore, the safe practice of transient clipping of vessels supplying the aneurysm has dramatically reduced the indications of controlled hypotension. During temporary clipping, some authors recommend a pharmacological brain protection using barbiturates, etomidate or propofol, but this practice has not been validated by randomized studies. However, it is generally agreed that the arterial pressure should be increased during temporary clipping to improve collateral blood flow and to maintain it after the aneurysm has been secured. To conclude, together with lumbar CSF drainage and transient clipping, the anaesthetic management of the patients should include: maintenance of the arterial blood pressure close to its preoperative level, maintenance of PaCO2 between 30 and 35 mmHg and of normovolaemia through replacement of fluid and blood losses. After completion of surgery, recovery from anaesthesia should be rapid to allow fast diagnosis of neurological complications. The monitoring of the status of consciousness is the key of the diagnosis of early postoperative complications.

Cardiac performance enhancement from dobutamine in patients refractory to hypervolemic therapy for cerebral vasospasm

The use of the beta-agonist dobutamine in combination with hypervolemic preload enhancement of cardiac performance was analyzed in 23 patients who failed to respond to traditional preload enhancement following aneurysmal subarachnoid hemorrhage. The patients ranged in age from 13 to 82 years, and three had a history of cardiac disease. Each patient underwent placement of a flow-directed balloon-tipped catheter and the following measurements were obtained during hyperdynamic therapy: pulmonary artery wedge pressure, central venous pressure, cardiac index, stroke volume index, total peripheral resistance, and left ventricular stroke work index (LVSWI). Mean baseline cardiac function was found to be within normal limits (LVSWI = 47.6 +/- 4.2 gm/min/sq m and cardiac index = 3.30 +/- 0.22 liter/min/sq m). After baseline measurements were recorded, 5% albumin was infused at 300 cc/hr and dobutamine was initiated at a rate of 5 to 10 micrograms/kg/hr. This hyperdynamic therapy with dobutamine in the presence of volume loading resulted in a 52% increase in cardiac index, a 15% increase in LVSWI, and a 21% decrease in total peripheral resistance. The clinical reversal of ischemic symptoms due to subarachnoid hemorrhage was evident in 18 (78%) of the 23 patients.