Steroids Provide Temporary Improvement of Refractory Pain Following Subarachnoid Hemorrhage

Introduction

Evidence for optimal analgesia following subarachnoid hemorrhage (SAH) is limited. Steroid therapy for pain refractory to standard regimens is common despite lack of evidence for its efficacy. We sought to determine if steroids reduced pain or utilization of other analgesics when given for refractory headache following SAH.

Methods

We performed a retrospective within-subjects cohort study of SAH patients who received steroids for refractory headache. We compared daily pain scores, total daily opioid, and acetaminophen doses before, during, and after steroids. Repeated measures were analyzed with a multivariable general linear model and generalized estimating equations.

Results

Included 52 patients treated with dexamethasone following SAH, of whom 11 received a second course, increasing total to 63 treatment epochs. Mean pain score on the first day of therapy was 7.92 (standard error of the mean [SEM] .37) and decreased to 6.68 (SEM .36) on the second day before quickly returning to baseline levels, 7.36 (SEM .33), following completion of treatment. Total daily analgesics mirrored this trend. Mean total opioid and acetaminophen doses on days one and two and two days after treatment were 47.83mg (SEM 6.22) and 1848mg (SEM 170.66), 34.24mg (SEM 5.12) and 1809mg (SEM 150.28), and 46.38mg (SEM 11.64) and 1833mg (SEM 174.23), respectively. Response to therapy was associated with older age, decreasing acetaminophen dosing, and longer duration of steroids. Hyperglycemia and sleep disturbance/delirium effected 28.6% and 55.6% of cases, respectively.

Conclusion

Steroid therapy for refractory pain in SAH patients may have modest, transient effects in select patients.

Evaluating salvage electroconvulsive therapy for the treatment of prolonged super refractory status epilepticus: A case series

BACKGROUND AND OBJECTIVES

Clinicians have treated super refractory status epilepticus (SRSE) with electroconvulsive therapy (ECT); however, data supporting the practice are scant and lack rigorous evaluation of continuous electroencephalogram (cEEG) changes related to therapy. This study aims to describe a series of patients with SRSE treated at our institution with ECT and characterize cEEG changes using a blinded review process.

METHODS

We performed a single-center retrospective study of consecutive patients admitted for SRSE and treated with ECT from January 2014 to December 2022. Our primary outcome was the resolution of SRSE. Secondary outcomes included changes in ictal-interictal EEG patterns, anesthetic burden, treatment-associated adverse events, and changes in clinical examination. cEEG was reviewed pre- and post-ECT by blinded epileptologists.

RESULTS

Ten patients underwent treatment with ECT across 11 admissions (8 female, median age 57 years). At the time of ECT initiation, nine patients had ongoing SRSE while two had highly ictal patterns and persistent encephalopathy following anesthetic wean, consistent with late-stage SRSE. Super-refractory status epilepticus resolution occurred with a median time to cessation of 4 days (interquartile range [IQR]: 3-9 days) following ECT initiation. Background continuity improved in five patients and periodic discharge frequency decreased in six. There was a decrease in anesthetic use following the completion of ECT and an improvement in neurological exams. There were no associated adverse events.

DISCUSSION

In our cohort, ECT was associated with improvement of ictal-interictal patterns on EEG, and resolution of SRSE, and was not associated with serious adverse events. Further controlled studies are needed.

ED BP Management for Subarachnoid Hemorrhage

PURPOSE OF REVIEW

To review most recent literature on management of blood pressure in acute aneurysmal subarachnoid hemorrhage (SAH) and provide practice recommendations for the emergency clinician.

RECENT FINDINGS

There is increased risk of aneurysmal rebleeding with systolic blood pressure (SBP) greater than 160 mmHg in the acute setting. Avoiding large degrees of blood pressure variability improves clinical outcomes in aneurysmal SAH. Acute lowering of SBP to a range of 140-160 mmHg decreases risk of rebleeding while also maintaining cerebral perfusion pressure (CPP) after aneurysmal rupture. Treatment with a short acting antihypertensive agent allows for rapid titration of blood pressure (BP) and reduces BP variability. Elevations in intracranial pressure occur commonly after SAH due to increased intracranial blood volume, cerebral edema, or development of hydrocephalus. Clinicians should be familiar with changes in cerebral autoregulation and effects on CPP when treating elevated BP, in order to mitigate the risk of secondary neurological injury.

Simulation-based assessment of trainee's performance in post-cardiac arrest resuscitation

Objectives

To assess trainees’ performance in managing a patient with post-cardiac arrest complicated by status epilepticus.

Methods

In this prospective, observational, single-center simulation-based study, trainees ranging from sub interns to critical care fellows evaluated and managed a post cardiac arrest patient, complicated by status epilepticus. Critical action items were developed by a modified Delphi approach based on American Heart Association guidelines and the Neurocritical Care Society’s Emergency Neurological Life Support protocols. The primary outcome measure was the critical action item sum score. We sought validity evidence to support our findings by including attending neurocritical care physicians and comparing performance across four levels of training.

Results

Forty-nine participants completed the simulation. The mean sum of critical actions completed by trainees was 10/21 (49%). Eleven (22%) trainees verbalized a differential diagnosis for the arrest. Thirty-two (65%) reviewed the electrocardiogram, recognized it as abnormal, and consulted cardiology. Forty trainees (81%) independently decided to start temperature management, but only 20 (41%) insisted on it when asked to reconsider. There was an effect of level of training on critical action checklist sum scores (novice mean score [standard deviation (SD)] = 4.8(1.8) vs. intermediate mean score (SD) = 10.4(2.1) vs. advanced mean score (D) = 11.6(3.0) vs. expert mean score (SD) = 14.7(2.2))

Conclusions

High-fidelity manikin-based simulation holds promise as an assessment tool in the performance of post-cardiac arrest care.

Simulation-Based Assessment of Graduate Neurology Trainees' Performance Managing Acute Ischemic Stroke

BACKGROUND AND OBJECTIVES

Multidisciplinary acute stroke teams improve acute ischemic stroke management but may hinder trainees' education which in turn may contribute to poorer outcomes in community hospitals upon graduation. Our goal was to assess graduate neurology trainee performance independent of a multi-disciplinary stroke team in the management of acute ischemic stroke, tissue plasminogen activator (tPA)-related hemorrhage, and cerebral herniation syndrome.

METHODS

In this prospective, observational, single-center simulation-based study, participants (sub-interns to attending physicians) managed a patient with acute ischemic stroke followed by tPA-related hemorrhagic conversion leading to cerebral herniation. Critical actions were developed by a modified Delphi approach based on relevant American Heart Association guidelines and the Neurocritical Care Society's Emergency Neurological Life Support protocols. The primary outcome measure was graduate neurology trainees' critical action item sum score. We sought validity evidence to support our findings by comparing trainees' performance across four levels of training.

RESULTS

Fifty-three trainees (including 31 graduate neurology trainees) and five attending physicians completed the simulation. The mean sum of critical actions completed by graduate neurology trainees was 15/22 (68%). Ninety percent of graduate neurology trainees properly administered tPA, 84% immediately stopped tPA infusion following patient deterioration, but only 55% reversed tPA according to guidelines. There was a moderately strong effect of level of training on critical action sum score (level 1 mean score [standard deviation (SD)] = 7.2 (2.8) vs. level 2 mean score (SD) = 12.3 (2.6) vs. level 3 mean score (SD) = 13.3 (2.2) vs. level 4 mean score (SD) = 16.3 (2.4), p < .001, R² = 0.54).

DISCUSSION

Graduate neurology trainees reassuringly perform well in initial management of acute ischemic stroke, but frequently make errors in the treatment of hemorrhagic transformation after thrombolysis, suggesting the need for more education surrounding this low frequency, high-acuity event. High-fidelity simulation holds promise as an assessment tool for acute stroke management performance.

Comparison of Outcomes After Treatment of Large Vessel Occlusion in a Critical Care Resuscitation Unit or a Neurocritical Care Unit

BACKGROUND

Mechanical thrombectomy (MT) has become first-line treatment for patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO). Delay in the interhospital transfer (IHT) of patients from referral hospitals to a comprehensive stroke center is associated with worse outcomes. At our academic tertiary care facility in an urban setting, a neurocritical care and emergency neurology unit (NCCU) receives patients with AIS-LVO from outlying medical facilities. When the NCCU is full, patients with AIS-LVO are initially transferred to a critical care resuscitation unit (CCRU). We were interested in quantifying the numbers of AIS-LVO patients treated in those two units and assessing their outcomes. We hypothesized that the CCRU would facilitate an increase in IHTs and provide care comparable to that delivered by the subspecialty NCCU.

METHODS

We conducted a retrospective study of the medical center's prospective stroke registry for adult IHT patients undergoing MT between 01/01/2015 and 12/31/2017. Primary outcome was time from consultation and request for transfer to arrival (Consult-Arrival). Other outcomes of interest were functional independence, defined as 90-day modified Rankin Scale (mRS) score ≤ 2, and 90-day all-cause mortality. Multivariable logistic regression was performed to assess association between clinical factors, mortality, and functional independence.

RESULTS

We analyzed the records of 128 IHT patients: 87 (68%) were admitted to the CCRU, and 41 (32%) to the NCCU. The two groups had similar baseline characteristics (age, National Institutes of Health Stroke Scale score, Alberta Stroke Program Early Computed Tomography scores [ASPECTS]). The median Consult-Arrival time was shorter for CCRU patients than for the NCCU patients (86 [88‒109] vs 100 [77‒127] [p = 0.031]). The 90-day mortality rates (16 vs 30% [p = 0.052]) and the rates having a mRS score ≤ 2 (31 vs 36% [p = 0.59]) were not statistically different. Multivariable logistic regression showed that each minute of delay in the Consult-Arrival time was associated with 2.3% increase in the likelihood of death (OR 1.023; 95% CI 1.003‒1.04 [p = 0.026]), while high thrombolysis in cerebral infarction score was the only factor that was significantly associated with functional independence at 90 days (OR 2.9; 95% CI 1.4‒6.4 [p = 0.006]).

CONCLUSION

The CCRU increased AIS-LVO patients' access to definitive care and reduced their transfer time from outlying medical facilities while achieving outcomes similar to those attained by patients treated in the subspecialty NCCU. We conclude that a resuscitation unit can complement the NCCU to care for patients in the hyperacute phase of AIS-LVO.

Association of Refractory Pain in the Acute Phase After Subarachnoid Hemorrhage With Continued Outpatient Opioid Use

OBJECTIVE

Little is known about the prevalence of continued opioid use following aneurysmal subarachnoid hemorrhage (aSAH) despite guidelines recommending their use during the acute phase of disease. We sought to determine prevalence of opioid use following aSAH and test the hypothesis that acute pain and higher inpatient opioid dose increased outpatient opioid use.

METHODS

We reviewed consecutively admitted patients with aSAH from November 2015 through September 2019. We retrospectively collected pain scores and daily doses of analgesics. Pain burden was calculated as area under the pain-time curve. Univariate and multivariable regression models determined risk factors for continued opioid use at discharge and outpatient follow-up.

RESULTS

We identified 234 patients with aSAH with outpatient follow-up. Continued opioid use was common at discharge (55% of patients) and follow-up (47% of patients, median 63 [interquartile range 49-96] days from admission). Pain burden, craniotomy, and racial or ethnic minority status were associated with discharge opioid prescription in multivariable analysis. At outpatient follow-up, pain burden (odds ratio [OR] 1.88, 95% confidence interval [CI] 1.5-2.4), depression (OR 3.1, 95% CI 1.1-8.8), and racial or ethnic minority status (OR 2.1, 95% CI 1.1-4.0) were independently associated with continued opioid use; inpatient opioid dose was not.

CONCLUSION

Continued opioid use following aSAH is prevalent and related to refractory pain during acute illness, but not inpatient opioid dose. More efficacious analgesic strategies are needed to reduce continued opioid use in patients following aSAH.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that continued opioid use following aSAH is associated with refractory pain during acute illness but not hospital opioid exposure.

Transfer of Patients with Spontaneous Intracranial Hemorrhage who Need External Ventricular Drain: Does Admission Location Matter?

INTRODUCTION

Patients with spontaneous intracranial hemorrhage (sICH) are associated with high mortality and require early neurosurgical interventions. At our academic referral center, the neurocritical care unit (NCCU) receives patients directly from referring facilities. However, when no NCCU bed is immediately available, patients are initially admitted to the critical care resuscitation unit (CCRU). We hypothesized that the CCRU expedites transfer of sICH patients and facilitates timely external ventricular drain (EVD) placement comparable to the NCCU.

METHODS

This is a pre-post study of adult patients transferred with sICH and EVD placement. Patients admitted between January 2011-July 2013 (2011 Control) were compared with patients admitted either to the CCRU or the NCCU (2013 Control) between August 2013-September 2015. The primary outcome was time interval from arrival at any intensive care units (ICU) to time of EVD placement (ARR-EVD). Secondary outcomes included time interval from emergency department transfer request to arrival, and in-hospital mortality. We assessed clinical association by multivariable logistic regressions.

RESULTS

We analyzed 259 sICH patients who received EVDs: 123 (48%) CCRU; 81 (31%) 2011 Control; and 55 (21%) in the 2013 Control. The groups had similar characteristics, age, disease severity, and mortality. Median ARR-EVD time was 170 minutes [106-311] for CCRU patients; 241 minutes [152-490] (p < 0.01) for 2011 Control; and 210 minutes [139-574], p = 0.28) for 2013 Control. Median transfer request-arrival time for CCRU patients was significantly less than both control groups. Multivariable logistic regression showed each minute delay in ARR-EVD was associated with 0.03% increased likelihood of death (odds ratio 1.0003, 95% confidence interval, 1.0001-1.006, p = 0.043).

CONCLUSION

Patients admitted to the CCRU had shorter transfer times when compared to patients admitted directly to other ICUs. Compared to the specialty NCCU, the CCRU had similar time interval from arrival to EVD placement. A resuscitation unit like the CCRU can complement the specialty unit NCCU in caring for patients with sICH who require EVDs.

Collaboration and Decision-Making on Trauma Teams: A Survey Assessment

Introduction

Leadership, communication, and collaboration are important in well-managed trauma resuscitations. We surveyed resuscitation team members (attendings, fellows, residents, and nurses) in a large urban trauma center regarding their impressions of collaboration among team members and their satisfaction with patient care decisions.

Methods

The Collaboration and Satisfaction About Care Decisions in Trauma (CSACD.T) survey was administered to members of ad hoc trauma teams immediately after resuscitations. Survey respondents self-reported their demographic characteristics; the CSACD.T scores were then compared by gender, occupation, self-identified leader role, and level of training.

Results

The study population consisted of 281 respondents from 52 teams; 111 (39.5%) were female, 207 (73.7%) were self-reported White, 78 (27.8%) were nurses, and 140 (49.8%) were physicians. Of the 140 physician respondents, 38 (27.1%) were female, representing 13.5% of the total surveyed population. Nine of the 52 teams had a female leader. Men, physicians (vs nurses), fellows (vs attendings), and self-identified leaders trended toward higher satisfaction across all questions of the CSACD.T. In addition to the comparison groups mentioned, women and general team members (vs non-leaders) gave lower scores.

Conclusion

Female residents, nurses, general team members, and attendings gave lower CSACD.T scores in this study. Identification of nuances and underlying causes of lower scores from female members of trauma teams is an important next step. Gender-specific training may be necessary to change negative team dynamics in ad hoc trauma teams.

Automated Pupillometry and Detection of Clinical Transtentorial Brain Herniation: A Case Series

Introduction

Transtentorial herniation (TTH) is a life-threatening neurologic condition that typically results from expansion of supratentorial mass lesions. A change in bedside pupillary examination is central to the clinical diagnosis of TTH. Materials and.

Methods

To quantify the changes in the pupillary examination that precede and accompany TTH and its treatment, we evaluated 12 episodes of herniation in three patients with supratentorial mass lesions using automated pupillometry (NeurOptics, Inc., Irvine, CA). Herniation was defined clinically by the onset of fixed and dilated pupils in association with decreased levels of consciousness. Automated pupillometry was measured simultaneously with the bedside clinical examination, but the clinical team was blinded to these results and could not act on the data. Data from the pupillometer were downloaded 1-2 times per week onto a secured laptop, and data processing was facilitated by the use of Mathematica 8.0.

Results

Neurologic Pupil Index measurements, values generated by the pupillometer based on an algorithm that incorporates pupillary size and reactivity in a normal population, were found to be abnormal before 73% of TTHs. This abnormality occurred at a median of 7.4 h before TTH. All episodes of TTH were reversed after clinical intervention at a median of 43 min after the event. The value did not fall to 0 in 42% of clinical herniations, but it did decrease to very abnormal values of 0.5-0.8.

Conclusions

The potential of automated pupillometry to guide the management of severely injured neurologic patients is intriguing and warrants further study in the critical care unit and beyond. The utility of a portable device in the combat setting may allow for triage of patients with severe neurologic injury.

Abstract WMP104: Complement System is Acutely Activated in Humans After Intracerebral Hemorrhage

Introduction: Intracerebral hemorrhage (ICH) generates a complex local and systemic inflammatory response, but prior studies have neglected the role of the complement system. While animal models of ICH have suggested complement is a key regulator of inflammation, human data are lacking. We investigated whether the complement system was activated in ICH patients.

Hypothesis: We hypothesized complement system activation product levels would be acutely elevated in ICH patients compared to matched controls. We also examined the association of these complement fragment levels with established ICH severity markers and perihematomal edema (PHE) growth rates.

Methods: We identified 25 ICH patients whose blood was collected within 5 days post stroke at the University of Maryland Medical Center from June 2016 to September 2017 as part of the Recovery After Cerebral Hemorrhage (REACH) and Genetic and Environmental Risk Factors for Hemorrhagic Stroke (GERFHS) studies. C3a, C5a, and sC5b-9 levels were measured via ELISA (Quidel, San Diego, CA) in patients and healthy controls matched for age, sex, and race. Six patients were excluded from PHE growth measurement for lack of available follow-up CT or MRI scans. Hematoma and PHE volumes were measured on the initial CT scan and the follow-up CT scan (or MRI scan if CT not done) closest to 72 hours post stroke via a semi-automated method.

Results: Mean C3a (82.4 versus 49.2 ng/mL, p = 0.01), C5a (19.2 versus 9.1 ng/mL, p = 0.00005), and sC5b-9 (3000 versus 246 ng/mL, p = 0.00006) levels were elevated in ICH patients relative to matched controls. In secondary analyses, C5a level was correlated with presence of intraventricular hemorrhage (correlation coefficient 0.51, p = 0.03) and modified Graeb score (correlation coefficient 0.50, p = 0.03). Complement fragment levels were not correlated with PHE growth rates, age, ICH size, ICH location, or presence of at least 2 systemic inflammatory response syndrome (SIRS) criteria.

Conclusions: Activated complement fragments C3a, C5a, and sC5b-9 are significantly (several-fold) elevated in ICH patients independently of age, ICH size, and ICH location. Considering complement’s role in initiating and augmenting inflammation, it represents a potential novel therapeutic target.

Emergency Department Approach to the Patient with Suspected Central Nervous System Infection

Central nervous system (CNS) infections require early recognition and aggressive management to improve patient survival and prevent long-term neurologic sequelae. Although early detection and treatment are important in many infectious syndromes, CNS infections pose unique diagnostic and therapeutic challenges. The nonspecific signs and symptoms at presentation, lack of characteristic infectious changes in laboratory and imaging diagnostics, and closed anatomic and immunologically sequestered space each present challenges to the emergency physician. This article proposes an approach to the clinical evaluation of patients with suspected CNS infection and highlights methods of diagnosis, treatment, and complications associated with CNS infections.

The neurology literature 2016

Emergency neurology is a complex and rapidly changing field. Its evolution can be attributed in part to increased imaging options, debates about optimal treatment, and simply the growth of emergency medicine as a specialty. Every year, a number of articles published in emergency medicine or other specialty journals should become familiar to the emergency physician. This review summarizes neurology articles published in 2016, which the authors consider crucial to the practice of emergency medicine. The articles are categorized according to disease process, with the understanding that there can be significant overlap among articles.

Neurotrauma

Neurotrauma continues to be a significant cause of morbidity and mortality. Prevention of primary neurologic injury is a critical public health concern. Early and thorough assessment of the patient with neurotrauma with high index of suspicion of traumatic spinal cord injuries and traumatic vascular injuries requires a multidisciplinary approach involving prehospital providers, emergency physicians, neurosurgeons, and neurointensivists. Critical care management of the patient with neurotrauma is focused on the prevention of secondary injuries. Much research is still needed for potential neuroprotection therapies.

Calcium, magnesium, and phosphate abnormalities in the emergency department

Derangements of calcium, magnesium, and phosphate are associated with increased morbidity and mortality. These minerals have vital roles in the cellular physiology of the neuromuscular and cardiovascular systems. This article describes the pathophysiology of these mineral disorders. It aims to provide the emergency practitioner with an overview of the diagnosis and management of these disorders.

Strategies for the use of mechanical ventilation in the neurologic intensive care unit

Mechanical ventilation in neurologically injured patients presents unique challenges. Patients with acute neurologic injuries may require mechanical ventilation for reasons beyond respiratory failure. There is also a subset of pulmonary pathologic abnormality directly associated with neurologic injuries. Balancing the need to maintain brain oxygenation, cerebral perfusion, and control of intracranial pressure can be in conflict with concurrent ventilator strategies aimed at lung protection. Weaning and liberation from mechanical ventilation also require special considerations. These issues are examined in the ventilator management of the neurologically injured patient.

Temperature affects thrombolytic efficacy using rt-PA and eptifibatide, an in vitro study

The potential for hypothermia as a neuroprotectant during stroke has led to its increase in clinical use. At the same time, combination pharmaceutical therapies for ischemic stroke using recombinant tissue plasminogen activator (rt-PA), and GP IIb-IIIa inhibitors, such as Eptifibatide (Epf ), are under study. However, there is little data on how the reactions triggered by these agents are impacted by temperature. Here, clot lysis during exposure to the combination of rt-PA and Epf is measured in an in vitro human clot model at hypothermic temperatures. The hypothesis is that lytic efficacy of rt-PA and Epf decreases with decreasing temperature. Whole blood clots from 31 volunteers were exposed to rt-PA (0.5 μg/mL) and Epf (0.63 μg/mL) in human fresh-frozen plasma (rt-PA+Epf ), rt-PA alone in plasma (rt-PA Alone), or to plasma alone (Control), at temperatures from 30°C to 37°C, for 30 minutes. Clot lysis was measured using a microscopic imaging technique; the mean fractional clot loss (FCL) at 30 minutes was used to determine lytic efficacy. Temperature had a significant impact on FCL in clots exposed to rt-PA+Epf, with the FCL being lower at 30°C to 36°C than at 37°C. The FCL remained significantly higher for rt-PA+Epf–treated clots than Controls regardless of temperature, with the exception of measurements made at 30°C when no significant differences in the FCL were observed between groups. The use of hypothermia as a neuroprotectant may negatively impact the therapeutic benefit of thrombolytic agents.

Abstract 2589: Temperature Dependence of Lysis with Tissue Plasminogen Activator, Eptifibatide, and Ultrasound

Introduction: Recombinant tissue plasminogen activator (rt-PA) is the only FDA approved thrombolytic therapy for acute ischemic stroke. Recent studies have shown hypothermia to be beneficial in patient outcome in stroke. However, rt-PA is less effective at temperatures less than 37°C. Interest in improving the lytic efficacy of rt-PA thrombolysis has led to the study of adjunctive therapies such as GP IIb-IIIa inhibitors like eptifibatide (Epf) and ultrasound (US) enhanced thrombolysis. However, the thrombolytic efficacy of combination therapy with rt-PA over a clinically applicable temperature range is unknown.

Objective: The effects of temperature on the thrombolytic efficacy of combination rt-PA-driven thrombolysis were determined in an in-vitro human clot model.

Methods: Human whole blood clots were made from blood obtained from volunteers, after local Institutional Review Board approval. Clots were made in 20-µL pipettes and placed in a water tank for microscopic visualization during treatment. Sample clots were exposed to human fresh-frozen plasma (hFFP) alone (Control); hFFP and rt-PA ([0.5 µg/ml]; “+rt-PA”); hFFP, rt-PA ([0.5 µg/ml]), and Epf ([0.63 µg/ml]; “+Epf”); and hFFP, rt-PA, Epf, and ultrasound supplied by a 2-MHz transcranial Doppler (TCD) unit (“+TCD”). Exposures were for 30 minutes at 30-37°C. Clot width was measured using a microscopic imaging technique and mean percent fractional clot loss (FCL) at 30 minutes was used to determine thrombolytic efficacy.

Results: Each of 15 treatment groups had a minimum of 6 clots (range: 6-148) from 2 different donors (range: 2-21), for a total of 409 clots. At 37°C, FCLs for +rt-PA and +TCD groups were 44% (95% Confidence Interval: 37-52%) and 59% (54-64%) respectively (p<0.01). At 30°C, FCLs for +rt-PA and +TCD groups were 32% (27-36%) and 30% (26-33%) respectively (p not significant).

Conclusion: Combination therapy using rt-PA, Epf, and 2-MHz US exhibits temperature dependence over a clinically applicable temperature range.