Diagnostic Accuracy of Transcranial Doppler for Brain Death Confirmation: Systematic Review and Meta-Analysis.

BACKGROUND AND PURPOSE: Transcranial Doppler is a useful ancillary test for brain death confirmation because it is safe, noninvasive, and done at the bedside. Transcranial Doppler confirms brain death by evaluating cerebral circulatory arrest. Case series studies have generally reported good correlations between transcranial Doppler confirmation of cerebral circulatory arrest and clinical confirmation of brain death. The purpose of this study is to evaluate the utility of transcranial Doppler as an ancillary test in brain death confirmation. MATERIALS AND METHODS: We conducted a systematic review of the literature and a diagnostic test accuracy meta-analysis to compare the sensitivity and specificity of transcranial Doppler confirmation of cerebral circulatory arrest, by using clinical confirmation of brain death as the criterion standard. RESULTS: We identified 22 eligible studies (1671 patients total), dating from 1987 to 2014. Pooled sensitivity and specificity estimates from 12 study protocols that reported data for the calculation of both values were 0.90 (95% CI, 0.87-0.92) and 0.98 (95% CI, 0.96-0.99), respectively. Between-study differences in the diagnostic performance of transcranial Doppler were found for both sensitivity (I(2) = 76%; P < .001) and specificity (I(2) = 74.3%; P < .001). The threshold effect was not significant (Spearman r = -0.173; P = .612). The area under the curve with the corresponding standard error (SE) was 0.964 ± 0.018, while index Q test ± SE was estimated at 0.910 ± 0.028. CONCLUSIONS: The results of this meta-analysis suggest that transcranial Doppler is a highly accurate ancillary test for brain death confirmation. However, transcranial Doppler evaluates cerebral circulatory arrest rather than brain stem function, and this limitation needs to be taken into account when interpreting the results of this meta-analysis.

Effect of body positioning during transcranial Doppler detection of right-to-left shunts.

We adopted an expanded transcranial Doppler (TCD) protocol to evaluate if additional injections of agitated saline in different positions would improve shunt detection or grading. We report the safety and feasibility of this expanded contrast TCD protocol. Patients with ischemic stroke were evaluated. The standard protocol for RLS detection was followed and expanded after the initial injection in the supine position to the right lateral decubitus, upright sitting, and sitting with right lateral leaning. Changes in blood pressure, heart rate, and any subjective complaints were noted. Changes in body position and additional agitated saline injections were tolerated. Right-to-left shunt (RLS) was detected in 35% of patients (n = 55). If the initial supine testing was negative, all subsequent positions/injections were also negative for RLS. However, if the supine injection was positive for RLS, the change in body positions increased the microbubble (microB) count in eight of 19 (42%) RLS-positive patients. The mean microB count in RLS-positive patients was 20 (95% CI: 9-32). The use of three additional body positions increased the microB count to 73 (95% CI: 13-132). The highest microB yield was achieved in the upright sitting position. Our findings support the safety and feasibility of the expanded TCD protocol. If the initial supine Valsalva-aided contrast TCD test is negative, there may be no need to study the patient in additional positions. However, if microB are detected in the supine position, additional testing for RLS in alternative positions may be found to be worthwhile.

Thrombotic occlusion of the common carotid artery (CCA) in acute ischemic stroke treated with intravenous tissue plasminogen activator (TPA).

Although common carotid artery (CCA) occlusions are rare, acute clinical presentations vary from mild to devastating strokes primarily due to tandem occlusions in the intracranial arteries. Three patients with acute CCA occlusions were treated with systemic tissue plasminogen activator (TPA). Blood pressures were kept at the upper limits allowed with TPA therapy with fluid balance and the 'head-down' position. Recanalization occurred in intracranial vessels only. Marked early neurological improvement occurred in two of three patients. CCA occlusions should not be considered contra-indication to systemic thrombolysis.

Postpartum cerebral angiopathy: atypical features and treatment with intracranial balloon angioplasty.

Postpartum cerebral angiopathy (PCA) is an uncommon cause of ischemic and hemorrhagic stroke in young women. It is usually clinically benign and not relapsing. We describe a patient with nonhemorrhagic PCA who had an atypical progressive neurological deficit from bilateral hemisphere watershed ischemia despite treatment with aggressive medical therapy and intracranial balloon angioplasty.

Should mild or moderate stroke patients be admitted to an intensive care unit?

BACKGROUND AND PURPOSE: Inhospital placement of patients with mild (National Institutes of Health Stroke Scale [NIHSS] score <8) or moderate (NIHSS 8 through 16) acute strokes is variable. We assessed the outcome of such patients based on intensive care unit (ICU) versus general ward placement. METHODS: We reviewed 138 consecutive patients admitted within 24 hours of stroke onset to 2 physically adjacent hospitals with different admitting practices. Outcome measures included complication rates, discharge Rankin scale score, hospital discharge placement, costs, and length of stay (LOS). RESULTS: Hospital A, a 626-bed university-affiliated hospital, admitted 43% of mild and moderate strokes (MMS) to an ICU (26% of mild, 74% of moderate), whereas hospital B, a 618-bed community facility, admitted 18% of MMS to an ICU (3% of mild, 45% of moderate; P<0.004). There were no significant differences in outcomes between the 2 hospitals. Analysis of only patients admitted to hospital A, and of all patients, demonstrated that mild stroke patients admitted to the general ward had fewer complications and more favorable discharge Rankin scale scores than similar patients admitted to an ICU. There was no statistically significant difference in LOS, but total room costs for a patient admitted first to the ICU averaged $15 270 versus $3638 for admission directly to the ward. CONCLUSIONS: While limited by the retrospective nature of our study, routinely admitting acute MMS patients to an ICU provides no cost or outcomes benefits.

Near infrared spectroscopy (NIRS) distinguishes seizure types.

Near infrared spectroscopy (NIRS) is a noninvasive method for bedside measurement of cerebral oxygenation (SaO(2)). The purpose of this study was to establish differences in SaO(2)for complex partial seizures (CPS) and rapidly secondarily generalized CPS (RCPS). We studied eight adults with medically refractory epilepsy undergoing evaluation for temporal lobectomy. We continually measured cerebral SaO(2)via a Somanetic Invos 3100a cerebral oximeter, pre-ictal (5 minutes), ictal, immediate (30 seconds) post-ictal, and late post-ictal (5 minutes after ictus). Seventeen seizures (12 CPS, four RCPS and one subclinical) were recorded in eight patients. The percentage change in cerebral SaO(2)from pre-ictal to ictal periods was derived. Cerebral SaO(2)increased (percentage change, mean: 16.6, SD: 13.9) for CPS and decreased (percentage change, mean: 51.1, SD: 18.1) for RCPS. No change in cerebral oximetry was recorded for the subclinical seizure. Post-ictal (immediate and late) increase in cerebral SaO(2)was seen for 11 of the 17 seizures (nine CPS and two RCPS). Peripheral SaO(2)rose greater than 93% for all CPS and the subclinical seizure, but decreased between 78 and 84% during RCPS. These results suggest NIRS distinguishes cerebral SaO(2)patterns between CPS and RCPS. The decrease in peripheral SaO(2), however, may account for the decrease in cerebral SaO(2)seen in generalized seizures.

Mitochondrial maculopathy: geographic atrophy of the macula in the MELAS associated A to G 3243 mitochondrial DNA point mutation.

PURPOSE: To report ocular findings in the mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS syndrome) in a family with the A to G 3243 mitochondrial (mt) DNA point mutation. METHODS: Case reports. Ocular findings are described from four family members with the MELAS associated A to G 3243 mt DNA point mutation. RESULTS: Findings included ophthalmoplegia, neurosensory deafness, reduction of photopic and scotopic electroretinogram b-wave amplitudes, and myopathy, as well as macular retinal pigment epithelial atrophy. No family members had nyctalopia, attenuation of retinal blood vessels, or retinal bone spicule pigmentation. CONCLUSION: The finding of slowly progressive macular retinal pigment epithelial atrophy expands the reported phenotypic diversity of patients with A3243G mt DNA mutations.

Reversible segmental cerebral arterial vasospasm and cerebral infarction: possible association with excessive use of sumatriptan and Midrin.

OBJECTIVE: To describe a patient who developed reversible segmental cerebral arterial vasospasm and cerebral infarction while taking excessive amounts of sumatriptan succinate and a combination drug (Midrin) consisting of isometheptene mucate, 65 mg, dichloralphenazone, 100 mg, and acetaminophen, 325 mg. DESIGN: Case report. SETTING: Tertiary care center. PATIENT: A 43-year-old man who developed a left occipital infarct after taking a total of 23 sumatriptan succinate tablets (25 mg per tablet) and 32 Midrin tablets during a 7-day period and who on digital subtraction angiography was shown to have segmental cerebral arterial narrowing in multiple vessels. An extensive evaluation for other possible risk factors for cerebral infarction was unrevealing. MAIN OUTCOME AND RESULTS: Discontinuation of sumatriptan and Midrin regimens and administration of nicardipine hydrochloride led to nearly total resolution of the angiographic findings, and the patient had no recurrent strokes. CONCLUSIONS: One should consider the diagnosis of drug-induced vasospasm in patients with cerebral infarction and a history of excessive use of sumatriptan and Midrin. The initial angiographic abnormalities may resemble those found in patients with primary angiitis of the central nervous system.

Isolated vertigo as a manifestation of vertebrobasilar ischemia.

OBJECTIVE: We sought to demonstrate that isolated episodes of vertigo can be the only manifestation of vertebrobasilar ischemia. BACKGROUND: Isolated persistent vertigo is classically ascribed to labyrinthine disorders and is only rarely considered to reflect vertebrobasilar ischemia. METHODS: We retrospectively analyzed all of the records of the Saint Louis University Stroke Registry between January 1, 1992 and September 1, 1993. We set out to identify those patients discharged with a diagnosis of transient ischemic attack (TIA) in the vertebrobasilar system. We reviewed their clinical records and the results of their diagnostic studies. RESULTS: We screened 600 admissions and found 29 patients with vertebrobasilar circulation TIAs. Of these, five men and one woman had episodic vertigo for at least 4 weeks as their only presenting symptom. All six patients had one of two abnormal patterns on magnetic resonance angiography (MRA): focal basilar stenosis or widespread vertebrobasilar slow flow. In three patients, the MRA findings were confirmed by cerebral angiography. Five patients were treated with warfarin and one with aspirin. Two patients developed brainstem infarctions, one of them fatal. CONCLUSIONS: Isolated vertigo can be the only manifestation of vertebrobasilar ischemia. Its frequency may be underestimated in clinical practice. Noninvasive testing is helpful both for diagnosis and follow-up.

Cerebrovascular hemodynamic inefficiency of premature ventricular contractions.

Transcranial Doppler (TCD) measurements of middle cerebral artery (MCA) blood flow velocities were recorded and synchronized with electrocardiographic (EKG) recordings in 52 EKG/TCD complexes in 4 patients. Thirty-seven normal sinus beats and 13 conductive and 2 nonconductive premature ventricular contractions (PVCs) were examined. Mean velocities averaged 45 +/- 4 cm/sec for normal sinus rhythm (NSR) vs 26 +/- 4 cm/sec in the PVC group (P = 0.007). Peak systolic velocities averaged 74 +/- 6 cm/sec for the NSR and 45 +/- 7 cm/sec in the PVC group (P = 0.016). The latency between the QRS complexes and corresponding TCD wave forms (QRS-SU) averaged 0.12 +/- 0.03 sec in NSR AND 0.17 +/- 0.04 sec for the PVC group (P < 0.001). In addition, QRS-SU was inversely related to all velocities. PVCs appeared to be less hemodynamically efficient than NSR. The lower blood flow velocities and increased QRS-SU may result from lower stroke volume and delayed ventricular contraction associated with the aberrant QRS complex.

Therapeutic Intervention Scoring System used in the care of patients in pentobarbital-induced coma to determine nurse-patient ratios.

BACKGROUND: Critical care patients generally require extensive interventions, thereby consuming a large percentage of healthcare resources. Induced pentobarbital coma for the management of increased intracranial pressure is one such intervention, required to maintain patient stability. Quantification of these interventions, as well as the amount of nursing work required, has not been addressed in the literature. OBJECTIVE: To use the Therapeutic Intervention Scoring System to analyze and quantify how interventions affect nurse-patient ratios in the management of patients in pentobarbital coma for refractory increased intracranial pressure. METHODS: The medical records of patients with subarachnoid hemorrhage from aneurysmal rupture and subsequent increased intracranial pressure, in whom pentobarbital coma was salvage therapy, were reviewed retrospectively. The Therapeutic Intervention Scoring System was used to quantify the number of interventions required before, during, and after coma induction. The data were analyzed and daily Therapeutic Intervention Scoring System scores correlated with serum pentobarbital levels. Typically, a critical care nurse can manage a patient caseload of 40 to 50 Therapeutic Intervention Scoring System points. By quantifying the interventions, the score reflected the amount of care required to manage the patient in barbiturate coma. RESULTS: The intensity of interventions correlated with the level of coma, length of time in coma, and associated complications. CONCLUSIONS: The scores indicated the intensity of interventions used in pentobarbital coma and the use of resources. Nursing care and complications involved with this therapy were quantified and nurse-patient ratios were established.

Sinus arrest after administration of intravenous metoclopramide.

BACKGROUND: Sinus arrest is a rare complication of metoclopramide administration. CASE DESCRIPTION: A 51-year-old woman developed Guillain-Barre syndrome and severe dysautonomia. Metoclopramide was administered for the treatment of gastroparesis. Sinus arrest followed drug administration on several occasions and on rechallenge. CONCLUSIONS: After reviewing the literature and discussing possible etiologies for this unusual adverse drug reaction in this setting, we recommend that metoclopramide be used with caution in patients prone to develop bradyarrythmias, particularly those with dysautonomias and Guillain-Barre syndrome.

Quantifying nursing care in barbiturate-induced coma with the therapeutic intervention scoring system.

The use of pentobarbital-induced coma to manage intractable increased intracranial pressure remains a viable option in the acutely brain-injured patient. In a retrospective review of 15 patients with a variety of neurological injuries at our institution, it was found that aggressive management of respiratory, hemodynamic, metabolic and neurological status was required with the use of pentobarbital coma. A scoring system to determine the amount of interventions and nursing care required was used in the review. The Therapeutic Intervention Scoring System (TISS) demonstrated that with the acuity of illness, there were predictably increased interventions. As a method for quantifying the amount of care in this group of individuals, scoring of the interventions before, during, and after barbiturate coma was assessed. The findings demonstrated a significant difference in the scoring. Mean scores were: pre-treatment = 31.8, s.d. = 7.5; during = 41.7, s.d. = 2.0; post-treatment = 36.4, s.d. = 5.2, p < 0.01. Further modifications of the TISS to include current neuroscience therapies, such as the monitoring of cerebral oxygen extraction by jugular bulb catheterization, may increase the utility of the TISS.

Central nervous system modulation of respiratory function in the critically ill.

Neural control of ventilation is exercised at multiple levels and includes an array of sensors and diverse control areas. Abnormalities in the neural control of ventilation are seen in a variety of pathologic states and illnesses commonly seen in critical care. As is common with any complex system, multiple feedback loops work within the system. Interactions between drive and performance are common in mechanically ventilated patients, especially during weaning from the ventilator. Better understanding of these interactions will hopefully lead to better understanding of the common pathologic processes involving control of breathing.

Code stroke. An attempt to shorten inhospital therapeutic delays.

BACKGROUND AND PURPOSE: Significant delays often occur during the treatment of patients with acute stroke. Some of those delays occur in the hospital. We attempted to shorten inhospital treatment intervals by creating a rapid-response system, similar to that available for cardiac arrest, that would allow the stroke team to be available within a few minutes to care for stroke victims. METHODS: We connected all beepers (pocket pagers) of stroke team members to a common access number and instructed the emergency staff to activate that number immediately upon arrival of a stroke victim. We monitored the response time and treatment interval for patients who were treated after this system was activated (Code Stroke patients) during the first 3 months of its availability and compared the results to those of patients seen for similar reasons during the study period but without the use of Code Stroke (control patients). RESULTS: A total of 12 Code Stroke patients were available for analysis, representing 12% of all patients (n = 98) seen in the emergency department for ischemic stroke during the study period. The remaining 86 patients constituted the control group. The mean time to evaluation of a Code Stroke patient by a stroke team member was 4.8 minutes (range, 2 to 7 minutes), and the mean time to treatment institution was 30 minutes (range, 10 to 120 minutes). There were significant differences between the consultation intervals in the two groups (P < .05). There was only a trend of a difference between treatment institution intervals (P = .06). CONCLUSIONS: It is possible to shorten inhospital treatment delays by instituting rapid-response systems within individual institutions.

Hyperdense basilar artery. An early computed tomography sign of thrombosis.

Noncontrast computed tomographic scans (CT scans) may show a hyperdense basilar artery before a brainstem infarct is visualized. This early sign should assist clinicians in confirming the diagnosis of basilar artery thrombosis. In a review of admission records of 750 patients with acute cerebrovascular disease from July 1991 to June 1993, at Saint Louis University Hospital, 20 patients were identified with clinical signs of nonlacunar, vertebrobasilar distribution infarction. Eight of these had pontomesencephalic ischemia. Their neuroimaging studies and medical records were evaluated. Four patients with acute clinical signs of pontomesencephalic infarction were found to have a hyperdense basilar artery on CT scans. The scans of 2 patients were excluded because of dolichoectasia; in the other 2 patients, the basilar artery appeared normal on the CT scan. The hyperdense basilar artery was detected within the early hours of neurological symptoms and often was the only detectable abnormality on the scan. In 3 patients extensive brainstem infarcts subsequently developed and they died. Basilar artery thrombosis was confirmed by pathological study in all these patients. In the fourth patient basilar artery occlusion and a large pontine infarct were evident by magnetic resonance imaging and angiography. A hyperdense basilar artery is a common feature on CT scans of patients presenting with an early clinical diagnosis of thrombosis. Untreated, the hyperintense basilar artery often portends a poor prognosis. Its ready recognition should guide further interventional studies and treatment.

Delayed sequelae of vertebral artery dissection and occult cervical fractures.

We report three patients who developed delayed (ie, more than a week after the injury) symptoms of vertebrobasilar ischemia following motor vehicle accidents. The patients all had angiographic evidence of vertebral artery dissection and, upon further evaluation, occult fractures of the second cervical vertebra that were not detected by simple cervical spine radiography and required polytomography or CT for diagnosis. Vertebral artery dissection can result from occult cervical spine fractures and may present with delayed symptoms of brain ischemia.