ASNM and ASN joint guidelines for transcranial Doppler ultrasonic monitoring: An update.

Today, it seems prudent to reconsider how ultrasound technology can be used for providing intraoperative neurophysiologic monitoring that will result in better patient outcomes and decreased length and cost of hospitalization. An extensive and rapidly growing literature suggests that the essential hemodynamic information provided by transcranial Doppler (TCD) ultrasonography neuromonitoring (TCDNM) would provide effective monitoring modality for improving outcomes after different types of vascular, neurosurgical, orthopedic, cardiovascular, and cardiothoracic surgeries and some endovascular interventional or diagnostic procedures, like cardiac catheterization or cerebral angiography. Understanding, avoiding, and preventing peri- or postoperative complications, including neurological deficits following abovementioned surgeries, endovascular intervention, or diagnostic procedures, represents an area of great public and economic benefit for society, especially considering the aging population. The American Society of Neurophysiologic Monitoring and American Society of Neuroimaging Guidelines Committees formed a joint task force and developed updated guidelines to assist in the use of TCDNM in the surgical and intensive care settings. Specifically, these guidelines define (1) the objectives of TCD monitoring; (2) the responsibilities and behaviors of the neurosonographer during monitoring; (3) instrumentation and acquisition parameters; (4) safety considerations; (5) contemporary rationale for TCDNM; (6) TCDNM perspectives; and (7) major recommendations.

Surgical Treatment of Patients with Full Tracheal Rings: Our Experience.

Introduction: Complete tracheal rings are a rare pathology occurring in 1 out of 100,000 live births. It is rare isolated tracheal or tracheobronchial anomaly resulting from abnormal cartilage growth, forming a complete ring, and leading to airway stenosis. A sliding tracheoplasty, primarily described by Tsang et al. and later widely presented by Grillo et al., overlaps the tracheal stenosing segments and shortens the trachea itself, and thus increases the diameter and circumference of the stenosing area double up. Materials and Methods: We have performed four slide tracheoplasties in the period between February 2019 and December 2020 in children who underwent medical treatment in the department of thoracic surgery in our center. Median age was 10 ± 5.5 months (2 months-1 year 6 months). Median weight was 6.9 ± 1.9 kg (4.5-9 kg). Slide tracheoplasty was performed using central venoarterial extracorporeal membrane oxygenation in 3 cases and using cardiopulmonary bypass in 1 case. Results: Patients were on artificial lung ventilation for 2-6 days in the postoperative period. Patients were discharged 14-18 days after the surgery. There were no lethal outcomes in our study. Discussion: Long segment congenital tracheal stenosis is an often and serious life-threatening anatomical malformation that bounded the length of trachea >50%. There is no unique treatment strategy for patients with such pathology. Sliding tracheoplasty can be recommended for all, but not for the shortest segments of stenosis, as it creates permissible voltage fluctuations during tracheal anastomosis. Excellent results in management of such severe patients can be achieved only through the collaboration of multidisciplinary team of specialists sharing organized and consistent patient-oriented approach.

Latin American Consensus Statement for the Use of Contrast-Enhanced Transcranial Ultrasound as a Diagnostic Test for Detection of Right-to-Left Shunt.

BACKGROUND: The role of patent foramen ovale is a field of debate and current publications have increasing controversies about the patients' management in young undetermined stroke. Work up with echocardiography and transcranial Doppler (TCD) can aid the decision with better anatomical and functional characterization of right-to-left shunt (RLS). Medical and interventional strategy may benefit from this information. SUMMARY: a group of experts from the Latin American participants of the Neurosonology Research Group (NSRG) of World Federation of Neurology created a task force to review literature and describe the better methodology of contrast TCD (c-TCD). All signatories of the present consensus statement have published at least one study on TCD as an author or co-author in an indexed journal. Two meetings were held while the consensus statement was being drafted, during which controversial issues were discussed and voted on by the statement signatories. The statement paper was reviewed and approved by the Executive Committee of the NSRG of the World Federation of Neurology. The main objective of this consensus statement is to establish a standardization of the c-TCD technique and its interpretation, in order to improve the informative quality of the method, resulting in expanding the application of TCD in the clinical setting. These recommendations optimize the comparison of different diagnostic methods and encourage the use of c-TCD for RLS screening and complementary diagnosis in multicenter studies.

Comparison of the Laparoscopic and Open Methods of Gastrostomy at Neonates and Infants Up To Three Months of Age.

Background: An open surgical intervention is a common approach for gastrostomy tube placement in neonates and infants. Also available, however less often used, is a laparoscopic technique for low-profile gastrostomy tube (button) placement. In this study we compare the pre-, intra-, and post-procedural outcomes of each technique. Methods: We retrospectively evaluated all open and laparoscopically inserted gastrostomies at our department from January 2002 to December 2016 and compared them in terms of operative parameters and outcomes. Results: In the study interval, 44 open and 90 laparoscopically placed low-profile (button) gastrostomies were performed. There were no significant differences in gender distribution, mean age (42.54 versus 34.16 days), and mean weight (3311 versus 3476 g). The frequency of concomitant Nissen fundoplication was higher in the laparoscopy group (18% versus 47%; P < .05). The duration of G-tube placement by laparotomy was significantly longer (mean difference 16 minutes), than by laparoscopy, as were time periods between G-tube insertion and the onset of first feeding (mean differences 8.4 and 19.6 hours, respectively). Children in the laparoscopy group spent nearly 15 fewer days in the hospital than those who received a G-tube by laparotomy (29.0 versus 13.9; P < .05). Major complications were observed in 3 (6.82%) patients in the laparotomy group in the form of gastric content leak into the abdominal cavity and resulting peritonitis; complications were lower in the laparoscopy group (68.18% versus 13.33%; P = .03). Conclusions: Compared with open gastrostomy, the laparoscopic approach appears to be advantageous with respect to procedural duration, initiation of feedings, hospitalization duration, and rate of complications. Another difference was the frequency of concomitant Nissen fundoplication. Further prospective studies may determine the role of these patient-specific factors regarding who benefits most from the laparoscopic technique.

Cerebral High-Intensity Transient Signals during Pediatric Cardiac Catheterization: A Pilot Study Using Transcranial Doppler Ultrasonography.

BACKGROUND AND PURPOSE: Cerebral emboli are one potential cause of acute brain injury in children with congenital heart disease (CHD) undergoing cardiac catheterization. In this pilot study using transcranial Doppler (TCD) ultrasonography, we sought to evaluate the incidence, burden, and circumstances of cerebral high-intensity transient signals (HITS), presumably representing emboli, during pediatric cardiac catheterization. METHODS: Emboli monitoring of the right middle cerebral artery was performed in five children. HITS, counted offline, were defined as unidirectional signals associated with audible "chirp" and sinusoidal correlation. HITS were grouped as single, >10 HITS ("cluster"), or HITS "with curtain effect" per 3-5 cardiac cycles. Cerebral blood flow velocity (CBFV) and pulsatility index (PI) were recorded after anesthetic induction (baseline). RESULTS: Total HITS in the cohort was 1,697 (790 single HITS, 606 HITS within clusters, and 301 HITS within curtains). HITS in clusters and curtains comprised 53% (907/1,697) of total HITS, and occurred in 44 clusters/curtains. Events associated with clusters/curtains included left ventricular angiography (39%; 17/44), right ventricular angiography (16%; 7/44), device placement (16%; 7/44), heparin bolus (9%; 4/44), pulmonary artery angiography (9%; 4/44), venous access (5%; 2/44), right atrial angiography (2%; 1/44), arterial access (2%; 1/44), and hemodynamic measurements (2%; 1/44). No patient had clinically detectable neurologic injury. CONCLUSIONS: HITS are common during pediatric cardiac catheterization, and associated with procedural factors. Whether curtains/clusters are worse than single, repetitive HITS is unknown. Larger studies are needed to determine whether HITS are a marker of risk of neurologic injury from emboli during pediatric cardiac catheterization.

A Review of the Effectiveness of Neuroimaging Modalities for the Detection of Traumatic Brain Injury.

The incidence of traumatic brain injury (TBI) in the United States was 3.5 million cases in 2009, according to the Centers for Disease Control and Prevention. It is a contributing factor in 30.5% of injury-related deaths among civilians. Additionally, since 2000, more than 260,000 service members were diagnosed with TBI, with the vast majority classified as mild or concussive (76%). The objective assessment of TBI via imaging is a critical research gap, both in the military and civilian communities. In 2011, the Department of Defense (DoD) prepared a congressional report summarizing the effectiveness of seven neuroimaging modalities (computed tomography [CT], magnetic resonance imaging [MRI], transcranial Doppler [TCD], positron emission tomography, single photon emission computed tomography, electrophysiologic techniques [magnetoencephalography and electroencephalography], and functional near-infrared spectroscopy) to assess the spectrum of TBI from concussion to coma. For this report, neuroimaging experts identified the most relevant peer-reviewed publications and assessed the quality of the literature for each of these imaging technique in the clinical and research settings. Although CT, MRI, and TCD were determined to be the most useful modalities in the clinical setting, no single imaging modality proved sufficient for all patients due to the heterogeneity of TBI. All imaging modalities reviewed demonstrated the potential to emerge as part of future clinical care. This paper describes and updates the results of the DoD report and also expands on the use of angiography in patients with TBI.

Use of Transcranial Doppler (TCD) ultrasound in the Neurocritical Care Unit.

Transcranial Doppler (TCD) is a portable device that uses a handheld 2-MHz transducer. It is most commonly used in subarachnoid hemorrhage where cerebral blood flow velocities in major intracranial blood vessels are measured to detect vasospasm in the first 2 to 3 weeks. TCD is used to detect vasospasm in traumatic brain injury and post-tumor resection, measurement of cerebral autoregulation and cerebrovascular reactivity, diagnosis of acute arterial occlusions in stroke, screening for patent foramen ovale and monitoring of emboli. It can be used to detect abnormally high intracranial pressure and for confirmation of total cerebral circulatory arrest in brain death.

Cerebral hemodynamic changes after wartime traumatic brain injury.

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

American Society of Neurophysiologic Monitoring and American Society of Neuroimaging joint guidelines for transcranial doppler ultrasonic monitoring.

The American Society of Neurophysiologic Monitoring (ASNM) and American Society of Neuroimaging (ASN) Guidelines Committees formed a joint task force and developed guidelines to assist in the use of transcranial Doppler (TCD) monitoring in the surgical and intensive care settings. Specifically, these guidelines: (1) delineate the objectives of TCD monitoring; (2) characterize the responsibilities and behaviors of the sonographer during monitoring; (3) describe methodological and ethical issues uniquely relevant to monitoring. The ASNM and ASN strongly support the positions that (1) acquisition and interpretation of intraoperative TCD ultrasonograms be performed by qualified individuals, (2) service providers define their diagnostic criteria and develop on-going self-validation programs of these performance criteria in their practices. We agree with the guidelines of other professional societies regarding the technical and professional qualifications of individuals responsible for TCD signal acquisition and interpretation (Class III evidence, Type C recommendation). On the basis of current clinical literature and scientific evidence, TCD monitoring is an established monitoring modality for the: (1) assessment of cerebral vasomotor reactivity and autoregulation; (2) documentation of the circle of Willis functional status; (3) identification of cerebral hypo- and hyperperfusion, recanalization and re-occlusion; and (4) detection of cerebral emboli (Class II and III evidence, Type B recommendation).

Transcranial Doppler ultrasonography identifies symptomatic cavum septum pellucidum cyst: case report.

OBJECTIVE: Cavum Septum Pellucidum (CSP) cysts are considered normal anatomic variants, comprising as many as 15% of the adult and 85% of pediatric populations. On rare occasions, the cavum can obstruct CSF outflow from the lateral ventricles causing elevated intracranial pressure (ICP) and headaches. The purpose of this paper is to present a challenging case of new onset symptomatic CSP in a previously healthy adult male without papilledema and elevated ICP detected by transcranial Doppler (TCD) ultrasonography. CLINICAL PRESENTATION: A previously healthy 44 year-old man presented to the neurology service with debilitating positional headaches that were mitigated solely by recumbent positioning. A magnetic resonance imaging scan (MRI) of the brain revealed a cavum septum pellucidum. A lumbar puncture was performed and revealed normal ICP. No papilledema was evident on fundoscopic examination. A CSF flow study revealed normal dye opacification pattern without evidence of CSF leak. INTERVENTION: Without other clinical indicators of high ICP, but a history suspicious for symptomatic CSP, TCD study was performed and revealed abnormally low cerebral blood flow velocities (CBFV's) and significantly elevated pulsatility indices (PI's) for patient's age indicative of high ICP. Endoscopic fenestration of the septum pellucidum was performed improving the patient's headaches and normalization of the PI's and CBFV's to normal (p<0.01). CONCLUSIONS: Symptomatic CSP is a difficult diagnosis to make based on existing diagnostic paradigm. TCD in the absence of other objective confirmatory studies, can aid in the diagnosis and provide information about the success of fenestration of the cavum septum.

High prevalence of right-to-left shunt in patients with symptomatic great saphenous incompetence and varicose veins.

BACKGROUND: Varicose veins are common and increasingly are being treated by less invasive endoscopic methods such as foam sclerotherapy. Patent foramen ovale (PFO) is also common, present in approximately one-quarter of adults. PFO allows bubbles introduced by foam sclerotherapy to cross into the general circulation, potentially causing cerebral artery gas embolization with unevaluated consequences. METHODS: Men and women aged 18 to 60 years with symptomatic varicose veins (CEAP C(3-5)) responded to an advertisement to recruit volunteers for a study on endovenous microfoam ablation (EMA). Participants' veins were screened by duplex ultrasound imaging, and those with isolated great saphenous vein (GSV) incompetence were tested for right-to-left (R-L) vascular shunt using transcranial Doppler (TCD) of the middle cerebral artery to detect the presence of bubble emboli after an injection of an agitated saline, blood, and air mixture as a contrast at rest and with the Valsalva maneuver. RESULTS: Of 221 participants tested for R-L shunt, 85 (38.5%) were positive at rest (95% confidence interval [CI], 32.5-45.2) and 114 (51.8%) were positive after the Valsalva maneuver (95% CI, 45.4-58.5). A total 130 patients (58.8%) were positive for R-L shunt at rest or after Valsalva (95% CI, 52.5%-65.1%). This is significantly higher than the reported 26% prevalence of PFO in the general population (95% CI, 24.4-30.1). CONCLUSIONS: The prevalence of R-L shunt in patients with GSV incompetence CEAP C(3-5) in this study was higher than expected in the general population. TCD does not differentiate between intracardiac shunts and intrapulmonary shunts, so this observation needs further investigation. This link between R-L shunt and varicose veins is novel and, whether etiologic or functional, may improve the understanding of both conditions. The findings have importance in the treatment of varicose veins with foam sclerotherapy and EMA.

Practice standards for transcranial Doppler ultrasound: part I--test performance.

Indications for the clinical use of transcranial Doppler (TCD) continue to expand while scanning protocols and quality of reporting vary between institutions. Based on literature analysis and extensive personal experience, an international expert panel started the development of guidelines for TCD performance, interpretation, and competence. The first part describes complete diagnostic spectral TCD examination for patients with cerebrovascular diseases. Cranial temporal bone windows are used for the detection of the middle cerebral arteries (MCA), anterior cerebral arteries (ACA), posterior cerebral arteries (PCA), C1 segment of the internal carotid arteries (ICA), and collateralization of flow via the anterior (AComA) and posterior (PComA) communicating arteries; orbital windows-for the ophthalmic artery (OA) and ICA siphon; the foraminal window-for the terminal vertebral (VA) and basilar (BA) arteries. Although there is a significant individual variability of the circle of Willis with and without disease, the complete diagnostic TCD examination should include bilateral assessment of the M2 (arbitrarily located at 30-40 mm depth), M1 (40-65 mm) MCA [with M1 MCA mid-point at 50 mm (range 45-55 mm), average length 16 mm (range 5-24 mm), A1 ACA (60-75 mm), C1 ICA (60-70 mm), P1-P2 PCA (average depth 63 mm (range 55-75 mm), AComA (70-80 mm), PComA (58-65 mm), OA (40-50 mm), ICA siphons (55-65 mm), terminal VA (40-75 mm), proximal (75-80), mid (80-90 mm), and distal (90-110 mm) BA]. The distal ICA on the neck (40-60 mm) can be located via submandibular windows to calculate the VMCA/VICA index, or the Lindegaard ratio for vasospasm grading after subarachnoid hemorrhage. Performance goals of diagnostic TCD are to detect and optimize arterial segment-specific spectral waveforms, determine flow direction, measure cerebral blood flow velocities and flow pulsatility in the above-mentioned arteries. These practice standards will assist laboratory accreditation processes by providing a standard scanning protocol with transducer positioning and orientation, depth selection and vessel identification for ultrasound devices equipped with spectral Doppler and power motion Doppler.

Inverse correlation between cerebral blood flow measured by continuous arterial spin-labeling (CASL) MRI and neurocognitive function in children with sickle cell anemia (SCA).

Overt stroke, clinically "silent" cerebral infarct, and neurocognitive impairment are frequent complications of sickle cell anemia (SCA). Current imaging techniques have limited sensitivity and specificity to identify children at risk for neurocognitive impairment. We prospectively evaluated 24 children with SCA with a neurologic exam, complete blood count, transcranial Doppler ultrasound (TCD), measurement of intelligence quotient (IQ), and magnetic resonance imaging (MRI) with measurement of cerebral blood flow (CBF) using continuous arterial spin-labeling (CASL) MRI. Average CBF to gray matter was 112 +/- 36 mL/100 g/min. We identified a strong inverse relationship between performance IQ and CBF (-1.5 points per 10 mL/100 g/min increase in CBF, P = .013). Elevated steady-state white blood cell count (> or = 14 x 10(9)/L [14,000/microL]) was associated with lower full scale IQ (86 +/- 9 vs 99 +/- 10, P = .005). CASL MRI may identify children with neurocognitive impairment, before damage is evident by structural MRI or TCD.

Advanced neurologic monitoring for cardiac surgery.

Cardiac surgery (CS) with cardiopulmonary bypass (CPB) is currently the most common surgery in the United States. Understanding, avoiding, and preventing postoperative complications, including neurologic deficits following CS, represents a great public and economic benefit for society, especially considering our aging population. There is a critical need to identify new strategies that will prevent harmful events during and after CS. At present, experience with neurophysiologic techniques includes the ability to measure cerebral blood flow velocity/emboli and regional cerebral venous oxygen saturation by transcranial Doppler ultrasound, and by near-infrared spectroscopy, respectively. Continuous monitoring of these variables along with systemic hemodynamics will provide a better understanding of mechanisms of brain and other organ injury during CPB. Neuroprotective interventions based on multimodality neurologic monitoring would ideally eliminate postoperative complications and improve patient outcomes.

Quantitation of contrast TCD in patients with and without atrial septal aneurysm.

BACKGROUND AND PURPOSE: Patients with a combination of atrial septal aneurysm (ASA) and patent foramen ovale (PFO) have a substantially higher rate of recurrent ischemic events as compared to PFO alone. One possible explanation is a greater degree of right-to-left shunting with the combination. METHODS: Retrospective study using contrast transcranial Doppler ultrasonography (c-TCD) to study the degree of shunting in 46 patients with PFO with either transient ischemic attack or cryptogenic ischemic stroke. Eight patients with PFO+ASA identified on transesophageal echocardiogram were compared to 38 patients with PFO but without ASA. RESULTS: The number of embolic counts was no different with or without an ASA. Valsalva maneuver increased number of emboli, especially in patients with large PFOs. CONCLUSIONS: Patients with ASA in addition to PFO do not appear to have an increased risk of right-to-left shunting as measured by c-TCD as compared to PFO alone.

Differentiating vascular pathophysiological states by objective analysis of flow dynamics.

BACKGROUND AND PURPOSE: There is an unmet need to classify cerebrovascular conditions physiologically and to assess cerebrovascular system performance. The authors hypothesized that by simultaneously considering the dynamic parameters of flow velocity, acceleration, and pulsatility index (PI) (impedance) in individual Doppler spectrum waveforms, they could develop an objective method to elucidate the pathophysiology of vascular conditions and classify cerebrovascular disorders. This method, dynamic vascular analysis (DVA), is described. METHODS: First, a theoretical model was developed to determine how any vascular segment and the ensemble of intracranial vascular segments could be defined according to its dynamic physiological characteristics. Next, the DVA method was applied to 847 anonymous serial complete clinical transcranial Doppler (TCD) studies of patients without regard for their diagnosis to ascertain actual reference ranges and the normality of the distribution curves for each dimension of the 3-parameter nomogram. The authors applied DVA to 2 clinical cases to see if they could track the changes in vascular performance of 2 known progressive diseases. RESULTS: The theoretical analysis identified 295,245 possible vascular states for the ensemble of vascular segments in the cerebral circulation. When applied to clinical TCD data, DVA revealed continuous, normally distributed data for the velocity, PI, and logarithm of the acceleration. CONCLUSIONS: DVA is proposed as a method for monitoring the physiological state of each cerebral artery segment individually and in ensemble. DVA evaluates the relationship among acceleration (force or pressure), velocity, and PI and provides an objective means to evaluate intracranial vascular segments using the paradigm of the well-described pressure-perfusion autoregulation relationship. DVA may be used to study cerebrovascular pathophysiology and to classify, evaluate, and monitor cerebrovascular disorders or systemic disorders with cerebrovascular effects.

Biphasic cerebral blood flow velocity profile in patients with aneurysmal subarachnoid hemorrhage.

INTRODUCTION: Increases in cerebral blood flow velocity (CBFV) as measured by transcranial Doppler (TCD) sonography are reflective of cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage (SAH). In serial TCD measurements, some patients exhibit CBFV temporal profiles with two peaks (biphasic). The significance of this finding remains unclear. This retrospective case-control study was conducted to investigate the characteristics and possible predictors of biphasic CBFV profiles. METHODS: Biphasic CBFV profiles were identified in serial TCD examinations (every 1-2 days) of 182 consecutive patients admitted for aneurysmal SAH based on CBFV profiles of the middle cerebral artery on the side of higher maximum velocity. Patients undergoing angioplasty were excluded. Patients meeting these criteria (study patients) were compared to control patients matched for age and Hunt and Hess grade. RESULTS: Eighteen patients (9.9%) demonstrated biphasic CBFV profiles. The first CBFV (134 +/- 11 cm/second) peak occurred on post-SAH day 6 +/- 1, and the second peak (148 +/- 12 cm/second) on day 13 +/- 1. Study patients more often exhibited focal (p < 0.05) symptoms at the time of the first peak. No patient deteriorated neurologically at the time of the second peak. No correlation was observed between CBVF and mean arterial pressure or central venous pressure trends. CONCLUSION: Serial TCD assessment identifies patients with SAH and a biphasic CBFV temporal profile. Although the second peak usually is not associated with a worsening of symptoms, these patients were more likely to exhibit clinical symptoms during the first CBFV peak.