Practice Recommendations for Transcranial Doppler Ultrasonography in Critically Ill Children in the Pediatric Intensive Care Unit: A Multidisciplinary Expert Consensus Statement.

Transcranial Doppler ultrasonography (TCD) is being used in many pediatric intensive care units (PICUs) to aid in the diagnosis and monitoring of children with known or suspected pathophysiological changes to cerebral hemodynamics. Standardized approaches to scanning protocols, interpretation, and documentation of TCD examinations in this setting are lacking. A panel of multidisciplinary clinicians with expertise in the use of TCD in the PICU undertook a three-round modified Delphi process to reach unanimous agreement on 34 statements and then create practice recommendations for TCD use in the PICU. Use of these recommendations will help to ensure that high quality TCD images are captured, interpreted, and reported using standard nomenclature. Furthermore, use will aid in ensuring reproducible and meaningful study results between TCD practitioners and across PICUs.

Transcranial Doppler Ultrasonographic Evaluation of Cerebrovascular Abnormalities in Children With Acute Bacterial Meningitis.

Introduction: Bacterial meningitis (BM) is a global public health concern that results in significant morbidity and mortality. Cerebral arterial narrowing contributes to stroke in BM and may be amenable to intervention. However, it is difficult to diagnose in resource-limited settings where the disease is common. Methods: This was a prospective observational study from September 2015 to December 2019 in sub-Saharan Africa. Children 1 month-18 years of age with neutrophilic pleocytosis or a bacterial pathogen identified in the cerebrospinal fluid were enrolled. Transcranial Doppler ultrasound (TCD) of the middle cerebral arteries was performed daily with the aim to identify flow abnormalities consistent with vascular narrowing. Results: Forty-seven patients were analyzed. The majority had Streptococcus pneumoniae (36%) or Neisseria meningitides (36%) meningitis. Admission TCD was normal in 10 (21%). High flow with a normal pulsatility index (PI) was seen in 20 (43%) and high flow with a low PI was identified in 7 (15%). Ten (21%) had low flow. All children with a normal TCD had a good outcome. Patients with a high-risk TCD flow pattern (high flow/low PI or low flow) were more likely to have a poor outcome (82 vs. 38%, p = 0.001). Conclusions: Abnormal TCD flow patterns were common in children with BM and identified those at high risk of poor neurological outcome.

Transcranial Doppler Ultrasonography Provides Insights into Neurovascular Changes in Children with Cerebral Malaria.

OBJECTIVE: To evaluate neurovascular changes in pediatric patients with cerebral malaria. STUDY DESIGN: African children with cerebral malaria were enrolled and underwent daily transcranial Doppler ultrasound (TCD) examinations through hospital day 8, discharge, or death. Neurologic outcomes were assessed 2 weeks after enrollment. RESULTS: In total, 160 children with cerebral malaria and 155 comparison patients were included. In patients with cerebral malaria, TCD flow changes characterized as hyperemia were seen in 42 (26%), low flow in 46 (28%), microvascular obstruction in 35 (22%), cerebral vasospasm in 21 (13%), and isolated posterior hyperemia in 7 (4%). Most had a single neurovascular phenotype observed throughout participation. Among comparison patients, 76% had normal TCD findings (P < .001). Impaired autoregulation was present in 80% of cases (transient hyperemic response ratio 1.01 ± 0.03) but improved through day 4 (1.1 ± 0.02, P = .014). Overall mortality was 24% (n = 39). Neurologic deficits were evident in 21% of survivors. Children meeting criteria for vasospasm were most likely to survive with sequelae, and children meeting criteria for low flow were most likely to die. Autoregulation was better in children with a normal neurologic outcome (1.09, 95% CI 1.06-1.12) than in others (0.98, 95% CI 0.95-1) (P ≤ .001). CONCLUSIONS: Several distinct changes in TCD measurements were identified in children with cerebral malaria that permitted phenotypic grouping. Groups had distinct associations with neurologic outcomes. Validation of pathogenic mechanisms associated with each phenotype may aid in developing TCD as a portable, easy-to-use tool to help guide targeted adjunctive therapy in cerebral malaria aimed at causative mechanisms of injury on an individual level.

Relationships between cerebral flow velocities and neurodevelopmental outcomes in children with moderate to severe traumatic brain injury.

PURPOSE: This study aimed to determine relationships between cerebral blood flow and neurodevelopmental outcomes in children with moderate to severe traumatic brain injury (TBI). METHODS: Children with TBI, a Glasgow Coma Score of 8-12, and abnormal brain imaging were enrolled prospectively. Cerebral blood flow velocity (CBFV) was assessed within 24 h of trauma and daily thereafter through death, discharge, or hospital day 8, whichever came first. Twelve months from injury, participants completed neurodevelopmental testing. RESULTS: Sixty-nine patients were enrolled. Low flow velocities (< 2 SD below age/gender normal) were found in 6% (n = 4). No patient with a single low CBFV measurement had a good neurologic outcome (Pediatric Glasgow Outcome Scale (GOS-E Peds) ≤ 4)). Normal flow velocities (± 2 SD around age/gender normal) were seen in 43% of participants (n = 30). High flow velocities (> 2 SD above age and gender normal with a Lindegaard ratio (LR) < 3) were identified in 23% of children (n = 16), and vasospasm (> 2 SD above age/gender normal with LR ≥ 3) was identified in 28% (n = 19). Children with good outcomes based on GOS-E Peds scoring were more likely to have had normal flow velocity than other flow patterns. No other differences in neurodevelopmental outcomes were noted. CONCLUSIONS: Individual patient responses to TBI in terms of CBFV alterations were heterogeneous. Low flow was uniformly associated with a poor outcome. Patients with good outcomes were more likely to have normal flow. This suggests CBFV may serve as a prognostic indicator in children with TBI. Future studies are needed to determine if aberrant CBFVs are also a therapeutic target.

Reference values for cerebral blood flow velocities in critically ill, sedated children.

OBJECTIVE: Transcranial Doppler ultrasound (TCD) is increasingly being used in the pediatric intensive care unit to assess cerebral hemodynamics during critical illness. However, no normative data in this patient population have been published to date. Therefore, we aimed to describe the anterior and posterior cerebral blood flow velocities in critically ill children undergoing mechanical ventilation and sedation. DESIGN: A prospective, observational cohort study was performed. Children with known or suspected acute or chronic neurologic conditions were excluded. Participants underwent TCD measurement of middle cerebral and basilar artery flow velocities. RESULTS: One hundred and forty children newborn to 17 years of age were enrolled. Measured values were lower in this cohort of children than the previously published cerebral flow velocities of normal, healthy children. CONCLUSIONS: Cerebral blood flow velocities of the basal cerebral arteries in critically ill, mechanically ventilated, sedated children are lower than in healthy children of the same age and gender published in previous studies. As such, the cerebral blood flow velocity (CBFV) values reported here may serve as a more accurate reference point when using TCD as a clinical tool to diagnose CBFV abnormalities and guide therapy in this patient population.

Vasospasm in children with traumatic brain injury.

OBJECTIVE: To determine the incidence of vasospasm in children who have suffered moderate to severe traumatic brain injury. METHODS: A prospective observational pilot study in a 24-bed pediatric intensive care unit was performed. Twenty-two children aged 7 months to 14 years with moderate to severe traumatic brain injury as indicated by Glasgow Coma Score 120 cm/s were considered to have vasospasm by criterion A. If flow velocity in the MCA was >120 cm/s and the Lindegaard ratio was >3, vasospasm was considered to be present by criterion B. Patients with basilar artery (BA) flow velocity >90 cm/s met criteria for vasospasm in the posterior circulation (criterion C). RESULTS: In the MCA, 45.5% of patients developed vasospasm based on criterion A and 36.3% developed vasospasm based on criterion B. A total of 18.2% of patients developed vasospasm in the BA by criterion C. Typical day of onset of vasospasm was hospital day 2-3. Duration of vasospasm in the anterior circulation was 4 +/- 2 days based on criteria A and 3 +/- 1 days based on criteria B. Vasospasm in the posterior circulation persisted for 2 +/- 1 days. CONCLUSIONS: Using the adult criteria outlined above to diagnose vasospasm, a significant proportion of pediatric patients who have suffered moderate to severe traumatic brain injury develop vasospasm during the course of their treatment.