title: Head position and cerebral blood flow in acute ischemic stroke patients: Protocol for the pilot phase, cluster randomized, Head Position in Acute Ischemic Stroke Trial (HeadPoST pilot).
abstract: BACKGROUND
  Few proven interventions exist for acute ischemic stroke (AIS), and most are expensive and restricted in applicability. Lying flat 'head down' positioning of AIS patients has been shown to increase by as much as 20%, mean cerebral blood flow velocities (CBFV) measured by transcranial Doppler (TCD) but whether this translates into clinical improvement is uncertain.
  
  
  OBJECTIVE
  To determine if the lying flat position increases mean CBFV in the affected territory as compared to the sitting up position in AIS patients.
  
  
  METHODS
  Head Position in Acute Ischemic Stroke Trial (HeadPoST pilot) is a cluster randomized (clusters being months), assessor-blinded end-point, phase IIb trial, where consecutive adults with anterior circulation AIS within 12 h of symptom onset are positioned to a randomized position for 48 h with TCD performed serially.
  
  
  RESULTS
  Primary outcome is mean CBFV on TCD at 1 and 24 h after positioning. Secondary outcomes include: serious adverse events, neurological impairment at seven days, and death and disability at 90 days.
  Assuming an increase of 8.3 (SD 11.4) cm/s in average of mean CBFV when tilted from 30° to 0°, 46 clusters are required (92 patients in total) to detect a 20% increase of mean CBFV with 90% power and 5% level of significance.
  
  
  CONCLUSIONS
  HeadPoST pilot is a cluster randomized multicenter clinical trial investigating the effect of head positioning on mean CBFV in anterior circulation AIS.
authors.affiliation: Vascular Neurology Program, Neurology Service, Department of Internal Medicine, Clínica Alemana de Santiago, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile.
authors.forename: Alejandro M
authors.initials: AM
authors.lastname: Brunser
authors.affiliation: Vascular Neurology Program, Neurology Service, Department of Internal Medicine, Clínica Alemana de Santiago, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile The George Institute for Global Health, University of Sydney and Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.
authors.forename: Paula
authors.initials: P
authors.lastname: Muñoz Venturelli
authors.affiliation: Vascular Neurology Program, Neurology Service, Department of Internal Medicine, Clínica Alemana de Santiago, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile Department of Neurological Sciences, Universidad de Chile, Santiago, Chile.
authors.forename: Pablo M
authors.initials: PM
authors.lastname: Lavados
authors.affiliation: Servicio de Neurología, Hospital Clínico Dr. Lautaro Navarro Avaria, Punta Arenas, Chile.
authors.forename: Javier
authors.initials: J
authors.lastname: Gaete
authors.affiliation: Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brasil.
authors.forename: Sheila
authors.initials: S
authors.lastname: Martins
authors.affiliation: The George Institute for Global Health, University of Sydney and Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.
authors.forename: Hisatomi
authors.initials: H
authors.lastname: Arima
authors.affiliation: The George Institute for Global Health, University of Sydney and Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.
authors.forename: Craig S
authors.initials: CS
authors.lastname: Anderson
authors.affiliation: Vascular Neurology Program, Neurology Service, Department of Internal Medicine, Clínica Alemana de Santiago, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile veroolavarria@yahoo.com.
authors.forename: Verónica V
authors.initials: VV
authors.lastname: Olavarría
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002985:Clinical Protocols / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D010865:Pilot Projects; D016684:Prone Position / Q000502:physiology*; D020521:Stroke / Q000503:physiopathology* / Q000628:therapy*; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial
keywords: Ischemic stroke; blood flow velocity; head position; middle cerebral artery; pilot trial; transcranial Doppler