Impact of Cervical Collar and Patient Position on the Cerebral Blood Flow

Abstract

Background: Spinal protection during emergency medical service (EMS) transport after trauma has become a focus of debate. Historically, patients at risk for spine injury are transported in a rigid collar, long spineboard and headblocks. The cervical collar (c-collar) is hypothesized to provide stabilization for the cervical spine. However, little is known how the c-collar affects cervical blood flow.Methods: Cerebral blood flow was measured in multiple conditions using a non-invasive cerebral blood flow monitor to establish cerebral blood flow index (CBFI). The CBFI data were collected at: standing, sitting, 45°, 30°, 10° or 15°, and supine, with and without c-collar. Descriptive statistics were used for CBFI in each condition, and parametric statistical methods were utilized to determine the significance of changes in CBFI.Results: Five volunteers were recruited, and each tested in six positions with and without c-collar. Mean age was 49 (standard deviation (SD) 15) years and 60% were male. The CBFI mean of means was 71.0 with and 69.4 without the c-collar. Only one subject demonstrated a statistically significant difference in CBFI with c-collar. The CBFI mean of means for position was 72.6 for head of bed less than 30° and 68.1 for greater than 30°. All subjects demonstrated > 99% confidence for a statistically significant difference in CBFI when dichotomized using head of bed at 30°. Conclusions:Head of the bed position has greater influence on CBFI than the c-collar . Clinical significance in healthy volunteers is unknown but this change in cerebral blood flow may have clinical significance in traumatic brain injury or neurologic conditions that compromise autoregulation.

The Impact of a Cervical Collar on Intracranial Pressure in Traumatic Brain Injury Patients: A Systematic Review and Meta-Analysis

“…An example of a cervical collar utilized by emergency medical services (EMS) is the Laerdal Stifneck [10]. Globally, most ambulance services use the Laerdal Stifneck collar (Life-Assist, Inc., Rancho Cordova, CA, USA), which is one of the most universally used collars for this purpose in a prehospital setting [11][12][13]. However, spinal collars must be fitted properly and adjusted for height, level of fitness and should not interfere with the blood flow into or from the brain [13].…”