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. J Neurol Res. 2020;10(5):177-182 doi: https://doi.org/10.14740/jnr611