Prehospital clinical signs are a poor predictor of raised intracranial pressure following traumatic brain injury

ter Avest, Ewoud, Taylor, Sam, Wilson, Mark and Lyon, Richard L (2020) Prehospital clinical signs are a poor predictor of raised intracranial pressure following traumatic brain injury Emergency Medicine Journal.

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Abstract

Background

For the prehospital diagnosis of raised intracranial pressure (ICP), clinicians are reliant on clinical signs such as the Glasgow Coma Score (GCS), pupillary response and/or Cushing’s triad (hypertension, bradycardia and an irregular breathing pattern). This study aimed to explore the diagnostic accuracy of these signs as indicators of a raised ICP.

Methods

We performed a retrospective cohort study of adult patients attended by a Helicopter Emergency Medical Service (Air Ambulance Kent, Surrey Sussex), who had sustained a traumatic brain injury (TBI), requiring prehospital anaesthesia between 1 January 2016 and 1 January 2018. We established optimal cut-off values for clinical signs to identify patients with a raised ICP and investigated diagnostic accuracy for combinations of these values.

Results

Outcome data for 249 patients with TBI were available, of which 87 (35%) had a raised ICP. Optimal cut-off points for systolic blood pressure (SBP), heart rate (HR) and pupil diameter to discriminate patients with a raised ICP were, respectively, ˃160 mm Hg,˂60 bpm and ˃5 mm. Cushing criteria (SBP ˃160 mm Hg and HR ˂60 bpm) and pupillary response and size were complimentary in their ability to detect patients with a raised ICP. The presence of a fixed blown pupil or a Cushing’s response had a specificity of 93.2 (88.2–96.6)%, and a positive likelihood ratio (LR+) of 5.4 (2.9–10.2), whereas sensitivity and LR− were only 36.8 (26.7–47.8)% and 0.7 (0.6–0.8), respectively, (Area Under the Curve (AUC) 0.65 (0.57–0.73)). Sensitivity analysis revealed that optimal cut-off values and resultant accuracy were dependent on injury pattern.

Conclusion

Traditional clinical signs of raised ICP may under triage patients to prehospital treatment with hyperosmolar drugs. Further research should identify more accurate clinical signs or alternative non-invasive diagnostic aids in the prehospital environment.

Item Type:	Article
Divisions :	Faculty of Health and Medical Sciences > School of Health Sciences
Authors :	Name Email ORCID ter Avest, Ewoud Taylor, Sam Wilson, Mark Lyon, Richard L r.lyon@surrey.ac.uk
Date :	18 September 2020
DOI :	10.1136/emermed-2020-209635
Copyright Disclaimer :	© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
Uncontrolled Keywords :	Prehospital; Clinical signs; Brain herniation; Intracranial pressure (ICP); Hypertonic Saline (HS)
Depositing User :	Clive Harris
Date Deposited :	06 Oct 2020 16:17
Last Modified :	06 Oct 2020 16:17
URI:	http://epubs.surrey.ac.uk/id/eprint/858679

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