To what extent are GCS and AVPU equivalent to each other when assessing the level of consciousness of children with head injury? A cross-sectional study of UK hospital admissions. (2024)

Associated Data

Supplementary Materials

Abstract

Keywords: GCS, Glasgow Coma Score, AVPU, head injury

Introduction

An estimated 30 000 children are admitted to hospitals in England annually with head injury.¹ Although the majority of injuries are mild with a low mortality rate (<0.5%), an estimated 15%–20% have moderate to severe traumatic brain injury.² Children with impaired levels of consciousness have the greatest risk of significant morbidity or mortality.^{2 3} Clinicians rely on scores, such as the Glasgow Coma Scale (GCS) to evaluate levels of consciousness to identify children who need further investigation and early intervention.⁴

Teasdale and Jennet devised the GCS in 1974 (modified in 1976)^{4 5} (online supplementary table 1). It scores levels of neurological dysfunction in three components; motor, verbal and eye opening responses that are considered separately and combined into an overall score. Evaluating levels of consciousness in young children is challenging due to their limited verbal and motor responses, and several adaptations to the GCS for <5 years olds have been proposed.⁶ UK head injury guidelines recommend the paediatric GCS (pGCS) for infants <1 year old.^{3 7}

National Institute for Health and Care Excellence (NICE) guidelines from 2003 to 2014 recommend that all children with a head injury have a GCS recorded at prehospital assessment and when seen in emergency departments (ED), that infants have a CT scan when GCS is <15 and for the older children CT is recommended when GCS<14³ Ambulance staff, ED and child health clinicians receive regular updated training in its application. The score provides a baseline to facilitate triage, monitor levels of consciousness and aid decisions about whether CT imaging is required, the level of care and need for specialist involvement. However, studies have identified high levels of inter-rater variability, and variability in outcome prediction based on GCS.^{8 9}

The complexity of the GCS compared with other simpler scores raises concerns about its utility¹⁰ and alternative shorter scores are used. The AVPU score (online supplementary table 1) was introduced by the American College of Surgeons¹¹ to monitor the patients with poisoning.¹² It is less detailed and has four broad scores, A, Alert; V, responsive to Verbal stimulus; P, responsive to Painful stimulus; U, Unresponsive. No formal training is required to administer this score and it can be used easily at the site of injury.¹³

The Confidential Enquiry into Head Injury in Childhood was the principal project within the Centre for Maternal and Child Enquires (CMACE) collected data from hospital admissions for head injury across the UK. This large dataset provided the opportunity to evaluate the clinical practice of recording levels of consciousness for children with head injury.

This study aims to describe the utilisation of GCS and AVPU in children with head injury, to determine the correlation between AVPU and GCS scores for children older and those younger than 5 years of age and to explore whether the scoring system that is used to measure of level of consciousness affects the rate of CT scan and subsequent diagnostic yield.

Methods

Data were collected from the case notes of children up to 15 years of age admitted to hospital for more than 4 hours following a head injury between September 2009 and February 2010. Ninety per cent of hospitals that admit children for head injury in England, Wales, Northern Ireland and the Channel islands participated in the study.¹⁴ Children with superficial or facial injuries that were unlikely to be associated with brain injury were excluded. The data collection proformas were designed to follow the child’s pathway of care and to obtain information that was available from the child’s hospital records. Proformas (online supplementary figure 1a,b) were completed by local head injury enquiry coordinators (previously identified in each hospital) and entered onto a secure CMACE database and placed in SPSS Statistics V.19 for analysis.

Data were collected for each child for GCS total and component scores, AVPU score, age, the type of hospital to which the child was admitted (specialist hospitals were defined as designated children’s hospital, or those that became major trauma centres in 2012 and general hospitals, were those that had none of these facilities), whether or not the children received a CT scan and the diagnostic yield of intracranial abnormality or depressed fracture.

Results

Overall, 5700 children were included in the study, median age 49 months, 61.4% (3500) were boys (online supplementary figure 2), 1801 children were transported to hospital by ambulance and 385 were transferred on to a second hospital (data were available for 318 of these latter cases).

Overall 90.6% (5168/5700) of children had their consciousness level recorded in the ED at the first hospital to which they were admitted, as did 85% (271/318) of children who were transferred to a second hospital, 66.1% (1190/1801) of the children transported to hospital by ambulance had their consciousness level recorded at the scene of the incident (table 1).

The proportion of children who had an ‘AVPU only’ or no recording was higher for younger children and decreased with age, whereas the proportion of children who had a ‘GCS only’ increased with the age (figure 1). Overall 73.5% (4426/6018) of child hospital attendances had a GCS recorded. Of the total 5487 GCS recorded only 75.4% (4137) had the component scores documented.

Children were first taken to a general hospital in 83.6% (4768) of cases, and specialist hospitals in the remainder. The specialist hospitals recorded an APVU in significantly fewer cases than the general hospitals (13.6%: 95% CI 11.6% to 16.0% vs 18%: 95% CI 16.9% to 19.1%) (figure 1).

Discussion

The consciousness level was documented in 90% of children admitted to hospital with head injury. Overall the majority of hospital and prehospital admissions had a GCS recorded. While this is in keeping with current NICE guidelines,³ it was not universal practice and 30% of assessments reported in this study used either AVPU only or had no measure of conscious state recorded. The AVPU was most frequently used for infants <1 year old, while the GCS was used more frequently in older children. This finding is likely to be due to difficulties applying the GCS in infancy, despite the pGCS that is designed to account for these limitations.

The use of the ‘AVPU only’ in infancy (<1 year) did not adversely affect the clinical management or diagnosis in terms of the proportion of children who had CT head scans undertaken and the diagnostic yield. Indeed, it could be argued that the AVPU=V/P/U was a more specific measure of serious head injury in this age group, as a significantly greater proportion of the children with a recorded AVPU=V/P/U had an ICI or a depressed fracture on CT scan when compared with cases where ‘GCS only’ was applied. However, among older children the GCS was a better predictor of an abnormal CT as in those with a GCS<14, significantly more children had a CT scan and significantly more of these scans were abnormal than when V/P/U only was recorded. The level of consciousness is not the only factor to influence the decision to undertake a CT scan.³ This study confirms that an estimated 1 in 5–10 children with no impaired consciousness had an abnormality on CT. Influential factors for the same series of children are described further in Kemp et al.¹⁶ However, these results would support the inclusion of AVPU as an acceptable initial measure of level of consciousness in infants and support a recommendation that a CT scan should be undertaken if AVPU=V/P/U.

The AVPU is simple, but none of the components are clearly defined. When considering the theoretical equivalence of AVPU to the components of the GCS, there is a range of total GCS that could be equivalent to each AVPU component. The definitions of eye opening scores (E1-4) can be directly related to the AVPU responses. However, an Alert child could be equivalent to a GCS of 15 or 14 as they may be Alert but confused and have a verbal score of V4, however a verbal response would only be detectable in >5 year where the unmodified GCS is advised. An Unresponsive child should score an E1 and V1, however the motor response may include M3 as they may be decorticate or decerebrate. Therefore, the theoretical range for U could be a GCS 3–5.

It is less easy to align Verbal or Pain responsive categories of AVPU to GCS component scores due in part to the difference in pGCS and adult GCS. While the GCS component descriptors for the <5 year olds are more specific than for the older age group in terms of responsiveness there is still considerable scope for matching against different scores. For example, a child <5 years who responds to pain may score E2 for eye opening, V2-V3 for a verbal score and M2-5 for motor, that is, a total score between 6 and 10 while for a child >5 years the corresponding scores could be E2, V2-V5, M2-M5 totalling a score between 6 and 12. These wide ranges are reflected in the study results. Due to the large variability of V/P on the GCS, the AVPU is not sufficiently precise to closely monitor neurological deterioration.

Table 4 lists published studies that compare GCS with AVPU scores. The majority support a clear correlation between Alert and GCS=15 and Unresponsive with GCS=3 with a wider range of associated GCS scores for responsive to Pain or Voice. There are only two smaller paediatric studies.^{17 18} The most recent of which evaluated the use of AVPU in the prehospital setting to identify children who might require intubation or intensive care and concluded that an AVPU of A or V identified 100% of children with a pGCS of or exceeding eight, and therefore, at low risk of requiring intubation or intensive care treatment.¹⁸

GCS is a composite scoring system of three components which share no relationship and there are many clinically plausible score combinations.¹⁹ It is important to remember that the total GCS cannot be seen as a static and exact scale like the simpler scores and it should be used to measure change in each of its components with the total score to track the progress and consciousness of a patient. This emphasises the need for correct practice using the score, stating the component scores alongside total GCS on every communication and documentation as recommended by NICE. In this study only 75.4% of GCS scores had the component scores listed. This, however, does not take away the validity of using the total score as a guideline for the clinicalmanagement, that is, when a CT scan is recommended or appropriate airway intervention and the involvement of an anaesthetist.³

Prehospital GCS is a reasonable indicator of GCS in EDs and may be helpful in determining which children are at risk of serious head injury and require direct transfer to major trauma facilities, either in isolation or as part of a composite tool to be used in such situations.

However, for one in four children the GCS will change by the time they reach ED and ongoing monitoring with GCS in the prehospital period including all component scores is essential.

This study is the largest one to explore the equivalence of AVPU to GCS in children admitted to hospital with head injury, and the only one that attempts to compare the outcome for the two scoring systems in terms of investigations and diagnostic yield of serious cranial and ICI. The findings are limited by its retrospective and multicentre design that may have impaired data completeness and variation in data quality between centres. Data were extracted from hospital case notes and while there may have been administrative errors that explained outlying results, clinical governance should ensure a level of accuracy within the case notes. We were unable to follow-up children who did not have CT and identify potentially missed cases of ICI or depressed fracture. While it was stated that measures were taken at the same point in the care pathway, we cannot be sure that temporal differences did not have an effect. Study numbers in this field will always be limited by the lower numbers of children with severe loss of consciousness, however this represents the real-world epidemiology of head injury where the majority of cases seen are minor head injuries.

Conclusion

Despite the current NICE guidelines, 25% children with head injury did not have a GCS recorded in the ED rising to 40% of prehospital cases. This study found that the equivalence of AVPU to GCS varied between children <5 years and >5 years. The use of AVPU alone at the initial hospital assessment in infancy did not adversely affect the rate of initial neuroradiological investigation or diagnostic yield. When used in isolation in older children it predicted a lower rate of CT imaging and lower diagnostic yield. We would recommend that use of the simple AVPU is beneficial to initial assessment of infants with head injury but is not sensitive enough to monitor change in levels of consciousness and would, therefore, not be recommended for ongoing monitoring of clinical status in this age group.

Supplementary Material

Acknowledgments

Members of the original and subsequent CMACE Head Injury External advisory group: Professor Robert Tasker, Paediatrics, University of Cambridge; Dr Rosemary Arthur, Consultant Paediatric Radiologist, Leeds (British Society Paediatric Radiology); Mr Richard Edwards MD, Department of Neurosurgery, Bristol Hospital for Children; Ms Rosie Houston Research fellow CMACE; Dr Phillip Hyde MBBS, Paediatric Intensive Care Unit, Southampton Children’s Hospital; Dr Ian Maconochie PhD, Imperial College NHS Healthcare Trust, London, UK, Dr Fiona Lecky, Research Director TARN, Senior Lecturer, Honorary Consultant Emergency Medicine, Manchester; Dr Fiona Moore, Medical Director London Ambulance Service; Dr Kevin Morris, Director PICU Birmingham Children’s Hospital; Dr Roger Parslow PhD, Senior Lecturer in Epidemiology, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds; Dr Gale Pearson Consultant in Intensive Care, Birmingham Children’s Hospital; Lisa Turan, Chief Executive Child Brain Injury Trust; Girkamal Virdi, Assistant Head of Clinical and Audit Research, London Ambulance Service; Mark Woolco*ck, Emergency Medical Practitioner and Emergency Specialist Service, South Western Ambulance Service, NHS Foundation Trust.

Footnotes

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