HEAD INJURY MODULE ASSESSMENT OF HEAD INJURY

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1 HEAD INJURY MODULE Introduction Head injury is common in both adult and paediatric populations. In all-comers with head injury, () 90% present with normal or near-normal consciousness, and mortality is very low (approximately 0.2%) 1. However, head injury accounts for 50% of all trauma-related death. Blunt trauma (consisting of Motor Vehicle Accidents, industrial accidents, falls and assaults) accounts for the majority of traumatic brain injuries in developed countries. Penetrating injuries occur uncommonly but are associated with high levels of morbidity and mortality. An important role of the ED is to identify patients who are at risk of significant complications from their injury or who may ultimately require neurosurgical intervention. Categorisation of Head Injuries Minor: GCS % of all head injury presentations 10-15% of patients will have an abnormal CT scan and 1-3% will require neurosurgical intervention Moderate: GCS 9 13 Severe: GCS 3-8 Primary brain injury refers to the direct injury of parenchyma and vasculature as a result of the traumatic event. Secondary brain injury refers to ongoing or subsequent damage which occurs following the primary event and is wholly preventable. Causes of secondary brain injury include: hypoxia (po 2 <60mmHg (Oxygen saturation < 90%)) hypotension (SBP < 90mmHg) hypoglycaemia hyperpyrexia (T o > 39 o C) prolonged hypocapnia (pco 2 < 30mmHg) ASSESSMENT OF HEAD INJURY The goal of assessment is to identify patients at risk of significant injuries while minimising unnecessary investigation (and radiation exposure in children) and / or observation in those who are low or very low risk of intracranial pathology

2 HISTORY Take a thorough handover from pre-hospital provider considering Mechanism, Injury, Signs and Treatment provided (MIST handover) Enquire as to the presence of any intoxicating substances which may compromise the validity of examination findings High risk features on history include: Dangerous mechanism (Pedestrian struck, Ejection, Fall 3m ) Post injury seizure Significant retrograde amnesia 2 episodes of vomiting Witnessed LOC > 5 min Abnormal drowsiness Anticoagulation / antiplatelet therapy EXAMINATION Examination in the head injured patient should be tailored to identify: Evidence of neurological injury GCS < 13 Focal neurological deficit, posturing Signs of raised ICP pupillary defect Cushing s response papilloedema (not always present acutely) tense fontanelle Evidence of bony injury to skull or base of skull Palpable step/ depressed # Haemotympanum Otorrhoea, Rhinorrhoea Battle s sign, raccoon eyes Any associated injuries which may lead to secondary insult Hypotension Hypoxia Coagulopathy INVESTIGATION Bedside ensure a BSL is taken early to exclude hypoglycaemia Laboratory blood gas sampling is important in severe head injury to identify hypoxia and hyper / hypocarbia Coagulation profile, FBC, Chem20, lipase, BHCG, and Group and Hold are all indicated in severe injury to identify and limit associated injuries

3 Imaging CT imaging Urgent non-contrast CT scanning is the investigation of choice (with sensitivity and specificity approaching 100% for identification of a surgically important lesion) and early neurosurgical consultation vital in patients with significant injury (either clinically or on CT imaging) Strong predictors for abnormal CT imaging: Seizure with no history of epilepsy GCS < 13 Focal neurology Signs BOS # Anticoagulants/Bleeding diathesis Significant amnesia The clinical uncertainty surrounding traumatic head injury, particularly in the less severely injured patient group, and the ready availability of CT scans, have increased the frequency of CT scanning significantly. This has important cost implications, and produces a potential increased risk to patients from radiation exposure, especially the paediatric populations. It is thought the lifetime mortality risk of cancer is 1 in 1500 in a 1 year old and 1 in 5000 in a 10 year old. 13 CT radiation exposure to infant brains has been linked to possible cognitive impairment in adulthood.. Children in particular may also be non-compliant with the scanning process due to fear /agitaton, producing a requirement for sedation, or even intubation (with the associated risk of a general anaesthetic). Several clinical decision rules (CDRs) have been developed to guide the use of CT imaging in head trauma. They were derived with the intention to facilitate more selective ordering of CT scans. A normal CT in the setting of a minor injury and a stable patient usually means that the patient can be safely discharged. If the decision is made not to CT, then a period of observation is often warranted, with no specific evidence to guide the duration of the period of observation. Care does need to be taken in the application of such decision rules. They are not a substitute for clinical judgment. Furthermore, while the decision rules have been developed with the explicit purpose of reducing radiation exposure to patients without increasing the rate of missed injuries, ultimately they do not seem to reduce the amount of CT scans performed. Where a patient has sustained a moderate to severe head injury (GCS < 13), the goal is to have this patient in CT within 15 minutes of arrival to expedite definitive care when required. Appendix A provides examples of such aforementioned decision rules for adult and paediatric patients. Other Investigative Strategies Cranial ultrasound can be employed in the infant with an open fontanelle for the detection of intracranial collections. The sensitivity is less than with CT imaging, but serves as a cheap, safe and easily reproducible imaging option where available. Skull Xray has a limited role in the assessment of head injury.

4 MANAGEMENT OF SUSPECTED/PROVEN TBI The goal of emergency management in traumatic brain injury is to expedite definitive care of the primary injury while preventing secondary brain injury triage to resuscitation area comprehensive non-invasive monitoring position bed on 30 o incline if possible urgent neurosurgical referral for intervention if indicated AIRWAY & BREATHING ensure airway is patent and protected maintain C-spine immobilisation and place soft collar RSI likely indicated if GCS < 9 or loss of airway reflexes Combativeness preventing imaging Respiratory distress or ventilatory insufficiency (either clinically or with evidence of hypoxia on supplemental oxygen (sats < 90% or PaO2 < 60 mmhg) or hypercarbia (PaCO 2 > 40mmHg) Spontaneous hyperventilation (PaCO 2 ~ 30 mmhg) Multi-system injuries requiring intubation for overall stabilisation Ventilator settings FiO 2 initially set at 100% V T of 8mL/kg Rate to achieve pco mmHg PEEP 5cm H 2 O CIRCULATION correct hypovolaemia haemorrhage control where appropriate volume load to maintain MAP mmhg (or appropriate BP for a child s age) to ensure a CPP of approximately 60 mmhg (CPP = ICP MAP) inotropic support may be necessary to achieve target MAP. Noradrenaline is first line. Be mindful in the multi-trauma patient with active haemorrhage as there are often competing interests (such as a need to maintain a higher blood pressure to perfuse the brain, whilst worsening haemorrhage secondary to this increased blood pressure. Consider a SBP mmhg in this situation. place an arterial line early where possible to accurately determine MAP place a central venous line if inotropic support is required DISABILITY Placement of an ICP monitor is indicated if Initial GCS 3-8 and abnormal CT head Initial GCS 3-8 and normal CT head if >40yo, SBP < 90 or any evidence of posturing

5 In general, the ICP treatment threshold is > 20 mmhg SPECIFIC THERAPY Where a patient has an injury amenable to neurosurgical intervention, the goal is to have the patient in theatre within 60 minutes of presentation. This requires early neurosurgical involvement (preferably prior to patient arrival based on pre-hospital notification), with early notification to anaesthetics and theatre teams Neuroprotective strategies should be implemented routinely: o o o o o Nurse head up 30 degrees where possible Loosen ETT ties to prevent venous congestion Ensure neck not flexed Ventilation strategy as per above with avoidance of hyper/hypoventilation Haemodynamic maintenance where appropriate Correction of abnormal coagulation profile where appropriate with goals of: o INR < 1.4 o Platelets 100 o Fibrinogen 1.5 If clinical evidence of raised intracranial pressure or ICP > 20mmHg, strategies to urgently reduce ICP should should be instigated: o 250mL (3mls/kg) of 3% hypertonic saline as boluses to maintain Na o Ventilate to maintain pco (avoid pco 2 < 30) o exclusion of pneumothorax o ensure adequate sedation o neuromuscular blockade o consider cooling (aiming for T o of 34 o C) o consider repeat CT head o urgent neurosurgical notification phenytoin load 15mg/kg over 1 hour if structural abnormality on CT or if history of fitting Prophylactic phenytoin is shown to reduce the frequency of early post traumatic seizures (within 7 days) but does not decrease late post-traumatic seizures 2 At this point in time there does not appear to be a benefit of leveteracitam over phenytoin 3 ADT prophylaxis and cephazolin 1g for penetrating wounds Mannitol osmotherapy can be considered (0.25g/kg 1g/kg) as an alternative to hypertonic saline (or occasionally in conjunction with hypertonic saline at the request of neurosurgery). Care needs to taken when using mannitol to avoid systemic hypotension from the resulting diuresis. Prophylactic hypothermia in patients with severe TBI has not been shown to be beneficial 4 Patients with a minor head injury may be observed in the ED if a decision not to perform at CT was undertaken. A CT should be arranged if any of the following occur: o Drop in GCS below 13 at any time o GCS not improving to 15 at 2 hours o Progressive headache o Ongoing nausea or vomiting (3 or more in children) (?need a reference here)

6 SUPPORTIVE THERAPY if ICP monitor placed aim for cerebral perfusion pressure of 60-70mmHg (CPP = MAP ICP) ongoing sedation and analgesia with morphine & midazolam (or propofol and fentanyl if expected length of intubation < 24h ) place IDC place NGT and allow free drainage maintain Na + > 140 mmol/l maintain normoglycaemia maintenance fluids of normal saline 0.9% 100mL/hr update family where possible and document contact details in chart DISPOSITION Admission: all intubated patients are managed in the ICU unintubated patients with a moderate head injury and GCS 13 are managed in the neurosurgical HDU patients with new, clinically significant injuries on CT require admission for observation. patients with a negative CT scan who are not alert, or have persistent signs (vomiting, severe headache) may benefit from admission for observation and OT (occupational therapy) and consideration should be given to referring to neurosurgery for ongoing review and surveillance Discharge patients on anticoagulation / antiplatelet therapy with a normal CT brain, GCS 15 and no concerning symptoms (headache, nausea / vomiting) may be discharged after a period of observation. The duration of observation is not clear but should be for a minimum of 6 hours. After this time they can be discharged home if they meet clinical and social criteria as outlined below (discharge should not occur after-hours) patients with a mild head injury with a negative CT and who are GCS 15 can be discharged if they meet the clinical and social criteria as outlined below. patients who were observed rather than CT can be discharged if the clinical social criteria below are met. While universal consensus is lacking as to the duration of observation, generally these patients are observed for at least 4 hours from the time of injury. Clinical criteria Normal mental status and behaviour Normal CT head if performed Clinically improving minor post concussive symptoms Social criteria Responsible adult available to observe patient at home Patient able to return easily if deterioration Written and verbal discharge instructions are understood Occupational therapy follow-up to perform PTA (Post-Traumatic Amnesia) testing should be arranged on all patients presenting following minor head injury. Written Head injury Discharge Advice (Appendix B) should be provided to all patients on discharge

7 PROGNOSIS in TRAUMATIC BRAIN INJURY 5 Initial GCS as a marker for prognosis: Initial GCS Mortality Functional survival 3 65% 7.2% 4 45% 14.4% 5 35% 29.3% 6 24% 50.5% % > 68.9% Single recording of hypotension doubles mortality in TBI Significant increase in poor outcome with age > 60 years Prognosis for patients with bilateral fixed and dilated pupils who under go surgery may not be as bad as thought for patients with extradural haematoma 6 : Extradural haematoma mortality 29.7%, with a favouorable outcome (does this need to be defined further?) in 54.3% Subdural haematoma mortality 66.4% and a favourable outcome in 6.6%

8 Appendix A: Clinical Decision Rules Adult population: In adult patients the Canadian CT Head Rule (CCHR) and the New Orleans Criteria (NOC) are examples of clinical decision rules for CT imaging in minor head injury 7. A prospective cohort study validating these two rules found them both to be 100% sensitive for detecting injuries requiring neurosurgical intervention, but the CCHR was more specific and resulted in lower CT rates compared to the NOC. NEXUS II Investigators (from UCLA) also developed a decision rule using recursive partitioning on 13,728 patients presenting to hospital with a blunt head injury % had a significant intracranial injury. They developed the BEAN BASH mnemonic to guide CT head imaging. It had a 98.3% sensitivity at identifying clinically significant head injuries. Unlike the CCHR and the NOC this trial included paediatric patients Canadian CT head Rule CT recommended if GCS and 1 of following : High Risk for Neurosurgical Intervention GCS < 15 2 hours after injury Suspected open/depressed skull # Signs of BOS # 2 episodes of vomiting 65 years old Medium Risk for Brain Injury Detection by CT Retrograde amnesia 30 minutes Dangerous mechanism: Pedestrian struck Ejection from vehicle Fall 3m or 5 stairs Exclusion criteria : GCS < 13, <16yo, warfarin therapy or bleeding diathesis New Orleans Criteria CT required if GCS 15 and 1 of the following: Headache Vomiting 60 yo Drug and alcohol intoxication Persistent anterograde amnesia Visible trauma above the clavicles seizure

9 NEXUS II CT recommended if BEAN BASH Behaviour abnormal Emesis intractible Age > 65yo Neurological deficit Bleeding disorder Altered mental status Skull fracture Haematoma scalp NICE Guideline 1

10 Paediatric Population: There are several clinical decision rules available to guide imaging for paediatric patients with isolated suspected minor head injury, designed to reduce the radiation exposure to paediatric patients and cost associated with un-necessary scans while minimising missed injury. They have no role to play in the multiinjured patients. The CHALICE (Children s Head Injury Algorithm for the prediction of Important Clinical Events) Rule 9 was developed in the UK to be applied specifically to the paediatric population. It was derived from children presenting with any head injury over a 2 ½ year period. In this group the rule had a sensitivity of 98% for the prediction of clinically significant head injury and if applied would have led to a CT scanning rate of 14% (3210) of children presenting with any head injury. Of the population studied 1.2% (281) had an abnormal CT scan, of which half (137) required neurosurgical intervention. CHALICE rule A CT scan is required on arrival if any of the following criteria are present: HISTORY Witnessed LOC > 5 min History of amnesia > 5 min (retrograde or antegrade) Abnormal drowsiness 3 vomits post injury Suspicion of NAI Seizure after head injury in a patient with no history of epilepsy EXAMINATION GCS < 14, or GCS <15 if under 1 yo Suspicion of penetrating/depressed skull injury or tense fontanelle Signs of BOS # Focal neurology Presence of a bruise, swelling or laceration > 5cm if under 1 yo MECHANISM High speed MVA (pedestrian, cyclist or occupant) Fall > 3m High-speed head injury from a projectile A validation study based at the RCH in Melbourne 10 retrospectively applied the CHALICE rule to 1091 children presenting with any head injury. They found implementing the CHALICE rule would double the number of CT scans in this population compared to a decision to scan made on clinical judgement. This has significant implications in paediatrics from a radiation and cost perspective as well as the risks associated with requiring sedation to facilitate scan. Of the patients that did meet the CHALICE criteria and were not scanned (that is the decision not to scan was made on the grounds of clinical judgment) 1.6% had an abnormal CT scan subsequently, none of which required neurosurgical intervention. PECARN (Pediatric Emergency Care Applied Research Network) CT Head Algorithm for Children < 2 (A) and > 2 years old (B) 11 The PECARN algorithm was derived and validated across 25 emergency departments in North America enrolling patients under 18 years of age, of which were younger than 2 years of age. Clinically important traumatic brain injury (citbi) was defined as death from traumatic brain injury, injury requiring neurosurgical intervention, intubation for > 24 hours due to TBI, hospital admission for more than

11 2 nights in association with TBI on CT. TBI in 376 children (0.9%) and 60 (0.1%) required neurosurgical intervention. In the < 2 y age group, the negative predictive value and sensitivity for clinically significant TBI was 100%. In the > 2 y age group the negative predictive value was 99.95% and sensitivity of 96.8%. If applied to the study population, the above algorithm would have led to a reduction of CT scans by 25% in children < 2 y and 20% for children > 2 y.

12 CATCH: Canadian Assessment of Tomography for Childhood Head Injury 12 CATCH: The high-risk factors were 100% sensitive in identifying neurosurgically relevant injuries (specificity of 70%) and the medium-risk factors were 98% sensitive in identifying neurosurgically relevant injuries (specificity of 50%). For high and medium-risk factors combined sensitivity was 98% and specificity 50%. 12 A comparison of CHALICE, PECARN and CATCH was undertaken by Lyttle et al 13. The rules are quite heterogeneous for the factors they incorporate (GCS was the only high-risk factor common to all), the actions they suggest (CHALICE and CATCH were derived to identify children who require a CT while PECARN was derived to identify children who do not, and the populations in which they were developed. The result is that while each is a useful rule, they are not interchangeable and there is still uncertainty as to which should be used.

13 NICE Algorhythm for CT head in Paediatric Patients 1 :

14 Appendix B: Discharge Information Sheet

15 REFERENCES 1. NICE Head Injury Guidelines. Head Injury: Triage, assessment, investigation and early management of head injury in children, young people and adults u[date Guidelines for the Management of Severe Traumatic Brain Injury, 3 rd edition Inaba K et al. A prospective multicentre comparison of levetiracetam verses phenytoin for early posttraumatic seizure prophylaxis. J Trauma Acute Care Surg 2102; 74(3): Andrews PJD et al. Hypothermia for intracranial hypertension after traumatic brain injury. NEJM; 2015 nejm.org 5. Early Indicators of Prognosis in Severe Traumatic Brain Injury, Scotter J et al. Prognosis of patients with bilateral fixed and dilated pupils secondary to traumatic epidural and subdural haematoma who undergo surgery: a systematic review and meta-analysis. Emerg Med J. 2014;0: Stiell I et al. Comparison of the Canadian CT Head Rule and the New Orleans Criteria in Patients with Minor Head Injury. JAMA 2005; 294: Mower et al. Developing a Decision Instrucment to Guide Computed Tomographic Imaging of Blunt Head Injury Patients. J Trauma. 2005;59: Dunning J et al. Derivation of the children s head injury algorithm for the prediction of important clinical events decision rule for head injury in children. Arch Dis Child 2006; 91: Crowe L, Anderson V and Babl F. Application of the CHALICE clinical prediction rule for intracranial injury in children outside the UK: impact on head CT rate. Arch Dis Child 2010; 95: Kuppermann N et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. The Lancet 2009; 374: Osmond M H et al. CATCH: A clinical decision rule for the use of computed tomography in children with minor head injury. CMAJ 2010: 182(4); Lyttle M D et al. Comparing CATCH, CHALICE and PECARN clinical decision rules for paediatric head injury. Emerg Med J 2012; 29: