Diagnostic performance of S100B as a rule-out test for intracranial pathology in head-injured patients presenting to the emergency department who meet NICE Head Injury Guideline criteria for CT-head scan.

BACKGROUND: Traumatic brain injury is a common ED presentation. CT-head utilisation is escalating, exacerbating resource pressure in the ED. The biomarker S100B could assist clinicians with CT-head decisions by excluding intracranial pathology. Diagnostic performance of S100B was assessed in patients meeting National Institute of Health and Clinical Excellence Head Injury Guideline (NICE HIG) criteria for CT-head within 6 and 24 hours of injury. METHODS: This multicentre prospective observational study included adult patients presenting to the ED with head injuries between May 2020 and June 2021. Informed consent was obtained from patients meeting NICE HIG CT-head criteria. A venous blood sample was collected and serum was tested for S100B using a Cobas Elecsys-S100 module; >0.1 µg/mL was the threshold used to indicate a positive test. Intracranial pathology reported on CT-head scan by the duty radiologist was used as the reference standard to review diagnostic performance. RESULTS: This study included 265 patients of whom 35 (13.2%) had positive CT-head findings. Within 6 hours of injury, sensitivity of S100B was 93.8% (95% CI 69.8% to 99.8%) and specificity was 30.8% (22.6% to 40.0%). Negative predictive value (NPV) was 97.3% (95% CI 84.2% to 99.6%) and area under the curve (AUC) was 0.73 (95% CI 0.61 to 0.85; p=0.003). Within 24 hours of injury, sensitivity was 82.9% (95% CI 66.4% to 93.44%) and specificity was 43.0% (95% CI 36.6% to 49.7%). NPV was 94.29% (95% CI 88.7% to 97.2%) and AUC was 0.65 (95% CI 0.56 to 0.74; p=0.046). Theoretically, use of S100B as a rule-out test would have reduced CT-head scans by 27.1% (95% CI 18.9% to 36.8%) within 6 hours and 37.4% (95% CI 32.0% to 47.2%) within 24 hours. The risk of missing a significant injury with this approach would have been 0.75% (95% CI 0.0% to 2.2%) within 6 hours and 2.3% (95% CI 0.5% to 4.1%) within 24 hours. CONCLUSION: Within 6 hours of injury, S100B performed well as a diagnostic test to exclude significant intracranial pathology in low-risk patients presenting with head injury. In theory, if used in addition to NICE HIGs, CT-head rates could reduce by one-quarter with a potential miss rate of <1%.

Can serum biomarkers be used to rule out significant intracranial pathology in emergency department patients with mild traumatic brain injury? A Systemic Review & Meta-Analysis.

BACKGROUND: Interest has mounted into the use of objective clinical biomarkers for traumatic brain injury (TBI). This systematic review and meta-analysis aimed to synthesise the existing evidence investigating the use of serum & plasma biomarkers to exclude significant intracranial injuries seen on CT head scans in patients that present to ED with TBI. METHODS: The primary outcome was to review the diagnostic accuracy (sensitivity & specificity) of S100B, GFAP and UCH-L1 to exclude significant intracranial pathology on CT head scan in adults presenting with TBI. Secondary outcomes investigated biomarker performance at different time points, in isolated TBI and multi-trauma and with pre-specified cut offs. Systematic searches were conducted on MEDLINE ® (via PubMed), Cochrane electronic databases and EMBASE from 1st January 2000 until June 2020. Bias was assessed using QUADAS 2 tool. A narrative synthesis and meta-analysis were performed. PROSPERO registration number CRD42020212206. RESULTS: After screening, 22 papers were included. The total number of patients with TBI was 9,416. There was significant variation regarding study design, population selection and the clinical threshold/decision rule for CT head request. The diagnostic accuracy of S100B as measured by the range of individual sensitivities and specificities were 63-100% and 5-58%, respectively. Individual sensitivities and specificities for GFAP were 67-100% and 0-89% and for UCH-L1 were 61-100% and 21-63.7% respectively. When measured within 3 hours individual sensitivities & specificities for S100B were 98-100% & 20-58% respectively. The quality of evidence for the primary outcome overall was low. The quality of evidence was low for all secondary outcomes apart from studies that used a pre-specified cut off for S100B which had a moderate strength of evidence. CONCLUSION: The overall quality of evidence regarding the diagnostic accuracy of single biomarkers as a rule out for significant intracranial injury seen on CT head scans in ED patients with TBI is low. Based on current evidence, S100B is the only single biomarker with a validated clinical platform, pre-determined cut off threshold and moderate quality evidence; at this stage making it the biomarker of choice. More robust clinical outcome and economic impact data is required to support its incorporation into clinical decision tools.

Alcohol and acute traumatic brain injury in the emergency department.

OBJECTIVE: There is limited research from Australasian EDs describing the demographic make-up, injury severity and impact of alcohol in patients requiring computed tomography (CT) for suspected traumatic brain injury (TBI). The present study aims to review the frequency and presenting patterns of patients who consume alcohol prior to presenting with suspected TBI. METHODS: Retrospective observational study of patients referred for head CT to exclude TBI from a major referral centre and regional ED in New Zealand, between 1 September 2018 and 31 August 2019. Comparison groups were defined as 'alcohol involved' or 'no alcohol involved'. RESULTS: 97/425 (22.8% [95% CI 18.3-27.4]) of included TBI presentations involved alcohol. 73/97 (75.3% [95% CI 58.6-93.5]) were male and 41/97 (42.3% [95% CI 29.3-55.2]) were aged 18-30 years. The alcohol group were more likely to report assault as the injury mechanism (19.6% [95% CI 10.8-28.4] vs 5.2% [95% CI 2.7-7.7], P < 0.05) and have Glasgow Coma Scale scores reflecting more moderate (13.5% [95% CI 5.9-21.1] vs 3.5% [95% CI 1.5-5.6]) and severe (5.6% [95% CI 0.7-10.5] vs 3.2% [95% CI 1.2-5.2] TBI. Presentation times post-injury were delayed compared to the no alcohol group (3.4 h [interquartile range 1.9-14.8] vs 2.8 h [interquartile range 1.8-6.6], P < 0.05). CONCLUSION: One quarter of patients with suspected TBI had consumed alcohol prior to their injury. Predominantly, those affected were young males who reported higher rates of assault; however, alcohol use was recorded in all age groups and sex. Alcohol-affected patients presented later, potentially delaying time to diagnosis. The present study supports the call for public health interventions that aim to reduce alcohol misuse.

Effect of simulation training on nurse leadership in a shared leadership model for cardiopulmonary resuscitation in the emergency department.

OBJECTIVE: Empowering a senior nurse in a shared leadership role has been proposed as a more efficient set up for the cardiac arrest team in ED. In this model, a senior nurse leads the cardiac arrest algorithm which allows cognitive off-loading of the lead emergency physician. The emergency physician is then more available to perform tasks such as echocardiography and exclude reversible causes. Simulation provides an opportunity for training and practice of this shared leadership model. We hypothesised that a structured simulation training programme that focused on implementing a nurse and doctor shared leadership model for cardiopulmonary resuscitation (CPR), would improve leadership and teamwork quality in the setting of cardiac arrest as measured by a Trauma Non-technical Skills (T-NOTECHS) teamwork scale. METHODS: Fifteen senior ED nurses participated in this pre-interventional post-observational study. Training consisted of a didactic course on team leadership and crisis resource management (CRM) followed by 4 × 10-min resuscitation scenarios with a structured debrief focusing on team leadership skills and CRM. The primary outcome was measured on scenarios 1 and 4 using a modified T-NOTECHS teamwork scale. RESULTS: A statistically significant increase in the T-NOTECHS scale was detected for the measures of leadership (P = 0.0028), CRM (P = 0.0001), adherence to New Zealand Resuscitation Council ALS algorithm (P = 0.0088) and situational awareness (P = 0.0002). CONCLUSION: The present study shows that a short simulation training programme improved nurse leadership and teamwork performance in the setting of a shared leadership model for CPR in the ED which could easily be replicated in other departments.

Addition of Nasal Cannula Can Either Impair or Enhance Preoxygenation With a Bag Valve Mask: A Randomized Crossover Design Study Comparing Oxygen Flow Rates.

BACKGROUND: A critical safety component of emergency anesthesia is the avoidance of hypoxemia during the apneic phase of a rapid sequence intubation. Preoxygenation with a bag valve mask (BVM) or anesthetic circuit may be improved with supplemental oxygen by nasal cannula (NC) if there is a mask leak. In addition, NC is recommended for apneic oxygenation after induction and may be placed before preoxygenation. However, the optimum NC flow rate for preoxygenation or whether the presence of NC alone creates a mask leak remains unclear. METHODS: We performed a randomized crossover study on healthy volunteers comparing BVM alone and BVM with NC flow rates of 0 (NC-0), 5 (NC-5), 10 (NC-10), and 15 (NC-15) liters per minute (lpm). Our primary outcome was end-tidal oxygen (ETO2) after 3-minute preoxygenation. RESULTS: There was no difference in ETO2 between NC-15, NC-10, or BVM-only at 3 minutes. NC-0 and NC-5 recorded significantly lower ETO2 at all times compared with NC-15, NC-10, or BVM-only (least difference NC-5, -7% [95% confidence interval {CI}, -4% to -10%), NC-0, 16% [95% CI, 13%-19%]). There was a difference in ETO2 between NC-15 and BVM-only at 1 minute (7%; 95% CI, 5%-9%), but not at 2 or 3 minutes. There was no difference in ETO2 between NC-10 and NC-15. CONCLUSIONS: Our study found that NC at 0 and 5 lpm with a BVM is deleterious to preoxygenation and should be avoided. In addition, a lack of difference between NC-10 and BVM-only demonstrates that NC at flows of at least 10 lpm should not impair the preoxygenation process. While NC-15 may offer a benefit by reaching maximal ETO2 at 1 minute, this would need to be balanced against patient comfort.

Challenges in the diagnosis of ethylene glycol poisoning.

Ethylene glycol poisoning, while uncommon, is clinically significant due to the associated risk of severe morbidity or lethality and it continues to occur in many countries around the world. The clinical presentation of ethylene glycol toxicity, while classically described in three phases, varies widely and when combined with the range of differential diagnoses that must be considered makes diagnosis challenging. Early and accurate detection is important in these patients, however, as there is a need to start antidotal treatment early to prevent serious harm. In this article, we will review the literature and provide guidance regarding the diagnosis of ethylene glycol poisoning. While gas chromatography is the gold standard, the usefulness of this test is hampered by delays in access due to availability. Consequently, there are several surrogate markers that can give an indication of ethylene glycol exposure but these must be interpreted with caution and within the clinical context. An in-depth review of these tests, particularly the detection of a raised osmolar gap or an raised anion gap acidosis, will form the main focus of this article.

First European case of convulsions related to analytically confirmed use of the synthetic cannabinoid receptor agonist AM-2201.

PURPOSE: There is increasing reported use of synthetic cannabinoid receptor agonists (SCRA) across Europe. To date, there is limited information on the acute toxicity (harm) related to the use of these products. We describe here a case in which an individual developed convulsions related to the use of the SCRA AM-2201. CASE REPORT: A 20 year old male smoked a "Spice" (SCRA-containing) product called "Black Mamba," and rapidly after smoking, he had a generalised self-terminating tonic-clonic convulsion. After a 2 h observation period in the Emergency Department (ED), he self-discharged against medical advice. Subsequent analysis of urine collected at the time of presentation to the ED detected metabolites of AM-2201; no other drugs were detected on extensive analytic screening. DISCUSSION: This is the first case of convulsions related to the use of SCRA described in Europe, and the first case of convulsions related to the use the SCRA AM-2201 confirmed by analysis of biological samples. It is important for emergency physicians, clinical toxicologists and clinical pharmacologists managing those presenting with acute toxicity related to the use of SCRA to analytically confirm the exact compound(s) involved, to enable accurate description of the acute toxicity associated with individual SCRA.

Paracetamol toxicity: What would be the implications of a change in UK treatment guidelines?

BACKGROUND: Treatment of single-time-point ingestion acute paracetamol (acetaminophen) poisoning with N-acetylcysteine (NAC) is guided by plotting a timed plasma paracetamol concentration on established nomograms. Guidelines in the UK differ from those in the U.S. and Australasia by having two treatment lines on the nomogram. Patients deemed to be at 'normal' risk of hepatotoxicity are treated using the treatment line starting at 200 mg/L at 4 h post-ingestion; those at higher risk are treated using the 'high risk' treatment line starting at 100 mg/L at 4 h post-ingestion. AIM: To examine the effect on treatment numbers if UK guidelines were to adopt a single treatment line nomogram or lower, risk-stratified treatment lines. METHODS: We undertook a retrospective analysis of a series of acute single-time-point paracetamol poisonings presenting to our inner city emergency department. Treatment numbers and effect on treatment costs were modelled for three alternative scenarios: a 150 line-a combined single treatment line starting at a 4 h concentration of 150 mg/L, a 100 line-a combined single treatment line starting at a 4 h concentration of 100 mg/L, and a 150/75 line-a double treatment line at the lower concentrations of 150 mg/L for normal risk and 75 mg/L for high risk patients. RESULTS: A total of 1,214 cases were identified. Under current UK guidance, 133 (11.0%) high risk cases and 98 (8.1%) normal risk cases needed treatment (total 231, 19.0%). A 150 line would result in 87 (7.2%) high risk cases and 155 (12.8%) normal risk cases needing treatment (total 242, 19.9%). A 100 line would result in 133 (11.0%) high risk and 251 (20.7%) normal risk cases needing treatment (total 384, 31.6%). A 150/75 line would result in 153 (12.6%) high risk and 155 (12.8%) normal risk cases needing treatment (total 308, 25.4%). CONCLUSIONS: Both a 100 line and a 150/75 line would result in a large increase in the number of patients being treated and an associated increase in the costs of treatment. A single 150 mg/L treatment line would simplify treatment algorithms and lead to a similar number of patients being treated with NAC overall. A potential concern however is whether any of the high risk cases that would no longer be treated might develop significant hepatotoxicity. After consideration of the evidence for dual treatment lines, we feel that these risks are small and that it is worth reconsidering a change of treatment recommendations to a single 150 line.

Management of acute paracetamol (acetaminophen) toxicity: a standardised proforma improves risk assessment and overall risk stratification by emergency medicine doctors.

BACKGROUND: Paracetamol (acetaminophen) poisoning is the most common toxicological presentation in the UK. Doctors managing patients with paracetamol poisoning need to assess the risk of their patient developing hepatotoxicity before determining appropriate treatment. Patients deemed to be at 'high risk' of hepatotoxicity have lower treatment thresholds than those deemed to be at 'normal risk'. Errors in this process can lead to harmful or potentially fatal under or over treatment. AIM: To determine how well treating doctors assess risk factor status and whether a standardised proforma is useful in the risk stratification process. METHODS: Retrospective 12-month case note review of all patients presenting with paracetamol poisoning to our large inner-city emergency department. Data were collected on the documentation of risk factors, the presence of a local hospital proforma and treatment outcomes. RESULTS: 249 presentations were analysed and only 59 (23.7%) had full documentation of all the risk factors required to make a complete risk assessment. 56 of the 59 (94.9%) had the local hospital proforma included in the notes; the remaining 3 (5.1%) had full documentation of risk factors despite the absence of a proforma. A local hospital proforma was more likely to be included in the emergency department notes in those with 'adequate documentation' (78 out of 120 (65%)) than for those with 'inadequate documentation' (16 out of 129 (12.4%)); X(2), p<0.001. CONCLUSIONS: Despite a low overall uptake of the proforma, use of a standardised proforma significantly increased the likelihood of documentation of the risk factors which increase risk for hepatotoxicity following paracetamol poisoning.