1. Do children WITH BLUNT head trauma and normal CT scan require hospitalization for neurological observation?

2. 2. study design? Prospective, multicenter observational analytic cohort planned sub-study.Prospective, multicenter observational analytic cohort planned sub-study. RedesignRedesign -primary prospective randomised study- patients randomised to either hospital stay or discharge home.-primary prospective randomised study- patients randomised to either hospital stay or discharge home. -All patients receive receive a either a repeat CT or MRI, not both at end of 1 week, or if their GCS drops.-All patients receive receive a either a repeat CT or MRI, not both at end of 1 week, or if their GCS drops. Do a power calculation before setting up the studyDo a power calculation before setting up the study

3. 2. What is sensitivity analysis? Sensitivity analysis is a way to predict the outcome of a decision if the situation turns out to be different. Assumptions are made when key values are missing and values are put in. The results are then compared with initial analysis, which excludes the missing data.Sensitivity analysis is a way to predict the outcome of a decision if the situation turns out to be different. Assumptions are made when key values are missing and values are put in. The results are then compared with initial analysis, which excludes the missing data. Normally used to deal with missing data or drop outsNormally used to deal with missing data or drop outs Worst case scenario was used in this paper.Worst case scenario was used in this paper. Sensitivity analysis for subsequent traumatic findings was 0.5% for pts with GCS 15 and 1% for pts with GCS 14.Sensitivity analysis for subsequent traumatic findings was 0.5% for pts with GCS 15 and 1% for pts with GCS 14.

4. 3.What is negative predictive value? The proportion of subjects with a negative test result who do not have the illnessThe proportion of subjects with a negative test result who do not have the illness D/C+DD/C+D We can safely predict that your child will not require any neurosurgical intervention with 95% confidence. However there is 1% chance of having a traumatic finding on subsequent scans.We can safely predict that your child will not require any neurosurgical intervention with 95% confidence. However there is 1% chance of having a traumatic finding on subsequent scans. NPV will change with prevalence of the disorder. If prevalence increases NPV will decrease. However it may not change simply by doubling the population.NPV will change with prevalence of the disorder. If prevalence increases NPV will decrease. However it may not change simply by doubling the population.

5. 4. List two limitations of this study-Authors limitations Not all patients enrolled to the primary study underwent CT head- Selection BiasNot all patients enrolled to the primary study underwent CT head- Selection Bias Most patients with negative CT did not undergo a repeat CT head.Most patients with negative CT did not undergo a repeat CT head. Lack of standardization in the level of CT reporting.Lack of standardization in the level of CT reporting. Long term assessment of neuro-cognitive function was not done.Long term assessment of neuro-cognitive function was not done. Some patients had social admissions.Some patients had social admissions.

6. other limitations Secondary studySecondary study Large number of patients were excluded from the study- 30361Large number of patients were excluded from the study- 30361 Performance bias- patients hospitalized v.s persons dischargedPerformance bias- patients hospitalized v.s persons discharged Although large number of patients enrolled actual power calculation was not performed.Although large number of patients enrolled actual power calculation was not performed.

7. strengths of this study Large sample size- patient no (135443)Large sample size- patient no (135443) MulticenterMulticenter Prospective study and easily generalizable.Prospective study and easily generalizable. Good follow up method and rate 79%Good follow up method and rate 79% Suggested Practice change- for blunt head injury with GCS>14. Observe at home if initial CT is normal may be followed by in clinic in 1 week time for a repeat CT.Suggested Practice change- for blunt head injury with GCS>14. Observe at home if initial CT is normal may be followed by in clinic in 1 week time for a repeat CT.

8. 1. Summarize the paper in 200words? IMRADIMRAD Introduction- The aim of this study was to identify the frequency with which children with minor blunt head injury and normal initial CT scan results have either traumatic findings identified on a subsequent neuroimaging study or the need for neurosurgery in their follow up.Introduction- The aim of this study was to identify the frequency with which children with minor blunt head injury and normal initial CT scan results have either traumatic findings identified on a subsequent neuroimaging study or the need for neurosurgery in their follow up. Methods-Design-prospective observational study-Setting- 25 ED across the US.Methods-Design-prospective observational study-Setting- 25 ED across the US. Population-<18 with blunt head trauma. GCS=14 or 15. Normal CT head.Population-<18 with blunt head trauma. GCS=14 or 15. Normal CT head.

9. Index test-initial CTIndex test-initial CT Reference test- follow up CTReference test- follow up CT Outcome measure- traumatic findings on subsequent CT or MRI and neurosurgical intervention.Outcome measure- traumatic findings on subsequent CT or MRI and neurosurgical intervention. Follow up- hospitalized patients-neurological outcome. Discharged patients-telephone/mail follow up.Follow up- hospitalized patients-neurological outcome. Discharged patients-telephone/mail follow up. RESULTSRESULTS 13453 pts ----93%(12584) GCS 15- & 7% (957) GCS 1413453 pts ----93%(12584) GCS 15- & 7% (957) GCS 14 18% (2485)Hospitalized- 17% of GCS 15 & 39% of GCS 1418% (2485)Hospitalized- 17% of GCS 15 & 39% of GCS 14

10. 2%(197) received subsequent CT or MRI scan2%(197) received subsequent CT or MRI scan 21 patients had traumatic finding on their subsequent CT/MRI scans- 15 with GCS 15 and 6 with GCS14.21 patients had traumatic finding on their subsequent CT/MRI scans- 15 with GCS 15 and 6 with GCS14. NPV for neurosurgical intervention in either groups were 100% CI 95%.NPV for neurosurgical intervention in either groups were 100% CI 95%. DISCUSSION- Children with blunt injury head with initial GCS 14 or 15 and a normal CT are at a low risk for subsequent traumatic findings on neuroimaging and unlikely to require neurosurgical intervention.DISCUSSION- Children with blunt injury head with initial GCS 14 or 15 and a normal CT are at a low risk for subsequent traumatic findings on neuroimaging and unlikely to require neurosurgical intervention.