1. What’s in the Box? A Retrospective Look at CT Head in ICU
WICS Summer Meeting
21st June 2013
Ben Jones
ACCS CT2 Acute Medicine

2. Plan
Aim of the “Project”
Background review
Method
Results
Conclusion

3. “I wonder how many of our CT heads actually change our management?”
How it all began…
Throw away comment on a morning round…
“I wonder how many of our CT heads actually change our management?”

4. Aim of the Project
To explore the indications for, and CT Head findings in, patients in our ICU, and to assess how these impact on further management

5. What has already been done?
A poorly studied area
3 main studies
Balachandaran et al 2009
Salerno et al 2009
Rafanan et al 2000

6. Balachandaran in a nutshell
Aim: to determine the diagnostic benefit of head CT in ventilated patients who remain unresponsive off sedation
Method: Retrospective review of adult patients admitted to a Tertiary MICU in Chicago over a 1-year period
Results: 42/308 (14%) had head CT after > 48 hrs off sedation. 41/42 were non-diagnostic. 90% regained consciousness off sedation, 10% deteriorated clinically or required re-sedation. RASS target -3 to -4 (all patients were -5). Raised Creatinine in 38%, 0% had raised ammonia. 19% had daily sedation breaks.
Conclusion: head CT is of limited diagnostic utility in those who remain unresponsive with no focal neurological findings after discontinuation of sedation, and does not alter management of any patient

7. Salerno in a nutshell
Aim: to assess whether clinical variables would be useful in selecting patients likely to have an abnormality on head CT & to determine the impact of these on management
Method: Retrospective review in Delaware over a 2-year period
Results: 123 pts (16.6%) had a head CT, with a new finding in 26 (21.1%). In those with a new finding on CT, 42% had a change in diagnosis & 23% had a change in treatment
Conclusion: analysis failed to determine any clinical characteristic that could predict a new finding on CT. Suggests that clinicians should have a low threshold for ordering a CT scan in MICU patients with acute neurological dysfunction

8. Rafanan in a nutshell
Aim: to assess whether clinical variables might be useful in selecting patients who will have an acute intra-cranial abnormality on head CT
Method: Retrospective review over a 2-year period in a tertiary care MICU in Cleveland
Results: 230/1228 pts had a head CT (297 scans in total). Of the 297 scans, 37% were positive. Only the presence of neurological deficit differed significantly between +ve & -ve CT scans (70 vs 37%, p<0.001), with Odds Ratio 3.9x greater of having a +ve CT scan with a neurological deficit. Seizures in those with a normal neuro exam were found in 36% of positive CT scans
Conclusion: the presence of either a new neuro deficit or seizures in MICU patients is associated with an acute intra-cranial abnormality, but this association is not powerful enough to reliably depend on these clinically

9. Aim of the Project
To explore the indications and CT Head findings in patients in our ICU, and to assess how these impact on further management

10. Method
Patients who underwent CT Head examination whilst in the Royal Gwent Critical Care Unit between January 1st and September 30th 2012 were identified from the Radiology Archive System.
CT Head examinations performed prior to admission were not included in assessment, but used for comparison

11. Method
Patient demographics and data relating to ICU admission was obtained from ICNARC database
Indication for CT Head and its subsequent report was obtained from Radiology Archive System
Blood results obtained from Clinical Work Station
Neurological assessment pre-CT & management outcome post-CT was obtained from review of case notes
Information relating to daily sedation doses and sedation breaks were taken from Critical Care charts & nursing documentation

12. And Now For Some…..
&

13. Results
49 patients in the period in question underwent CT Head examination
Of these 49, a full set of data was collected for 47
Average age of patient = 53 years
Average APACHE II Score = 15.1

16. Documentation Of Neurology

17. Lumbar Puncture No of CT Scans for ? Infection = 10/ 47
No of lumbar punctures = 7/ 10
No of Positive LP Findings = 1/7

18. Results Average Creatinine on Day of CT = 103
Creatinine Range: 36 to 375
No of patients requiring RRT during admission = 7/47 (14.8%)

19. RIFLE Criteria on Day of CT Head

20. Sedation Sedation used in patient pre-CT Head
46 / 47 (97.8%)
Mechanically ventilated prior to CT Head
Tracheostomy sited under LA

22. Types of Sedation Used

23. Average Sedative Doses
Morphine used in 30 / 47
Average mg / patient
Midazolam used in 33 /47
Average mg / patient
Propofol used in 34 / 47
Average mg / patient
Clonidine used in 2 /47
Average 6850 micrograms / patient

24. 171 treatments for a 40 kg child
Morphine PCA for
64 hours 55 minutes
Clonidine:
171 treatments for a 40 kg child
Midazolam for 69.1 endoscopies
Propofol 174 kcal

25. Management Outcome Post-CT Head

26. Management Outcome Post-CT Head

27. ICU Survival Survival to ICU discharge = 65.9%
Of the 12 patients withdrawn on, 8.3% (1) survived

28. Those Not Waking Up Number = 12 / 47 (25.5%)
No of Neurology documented pre-CT Head
Pupils 3 (1 abn new, 2 normal)
GCS 3 (1 abn wors, 1 abn unch, 1 normal)
Cranial Nerves 0
Power 1 (1 normal)
Tone 1 (1 normal)
Reflexes 1 (1 normal)
Sensation 1 (1 abn new)

29. Those Not Waking Up CT Findings Management Unchanged
Withdrew Management
Normal 5 1
Abnormal New 2
Abnormal Unchanged
Abnormal Worsened

30. Those Not Waking Up RIFLE on Day of CT Head
Nil = 9, Risk = 1, Injury = 1, Failure = 1
Required RRT during ICU admission = 1 / 12
ICU Survival = 7 / 12 (58.3%)

31. Those Not Waking Up Daily Sedation Breaks Sedation Type
Yes = 5, No = 4, N/A = 3
Sedation Type
Morphine & Midazolam & Propofol = 4
Morphine & Midazolam = 4
Midazolam & Propofol = 1
Propofol = 3
Average Sedation Dose
Morphine = 454 mg (8 pts)
Midazolam = mg (9 pts)
Propofol = 1345 mg (8 pts)

32. Those Not Waking Up Average time on ICU before CT
7.5 days (Range 1 to 21)
Average period between CT & stopping sedation
101.1 hours (Range 20 to 350 hours)
2 scans off sedation < 24 hours, both normal

33. Conclusions…

34. Conclusion
Diagnostic dilemma in an investigation with low yield, but potentially high impact on patient outcome (4.2% were transferred to Teriary Care, 70.2% did not change management, 25.6% withdrew care post-CT )
Our data is comparable with that of previous studies
In the subset of patients who were slow to wake off sedation, our data was comparable with Balachandaran et al in terms of findings & poor compliance with sedation breaks

35. Conclusion
Cumulative doses of Morphine & Midazolam were higher in those not waking up compared with others
Neurological assessment pre-CT Head was extremely poor (2-18 / 47)
Focal neurological signs were poorly predictive of normal or abnormal CT findings

36. Conclusion
However, a negative CT scan may be just as important in terms of management
For example to rule out intra-cranial haemorrhage in patients on anti-coagulants or requiring anti-coagulant treatment

37. Impact on Practice
Importance of neurological assessment at first review & daily on ICU
Importance of sedation breaks
Unpredictable nature of clinical picture & CT findings

38. References
Balachandran JS et al. “Head CT is of limited diagnostic utility in critically ill patients who remain unresponsive after discontinuation of sedation.” BMC Anaesthesiology :3.
Salerno D et al. “The role of Head Computer Tomographic scans on the management of MICU patients with neurological dysfunction.”Journal of Intensive Care Medicine (6):
Rafanan AL et al. “Head Computed Tomography in Medical Intensive Care Unit patients: Clinical Indications.” Critical Care Medicine (5):