Therapy A trial of intracranial-pressure monitoring in traumatic brain injury.
This review may be edited
Summary
Posted By:	Elizabeth Sweetman and Gordon Doig
E-Mail:	esweetman@med.usyd.edu.au
Posted Date:	22.04.2013
Title:	A trial of intracranial-pressure monitoring in traumatic brain injury.
Authors:	Chesnut RM, Temkin N, Carney N, Dikmen S, Rondina C, Videtta W, Petroni G, Lujan S, Pridgeon J, Barber J, Machamer J, Chaddock K, Celix JM, Cherner M, Hendrix T.
Reference:	N Engl J Med. 2012 Dec 27;367(26):2471-81.
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Abstract:	BACKGROUND: Intracranial-pressure monitoring is considered the standard of care for severe traumatic brain injury and is used frequently, but the efficacy of treatment based on monitoring in improving the outcome has not been rigorously assessed. METHODS: We conducted a multicenter, controlled trial in which 324 patients 13 years of age or older who had severe traumatic brain injury and were being treated in intensive care units (ICUs) in Bolivia or Ecuador were randomly assigned to one of two specific protocols: guidelines-based management in which a protocol for monitoring intraparenchymal intracranial pressure was used (pressure-monitoring group) or a protocol in which treatment was based on imaging and clinical examination (imaging-clinical examination group). The primary outcome was a composite of survival time, impaired consciousness, and functional status at 3 months and 6 months and neuropsychological status at 6 months; neuropsychological status was assessed by an examiner who was unaware of protocol assignment. This composite measure was based on performance across 21 measures of functional and cognitive status and calculated as a percentile (with 0 indicating the worst performance, and 100 the best performance). RESULTS: There was no significant between-group difference in the primary outcome, a composite measure based on percentile performance across 21 measures of functional and cognitive status (score, 56 in the pressure-monitoring group vs. 53 in the imaging-clinical examination group; P=0.49). Six-month mortality was 39% in the pressure-monitoring group and 41% in the imaging-clinical examination group (P=0.60). The median length of stay in the ICU was similar in the two groups (12 days in the pressure-monitoring group and 9 days in the imaging-clinical examination group; P=0.25), although the number of days of brain-specific treatments (e.g., administration of hyperosmolar fluids and the use of hyperventilation) in the ICU was higher in the imaging-clinical examination group than in the pressure-monitoring group (4.8 vs. 3.4, P=0.002). The distribution of serious adverse events was similar in the two groups. CONCLUSIONS: For patients with severe traumatic brain injury, care focused on maintaining monitored intracranial pressure at 20 mm Hg or less was not shown to be superior to care based on imaging and clinical examination. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01068522.).
Are the Results Valid?
1. Was the assignment of patients to treatments randomized? ( Was allocation concealment maintained?)
	Yes. Eligible patients were randomly assigned to either the Pressure Monitoring Group or Imaging Clinical Examination Group. Patients were randomised to study group either via a password protected access database or if no computer was available, the study coordinator contacted the Latin American Coordinating Centre. Study personnel at the coordinating centre flipped a coin and informed the study coordinator at the site the treatment assignment (Page 43, Supplementary Appendix) [Comment by Gord - The primary manuscript does not provide an adequate description of allocation concealment. 'Coin flipping' does not provide a verifiable audit trail, nor does it allow for blocking. It is to be discouraged as an allocation process.]
2. Were all patients who entered the trial properly accounted for and attributed at its conclusion?
2a. Was followup complete?
	All patients were accounted for in the trial participant flow chart, Supplemental Appendix Figure S1, page 48. There was an 8% loss to follow up in each trial arm, which is acceptable and outstanding for a TBI study with follow-up at 6 months! 13/157 Patients in the Pressure Monitoring group were loss to follow up by 6 months and 14/167 Patients in the Imaging Clinical Examination Group were loss to follow up by 6 months (Suppl Appendix, Figure S1, page 48).
2b. Were patients analyzed in the groups to which they were randomized?
	Yes patients were analysed in the groups to which they were randomised.
3. Were patients, health workers, and study personnel blind to treatment?
	Outcome assessors were blinded to group assignment at 3 and 6 month follow-up.
4. Were the groups similar at the start of the trial?
	The study groups were similiar at baseline (Table 6S, Suppl Appendix, p.59)
5. Aside from the experimental intervention, were the groups treated equally?
	(Table 3, Table 9S p.76) Statistically greater use of hypertonic saline, mannitol and hyperventilation in the imaging clinical examination group vs pressure monitoring group. Statistically greater use of barbituates in pressure monitoring group vs imaging clinical examination group.
What are the Results?
1. How large was the treatment effect?
	Primary Outcome - Functional and cognitive status at 6 months (based on percentile performance across a composite of 21 components, see page 2473, outcomes section for more details): Pressure Monitoring Group Score 56 vs Imaging Clinical Examination Group Score 53 ; Odds Ratio 1.09, P = 0.49 Mortality at 6 months: Pressure Monitoring Group 39% vs Imaging Clinical Examination Group 41% ; Odds Ratio 1.10, P = 0.60
2. How precise was the estimate of the treatment effect?
	Primary Outcome: Functional and cognitive status at 6 months Pressure Monitoring Group vs Imaging Clinical Examination Group (95% CI 0.74 - 1.58) Mortality at 6 months: Pressure Monitoring Group vs Imaging Clinical Examination Group (95% CI 0.77 - 1.57)
Will the Results Help Me In Caring For My Patients?
1. Can the results be applied to my patient care?
	As ICP monitoring in Intensive Care is standard practice in head injured patients in developed nations, the results of this trial may not be generalisable to these ICU patient populations.
2. Were all clinically important outcomes considered?
	Yes.
3. Are the likely treatment benefits worth the potential harms and costs?
	The 95% confidence interval around the primary outcome is not narrow enough to declare that no treatment difference exists between groups. Although this trial was 'negative', it cannot be used to declare that treatment outcomes are 'similar'.
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