D is for Disability (part 2 of 2)

20 October, 2010 by: colinparker

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Severe Head Injury: is any treatment proven to work? Join us as we explore the literature behind currently accepted treatments for serious traumatic brain injury, in particular the role for therapeutic hypothermia.

Of all the things we do in the ED for severely head-injured children in the acute phase, the most important are probably to maintain oxygenation and perfusion of the brain.  The evidence base supporting other interventions is less clear, but these may still make sense from a pathophysiologic perspective.  Therapeutic hypothermia, in various forms, has been studied by a number of groups.  Sit back and relax, while we talk you through it…


D is for Disability: Advanced Topic: Therapeutic Hypothermia for TBI

First, we review some reviews on the current state of play for treatment of Traumatic Brain Injury (TBI).

Reviews

Moppett 2007

Traumatic brain injury: assessment, resuscitation and early management. IK Moppett.
British Journal of Anaesthesia 2007; 99: 18-31
30% patients admitted to hospital with GCS <13 ultimately die
For severe TBI, only 20% make good recovery (on GOS)
1/3rd who die will talk or obey commands before death, suggesting that initial injury per se is not lethal; secondary insults include ischaemia, re-perfusion, hypoxia
GCS discussed (Table of modifications with variable top score at different ages, P-GCS ?less sensitive to changes than adult score, reasonable intra- & inter-observer reliability, AVPU not been subjected to validation, categories correspond to Swedish Reaction Scale)
Hypotension: duration and number of episodes correlate with mortality
Hypoxia: less strong association, maybe less important for children
CO2: hypercapnea more common with multiple trauma, aggressive hyperventilation worsens outcome (<30mmHg = 4kPa)

Guidelines for BP, oxygenation and CO2 differ (USA=BTF, Europe=EBIC, UK=AAGBI)
Cochrane review – no evidence to support use of mannitol
Early (pre-hospital) intubation – conflicting results, possibly harmful
Tight glycaemic control risky and No benefit (mortality & 6-month outcome)
Spinal injury more likely as severity of head injury increases – CT neck when scanning head
Seizures increase metabolic rate and raise ICP, Phenytoin (& CMZ) decrease risk of early seizures (but not mortality or long-term seizures)

Pharmacologic treatments disappointing (Calcium channel blockers, Mg, amino-steroids/lazaroids, dexanabinol, high-dose steroids – increased mortality via unclear mechanism – not infection or GI bleeding)

Orliaguet 2008

Management of critically ill children with traumatic brain injury. Orliaguet GA, Meyer PG, Baugnon T.
Pediatric Anesthesia 2008; 18: 455-461

Walker 2009

Modern approaches to pediatric brain injury therapy.  Walker PA, et al.
Journal of Trauma 2009; 67: S120-S127

TBI-Hypothermia Papers

Let’s go back in time, to when it all started… Then we’ll skip forward to the last decade or so.

Hendrick 1959

The use of hypothermia in severe head injuries in childhood. E Bruce Hendrick.
Archives of Surgery 1959; 79: 362-364
Beneficial effects of reducing body temperature on the brain, decreased cerebral oedema and increased ability to resist hypoxia

Ice-packs to trunk, cooled to 31-32 (improved vital signs noted), if improving or static after 72hrs, gradually rewarmed to 35.
Re-cooled if deterioration on rewarming, average 13 days (3-35 days)
18 decerebrate cases with severe TBI
10 survivors, 4 normal, no vegetative or institutional care patients.

Marion 1997

The treatment of traumatic brain injury with moderate hypothermia.  Marion DW, et al.
The New England Journal of Medicine 1997; 336: 540-546
RCT 82 patients GCS 3-7 (=severe closed head injury)
Cooled to 33, 10 hrs after injury, for 24hrs only
Improved outcomes at 3 months and 6 months (risk 0.2 for bad outcome), only for subgroup with GCS 5-7, not at 12 months
Probably not cooled soon, cold or long enough.

Shann 2003

Hypothermia for traumatic brain injury: how soon, how cold, and how long? Shann F
The Lancet 2003; 362: 1950-1951

Hutchison 2008

Hypothermia therapy after traumatic brain injury in children.  Hutchison JS, et al.
The New England Journal of Medicine 2008; 358: 2447-2456

Taylor 2001

A randomized trial of very early decompressive craniectomy in children with traumatic brain injury and sustained intracranial hypertension.  Taylor A, et al.
Child’s Nervous System 2001; 17: 154-162
Authors include Frank Shann & Jim Tibballs
RCT of early (19hrs median, 7-29hrs) decompressive craniectomy
Graph very illustrative of better ICP profiles
2/14 controls had good outcome (normal or mild disability) at 6 months
7/13 in decompression group
p=0.046, NS because of multiple peeks near end of study (required p of <0.02)
Therefore labelled a pilot study…

Summary

That’s all Folks!
Expect to hear from us again in 2 weeks, and as always, feel free to share your thoughts via the comments box below…

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