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Clinical and test features predict non-survivors of
anoxic-ischaemic coma
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Clinical
signs on day 3 (absence of pupil reflex or motor response to pain) predict
patients will die or remain in persistent vegetative state.
Absence of somatosensory evoked potentials in first week after event
predicts similarly bad outcome.
Level 2a evidence (systematic review of cohort studies) |
Citation/s:
Systematic review of
early prediction of poor outcome in anoxic-ischaemic coma. Lancet 1998; 352:
1808 - 12.
Lead author's name and fax: EGJ Zandbergen, Department of Neurology,
University of Amsterdam.
Three-part
Clinical Question: In patients with anoxic / ischaemic coma, what clinical
signs are useful in predicting survival or death?
Search Terms:
1. coma/ (1233), 2. hypoxia, brain/ or anoxia/ (6681), 3. brain ischaemia/
(7154), 4. 2 or 3 (13321), 5. 1 and 4 (69), 6. diagnosis filter (895861), 7. 5
and 6 (58).
Data Sources: : Medline, Embase, non-English sources, Reference lists of
articles found.
Study Selection: SR of cohorts. This is not a SR on a treatment effect.
It is a study of the usefulness of a diagnostic sign/s: so follow a group or
groups of patients over time and see what happens. Randomisation NOT
appropriate.
Data Extraction: Patients with anoxic-ischaemic coma, or if mixed
population separate data for patients with anoxic-ischaemic coma. Excluded
patients with coma from other medical causes or trauma. study criteria: > 10
years old, consecutive unselected patients, unequivocal description, clinical or
neurophysiological data related to outcome. Used GCS, pupil reflex, corneal
reflex, eye movements, epilepsy, SSEP from median N stimulation, EEG. Outcome
classified: poor (death or PVS), or good (any other outcome).
The studies were multiple independent
reviews of individual reports. They were tested for heterogeneity.
The Evidence:
Diagnostic tests best summarised as
likelihood ratios: LRs > 10 greatly increase chance of outcome (in this case
death or PVS)
GCS M = 1 on day 3
LR 16.8 (95% CI 3.4 – 84.1)
Absent pupillary reaction to light on
day 3 LR 10.5 (95% CI 2.1 –
52.4)
Bilateral absence of SSEP in first
week LR 12.0 (95% CI 5.5 –
27.8)
Comments:
1. Predominantly cardiac arrest patients.
2. Clinical signs of no use in predicting non-survivors in first 2 days after
event.
3. Important outcomes: death or persistent vegetative state.
4. Bed side testing on day 3 after event can reliably predict who will die or
remain in PVS.
5. SSEP least susceptible to effects of drugs.
6. A SpPIn situation: tests of high Specificity if Positive
rule the diagnosis In. Specificity of above tests is 100%
7. No one with above signs /test results had a good outcome (any outcome
other than death or PVS).
8. But note follow-up limited to 1 month – too early to diagnose PVS.
Appraised by: Malcolm
Daniel, Department of Anaesthesia, Glasgow Royal Infirmary; Monday, December 10,
2001
Email: md23s@udcf.gla.ac.uk
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