Abstract
OBJECTIVE: Acute pupillary dilation in a head-injured patient is a neurological emergency. Pupil dilation is thought to be the result of uncal herniation causing mechanical compression of the IIIrd cranial nerve and subsequent brain stem compromise. However, not all patients with herniation have fixed and dilated pupils, and not all patients with nonreactive, enlarged pupils have uncal herniation. Therefore, we have tested an alternative hypothesis that a decrease in brain stem blood flow (BBF) is a more frequent cause of mydriasis and brain stem symptomatology after severe head injury. We determined the relation of BBF to outcome and pupillary response in patients with severe head injuries. METHODS: One hundred sixty- two patients with a Glasgow Coma Scale score of 8 or less underwent stable xenon computed tomographic blood flow determination at the level of the superior colliculus, and this blood flow was correlated with pupillary features, intracranial pressure, computed tomographic scan pathology, and outcome. RESULTS: A BBF of less than 40 ml/100 g/min was significantly associated with poor outcome (P < 0.009). In patients with bilaterally nonreactive pupils, the BBF was 30.5 ± 16.8 ml/100 g/min, and in those with normally reactive pupils, the BBF was 43.8 ± 18.7 ml/100 g/min (P < 0.001). Intracranial pressure and the presence of a brain stem lesion observed on the computed tomographic scan did not correlate with BBF, pupillary size, or reactivity. Unfavorable outcome at 12 months was directly related to age (P = 0.062) and inversely related to pupillary responsiveness (P = 0.0006), pupil size (P = 0.005), and BBF of less than 40 ml/100 g/min (P = 0.009). CONCLUSION: These findings suggest that pupillary dilation is associated with decreased BBF and that ischemia, rather than mechanical compression of the IIIrd cranial nerve, is an important causal factor. More important, pupil dilation may be an indicator of ischemia of the brain stem. If cerebral blood flow and cerebral perfusion pressure can be rapidly restored in the patient with severe head injury who has dilated pupils, the prognosis may be good.
| Original language | English |
|---|---|
| Pages (from-to) | 941-948 |
| Number of pages | 8 |
| Journal | Neurosurgery |
| Volume | 44 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 1 1999 |
| Externally published | Yes |
Fingerprint
Keywords
- Brain stem blood flow
- Dilation
- Ischemia
- Outcome
- Pupil
ASJC Scopus subject areas
- Clinical Neurology
- Surgery
Cite this
Brain stem blood flow, pupillary response, and outcome in patients with severe head injuries. / Ritter, Ann M.; Muizelaar, J. Paul; Barnes, Tom; Choi, Sung; Fatouros, Panos; Ward, John; Bullock, Ross.
In: Neurosurgery, Vol. 44, No. 5, 01.05.1999, p. 941-948.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Brain stem blood flow, pupillary response, and outcome in patients with severe head injuries
AU - Ritter, Ann M.
AU - Muizelaar, J. Paul
AU - Barnes, Tom
AU - Choi, Sung
AU - Fatouros, Panos
AU - Ward, John
AU - Bullock, Ross
PY - 1999/5/1
Y1 - 1999/5/1
N2 - OBJECTIVE: Acute pupillary dilation in a head-injured patient is a neurological emergency. Pupil dilation is thought to be the result of uncal herniation causing mechanical compression of the IIIrd cranial nerve and subsequent brain stem compromise. However, not all patients with herniation have fixed and dilated pupils, and not all patients with nonreactive, enlarged pupils have uncal herniation. Therefore, we have tested an alternative hypothesis that a decrease in brain stem blood flow (BBF) is a more frequent cause of mydriasis and brain stem symptomatology after severe head injury. We determined the relation of BBF to outcome and pupillary response in patients with severe head injuries. METHODS: One hundred sixty- two patients with a Glasgow Coma Scale score of 8 or less underwent stable xenon computed tomographic blood flow determination at the level of the superior colliculus, and this blood flow was correlated with pupillary features, intracranial pressure, computed tomographic scan pathology, and outcome. RESULTS: A BBF of less than 40 ml/100 g/min was significantly associated with poor outcome (P < 0.009). In patients with bilaterally nonreactive pupils, the BBF was 30.5 ± 16.8 ml/100 g/min, and in those with normally reactive pupils, the BBF was 43.8 ± 18.7 ml/100 g/min (P < 0.001). Intracranial pressure and the presence of a brain stem lesion observed on the computed tomographic scan did not correlate with BBF, pupillary size, or reactivity. Unfavorable outcome at 12 months was directly related to age (P = 0.062) and inversely related to pupillary responsiveness (P = 0.0006), pupil size (P = 0.005), and BBF of less than 40 ml/100 g/min (P = 0.009). CONCLUSION: These findings suggest that pupillary dilation is associated with decreased BBF and that ischemia, rather than mechanical compression of the IIIrd cranial nerve, is an important causal factor. More important, pupil dilation may be an indicator of ischemia of the brain stem. If cerebral blood flow and cerebral perfusion pressure can be rapidly restored in the patient with severe head injury who has dilated pupils, the prognosis may be good.
AB - OBJECTIVE: Acute pupillary dilation in a head-injured patient is a neurological emergency. Pupil dilation is thought to be the result of uncal herniation causing mechanical compression of the IIIrd cranial nerve and subsequent brain stem compromise. However, not all patients with herniation have fixed and dilated pupils, and not all patients with nonreactive, enlarged pupils have uncal herniation. Therefore, we have tested an alternative hypothesis that a decrease in brain stem blood flow (BBF) is a more frequent cause of mydriasis and brain stem symptomatology after severe head injury. We determined the relation of BBF to outcome and pupillary response in patients with severe head injuries. METHODS: One hundred sixty- two patients with a Glasgow Coma Scale score of 8 or less underwent stable xenon computed tomographic blood flow determination at the level of the superior colliculus, and this blood flow was correlated with pupillary features, intracranial pressure, computed tomographic scan pathology, and outcome. RESULTS: A BBF of less than 40 ml/100 g/min was significantly associated with poor outcome (P < 0.009). In patients with bilaterally nonreactive pupils, the BBF was 30.5 ± 16.8 ml/100 g/min, and in those with normally reactive pupils, the BBF was 43.8 ± 18.7 ml/100 g/min (P < 0.001). Intracranial pressure and the presence of a brain stem lesion observed on the computed tomographic scan did not correlate with BBF, pupillary size, or reactivity. Unfavorable outcome at 12 months was directly related to age (P = 0.062) and inversely related to pupillary responsiveness (P = 0.0006), pupil size (P = 0.005), and BBF of less than 40 ml/100 g/min (P = 0.009). CONCLUSION: These findings suggest that pupillary dilation is associated with decreased BBF and that ischemia, rather than mechanical compression of the IIIrd cranial nerve, is an important causal factor. More important, pupil dilation may be an indicator of ischemia of the brain stem. If cerebral blood flow and cerebral perfusion pressure can be rapidly restored in the patient with severe head injury who has dilated pupils, the prognosis may be good.
KW - Brain stem blood flow
KW - Dilation
KW - Ischemia
KW - Outcome
KW - Pupil
UR - http://www.scopus.com/inward/record.url?scp=0032911961&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032911961&partnerID=8YFLogxK
U2 - 10.1097/00006123-199905000-00005
DO - 10.1097/00006123-199905000-00005
M3 - Article
VL - 44
SP - 941
EP - 948
JO - Neurosurgery
JF - Neurosurgery
SN - 0148-396X
IS - 5
ER -