Adverse effects of prolonged hyperventilation in patients with severe head injury

A randomized clinical trial

Jan Paul Muizelaar, A. Marmarou, J. D. Ward, H. A. Kontos, S. C. Choi, D. P. Becker, H. Gruemer, H. F. Young

Research output: Contribution to journalArticle

784 Citations (Scopus)

Abstract

There is still controversy over whether or not patients should be hyperventilated after traumatic brain injury, and a randomized trial has never been conducted. The theoretical advantages of hyperventilation are cerebral vasoconstriction for intracranial pressure (ICP) control and reversal of brain and cerebrospinal fluid (CSF) acidosis. Possible disadvantages include cerebral vasoconstriction to such an extent that cerebral ischemia ensues, and only a short-lived effect on CSF pH with a loss of HCO3 - buffer from CSF. The latter disadvantage might be overcome by the addition of the buffer tromethamine (THAM), which has shown some promise in experimental and clinical use. Accordingly, a trial was performed with patients randomly assigned to receive normal ventilation (PaCO2 35 ± 2 mm Hg (mean ± standard deviation): control group), hyperventilation (PaCO2 25 ± 2 mm Hg: HV group), or hyperventilation plus THAM (PaCO2 25 ± 2 mm Hg: HV + THAM group). Stratification into subgroups of patients with motor scores of 1-3 and 4-5 took place. Outcome was assessed according to the Glasgow Outcome Scale at 3, 6, and 12 months. There were 41 patients in the control group, 36 in the HV group, and 36 in the HV + THAM group. The mean Glasgow Coma Scale score for each group was 5.7 ± 1.7, 5.6 ± 1.7, and 5.9 ± 1.7, respectively; this score and other indicators of severity of injury were not significantly different. A 100% follow-up review was obtained. At 3 and 6 months after injury the number of patients with a favorable outcome (good or moderately disabled) was significantly (p < 0.05) lower in the hyperventilated patients than in the control and HV + THAM groups. This occurred only in patients with a motor score of 4-5. At 12 months posttrauma this difference was not significant (p = 0.13). Biochemical data indicated that hyperventilation could not sustain alkalinization in the CSF, although THAM could. Accordingly, cerebral blood flow (CBF) was lower in the HV + THAM group than in the control and HV groups, but neither CBF nor arteriovenous difference of oxygen data indicated the occurrence of cerebral ischemia in any of the three groups. Although mean ICP could be kept well below 25 mm Hg in all three groups, the course of ICP was most stable in the HV + THAM group. It is concluded that prophylactic hyperventilation is deleterious in head-injured patients with motor scores of 4-5. When sustained hyperventilation becomes necessary for ICP control, its deleterious effect may be overcome by the addition of THAM.

Original languageEnglish (US)
Pages (from-to)731-739
Number of pages9
JournalJournal of Neurosurgery
Volume75
Issue number5
StatePublished - 1991
Externally publishedYes

Fingerprint

Tromethamine
Hyperventilation
Craniocerebral Trauma
Randomized Controlled Trials
Intracranial Pressure
Cerebrospinal Fluid
Cerebrovascular Circulation
Vasoconstriction
Brain Ischemia
Control Groups
Buffers
Glasgow Outcome Scale
Glasgow Coma Scale
Wounds and Injuries
Acidosis
Ventilation
Head
Oxygen

Keywords

  • cerebral blood flow
  • head injury
  • hyperventilation
  • intracranial pressure
  • outcome
  • tromethamine

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

Cite this

Muizelaar, J. P., Marmarou, A., Ward, J. D., Kontos, H. A., Choi, S. C., Becker, D. P., ... Young, H. F. (1991). Adverse effects of prolonged hyperventilation in patients with severe head injury: A randomized clinical trial. Journal of Neurosurgery, 75(5), 731-739.

Adverse effects of prolonged hyperventilation in patients with severe head injury : A randomized clinical trial. / Muizelaar, Jan Paul; Marmarou, A.; Ward, J. D.; Kontos, H. A.; Choi, S. C.; Becker, D. P.; Gruemer, H.; Young, H. F.

In: Journal of Neurosurgery, Vol. 75, No. 5, 1991, p. 731-739.

Research output: Contribution to journalArticle

Muizelaar, JP, Marmarou, A, Ward, JD, Kontos, HA, Choi, SC, Becker, DP, Gruemer, H & Young, HF 1991, 'Adverse effects of prolonged hyperventilation in patients with severe head injury: A randomized clinical trial', Journal of Neurosurgery, vol. 75, no. 5, pp. 731-739.
Muizelaar, Jan Paul ; Marmarou, A. ; Ward, J. D. ; Kontos, H. A. ; Choi, S. C. ; Becker, D. P. ; Gruemer, H. ; Young, H. F. / Adverse effects of prolonged hyperventilation in patients with severe head injury : A randomized clinical trial. In: Journal of Neurosurgery. 1991 ; Vol. 75, No. 5. pp. 731-739.
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