M. De Nadal et al., Cerebral hemodynamic effects of morphine and fentanyl in patients with severe head injury - Absence of correlation to cerebral autoregulation, ANESTHESIOL, 92(1), 2000, pp. 11-19
Citations number
40
Categorie Soggetti
Aneshtesia & Intensive Care","Medical Research Diagnosis & Treatment
Background: The current study investigates the effects of morphine and fent
anyl upon intracranial pressure and cerebral blood now estimated by cerebra
l arteriovenous oxygen content difference and transcranial Doppler sonograp
hy in 30 consecutive patients with severe head injury in whom cerebrovascul
ar autoregulation previously had been assessed.
Methods: Patients received morphine (0.2 mg/kg) and fentanyl (2 mu g/kg) in
travenously over 1 min but 24 h apart in a randomized fashion. Before study
, carbon dioxide reactivity and autoregulation were assessed. Intracranial
pressure, mean arterial blood pressure, and cerebral perfusion pressure wer
e repeatedly monitored for 1 h after the administration of both opioids, Ce
rebral blood flow was estimated from the reciprocal of arteriovenous oxygen
content difference and middle cerebral artery mean flow velocity using tra
nscranial Doppler sonography,
Results: Although carbon dioxide reactivity was preserved in all patients,
18 patients (56.7%) showed impaired or abolished autoregulation to hyperten
sive challenge, and only 12 (43.3%) had preserved autoregulation, Both morp
hine and fentanyl caused significant increases in intracranial pressure and
decreases in mean arterial blood pressure and cerebral perfusion pressure,
but estimated cerebral blood flow remain unchanged. In patients with prese
rved autoregulation, opioid-induced intracranial pressure increases were no
t different than in those with impaired autoregulation,
Conclusions: The authors conclude that both morphine and fentanyl moderatel
y increase intracranial pressure and decrease mean arterial blood pressure
and cerebral perfusion pressure but have no significant effect on arteriove
nous oxygen content difference and middle cerebral artery mean flow velocit
y in patients with severe brain injury, No differences on intracranial pres
sure changes were found between patients with preserved and impaired autore
gulation. Our results suggest that other mechanisms, besides the activation
of the vasodilatory cascade, also could be implicated in the intracranial
pressure increases seen after opioid administration.