Effects on Intracranial Pressure of Fentanyl in Severe Head Injured Patients
Despite opioids are routinely used for analgesia in head injured patients, the effects of such drugs on ICP and cerebral hemodynamics remain controversial. Cerebrovascular autoregulation (CAR) could be an important factor in the ICP increases reported aft
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© Springer-Verlag 1998
Effects on Intracranial Pressure of Fentanyl in Severe Head Injured Patients M. de Nadalt, A. Ausina 1, J. Sahuquillo 2, S. Pedraza\ A. Garnacho\ and V. A. Gancedo
1
Departments of 1 Anesthesiology, 'Neurosurgery, 1 Neuroradiology, and 4Neurotraumathology Intensive Care Unit, Vall d'Hebron University Hospitals, Barcelona, Spain
Summary Despite opioids are routinely used for analgesia in head injured patients, the effects of such drugs on ICP and cerebral hemodynamics remain controversial, Cerebrovascular autoregulation (CAR) could be an important factor in the ICP increases reported after opiod administration, In order to describe the effects on intracranial pressure of fentanyl and correlated such efects with autoregulation status, we studied 30 consecutive severe head injury patients who received fentanyl (211g/kg) intravenously over one minute, Prior to study, CAR was assessed. Monitoring included MAP, HR, SaO" ETCO" SjO, and ICP. Changes in cerebral blood flow (CBF) were estimated from relative changes in AVDO,. Patients mean GCS was 5.7 ± 1.7 (mean ± STD) and mean ICP on admission was 23.8 ± 16.3mmHg. Fentanyl caused significant increases in ICP and decreases in MAP and CPP, but CBF remained unchanged when estimated by AVDO,. In patients with preserved CAR (34.5%), opiod-induced ICP increase was greater (but not statistically significant) than in those with impaired CAR (65.5%). We conclude than fentanyl moderately increased ICP and decreased MAP and CPP. Our data suggests that in patients with preserved CAR, potent opioids could cause greater increases of ICP, probably due to activation of the vasodilatadory cascade. Keywords: CBF; fentanyl; head injury; opoids.
Introduction Synthetic opioids are routinely used for analgesia in severe head-injured patients as part of the management of increased intracranial pressure (ICP), However, the cerebrovascular effects of opioids remain controversial. Studies in laboratory animals and humans have shown increases, decreases or no change in cerebral blood flow (CBF) and/or ICP after opioid administration. Most of these studies found a concomitant decrease in mean arterial pressure (MABP) and recently, it has been suggested that systemic hypotension could in fact be responsible for
the increases in ICP observed after the administration of potent opioids such as fentanyl or sufentanil [2,11], In patients with low intracranial compliance and intact autoregulation, reduced MABP would be expected to result in vasodilation, increased blood volume and thus increased ICP, Cerebrovascular autoregulation (CAR), which is impaired in at least 50% of severe head injured patients [5,7], could be an important factor in the ICP increases reported after opioid administration, In order to investigate the role of CAR in opioid-induced cerebral hemodynamic changes, we studied the effect of fentanyl upon ICP and CBF in patients with severe head injury and high ICP in whom the status of autoregulatory mechanisms were previously assessed. Materials and Methods Afte
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