Closed recirculatory spinal subarachnoid perfusion for determining CSF dynamics.

Journal of Neurosurgery (Impact Factor: 3.74). 04/1982; 56(3):368-72. DOI: 10.3171/jns.1982.56.3.0368
Source: PubMed


A new method for determining the rates of cerebrospinal fluid (CSF) production under nonsteady-state conditions, namely, closed recirculatory spinal subarachnoid perfusion, was used to determine the effect of enflurane on the rate of CSF production in dogs. Considerable variability in results was observed such that there was no statistical difference in rates of production among animals that received enflurane 2.2%, enflurane 2.2% and nitrous oxide 60% to 70%, enflurane 3.2% and nitrous oxide 60% to 70%, or nitrous oxide 60% to 70% (controls). Possible sources of variability were sought in additional studies using a modification of the new method, and in an in vitro model. The results were compared to those obtained using an established method for determining rates of CSF production, namely, open ventriculocisternal perfusion. It was concluded that the sources of variability in the closed recirculatory method relate in part to adherence of the fluorescein-conjugated albumin tracer to glass and other surfaces, and to uneven flow and distribution of the tracer in the recirculatory system. When the open ventriculocisternal perfusion method was used, consistent results were obtained, demonstrating that CSF production rate increased significantly in animals that received enflurane. The authors conclude that the new closed recirculatory method is less reliable than the classical open perfusion method.

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    ABSTRACT: Using the open ventriculocisternal perfusion method, rates of cerebrospinal fluid (CSF) production and reabsorption by bulk flow were examined in dogs anesthetized with either enflurane (2.2%) in nitrogen (60-70%) and oxygen, or nitrous oxide (60-70%) and enflurane (less than 0.2%) in oxygen (controls). The mean rate of CSF production increased significantly with enflurane (2.2%), from 0.055 +/- 0.020 ml/min (mean +/- SD) in controls to 0.082 +/- 0.033 ml/min (n = 12). After this initial increase of approximately 50%, the production rate decreased significantly by about 7.4%/h. When the expired concentration of enflurane was decreased from 2.2% to less than 0.2%, the mean rate of CSF production decreased to control values at 45-50 min. An intracerebral accumulation of CSF resulting from this enflurane-induced increase in CSF production may contribute in part to increased intracranial pressure when the dura is intact.
    Anesthesiology 11/1982; 57(4):255-60. DOI:10.1097/00000542-198210000-00001 · 5.88 Impact Factor
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    ABSTRACT: Recent information regarding the nature of bulk cerebrospinal fluid formation and absorption is reviewed, integrated with previous knowledge, and applied to the clinical setting.
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