Frank E. Nulsen

Physiological effects of dimethyl sulfoxide on peripheral nerves: Possible role in pain relief

Abstract When DMSO is applied directly to a peripheral sensory nerve, it will initially block conduction in C fibers. If application is continued, it progressively blocks fibers from small to large. As small fibers are important for the recognition of noxious stimuli, the blockade of these fibers by DMSO may offer an explanation for the reported relief of pain following its application.

Alterations in Ventricular Fluid Pressure during Ketamine Anesthesia in Hydrocephalic Children

We studies ventricular fluid pressure changes in 26 hydrocephalic children following administration of ketamine. The increase in VFP previously found with intravenously administered ketamine was compared with changes after ketamine given intramuscularly, and the possible alteration of this increase with sedative premedicants was studies. Changing the route of administration did not change the time to peak VFP changes or the duration of pressure elevation. There was no demonstrable alteration of the increase in VFP by premedication with secobarbital, dorperidol, or diazepam in clinical dosage. We feel that acute rises of VFP may affect areas of marginal cerebral blood flow and may increase the risk of herniation of brain tissue.

Chronic Monitoring of Intraventricular Pressure in Children Using Telemetry: Engineering and Physiologic Aspects

Acute monitoring of intracranial pressure via external ventricular drainage systems carries low risk when the implantation is for short periods of time (usually less than ten days) (Smith and Alksne 1976). As the length of time the device is used increases, the risk of infection increases (Rekate 1976). During the period of monitoring the patient is continuously restricted in movement by the drainage system. There are certain pathologic States in which prolonged monitoring of intracranial pressure would be clinically useful. These include hydrocephalus, some metabolic encephalopathies, and patients with brain tumors undergoing chemotherapy. For these purposes the Electronics Design Center of the School of Engineering is developing a device for the continuous monitoring of intraventricular pressure by telemetry. This report will deal with the development of, and clinical experience with, this device.