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Biomedical subjects

F F Klein

Publications and source records attributed to F F Klein.

8 recordsLinked to original sources
PubMed1986

[Brain function and level of consciousness in fentanyl anesthesia in heart surgery].

The level of consciousness and the supply/demand ratio of oxygen in the brain was studied in anaesthetized patients undergoing open heart surgery. Anaesthesia was accomplished with intravenous fentanyl; 26 patients received 25 micrograms/kg and 24 patients received 50 micrograms/kg fentanyl. In addition only pancuronium bromide was administered for muscular relaxation; all patients were ventilated with 100% oxygen. The following measurements were made during induction and prior to cardiopulmonary bypass and in the first ten minutes of bypass: 1. EEG with the Klein EEG Analyzer. This instrument permits simultaneous analysis of frequency and amplitude while eliminating muscular artifacts. 2. Cerebral oxygen with the Niroscope. This instrument uses an infrared light beam through the brain to evaluate cerebral oxygen sufficiency. 3. Oxygen supply/demand ratio in the whole body, estimated from mixed venous oxygen saturation measured with a fiberoptic pulmonary artery catheter. Clinical unconsciousness occurred in all patients within about 30 s after the administration of fentanyl. Simultaneously the EEG showed a significant decrease in frequency and an increase in amplitude. With the Niroscope no change in oxygen supply and demand was seen in any patients. This is in contrast to previous studies with thiopental, where changes were seen. A slight increase in mixed venous oxygen saturation was observed. This indicates an increase in the total oxygen supply/demand ratio, probably due to decreased muscle metabolism induced by pancuronium bromide paralysis. From the end of induction until cardiopulmonary bypass a slight increase in cerebral electrical activity was observed; an additional increase occurred in the first ten minutes of bypass.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗
PubMed1985

The computer-based anesthetic monitors: the Duke Automatic Monitoring Equipment (DAME) system and the microDAME.

From 1972 to 1983 the Duke University Department of Anesthesiology designed, built, and maintained most of its own operating room patient monitoring equipment. Construction of a new hospital facility in 1980 provided the opportunity to design and test a new computer-based system, the Duke Automatic Monitoring Equipment (DAME) System. The system consist of microcomputer-based instrumentation on monitoring carts, which communicate with a central minicomputer that allows selection of different software monitoring packages based on the needs of the patient. Multiple problems, including frequent total monitoring failures during surgery, plagued the DAME System in its first year of operation. Despite resolution of many of these problems, user acceptance was poor because of the large size and weight of the monitoring carts, the inadequate quality of displayed physiological waveforms, and inability to overcome the difficulties of the man-machine interface. Because the remaining problems could not be rectified with the existing monitoring carts, a new generation of monitors was designed. The smaller, multiprocessor microDAME was designed to be as automatic and user tolerant as possible. It would omit much of the flexibility that had proved undesirable in the DAME system. When the microDAME was nearly completed, however, departmental research in that area ceased. It remains for others to apply our experiences to further improve operating room patient monitors.

Anesthesiology↗
PubMed1978

The EEMG--a practical index of cortical activity and muscular relaxation.

In a continuing study of the EEG as a monitor of cortical activity during anesthesia using a time-domain wave analyzer, the contamination of the EEG by scalp muscle activity was observed. A measure of this EMG activity was extracted from the combined EEG/EMG wave obtained from two electrodes placed over the left frontalis muscle and right mastoid process. Clinical work with this variable showed that the EMG can serve both as a reliable guide to patient muscular relaxation and an indicator of unacceptable muscle contamination of the EEG. This extracted variable in conjunction with the analyzed EEG has served as a valid indicator in the assessment of the anesthetic state. The system has been successfully employed in the management of nearly 1000 surgical patients.

Anesthesia, General↗
PubMed1976

A 4-channel telemetry system for hospital patient monitoring.

A 4-channel radio telemetry system has been designed and implemented for use in the operating room on patients undergoing surgery. 30 such systems are in daily use throughout the Duke University Medical Cener. Relative simplicity, long battery life and a DC-response capability are the important features of these systems. The four physiological channels used are; electroencephalogram, electrocardiogram, peripheral pulse, and arterial blood pressure.

Blood Pressure Determination↗