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Biomedical subjects

T Nissen

Publications and source records attributed to T Nissen.

26 records · Page 2Linked to original sources
PubMed1983

Topographic variations in alpha-adrenergic and cholinergic response in the pig renal pelvis.

The effect of alpha-adrenergic and cholinergic receptor stimulation is quantitatively analyzed in different regions of the pig pyeloureter. Smooth muscle strips from minor calyces, pelvis proper and ureter were investigated. Stimulation with potassium (127 mM) was used as reference. Both phenylephrine and carbachol caused a concentration-dependent increase in basal tone in the pelvis and the minor calyx. The maximum response obtained was significantly smaller in the pelvis than in the minor calyx. As compared to phenylephrine, the response to carbachol was negligible. The ureter showed a different behavior as compared to the minor calyx and pelvis. A constant basal tone could not be obtained and the tissue did not respond to potassium in a reproducible way.

Animals↗
PubMed1978

Temperature alarm for heated humidifiers.

In order to ensure a water content of between 30 and 40 mg/l in the inspiratory gases using a heated humidifier, the temperature in the delivery tube, near to the patient, must be between 30 and 37 degrees C. A low cost thermistor temperature alarm is described which indicates by means of different coloured lights if the temperature falls below 30 degrees C, lies between 30 and 37 degrees C, or if the temperature exceeds 37 degrees C. An alarm also sounds if temperatures above 37 degrees C occur. This device has been in use since 1974 and has proved reliable and time saving.

Humidity↗
PubMedDate not supplied

A water-insensitive ventilator alarm.

Most of the low-pressure ventilator alarms available have the pressure registration unit connected to the patient circuit by a narrow bore plastic tube. Condensed water in this tube will stop the correct function of the alarm in a few hours if the tube is placed after a heated humidifier. The pressure registration should be as close to the patient's tracheal tube as possible to monitor the pressure of the airway and hence a ventilator alarm with the pressure sensing unit in the patient circuit is described. The alarm has proved to be reliable, insensitive to water and very easy to adjust to maximum sensitivity.

Accident Prevention↗
PubMedDate not supplied

Continuous registration of cardiac output with a new computer system designed for hot-film anemometry: an in vitro study.

We have developed and improved a method for the continuous on-line registration of cardiac output. By measuring blood velocity with a hot-film anemometer probe in the pulmonary artery, cardiac output can be estimated by gated systolic integration of the velocity signals. The integrated value for a certain period can be converted to a cardiac output proportional value. A thermistor placed next to the velocity probe enables thermodilution measurement of cardiac output, which serves as in vivo and in situ calibration. In this paper an in vitro study of the method applied to pulsatile flow is presented. A good correlation was found between real flow and both the velocity method and the thermodilution method. Fluid temperature and changing stroke volume and/or pulse frequency had minimal influence on accuracy, whereas altered probe position required recalibration for the velocity method but not for the thermodilution method. The advantages of the velocity method for the measurement of cardiac output are: The continuous on-line monitoring of cardiac output. The need for the injection of only very small volumes of cold saline, as the frequency of thermodilution measurements is reduced.

Cardiac Output↗