Holter electrocardiographa nd ECG R-R interval analyzer were compared as to the accuracy of measurement of R-R interval variations.ECG-simulated constant signals produced by Quartz clock (R-R interval : 1,000±0.5 msec.) were recorded for 60 sec. or continuous 60 R-R intervals with Holter electrocardiograph and R-R interval analyzer. After these recordings were repeated ten times, standard deviation (SD) and coefficient of variation (CV) of R-R intervals were calculated. Measurement of R-R intervals were also performed in young volunteers as well as in mechanically produced signals. Resting ECG was simultaneously recorded with Holter electrocardiograph and R-R interval analyzer and calculation of SD and CV was performed.SD and CV of ECG-simulated signals for Holter electrocardiograph were 4.2±0.6 msec. and 0.41±0.06%, respectively and those for R-R interval analyzer were 0.5±0.1 msec. and 0.05±0.01%, respectively.Coefficient of the corelation between Holter electrocardiograph and R-R interval analyzer was 0.952 in SD and 0.940 in CV, respectively.Coefficient of the corelation in the measurement for the human being between Holter electrocardiograph and R-R interval analyzer was over 0.9 and therefore Holter electrocardiograph could be useful for the measurement of R-R interval variations from the practical standpoint.
We investigated a method to sterilize digital clinical thermometers made of acrylonitrilebutadiene-styrene resin. To evaluate the bactericidal activity of disinfectants, we devised a method using a sterilized polyethylene bag. A clinical thermometer contaminated with bacteria was submerged in solution of disinfectant in a polyethylene bag. After varying period of contact the solution was poured off and replaced with 50 ml of SCDLP-broth (Soybean-casein digest broth with lecithine & polysorbate 80) to check for surviving bacteria; number of the survivours was counted by the spiral system (Spiral System Instruments Inc., U.S.A.).To sterilize clinical thermometers contaminated with 10^<3-7> cfu of Staphylococcus aureus, Escherichia coli, Pseudomonas cepacia, and Achromobacter xerosis, benzalkonium chloride was more effective than chlorhexidine gluconate at the same concentration. Almost all contaminating bactera were sterilized in a 0.2% solution of these disinfectants combined with 30% ethanol after 10 m of contact time.
It was found in the preceding study that the strain that showed the highest radiation resistance among the strains washed out of dializers not yet sterilzed was Bacillus megaterium and the D-value of its spore was about 40 percent higher than that of B.pumilus ATCC27142 spore. In the present study, bundles of hollow fibers were inoculated with spores of both the B.megaterium and the B.pumilus and D-values of the spores were measured to be 0.42_7 and 0.16_9 Mrad, respectively. The dializer is consisted of several materials. Sterilization effect of gamma-ray irradiation is the least for hollow fibers, because they contain glycerin. It is concluded that 10^6 sterility assurance is achieved by setting the sterilization dose at 2.0 Mrad, about eight times of the D-value for the B.megaterium under the condition that the number of contaminants per product is less than 100.