Abstract
Blood is often collected from an arterial pressure monitoring kit connected with an intraarterial indwelling catheter for the purpose of examining plasma electrolytes, hematocrit titer and blood gas analysis during and after operation.
It is necessary to drain the amount of dead cavity between the site of puncture and site of collection before collecting the sample. But the amount of dead cavity may exert an influence on accuracy of test values. The authors studied the relationship between the amount of dead cavity and the amount of drain using values of electrolyte, hematocrit and blood gas analysis with commercially available infusion preparations. As a result, it was found that the amount of drain is required more than 4 times the amount if dead cavity for obtaining accurate values when a commercially available monitoring kit was used. In this study, a tube of a small diameter was used for the part of the dead cavity and accurate values were obtained with smaller amount of drain even where the amount of the dead cavity was the same. The above findings have revealed that in order to obtain accurate blood test values, we must have less amount of the dead cavity, and use a monitoring kit with a slender tube.
