Comparative Study of Cystometry in Patients under General and Spinal Anesthesia . |
Jae Kyu Jeon, Jung In Bae |
Department of Anesthesiology, Keimyung University School of Medicine, Taegu, Korea. |
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Abstract |
Voiding difficulty has been well documented as a complication after spinal anesthesia. This occurs somewhat more frequently after spinal anesthesia than after general anesthesia. However, the cause and mechanism of postspinal voiding difficulty has not been clarified, so in this study we have attempted to discover the mechanism of the voiding difficulty. Cystometry was performed on 30 healthy women who were scheduled for simple hystrectomy and the results were compared in three different groups. In the first group, cystometry was performed on 30 cases under only the premedication before the induction of anesthesia. In the second group, it waa performed on 14 cases under general anesthesia and in the 3 rd group, performed on 16 cases under spinal anesthesia. The results were as follows: 1) In the first group of 30 cases before anesthesia, the first voiding desire starts at approximately 150-250 ml (24 cases) and the average pressure of the bladder at the first voiding desire is approximately 5-10 cm H2O(19 cases). The volume at the maximum voiding desire is about 450-550ml(20 cases) and its pressure was 16-20cm H2O(12 patients). The average pressure tension curve of the cystometry was very similar to the normal one. 2) In the 2nd group of 16 cases under general anesthesia, measurement was not obtainable at the first and maximum voiding desire because they were under the effect of the anesthesia. The average pressure tension curve of the cystometry was lower than Group I (Fig. 1) and the critical volume which is designated as the volume at the point where the pressure of the bladder increased sharply in cystometry, was about 700ml which was larger than Group I.
3) In the 3 rd group of 16 cases, the cystornetry showed on the average pressure tension curve that the increase of the pressure was proportional to the volume in the bladder and no critical volume seems to be observed. It means that there is no contraction of the bladder muscle due to the paralysis of the sacral parasympathetic nerves which innervate the detrusor muacle of bladder. As a result of this study, we came to the conclusion that a cause of post-spinal urinary retension is the residual effect of local anesthetics prolonging the depression of the autonomic parasympathetic innervation system. These fibers from S2-S4 are very susceptible to analgesic solutions. |
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