Deitel M, Thompson D A, Saldanha C F, Ramshaw P J, Patterson M C, Pritzker K P
Can Med Assoc J. 1984 Apr 15;130(8):1007-11.
A pink coating on the inner surface of plastic urinary tubing, which gave the impression that the urine was pink, had frequently been noted 4 to 24 hours following gastric partitioning by means of a stapler in morbidly obese patients. A study was therefore done in 187 such patients as well as in 14 patients of normal weight who had undergone abdominal surgery of comparable magnitude. Postoperatively "pink urine" was observed in 32% of the obese patients but in none of the nonobese patients; however, a pink sediment remained following centrifugation of urine collected postoperatively from all the obese patients. Microscopy of this sediment showed crystals of uric acid dihydrate; these were infrequent in the preoperative specimens but present in high concentration in the postoperative specimens, particularly those of "pink urine". X-ray diffraction analysis confirmed the nature of the crystals. Preoperatively the obese patients had high-normal serum levels of uric acid. Postoperatively in all the groups of patients the serum levels of uric acid decreased while the urine levels and the urinary clearance of uric acid increased; the last two values, however, were significantly greater, both preoperatively and postoperatively, in those who were morbidly obese. Compared with the patients who did not have "pink urine" the patients with "pink urine" were significantly more obese and had a significantly lower postoperative urine pH. The latter also had a marked postoperative increase in urine osmolality and were the only patients to have a significant postoperative decrease in urine output. Thus, the pink colour of this group's urine was attributed to precipitation of uric acid crystals, fostered by a decrease in pH and an increase in concentration of the urine.
病态肥胖患者在使用吻合器进行胃分隔术后4至24小时，经常会注意到塑料尿管内表面有一层粉红色涂层，这给人尿液呈粉红色的印象。因此，对187例此类患者以及14例体重正常且接受了类似规模腹部手术的患者进行了一项研究。术后，32%的肥胖患者出现了“粉红色尿液”，而体重正常的患者均未出现；然而，对所有肥胖患者术后收集的尿液进行离心后，仍有粉红色沉淀。对这种沉淀进行显微镜检查发现了二水合尿酸晶体；这些晶体在术前标本中很少见，但在术后标本中浓度很高，尤其是“粉红色尿液”的标本。X射线衍射分析证实了晶体的性质。术前，肥胖患者的血清尿酸水平略高于正常。术后，所有患者组的血清尿酸水平均下降，而尿液中尿酸水平和尿酸清除率均升高；然而，后两个值在病态肥胖患者术前和术后均显著更高。与没有“粉红色尿液”的患者相比，有“粉红色尿液”的患者明显更肥胖，术后尿液pH值明显更低。后者术后尿渗透压也显著升高，并且是唯一术后尿量显著减少的患者。因此，该组尿液的粉红色归因于尿酸晶体的沉淀，这是由尿液pH值降低和浓度增加促成的。
