Swaminathan R, Bradley J A, Hill G H, Morgan D B
Postgrad Med J. 1979 Dec;55(654):858-61. doi: 10.1136/pgmj.55.650.858.
The loss of nitrogen after surgery is said to be related to body size as well as to the magnitude of the metabolic effects of surgery. Urine nitrogen should be 'corrected' for body size before it can be taken as a guide to the severity of surgery in the individual. Twenty-three patients were studied after elective abdominal surgery of moderate severity, when they were having only 3 litres of dextrose saline daily. The 24-hr urine nitrogen excretion (mean of days 3 and 4) was correlated with 3 indices of body size, body weight (r = 0.614), fat-free mass (r = 0.743) and 24-hr creatinine excretion (r = 0.780). Nitrogen excretion was corrected for body size by calculating the ratio of nitrogen to each index. For each index the s.d. of this corrected nitrogen excretion at the mean value of the index was less than the s.d. of the uncorrected data. The nitrogen : creatinine ratio in an untimed urine sample was closely related to the ration in the 24-hr urine (r = 0.914). These results demonstrate that nitrogen excretion after surgery is related to body size and can be corrected for body size by calculating the nitrogen : creatinine ratio in an untimed urine.
术后氮的丢失据说是与身体大小以及手术代谢效应的程度有关。在将尿氮作为个体手术严重程度的指标之前，应根据身体大小对其进行“校正”。对23例择期接受中等严重程度腹部手术的患者进行了研究，这些患者每天仅接受3升葡萄糖盐水。24小时尿氮排泄量（第3天和第4天的平均值）与3个身体大小指标相关，即体重（r = 0.614）、去脂体重（r = 0.743）和24小时肌酐排泄量（r = 0.780）。通过计算氮与每个指标的比值来校正身体大小对氮排泄的影响。对于每个指标，在校正后的氮排泄量的平均值处，其标准差小于未校正数据的标准差。随机尿样中的氮：肌酐比值与24小时尿中的比值密切相关（r = 0.914）。这些结果表明，术后氮排泄与身体大小有关，并且可以通过计算随机尿样中的氮：肌酐比值来校正身体大小对氮排泄的影响。
