重症监护病房患者低磷血症的发生及对预后的影响

The occurrence of hypophosphatemia and its prognostic value in intensive care unit patients

目的调查重症监护病房（ICU）患者低磷血症的发生情况，研究不同血磷水平对患者预后的影响。方法观察2010年4月至11月入住盛京医院ICU147例患者的血磷水平及低磷血症的发生率，比较轻、中、重度血磷水平患者间急性生理学与慢性健康状况评分系统Ⅱ（APACHEⅡ）评分、住ICU时间、主要实验室指标以及病死率的差异；比较生存和死亡患者住ICU期间血磷的变化。建立血磷水平与是否存活患者之间的受试者工作特征曲线（ROC曲线），探讨血磷水平对预测患者预后的意义。结果77．6％的患者在入住ICU期间出现低磷，轻度21例、中度70例、重度23例，其中63．3％的患者出现中至重度的低磷；显著低磷的患者不仅APACHEⅡ评分（分）较高（轻度18．2±6．0，中度21．4±7．6，重度25．6±8．8，正常18．9±8．8），呼吸机使用时间（d）延长（轻度6．6±5．1，中度11．3±9．5，重度15．7±10．4，正常6．7±5．9），住ICU时间（d）较长（轻度9．7±6．4，中度10．6±8．2，重度18．9±13．1，正常9．9±7．1），而且病死率随之升高（轻度14．3％，中度25．7％，重度39．1％，正常9．1％）。ICU患者的总病死率（22．4％）与低磷的程度呈显著负相关（r=-0．225，P=0．01）；血磷〈0．40mmol／L时预测患者存活的敏感性为78．6％，特异性为51．5％，提示预后较差。结论大部分ICU患者血磷处于相对较低的水平。ICU患者容易合并低磷血症，重度低磷提示ICU患者预后较差。

Objective To investigate the occurrence of hypophospatemia in intensive care unit （ICU） patients, and to study the influence of different levels of phosphorus on the prognosis of patients. Methods One hundred and forty-seven patients admitted to Shengjing Hospital during April to November in 2010 were enrolled. The serum phosphrous level was measured consecutively, and the incidence of hypophosphatemia was observed. Acute physiology and chronic health evaluation Ⅱ （APACHE Ⅱ ） score, length of ICU-stay, the main laboratory findings and mortality were compared among patients with different serum phosphate levels. Receiver operating characteristic curve （ROC curve） was plotted according to the serum phosphate level and the survivability of patients to study the prognostic value of serum phosphate level in the ICU patients. Result A large number of ICU patients （77.6%） had developed hypophosphatemia, mild in 21, midrange in 70, and marked in 23, amounting to 63.3% of patients suffering from medium and marked hypophosphatemia. The APACHE Ⅱ score, duration of artificial ventilation （days）, length of ICU-stay （days） as well as mortality rate were higher in hypophosphatemia patients compared with those of the normal group （APACHE Ⅱ score： mild 18.2 ± 6.0, midrange 21.4 ± 7.6, marked 25.6 ± 8.8, normal 18.9 ± 8.8; length of artificial ventilation： mild 6.6 ± 5.1, midrange 11.3 ± 9.5, marked 15.7 ± 10.4, normal 6.7 ± 5.9; length of ICU-stay： mild 9.7 ±6.4, medium 10.6±8.2, marked 18.9 ±13.1, normal 9.9±7.1; mortality rate： mild 14.3%, medium 25.7%, marked 39.1%, normal 9.1% ）. The mortality of ICU patients （22.4%） was negatively correlated with the degree of hypophosphatemia （r=-0.225, P=0.01 ）. The serum phosphate level had a prognostic value when it was less than 0.40 mmol/L, with sensitivity of 78.6%, specificity of 51.5%. Conclusions For most of ICU patients, the serum phosphorus is at a relatively low level. ICU patients have multiple risk factors to develop hypophosphatemia and severe hypophosphatemia is a predictor of a poor prognosis.