Yagi N, Leblanc M, Sakai K, Wright E J, Paganini E P
Department of Nephrology and Hypertension, Cleveland Clinic Foundation, OH 44195, USA.
Am J Kidney Dis. 1998 Dec;32(6):1023-30. doi: 10.1016/s0272-6386(98)70078-2.
Hypothermia is reported to increase intensive care unit (ICU) mortality. The heat loss that occurs during continuous renal replacement therapy (CRRT) favors the development of hypothermia. In an effort to assess the influence of CRRT on body temperature, we reviewed the records of 72 consecutive ICU patients treated with CRRT and further prospectively studied the temperature in the inlet and outlet lines for blood and dialysate of 27 other patients at various flow settings during continuous venovenous hemodialysis (CVVHD). Among the 72 retrospective cases, 36 episodes of hypothermia (core body temperature <35.5 degrees C) occurred and persisted for a mean of 2.6+/-1.8 days. It was more frequent during venovenous than arteriovenous modalities (31 of 67 v5 of 20, respectively); no patients developed hypothermia during arteriovenous slow continuous ultrafiltration (AVSCUS), whereas 48% of the patients undergoing CVVHD became hypothermic, occurring earlier in the therapy course (days 2 to 4). Mean arterial pressure (MAP) tended to increase after CRRT initiation, but absolute changes were not statistically significant. In the prospective arm, the CVVHD circuit temperatures were directly measured. Whereas no attempt was made to change body temperature, stepwise changes in blood (Qb) and dialysate flow rate (Qd) produced venous circuit temperature changes: the higher the Qb, the smaller the arteriovenous temperature differences independent of changes in Qd (P < 0.001). Also, venous circuit temperature varied directly with Qd at fixed Qb (P < 0.001). This relationship also held for temperature conversion to lost energy units per minute. Using room temperature dialysate, CRRT may significantly lower patients' core temperatures. Although the clinical significance of this effect is not clear at this point, energy loss during CVVHD may be important in hemodynamic stability or patient prognosis.
据报道，体温过低会增加重症监护病房（ICU）的死亡率。持续肾脏替代疗法（CRRT）过程中发生的热量散失有利于体温过低的发展。为了评估CRRT对体温的影响，我们回顾了72例接受CRRT治疗的连续ICU患者的记录，并进一步前瞻性研究了另外27例患者在持续静脉-静脉血液透析（CVVHD）期间不同血流设置下血液和透析液进出线路的温度。在72例回顾性病例中，发生了36次体温过低事件（核心体温<35.5摄氏度），平均持续2.6±1.8天。在静脉-静脉模式下比动脉-静脉模式更频繁（分别为67例中的31例对20例中的5例）；在动脉-静脉缓慢持续超滤（AVSCUS）期间没有患者出现体温过低，而接受CVVHD的患者中有48%出现体温过低，且在治疗过程中更早出现（第2至4天）。CRRT开始后平均动脉压（MAP）有升高趋势，但绝对变化无统计学意义。在前瞻性研究中，直接测量了CVVHD回路温度。尽管未尝试改变体温，但血液（Qb）和透析液流速（Qd）的逐步变化导致静脉回路温度变化：Qb越高，动静脉温差越小，与Qd的变化无关（P<0.001）。此外，在固定Qb时，静脉回路温度随Qd直接变化（P<0.001）。这种关系在将温度转换为每分钟能量损失单位时也成立。使用室温透析液，CRRT可能会显著降低患者核心体温。尽管目前这种影响的临床意义尚不清楚，但CVVHD期间的能量损失可能对血流动力学稳定性或患者预后很重要。
