[Intrathoracic blood volume index as an indicator of fluid management in septic shock]

To investigate the value of intrathoracic blood volume index (ITBVI) monitoring in fluid management strategy in septic shock patients.

In a prospective study, 33 patients who were diagnosed to be suffering from septic shock in the intensive care unit (ICU) were enrolled . Seventeen patients who received pulse indicator continuous cardiac output (PiCCO) monitoring, and ITBVI was used as indicator of fluid management, were enrolled into ITBVI group; 16 patients who received traditional fluid management strategy [directed by central venous pressure (CVP)] were enrolled into control group. Acute physiology and chronic health evaluation II (APACHEII) score, sepsis related organ failure assessment (SOFA) score and vasopressor score were compared between 1 day and 3 days of treatment. The characteristics of fluid management were recorded and compared within 72 hours.

(1)In 3 days of treatment, APACHEII, SOFA and vasopressor score were significantly lower in ITBVI group compared with that of in 1 day of treatment[21.3±6.2 vs. 25.4±7.2, 6.1±3.4 vs. 9.0±3.5, 5 (0, 8.0) vs. 20.0 (8.0, 35.0), respectively, all P<0.01], whereas there were no changes in control group. (2)Although fluid output (ml) was higher in ITBVI group during 48-72 hours period (2 421± 868 vs. 1 721±934, P=0.039), there was no difference in fluid intake, fluid output or fluid balance (ml) within 0-72 hours between two groups (fluid intake: 9 918±137 vs. 10 529±1 331, fluid output : 6 035±1 739 vs. 5 827±2 897, fluid balance: 3 882±1 889 vs. 4 703±2 813, allP>0.05). (3)Comparing the fluid volume (ml) used for fluid replacement period, except that there was no significance in fluid challenge with colloid during 0-6 hours between two groups [ml: 250 (125, 500) vs. 250 (69,250), P>0.05], more fluid intake (ml) was found in ITBVI group [0-6 hours crystalloid: 250(150,250) vs. 125 (105,125), 6-72 hours crystalloid: 125 (125, 250) vs. 100 (56, 125), 0-72 hours crystalloid: 250(125, 250) vs. 125 (75, 125), 6-72 hours colloid: 125 (106, 250) vs. 75 (50, 125), 0-72 hours colloid: 200 (125, 250) vs. 100 (50, 125),all P<0.01].

Clinical picture in patients with septic shock is improved after 3 days of treatment than 1 day of treatment under fluid management directed by ITBVI, compared with by CVP. This improvement may be attributable to accurate assessment of preload and appropriate infusion rate in fluid challenge.