Abstract: Objective To investigate the effect of fluid resuscitation guided by pulse contour cardiac output (PiCCO) monitoring technology on the organ function in extremely severe burn patients. Methods From May 2015 to March 2019, 52 patients with extremely severe burn hospitalized in Tongren Hospital of Wuhan University & Wuhan Third Hospital, meeting the inclusion criteria, were recruited to conduct a prospectively randomized control study. The patients were divided into PiCCO monitoring rehydration group (25 cases, 17 males and 8 females) and traditional rehydration group (27 cases, 20 males and 7 females) according to the random number table, with the ages of (47±9) and (49±8) years respectively. After admission, all the patients were rehydrated according to the rehydration formula of the Third Military Medical University during shock stage. In traditional rehydration group, fluid resuscitation of the patients was performed by monitoring the traditional shock indicators such as urine volume and central venous pressure, while PiCCO monitoring was performed in patients in PiCCO monitoring rehydration group, and the global end-diastolic volume index combined with the other relevant indicators of PiCCO monitoring were used to guide rehydration on the basis of the monitoring indicators of traditional rehydration group. The rehydration coefficients and urine volumes per kilogram of body weight per hour during the first and second 24 h post injury were compared between the two groups, which were compared with the corresponding rehydration scheme value of the Third Military Medical University (hereinafter referred to as the scheme value) at the same time. The total rehydration volumes within post injury hour (PIH) 8 and during the first and second 24 h post injury, the urine volumes per hour during the first and second 24 h post injury, and the levels of creatinine, urea nitrogen, lactate clearance rate, procalcitonin, creatine kinase isoenzyme (CK-MB) in blood and mean arterial pressure (MAP) on post injury day (PID) 1, 2, and 3 were measured. The incidence of complications, the application case number of mechanical ventilation, and the mechanical ventilation time within PID 28 were analyzed. Data were statistically analyzed with analysis of variance for repeated measurement, t test, Bonferroni correction, Mann-Whitney U test, chi-square test, and Fisher′s exact probability method test. Results During the second 24 h post injury, the rehydration coefficient of patients in traditional rehydration group was significantly higher than the scheme value (t=5.120, P<0.01). During the first and second 24 h post injury, the rehydration coefficients of patients in PiCCO monitoring rehydration group were significantly higher than the scheme values (t=3.655, 10.894, P<0.01) and those in traditional rehydration group (t=3.172, 2.363, P<0.05 or P<0.01). Within PIH 8, the total rehydration volumes of patients between the two groups were similar. During the first and second 24 h post injury, the total rehydration volumes of patients in PiCCO monitoring rehydration group were significantly higher than those in traditional rehydration group (t=4.428, 3.665, P<0.01). During the first and second 24 h post injury, the urine volumes per kilogram of body weight per hour of patients in traditional rehydration group were significantly higher than the schema values (t=4.293, 6.362, P<0.01), and the urine volumes per kilogram body weight per hour of patients in PiCCO monitoring rehydration group were significantly higher than the schema values (t=6.461, 8.234, P<0.01). The urine volumes per kilogram of body weight per hour and urine volumes per hour of patients in PiCCO monitoring rehydration group during the second 24 h post injury were significantly higher than those in traditional rehydration group (t=2.849, 3.644, P<0.05 or P<0.01). The creatinine levels of patients between the two groups on PID 1, 2, and 3 were similar. The urea nitrogen levels of patients in PiCCO monitoring rehydration group on PID 1, 2, and 3 were (6.8±1.5), (5.6±1.4), (4.4±1.4) mmol/L respectively, which were significantly lower than (8.6±1.8), (6.6±1.5), (5.5±1.4) mmol/L in traditional rehydration group (t=3.817, 2.511, 2.903, P<0.05 or P<0.01). The lactate clearance rates of patients in PiCCO monitoring rehydration group on PID 1, 2, and 3 were significantly higher than those in traditional rehydration group (t=2.516, 4.540, 3.130, P<0.05 or P<0.01). The procalcitonin levels of patients in PiCCO monitoring rehydration group on PID 2 and 3 were significantly lower than those in traditional rehydration group (Z=-2.491, -2.903, P<0.05). The CK-MB level of patients in PiCCO monitoring rehydration group on PID 3 was (35±10) U/L, which was significantly lower than (51±16) U/L in traditional rehydration group (t=4.556, P<0.01). The MAP levels of patients between the two groups on PID 1, 2, and 3 were similar. Within PID 28, the incidence of complications of patients in traditional rehydration group was significantly higher than that in PiCCO monitoring rehydration group (χ²=4.995, P<0.05), and the application case number of mechanical ventilation and the mechanical ventilation time of patients between the two groups were similar. Conclusions The use of PiCCO monitoring technology to guide the early fluid resuscitation of extremely severe burn patients is beneficial for accurate determination of the fluid volume required by the patients and reduction of organ injury caused by improper rehydration.