Preliminary study on effect of intraoperative goal-directed fluid management on pulmonary function and oxygen dynamics in patients with severe burns

Objective To preliminarily investigate the effect of intraoperative goal-directed fluid management (GDFM) on pulmonary function and oxygen dynamics in patients with severe burns. Methods From February 2017 to May 2018, 30 patients admitted to Burn Department of our hospital with severe burns who met the criteria for inclusion and needed escharectomy and skin grafting were enrolled in this prospective randomized controlled trial. The patients were divided into group GDFM of 15 cases [14 males and 1 female, (45±14) years old] and conventional liquid management group of 15 cases [12 males and 3 females, (42±10) years old] according to the random number table. During escharectomy and skin grafting, volume of patients in group GDFM was managed according to the GDFM scheme, based on cardiac output index, stroke volume variation, stroke volume index, hemoglobin, central venous oxygen saturation (ScvO₂), and other parameters; volume of patients in conventional liquid management group was managed according to clinical experience and conventional liquid management scheme, based on mean arterial pressure, central venous pressure, urine output, hemoglobin, and other parameters. At post operation hour (POH) 1, 6, 12, and 24, arterial and venous blood was collected from patients of the two groups to determine the levels of extravascular lung water index (ELWI), global end-diastolic volume index (GEDI), oxygenation index, ScvO₂, central venous-to-arterial blood carbon dioxide partial pressure difference (Pcv-aCO₂), lactic acid, pH value, bicarbonate ion, and base excess routinely. Data were processed with Fisher′s exact probability test, t test, analysis of variance for repeated measurement, and least significant difference test. Results (1) The ELWI of patients in group GDFM was (4.3±1.1) mL/kg at POH 1, which was significantly lower than (6.5±3.6) mL/kg in conventional liquid management group (t=2.26, P<0.05). The ELWI levels of patients in group GDFM at POH 6, 12, and 24 were (6.8±2.2), (6.6±2.0), and (6.9±1.6) mL/kg, respectively, significantly higher than the level at POH 1 within the same group (P<0.01), and similar to (8.5±3.1), (7.8±2.3), and (8.0±3.5) mL/kg in conventional liquid management group (t=1.73, 1.53, 1.10, P>0.05). The GEDI levels between patients of the two groups were similar, and there was no significantly statistical difference between the two groups as a whole (treatment factor main effect F=2.35, time factor main effect F=0.44, interaction F=0.07, P>0.05). (2) The oxygenation index of patients in group GDFM was (350±78) mL/kg at POH 1, which was significantly higher than (259±109) mL/kg in conventional liquid management group (t=2.63, P<0.05). In conventional liquid management group, the oxygenation index of patients at POH 6 was significantly higher than that at POH 1, 12, or 24 (P<0.01). The ScvO₂ levels of patients in group GDFM at POH 1, 6, and 12 were 0.516±0.105, 0.679±0.121, and 0.713±0.104, respectively, which were significantly higher than 0.382±0.194, 0.545±0.194, and 0.595±0.191 in conventional liquid management group (t=2.35, 2.27, 2.10, P<0.05). The ScvO₂ levels of patients in the two groups at POH 6, 12, and 24 were significantly higher than those levels at POH 1 within the same group (P<0.01), and the ScvO₂ of patients in conventional liquid management group at POH 24 was significantly higher than that at POH 6 or 12 within the same group (P<0.05 or P<0.01). The Pcv-aCO₂ levels of patients in group GDFM were significantly lower than those in conventional liquid management group at POH 1 and 6 (t=2.55, 2.71, P<0.05). The Pcv-aCO₂ of patients in group GDFM at POH 12 was significantly lower than that at POH 6 or 24 within the same group (P<0.05). (3) The blood lactic acid levels and pH values between patients of the two groups were similar at POH 1, 6, 12, and 24 (t=0.89, 0.19, 0.26, 0.23; 1.55, 0.71, 0.77, 0.77, P>0.05). In conventional liquid management group, the blood lactic acid levels of patients at POH 6, 12, and 24 were significantly lower than the level at POH 1 within the same group (P<0.05), and the pH values of patients at POH 6, 12, and 24 were significantly higher than the value at POH 1 within the same group (P<0.05). The levels of bicarbonate ion and base excess between patients of the two groups were similar, and there were no significantly statistical differences between the two groups as a whole (treatment factor main effect F=0.06, 0.11, time factor main effect F=2.07, 1.59, interaction F=1.45, 0.91, P>0.05). Conclusions GDFM is helpful to improve the pulmonary function and oxygen dynamics in patients with severe burns in the short term after escharectomy and skin grafting. It has certain significance in preventing and reducing pulmonary edema and pulmonary complications in patients with severe burn after operation.