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Objective: To observe influence of escharectomy during and after burn shock stage upon the changes in plasma ET and NO., Methods: 35% TBSA full-thickness burn was produced in pigs, which were divided into two groups. Group S was a group undergoing escharectomy during burn shock stage at 24 h postburn. Group C was a group receiving escharectomy at 96 h after injury. ET and NO were determined and ET/NO was calculated., Results: The levels of ET and NO were higher after injury than before injury in both groups. The level of ET was lower significantly in group S than in group C from 96 h postburn on. The level of NO was higher in group S than in group C. The ET/NO was lower in group S than in group C from PBH 24 on., Conclusion: Escharectomy during burn shock stage was beneficial in reducing injury of endothelial cells, decreasing exudation and edema, decreasing tissue hypoxia and improving microcirculation.

The changes in microcirculation and the level of plasma TNF in rat at the early stage of burn shock were measured, and the effects of Polygonum cuspidatum (PC) on above mentioned changes were observed. It was shown when the level of plasma TNF was increased, the number of adhesive leukocytes on venule wall was increased and the number of open capillaries were reduced significantly, and there were apparent aggregation of leukocytes and injury in lungs. The level of plasma TNF and the number of adhesive leukocytes were nearly normal, and the degree of aggregation of leukocytes and injury of lungs were attenuated by giving PC. The present study showed that the level of elevated plasma TNF in the early stage of burn shock was directly correlated with the adherence of leukocytes and the closing of capillaries. The administration of PC could apparently inhibit the increase of leukocytes, and at the meantime, attenuate the adherence of the neutrophils and injury of the lung. The results confirmed that the elevation of plasma TNF might be involved in the development of adherence of neutrophils and the disturbances of microcirculation in burn shock.

The dynamic properties of membrane protein are closely correlated to the membrane functions in erythrocytes. The anion transport function of band 3 protein, the constituents and the translational diffusion of membrane protein was detected in 25% TBSA burn rats. The changes in membrane protein SH were investigated by using the spin label of 3-maleimide-proxyl. The results showed that, in delayed fluid resuscitation group after burn shock, membrane crosslinking protein appeared in erythrocytes, the function of band 3 protein was damaged, the recovery time after fluorescence photobleaching of membrane protein was obviously prolonged, and the ratio of peak heights of strong to weak immobilization was increased, especially in the six-hour delayed resuscitation group, suggesting that the ischemia-reperfusion injury was more serious during the early shock stage. The authors believe that the results may represent the mechanism of damage biological membrane after burns. The alterations of membrane properties caused by free radicals play an important role in erythrocyte injury.

The anion transport property is the one of the most important functions of the erythrocyte. In this paper a new method is used to measure the NO2- and Cl- ions transport across the erythrocyte membrane in burned rats. It was found that the NO2- and Cl- transport rate across erythrocyte membrane became slower during shock stage in burned rats, being contrary to the results found in heat-treated erythrocytes in vitro. By using a specific inhibitor of anion transport, DIDS, it was shown that the abnormality of NO2- transport across the erythrocyte membrane in burned rats is due probably to a damage of extracellular domain of band 3 protein. The authors consider that the influence of membranotoxic factors and the disturbance of energy metabolism during burn shock stage are accounted for all the noticed alterations.

Sixty seven burn patients (TBSA > 30%) were entered in a prospective study. Among them, twenty seven experienced delayed fluid resuscitation (DFR group) and the rest had early resuscitation (non-DFR group). Oxygen free radical (OFR) content in the blood was measured with ESR technic, and levels of blood SOD, blood GSHpx, serum MDA were also determined. The results showed: 1 The morbidity and mortality of burn shock and MSOF were higher in DFR group as compared with non-DFR group. 2 There was a significant increase of blood OFR content subsequent to resuscitation in DFR group as compared with that in non-DFR group. 3 The level of MDA in the serum of patients with burn shock was higher in DFR group than that in non-DFR group. 4 In DFR group, the level of serum MDA is higher in patients who developed MSOF as compared with that in patients who did not develop MSOF. The data indicated that DFR augmented the morbidity and mortality of burn shock and MSOF, in which OFR might play a role.

An analysis of serum free amino acid profiles in 8 patients dying from major burns revealed that free amino acid began to decrease in shock period, decrease 31.12% in infection period and 41.3% before death in comparison with the control group. The amount of BCAA-also decrease 36.27% in infection period and 56.83% before death. If the serum free amino acid in major burn drops steadily, the prognosis will be worse.