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Objective: To compare the effect of intravenous resuscitation with sodium pyruvate (Pyr) Ringer solution against lactated Ringer solution on hemodynamic and organ functions during shock stage in dogs with burn., Methods: 28 Beagle dogs were subjected to 50% total body surface area (TBSA) burn, and they were divided into three groups: burn injury without fluid resuscitation (NR, n=8), Ringer lactate solution (RL, n=10), and Pyr Ringer solution (RP, n=10). They were given intravenous fluid resuscitation according to Parkland formula 30 minutes after burn. The hemodynamics, organ functions and mortality were observed in conscious state before burn injury, and 2, 6, 8, 12, 24 hours after burn injury., Results: Within 24 hours after burn, all the dogs in NR group died, and those in RL and RP groups were all alive. At 2 hours after burn, the mean arterial pressure (MAP), cardiac index (CI), dp/dt max of left ventricular contractility were significantly reduced in NR, RL and RP groups compared with those before injury (MAP: 45.33±7.78 mmHg vs. 141.67±5.98 mmHg, 91.33±10.25 mmHg vs. 142.33±6.16 mmHg, 98.67±9.54 mmHg vs. 142.83±5.47 mmHg; CI: 8.17±0.83 mL×s(-1)×m(-2) vs. 48.34±3.33 mL×s(-1)×m(-2), 16.84±2.17 mL×s(-1)×m(-2) vs. 47.34±1.67 mL×s(-1)×m(-2), 19.00±1.50 mL×s(-1)×m(-2) vs. 47.34±1.33 mL×s(-1)×m(-2); dp/dt max: 426.83±51.91 mmHg/s vs. 1 372.50±39.61 mmHg/s, 594.00±88.23 mmHg/s vs. 1 363.83±44.92 mmHg/s, 645.00±66.82 mmHg/s vs. 1 395.83±19.49 mmHg/s, all P<0.05), and the systemic vascular resistance (SVR) and alanine transaminase (ALT), creatinine (Cr), serum MB isoenzyme of creatine kinase (CK-MB), diamine oxidase (DAO) were significantly higher (SVR: 1 322.50±36.37 kPa×s×L(-1) vs. 281.45±8.84 kPa×s×L(-1), 777.50±41.84 kPa×s×L(-1) vs. 289.72±6.70 kPa×s×L(-1), 571.40±40.01 kPa×s×L(-1) vs. 286.27±8.66 kPa×s×L(-1); ALT: 89.50±4.11 U/L vs. 40.57±3.63 U/L, 89.25±4.88 U/L vs. 37.92±2.62 U/L, 86.30±5.61 U/L vs. 38.47±3.50 U/L; Cr: 75.62±4.61 μmol/L vs. 41.58±2.78 μmol/L, 77.00±5.92 μmol/L vs. 46.55±3.17 μmol/L, 74.13±2.56 μmol/L vs. 45.65±1.83 μmol/L; CK-MB: 13.122±0.282 kU/L vs. 1.557±0.009 kU/L, 8.885±0.272 kU/L vs. 1.497±0.009 kU/L, 8.692±0.180 kU/L vs. 1.490±0.005 kU/L; DAO: 2.26±0.14 kU/L vs. 0.25±0.02 kU/L, 1.50±0.07 kU/L vs. 0.25±0.01 kU/L, 1.37±0.07 kU/L vs. 0.25±0.02 kU/L, all P<0.05). All parameters in NR group kept on worsening till death, while hemodynamic and organ functions of two intravenous resuscitation groups were gradually improved, CI, SVR and DAO in RP group were significantly superior to those of RL group from 2 hours on after burn (all P<0.05), and dp/dt max and CK-MB in RP group were significantly better than those of RL group from 6 hours on after burn (dp/dt max: 1,082.33±63.59 mmHg/s vs. 1,018.60±47.36 mmHg/s, CK-MB: 7,898.70±255.74 U/L vs. 8,438.70±442.00 U/L, all P<0.05), and MAP was significantly better than that of RL group at 6 hours (124.67±9.39 mmHg vs. 114.33±9.16 mmHg, P<0.05), and Cr was significantly better than that of RL group from 24 hours on after burn (53.42±4.99 μmol/L vs. 60.77±3.11 μmol/L, P<0.05)., Conclusions: The Pyr Ringer solution was superior to the Ringer lactate solution in improving hemodynamic and organ functions for intravenous resuscitation in dogs with 50%TBSA full thickness burn.

Objective: To explore the effects of blood, crystalloid and colloid on mesenteric microcirculation in rabbits of acute hemorrhagic shock., Methods: Hemorrhagic shock was induced in 28 anesthetized mechanically ventilated rabbits by withdrawing blood to a mean arterial blood pressure (MAP) of 40 mm Hg and maintained for 30 min. The animals were randomized into blank control group, whole blood resuscitation group, Ringer's solution resuscitation (RR) group and volume resuscitation (VR) group (n = 7 each). The data of vital signs, systemic hemodynamic parameters, arterial blood gas analysis and mesenteric microcirculation were collected at baseline, hemorrhagic shock (HS-0), resuscitation 0 min (Res-0) and resuscitation 30 min (Res-30). And side-stream dark field imaging (SDF) was employed to acquire the images of mesenteric microcirculation., Results: No significant difference existed in the basic status between 4 groups. MAP decreased to around 40 mm Hg in all groups. MAP increased significantly after active fluid resuscitation (P < 0.05). In addition to blank control group, total vascular density (TVD), perfused vessel density (PVD), proportion of perfused vessels (PPV) and microvascular flow index (MFI) significantly increased after active fluid resuscitation in the other three groups. TVD and PVD were significantly lower at Res-0 in VR than in RR (P < 0.05)., Conclusion: After acute hemorrhagic shock, fluid resuscitation with whole blood and Ringer's solution improves systemic hemodynamics. And the combined regimen of whole blood and Ringer's solution is better at restoring mesenteric microcirculation.

The sectional test was adopted in this study to investigate the corrosion of pure iron in 0.15 mol/L NaCl solution, Ringer solution, PBS(-) solution, SBF solution and M199 cell culture medium at three different times. The result shows that different mediums have different corrosion effects on pure iron. The arrangement according to the medium's corrosion ability from the strongest to weakest is 0.15 mol/L NaCl solution (Ringer solution), PBS(-) solution, SBF solution and M199 cell culture medium. The results of scanning electron microscopy and energy dispersive X-ray spectrum analyses show that the addition of HPO4(2-), H2POC4-, Ca2+, Mg2+, SO4(2-) and the organic component can inhibit the corrosion to some degree.

Objective: To investigate the effects of Ringer's solution (RS) or 6% hydroxyethyl saline (HES) on bacterial translocation and inflammation of the small intestine in rats with hemorrhagic shock., Methods: Fifty healthy male SD rats were randomly divided into the sham group (SHA group, n=10), the Ringer's solution group (RS group, n=20) and 6% hydroxyethyl saline group (HES group, n=20). Controlled hemorrhagic shock model was reproduced in RS and HES groups. Bacterial translocation to the liver, the content of tumor necrosis factor-alpha (TNF-alpha) in intestinal tissue, and the myeloperoxidase (MPO) activity in the intestinal tissue were determined and compared among the groups, and the pathologic changes in the small intestine were observed., Results: The mortality rate, bleeding volume and Chiu's scores were same in HES and RS groups (all P>0.05). Compared to SHA group, bacterial count and TNF-alpha level were increased significantly in HES and RS groups, and they were higher at 1 hour and lower at 24 hours in HES group than those in RS group. Compared to the SHA group, MPO activity increased at 1 hour in RS and HES groups, but no significant difference between the groups was found at 24 hours., Conclusion: RS prevents compromise of the intestinal barrier function better than the HES at 1 hour after fluid resuscitation. However, HES seems to be better in protecting the intestinal barrier function compared with RS at 24 hours after fluid resuscitation.

Objective: To investigate the effect of 6% hydroxyethyl starch (HES) and Ringer's solution (RS) on splanchnic perfusion in dogs with septic shock., Methods: Twenty-four mongrel dogs with septic shock induced by lipopolysaccharides (LPS) were randomly divided into two groups: HES group and RS group. Dogs of each group received an intravenous infusion of HES or RS (1 mlxkg(-1)xmin(-1)) for 60 minutes, followed by normal saline for 180 minutes with same infusion speed. Parameters of hemodynamics, oxygen dynamic, and splanchnic perfusion were monitored at 0, 30, 60, 120, 180, 240 minutes after basic measurements (pre-LPS)., Results: (1) After LPS infusion, mean arterial pressure (MAP) and cardiac index (CI) lowered significantly (P<0.05). Compared to that of 0 minutes, MAP and CI were elevated by fluid therapy in both groups, but there was no difference between HES and RS group. (2) Compared with pre-LPS, oxygen delivery (DO(2)) was reduced, arterial blood pH lowered and arterial lactate level increased markedly at 0 minutes (P<0.05). DO(2) increased by fluid therapy in both groups, but DO(2) was higher in HES group at the same time points (P<0.05). Compared to 0 minutes, arterial lactate levels were lowered at 180 minutes in both groups. (3) Mesenteric blood flow decreased after LPS infusion in all animals (P<0.05). Mesenteric blood flow increased after HES infusion, at the same time intramucosal pH (pHi) was elevated and Pg-aCO(2) decreased significantly (all P<0.05), but they showed no difference in RS group. At the same time, mesenteric blood flow and pHi was higher in HES group than that in RS group., Conclusion: Both HES and RS could improve MAP and DO(2) in dogs with septic shock, but the effect of HES was better than RS on splanchnic perfusion.

Objective: To investigate the effect of hyperoxic Ringer's solution on inhalation injury given at early postburn stage in rabbit., Methods: Seventy-seven rabbits were randomly divided into four groups, i.e. A (normal control, n = 5, without injury), B (n = 24, with Ringer's solution infusion for 10 days after injury), C (n = 24, with hyperoxic Ringer's solution infusion for 10 days after injury) and D (n = 24, without treatment after injury) groups. The rabbits in B, C and D groups were observed on 1 post injury day (PID), 2 PID, 3 PID, 5 PID, 7 PID and 10 PID, with 4 in each time points. The vital signs and survival rate were observed and the blood gas analysis, the WBC and PMN in the peripheral blood, ratio of wet/dry weight (W/D) of the lung tissue, the MDA, SOD contents in the pulmonary tissue, and the pulmonary pathomorphology were determined by corresponding methods., Results: The respiratory rate of the rabbits increased postburn, which was accompanied with gasping breath, flapping of nasal alae, frequent cough, and increased buccal and nasal secretion. Dry and wet rales were heard in the lungs after injury. The survival rate in D, B and C groups was 13.3%, 27.8% and 65.6%, respectively. Metabolic acidosis was identified in these groups by blood gas analysis. The indices of PaCO2, WBC, PMN, W/D, MDA in B, C and D groups were higher than those in A group in the order of D > B > C > A groups. While the pH, PaO2 value and SOD content in D group were lower than those in A group in the order of D < B < C < A groups (P < 0.05). Pathomorphological examination revealed that pulmonary volume increased after the injury with microscopic inflammatory changes in pulmonary tissue in B, C and D groups. While the extent and degree of injury in C group after the treatment of hyperoxic Ringer's solution were evidently less severe than those in other groups., Conclusion: Early administration of hyperoxic Ringer's solution during the early postburn stage could be beneficial to the management of inhalation injury.

Objective: To explore the dynamic postburn changes in rat hepatic function and the effects of hyperoxic Ringer's solution resuscitation on the function., Methods: One hundred and ninety Wistar rats of both sexes with body weight of 250 - 300 g were employed as the model and were divided into 6 groups as A, B, C, D, E and F groups as follows: normal control (A, n = 10), early resuscitation with Ringer's solution (B, n = 40), delayed resuscitation with Ringer's solution (C, n = 30), early resuscitation with hyperoxic Ringer's solution (D, n = 40), delayed hyperoxic Ringer's solution resuscitation (E, n = 30) and burn control (F, n = 40). Blood samples were drawn from the injured rats under anesthesia at 6, 12, 24 and 48 postburn hours (PBHs), and the serum contents of ALT, AST and MDA in these blood samples were determined. Hepatic tissue samples were also harvested at the same time and served histologically., Results: The plasma ALT level at 6 PBH in all groups was higher than that in A group (P < 0.05). There was significant difference of plasma ALT levels between hyperoxic Ringer's solution treatment group an other treatment groups (P < 0.05). And there was evident difference of plasma ALT levels between hyperoxic Ringer's solution treatment groups and other treatment groups (P < 0.05). The dynamic change in plasma AST was almost similar to that of ALT. The plasma MDA level was increased obviously after injury, especially in F group (highest level). Furthermore, the MDA level in C group was higher than that in B group. The plasma MDA levels in D and E groups were evidently lower than that in all other groups (P < 0.05). It was revealed by histological examination that there were different degrees of degeneration an necrosis of hepatocytes during early postburn stage, but less so in D group., Conclusion: Fluid resuscitation during early postburn stage with hyperoxic Ringer's solution could inhibit the production of oxygen free radicals and blunt lipid peroxidation, and it could also enhance the host tolerance to hypoxia and prevent hepatocytes from injury, thus hepatic function was protected.

Objective: To study the effects of different volumes of fluid resuscitation on hemorrhagic shock with pulmonary edema at high altitude in the unacclimated rat., Methods: One hundred and twenty-six SD rats transported to Lasa, Tibet, 3 760 meters above the sea level, were anesthetized one week later with sodium pentobarbital (30 mg/kg, intraperitoneal). Hemorrhagic shock with pulmonary edema model was induced by hemorrhage (50 mm Hg for 1 hour, 1 mmHg=0.133 kPa) plus intravenous injection of oleic acid (50 microl/kg). Experiments were then conducted in two parts. Sixty-three rats in part I were equally divided into nine groups (n=7): normal control, hemorrhagic shock control, hemorrhagic shock with pulmonary edema (HSPE) without fluid infusion, HSPE plus infusing lactated Ringer's solution (LR) with 0.5-, 1-, 1.5-, 2- or 3- fold volume shed blood, and 1 volume of LR plus mannitol (10 ml/kg). Hemodynamic parameters including mean arterial blood pressure (MAP), left intraventricular systolic pressure (LVSP) and the maximal change rate of intraventricular pressure rise or decline (+/- dp/dt max) were observed at 15, 30, 60 and 120 minutes after infusion, blood gases were measured at 30 and 120 minutes after infusion and the water content of lung and brain was determined at 120 minutes after infusion. In part II, additional 63 rats were used to observe the effect of different volumes of fluid resuscitation on survival time of HSPE rats., Results: 0.5 volume of LR infusion significantly improved MAP, LVSP and +/- dp/dt max, prolonged the survival time of HSPE animals (all P<0.01), while it did not increase the water content of lung and brain and had no marked influence on blood gases. One volume of LR infusion slightly improved hemodynamic parameters, prolonged the survival time and increased the water content of lung. More than 1 volume of LR infusion including 1.5-, 2- and 3- fold volume LR deteriorated the hemodynamic parameters and decreased the survival time of shocked animal, meanwhile they apparently increased the water content of lung. One volume of LR plus mannitol (10 ml/kg) infusion did not improve the hemodynamic parameters and blood gases; also it did not decrease the water content of lung., Conclusion: The tolerance to fluid infusion for the unacclimated animal subjected to hemorrhagic shock with pulmonary edema at high altitude is significantly decreased. 0.5-1 volume of LR infusion appears to be beneficial effect on resuscitation at high altitude, while over 1 volume of LR infusion would aggravate pulmonary edema and exacerbate fluid resuscitation effect.

Objective: To explore the effects of delayed resuscitation on burn shock with ringer's solution., Methods: Twelve mongrel dogs were randomly divided into control (S, n = 6) and treatment (LR, n = 6) groups. The dogs in LR group were inflicted by 35% TBSA III degree burn and were resuscitated with Lactate Ringer's solution. Urine output in amount of 1 ml.kg-1.h-1, and cardiac output at level of 70% approximately 80% of pre-burn level were referred for the modulation of the speed and amount of fluid infusion. The postburn changes of volumetric load, mean arterial pressure (MAP), LVSP +/- dp/dtmax, CI, DO2 and VO2 during the first 24 hours of resuscitation were observed., Results: The infusion amount of LR solution was 8.87 +/- 1.02 ml/kg per 1% TBSA during the first 24 hours of resuscitation, which was 1.2 times more than that with Parkland formula. Furthermore, the infusion fluid amount within the first 4 hours of resuscitation was (3.63 +/- 0.99) ml.kg(-1).1% TBSA-1, which was 41% of total amount within the first 24 hours. MAP, LVSP, +/- dp/dtmax, CI, DO2 and VO2 reached or approached the levels in S group within 2 hours of resuscitation., Conclusion: The infusion amount of Lactate Ringer's solution needed in delayed resuscitation was larger than that in early resuscitation. And the indices of hemodynamics and myocardial mechanics were improved obviously within 2 hours of resuscitation.