Yin Ze-gang, Huang Yue-sheng, Li Bai-xing
Institute of Burn Research, Southwest Hospital, State Key Laboratory of Trauma, Burns and Combined Injury, the Third Military Medical University, Chongqing 400038, China.
Zhonghua Shao Shang Za Zhi. 2010 Feb;26(1):10-3.
To investigate the instant changes in heart function and organ blood flow, and their relations in rats at early stage of severe burn.
Thirty-six SD rats were divided into sham injury group (S, n = 6) and burn group (B, n = 30) according to the random number table. Rats in B group were subjected to 30% TBSA full-thickness burn. Five time points for observation: 10 and 30 minutes, and 1, 3, and 6 hour (s) post injury (PIM/H) were set up, with 6 rats at each time point. Rats in S group were sham scalded with 37 degrees C warm water. Hemodynamics indexes including heart rate (HR), mean artery pressure (MAP), left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), LV + or - dp/dt max were determined. Blood flow of heart, brain, kidney, spleen, stomach, and ileum was determined respectively with fluorescent microspheres method. The correlation between LV + or - dp/dt max and myocardial blood flow was analyzed.
(1) Compared with those of S group, HR in B group decreased gradually after injury; MAP, LVSP, LV +dp/dt max, LV -dp/dt max and myocardial blood flow in B group decreased obviously at PIM 10 (with F value respectively 12.062, 12.629, 11.066, 18.374, 9.468, and P values all below 0.01). Among them, myocardial blood flow decreased from (6.8 + or - 0.8) mL x min(-1) g(-1) to (2.6 + or - 0.5) mL x min(-1) x g(-1). Above-mentioned indexes increased gradually as the time after injury went on, with the highest values (except for LV +dp/dt max) observed at PIH 1, which decreased again later, with values at PIH 3 and 6 significantly lower than those in S group (the same F values as above, P values all below 0.01). There was no obvious difference in LVEDP between S group and B group at each time point (F = 1.205, with P values all above 0.05). (2) Compared with those of S group, blood flow of kidney, spleen, stomach, and ileum of rats in B group at PIM 10 declined obviously (with F value respectively 22.694, 20.856, 12.653, 7.293, P < 0.05 or P < 0.01), but the decline range was smaller than that in heart. The lowest values of above-mentioned indexes were observed at PIH 1 or PIH 3. Brain blood flow of rats in B group at each time point was close to that in S group (F = 1.812, with P values all above 0.05). (3) The correlation coefficient r between LV +dp/dt max, LV -dp/dt max and myocardial blood flow was respectively 0.651 and 0.617, showing significant positive correlation (with t value respectively 4.456 and 4.222, and P values all below 0.01).
The myocardial ischemia and decrease in cardiac function may occur in a very short time after severe burn (PIM 10). The rapid decrease of heart blood flow plays an important role in the change in cardiac function. Myocardial damage and decrease of cardiac function may be one of the important factors result in the decline of blood flow in other organs.
探讨严重烧伤大鼠早期心功能及器官血流的即时变化及其关系。
将36只SD大鼠按随机数字表法分为假伤组（S组，n = 6）和烧伤组（B组，n = 30）。B组大鼠行30%总体表面积全层烧伤。设置5个观察时间点：伤后10分钟、30分钟、1小时、3小时和6小时，每个时间点6只大鼠。S组大鼠用37℃温水假烫伤。测定血流动力学指标，包括心率（HR）、平均动脉压（MAP）、左心室收缩压（LVSP）、左心室舒张末期压力（LVEDP）、左心室压力上升/下降最大速率（LV±dp/dt max）。分别采用荧光微球法测定心、脑、肾、脾、胃和回肠的血流量。分析LV±dp/dt max与心肌血流量之间的相关性。
（1）与S组比较，则B组伤后HR逐渐降低；B组伤后10分钟时MAP、LVSP、LV +dp/dt max、LV -dp/dt max及心肌血流量明显降低（F值分别为12.062、12.629、11.066、18.374、9.468，P值均<0.01）。其中，心肌血流量从（6.8±0.8）ml·min-1·g-1降至（2.6±0.5）ml·min-1·g-1。上述指标随伤后时间延长逐渐升高，伤后1小时达最高值（LV +dp/dt max除外），随后又下降，伤后3小时和6小时的值显著低于S组（F值同上述，P值均<0.01）。各时间点S组与B组LVEDP比较差异无统计学意义（F = 1.205，P值均>0.05）。（2）与S组比较，B组大鼠伤后10分钟时肾、脾、胃和回肠血流量明显下降（F值分别为22.694、20.856、12.653、7.293，P<0.05或P<0.01），但下降幅度小于心脏。上述指标最低值出现在伤后1小时或3小时。B组大鼠各时间点脑血流量与S组接近（F = 1.812，P值均>0.05）。（3）LV +dp/dt max、LV -dp/dt max与心肌血流量的相关系数r分别为0.651和0.617，呈显著正相关（t值分别为4.456和4.222，P值均<0.01）。
严重烧伤后极短时间内（伤后10分钟）即可发生心肌缺血和心功能降低。心脏血流量迅速减少在心脏功能变化中起重要作用。心肌损伤和心功能降低可能是导致其他器官血流量下降的重要因素之一。
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