Barmaki Babak, Nasimi Ali, Khazaei Majid
Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
J Res Med Sci. 2011 Sep;16(9):1168-75.
Hypertensive patients have higher morbidity and mortality from hemorrhage. In this study, we investigated hemodynamic responses and serum nitrite concentrations during graded hemorrhagic shock and resuscitation in hypertensive (HT) and normotensive (NT) rats.
Thirteen male rats were divided into two groups, namely HT (n = 6) and NT (n = 7). Hypertension was induced by deoxycorticosterone acetate (DOCA)-salt method in uninephrectomized rats. After 8 weeks, graded hemorrhagic shock was induced during 34 minutes in four steps separated by 8-minute intervals (totally 16 ml/kg). The animals were kept in this condition for 120 minutes (shock period). Then, they were resuscitated with blood withdrawal. Mean arterial pressure (MAP) and heart rate (HR) were measured throughout the experiment. Blood samples were taken before and after shock induction and at the end of the shock period.
HT rats experienced more MAP and HR reduction during the shock period and less improvement of hemodynamic response after resuscitation compared with the NT group (p < 0.05). The survival rate 72 hours post-hemorrhage in the HT group was significantly lower than the NT group (16.7% vs. 71.4%, respectively) (p < 0.05). Serum nitrite level in HT animals was lower than the NT group (2.45 ± 0.18 vs. 3.35 ± 0.26 ΅mol/lit, respectively; p < 0.05). In addition, it increased during the shock period in both NT and HT groups (p > 0.05).
More reduction of MAP after hemorrhagic shock, less improvement of MAP and HR after resuscitation and low survival rate in HT animals suggested the impairment of cardiovascular system adaptation of HT animals during blood loss and it should be considered in management of hypertensive subjects.
高血压患者因出血导致的发病率和死亡率更高。在本研究中，我们调查了高血压（HT）大鼠和正常血压（NT）大鼠在分级失血性休克及复苏过程中的血流动力学反应和血清亚硝酸盐浓度。
将13只雄性大鼠分为两组，即HT组（n = 6）和NT组（n = 7）。通过醋酸脱氧皮质酮（DOCA）-盐法在单侧肾切除的大鼠中诱导高血压。8周后，在34分钟内分四个步骤诱导分级失血性休克，间隔8分钟（共16 ml/kg）。动物在此状态下维持120分钟（休克期）。然后，通过回输血液进行复苏。在整个实验过程中测量平均动脉压（MAP）和心率（HR）。在休克诱导前后以及休克期末采集血样。
与NT组相比，HT大鼠在休克期MAP和HR下降更多，复苏后血流动力学反应改善更少（p < 0.05）。HT组出血后72小时的生存率显著低于NT组（分别为16.7%和71.4%）（p < 0.05）。HT动物的血清亚硝酸盐水平低于NT组（分别为2.45 ± 0.18 vs. 3.35 ± 0.26 μmol/lit；p < 0.05）。此外，NT组和HT组在休克期血清亚硝酸盐水平均升高（p > 0.05）。
失血性休克后HT动物MAP下降更多，复苏后MAP和HR改善更少以及生存率低，提示HT动物在失血期间心血管系统适应性受损，在高血压患者的管理中应予以考虑。
