MethodsA total of 48 Wistar rats were randomly divided into the cecal ligation and puncture (CLP) group, small-dose treatment group, medium-dose treatment group and large-dose treatment group, 12 rats in each group. The sepsis model was made by the CLP method, and dexmedetomidine was given respectively at the speed of 2.5 μg·kg-1·h-1, 5 μg·kg-1·h-1 and 10 μg·kg-1·h-1 to rats in small, medium and large-dose treatment groups through continuous tail vein pumping. The mean arterial pressure and heart rate at 1, 3, 5 h after CLP were recorded; arterial blood gas was measured at 3 h after CLP, including pH, partial pressure of carbon dioxide, partial pressure of oxygen, base excess in extracellular fluid, and levels of bicarbonate, total carbon dioxide, oxygen saturation and blood lactic acid; the death of rats in each group at 24 h was calculated.
ResultsThe heart rate and the level of mean arterial pressure in the four groups were significantly different (F=2.935, 3.862; P=0.005, 0.001). Compared with the CLP group, the mean arterial pressure of rats in small, medium and large-dose treatment groups decreased significantly at 1 h after operation (all P < 0.05), but there were no significant differences among the three groups at 3 h and 5 h after operation (all P > 0.05). However, the heart rate of rats in small, medium and large-dose treatment groups began to decrease at 3 h and 5 h after operation (all P < 0.05). The mean arterial pressure in the CLP group at 3 h and 5 h after operation was significantly lower than that at 1 h (all P < 0.05), while the heart rate of rats in the small, medium and large-dose treatment groups at 3 h and 5 h after operation was significantly lower than that at 1 h (all P < 0.05). The heart rate at 5 h after operation in the small and medium-dose treatment groups was significantly lower than that at 3 h (all P < 0.05). There were significant differences at the pH value [(7.27 ± 0.07), (7.17 ± 0.08), (7.12 ± 0.07), (7.13 ± 0.07)], partial pressure of carbon dioxide [(38 ± 8), (72 ± 21), (77 ± 24), (83 ± 16) mmHg], base excess in extracellular fluid [(-9.7 ± 3.9), (-3.2 ± 2.8), (-4.7 ± 3.4), (-2.0 ± 1.7) mmol/L], and levels of bicarbonate [(17.4 ± 3.3), (25.0 ± 2.7), (24.7 ± 4.2), (27.1 ± 1.7) mmol/L], total carbon dioxide [(18.6 ± 3.7), (27.1 ± 2.8), (26.9 ± 4.9), (29.6 ± 2.1) mmol/L], oxygen saturation [(97.8 ± 1.0)%, (97.2 ± 1.5)%, (93.9 ± 4.2)%, (94.4 ± 4.0)%] and blood lactic acid [(94.45 ± 4.01), (0.63 ± 0.66), (0.63 ± 0.43), (0.45 ± 0.38) mmol/L] in the four groups (F=21.902, 34.460, 30.096, 33.709, 33.988, 18.076, 39.916; all P < 0.05). In the same time, there was no significant difference in partial pressure of oxygen [(115 ± 17), (118 ± 23), (105 ± 19), (109 ± 22) mmHg; F=1.545, P > 0.05]. Compared with those in the CLP group, the pH value, partial pressure of carbon dioxide, base excess in extracellular fluid, bicarbonate, total carbon dioxide and blood lactic acid of rats in the small, medium and large-dose treatment groups were significantly different (all P < 0.05), and the oxygen saturation was significantly lower in the medium and large-dose treatment groups than in the CLP group (all P < 0.05). In addition, compared with the large-dose treatment group, the total carbon dioxide content and oxygen saturation in the small-dose treatment group and base excess in extracellular fluid in the medium-dose treatment group were significantly different (all P < 0.05). The proportional mortality indicator of the four groups (11/1, 9/3, 3/9, 2/10) was statistically significantly different (χ2=17.658, P=0.001), and it was significantly lower in the medium and large-dose treatment groups than in the CLP and small-dose treatment groups (all P < 0.008).
