An experimental study on changes of tissue oxygen partial pressure in Zusanli (ST36) acupoint and in its related organs in rabbits with acute respiratory distress syndrome / 中国中西医结合急救杂志

ABSTRACT

Objective To observe the characteristics of changes in tissue oxygen partial pressure in Zusanli (ST36) acupoint and related organs in acute respiratory distress syndrome (ARDS), and to clarify the correlation between oxygenation of local tissue and systemic oxygenation and the correlation between oxygen metabolism of acupoint tissues and related organ tissues.Methods Twenty healthy New Zealand white rabbits were selected and divided into an ARDS model group and a control group, according to random number table method, 10 in each group. Oleic acid (0.08 - 0.1 mL/kg) intravenous injection was used to replicate the ARDS animal model. Only tracheotomy, mechanical ventilation, insertion of arterial/venous catheter, etc other manipulations were conducted, and no oleic acid was injected in the control group. Tissue oximeter was used to determine the fraction of inspired oxygen (FiO2), when FiO2 was 0.21 and 1.00 respectively, the tissue oxygen partial pressure (PtO2) in Zusanli acupoint, stomach and liver was measured. Meanwhile, the blood gas analyses of arterial blood and mixed venous blood were carried out to calculate the oxygen extraction rate (O2ER).Results When FiO2 was equal to 0.21, the levels of PtO2 in Zusanli acupoint, stomach and liver of the ARDS model group were significantly higher than those of the control group in the same period; the partial pressure of oxygen arterial blood (PaO2), partial pressure of oxygen in mixed venous blood (PvO2), arterial oxygen saturation (SaO2), mixed venous oxygen saturation (SvO2) and O2ER of the ARDS model group were significantly lower than those of the control group over the same period. When FiO2 was equal to 1.00, PtO2, PaO2, SaO2 and O2ER in Zusanli acupoint, stomach and liver were increased compared with those when FiO2 was 0.21 in both groups, and the increase of PtO2 and O2ER in Zusanli acupoint, stomach and liver was more significant in the ARDS model group [PtO2 (kPa) Zusanli acupoint 16.75±2.12 vs. 13.80±1.83, stomach 16.45±1.33 vs. 13.35±1.25, liver 16.43±1.45 vs. 13.45±1.36, O2ER (36.14±0.97)% vs. (30.81±1.01)%]; the increase of PaO2, SaO2 and SvO2 was more significant in the control group [PaO2 (mmHg, 1 mmHg = 0.133 kPa) 682.02±50.32 vs. 159.32±40.17, SaO2 1.00±0.00 vs. 0.98±0.01, SvO2 0.69±0.01 vs. 0.63±0.03, allP < 0.05]. The indexes under FiO2 0.21 compared to those under FiO2 1.00 in the same group, it was shown that when FiO2 1.00, PvO2 was increased in the ARDS model group, but decreased in the control group, the difference between the two groups being statistically significant (mmHg 36.00±2.83 vs. 42.50±1.70,P < 0.05). Besides, PtO2 in Zusanli acupoint was positively correlated to that in stomach (r = 0.963,P < 0.001).Conclusions When ARDS is under the condition of systemic oxygen delivery disorder, the demand of organ tissues for oxygen is significantly increased, but the oxygen utilization is impaired obviously, which is possibly related to the cellular mitochondrial dysfunction. There is good correlation between the tissue oxygen partial pressure of acupoint tissue and related organ tissue. The detection of oxygen in acupoint tissue has important guidance significance for monitoring the oxygen metabolism of related organ tissues.