Experimental Observation On The Changes Of Blood Oxygen Saturation In Early Stage Of Rabbit OCS

OBJECTIVE To establish rabbit models of osteofascial compartment syndrome, and observe blood oxygen saturation,intracompartment pressure changes and pathological changes of muscle in the early stage of osteofascial compartment syndrome,and investigate the correlation between osteofascial compartmental pressure and oxygen saturation,and determine the feasibility of measuring oxygen saturation in the diagnosis of osteofascial compartment syndrome.METHODS Twenty-four healthy New Zealand white rabbits (2.3±0.3kg) were anesthetized with pentobarbital sodium. They were randomly divided into four groups, six rabbits in each group.By right leg wrapped in a tourniquet cuff inflated to 40-80 kPa the animal models of osteofascial compartment syndrome were established. We performed osteofascial compartmental pressure and both lower extremities pulse oxygen saturation measurements on four groups of rabbits that underwent 0 h(Group A),4h(Group B),6h(Group C) and 8 h(Group D) of pneumatic tourniquet application (PTA).Osteofascial compartmental pressure were measured by Whiteside method and both lower extremities pulse oxygen saturation value were measured by pulse oximete. After experiment, fasciotomy of rabbits right lower extremity was made and the anterior tibial muscle were undertook biopsy. All data of rach group were analyzed statistically using a single method pairwise comparisons (ie LSD method) for multiple comparison by SPSS (version 16.0),and two data sets of osteofascial compartmental pressure and oxygen saturation were bivariate correlation analyzed statistically.RESULTS A total of twenty-four rabbits were involved in the analysis of result.1.The average value of osteofascial compartmental pressure from Group A were (3.44±2.22) mmHg, Group B were (22.54±6.77) mmHg which did not meet the diagnostic criteria of osteofascial compartment syndrome. With the increase of time the average value of Group C and D increased to (32.77±7.13)mmHg and (37.39±5.67)mmHg which met the diagnostic criteria.The average value of right lower extremity oxygen saturation from Group A were (98.36±1.32)% which did not reach the diagnostic criteria of Hypoxia.Group B were(93.43±3.88)%,which were hypoxia. With the increase of time,the average value of Group C and D reduced to (85.45±5.68)%and(82.08±5.83)% which were moderate or severe hypoxia. Group B,C and D Date of osteofascial compartmental pressure and right lower extremity pulse oxygen saturation were compared with Group A, P<0.05, the difference was significant. The average value of left lower extremity oxygen saturation from Group A-D were(98.03±1.47)%,(97.79±0.79)%,(98.83±0.42)%&(97.89±1.02)%, which did not reach the diagnostic criteria of Hypoxia.2.Two data sets of oxygen saturation and osteofascial compartmental pressure were bivariate correlation analyzed. The result were R=-0.819 and correlation coefficient test values of the probability P= 0.000 0.01.Two sets of data were negatively correlated.3. With the increase of time of modeling,pathological change of muscle were irreversible.CONCLUSION In the rabbit osteofascial compartment syndrome, intracompartment pressure reach the standard of diagnosis of compartment syndrome in 4-6 hours, which were an important stage in the formation ofosteofascial compartment syndrome. The level of osteofascial compartmental pressure and blood oxygen saturation were negatively correlated. The higher osteofascial compartmental pressure were, the lower oxygen saturation became, which can indirectly reflect ischemia and hypoxia.This method were simple, convenient and feasible in the diagnosis of osteofascial compartment syndrome.