Soller Babs R, Hagan R Donald, Shear Michael, Walz J Matthias, Landry Michelle, Anunciacion Dulce, Orquiola Alan, Heard Stephen O
Department of Anesthesiology, University of Massachusetts Medical School, Worcester, MA, USA.
Physiol Meas. 2007 Jun;28(6):639-49. doi: 10.1088/0967-3334/28/6/003. Epub 2007 May 3.
Oxygen and acid-base status during exercise is well established for the lungs, large arteries and veins. However, values for these parameters in exercising muscle are less frequently reported. In this study we examined the relationship between intramuscular PO(2), pH, PCO(2) and the comparable venous values during rhythmic isometric handgrip exercise at target levels of 15%, 30% and 45% of maximum voluntary contraction (MVC). A small fiber optic sensor was inserted into the flexor digitorum profundus (FDP) muscle for continuous measurement of intramuscular (IM) PO(2), pH and PCO(2). Venous blood samples were taken from the forearm every minute during each exercise bout. IM pH and PCO(2) were similar to their venous counterparts at baseline, but the difference between IM and venous values increased when exercise exceeded 30% MVC. During exercise at 15% MVC and greater, venous PO(2) declined from 40 to 21 Torr (approximately 5.3 to 2.8 kPa). IM PO(2) declined from 24 to 8 Torr with 15% MVC, and approached 0 Torr at 30% MVC and 45% MVC. IM pH declined rapidly when IM PO(2) reached 10 Torr and continued to decrease with increasing exertion, despite an IM PO(2) near 0 Torr.
运动期间肺部、大动脉和静脉的氧气及酸碱状态已得到充分研究。然而，关于运动肌肉中这些参数的值的报道较少。在本研究中，我们在最大自主收缩（MVC）的15%、30%和45%的目标水平下进行有节奏的等长握力运动时，研究了肌肉内PO₂、pH、PCO₂与相应静脉值之间的关系。将一个小型光纤传感器插入指深屈肌（FDP）肌肉中，以连续测量肌肉内（IM）PO₂、pH和PCO₂。在每次运动期间，每分钟从前臂采集静脉血样本。静息时，IM pH和PCO₂与其静脉对应值相似，但当运动超过30%MVC时，IM和静脉值之间的差异增大。在15%MVC及以上强度运动时，静脉PO₂从40 Torr降至21 Torr（约5.3至2.8 kPa）。15%MVC时，IM PO₂从24 Torr降至8 Torr，在30%MVC和45%MVC时接近0 Torr。当IM PO₂达到10 Torr时，IM pH迅速下降，尽管IM PO₂接近0 Torr，但随着运动强度增加仍继续下降。
