Society of University Surgeons

Our recent experimental study showed that peripheral muscle tissue oxygen saturation (StO2), determined noninvasively by near-infrared spectroscopy (NIRS), was more reliable than systemic hemodynamics or invasive oxygenation variables as an index of traumatic shock. The purpose of this study was to establish the normal range of thenar muscle StO2 in humans and the relationship between shock state and StO2 in trauma patients. This was a prospective, nonrandomized, observational, descriptive study in normal human volunteers (n = 707) and patients admitted to the resuscitation area of our Level I trauma center (n = 150). To establish a normal StO2 range, an NIRS probe was applied to the thenar eminence of volunteers (normals). Subsequently, in a group of trauma patients, an NIRS probe was applied to the thenar eminence and data were collected and stored for offline analysis. StO2 monitoring was performed continuously and noninvasively, and values were recorded at 2-minute intervals. Five moribund trauma patients were excluded. Members of our trauma faculty, blinded to StO2 values, classified each patient into one of four groups (no shock, mild shock, moderate shock, and severe shock) using conventional physiologic parameters. Mean +/- SD thenar StO2 values for each group were as follows: normals, 87 +/- 6% (n = 707); no shock, 83 +/- 10% (n = 85); mild shock, 83 +/- 10% (n = 19); moderate shock, 80 +/- 12% (n = 14); and severe shock, 45 +/- 26% (n = 14). The thenar StO2 values clearly discriminated the normals or no shock patients and the patients with severe shock (p < 0.05). Decreased thenar muscle tissue oxygen saturation reflects the presence of severe hypoperfusion and near-infrared spectroscopy may be a novel method for rapidly and noninvasively assessing changes in tissue dysoxia.

Beck1,23 and O'Shaughnessy4,5, 6 have demonstrated that an effective collateral blood supply to the heart can be established by the use of pedicled muscle and omental grafts. Others7,89 have similarly employed the omentum to augment the circulation to the kidneys. The present experiments10 were performed to determine whether an accessory arterial blood supply from an extracranial source could be provided for the brain by applying to its cortical surface a pedicled graft of temporal or suboccipital muscles.Monkeys (Macaca mulatta) weighing 2 to 3 kilos were used as experimental animals. The operative approach and technic, as well as the sequence of the procedures, varied slightly during the course of the experiments, but the main objectives in each instance remained the same. After either preliminary or concomitant ligation of one or more of the main arteries to the brain, the superior border of the temporal muscle was separated from its origin and reflected to expose most of the underlying squamous portio...