STUDY OBJECTIVE: To determine the effect of intravenous administration of prostaglandin E1 (PGE1) in inducing controlled hypotension during general anesthesia. DESIGN: Randomized, prospective study. SETTING: Inpatient surgery at a university hospital. PATIENTS: 57 ASA physical status I and II patients scheduled for total hip replacement. INTERVENTIONS: In 29 patients undergoing total hip replacement, PGE1 (0.11 +/- 0.03 micrograms/kg/min) was infused to induce hypotension during general anesthesia with enflurane, isoflurane, or sevoflurane in nitrous oxide and oxygen. In another 28 patients, the control group, normotensive anesthesia was performed for the same procedure. MEASUREMENTS AND MAIN RESULTS: Systolic blood pressure decreased significantly (p < 0.01) from 136 +/- 22 mmHg to 93 +/- 10 mmHg during PGE1 infusion, although heart rate did not change significantly. Arterial hemoglobin oxygen saturation showed a mild but significant decrease (p < 0.05) during PGE1 infusion. Blood loss (480 +/- 132 ml) and blood transfusion (280 +/- 260 ml) during surgery were significantly less in patients with hypotensive anesthesia (p < 0.01 and p < 0.05, respectively) than in patients with normotensive anesthesia (667 +/- 326 ml and 468 +/- 395 ml, respectively). Blood loss and blood transfusion after surgery were similar in both groups. In the recovery room or surgical ward, 3 of 29 patients with hypotensive anesthesia needed rapid blood transfusion because of moderate hypotension. The volume of urine during surgery was significantly less (p < 0.05) in the control group. Two patients developed mild phlebitis at the site of the PGE1 infusion, but there were no serious side effects. CONCLUSION: These data suggest that PGE1 can be used safely to induce hypotension, thereby reducing blood loss during total hip replacement with general anesthesia.

Alprostadil↗

PubMedDate not supplied

Experimental stationary potential recorded with using spine and skull model.

This study aims at investigating experimentally the structural effects of various shapes of volume conductors, which are surrounded by an insulated skull and spinal canal model, on nerve action potentials (NAP). NAP were recorded through volume conductors inside and outside a model. We noted stationary potentials emerged at where the volume conductor made structural transitions. These results were analyzed using the field diagram of isopotential curves. The diagrams of the electrical field demonstrated that the stationary potentials arise owing to abrupt disequilibrium of the electrical field brought about by the change of the volume conductor surrounded by the insulated model.

Action Potentials↗

PubMedDate not supplied

Experimental study of measurement of regional bone blood flow in the adult mongrel dog using radioactive microspheres.

To date, no one has conclusively accurately measured the regional bone blood flow mainly due to the lack of a proper investigative method. In this study, regional blood flow in the femur and tibia in adult mongrel dogs were studied using 85Sr-and 141Ce-labeled microspheres with a diameter of 15 +/- 5 microns. The blood flow rates were calculated by relating the radioactivity from tissue samples that from sample blood with a known flow. The highest rate of blood flow, 48.7 ml/min/100 g, was found in the femoral marrow and the lowest, 3.0 ml/min/100 g, in the diaphyseal cortex of the tibia. Flow rates in the metaphyseal regions, about 15 or 20 ml/min/100 g, were one and a half or 2 times greater than those in the epiphyseal regions. These values were mostly within the range of values reported by other investigators. Radioactive microspheres can be applied not only to physiological conditions but also to various pathological conditions if their size and the dose, the site and method of injection and tissue sampling are investigated further.

Animals↗