Determination of oxygen dosage effects on cytochrome oxidase after anoxia in brain.

Recent evidence reports that high doses of O(2) administered via hyperbaric oxygen therapy (HBOT) improve the return of spontaneous circulation (ROSC), and the outcome of damage to the heart following a 25 min normothermic cardiac arrest. However, excessive O(2) during HBOT can be toxic. Near infrared absorbance spectroscopy (NIRS) measures and determines when cytochrome oxidase (aa(3)), the O(2) end user, changes from reduced to oxidized, signifying adequate dosage. Present NIRS monitoring methods do not account for change in scattering expected in severe anoxia. Given this limitation, we simultaneously measured changes in intensity and scattering that occurred over time after 830 nm light traveled 4.25 cm through brain tissue during both normoxia and anoxia. Results indicated increased intensity and scattering during anoxia with correlation between the two, demonstrating that scattering does not remain constant and is associated with intensity. With this additional insight in concurrent scattering and intensity change during anoxia, we believe improvements can be made to our aa(3) measuring technique resulting in a method to ascertain adequate O(2) dosage during HBOT.

Heterotopic interstitial pregnancy: A case report.

INTRODUCTION: Before the advent of assisted reproductive technologies, the incidence of heterotopic pregnancy was estimated to be in 1 out of 30,000 pregnancies in the United States. With interstitial pregnancy comprising only 2.4% of ectopic pregnancies, spontaneous heterotopic interstitial pregnancies are exceedingly rare. CASE: A 27-year-old pregnant woman (gravida 3 para 1011) with a history of one prior term vaginal delivery and a spontaneous abortion in the first trimester presented to the emergency department with abdominal pain and a positive home pregnancy test. Transvaginal ultrasound confirmed heterotopic pregnancy and she underwent operative management, at which point a ruptured interstitial pregnancy was identified. CONCLUSION: Heterotopic and interstitial pregnancies are rare and to see them together in a spontaneous pregnancy is virtually unique. The case report describes our management of this rarely seen condition.