Civilian uses of hemoglobin-based oxygen carriers

This article briefly discusses a few key issues related to transfusion, the concept of hemoglobin-based red blood cell substitutes (HBOCs), and some parameters useful in evaluating the current properties of solutions. Potential uses of HBOCs in civilian applications are identified and listed. Use of HBOCs as a hemodiluent for intraoperative autologous blood donation (IAD) is a particular application that has relevance in many surgical settings and this is discussed in some detail. Data from a Phase III clinical trial is presented to show the potential for avoiding the use of allogeneic blood and blood products in a clinical model of large volume red cell use. Extrapolation to a general use model, primarily based in the potential for surgery, will be noted. Some general parametric values of HBOCs are presented. These values are by no means considered optimal for all HBOCs and are subject to exploration, fine tuning, correction, or even rejection.     

Increased risk of preterm birth in singleton pregnancies resulting from in vitro fertilization-embryo transfer or gamete intrafallopian transfer: a meta-analysis

OBJECTIVE: To perform a systematic review of the literature to determine whether singleton pregnancies resulting from IVF-ET/GIFT are at higher risk for preterm birth (<37 weeks). DESIGN: Literature search and systematic review. SETTING: Medical school. INTERVENTION(S): A MEDLINE search (1965-2000) was performed using the terms "premature labor," "infertility," "pregnancy complications," "gonadotropins," "pregnancy outcome," "preterm delivery," and "in vitro fertilization." Criteria for inclusion were English language, original research article, study patients conceived using IVF-ET (with or without intracytoplasmic sperm injection) or GIFT, pregnancy outcome reported compared with a control group (e.g., naturally conceived singletons at their hospital or a national reference), and prematurity clearly defined. Incomplete articles (e.g., abstracts), reports of other studies, and studies that failed to separate multiple from singleton gestations were excluded. MAIN OUTCOME MEASURE(S): Summary of relative risks of preterm birth. RESULT(S): Twenty-seven articles met all inclusion/exclusion criteria and were analyzed by meta-analysis. The random-effects summary relative risk of preterm birth in singleton pregnancies resulting from IVF-ET/GIFT was 1.98 (95% confidence interval, 1.77-2.22). CONCLUSION(S): The risk of preterm birth in singleton pregnancies resulting from IVF-ET/GIFT is twice that of natural conceived pregnancies.     

Oesophageal and gastric pH profiles in patients with gastro-oesophageal reflux disease and Barrett's oesophagus treated with proton pump inhibitors

BACKGROUND: Acid plays a significant role in the development of gastro-oesophageal reflux symptoms and tissue damage. It is generally assumed that acid suppressive therapy with proton pump inhibitors improves or eliminates symptoms of gastro-oesophageal reflux disease by normalizing intra-oesophageal pH. However, the degree of acid suppression induced by proton pump inhibitor therapy in patients with gastro-oesophageal reflux disease and/or Barrett's oesophagus has not been adequately studied. AIM: To assess the efficacy of proton pump inhibitors in normalizing intra-oesophageal and intra-gastric pH in patients with gastro-oesophageal reflux disease with and without Barrett's oesophagus who have been rendered symptom-free by acid-suppressive therapy. METHODS: Patients with gastro-oesophageal reflux disease and Barrett's oesophagus were prospectively evaluated by dual sensor 24-h pH monitoring while receiving proton pump inhibitor therapy for complete control of gastro-oesophageal reflux disease symptoms. Analyses and comparisons of intra-oesophageal and intra-gastric pH profiles on therapy were then made. RESULTS: One hundred and ten patients, 98 men and 12 women, with gastro-oesophageal reflux disease (n = 62) and/or Barrett's oesophagus (n = 48), were studied. All tolerated proton pump inhibitors well and were asymptomatic at the time of the study. Thirty-six (58%) patients with gastro-oesophageal reflux disease and 24 (50%) patients with Barrett's oesophagus (P = 0.4) normalized their intra-oesophageal pH profiles on proton pump inhibitors. Compared with patients with gastro-oesophageal reflux disease, patients with Barrett's oesophagus were more likely to have higher degree of pathologic acid reflux despite proton pump inhibitor therapy (DeMeester score 50.5 +/- 8.2 vs. 31.4 +/- 4.6, P = 0.03) and exhibited less intra-gastric acid suppression (% total pH < 4.0: 53.9 +/- 2.7 vs. 39.9 +/- 2.6, P = 0.0004), particularly supine (% pH < 4.0: 62.1 +/- 3.4 vs. 44.8 +/- 3.4, P = 0.0006). CONCLUSIONS: Gastro-oesophageal reflux disease patients with or without Barrett's oesophagus continue to exhibit pathologic gastro-oesophageal reflux disease and low intra-gastric pH despite proton pump inhibitor therapy that accomplishes complete reflux symptom control. Further, intra-oesophageal and intra-gastric pH control is significantly more difficult to achieve in patients with Barrett's oesophagus. These findings may have significant therapeutic implications.     

Durability testing of a completely implantable electric total artificial heart

In vitro durability testing was conducted on the Penn State/3M electric total artificial heart (ETAH) to determine device durability and to evaluate device failures. A specialized mock circulatory loop was developed for this testing. Customized software continuously acquired data during the test period, and failures were analyzed using FMEA (failure modes and effects analysis) and FMECA (failure modes, effects, and criticality analysis) principles. Redesigns were implemented when appropriate. Reliability growth principles were then applied to calculate the 1 and 2 year reliability. The 1 and 2 year reliability of the Penn State/3M ETAH was shown to be 96.1% and 59.9%, respectively, at 80% confidence.