Search

UNLABELLED Clinical diagnosis of cyanide poisoning is complicated by the lack of an easy, convenient assay for cyanide concentration in blood. Therapy may be delayed with unconfirmed diagnosis because the conventional antidote to cyanide poisoning exposes patients to substantial risks. We developed a new spectrophotometric assay to measure cyanide by extraction into a sodium hydroxide trap, followed by the addition of exogenous methemoglobin as a colormetric indicator. Samples of blood from 15 healthy subjects and 5 patients who had received prolonged nitroprusside infusions were assayed. To optimize assay characteristics, methemoglobin concentrations, pH, temperature, incubation time, and buffer strengths were varied. Duplicate samples were assayed by using the polarographic method for assay validation. Over a range from 300 ng/mL to 7 microg/mL, the correlation between methods was r = 0.983. Interassay and intraassay variability were 5% and 2%, respectively. Samples drawn from the five patients and tested by using both methods yielded a correlation of r = 0.978. This new assay for cyanide in blood may greatly facilitate the diagnosis and treatment of cyanide ingestion. The use of methemoglobin as the colorimetric indicator in the assay contributes to its low cost and ease of use. IMPLICATIONS Cyanide, an important factor in death from burn-related inhalation injury, is difficult and time-consuming to measure. We developed a new, rapid blood test for cyanide using methemoglobin as a colormetric indicator. A rapid, accessible test for cyanide may speed the diagnosis and treatment of cyanide poisoning.

An attending physician in an urban teaching hospital faces an ethical dilemma when a mother refused to allow an African American medical student to examine her child. Virtual Mentor is a monthly bioethics journal published by the American Medical Association.

Pain from vaso-occlusive crisis (VOC) is the major cause of hospitalization in patients with sickle cell disease (SCD). The beneficial therapeutic effects of inhaled nitric oxide (NO) on the pathophysiology of SCD have been reported. A double-blind, randomized, placebo-controlled clinical trial was conducted to determine whether NO breathing reduces acute VOC pain in adult patients and to study the safety of inhaled NO. Twenty-three patients experiencing acute VOC were enrolled. After randomization but before treatment, five were found to not meet final eligibility criteria. Nine patients were assigned to inhaled NO (80 ppm) and nine to placebo (21% O2). Primary outcome was the mean change in pain scores after 4 hr of inhalation, measured on a 10-cm visual analog scale (VAS). Both groups had similar baseline VAS pain scores but inhaled NO significantly reduced pain scores compared with placebo (P 5 0.02) at the end of NO inhalation. Secondary outcome was parenteral morphine use at baseline, 4, and 6 hr. Parenteral morphine use was lower in the inhaled NO group, but the difference was not statistically significant.Safety assessments included systolic blood pressure measurements,pulse oximetry readings, concentration of delivered nitrogen dioxide, and concentration of methemoglobin (metHb). None of these NO toxicities was observed.

Summary Background : The purpose of this study was to evaluate, in the pediatric ambulatory surgical population, the efficacy of: (i) oral transmucosal fentanyl citrate (OTFC), when given preoperatively, to reduce postoperative excitement associated with sevoflurane, and (ii) intravenous ondansetron to reduce postoperative nausea and vomiting (PONV) associated with OTFC. Methods : This randomized, double-blinded, placebo controlled study evaluated the efficacy of OTFC [normal dose (ND) = 10–15 μg·kg−1 or low dose = 100 μg] compared with placebo in the prevention of postoperative agitation; and the efficacy of ondansetron (0.1 mg·kg−1 to 4 mg) compared with placebo to reduce PONV associated with OTFC. Results : There were 125 patients evaluated (2–10 years old, ASA class I or II and weight 10–40 kg). Preoperatively OTFC was associated with an increased likelihood of cooperation at baseline (P = 0.018). Postoperatively there was a higher incidence of vomiting in children that received OTFC. The anxiety/agitation of patients entering the PACU was significantly less in children who received OTFC ND (P

A physician discusses potential factors underlying disparities in health care and health outcomes and advocates for standards to improve cultural competence, improve health literacy, and reduce disparities. Virtual Mentor is a monthly bioethics journal published by the American Medical Association.

The structure of HbS fibers has been analyzed from electron micrographs of negatively stained particles using three-dimensional reconstruction techniques. Fibers are composed of the same structural unit as crystals, namely the Wishner-Love double strand, but the arrangement of the double strands in fibers and crystals is quite different. This raises questions regarding the manner in which such structures might fuse to form crystals. The crystallization must be accompanied by a considerable rearrangement of the double strands and the fibers, which have net polarity, must combine in such a way as to form a non-polar crystal. It is of interest in this regard to consider whether the structure of fibers associated into ordered bundles, or fascicles, differs from the structure of individual fibers. The structure and interaction of fibers within large arrays may have clinical significance as it is the formation of bundles of fibers within the red blood cell which leads to the clinical manifestations of sickle cell disease.

In vivo, deoxyhemoglobin S fibers associate into bundles, or fascicles. It is the formation of these bundles within red blood cells which leads to the clinical manifestations of sickle cell disease. A similar phenomenon is observed in vitro. Fascicles are initially small and poorly ordered but, with time, become progressively larger, more tightly packed and more highly ordered. The most tightly packed fascicles display crystalline order and form “crystals of fibers”. We have constructed computer generated models of longitudinal projections of crystalline fascicles of sickle hemoglobin (HbS) fibers. A comparison of the models with electron micrographs provides a means of accurately determining the three dimensional packing arrangement of fibers and the nature of the fiber-fiber interactions within fascicles.Electron micrographs of longitudinal sections of well ordered fascicles reveal a number of characteristic views, one of which is shown in figure 2a. The different views observed in the micrographs arise because of differing orientations of fascicle sections relative to the angle of projection. This was demonstrated by experiments in which the specimen was tilted about its long axis. Different views could be interconverted by varying the angle of tilt.

An ideal permanent gastrostomy should allow for simple administration of food and also should prevent the reflux of food or the leakage of acid gastric chyme onto the anterior abdominal wall. Having become discouraged with many of the usual gastrostomy methods, particularly as related to the reflux of acid gastric chyme (Fig. 1), we sought a new method which would have the advantages of an ideal gastrostomy. Merendino and Dillard (1955) used an isolated loop of jejunum as a substitute sphincter between esophagus and stomach. One of the outstanding features of this operation has been the prevention of gastroesophageal reflux due, apparently, to the peristaltic action of the jejunal loop. It seemed to us that such a loop had a potential quality that would be useful in the construction of a permanent gastrostomy. On the basis of these considerations, a technique evolved using an isolated loop of jejunum between the