Core data set. Importance to health services research, outcomes research, and policy research.

Development of consistent health care information has been hampered by the lack of a core data set that contains clinical information. The Uniform Hospital Discharge Set was developed to record individual discharge profiles derived from hospital billing systems. Using that information, some states developed data repositories. Government and health insurers maintain databases of claims paid. The data are not consistent, not readily available, may not contain all encounters, and are financial, not clinical. Wide variance in number of procedures in different geographic regions, variability in mortality rates, and variance in expenditures for particular conditions have been identified from those databases. However, they contain little information to assess the 'best' clinical practices regarding patient outcome. We describe specific limitations of current data sets and how health services research, outcomes research, and policy research, could be improved by a core data set, as well as recommendations about a core data set.

A method for assigning authorship in multiauthored publications.

BACKGROUND AND OBJECTIVES: Determining authorship for publications is often a difficult process, even more so when individuals from several disciplines collaborate with community organizations to conduct projects. Although multidisciplinary and community-academic partnerships provide fertile ground for publication efforts, disputes about authorship and ownership of data may hinder efforts to disseminate information. This article describes a process for dealing with authorship in multi-professional collaborations. It provides an authorship scale, similar to a neonatal Apgar scale, to determine order of authorship in multi-professional projects. Key components or activities in the process of authorship are identified, and points are assigned to each component in proportion to an investigator's level of activity in each component/activity. Scores are summed and can range from 1 to 35 for each author. The order of authorship is then determined by the relative score of each participant.

Predictors of positive CT scans in the trauma patient with minor head injury.

Routine cerebral CT scanning of patients with minor head injuries has been advocated as a screening procedure for hospital admission. The purpose of this study was to determine whether there were characteristics of the trauma patient with a minor head injury. Glasgow Coma Scale (GCS) of 13-15, that would predict a positive cerebral CT scan. An analysis of 200 patients with potential head injuries transported to our regional trauma center was performed. The following characteristics were analyzed as possible predictors: scene GCS (SC-GCS), emergency room GCS (ER-GCS), a change in GCS from scene to emergency room, loss of consciousness (LOC), and focal neurological deficit. Forty-eight per cent (96/200) of the patients underwent CT scanning of the head. CT scans were positive in 4 per cent (8/200) of the total group and 8.3 per cent (8/96) of those who underwent CT scanning. In the patients without LOC and ER-GCS of 13-15, all CT scans were negative (95% confidence interval 0.0% to 3.4%). In the 93 patients with LOC, eight patients had a positive scan (P < 0.001). Of the nine patients who sustained a skull fracture, five had a positive CT (55.6%; 95% confidence interval 21.2% to 86.3%) (P < 0.0001). Of all the patients with positive CT scans, two underwent emergent craniotomy: one for a depressed skull fracture with underlying contusion, the other for a temporal bone fracture and an epidural hematoma. Both patients had LOC and SC-GCS and ER-GCS of 15.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute toxicity, distribution, and metabolism of 2,4,6-trinitrophenol (picric acid) in Fischer 344 rats.

Picric acid (2,4,6-trinitrophenol) is widely used in industry, by the military, and as a research/clinical chemistry reagent. Characterization of the toxicity of this chemical has been limited. Thus the acute toxicity, distribution, and metabolism of picric acid were investigated using Fischer 344 rats. The LD50 for picric acid following oral dosing of male and female rats was established as 290 and 200 mg/kg, respectively. Blood gas analysis indicated severe acidosis during acute intoxication. Metabolism of picric acid was limited to reduction of nitro groups to amines. Metabolites isolated from urine included N-acetylisopicramic acid (14.8%), picramic acid (18.5%), N-acetylpicramic acid (4.7%), and unidentified components (2.4%). Approximately 60% of the parent picric acid was excreted unchanged. The plasma half-life for picric acid was 13.4 h with a gut absorption coefficient (ka) of 0.069 h-1. Twenty-four hours following oral administration of [14C]picric acid (100 mg/kg), the primary depots of radioactivity (per gram tissue basis) were blood, spleen, kidney, liver, lung, and testes. Respective tissue/blood ratios were 0.37, 0.31, 0.28, 0.26, and 0.22. All other tissue assayed had partition ratios < 0.20, with brain and adipose tissue having the least amount of radioactivity. Tissue/blood ratios were essentially maintained over a 48-h postadministration period. Binding (in vitro) of [14C]picric acid to plasma proteins (whole blood preparations) demonstrated both high- and low-affinity binding sites, with dissociation constants of 3.18 x 10(-6) and 2.85 x 10(-4) M, respectively. The findings of this investigation provide information on the acute toxicity, metabolism, and distribution of picric acid, which can be used in risk assessment analyses and in the design of subchronic and chronic toxicity tests.

A subchronic dermal exposure study of diethylene glycol monomethyl ether and ethylene glycol monomethyl ether in the male guinea pig.

Diethylene glycol monomethyl ether (DEGME) has been selected as a replacement anti-icing additive for ethylene glycol monomethyl ether (EGME) in Navy jet aircraft fuel. This experiment was performed to determine whether DEGME produced similar toxicity to EGME following dermal exposure. Male guinea pigs were dermally exposed to 1.00, 0.20, 0.04, or 0 (control) g/kg/day DEGME for 13 weeks, 5 days/week, 6 hr/day. Another group of animals was similarly exposed to 1.00 g/kg/day EGME. Body weights as well as testicular and splenic weights were reduced as a result of exposure to EGME, DEGME-exposed animals exhibited decreased splenic weight in the high- and medium-dose (1.00 and 0.20 g/kg/day) exposure groups only. Hematologic changes in EGME-exposed animals included mild anemia with increased erythrocytic mean corpuscular volumes and a lymphopenia with increased neutrophils. Similar hematological changes were not observed in any animals exposed to DEGME. Serum creatine kinase activity was increased in animals exposed to EGME, and serum lactate dehydrogenase activity was increased in EGME and 1.00 g/kg/day DEGME-exposed animals. In general, DEGME produced minimal toxicological changes following dermal exposure, whereas the toxicological changes observed following similar exposure to EGME were much more profound.

Interspecies variability in propylene glycol dinitrate-induced methemoglobin formation.

Interspecies variability of propylene glycol dinitrate (PGDN)-induced methemoglobin formation was studied in vitro employing erythrocytes from four separate species. The net rate of methemoglobin formation was significantly different among species with dog greater than guinea pig greater than rat greater than or equal to human. This order of susceptibility was maintained in stroma-free hemolysates, indicating that interspecies variability was not a reflection of differences in red cell membrane permeability or intracellular transport of PGDN. The erythrocytic enzymes, catalase, superoxide dismutase, glutathione peroxidase, 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, methemoglobin reductase, and glutathione-S-transferase, were assayed by adaptation of existing methods to a centrifugal analyzer. The above enzymes were removed from hemoglobin derived from each species and the order of susceptibility to PGDN-induced methemoglobin formation remained essentially the same with dog greater than guinea pig greater than human = rat. However, the net rate of PGDN-mediated oxidation of hemoglobin to methemoglobin increased in purified hemoglobin preparations from each species. These results demonstrate that there is species variability in the net rate of PGDN-mediated methemoglobin formation. Total enzyme activity in erythrocytes may contribute to reduction in the net rate of methemoglobin formation. However, the primary determinant of the net rate of methemoglobin formation induced by PGDN appears to be the structure of each hemoglobin molecule.

Potentiation of 2,5-hexanedione neurotoxicity by methyl ethyl ketone.

Chronic oral administration of a combination of 2.2 mmol methyl ethyl ketone (MEK) and 2.2 mmol 2,5-hexanedione (2,5-HD)/kg/day, 5 days/week resulted in more rapid onset of motor deficits than did chronic dosing with 2.2 mmol 2,5-HD/kg/day alone. In kinetic studies blood time courses of 2,5-HD were determined in rats in the presence and absence of MEK. Concomitant administration of MEK reduced blood 2,5-HD clearance and increased the area under the curve (AUC) for the blood 2,5-HD. In companion experiments with 2,5-[1,6-14C]HD as a tracer, neural and nonneural tissues were examined 72 hr following the last treatment at Weeks 1, 2, and 3 of chronic administration of 2,5-HD alone or in combination with an equimolar dose of MEK. Rats treated with 2,5-[14C]HD alone or in combination with MEK demonstrated no difference in total or trichloroacetic acid-precipitable radioactivity in blood, in liver homogenates, or in neurofilament-enriched fractions from sciatic nerve and spinal cord. The data support a suggestion that the potentiation of hexacarbon neurotoxicity by MEK is the result of the persistence of the neurotoxic metabolite in the blood and not the enhanced metabolism of parent hexacarbon to 2,5-HD.

Gentamicin-induced hypomagnesemia.

There have been several case reports of hypomagnesemia associated with gentamicin therapy. A cause and effect relationship between gentamicin and hypomagnesemia has been difficult to establish in these cases due to: 1) large doses of gentamicin; 2) concomitant administration of other antibiotics and cytotoxic agents; 3) failure to monitor drug levels; and 4) poor oral intake. To test for a direct cause and effect relationship and to determine the frequency of gentamicin-induced hypomagnesemia, we administered the drug for 10 days to six healthy, well-fed, subhuman primates. Five of the six animals developed a mean decrease in serum magnesium of 0.34 mg/dl (P = 0.03) after 10 days of therapy. Four of the five had levels in the frankly hypomagnesemic range (less than 1.4 mg/dl). Urine magnesium values were inappropriately elevated in relation to serum magnesium concentrations. It is concluded that gentamicin-induced hypomagnesemia may occur more commonly than has been previously appreciated. Serial monitoring of serum magnesium in patients receiving gentamicin is recommended.

Bedside blood glucose determinations in critical care medicine: a comparative analysis of two techniques.

The accuracy of a new reagent test strip (Chemstrip BG) for the quantitative estimation of whole blood glucose concentration was compared to that of a widely used test strip (Dextrostix). To perform the comparative study, venous blood specimens were obtained from 133 patients. Interpretations of reagent strip glucose readings were made by three observers who separately recorded their impressions from the two strips on each patient. These estimated levels were compared to quantitative (glucose oxidase) concentrations measured from the same specimen. Although there were significant correlations (p less than 0.001) between both reagent strips and the measured values, the Chemstrip BG results more closely approximately measured values for the range of glucose concentrations encountered (10-600 mg/dl). In addition, Chemstrip BG was easier to read and measured a wider range of values than Dextrostix and, unlike Dextrostix, Chemstrip BG strips could be stored for review at a later time. This new glucose test strip accurately and rapidly determines whole blood glucose concentration at the bedside.

The influence of asphyxia on fetal lidocaine toxicity.

Local anesthetics have played an important role in modern obstetrics. Although reasonably safe, these agents have been shown to have detrimental effects in some fetuses. In the present study we examined the influence of acute asphyxia in the fetal lamb on the distribution and cerebral uptake of maternally infused lidocaine. Results demonstrate that asphyxia is associated with higher lidocaine concentrations in the fetal plasma, increased presentation of the drug to the fetal brain, and increased cerebral lidocaine uptake. These findings underscore the importance of evaluation of fetal status when considering the risks and benefits of maternal drug use.

Sickle cell trait and glucose-6-phosphate dehydrogenase deficiency. Effects on health and military performance in black Navy enlistees.

The purpose of this longitudinal study was to compare the Navy performance and health status during a four-year enlistment of four subsamples of black enlistees who began active service between Feb 14 through Sept 15, 1972. On the basis of results obtained from screening procedures for hemoglobinopathies, a sample of 8,725 enlistees was separated into four subgroups: 599 subjects with sickle cell trait, 1,003 subjects with glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, 73 subjects with both trait anomalies, and 7,050 normal subjects. Results of comparative analyses indicated that the three trait subsamples did not differ significantly from the normal group on demographic and service-related variables, seven performance criteria, hospitalization rates, or mortality. Thus, the trait anomalies studied were found to be benign under routine conditions of naval service.

Measurement of Erythrocyte 2,3-diphosphoglycerate with a centrifugal analyzer.

Intra-erythrocytic concentration of 2,3-diphosphoglycerate is a major determinant of the oxygen affinity of hemoglobin. We report here the adaptation of its assay to a centrifugal analyzer, with use of a commercially available reagent. Results are calculated by using the reagent-blank-corrected absorbance change at 340 nm between 120 and 300 s for the samples and a 2.5 mmol/L standard. Under these conditions the standard curve is linear to 5 mmol/L. The compound in a 101-fold aqueous hemolysate is stable for several weeks at either -4 or -70 degrees C. Assay sensitivity and precision are excellent and results agree well with those by the corresponding manual method.

Cardiovascular and metabolic manifestations of heat stroke and severe heat exhaustion.

We prospectively studied the clinical, biochemical (including creatine phosphokinase (CPK) isoenzymes) and electrocardiographic features of exertional heat stroke in 13 patients (group 1) and severe heat exhaustion in 14 patients (group 2). Despite initial presentations with severe hyperthermia, tachycardia and hypotension, only one patient with heat stroke had myocardial ischemia. The CPK isoenzymes were not indicative of myocardial damage in any patient. The patients with heat stroke were somewhat more dehydrated than those with heat exhaustion as measured by differences in serum creatinine, sodium and osmolality, and the former (group 1) had a significantly lower initial glucose level (P less than 0.05). Although significant differences in potassium were not observed in the pretreatment samples, at 12 hours the serum potassium was significantly lower in group 1 (P less than 0.05). This suggests that this group may have been more potassium-depleted at the time of heat stroke. Prompt recognition and vigorous therapy were successful in rapidly lowering high temperatures and in preventing serious complications.

Hemorrhagic shock treatment with hot intravenous fluid in dogs.

In hot climates, only high temperature fluids (are greater than 100 F) may be available for treatment of blood loss shock in combat casualties. Can the hot fluid be used safely and effectively? We compared hot Ringer's lactate (51.7% C/125 F) resuscitation (n=10) to body-temperature (100 F) fluid resuscitation (n=10) in a hemorrhagic shock dog model. One liter of 125 F fluid, as part of the resuscitation, did not cause hyperthermia, red blood cell hemolysis, or any significantly different response in the cardiovascular system when compared to body-temperature fluid. All animals in both groups survived. These findings suggest that battlefield use of hot fluids in controlled amounts can be safe and effective for treatment of blood loss shock in human combat casualties.

Partial characterization of a beta-lactamase from Vibrio parahaemolyticus by a new automated microiodometric technique.

A number of characteristics were determined with a new automated method for a partially purified beta-lactamase from Vibrio parahaemolyticus. The enzyme had a molecular weight of 28,000 by gel filtration, a pH optimum between 6.5 and 7.0, and a temperature optimum at 36 degrees C. With penicillin G as the substrate, the K(m) value for the beta-lactamase was 54.4 muM. The beta-lactamase was inhibited by cloxacillin but not by p-chloromercuribenzoate. The enzyme was similar but not identical to beta-lactamases from gram-negative, "nonhalophilic" organisms described by other workers. The microiodometric assay to measure beta-lactamase activity was automated with the use of a centrifugal analyzer that permitted 14 simultaneous determinations. Within-run precision was tested by putting the same reaction mixture in each well, and the coefficient of variation was only about 3%. Four extracts from different strains of halophilic vibrios were used to demonstrate that reaction rates were linear with enzyme concentration. The correlation coefficient of activity by the automated method with activity by the spectrophotometric method was 0.9721, demonstrating that the methods compared favorably with each other. The automated method greatly facilitated the characterization of the beta-lactamase.

Dyspnea in divers at 49.5 ATA: mechanical, not chemical in origin.

Pulmonary function was studied in six divers living in a hyperbaric chamber at a pressure nearly fifty times normal (49.5 atmospheres absolute (ATA), equivalent to 488 m or 1600 ft seawater (fsw)). As expected, ventilatory function was reduced. At 49.5 ATA, maximum voluntary ventilation (MVV) was 45% less than the control value. Instantaneous rates of gas flow during forced expiration were similarly reduced, especially those flow rates measured high in the lung volume. These reductions occurred despite an apparent increase in functional residual capacity (FRC) and the use of transpulmonary pressures considerably greater than those exerted during the same maneuvers at normal (sea-level) pressure. During underwater work at 49.5 ATA, the divers rapidly became exhausted at moderate levels of oxygen consumption (1.9 liters/min), showing severe dyspnea and impending syncope. These symptoms were not due to retention of carbon dioxide, nor to hemodynamic or metabolic causes. Thus, dense gas breathing, like asthma, exemplifies a state in which severe dyspnea may occur with normal or low arterial carbon dioxide and normal oxygen transport. The physiological adjustments the divers employed were similar to those seen in acute asthma, imposing an elastic load in addition to the flow-resistive work of breathing a gas mixture eight times as dense as air. Although men can do moderate work under conditions similar to those of this experiment, they will have only a limited physiological reserve available to meet the possibilities of emergencies or respiratory infections.

Medical aspects of sickle hemoglobin in military personnel.

The Department of Defense (DOD) will soon issue a directive to test all incoming military personnel for the presence of hemoglobin S. The military testing program for hemoglobin S is an occupational medicine program. This report includes a discussion of armed services physical standards, a description of the Navy effort to evaluate an automated system for detection of hemoglobin S, and the proposed DOD directive.