Significance of kinetics for sorption on inorganic colloids: modeling and experiment interpretation issues

A two-site kinetic model for solute sorption on inorganic colloids is developed. The model quantifies linear first-order sorption on two types of sites ("fast" and "slow") characterized by two pairs of rates (forward and reverse). We use the model to explore data requirements for long-term predictive calculations of colloid-facilitated transport and to evaluate laboratory kinetic sorption data of Lu et al.. Five batch sorption data sets are considered with plutonium as the tracer and montmorillonite, hematite, silica, and smectite as colloids. Using asymptotic results applicable on the time scale of limited duration experiments, a robust estimation procedure is developed for the fast-site partitioning coefficient K(C) and the slow forward rate alpha. The estimated range of K(C) is 1.1-76 L/g, and the range for alpha is 0.0017-0.02 1/h. The fast reverse rate k(r) is estimated in the range 0.012-0.1 1/h. Comparison of one-site and two-site sorption interpretations reveals the difficulty in discriminating between the two models for montmorillonite and to a lesser extent for hematite. For silica and smectite, the two-site model clearly provides a better representation of the data as compared with a single site model. Kinetic data for silica are available for different colloid concentrations (0.2 g/L and 1 g/L). For the range of experimental conditions considered, alpha appears to be independent of colloid concentration.

Viewpoint: a comparison of cause-of-injury coding in U.S. military and civilian hospitals

INTRODUCTION

Complete and accurate coding of injury causes is essential to the understanding of injury etiology and to the development and evaluation of injury-prevention strategies. While civilian hospitals use ICD-9-CM external cause-of-injury codes, military hospitals use codes derived from the NATO Standardization Agreement (STANAG) 2050.

DISCUSSION

The STANAG uses two separate variables to code injury cause. The Trauma code uses a single digit with 10 possible values to identify the general class of injury as battle injury, intentionally inflicted nonbattle injury, or unintentional injury. The Injury code is used to identify cause or activity at the time of the injury. For a subset of the Injury codes, the last digit is modified to indicate place of occurrence. This simple system contains fewer than 300 basic codes, including many that are specific to battle- and sports-related injuries not coded well by either the ICD-9-CM or the draft ICD-10-CM. However, while falls, poisonings, and injuries due to machinery and tools are common causes of injury hospitalizations in the military, few STANAG codes correspond to these events. Intentional injuries in general and sexual assaults in particular are also not well represented in the STANAG. Because the STANAG does not map directly to the ICD-9-CM system, quantitative comparisons between military and civilian data are difficult.

CONCLUSIONS

The ICD-10-CM, which will be implemented in the United States sometime after 2001, expands considerably on its predecessor, ICD-9-CM, and provides more specificity and detail than the STANAG. With slight modification, it might become a suitable replacement for the STANAG.

Data elements for emergency department systems, release 1.0 (DEEDS): a summary report. DEEDS Writing Committee

Variations in the way that data are entered in emergency department record systems impede the use of ED records for direct patient care and deter their reuse for many other legitimate purposes. To foster more uniform ED data, the Centers for Disease Control and Prevention's National Center for Injury Prevention and Control is coordinating a public-private partnership that has developed recommended specifications for many observations, actions, instructions, conclusions, and identifiers that are entered in ED records. The partnership's initial product, Data Elements for Emergency Department Systems, Release 1.0 (DEEDS), is intended for use by individuals and organizations responsible for ED record systems. If the recommended specifications are widely adopted, then problems--such as data incompatibility and high costs of collecting, linking, and using data--can be substantially reduced. The collaborative effort that led to DEEDS, Release 1.0 sets a precedent for future review and revision of the initial recommendations.

Data elements for emergency department systems, release 1.0 (DEEDS): a summary report. DEEDS Writing Committee

Variations in the way that data are entered in ED record systems impede the use of ED records for direct patient care and deter their reuse for many other legitimate purposes. To foster more uniform ED data, the Centers for Disease Control and Prevention's (CDC) National Center for Injury Prevention and Control is coordinating a public-private partnership that has developed recommended specifications for many observations, actions, instructions, conclusions, and identifiers that are entered in ED records. The partnership's initial product. Data Elements for Emergency Department Systems, Release 1.0 (DEEDS), is intended for use by individuals and organizations responsible for ED record systems. If the recommended specifications are widely adopted, then problems--such as data incompatibility and high costs of collecting, linking, and using data--can be substantially reduced. The collaborative effort that led to DEEDS, Release 1.0 sets a precedent for future review and revision of the initial recommendations.

Comparative evaluation of selective and nonselective culture techniques for isolation of group A beta-hemolytic streptococci

A new selective blood agar medium, Strep A Isolation Agar (SI) from Remel (Lenexa, KS), was compared with Becton Dickinson's Streptococcus Selective Agar (SA) (Becton Dickinson Microbiology Systems, Cockeysville, MD) and with a nonselective Columbia Blood Agar (CB) (Difco, Detroit, MI). Throat swabs from patients with acute pharyngitis were cultured with the use of a single swab to inoculate each of the three plates in a specific order, rotating in three-week cycles. Plates were examined (each medium by a different technologist) after 24 and 48 hours of incubation at 35 degrees C in 5% carbon dioxide, and beta-hemolytic streptococci were serogrouped with the use of coagglutination. The positivity rate was significantly greater for SI (25%) and SA (26%) than for CB (18%) (P less than 0.001). The respective rates of Group A streptococcal detection by SI, SA, and CB were 91%, 95%, and 67%, respectively. However, a feature associated with the use of SI or SA, in contrast to CB, was delayed identification of isolates by 24-48 hours because of small colony size, slower growth rate, and inability to serogroup colonies taken directly from primary culture plates. Recovery of non-Group A beta-hemolytic streptococci occurred with CB (12%) greater than SI (8%) greater than SA (6%). SI is superior to a nonselective medium, such as CB, and is equal to SA for recovery of Group A streptococci from throat cultures.

Emergency defibrillation using a temporary pacing electrode catheter

Direct application of electrical current to the heart utilizing special equipment such as implantable defibrillators or specially designed catheters has been useful in patients with recurrent ventricular tachyarrhythmias. We describe a patient who developed intractable ventricular fibrillation (VF) during the course of electrophysiologic testing. VF continued for 50 minutes, during which time multiple transthoracic shocks of 360 joules failed to convert the arrhythmia. Intracardiac shocks were then delivered via a transvenous 6 French standard quadripolar pacing catheter positioned in the right ventricular apex by direct application of the defibrillator paddle to the catheter, with the patient lying on the posterior paddle. Energy of up to 300 joules failed to defibrillate the patient, but use of 360 joules delivered in this fashion defibrillated the patient twice. Despite the protracted time of cardiac arrest, the patient recovered without sequelae. We report this case to demonstrate that VF refractory to transthoracic defibrillation may be converted by intracardiac shocks using a temporary pacing catheter without special equipment.