Deciphering data anomalies in BioSense.

INTRODUCTION: Since June 2004, CDC's BioIntelligence Center has monitored daily nationwide syndromic data by using the BioSense surveillance application. OBJECTIVES: The BioSense application has been monitored by a team of full-time CDC analysts. This report examines their role in identifying and deciphering data anomalies. It also discusses the limitations of the current surveillance application, lessons learned, and potential next steps to improve national syndromic surveillance methodology. METHODS: Data on clinical diagnoses (International Classification of Diseases, Ninth Revision, Clinical Modifications [ICD-9-CM]) and medical procedures (CPT codes) are provided by Department of Veterans Affairs and Department of Defense ambulatory-care clinics; data on select sales of over-the-counter health-care products are provided by participating retail pharmacies; and data on laboratory tests ordered are provided by Laboratory Corporation of America, Inc. All data are filtered to exclude information irrelevant to syndromic surveillance. RESULTS: During June-November 2004, of the approximately 160 data anomalies examined, no events involving disease outbreaks or deliberate exposure to a pathogen were detected. Data anomalies were detected by using a combination of statistical algorithms and analytical visualization features. The anomalies primarily reflected unusual changes in either daily data volume or in types of clinical diagnoses and procedures. This report describes steps taken in routine monitoring, including 1) detecting data anomalies, 2) estimating geographic and temporal scope of the anomalies, 3) gathering supplemental facts, 4) comparing data from multiple data sources, 5) developing hypotheses, and 6) ruling out or validating the existence of an actual event. To be useful for early detection, these steps must be completed quickly (i.e., in hours or days). Anomalies described are attributable to multiple causes, including miscoded data, effects of retail sales promotions, and smaller but explainable signals. CONCLUSION: BioSense requires an empirical learning curve to make the best use of the public health data it contains. This process can be made more effective by continued improvements to the user interface and collective input from local public health partners.

Holeboard performance of rats after hippocampal lesions and treatment with nimodipine.

Rats were taught to select eight holes in a 4 x 4 holeboard for food reinforcements. Upon reaching criterion, they were given subtotal lesions of the anterior hippocampus or sham operations. They then received either the calcium channel blocker, nimodipine, or vehicle alone. Retention testing revealed a significant main effect of lesion and evidence for nimodipine reducing this effect. These data are consistent with previous findings from this laboratory in which it was demonstrated that nimodipine can enhance performance on higher cognitive tasks after hippocampal damage.

A comparison of laryngeal mask airway with tracheal tube for intra-ocular ophthalmic surgery.

The use of the laryngeal mask was compared with tracheal intubation in 30 patients who underwent intra-ocular ophthalmic surgery and who received intravenous anaesthesia with propofol. Changes in intra-ocular pressure, heart rate and mean arterial pressure after the insertion of the laryngeal mask airway or the tracheal tube were not significantly different. However, at the end of the procedure, a significantly higher percentage of patients with a tracheal tube coughed, reacted to head movement and suffered breath-holding. In addition, significantly more patients in this group complained of a sore throat (p less than 0.05). During intravenous propofol anaesthesia, the laryngeal mask airway does not offer any advantage over tracheal intubation in the control of intra-ocular pressure for intra-ocular ophthalmic surgery. However, there were fewer complications immediately following surgery in the laryngeal mask group.

A fast-acting humoral factor mediates pressor hyperresponsiveness in deoxycorticosterone-salt rabbits.

Six rabbits were sham operated and were given water to drink (sham-water group); six additional rabbits were sham operated and were given saline to drink (sham-salt group); another six rabbits received an implant of deoxycorticosterone (DOCA) and were given water to drink (DOCA-water group); a final group of six rabbits received implants of DOCA and were given saline to drink (DOCA-salt group). Two weeks later, all four groups of rabbits had approximately the same mean arterial pressures, and the sham-salt, DOCA-water, and DOCA-salt groups all had plasma renin activity values less than the sham-water group. The DOCA-salt group had greater pressor responses to norepinephrine (NE) at several doses than did the other three groups of rabbits. In another group of six sham-water and six DOCA-salt rabbits, measurements of cardiac output before and during infusions of NE at 800 ng/min/kg body wt revealed no changes in cardiac output before or during NE infusion, but the DOCA-salt group had significantly greater increases in mean arterial pressure and total peripheral resistance during NE than did the sham-water group. In another group of six DOCA-salt rabbits, the pressor response to several doses of NE were determined during infusion of the angiotensin II (AII) antagonist, [Sar1, Ile8] AII; this AII antagonist failed to alter the enhanced pressor responses to NE. A final experiment examined pressor responses to NE in six normal rabbits before and after cross circulation of blood with six DOCA-salt rabbits. After blood cross circulation the normal rabbits had exaggerated pressor responses to NE at 5, 15, and 30 min, but not at 60 min. Similar cross-circulation experiments between six pairs of normal rabbits did not show any transfer of pressor hyperresponsiveness. These studies indicated that pressor and vascular hyperresponsiveness in DOCA-salt rabbits is conveyed by a fast-acting hormonal factor and that AII probably is not involved in mediating this hyperresponsiveness.