Effect of a mobile health, sensor-driven asthma management platform on asthma control.

BACKGROUND: Asthma inflicts a significant health and economic burden in the United States. Self-management approaches to monitoring and treatment can be burdensome for patients. OBJECTIVE: To assess the effect of a digital health management program on asthma outcomes. METHODS: Residents of Louisville, Kentucky, with asthma were enrolled in a single-arm pilot study. Participants received electronic inhaler sensors that tracked the time, frequency, and location of short-acting ß-agonist (SABA) use. After a 30-day baseline period during which reference medication use was recorded by the sensors, participants received access to a digital health intervention designed to enhance self-management. Changes in outcomes, including mean daily SABA use, symptom-free days, and asthma control status, were compared among the initial 30-day baseline period and all subsequent months of the intervention using mixed-model logistic regressions and χ2 tests. RESULTS: The mean number of SABA events per participant per day was 0.44 during the control period and 0.27 after the first month of the intervention, a 39% reduction. The percentage of symptom-free days was 77% during the baseline period and 86% after the first month, a 12% improvement. Improvement was observed throughout the study; each intervention month demonstrated significantly lower SABA use and higher symptom-free days than the baseline month (P < .001). Sixty-nine percent had well-controlled asthma during the baseline period, 67% during the first month of the intervention. Each intervention month demonstrated significantly higher percentages than the baseline month (P < .001), except for month 1 (P = .80). CONCLUSION: A digital health asthma management intervention demonstrated significant reductions in SABA use, increased number of symptom-free days, and improvements in asthma control. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02162576.

Understanding socioeconomic and racial differences in adult lung function.

RATIONALE: The contribution of socioeconomic factors to racial differences in the distribution of lung function is not well understood. OBJECTIVES: We investigated the contribution of socioeconomic factors to racial differences in FEV1 using statistical tools that allow for examination across the population distribution of FEV1. METHODS: We compared FEV1 for white and African-American participants (aged 20-80 yr) in NHANES III with greater than or equal to two acceptable maneuvers to a restricted sample following the routine exclusion criteria used to derive population reference equations. Ordinary least squares and quantile regression analyses using spirometric, anthropometric, and socioeconomic data (high school completion) were performed separately by sex for both data sets. MEASUREMENTS AND MAIN RESULTS: In the entire sample with acceptable spirometry (n » 9,658), high school completion was associated with a mean 69.13-ml increase in FEV1 for males (P , 0.05) and a mean 50.75-ml increase in FEV1 for females (P , 0.01). In quantile regression analysis, we observed a significant racial difference in the association of high school completion with FEV1 among both sexes that varied across the distribution; college completion was associated with an additional increase in FEV1 for white males (70.36-250.76 ml) and white females (57.87-317.77 ml). Routine exclusion criteria differentially excluded individuals by age, race, and education. In the restricted sample (n » 2,638), the association with high school completion was not significant. CONCLUSIONS: High school completion is associated with racially patterned improvements in the FEV1 of adults in the general population. The application of routine exclusion criteria leads to underestimates of the role of high school completion on FEV1.

Identifying impacts of air pollution on subacute asthma symptoms using digital medication sensors.

BACKGROUND: Objective tracking of asthma medication use and exposure in real-time and space has not been feasible previously. Exposure assessments have typically been tied to residential locations, which ignore exposure within patterns of daily activities. METHODS: We investigated the associations of exposure to multiple air pollutants, derived from nearest air quality monitors, with space-time asthma rescue inhaler use captured by digital sensors, in Jefferson County, Kentucky. A generalized linear mixed model, capable of accounting for repeated measures, over-dispersion and excessive zeros, was used in our analysis. A secondary analysis was done through the random forest machine learning technique. RESULTS: The 1039 participants enrolled were 63.4% female, 77.3% adult (>18) and 46.8% White. Digital sensors monitored the time and location of over 286 980 asthma rescue medication uses and associated air pollution exposures over 193 697 patient-days, creating a rich spatiotemporal dataset of over 10 905 240 data elements. In the generalized linear mixed model, an interquartile range (IQR) increase in pollutant exposure was associated with a mean rescue medication use increase per person per day of 0.201 [95% confidence interval (CI): 0.189-0.214], 0.153 (95% CI: 0.136-0.171), 0.131 (95% CI: 0.115-0.147) and 0.113 (95% CI: 0.097-0.129), for sulphur dioxide (SO2), nitrogen dioxide (NO2), fine particulate matter (PM2.5) and ozone (O3), respectively. Similar effect sizes were identified with the random forest model. Time-lagged exposure effects of 0-3 days were observed. CONCLUSIONS: Daily exposure to multiple pollutants was associated with increases in daily asthma rescue medication use for same day and lagged exposures up to 3 days. Associations were consistent when evaluated with the random forest modelling approach.

Geospatial-temporal analysis of the impact of ozone on asthma rescue inhaler use.

RATIONALE: Asthma is one of the most common chronic respiratory diseases in the United States. Several outdoor air pollutants have been associated with asthma morbidity. Previous studies of the effects of short-term air pollution exposure have been limited by potential exposure misclassification and limited spatial and temporal resolution of asthma outcome measures. OBJECTIVES: We aimed to assess the association of short-term air pollutant exposure with the use of short-acting beta-2 agonists (SABA) for asthma by monitoring the time and place of occurrence with electronic medication monitors. METHODS: In a cohort of adults and children with asthma (n = 287; 60% female), we deployed electronic medication monitors fitted to metered-dose inhalers to monitor SABA use, capturing the date, time and location of use. We assigned pollutant exposures based on each actuation's time and location (4-h mean measures for ozone and particulate matter of 2.5 µm or smaller (PM2.5)), assessed associations using generalized linear models and explored age-specific effects. MEASUREMENTS AND MAIN RESULTS: Ambient ozone exposure was positively associated with SABA use (p = 0.01). Age-specific associations were identified (interaction p = 0.01), with a larger increase in SABA use for children (11.3%; 95% CI: 7.0%-18.2%) than adults (8.4%; 95% CI: 6.4%-11.0%) per IQR increase of ozone (16.8 ppb). CONCLUSIONS: These findings support existing evidence that short-term exposure to ozone can cause morbidity in individuals with asthma, and suggest that ozone exposures below the current U.S. EPA standard may be associated with increased SABA use.

Acute health effects after exposure to chlorine gas released after a train derailment.

In January 2005, a train derailment on the premises of a textile mill in South Carolina released 42 to 60 tons of chlorine gas in the middle of a small town. Medical records and autopsy reports were reviewed to describe the clinical presentation, hospital course, and pathology observed in persons hospitalized or deceased as a result of chlorine gas exposure. Eight persons died before reaching medical care; of the 71 persons hospitalized for acute health effects as a result of chlorine exposure, 1 died in the hospital. The mean age of the hospitalized persons was 40 years (range, 4 months-76 years); 87% were male. The median duration of hospitalization was 4 days (range, 1-29 days). Twenty-five (35%) persons were admitted to the intensive care unit; the median length of stay was 3 days. Many surviving victims developed significant pulmonary signs and severe airway inflammation; 41 (58%) hospitalized persons met PO2/FiO2 criteria for acute respiratory distress syndrome or acute lung injury. During their hospitalization, 40 (57%) developed abnormal x-ray findings, 74% of those within the first day. Hypoxia on room air and PO2/FiO2 ratio predicted severity of outcome as assessed by the duration of hospitalization and the need for intensive care support. This community release of chlorine gas caused widespread exposure and resulted in significant acute health effects and substantial health care requirements. Pulse oximetry and arterial blood gas analysis provided early indications of outcome severity.

Passive Monitoring of Short-Acting Beta-Agonist Use via Digital Platform in Patients With Chronic Obstructive Pulmonary Disease: Quality Improvement Retrospective Analysis.

BACKGROUND: Digital health programs assist patients with chronic obstructive pulmonary disease (COPD) to better manage their disease. Technological and adoption barriers have been perceived as a limitation. OBJECTIVE: The aim of the research was to evaluate a digital quality improvement pilot in Medicare-eligible patients with COPD. METHODS: COPD patients were enrolled in a digital platform to help manage their medications and symptoms as part of their routine clinical care. Patients were provided with electronic medication monitors (EMMs) to monitor short-acting beta-agonist (SABA) use passively and a smartphone app to track use trends and receive feedback. Providers also had access to data collected via a secure website and were sent email notifications if a patient had a significant change in their prescribed inhaler use. Providers then determined if follow-up was needed. Change in SABA use and feasibility outcomes were evaluated at 3, 6, and 12 months. RESULTS: A total of 190 patients enrolled in the pilot. At 3, 6, and 12 months, patients recorded significant reductions in daily and nighttime SABA use and increases in SABA-free days (all P<.001). Patient engagement, as measured by the ratio of daily active use to monthly active use, was >90% at both 6 and 12 months. Retention at 6 months was 81% (154/190). Providers were sent on average two email notifications per patient during the 12-month program. CONCLUSIONS: A digital health program integrated as part of standard clinical practice was feasible and had low provider burden. The pilot demonstrated significant reduction in SABA use and increased SABA-free days among Medicare-eligible COPD patients. Further, patients readily adopted the digital platform and demonstrated strong engagement and retention rates at 6 and 12 months.

Breath acidification in adolescent runners exposed to atmospheric pollution: a prospective, repeated measures observational study.

BACKGROUND: Vigorous outdoors exercise during an episode of air pollution might cause airway inflammation. The purpose of this study was to examine the effects of vigorous outdoor exercise during peak smog season on breath pH, a biomarker of airway inflammation, in adolescent athletes. METHODS: We measured breath pH both pre- and post-exercise on ten days during peak smog season in 16 high school athletes engaged in daily long-distance running in a downwind suburb of Atlanta. The association of post-exercise breath pH with ambient ozone and particulate matter concentrations was tested with linear regression. RESULTS: We collected 144 pre-exercise and 146 post-exercise breath samples from 16 runners (mean age 14.9 years, 56% male). Median pre-exercise breath pH was 7.58 (interquartile range: 6.90 to 7.86) and did not change significantly after exercise. We observed no significant association between ambient ozone or particulate matter and post-exercise breath pH. However both pre- and post-exercise breath pH were strikingly low in these athletes when compared to a control sample of 14 relatively sedentary healthy adults and to published values of breath pH in healthy subjects. CONCLUSION: Although we did not observe an acute effect of air pollution exposure during exercise on breath pH, breath pH was surprisingly low in this sample of otherwise healthy long-distance runners. We speculate that repetitive vigorous exercise may induce airway acidification.

Digital Health Intervention for Asthma: Patient-Reported Value and Usability.

BACKGROUND: Although digital health tools are increasingly recognized as effective in improving clinical outcomes such as asthma control and medication adherence, few studies have assessed patient experiences and perception of value. OBJECTIVE: The aim of this study was to evaluate patient satisfaction, perception of usability and value, and desire to continue after 12 months of using a digital health intervention to support asthma management. METHODS: Participants were enrolled in a randomized controlled study evaluating the impact of a digital health platform for asthma management. Participants used electronic inhaler sensors to track medication use and accessed their information in a digital health platform. Electronic surveys were administered to intervention arm participants aged 12 years and older after 12 months of use. The survey assessed asthma control, patient satisfaction with the sensor device, and perception of the usability and value of the digital health platform through closed-ended and open-ended questions. Logistic regression models were used to assess the impact of participants' characteristics on survey completion, satisfaction, and perception of value. RESULTS: Of the 207 intervention arm participants aged 12 years and older, 89 submitted survey responses (42.9% response rate). Of these 89 participants, 70 reported being very satisfied (79%, 70/89) or somewhat satisfied (20%, 18/89) with the inhaler sensor device. Moreover, 93% (83/89) expressed satisfaction with the reports, and 90% (80/89) found the information from the reports useful for learning about their asthma. In addition, 72% (64/89) of the participants reported that they were interested in continuing to use the sensor and platform beyond the study. There were no significant differences in satisfaction with the device or the platform across participants' characteristics, including device type, age, sex, insurance type, asthma control, or syncing history; however, participants with smartphones and longer participation were more likely to take the survey. CONCLUSIONS: Electronic sensors and a digital health platform were well received by participants who reported satisfaction and perceived value. These results were consistent across multiple participants' characteristics. These findings can add to a limited literature to keep improving digital health interventions and ensure the meaningful and enduring impact on patient outcomes.

Impact of a digital health intervention on asthma resource utilization.

Digital health interventions have been associated with reduced rescue inhaler use and improved controller medication adherence. This quality improvement project assessed the benefit of these interventions on asthma-related healthcare utilizations, including hospitalizations, emergency department (ED) utilization and outpatient visits. The intervention consisted of electronic medication monitors (EMMs) that tracked rescue and controller inhaler medication use, and a digital health platform that presented medication use information and asthma control status to patients and providers. In 224 study patients, the number of asthma-related ED visits and combined ED and hospitalization events 365 days pre- to 365 days post-enrollment to the intervention significantly decreased from 11.6 to 5.4 visits (p < 0.05) and 13.4 to 5.8 events (p < 0.05) per 100 patient-years, respectively. This digital health intervention was successfully incorporated into routine clinical practice and was associated with lower rates of asthma-related hospitalizations and ED visits.

Carbon monoxide poisoning in Florida during the 2004 hurricane season.

BACKGROUND: During August-September 2004, four major hurricanes hit Florida, resulting in widespread power outages affecting several million households. Carbon monoxide (CO) poisonings during this period were investigated to identify ways to prevent future poisoning. METHODS: Medical records from ten hospitals (two with hyperbaric oxygen chambers) were reviewed to identify individuals diagnosed with unintentional CO poisoning between August 13 and October 15, 2004. Multiple attempts were made to interview one person from each nonfatal incident. Medical examiner records and reports of investigations conducted by the U.S. Consumer Product Safety Commission of six fatal poisonings from five additional incidents were also reviewed. RESULTS: A total of 167 people treated for nonfatal CO poisoning were identified, representing 51 incidents. A portable, gasoline-powered generator was implicated in nearly all nonfatal incidents and in all fatal poisonings. Generators were most often located outdoors, followed by inside the garage, and inside the home. Telephone interviews with representatives of 35 (69%) incidents revealed that concerns about theft or exhaust most often influenced the choice of location. Twenty-six (74%) households did not own a generator before the hurricanes, and 86% did not have a CO detector at the time of the poisoning. Twenty-one (67%) households reported reading or hearing CO education messages before the incident. CONCLUSIONS: Although exposure to public education messages may have encouraged more appropriate use of generators, a substantial number of people were poisoned even when the devices were operated outdoors. Additional educational efforts and engineering solutions that reduce CO emission from generators should be the focus of public health activities.

Panel classification of self-reported exposure histories: a useful exposure index after a mass-casualty event.

OBJECTIVE: Although rapid epidemiologic investigations of toxic exposures require estimates of individual exposure levels, objective measures of exposure are often unavailable. We investigated whether self-reported exposure histories, when reviewed and classified by a panel of raters, provided a useful exposure metric. METHODS: A panel reviewed exposure histories as reported by people who experienced a chlorine release. The panelists received no information about health-care requirements or specific health effects. To each exposure case, each panelist assigned one of five possible exposure severity ratings. When assigned ratings were not in initial agreement, the panelists discussed the case and assigned a consensus rating. Percent agreement and kappa statistics assessed agreement among panelists, Kendall's W measured agreement among panelists in their overall ordering of the exposure histories, and Spearman's rho compared the resultant rankings with individual health outcome. RESULTS: In 48% of the cases, the panelists' initial ratings agreed completely. Overall, initial ratings for a given case matched the consensus rating 69% to 89% of the time. Pair-wise comparisons revealed 85% to 95% agreement among panelists, with weighted kappa statistics between 0.69 and 0.83. In their overall ranking of the exposure histories, the panelists reached significant agreement (W = 0.90, p < 0.0001). Disagreement arose most frequently regarding probable chlorine concentration and duration of exposure. This disagreement was most common when panelists differentiated between adjacent categories of intermediate exposure. Panel-assigned exposure ratings significantly correlated with health outcome (Spearman's rho = 0.56; p < 0.0001). CONCLUSION: Epidemiologists and public health practitioners can elicit and review self-reported exposure histories and assign exposure severity ratings that predict medical outcome. When objective markers of exposure are unavailable, panel-assigned exposure ratings may be useful for rapid epidemiologic investigations.

Rapid assessment of exposure to chlorine released from a train derailment and resulting health impact.

OBJECTIVES: After a train derailment released approximately 60 tons of chlorine from a ruptured tanker car, a multiagency team performed a rapid assessment of the health impact to determine morbidity caused by the chlorine and evaluate the effect of this mass-casualty event on health-care facilities. METHODS: A case was defined as death or illness related to chlorine exposure. Investigators gathered information on exposure, treatment received, and outcome through patient questionnaires and medical record review. An exposure severity rating was assigned to each patient based on description of exposure, distance from derailment, and duration of exposure. A case involving death or hospitalization > or = 3 nights was classified as a severe medical outcome. Logistic regression was used to examine factors associated with severe medical outcomes. RESULTS: Nine people died, 72 were hospitalized in nine hospitals, and 525 were examined as outpatients. Fifty-one people (8%) had a severe medical outcome. Of 263 emergency department visits within 24 hours of the incident, 146 (56%) were in Augusta, Georgia; at least 95 patients arrived at facilities in privately owned vehicles. Patients with moderate-to-extreme exposure were more likely to experience a severe medical outcome (relative risk: 15.2; 95% confidence interval 4.8, 47.8) than those with a lower rating. CONCLUSIONS: The rapid investigation revealed significant morbidity and mortality associated with an accidental release of chlorine gas. Key findings that should be addressed during facility, community, state, and regional mass-casualty planning include self-transport of symptomatic people for medical care and impact on health-care facilities over a wide geographic area.

Evaluation of a cross-linked acellular porcine dermal patch for rotator cuff repair augmentation in an ovine model.

In this study we evaluated 2 commercially available rotator cuff repair augmentation patches in an in vivo sheep model using mechanical testing and histologic techniques. Bilateral infraspinatus tears were created and repaired in 2 groups of 8 adult ewes. Each group (killed at 9 or 24 weeks) included 5 repaired with suture alone, 6 repaired and augmented with a cross-linked acellular porcine dermal (PD) patch (Zimmer Collagen Repair Patch), and 5 repaired and augmented with a porcine small intestine submucosa (SIS) patch (Restore Orthobiologic Soft Tissue Implant; DePuy Orthopaedics). At 3 weeks, sheep with suture repair and an SIS patch had significant elevation of plasma fibrinogen levels (P < .05) whereas sheep with suture repair and a PD patch elicited no elevation in plasma fibrinogen levels. At 9 weeks, the mean failure load was 201 +/- 60 lb for suture repairs, 182 +/- 63 lb for PD repairs, and 137 +/- 16 lb for SIS repairs. Within any individual sheep, the shoulder undergoing PD repair always had a higher failure load than the contralateral suture or shoulder undergoing SIS repair. At 9 weeks, macrophages were seen on all PD surfaces whereas most of the SIS materials were resorbed. At 24 weeks, failure loads were identical between groups. Macrophages had disappeared from the PD groups, and integration of the PD patch into the surrounding tissue with vascular and fibroblastic invasion was seen. For the SIS group, diverse tissue types (including ectopic bone) were seen.

Comparison of insertion characteristics of two types of hydroxyapatite-coated and uncoated positive profile transfixation pins in the third metacarpal bone of horses.

OBJECTIVE: To determine the effect of 2 hydroxyapatite pin coatings on heat generated at the bone-pin interface and torque required for insertion of transfixation pins into cadaveric equine third metacarpal bone. SAMPLE POPULATION: Third metacarpal bone pairs from 27 cadavers of adult horses. PROCEDURES: Peak temperature of the bone at the cis-cortex and the hardware and pin at the trans-cortex was measured during insertion of a plasma-sprayed hydroxyapatite (PSHA)-coated, biomimetic hydroxyapatite (BMHA)-coated, or uncoated large animal transfixation pin. End-insertional torque was measured for each pin. The bone-pin interface was examined grossly and histologically for damage to the bone and coating. RESULTS: The BMHA-coated transfixation pins had similar insertion characteristics to uncoated pins. The PSHA-coated pins had greater mean peak bone temperature at the cis-cortex and greater peak temperature at the trans-cortex (70.9 +/- 6.4(o)C) than the uncoated pins (38.7 +/- 8.4(o)C). The PSHA-coated pins required more insertional torque (10,380 +/- 5,387.8 Nmm) than the BMHA-coated pins (5,123.3 +/- 2,296.9 Nmm). Four of the PSHA-coated pins became immovable after full insertion, and 1 gross fracture occurred during insertion of this type of pin. CONCLUSIONS AND CLINICAL RELEVANCE: The PSHA coating was not feasible for use without modification of presently available pin hardware. The BMHA-coated pins performed similarly to uncoated pins. Further testing is required in an in vivo model to determine the extent of osteointegration associated with the BMHA-coated pins in equine bone.

Feasibility of Deploying Inhaler Sensors to Identify the Impacts of Environmental Triggers and Built Environment Factors on Asthma Short-Acting Bronchodilator Use.

BACKGROUND: Epidemiological asthma research has relied upon self-reported symptoms or healthcare utilization data, and used the residential address as the primary location for exposure. These data sources can be temporally limited, spatially aggregated, subjective, and burdensome for the patient to collect. OBJECTIVES: First, we aimed to test the feasibility of collecting rescue inhaler use data in space-time using electronic sensors. Second, we aimed to evaluate whether these data have the potential to identify environmental triggers and built environment factors associated with rescue inhaler use and to determine whether these findings would be consistent with the existing literature. METHODS: We utilized zero-truncated negative binomial models to identify triggers associated with inhaler use, and implemented three sensitivity analyses to validate our findings. RESULTS: Electronic sensors fitted on metered dose inhalers tracked 5,660 rescue inhaler use events in space and time for 140 participants from 13 June 2012 to 28 February 2014. We found that the inhaler sensors were feasible in passively collecting objective rescue inhaler use data. We identified several environmental triggers with a positive and significant association with inhaler use, including: AQI, PM10, weed pollen, and mold. Conversely, the spatial distribution of tree cover demonstrated a negative and significant association with inhaler use. CONCLUSIONS: Utilizing a sensor to capture the signal of rescue inhaler use in space-time offered a passive and objective signal of asthma activity. This approach enabled detailed analyses to identify environmental triggers and built environment factors that are associated with asthma symptoms beyond the residential address. The application of these new technologies has the potential to improve our surveillance and understanding of asthma. Citation: Su JG, Barrett MA, Henderson K, Humblet O, Smith T, Sublett JW, Nesbitt L, Hogg C, Van Sickle D, Sublett JL. 2017. Feasibility of deploying inhaler sensors to identify the impacts of environmental triggers and built environment factors on asthma short-acting bronchodilator use. Environ Health Perspect 125:254-261; http://dx.doi.org/10.1289/EHP266.

Safety of, and biological and functional response to, a novel metallic implant for the management of focal full-thickness cartilage defects: Preliminary assessment in an animal model out to 1 year.

Focal full-thickness cartilage lesions of the human medial femoral condyle (MFC) can cause pain and functional impairment. Affected middle-aged patients respond unpredictably to existing treatments and knee arthroplasty may be required, prompting risk of revision. This study assesses the safety of, and biological and functional response to, a metallic resurfacing implant which may delay or obviate the need for traditional arthroplasty. The anatomic contour of the surgically exposed MFC of six adult goats was digitally mapped and an 11 mm diameter full-thickness osteochondral defect was created. An anchor-based Co-Cr resurfacing implant, matching the mapped articular contour, was implanted. Each goat's contralateral unoperated femorotibial joint was used as a control. Postoperative outcome was assessed by lameness examination, radiography, arthroscopy, synoviocentesis, necropsy, and histology up to 26 (n = 3) or 52 (n = 3) weeks. By postoperative week (POW) 4, goats demonstrated normal range of motion, no joint effusion, and only mild lameness in the operated limb. By POW 26 the animals were sound with only occasional very mild lameness. Arthroscopy at POW 14 revealed moderate synovial inflammation and a chondral membrane extending centrally across the implant surface. Radiographs at POWs 14 to 52 implied implant stability in the operated joints, as well as subchondral bone remodeling and mild exostosis formation in the operated and contralateral unoperated joints of some goats. By POW 26, histology revealed new trabecular bone abutting the implant. At POWs 26 and 52 MFC cartilage was metachromatic and intact in the operated and unoperated femorotibial joints. Proximal tibiae of some operated and unoperated limbs demonstrated limited subchondral bone remodeling and foci of articular cartilage fibrillation and thinning. The chondral membrane crossing the prosthesis possessed a metachromatic matrix containing singular and clustered chondrocytes. Our data imply the safety, biocompatibility, and functionality of the implant. Focal articular damage was documented in the operated joints at POWs 26 and 52, but lesions were much reduced over those previously reported in untreated defects. Expanded animal or preclinical human studies are justified.

Gentamicin concentrations in synovial fluid obtained from the tarsocrural joints of horses after implantation of gentamicin-impregnated collagen sponges.

OBJECTIVE: To determine synovial fluid gentamicin concentrations and evaluate adverse effects on the synovial membrane and articular cartilage of tarsocrural joints after implantation of a gentamicin-impregnated collagen sponge. ANIMALS: 6 healthy adult mares. PROCEDURES: A purified bovine type I collagen sponge impregnated with 130 mg of gentamicin was implanted in the plantarolateral pouch of 1 tarsocrural joint of each horse, with the contralateral joint used as a sham-operated control joint. Gentamicin concentrations in synovial fluid and serum were determined for 120 hours after implantation by use of a fluorescence polarization immunoassay. Synovial membrane and cartilage specimens were collected 120 hours after implantation and evaluated histologically. RESULTS: Median peak synovial fluid gentamicin concentration of 168.9 microg/mL (range, 115.6 to 332 microg/mL) was achieved 3 hours after implantation. Synovial fluid gentamicin concentrations were < 4 microg/mL by 48 hours. Major histologic differences were not observed in the synovial membrane between control joints and joints implanted with gentamicin-impregnated sponges. Safranin-O fast green stain was not reduced in cartilage specimens obtained from treated joints, compared with those from control joints. CONCLUSIONS AND CLINICAL RELEVANCE: Implantation of a gentamicin-impregnated collagen sponge in the tarsocrural joint of horses resulted in rapid release of gentamicin, with peak concentrations > 20 times the minimum inhibitory concentration reported for common pathogens that infect horses. A rapid decrease in synovial fluid gentamicin concentrations was detected. The purified bovine type I collagen sponges did not elicit substantial inflammation in the synovial membrane or cause mechanical trauma to the articular cartilage.

Presentation and treatment of asthma among native children in southwest Alaska delta.

Our objective was to determine if a different presentation of asthma among Eskimo children in southwest Alaska influenced treatment for asthma. Data regarding symptoms, medication use, and hospitalization were obtained from the medical records of 58 Eskimo children diagnosed with asthma. Half of the children also had a diagnosis of chronic lung disease (CLD), and 57% had a history of allergies. CLD was associated with significantly more visits for wheeze (P=0.02), asthma (P <0.005), and lower respiratory tract illnesses (P <0.005), and a greater incidence (P <0.005) and frequency (P <0.005) of hospitalizations. Allergy status showed no similar relation with utilization of health services. Inhaled corticosteroids were prescribed for a minority (38%) of these asthmatic children. Allergic children tended to be more likely to receive inhaled steroids, and they received significantly more prescriptions for inhaled steroids compared to children without allergies. Those with CLD only were no more likely to receive inhaled steroids than other children, despite their higher incidence of hospitalization. Although the proportion of children with CLD or allergy did not differ significantly by village, there were significant regional differences in healthcare utilization and medication use. In conclusion, while CLD was the primary determinant of healthcare utilization among these native children with asthma, only allergic children with CLD were more likely to receive inhaled steroids.