David Pham Bui

Dr. David Pham Bui


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 January 2017 in Clinical Infectious Diseases
Verified
Journal Article
Open access
PDF file
APAlvaro Proaño
Alvaro Proaño
MBMarjory A. Bravard
Marjory A. Bravard
Jose W LopezJose W Lopez
Jose W Lopez
GLGwenyth O. Lee
Gwenyth O. Lee
DBDavid Pham Bui
David Pham Bui
RGRobert H. Gilman
Robert H. Gilman
Cough is the major determinant of tuberculosis transmission. Despite this, there is a paucity of information regarding characteristics of cough frequency throughout the day and in response to tuberculosis therapy. Here we evaluate the circadian cycle of cough, cough frequency risk factors, and the impact of appropriate treatment on cough and bacillary load. We prospectively evaluated human immunodeficiency virus–negative adults (n = 64) with a new diagnosis of culture-proven, drug-susceptible pulmonary tuberculosis immediately prior to treatment and repeatedly until treatment day 62. At each time point, participant cough was recorded (n = 670) and analyzed using the Cayetano Cough Monitor. Consecutive coughs at least 2 seconds apart were counted as separate cough episodes. Sputum samples (n = 426) were tested with microscopic-observation drug susceptibility broth culture, and in culture-positive samples (n = 252), the time to culture positivity was used to estimate bacillary load. The highest cough frequency occurred from 1 pm to 2 pm, and the lowest from 1 am to 2 am (2.4 vs 1.1 cough episodes/hour, respectively). Cough frequency was higher among participants who had higher sputum bacillary load (P < .01). Pretreatment median cough episodes/hour was 2.3 (interquartile range [IQR], 1.2–4.1), which at 14 treatment days decreased to 0.48 (IQR, 0.0–1.4) and at the end of the study decreased to 0.18 (IQR, 0.0–0.59) (both reductions P < .001). By 14 treatment days, the probability of culture conversion was 29% (95% confidence interval, 19%–41%). Coughs were most frequent during daytime. Two weeks of appropriate treatment significantly reduced cough frequency and resulted in one-third of participants achieving culture conversion. Thus, treatment by 2 weeks considerably diminishes, but does not eliminate, the potential for airborne tuberculosis transmission.

6 January 2016 in The American Journal of Tropical Medicine and Hygiene
Verified
Journal Article
Closed access
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DBDavid Pham Bui
David Pham Bui
HBHeidi E Brown
Heidi E Brown
RHRobin B. Harris
Robin B. Harris
EOEyal Oren
Eyal Oren
Helicobacter pylori infection is among the most prevalent infections in the world and a key cause of gastric diseases; however, its route of transmission remains unclear. This study aimed to assess the potential for fecal–oral transmission of H. pylori by leveraging its association with a disease with known etiology. Utilizing serology data from the National Health and Nutrition Examination Survey (NHANES 1999; N = 6,347), the association between H. pylori and hepatitis A virus (HAV), a sensitive indicator for fecal–oral exposure, was assessed. Survey-weighted kappa and multiple logistic regression were used to quantify the association between H. pylori and HAV after controlling for age, sex, race, poverty, birthplace, crowding, smoking, and alcohol use. Concordant serological results were found among 69.8% of participants (survey-weighted κ = 0.30, 95% confidence interval [CI] = 0.26, 0.35). The adjusted odds of H. pylori seropositivity were over two times higher after adjusting for confounders (odds ratio = 2.27, 95% CI = 1.79, 2.87). Results from this study suggest H. pylori and HAV infections are strongly associated. Since HAV is primarily transmitted through the fecal–oral route, fecal–oral transmission may be an important pathway for H. pylori spread.

1 June 2018 in Accident Analysis & Prevention
Verified
Journal Article
Open access
DBDavid Pham Bui
David Pham Bui
SBSamantha Balland
Samantha Balland
CGCasey Giblin
Casey Giblin
AJAlesia M. Jung
Alesia M. Jung
SKSandy Kramer
Sandy Kramer
JBJefferey L. Burgess
Jefferey L. Burgess
Emergency service vehicle incidents (ESVI), including crashes, rollovers, and roadside struck-by-incidents, are a leading cause of occupational fatality and injury among firefighters and other emergency responders. Though there are numerous strategies and interventions to prevent ESVIs, the evidence base for these strategies is limited and dispersed. The goal of this study was to gather and present a review of evidence-based ESVI interventions. We searched five academic databases for articles published within the last decade featuring interventions to reduce or prevent ESVIs. We interviewed key informants from fire departments serving major metropolitan areas for additional interventions. Interventions from both sources were summarized and data on intervention effectiveness were reported when available. Sixty-five articles were included in the final review and 17 key informant interviews were completed. Most articles focused on vehicle engineering interventions (38%), followed by policy and administration interventions (26%), environmental engineering interventions (19%) and education or training (17%). Most key informants reported policy (49%) and training interventions (29%). Enhanced drivers' training and risk management programs were associated with 19-50% and 19-58% reductions in ESVIs, respectively. Only a limited number of interventions to address ESVIs had adequate outcome data. Based on the available data, training and risk management approaches may be particularly effective approaches to reducing ESVIs.

17 November 2018 in Traffic Injury Prevention
Verified
Journal Article
Open access
DBDavid Pham Bui
David Pham Bui
CHC. Hu
C. Hu
AJA. M. Jung
A. M. Jung
KPK. M. Pollack Porter
K. M. Pollack Porter
SGS. C. Griffin
S. C. Griffin
JBJ. L. Burgess
J. L. Burgess
Objective: Emergency service vehicle incidents are a leading cause of firefighter fatalities and are also hazardous to civilian road users. Modifiable driving behaviors may be associated with emergency service vehicle incidents. The goal of this study was to use telematics to identify driving behaviors associated with crashes in the fire service. Methods: Forty-three emergency service vehicles in 2 fire departments were equipped with telematics devices (12 in Department A and 31 in Department B). The devices collected vehicle coordinates, speed, and g forces, which were monitored for exceptions to driving rules established by the fire departments regarding speeding, harsh braking, and hard cornering. Fire department administrative reports were used to identify vehicles involved in crashes and merged with daily telematics data. Penalized logistic regression was used to identify driving rules associated with crashes. Least absolute shrinkage and selection operator (LASSO) regression was used to generate a telematics-based risk index for emergency service vehicle incidents. Results: Nearly 1.1 million km of driving data and 44 crashes were recorded among the 2 departments during the study. Harsh braking was associated with increased odds of crash in Department A (odds ratio [OR] = 2.22; 95% confidence interval [CI], 1.09–4.51) and Department B (OR = 1.55; 95% CI, 1.12–2.15). For every kilometer of nonemergency speeding, the odds of crash increased by 35% in Department A (OR = 1.35; 95% CI, 1.03–1.77) and by over 2-fold in Department B (OR = 2.09; 95% CI, 1.19–3.66). In Department B, hard cornering (OR = 1.14; 95% CI, 1.03–1.26) and emergency speeding (OR = 1.65; 95% CI, 1.06–2.57) were also associated with increased odds of crash. The final LASSO risk index model had a sensitivity of 73% and specificity of 57%. Conclusions: Harsh braking and excessive speeding were driving behaviors most associated with crash in the fire service. Telematics may be a useful tool for monitoring driver safety in the fire service.

1 June 2018 in Chest
Verified
Journal Article
Open access
APAlvaro Proaño
Alvaro Proaño
DBDavid Pham Bui
David Pham Bui
Jose W LopezJose W Lopez
Jose W Lopez
NVNancy M. Vu
Nancy M. Vu
MBMarjory A. Bravard
Marjory A. Bravard
EOEyal Oren
Eyal Oren
Cough frequency, and its duration, is a biomarker that can be used in low-resource settings without the need of laboratory culture and has been associated with transmission and treatment response. Radiologic characteristics associated with increased cough frequency may be important in understanding transmission. The relationship between cough frequency and cavitary lung disease has not been studied. We analyzed data in 41 adults who were HIV negative and had culture-confirmed, drug-susceptible pulmonary TB throughout treatment. Cough recordings were based on the Cayetano Cough Monitor, and sputum samples were evaluated using microscopic observation drug susceptibility broth culture; among culture-positive samples, bacillary burden was assessed by means of time to positivity. CT scans were analyzed by a US-board-certified radiologist and a computer-automated algorithm. The algorithm evaluated cavity volume and cavitary proximity to the airway. CT scans were obtained within 1 month of treatment initiation. We compared small cavities (≤ 7 mL) and large cavities (> 7 mL) and cavities located closer to (≤ 10 mm) and farther from (> 10 mm) the airway to cough frequency and cough cessation until treatment day 60. Cough frequency during treatment was twofold higher in participants with large cavity volumes (rate ratio [RR], 1.98; P = .01) and cavities located closer to the airway (RR, 2.44; P = .001). Comparably, cough ceased three times faster in participants with smaller cavities (adjusted hazard ratio [HR], 2.89; P = .06) and those farther from the airway (adjusted HR, 3.61;, P = .02). Similar results were found for bacillary burden and culture conversion during treatment. Cough frequency during treatment is greater and lasts longer in patients with larger cavities, especially those closer to the airway.

17 November 2017 in BMC Public Health
Verified
Journal Article
Open access
PDF file
DBDavid Pham Bui
David Pham Bui
KPKeshia Pollack Porter
Keshia Pollack Porter
SGStephanie Griffin
Stephanie Griffin
DFDustin D. French
Dustin D. French
AJAlesia Marie Jung
Alesia Marie Jung
JBJefferey Burgess
Jefferey Burgess
Emergency service vehicle crashes (ESVCs) are a leading cause of death in the United States fire service. Risk management (RM) is a proactive process for identifying occupational risks and reducing hazards and unwanted events through an iterative process of scoping hazards, risk assessment, and implementing controls. We describe the process, outputs, and lessons learned from the application of a proactive RM process to reduce ESVCs in US fire departments. Three fire departments representative of urban, suburban, and rural geographies, participated in a facilitated RM process delivered through focus groups and stakeholder discussion. Crash reports from department databases were reviewed to characterize the context, circumstances, hazards and risks of ESVCs. Identified risks were ranked using a risk matrix that considered risk likelihood and severity. Department-specific control measures were selected based on group consensus. Interviews, and focus groups were used to assess acceptability and utility of the RM process and perceived facilitators and barriers of implementation. Three to six RM meetings were conducted at each fire department. There were 7.4 crashes per 100 personnel in the urban department and 10.5 per 100 personnel in the suburban department; the rural department experienced zero crashes. All departments identified emergency response, backing, on scene struck by, driver distraction, vehicle/road visibility, and driver training as high or medium concerns. Additional high priority risks varied by department; the urban department prioritized turning and rear ending crashes; the suburban firefighters prioritized inclement weather/road environment and low visibility related crashes; and the rural volunteer fire department prioritized exiting station, vehicle failure, and inclement weather/road environment related incidents. Selected controls included new policies and standard operating procedures to reduce emergency response, cameras to enhance driver visibility while backing, and increased training frequency and enhanced training. The RM process was generally acceptable to department participants and considered useful. All departments reported that the focused and systematic analysis of crashes was particularly helpful. Implementation of controls was a commonly cited challenge. Proactive RM of ESVCs in three US fire departments was positively received and supported the establishment of interventions tailored to each department’s needs and priorities.