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Papers by David Chong

Critical Care Explorations, 2020

Objectives: Dietary fiber increases the abundance of bacteria that metabolize fiber into short-ch... more Objectives: Dietary fiber increases the abundance of bacteria that metabolize fiber into short-chain fatty acids and confers resistance against gut colonization with multidrug-resistant bacteria. This pilot trial estimated the effect of fiber on gut short-chain fatty acid–producing bacteria in the ICU. Design: Randomized, controlled, open label trial. Setting: Medical ICU. Patients: Twenty ICU adults receiving broad-spectrum IV antibiotics for sepsis. Intervention: 1:1 randomization to enteral nutrition with mixed soy- and oat-derived fiber (14.3 g fiber/L) versus calorie- and micronutrient-identical enteral nutrition with 0 g/L fiber. Measurements: Rectal swabs and whole stools were collected at baseline and on study Days 3, 7, 14, and 30. The primary outcome was within-individual change in the cumulative relative abundance of short-chain fatty acid–producing taxa from baseline to Day 3 based on 16S sequencing of rectal swabs. The secondary outcome was Day 3 cumulative short-chain ...

Open Forum Infectious Diseases, 2018

Background In critically ill patients, rectal colonization with VRE is associated with an increas... more Background In critically ill patients, rectal colonization with VRE is associated with an increased risk for nosocomial infection or death. In mice, fecal transplantation of Blautia producta directly inhibits VRE growth and leads to clearance of VRE. We performed a prospective, intensive care unit (ICU)-based study to evaluate the relationship between B. producta and VRE. We also sought to determine the relationship between VRE, MRSA, and other common MDR bacteria. Methods This study included 97 adults newly admitted to the ICU between February 2015 and June 2016. Rectal swabs were obtained at time of ICU admission and 72 hours later. VRE rectal colonization status was determined categorically for each sample by culture on selective media. Specimens were also cultured for methicillin-resistant Staphylococcus aureus (MRSA) and for MDR Gram-negatives, defined as those with nonsusceptibility to 3 or more antibiotic classes. 16S rRNA gene sequencing was performed and the relative abunda...

Intensive care medicine, Jan 23, 2018

Loss of colonization resistance within the gastrointestinal microbiome facilitates the expansion ... more Loss of colonization resistance within the gastrointestinal microbiome facilitates the expansion of pathogens and has been associated with death and infection in select populations. We tested whether gut microbiome features at the time of intensive care unit (ICU) admission predict death or infection. This was a prospective cohort study of medical ICU adults. Rectal surveillance swabs were performed at admission, selectively cultured for vancomycin-resistant Enterococcus (VRE), and assessed using 16S rRNA gene sequencing. Patients were followed for 30 days for death or culture-proven bacterial infection. Of 301 patients, 123 (41%) developed culture-proven infections and 76 (25%) died. Fecal biodiversity (Shannon index) did not differ based on death or infection (p = 0.49). The presence of specific pathogens at ICU admission was associated with subsequent infection with the same organism for Escherichia coli, Pseudomonas spp., Klebsiella spp., and Clostridium difficile, and VRE at ad...

PloS one, 2018

Commensal gastrointestinal bacteria resist the expansion of pathogens and are lost during critica... more Commensal gastrointestinal bacteria resist the expansion of pathogens and are lost during critical illness, facilitating pathogen colonization and infection. We performed a prospective, ICU-based study to determine risk factors for loss of gut colonization resistance during the initial period of critical illness. Rectal swabs were taken from adult ICU patients within 4 hours of admission and 72 hours later, and analyzed using 16S rRNA gene sequencing and selective culture for vancomycin-resistant Enterococcus (VRE). Microbiome data was visualized using principal coordinate analyses (PCoA) and assessed using a linear discriminant analysis algorithm and logistic regression modeling. 93 ICU patients were analyzed. At 72 hours following ICU admission, there was a significant decrease in the proportion of Clostridial Clusters IV/XIVa, taxa that produce short chain fatty acids (SCFAs). At the same time, there was a significant expansion in Enterococcus. Decreases in Cluster IV/XIVa Clostr...

B31. COMPLICATING INFECTIONS: INFLUENZA AND RHINOVIRUS, 2011

Seminars in respiratory and critical care medicine, 2015

Recent studies have shown a dramatic increase in the number of intensive care unit (ICU) beds in ... more Recent studies have shown a dramatic increase in the number of intensive care unit (ICU) beds in recent decades. As technologies have become more complex, ICUs continue to grow in size and in specialization. The driving forces behind ICU bed expansion include not only the incorporation of advanced technologies but also other factors such as the increased utilization of ICU beds for patients who previously were not offered ICU care-those who may be terminally ill and those who are not critically ill. This expansion of ICU care in the United States sets it apart from other industrialized nations with comparably fewer ICU beds in relation to other hospital beds. The consequences of this expansion are now being felt in the form of unused beds, workforce shortages, and overuse of ICUs for patients who previously were not cared for in ICUs. ICUs are also now commonly used in the care of dying patients. In coming decades it is likely that changes will need to take place to forestall exorbi...

Critical care medicine, Jan 24, 2015

Clinical protocols may decrease unnecessary variation in care and improve compliance with desirab... more Clinical protocols may decrease unnecessary variation in care and improve compliance with desirable therapies. We evaluated whether highly protocolized ICUs have superior patient outcomes compared with less highly protocolized ICUs. Observational study in which participating ICUs completed a general assessment and enrolled new patients 1 day each week. A total of 6,179 critically ill patients. Fifty-nine ICUs in the United States Critical Illness and Injury Trials Group Critical Illness Outcomes Study. None. The primary exposure was the number of ICU protocols; the primary outcome was hospital mortality. A total of 5,809 participants were followed prospectively, and 5,454 patients in 57 ICUs had complete outcome data. The median number of protocols per ICU was 19 (interquartile range, 15-21.5). In single-variable analyses, there were no differences in ICU and hospital mortality, length of stay, use of mechanical ventilation, vasopressors, or continuous sedation among individuals in ...

The Laryngoscope, 2005

To investigate a correlation between neck length and the incidence of complications after both pe... more To investigate a correlation between neck length and the incidence of complications after both percutaneous and surgical tracheotomy (ST) and to compare the relative safety of the two procedures at our institution. Prospective, randomized study of patients undergoing tracheotomy at a tertiary care center. Forty-three patients evaluated for tracheotomy at our institution between the years 2003 and 2004 were enrolled in the study and were randomly assigned to receive either an ST or a percutaneous dilatational tracheotomy (PDT). All patients underwent standardized measurement of the cricosternal distance (CSD) in the neutral and extended positions before the procedure. Demographic and procedural variables were recorded, and the occurrence of postoperative complications was followed for 1 week. PDT was performed in 29 patients and ST in 14 patients. The mean CSD of 2.7 cm increased to 3.7 cm after extension with a shoulder roll. PDT required less time (mean 8 vs. 23 minutes) and resulted in less blood loss compared with ST. A trend toward a higher incidence of complications with PDT (40%) compared with ST (7%) and in the first half of our series (learning curve) was noted. This, however, did not reach statistical significance. There was no correlation between the incidence of complications and neck length as determined by the CSD in either group of patients. We failed to demonstrate a correlation between CSD and tracheotomy related complications. Patients with short necks may be at no higher risk during either a PDT or ST. Experience, awareness of complications, and a dedicated team approach are necessary for the safe performance of PDT.

Journal of Emergency Nursing, 2012

Introduction: Despite evidence to support efficacy of early goal-directed therapy for resuscitati... more Introduction: Despite evidence to support efficacy of early goal-directed therapy for resuscitation of patients with severe sepsis and septic shock in the emergency department, implementation remains incomplete. To identify and address specific barriers at our institution and maximize benefits of a planned sepsis treatment initiative, a baseline assessment of knowledge, attitudes, and behaviors regarding detection and treatment of severe sepsis was performed. Methods: An online survey was offered to nurses and physicians in the emergency department of a major urban academic medical center. The questionnaire was designed to assess (1) baseline knowledge and self-reported confidence in identification of systemic inflammatory response syndrome and sepsis; (2) current practices in treatment; (3) difficulties encountered in managing sepsis cases; (4) perceived barriers to implementation of a clinical pathway based on early quantitative resuscitation goals; and (5) to elicit suggestions for improvement of sepsis treatment within the department. Results: Respondents (n = 101) identified barriers to a quantitative resuscitation protocol for sepsis. These barriers included the inability to perform central venous pressure/central venous oxygen saturation monitoring, limited physical space in the emergency department, and lack of sufficient nursing staff. Among nurses, the greatest perceived contributor to delays in treatment was a delay in diagnosis by physicians; among physicians, a delay in availability of ICU beds and nursing delays were the greatest barriers. Despite these issues, respondents indicated that a written protocol would be helpful to them. Discussion: Knowledge gaps and procedural hurdles identified by the survey will inform both educational and process components of an initiative to improve sepsis care in the emergency department.

Infection Control & Hospital Epidemiology, 2005

Objective:To evaluate the relationship betweenStaphylococcus aureusnasal and tracheal colonizatio... more Objective:To evaluate the relationship betweenStaphylococcus aureusnasal and tracheal colonization and infection in medical intensive care unit (MICU) patients. The primary outcome was the incidence ofS. aureusinfection in colonized versus non-colonized patients.Design:Prospective, observational cohort study. Patients admitted to the MICU during the study period were screened forS. aureusnasal and tracheal colonization by culture and a PCR assay twice weekly. Demographic, clinical, and microbiologic data were collected in the MICU and for 30 days after discharge. PFGE and antibiotic susceptibility testing were performed on allS. aureusnasal, tracheal, and clinical isolates.Results:Twenty-three percent of patients (47 of 208) were nasally colonized withS. aureus. Twenty-four percent of these patients developedS. aureusinfections versus 2% of noncolonized patients (P< .01). Nine of 11 patients with both nasal colonization and infection were infected by their colonizing strain. Two ...

Resuscitation, 2003

Cardiopulmonary resuscitation (CPR), as described in 1960, remains the cornerstone of therapy for... more Cardiopulmonary resuscitation (CPR), as described in 1960, remains the cornerstone of therapy for cardiopulmonary arrest. Recent case reports have described CPR in the prone position. We hypothesized rhythmic back pressure on a patient in the prone position with sternal counter-pressure (termed reverse CPR here) would increase intra-thoracic pressure and in turn systolic blood pressure (SBP) during cardiac arrest versus standard CPR. Six patients from Columbia Presbyterian Medical Center&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s Cardiac and Medical Intensive Care Units (CICU and MICU) were enrolled. Eligible patients had suffered circulatory arrest and failed standard CPR for at least 30 min. After enrollment the patients received 15 additional min of standard CPR and then reverse CPR for 15 min. The study&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s primary endpoint, mean SBP, significantly improved from 48 mmHg during standard CPR to 72 mmHg during reverse CPR (mean improvement=23+/-14 mmHg). Mean calculated mean arterial pressure (MAP) was also improved significantly from 32 mmHg during standard CPR to 46 mmHg during reverse CPR (mean improvement=14+/-11 mmHg). The mean diastolic blood pressure (DBP) improved from 24 mmHg during standard to 34 mmHg during reverse CPR (mean improvement=10+/-12 mmHg). This difference did not meet statistical significance. No patients had return of spontaneous circulation. Reverse CPR generates higher mean SBP and higher mean MAP during circulatory arrest than standard CPR. These novel findings justify further research into this technique.