Qualitative Study of Emergency Medicine Residents' Perspectives of Trauma Leadership Development.

Background: Trauma team leadership is a core skill for the practice of emergency medicine (EM). In this study our goal was to explore EM residents' perception of their trauma leadership skill development through formal and informal processes and to understand factors that may impact the development and implementation of trauma leadership skills. Methods: Using qualitative semi-structured interviews, we explored the leadership experiences of 10 EM residents ranging from second to fourth postgraduate year. Interviews were conducted between July 26-October 31, 2019 and were audio-recorded, transcribed, and de-identified. We analyzed data using qualitative content analysis. Results: Residents discussed three main themes: 1) sources of leadership development; 2) challenges with simultaneously assuming a dual leader-learner role; and 3) contextual factors that impact their ability to assume the leadership role, including the professional hierarchy in the clinical environment, limitations in the physical environment, and gender bias. Conclusion: This study describes the complex factors and experiences that contribute to the development and implementation of trauma team leadership skills in EM residents. This includes three primary sources of leadership development, the dual role of leader and learner, and various contextual factors. Research is needed to understand how these factors and experiences can be leveraged or mitigated to improve resident leadership training outcomes.

Developing adaptive performance: A conceptual model to guide simulation-based training design.

Objectives: Effective emergency department care requires individuals and teams to adapt to changes in patient condition, team factors, environmental issues, and system-level challenges. Adaptability is often listed as an important skill for emergency medicine physicians; however, conceptual models describing the processes involved in adaptive performance have not been translated for health care settings. Similarly, educators have not described training design strategies that support the development of adaptive performance. Methods: We examined the team science and health care literatures for key concepts in adaptive performance, health care team performance, and diagnostic decision-making. Using expert consensus, we integrated these concepts to develop the team adaptive performance model and to identify training design approaches that support the development of adaptability. Results: We identify nine training principles supported by the team adaptive performance model and the adaptive learning system. Each training principle is accompanied by recommendations and mechanisms for implementation in emergency medicine simulation-based education. Conclusion: Training experiences can be designed to target processes that support adaptive performance.

Does team leader gender matter? A Bayesian reconciliation of leadership and patient care during trauma resuscitations.

OBJECTIVE: Team leadership facilitates teamwork and is important to patient care. It is unknown whether physician gender-based differences in team leadership exist. The objective of this study was to assess and compare team leadership and patient care in trauma resuscitations led by male and female physicians. METHODS: We performed a secondary analysis of data from a larger randomized controlled trial using video recordings of emergency department trauma resuscitations at a Level 1 trauma center from April 2016 to December 2017. Subjects included emergency medicine and surgery residents functioning as trauma team leaders. Eligible resuscitations included adult patients meeting institutional trauma activation criteria. Two video-recorded observations for each participant were coded for team leadership quality and patient care by 2 sets of raters. Raters were balanced with regard to gender and were blinded to study hypotheses. We used Bayesian regression to determine whether our data supported gender-based advantages in team leadership. RESULTS: A total of 60 participants and 120 video recorded observations were included. The modal relationship between gender and team leadership (ß = 0.94, 95% highest density interval [HDI], -.68 to 2.52) and gender and patient care (ß = 2.42, 95% HDI, -2.03 to 6.78) revealed a weak positive effect for female leaders on both outcomes. Gender-based advantages to team leadership and clinical care were not conclusively supported or refuted, with the exception of rejecting a strong male advantage to team leadership. CONCLUSIONS: We prospectively measured team leadership and clinical care during patient care. Our findings do not support differences in trauma resuscitation team leadership or clinical care based on the gender of the team leader.

Predicting 30-day return hospital admissions in patients with COVID-19 discharged from the emergency department: A national retrospective cohort study.

OBJECTIVES: Identification of patients with coronavirus disease 2019 (COVID-19) at risk for deterioration after discharge from the emergency department (ED) remains a clinical challenge. Our objective was to develop a prediction model that identifies patients with COVID-19 at risk for return and hospital admission within 30 days of ED discharge. METHODS: We performed a retrospective cohort study of discharged adult ED patients (n = 7529) with SARS-CoV-2 infection from 116 unique hospitals contributing to the National Registry of Suspected COVID-19 in Emergency Care. The primary outcome was return hospital admission within 30 days. Models were developed using classification and regression tree (CART), gradient boosted machine (GBM), random forest (RF), and least absolute shrinkage and selection (LASSO) approaches. RESULTS: Among patients with COVID-19 discharged from the ED on their index encounter, 571 (7.6%) returned for hospital admission within 30 days. The machine-learning (ML) models (GBM, RF, and LASSO) performed similarly. The RF model yielded a test area under the receiver operating characteristic curve of 0.74 (95% confidence interval [CI], 0.71-0.78), with a sensitivity of 0.46 (95% CI, 0.39-0.54) and a specificity of 0.84 (95% CI, 0.82-0.85). Predictive variables, including lowest oxygen saturation, temperature, or history of hypertension, diabetes, hyperlipidemia, or obesity, were common to all ML models. CONCLUSIONS: A predictive model identifying adult ED patients with COVID-19 at risk for return for return hospital admission within 30 days is feasible. Ensemble/boot-strapped classification methods (eg, GBM, RF, and LASSO) outperform the single-tree CART method. Future efforts may focus on the application of ML models in the hospital setting to optimize the allocation of follow-up resources.

An Event-based Approach to Measurement: Facilitating Observational Measurement in Highly Variable Clinical Settings.

BACKGROUND: Translational research in medical education requires the ability to rigorously measure learner performance in actual clinical settings; however, current measurement systems cannot accommodate the variability inherent in many patient care  environments. This is especially problematic in emergency medicine, where patients represent a wide spectrum of severity for a single clinical presentation. Our objective is to describe and implement EBAM, an event-based approach to measurement that can be applied to actual emergency medicine clinical events. METHODS: We used a four-step event-based approach to create an emergency department trauma resuscitation patient care measure. We applied the measure to a database of 360 actual trauma resuscitations recorded in a Level I trauma center using trained raters. A subset (n = 50) of videos was independently rated in duplicate to determine inter-rater reliability. Descriptive analyses were performed to describe characteristics of resuscitation events and Cohen's kappa was used to calculate reliability. RESULTS: The methodology created a metric containing both universal items that are applied to all trauma resuscitation events and conditional items that only apply in certain situations. For clinical trauma events, injury severity scores ranged from 1 to 75 with a mean (±SD) of 21 (±15) and included both blunt (254/360; 74%) and penetrating (86/360; 25%) traumatic injuries, demonstrating the diverse nature of the clinical encounters. The mean (±SD) Cohen's kappa for patient care items was 0.7 (±0.3). CONCLUSION: We present an event-based approach to performance assessment that may address a major gap in translational education research. Our work centered on assessment of patient care behaviors during trauma resuscitation. More work is needed to evaluate this approach across a diverse array of clinical events.

Barriers and Solutions to Advancing Emergency Medicine Simulation-based Research: A Call to Action.

Simulation technology has successfully improved patient safety and care quality through training and assessment of individuals, teams, and health care systems. Emergency medicine (EM) continues to be a leader and pioneer of simulation, including administration of simulation-based fellowships and training programs. However, EM simulation-based research has been limited by low rates of publication and poor methodologic rigor. The Society for Academic Emergency Medicine (SAEM) Simulation Academy is leading efforts to improve the quality of scholarship generated by the EM simulation community and to foster successful research careers for future generations of EM simulationists. Through a needs assessment survey of our membership and a year-long consensus-based approach, we identified two main clusters of barriers to simulation-based research: lack of protected time and dedicated resources and limited training and mentorship. As a result, we generated four position statements with implications for education, training, and research in EM simulation and as a call to action for the academic EM community. Recommendations include expansion of funding opportunities for simulation-based research, creation of multi-institutional simulation collaboratives, and development of mentorship and training pathways that promote rigor in design and methodology within EM simulation scholarship.

Simulation-Based Team Leadership Training Improves Team Leadership During Actual Trauma Resuscitations: A Randomized Controlled Trial.

OBJECTIVES: Trauma resuscitations are complex critical care events that present patient safety-related risk. Simulation-based leadership training is thought to improve trauma care; however, there is no robust evidence supporting the impact of leadership training on clinical performance. The objective of this study was to assess the clinical impact of simulation-based leadership training on team leadership and patient care during actual trauma resuscitations. DESIGN: Randomized controlled trial. SETTING: Harborview Medical Center (level 1 trauma center). SUBJECTS: Seventy-nine second- and third-year residents were randomized and 360 resuscitations were analyzed. INTERVENTIONS: Subjects were randomized to a 4-hour simulation-based leadership training (intervention) or standard orientation (control) condition. MEASUREMENTS AND MAIN RESULTS: Participant-led actual trauma resuscitations were video recorded and coded for leadership behaviors and patient care. We used random coefficient modeling to account for the nesting effect of multiple observations within residents and to test for post-training group differences in leadership behaviors while controlling for pre-training behaviors, Injury Severity Score, postgraduate training year, and days since training occurred. Sixty participants completed the study. There was a significant difference in post-training leadership behaviors between the intervention and control conditions (b1 = 4.06, t (55) = 6.11, p < 0.001; intervention M = 11.29, SE = 0.66, 95% CI, 9.99-12.59 vs control M = 7.23, SE = 0.46, 95% CI, 6.33-8.13, d = 0.92). Although patient care was similar between conditions (b = 2.00, t (55) = 0.99, p = 0.325; predicted means intervention M = 62.38, SE = 2.01, 95% CI, 58.43-66.33 vs control M = 60.38, SE = 1.37, 95% CI, 57.69-63.07, d = 0.15), a test of the mediation effect between training and patient care suggests leadership behaviors mediate an effect of training on patient care with a significant indirect effect (b = 3.44, 95% CI, 1.43-5.80). Across all trauma resuscitations leadership was significantly related to patient care (b1 = 0.61, SE = 0.15, t (273) = 3.64, p < 0.001). CONCLUSIONS: Leadership training resulted in the transfer of complex skills to the clinical environment and may have an indirect effect on patient care through better team leadership.

Identification of processes that mediate the impact of workplace violence on emergency department healthcare workers in the USA: results from a qualitative study.

OBJECTIVES: Violence towards emergency department healthcare workers is pervasive and directly linked to provider wellness, productivity and job satisfaction. This qualitative study aimed to identify the cognitive and behavioural processes impacted by workplace violence to further understand why workplace violence has a variable impact on individual healthcare workers. DESIGN: Qualitative interview study using a phenomenological approach to initial content analysis and secondary thematic analysis. SETTING: Three different emergency departments. PARTICIPANTS: We recruited 23 emergency department healthcare workers who experienced a workplace violence event to participate in an interview conducted within 24 hours of the event. Participants included nurses (n=9; 39%), medical assistants (n=5; 22%), security guards (n=5; 22%), attending physicians (n=2; 9%), advanced practitioners (n=1; 4%) and social workers (n=1; 4%). RESULTS: Five themes emerged from the data. The first two supported existing reports that workplace violence in healthcare is pervasive and contributes to burn-out in healthcare. Three novel themes emerged from the data related to the objectives of this study: (1) variability in primary cognitive appraisals of workplace violence, (2) variability in secondary cognitive appraisals of workplace violence and (3) reported use of both avoidant and approach coping mechanisms. CONCLUSION: Healthcare workers identified workplace violence as pervasive. Variability in reported cognitive appraisal and coping strategies may partially explain why workplace violence negatively impacts some healthcare workers more than others. These cognitive and behavioural processes could serve as targets for decreasing the negative effect of workplace violence, thereby improving healthcare worker well-being. Further research is needed to develop interventions that mitigate the negative impact of workplace violence.

Targeted Simulation-based Leadership Training for Trauma Team Leaders.

INTRODUCTION: Effective team leadership is linked to better teamwork, which in turn is believed to improve patient care. Simulation-based training provides a mechanism to develop effective leadership behaviors. Traditionally, healthcare curricula have included leadership as a small component of broader teamwork training, with very few examples of leadership-focused curricula. The objective of this work is to describe a novel simulation-based team leadership curriculum that easily adapts to individual learners. METHODS: We created a simulation-based team leadership training for trauma team leaders in graduate medical education. Participants included second- and third-year emergency medicine and surgery residents. Training consisted of a single, four-hour session and included facilitated discussion of trauma leadership skills, a brief didactic session integrating leadership behaviors into Advanced Trauma Life Support®, and a series of simulations and debriefing sessions. The simulations contained adaptable components that facilitated individualized learning while delivering set curricular content. A survey evaluation was administered 7-24 months following the training to assess self-reported implementation of trained material. RESULTS: A total of 36 residents participated in the training and 23 (64%) responded to the survey. The majority of respondents (n = 22, 96%) felt the training was a valuable component of their residency education and all respondents reported ongoing use of at least one behavior learned during the training. The most commonly cited skills for ongoing use included the pre-arrival brief (n = 21, 91%) and prioritization (n = 21, 91%). CONCLUSION: We delivered a leadership-focused, simulation-based training that 1) adapted to learners' individual needs, and 2) was perceived to impact practice up to 24 months post-training. More work is needed to understand the impact of this training on learner knowledge and behavior, as well as patient outcomes.

Development and Empirical Testing of a Novel Team Leadership Assessment Measure: A Pilot Study Using Simulated and Live Patient Encounters.

BACKGROUND: Team leadership is critical to health care resuscitation team performance. There has been increased focus on competency in team leadership behaviors; however, there is still variability in how team leadership is assessed within emergency medicine. The objective of this study was to develop and pilot a novel team leadership assessment measure for emergency medicine resuscitation teams. METHODS: Team leadership dimensions and associated behaviors were identified through a systematic literature review and expert consensus. Included behaviors were used to create behaviorally anchored rating scales, which were then revised based on subject matter expert ratings. Four raters from three different academic institutions observed 30 video-recorded resuscitations (20 simulated and 10 actual patient care resuscitations). Mean leadership scores were calculated. Intraclass coefficients (ICCs) were calculated for each item and for overall leadership scores. Leader scores for the simulation-based scenarios were compared to external variables including level of training, team process, clinical performance, and team situational awareness. The study was conducted from July 2017 through June 2018. RESULTS: Leadership scores ranged from 2.23 to 4.30 (mean [±SD] = 3.18 [±0.50]). The ICC for the overall score was 0.79 for all observations, 0.87 for simulation-based observations, and 0.24 for the patient care observations. Team leadership scores on simulation-based observations did not correlate with available external variables. CONCLUSIONS: We developed a novel team leadership assessment measure for emergency medicine resuscitation teams with supporting validity evidence, including content validity and response process. The measure demonstrated acceptable inter-rater reliability when applied to simulation-based medical resuscitations; however, this did not translate to trauma resuscitations in the actual patient care setting.

Changing Systems Through Effective Teams: A Role for Simulation.

Teams are the building blocks of the healthcare system, with growing evidence linking the quality of healthcare to team effectiveness, and team effectiveness to team training. Simulation has been identified as an effective modality for team training and assessment. Despite this, there are gaps in methodology, measurement, and implementation that prevent maximizing the impact of simulation modalities on team performance. As part of the 2017 Academic Emergency Medicine Consensus Conference "Catalyzing System Change Through Health Care Simulation: Systems, Competency, and Outcomes," we explored the impact of simulation on various aspects of team effectiveness. The consensus process included an extensive literature review, group discussions, and the conference "workshop" involving emergency medicine physicians, medical educators, and team science experts. The objectives of this work were to: 1) explore the antecedents and processes that support team effectiveness, 2) summarize the current role of simulation in developing and understanding team effectiveness, and 3) identify research targets to further improve team-based training and assessment, with the ultimate goal of improving healthcare systems.

A Simulation-based Approach to Measuring Team Situational Awareness in Emergency Medicine: A Multicenter, Observational Study.

OBJECTIVES: Team situational awareness (TSA) is critical for effective teamwork and supports dynamic decision making in unpredictable, time-pressured situations. Simulation provides a platform for developing and assessing TSA, but these efforts are limited by suboptimal measurement approaches. The objective of this study was to develop and evaluate a novel approach to TSA measurement in interprofessional emergency medicine (EM) teams. METHODS: We performed a multicenter, prospective, simulation-based observational study to evaluate an approach to TSA measurement. Interprofessional emergency medical teams, consisting of EM resident physicians, nurses, and medical students, were recruited from the University of Washington (Seattle, WA) and Wayne State University (Detroit, MI). Each team completed a simulated emergency resuscitation scenario. Immediately following the simulation, team members completed a TSA measure, a team perception of shared understanding measure, and a team leader effectiveness measure. Subject matter expert reviews and pilot testing of the TSA measure provided evidence of content and response process validity. Simulations were recorded and independently coded for team performance using a previously validated measure. The relationships between the TSA measure and other variables (team clinical performance, team perception of shared understanding, team leader effectiveness, and team experience) were explored. The TSA agreement metric was indexed by averaging the pairwise agreement for each dyad on a team and then averaging across dyads to yield agreement at the team level. For the team perception of shared understanding and team leadership effectiveness measures, individual team member scores were aggregated within a team to create a single team score. We computed descriptive statistics for all outcomes. We calculated Pearson's product-moment correlations to determine bivariate correlations between outcome variables with two-tailed significance testing (p < 0.05). RESULTS: A total of 123 participants were recruited and formed three-person teams (n = 41 teams). All teams completed the assessment scenario and postsimulation measures. TSA agreement ranged from 0.19 to 0.9 and had a mean (±SD) of 0.61 (±0.17). TSA correlated with team clinical performance (p < 0.05) but did not correlate with team perception of shared understanding, team leader effectiveness, or team experience. CONCLUSIONS: Team situational awareness supports adaptive teams and is critical for high reliability organizations such as healthcare systems. Simulation can provide a platform for research aimed at understanding and measuring TSA. This study provides a feasible method for simulation-based assessment of TSA in interdisciplinary teams that addresses prior measure limitations and is appropriate for use in highly dynamic, uncertain situations commonly encountered in emergency department systems. Future research is needed to understand the development of and interactions between individual-, team-, and system (distributed)-level cognitive processes.

Randomised controlled trial to assess the effect of a Just-in-Time training on procedural performance: a proof-of-concept study to address procedural skill decay.

BACKGROUND: A subset of high-risk procedures present significant safety threats due to their (1) infrequent occurrence, (2) execution under time constraints and (3) immediate necessity for patient survival. A Just-in-Time (JIT) intervention could provide real-time bedside guidance to improve high-risk procedural performance and address procedural deficits associated with skill decay. OBJECTIVE: To evaluate the impact of a novel JIT intervention on transvenous pacemaker (TVP) placement during a simulated patient event. METHODS: This was a prospective, randomised controlled study to determine the effect of a JIT intervention on performance of TVP placement. Subjects included board-certified emergency medicine physicians from two hospitals. The JIT intervention consisted of a portable, bedside computer-based procedural adjunct. The primary outcome was performance during a simulated patient encounter requiring TVP placement, as assessed by trained raters using a technical skills checklist. Secondary outcomes included global performance ratings, time to TVP placement, number of critical omissions and System Usability Scale scores (intervention only). RESULTS: Groups were similar at baseline across all outcomes. Compared with the control group, the intervention group demonstrated statistically significant improvement in the technical checklist score (11.45 vs 23.44, p<0.001, Cohen's d effect size 4.64), the global rating scale (2.27 vs 4.54, p<0.001, Cohen's d effect size 3.76), and a statistically significant reduction in critical omissions (2.23 vs 0.68, p<0.001, Cohen's d effect size -1.86). The difference in time to procedural completion was not statistically significant between conditions (11.15 min vs 12.80 min, p=0.12, Cohen's d effect size 0.65). System Usability Scale scores demonstrated excellent usability. CONCLUSION: A JIT intervention improved procedure perfromance, suggesting a role for JIT interventions in rarely performed procedures.

Developing Team Cognition: A Role for Simulation.

STATEMENT: Simulation has had a major impact in the advancement of healthcare team training and assessment. To date, most simulation-based training and assessments focus on the teamwork behaviors that impact team performance, often ignoring critical cognitive, motivational, and affective team processes. Evidence from team science research demonstrates a strong relationship between team cognition and team performance and suggests a role for simulation in the development of this team-level construct. In this article, we synthesize research from the broader team science literature to provide foundational knowledge regarding team cognition and highlight best practices for using simulation to target team cognition.

Assessing Team Leadership in Emergency Medicine: The Milestones and Beyond.

BACKGROUND: Team leadership is a critical skill for emergency medicine physicians that directly affects team performance and the quality of patient care. There exists a robust body of team science research supporting team leadership conceptual models and behavioral skill sets. However, to date, this work has not been widely incorporated into health care team leadership education. OBJECTIVE: This narrative review has 3 aims: (1) to synthesize the team science literature and to translate important concepts and models to health care team leadership; (2) to describe how team leadership is currently represented in the health care literature and in the Accreditation Council for Graduate Medical Education Milestones for emergency medicine; and (3) to propose a novel, evidence-based framework for the assessment of team leadership in emergency medicine. METHODS: We conducted a narrative review of the team science and health care literature. We summarized our findings and identified a list of team leadership behaviors that were then used to create a framework for team leadership assessment. RESULTS: Current health care team leadership measurement tools do not incorporate evidence-based models of leadership concepts from other established domains. The emergency medicine milestones include several team leadership behaviors as part of a larger resident evaluation program. However, they do not offer a comprehensive or cohesive representation of the team leadership construct. CONCLUSIONS: Despite the importance of team leadership to patient care, there is no standardized approach to team leadership assessment in emergency medicine. Based on the results of our review, we propose a novel team leadership assessment framework that is supported by the team science literature.

A Systematic Review of Tools Used to Assess Team Leadership in Health Care Action Teams.

PURPOSE: To summarize the characteristics of tools used to assess leadership in health care action (HCA) teams. HCA teams are interdisciplinary teams performing complex, critical tasks under high-pressure conditions. METHOD: The authors conducted a systematic review of the PubMed/MEDLINE, CINAHL, ERIC, EMBASE, PsycINFO, and Web of Science databases, key journals, and review articles published through March 2012 for English-language articles that applied leadership assessment tools to HCA teams in all specialties. Pairs of reviewers assessed identified articles for inclusion and exclusion criteria and abstracted data on study characteristics, tool characteristics, and validity evidence. RESULTS: Of the 9,913 abstracts screened, 83 studies were included. They described 61 team leadership assessment tools. Forty-nine tools (80%) provided behaviors, skills, or characteristics to define leadership. Forty-four tools (72%) assessed leadership as one component of a larger assessment, 13 tools (21%) identified leadership as the primary focus of the assessment, and 4 (7%) assessed leadership style. Fifty-three studies (64%) assessed leadership at the team level; 29 (35%) did so at the individual level. Assessments of simulated (n = 55) and live (n = 30) patient care events were performed. Validity evidence included content validity (n = 75), internal structure (n = 61), relationship to other variables (n = 44), and response process (n = 15). CONCLUSIONS: Leadership assessment tools applied to HCA teams are heterogeneous in content and application. Comparisons between tools are limited by study variability. A systematic approach to team leadership tool development, evaluation, and implementation will strengthen understanding of this important competency.

Leadership training in health care action teams: a systematic review.

PURPOSE: To identify and describe the design, implementation, and evidence of effectiveness of leadership training interventions for health care action (HCA) teams, defined as interdisciplinary teams whose members coordinate their actions in time-pressured, unstable situations. METHOD: The authors conducted a systematic search of the PubMed/MEDLINE, CINAHL, ERIC, EMBASE, PsycINFO, and Web of Science databases, key journals, and review articles published through March 2012. They identified peer-reviewed English-language articles describing leadership training interventions targeting HCA teams, at all levels of training and across all health care professions. Reviewers, working in duplicate, abstracted training characteristics and outcome data. Methodological quality was evaluated using the Medical Education Research Study Quality Instrument (MERSQI). RESULTS: Of the 52 included studies, 5 (10%) focused primarily on leadership training, whereas the remainder included leadership training as part of a larger teamwork curriculum. Few studies reported using a team leadership model (2; 4%) or a theoretical framework (9; 17%) to support their curricular design. Only 15 studies (29%) specified the leadership behaviors targeted by training. Forty-five studies (87%) reported an assessment component; of those, 31 (69%) provided objective outcome measures including assessment of knowledge or skills (21; 47%), behavior change (8; 18%), and patient- or system-level metrics (8; 18%). The mean MERSQI score was 11.4 (SD 2.9). CONCLUSIONS: Leadership training targeting HCA teams has become more prevalent. Determining best practices in leadership training is confounded by variability in leadership definitions, absence of supporting frameworks, and a paucity of robust assessments.

Two putative acetyltransferases, san and deco, are required for establishing sister chromatid cohesion in Drosophila.

BACKGROUND: Sister chromatid cohesion is needed for proper alignment and segregation of chromosomes during cell division. Chromatids are linked by the multiprotein cohesin complex, which binds to DNA during G(1) and then establishes cohesion during S phase DNA replication. However, many aspects of the mechanisms that establish and maintain cohesion during mitosis remain unclear. RESULTS: We found that mutations in two evolutionarily conserved Drosophila genes, san (separation anxiety) and deco (Drosophila eco1), disrupt centromeric sister chromatid cohesion very early in division. This failure of sister chromatid cohesion does not require separase and is correlated with a failure of the cohesin component Scc1 to accumulate in centromeric regions. It thus appears that these mutations interfere with the establishment of centromeric sister chromatid cohesion. Secondary consequences of these mutations include activation of the spindle checkpoint, causing metaphase delay or arrest. Some cells eventually escape the block but incur many errors in anaphase chromosome segregation. Both san and deco are predicted to encode acetyltransferases, which transfer acetyl groups either to internal lysine residues or to the N terminus of other proteins. The San protein is itself acetylated, and it associates with the Nat1 and Ard1 subunits of the NatA acetyltransferase. CONCLUSIONS: At least two diverse acetyltransferases play vital roles in regulating sister chromatid cohesion during Drosophila mitosis.