Clinical Focus

  • Anesthesia
  • Pediatric anesthesia

Academic Appointments

Professional Education

  • Medical Education: Thomas Jefferson University Office of the Registrar (2006) PA
  • Internship: Lankenau Medical Center PA
  • Residency: Dartmouth-Hitchcock Medical Center NH
  • Fellowship: University of Chicago GME Office IL
  • Board Certification: American Board of Anesthesiology, Anesthesia (2011)
  • Board Certification: American Board of Anesthesiology, Pediatric Anesthesia (2014)
  • M.S., Stanford University, Masters of Health Policy (2019)


All Publications

  • Preventing Intravenous Injection Port Contamination ANESTHESIA AND ANALGESIA Muffly, M. K., Loftus, R. W., Yeager, M. P. 2020; 131 (3): E160?E161
  • Speeding the Detection of Vessel Cannulation: An In-Vitro Stimulation Study ANESTHESIA AND ANALGESIA Muffly, M. K., Ku, A., Drover, D. R., Rodriguez, S., Caruso, T. J., Ku, A., Tsui, B. H. 2020; 130 (1): 159?64
  • Practice Characteristics of Board-certified Pediatric Anesthesiologists in the US: A Nationwide Survey CUREUS Muffly, M., Scheinker, D., Muffly, T., Singleton, M., Agarwal, R., Honkanen, A. 2019; 11 (9)
  • Operative Versus Nonoperative Management of Appendicitis: A Long-Term Cost Effectiveness Analysis. MDM policy & practice Sceats, L. A., Ku, S., Coughran, A., Barnes, B., Grimm, E., Muffly, M., Spain, D. A., Kin, C., Owens, D. K., Goldhaber-Fiebert, J. D. 2019; 4 (2): 2381468319866448


    Background. Recent clinical trials suggest that nonoperative management (NOM) of patients with acute, uncomplicated appendicitis is an acceptable alternative to surgery. However, limited data exist comparing the long-term cost-effectiveness of nonoperative treatment strategies. Design. We constructed a Markov model comparing the cost-effectiveness of three treatment strategies for uncomplicated appendicitis: 1) laparoscopic appendectomy, 2) inpatient NOM, and 3) outpatient NOM. The model assessed lifetime costs and outcomes from a third-party payer perspective. The preferred strategy was the one yielding the greatest utility without exceeding a $50,000 willingness-to-pay threshold. Results. Outpatient NOM cost $233,700 over a lifetime; laparoscopic appendectomy cost $2500 more while inpatient NOM cost $7300 more. Outpatient NOM generated 24.9270 quality-adjusted life-years (QALYs), while laparoscopic appendectomy and inpatient NOM yielded 0.0709 and 0.0005 additional QALYs, respectively. Laparoscopic appendectomy was cost-effective compared with outpatient NOM (incremental cost-effectiveness ratio $32,300 per QALY gained); inpatient NOM was dominated by laparoscopic appendectomy. In one-way sensitivity analyses, the preferred strategy changed when varying perioperative mortality, probability of appendiceal malignancy or recurrent appendicitis after NOM, probability of a complicated recurrence, and appendectomy cost. A two-way sensitivity analysis showed that the rates of NOM failure and appendicitis recurrence described in randomized trials exceeded the values required for NOM to be preferred. Limitations. There are limited NOM data to generate long-term model probabilities. Health state utilities were often drawn from single studies and may significantly influence model outcomes. Conclusion. Laparoscopic appendectomy is a cost-effective treatment for acute uncomplicated appendicitis over a lifetime time horizon. Inpatient NOM was never the preferred strategy in the scenarios considered here. These results emphasize the importance of considering long-term costs and outcomes when evaluating NOM.

    View details for DOI 10.1177/2381468319866448

    View details for PubMedID 31453362

  • The Pediatric Anesthesiology Workforce: Projecting Supply and Trends 2015-2035 ANESTHESIA AND ANALGESIA Muffly, M. K., Singleton, M., Agarwal, R., Scheinker, D., Miller, D., Muffly, T. M., Honkanen, A. 2018; 126 (2): 568?78


    A workforce analysis was conducted to predict whether the projected future supply of pediatric anesthesiologists is balanced with the requirements of the inpatient pediatric population. The specific aims of our analysis were to (1) project the number of pediatric anesthesiologists in the future workforce; (2) project pediatric anesthesiologist-to-pediatric population ratios (0-17 years); (3) project the mean number of inpatient pediatric procedures per pediatric anesthesiologist; and (4) evaluate the effect of alternative projections of individual variables on the model projections through 2035.The future number of pediatric anesthesiologists is determined by the current supply, additions to the workforce, and departures from the workforce. We previously compiled a database of US pediatric anesthesiologists in the base year of 2015. The historical linear growth rate for pediatric anesthesiology fellowship positions was determined using the Accreditation Council for Graduate Medical Education Data Resource Books from 2002 to 2016. The future number of pediatric anesthesiologists in the workforce was projected given growth of pediatric anesthesiology fellowship positions at the historical linear growth rate, modeling that 75% of graduating fellows remain in the pediatric anesthesiology workforce, and anesthesiologists retire at the current mean retirement age of 64 years old. The baseline model projections were accompanied by age- and gender-adjusted anesthesiologist supply, and sensitivity analyses of potential variations in fellowship position growth, retirement, pediatric population, inpatient surgery, and market share to evaluate the effect of each model variable on the baseline model. The projected ratio of pediatric anesthesiologists to pediatric population was determined using the 2012 US Census pediatric population projections. The projected number of inpatient pediatric procedures per pediatric anesthesiologist was determined using the Kids' Inpatient Database historical data to project the future number of inpatient procedures (including out of operating room procedures).In 2015, there were 5.4 pediatric anesthesiologists per 100,000 pediatric population and a mean (±standard deviation [SD]) of 262 ±8 inpatient procedures per pediatric anesthesiologist. If historical trends continue, there will be an estimated 7.4 pediatric anesthesiologists per 100,000 pediatric population and a mean (±SD) 193 ±6 inpatient procedures per pediatric anesthesiologist in 2035. If pediatric anesthesiology fellowship positions plateau at 2015 levels, there will be an estimated 5.7 pediatric anesthesiologists per 100,000 pediatric population and a mean (±SD) 248 ±7 inpatient procedures per pediatric anesthesiologist in 2035.If historical trends continue, the growth in pediatric anesthesiologist supply may exceed the growth in both the pediatric population and inpatient procedures in the 20-year period from 2015 to 2035.

    View details for PubMedID 29116973

  • Small-Volume Injections: Evaluation of Volume Administration Deviation From Intended Injection Volumes. Anesthesia and analgesia Muffly, M. K., Chen, M. I., Claure, R. E., Drover, D. R., Efron, B., Fitch, W. L., Hammer, G. B. 2017


    In the perioperative period, anesthesiologists and postanesthesia care unit (PACU) nurses routinely prepare and administer small-volume IV injections, yet the accuracy of delivered medication volumes in this setting has not been described. In this ex vivo study, we sought to characterize the degree to which small-volume injections (?0.5 mL) deviated from the intended injection volumes among a group of pediatric anesthesiologists and pediatric postanesthesia care unit (PACU) nurses. We hypothesized that as the intended injection volumes decreased, the deviation from those intended injection volumes would increase.Ten attending pediatric anesthesiologists and 10 pediatric PACU nurses each performed a series of 10 injections into a simulated patient IV setup. Practitioners used separate 1-mL tuberculin syringes with removable 18-gauge needles (Becton-Dickinson & Company, Franklin Lakes, NJ) to aspirate 5 different volumes (0.025 mL, 0.05 mL, 0.1 mL, 0.25 mL, and 0.5 mL) of 0.25 mM Lucifer Yellow (LY) fluorescent dye constituted in saline (Sigma Aldrich, St. Louis, MO) from a rubber-stoppered vial. Each participant then injected the specified volume of LY fluorescent dye via a 3-way stopcock into IV tubing with free-flowing 0.9% sodium chloride (10 mL/min). The injected volume of LY fluorescent dye and 0.9% sodium chloride then drained into a collection vial for laboratory analysis. Microplate fluorescence wavelength detection (Infinite M1000; Tecan, Mannedorf, Switzerland) was used to measure the fluorescence of the collected fluid. Administered injection volumes were calculated based on the fluorescence of the collected fluid using a calibration curve of known LY volumes and associated fluorescence. To determine whether deviation of the administered volumes from the intended injection volumes increased at lower injection volumes, we compared the proportional injection volume error (loge [administered volume/intended volume]) for each of the 5 injection volumes using a linear regression model. Analysis of variance was used to determine whether the absolute log proportional error differed by the intended injection volume. Interindividual and intraindividual deviation from the intended injection volume was also characterized.As the intended injection volumes decreased, the absolute log proportional injection volume error increased (analysis of variance, P < .0018). The exploratory analysis revealed no significant difference in the standard deviations of the log proportional errors for injection volumes between physicians and pediatric PACU nurses; however, the difference in absolute bias was significantly higher for nurses with a 2-sided significance of P = .03.Clinically significant dose variation occurs when injecting volumes ?0.5 mL. Administering small volumes of medications may result in unintended medication administration errors.

    View details for DOI 10.1213/ANE.0000000000001976

    View details for PubMedID 28338490

  • In Response. Anesthesia and analgesia Muffly, M., Honkanen, A., Singleton, M. 2017

    View details for DOI 10.1213/ANE.0000000000002037

    View details for PubMedID 28319513

  • Reporting of Perioperative Adverse Events by Pediatric Anesthesiologists at a Tertiary Children's Hospital: Targeted Interventions to Increase the Rate of Reporting. Anesthesia and analgesia Williams, G. D., Muffly, M. K., Mendoza, J. M., Wixson, N., Leong, K., Claure, R. E. 2017


    Incident reporting systems (IRSs) are important patient safety tools for identifying risks and opportunities for improvement. A major IRS limitation is underreporting of incidents. Perioperative anesthesia IRSs have been established at multiple pediatric institutions and a national pediatric anesthesia IRS for perioperative serious adverse events (SAEs) is maintained by Wake Up Safe (WUS), a patient safety organization dedicated to pediatric anesthesia quality improvement. A confidential, electronic, perioperative IRS was instituted at our tertiary children's hospital, which is a WUS member. The primary study aim was to increase the rate of incident reporting by anesthesiologists at our institution through a series of interventions. The secondary aim was to characterize our reporting behavior relative to national practice by referencing SAE data from WUS.Perioperative adverse events reported over a 71-month period (November 2010 to September 2016) were categorized and the monthly reporting rates determined. Effects of 6 interventions targeted to increase the reporting rate were analyzed using control charts. Intervention 5 involved interviewing pediatric anesthesiologists to ascertain incident reporting barriers and motivators. A key driver diagram was developed and used to guide an improvement initiative. Incidents that fulfilled WUS criteria for SAEs were identified and categorized. SAE reporting rates over a 27-month period for 12 WUS member institutions were determined.2689 perioperative adverse events were noted in 1980 of 72,384 anesthetics. Mean monthly adverse event case rate was 273 (95% confidence interval, 250-297) per 10,000 anesthetics. A subgroup involving 54,469 cases had 529 SAEs in 440 anesthetics; a mean monthly SAE case rate of 80 (95% confidence interval, 69-91) per 10,000 anesthetics. Cardiac, respiratory, and airway events predominated. Relative to WUS peer members, our institution is a high-reporting outlier. The rate of incident reporting per 10,000 anesthetics was sustainably increased from 149 ± 35 to 387 ± 73 (mean ± SD) after implementing mandatory IRS data entry and Intervention 5 quality improvement initiative. Barriers to reporting included concern for punitive repercussions, feelings of incompetence, poor education about what constitutes an event, lack of feedback, and the perception that reporting had no value. These were addressed by IRS education, cultivation of a culture of safety where reporting is encouraged, reporter feedback, and better inclusion of anesthesiologists in patient safety work.Electronic mandatory IRS data entry and an initiative to understand and address reporting barriers and motivators were associated with sustained increases in the adverse event reporting rate. These strategies to minimize underreporting enhance IRS value for learning and may be generalizable.

    View details for PubMedID 28678071

  • The Geographic Distribution of Pediatric Anesthesiologists Relative to the U.S. Pediatric Population. Anesthesia and analgesia Muffly, M. K., Medeiros, D., Muffly, T. M., Singleton, M. A., Honkanen, A. 2016: -?


    The geographic relationship between pediatric anesthesiologists and the pediatric population has potentially important clinical and policy implications. In the current study, we describe the geographic distribution of pediatric anesthesiologists relative to the U.S. pediatric population (0-17 years) and a subset of the pediatric population (0-4 years).The percentage of the U.S. pediatric population that lives within different driving distances to the nearest pediatric anesthesiologist (0 to 25 miles, >25 to 50 miles, >50 to 100 miles, >100 to 250 miles, and >250 miles) was determined by creating concentric driving distance service areas surrounding pediatric anesthesiologist practice locations. U.S. Census block groups were used to determine the sum pediatric population in each anesthesiologist driving distance service area. The pediatric anesthesiologist-to-pediatric population ratio was then determined for each of the 306 hospital referral regions (HRRs) in the United States and compared with ratios of other physician groups to the pediatric population. All geographic mapping and analysis was performed using ArcGIS Desktop 10.2.2 mapping software (Redlands, CA).A majority of the pediatric population (71.4%) lives within a 25-mile drive of a pediatric anesthesiologist; however, 10.2 million U.S. children (0-17 years) live greater than 50 miles from the nearest pediatric anesthesiologist. More than 2.7 million children ages 0 to 4 years live greater than 50 miles from the nearest identified pediatric anesthesiologist. The median ratio of pediatric anesthesiologists to 100,000 pediatric population at the HRR level was 2.25 (interquartile range, 0-5.46). Pediatric anesthesiologist geographic distribution relative to the pediatric population by HRR is lower and less uniform than for all anesthesiologists, neonatologists, and pediatricians.A substantial proportion of the U.S. pediatric population lives greater than 50 miles from the nearest pediatric anesthesiologist, and pediatric anesthesiologist-to-pediatric population ratios by HRR vary widely across the United States. These findings are important given that the new guidelines from the American College of Surgeons Children's Surgery Verification? Quality Improvement Program state that pediatric anesthesiologists must care for a subset of pediatric patients. Because of the geographic distribution of pediatric anesthesiologists relative to the pediatric population, access to care by a pediatric anesthesiologist may not be feasible for all children, particularly for those with limited resources or in emergent situations.

    View details for PubMedID 27984248

  • The Current Landscape of US Pediatric Anesthesiologists: Demographic Characteristics and Geographic Distribution ANESTHESIA AND ANALGESIA Muffly, M. K., Muffly, T. M., Weterings, R., Singleton, M., Honkanen, A. 2016; 123 (1): 179-185


    There is no comprehensive database of pediatric anesthesiologists, their demographic characteristics, or geographic location in the United States.We endeavored to create a comprehensive database of pediatric anesthesiologists by merging individuals identified as US pediatric anesthesiologists by the American Board of Anesthesiology, National Provider Identifier registry, database, and the Society for Pediatric Anesthesia membership list as of November 5, 2015. Professorial rank was accessed via the Association of American Medical Colleges and other online sources. Descriptive statistics characterized pediatric anesthesiologists' demographics. Pediatric anesthesiologists' locations at the city and state level were geocoded and mapped with the use of ArcGIS Desktop 10.1 mapping software (Redlands, CA).We identified 4048 pediatric anesthesiologists in the United States, which is approximately 8.8% of the physician anesthesiology workforce (n = 46,000). The median age of pediatric anesthesiologists was 49 years (interquartile range, 40-57 years), and the majority (56.4%) were men. Approximately two-thirds of identified pediatric anesthesiologists were subspecialty board certified in pediatric anesthesiology, and 33% of pediatric anesthesiologists had an identified academic affiliation. There is substantial heterogeneity in the geographic distribution of pediatric anesthesiologists by state and US Census Division with urban clustering.This description of pediatric anesthesiologists' demographic characteristics and geographic distribution fills an important gap in our understanding of pediatric anesthesia systems of care.

    View details for DOI 10.1213/ANE.0000000000001266

    View details for Web of Science ID 000378083300024

    View details for PubMedID 27049856

  • Hand Contamination of Anesthesia Providers Is an Important Risk Factor for Intraoperative Bacterial Transmission ANESTHESIA AND ANALGESIA Loftus, R. W., Muffly, M. K., Brown, J. R., Beach, M. L., Koff, M. D., Corwin, H. L., Surgenor, S. D., Kirkland, K. B., Yeager, M. P. 2011; 112 (1): 98-105


    We have recently shown that intraoperative bacterial transmission to patient IV stopcock sets is associated with increased patient mortality. In this study, we hypothesized that bacterial contamination of anesthesia provider hands before patient contact is a risk factor for direct intraoperative bacterial transmission.Dartmouth-Hitchcock Medical Center is a tertiary care and level 1 trauma center with 400 inpatient beds and 28 operating suites. The first and second operative cases in each of 92 operating rooms were randomly selected for analysis. Eighty-two paired samples were analyzed. Ten pairs of cases were excluded because of broken or missing sampling protocol and lost samples. We identified cases of intraoperative bacterial transmission to the patient IV stopcock set and the anesthesia environment (adjustable pressure-limiting valve and agent dial) in each operating room pair by using a previously validated protocol. We then used biotype analysis to compare these transmitted organisms to those organisms isolated from the hands of anesthesia providers obtained before the start of each case. Provider-origin transmission was defined as potential pathogens isolated in the patient stopcock set or environment that had an identical biotype to the same organism isolated from hands of providers. We also assessed the efficacy of the current intraoperative cleaning protocol by evaluating isolated potential pathogens identified at the start of case 2. Poor intraoperative cleaning was defined as 1 or more potential pathogens found in the anesthesia environment at the start of case 2 that were not there at the beginning of case 1. We collected clinical and epidemiological data on all the cases to identify risk factors for contamination.One hundred sixty-four cases (82 case pairs) were studied. We identified intraoperative bacterial transmission to the IV stopcock set in 11.5 % (19/164) of cases, 47% (9/19) of which were of provider origin. We identified intraoperative bacterial transmission to the anesthesia environment in 89% (146/164) of cases, 12% (17/146) of which were of provider origin. The number of rooms that an attending anesthesiologist supervised simultaneously, the age of the patient, and patient discharge from the operating room to an intensive care unit were independent predictors of bacterial transmission events not directly linked to providers.The contaminated hands of anesthesia providers serve as a significant source of patient environmental and stopcock set contamination in the operating room. Additional sources of intraoperative bacterial transmission, including postoperative environmental cleaning practices, should be further studied.

    View details for DOI 10.1213/ANE.0b013e3181e7ce18

    View details for Web of Science ID 000285454300016

    View details for PubMedID 20686007

  • Stopcock lumen contamination does not reflect the full burden of bacterial intravenous tubing contamination: Analysis using a novel injection port AMERICAN JOURNAL OF INFECTION CONTROL Muffly, M. K., Beach, M. L., Tong, Y. C., Yeager, M. P. 2010; 38 (9): 734-739


    Prior clinical studies have used injection port lumen culture as a marker of intravenous (IV) fluid system contamination. We hypothesized that culturing injected saline (effluent) is a more sensitive method of detecting IV fluid system bacterial contamination than lumen culture. To test this hypothesis, we compared the incidence of lumen contamination with effluent contamination in a simulated setting. We also measured the effect of a novel injection port protective device (Port Guide; Matrix Tooling, Inc, Wood Dale, IL) on contamination.In this ex vivo study, 33 providers performed 5 injections of 1 mL sterile saline into each of 4 injection port designs: (1) stopcock, (2) stopcock with Port Guide, (3) stopcock with disinfectable needleless closed connector (DNCC), and (4) stopcock with DNCC and Port Guide. The primary outcome was the rate of effluent contamination with simultaneously contaminated injection port lumen.Bacterial organisms were recovered from the effluent in 17 of the 132 injection ports evaluated. Of those 17 injection ports with contaminated effluent, 4 injection port lumens were simultaneously contaminated (24%). Additionally, use of the stopcock with Port Guide significantly reduced effluent contamination.Effluent culture is a more sensitive marker of IV fluid system contamination than injection port lumen culture. A novel protective device on the stopcock (Port Guide) significantly reduced IV fluid system bacterial contamination.

    View details for DOI 10.1016/j.ajic.2010.03.014

    View details for Web of Science ID 000283582500017

    View details for PubMedID 20630618

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