Generalized Confidence Intervals for Ratios of Standard Deviations Based on Log-Normal Distribution when Times Follow Weibull Distributions.

Modern anesthetic drugs ensure the efficacy of general anesthesia. Goals include reducing variability in surgical, tracheal extubation, post-anesthesia care unit, or intraoperative response recovery times. Generalized confidence intervals based on the log-normal distribution compare variability between groups, specifically ratios of standard deviations. The alternative statistical approaches, performing robust variance comparison tests, give P-values, not point estimates nor confidence intervals for the ratios of the standard deviations. We performed Monte-Carlo simulations to learn what happens to confidence intervals for ratios of standard deviations of anesthesia-associated times when analyses are based on the log-normal, but the true distributions are Weibull. We used simulation conditions comparable to meta-analyses of most randomized trials in anesthesia, n ≈ 25 and coefficients of variation ≈ 0.30 . The estimates of the ratios of standard deviations were positively biased, but slightly, the ratios being 0.11% to 0.33% greater than nominal. In contrast, the 95% confidence intervals were very wide (i.e., > 95% of P ≥ 0.05). Although substantive inferentially, the differences in the confidence limits were small from a clinical or managerial perspective, with a maximum absolute difference in ratios of 0.016. Thus, P < 0.05 is reliable, but investigators should plan for Type II errors at greater than nominal rates.

Forecasting Caseload of Critically Ill Patients Who Are Alert and Without Delirium for at Least Two Consecutive Days for the Assessment of Their Psychological Distress.

INTRODUCTION: One-quarter of alert, non-delirious patients in critical care units report significant psychological distress. Treatment of this distress depends upon identifying these high-risk patients. Our aim was to characterize how many critical care patients remain alert and without delirium for at least two consecutive days and could thus predictably undergo evaluation for distress. METHODS: This retrospective cohort study used data from a large teaching hospital in the United States of America, from October 2014 to March 2022. Patients were included if they were admitted to one of three intensive care units, and for >48 hours all delirium and sedation screenings were negative (Riker sedation-agitation scale four, calm and cooperative, and no delirium based on all Confusion Assessment Method for the Intensive Care Unit scores negative and all Delirium Observation Screening Scale less than three). Means and standard deviations of means for counts and percentages are reported among the most recent six quarters. Means and standard deviations of means for lengths of stay were calculated among all N=30 quarters. The Clopper-Pearson method was used to calculate the lower 99% confidence limit for the percentages of patients who would have had at most one assessment of dignity-related distress before intensive care unit discharge or change in mental status. RESULTS: An average of 3.6 (standard deviation 0.2) new patients met the criteria daily. The percentages of all critical care patients (20%, standard deviation 2%) and hours (18%, standard deviation 2%) meeting criteria decreased slightly over the 7.5 years. Patients spent a mean of 3.8 (standard deviation 0.1) days awake in critical care before their condition or site changed. In the context of assessing distress and potentially treating it before the date of change of condition (e.g., transfer), 66% (6818/10314) of patients would have zero or one assessment, lower 99% confidence limit of 65%. CONCLUSIONS: Approximately one-fifth of critically ill patients are alert and without delirium and thus could be evaluated for distress during their intensive care unit stay, mostly during a single visit. These estimates can be used to guide workforce planning.

Quantifying and Interpreting Inequality in Surgical Site Infections per Quarter Among Anesthetizing Locations and Specialties.

Background Earlier studies have shown that prevention of surgical site infection can achieve net cost savings when targeted to operating rooms with the most surgical site infections. Methodology This retrospective cohort study included all 231,057 anesthetics between May 2017 and June 2022 at a large teaching hospital. The anesthetics were administered in operating rooms, procedure rooms, radiology, and other sites. The 8,941 postoperative infections were identified from International Classification of Diseases diagnosis codes relevant to surgical site infections documented during all follow-up encounters over 90 days postoperatively. To quantify the inequality in the counts of infections among anesthetizing locations, the Gini index was used, with the Gini index being proportional to the sum of the absolute pairwise differences among anesthetizing locations in the counts of infections. Results The Gini index for infections among the 112 anesthetizing locations at the hospital was 0.64 (99% confidence interval = 0.56 to 0.71). The value of 0.64 is so large that, for comparison, it exceeds nearly all countries' Gini index for income inequality. The 50% of locations with the fewest infections accounted for 5% of infections. The 10% of locations with the most infections accounted for 40% of infections and 15% of anesthetics. Among the 57 operating room locations, there was no association between counts of cases and infections (Spearman correlation coefficient r = 0.01). Among the non-operating room locations (e.g., interventional radiology), there was a significant association (Spearman r = 0.79). Conclusions Targeting specific anesthetizing locations is important for the multiple interventions to reduce surgical site infections that represent fixed costs irrespective of the number of patients (e.g., specialized ventilatory systems and nightly ultraviolet-C disinfection).

Patients Undergoing Elective Inpatient Major Therapeutic Procedures in Florida Had No Significant Change in Hospital Mortality or Mortality-Related Comorbidities Between 2007 and 2019.

BACKGROUND: In a recent study, rapid response team implementation at 1 hospital was associated with only a 0.1% reduction in inpatient mortality from 2005 to 2018, characterized in the accompanying editorial as a "tepid" improvement. The editorialist postulated that an increase in the degree of illness of hospitalized patients might have masked a larger reduction that otherwise might have occurred. Impressions of greater patient acuity during the studied period might have been an artifact of efforts to document more comorbidities and complications, possibly facilitated by the change in diagnosis coding from the International Classification of Diseases , Ninth Revision ( ICD-9 ) to the Tenth Revision ( ICD-10 ). METHODS: We used inpatient data from every nonfederal hospital in Florida from the last quarter of 2007 through 2019. We studied hospitalizations for major therapeutic surgical procedures with lengths of stay ≥2 days. Using logistic regression with clustering by the Clinical Classification Software (CCS) code of the primary surgical procedure, we evaluated the trends for decreased mortality, changes in the prevalence of Medicare Severity Diagnosis Related Groups (MS-DRG) with complications or comorbidities (CC) or major complications or major comorbidities (MCC), and changes in the van Walraven index (vWI), a measure of patient comorbidities associated with increased inpatient mortality. Also incorporated in the modeling was the change from ICD-9 to ICD-10 . RESULTS: There were 3,151,107 hospitalizations comprising 130 distinct CCS codes and 453 MS-DRG groups among 213 hospitals. Despite a progressive increase of 4.1% per year in the odds of a CC or MCC ( P = .001), there were no significant changes in the marginal estimates of in-house mortality over time (net estimated decrease, 0.036%; 99% confidence interval [CI], -0.168% to 0.097%; P = .49). There was also absence of a significantly greater fraction of discharges with vWI >0 attributable to the year of the study (odds ratio, 1.017 per year; 99% CI, 0.995-1.041). The changes in MS-DRG to those with CC or MCC were not increased significantly from either the ICD-10 coding change or the number of years after the change. CONCLUSIONS: Consistent with the previous study, there was at most a small decrease in the mortality rate over a 12-year period. We found no reliable evidence that patients undergoing elective inpatient surgical procedures were any sicker in 2019 than in 2007. There were substantively more comorbidities and complications documented over time, but this was unrelated to the change to ICD-10 coding.

Estimating costs of anesthesia supplies for intraoperative infection control.

BACKGROUND: Some costs for anesthesia supplies to reduce intraoperative infections depend on the procedure and duration of the case. For regular anesthesia supplies and medications, costs are linearly related to American Society of Anesthesiologists' Relative Value Guide units, known for nearly all cases in the United States of America. We hypothesized linear association between costs of infection control items and anesthesia units. METHODS: A prospective observational study of 38 surgical cases was performed. Usage of anesthesia infection control supplies was recorded: alcohol hand dispensers, microfiber cloths for machine disinfection, and disinfecting and cleaning caps for syringe tips, Luer connectors, and stopcocks. Cost per case was calculated using 2022 US dollar payments for those items. RESULTS: Using least squares linear regression to associate the anesthesia units (base + time) with supply costs, in addition to intercept and linear slope, none of 5 potential extra non-linear terms were significant (all P ≥ .46). Further assessment showed lack of fit to a quadratic model. Pearson linear correlation coefficient between cost and units was 0.88. An example was created showing how to forecast annual infection control supply costs for anesthesia based on the linear model. CONCLUSIONS: For purposes of predicting intraoperative anesthesia supplies to reduce bacterial transmission in the anesthesia workspace, a valid approach is to assume a linear association with the total anesthesia units, a predictor generally known for all anesthetics.

More surgery in December among US patients with commercial insurance is offset by unrelated but lesser surgery among patients with Medicare insurance.

STUDY OBJECTIVE: Evaluate whether there is more surgery (in the US State of Florida) at the end of the year, specifically among patients with commercial insurance. DESIGN: Observational cohort study. SETTING: The 712 facilities in Florida that performed inpatient or outpatient elective surgery from January 2010 through December 2019. RESULTS: Among patients with commercial insurance, December had more cases than November (1.108 [1.092-1.125]) or January (1.257 [1.229-1.286]). In contrast, among patients with Medicare insurance (traditional or managed care), December had fewer cases than November (ratio 0.917 [99% confidence interval 0.904-0.930]) or January (0.823 [0.807-0.839]) of the same year. Summing among all cases, December did not have more cases than November (ratio 1.003 [0.992-1.014]) or January (0.998 [0.984-1.013]). Comparing December versus November (January) ratios for cases among patients with commercial insurance to the corresponding ratios for cases among patients with Medicare, years with more commercial insurance cases had more Medicare cases (Spearman rank correlation +0.36 [+0.25], both p < 0.0001). CONCLUSIONS: In the US State of Florida, although some surgeons' procedural workloads may have seasonal variation if they care mostly for patients with one category of insurance, surgical facilities with patients undergoing many procedures will have less variability. Importantly, more commercial insurance cases were not causing Medicare cases to be postponed or vice-versa, providing mechanistic explanation for why forecasts of surgical demand can reasonably be treated as the sum of the independent workloads among many surgeons.

Frequency of Follow-Up Assessment for Post-Intensive Care Syndrome Among Alert and Non-Delirious Critically Ill Patients.

INTRODUCTION: Many patients surviving critical illness develop post-intensive care syndrome, a constellation of psychological, physical, and cognitive symptoms which can have long-term consequences. Physicians and nurses at our large rural teaching hospital treat many of the critically ill patients in the state. Our focus has been the subset of these critically ill patients who were alert and not delirious for multiple consecutive days. The goal of our retrospective cohort study was to estimate the percentage of the patients with multiple intensive care unit days alert and not delirious who had follow-up assessments for post-intensive care syndrome within 15 months. METHODS: The inclusion criteria for the case series of randomly selected patients were: adults defined as patients aged >17 years on the date of hospital admission between October 2014 and December 2020, present in a critical care unit at noon one day and continually so for another 48 hours, and for that interval, ≥≥48 hours had every Riker sedation-agitation scale "4, calm and cooperative," as well as either all Confusion Assessment Method for the Intensive Care Unit scores negative (i.e., no delirium) or Delirium Observation Screening Scale <3 (i.e., no delirium). Each patient was then categorized as having a full one-year follow-up if there was an encounter at our hospital between 12 and 15 months after the last date meeting study inclusion criteria. All follow-up appointments completed within 15 months of the index intensive care unit stay were screened for systematic assessment for psychological and cognitive sequelae of critical illness. RESULTS: From a manual chart review of 366 records, 73 patients were found with follow-up ≥≥12 months. There were 21% (15/73) of the patients assessed for post-intensive care syndrome sequelae (99% confidence interval 10%-35%). CONCLUSIONS: The fact that far fewer than half the patients had documented assessments suggests that retrospective studies should not be used to judge the incidence of post-intensive care syndrome at our hospital. Prospective observational studies would be needed to judge outcomes among critically ill patients with multiple consecutive days of alert and without delirium.

Pain Medicine Board Certification Status Among Physicians Performing Interventional Pain Procedures in the State of Florida Between 2010 and 2016.

BACKGROUND: The US Department of Health and Human Services has recommended that physicians performing interventional pain procedures be credentialed based on criteria based guidelines and minimum training requirements. OBJECTIVES: To quantitatively assess gaps in certification related to pain medicine fellowship requirements, we studied the distribution of such procedures in Florida between 2010 and 2016. STUDY DESIGN: This research involved a retrospective analysis with a sample size of n = 1,885,442 interventional pain procedures. SETTING: Data describing interventional pain procedures performed in Florida between January 2010 and December 2016 were obtained from the Florida Department of Health. The National Provider Identifier file and board certification lists from the American Board of Medical Specialties (ABMS), the American Board of Pain Medicine (ABPM), and the American Board of Interventional Pain Physicians (ABIPP) corresponding to this time frame were also obtained. METHODS: The datasets were linked to determine the specialty of physicians performing interventional pain procedures, and whether or not they were pain medicine diplomates of the ABMS, the ABPM, or the ABIPP. The similarity index theta was calculated for the distribution of interventional pain procedure codes among medical specialty groups, and with respect to the practitioners' pain medicine board certification status. RESULTS: Of the interventional pain procedures, anesthesiologists performed 63.5%, physiatrists 19.1%, neurologists or psychiatrists 5.2%, and other practitioners 12.3%. Among procedures performed by anesthesiologists, physiatrists, and psychiatrists or neurologists, 66.2%, 50.3%, and 50.4% were by ABMS pain board-certified practitioners, respectively. Practitioners without ABMS pain medicine boards performed 45.8% of interventional pain procedures. Practitioners without such boards from either the ABMS, ABPM, or ABIPP performed 37.7%. There was very large similarity (theta > 0.9) in the distribution of procedures comparing ABMS pain medicine board-certified practitioners to non-ABMS pain medicine board-certified anesthesiologists, physiatrists, or all other specialties. LIMITATIONS: In countries other than the United States, where pain medicine board certification is relatively recent, there may be a higher percentage of interventional pain procedures performed by individuals without certification than we report. In "opt-out" states, where nurse anesthetists can independently perform interventional pain procedures, the percentage of interventional pain procedures performed by individuals without physician pain medicine board certification may also be higher. The datasets we used do not contain information to allow assessment of outcomes or effectiveness resulting from pain medicine board certification. CONCLUSIONS: Approximately one-third of interventional pain procedures were performed by physicians without at least 1 of the 3 pain medicine board certifications. In addition, the practitioners performed very similar distributions of procedures (i.e., those without pain medicine board certification, overall, have not restricted their practice). These results suggest the need for additional accredited pain medicine fellowship training positions for newly graduated residents. The results also show that, for the recommendations of the Department of Health and Human Services to be satisfied, physicians without board certification performing intervention procedures would need to obtain ABPM or ABIPP certification, or ABMS certification after completion of a full-time Accreditation Council of Graduate Medical Education pain medicine fellowship. KEY WORDS: Chronic pain, education, medical, graduate, specialty boards.

Importance of operating room case scheduling on analyses of observed reductions in surgical site infections from the purchase and installation of capital equipment in operating rooms.

BACKGROUND: We review the impact of the consequences of operating room (OR) management decision making on power analyses for observational studies of surgical site infections (SSIs) among patients receiving care in ORs with interventions versus without interventions involving physical changes to ORs. Examples include ventilation systems, bactericidal lighting, and physical alterations to ORs. METHODS: We performed a narrative review of operating room management and surgical site infection articles. We used 10-years of operating room data to estimate parameters for use in statistical power analyses. RESULTS: Creating pivot tables or monthly control charts of SSI per case by OR and comparing among ORs with or without intervention is not recommended. This approach has low power to detect a difference in SSI rates among the ORs with or without the intervention. The reason is that appropriate OR case scheduling decision making causes risk factors for SSI to differ among ORs, even when stratifying by surgical specialty. Such risk factors include case duration, urgency, and American Society of Anesthesiologists' Physical Status. Instead, analyze SSI controlling for the OR, where the patient had surgery, and matching patients using these variables is preferable. With α = 0.05, 600 cases per OR, 5 intervention ORs, and 5 or 1 control patients for each intervention patient, reasonable power (≅94% or 78%, respectively) can be achieved to detect reductions (3.6% to 2.4%) in the incidence of SSI between ORs with or without the intervention. CONCLUSIONS: By using this matched cohort design, the effect of the purchase and installation of capital equipment in ORs on SSI can be evaluated meaningfully.

Assessment of anesthesia machine redesign on cleaning of the anesthesia machine using surface disinfection wipes.

BACKGROUND: The use of surface disinfection wipes after induction of anesthesia improves anesthesia machine cleaning. We assessed whether anesthesia machine surface redesign improves disinfection wipe cleaning by anesthesia residents. METHODS: Sixteen anesthesia residents were assigned to 2 cases in series. The first case was randomly assigned to regional knee or hip surgery, a brief or detailed checklist, and the Perseus A500 (redesigned) or GE Aespire 7900 (conventional) machine. The second case was assigned to the opposite for each condition. Setup checklists included cleaning instructions. Eight machine sites representing redesign were contaminated with fluorescent gel prior to setup and reassessed after setup to assess cleaning efficacy. Cleaning was compared by fluorescence quantification of before and after setup images. Our primary hypothesis was that, overall, more sites would be cleaned on the Perseus machine. Our secondary hypothesis was that redesign would affect some sites. RESULTS: Overall, the number of sites cleaned did not differ between machines (median 0.74 more sites out of 8 for the Perseus A500; 25th and 75th percentiles, -0.34 and 1.04; P = .093). However, greater cleaning was observed for the work surface and manual bag arm/hose of the Perseus machine (0.58 more sites out of 2; 25th and 75th percentiles, 0.35 and 1.05; P = .0004). CONCLUSIONS: The number of sites cleaned overall did not differ between the conventional and redesigned Perseus A500 machines. However, the redesigned work surface and smooth manual bag arm features improved resident cleaning with surface disinfection wipes.

Trends in Direct Hospital Payments to Anesthesia Groups: A Retrospective Cohort Study of Nonacademic Hospitals in California.

BACKGROUND: In addition to payments for services, anesthesia groups in the United States often receive revenue from direct hospital payments. Understanding the magnitude of these payments and their association with the hospitals' payer mixes has important policy implications. METHODS: Using a dataset of financial reports from 240 nonacademic California hospitals between 2002 and 2014, the authors characterized the prevalence and magnitude of direct hospital payments to anesthesia groups, and analyzed the association between these payments and the fraction of anesthesia revenue derived from public payers (e.g., Medicaid). RESULTS: Of hospitals analyzed, 69% (124 of 180) made direct payments to an anesthesia group in 2014, compared to 52% (76 of 147) in 2002; the median payment increased from $242,351 (mean, $578,322; interquartile range, $72,753 to $523,861; all dollar values in 2018 U.S. dollars) to $765,128 (mean, $1,295,369; interquartile range, $267,006 to $1,503,163) during this time period. After adjusting for relevant covariates, hospitals where public insurers accounted for a larger fraction of anesthesia revenues were more likely to make direct payments to anesthesia groups (ß = 0.45; 95% CI, 0.10 to 0.81; P = 0.013), so that a 10-percentage point increase in the fraction of anesthesia revenue derived from public payers would be associated with a 4.5-percentage point increase in the probability of receiving any payment. Among hospitals making payments, our results (ß = 2.10; 95% CI, 0.74 to 3.45; P = 0.003) suggest that a 1-percentage point increase in the fraction of anesthesia revenue derived from public payers would be associated with a 2% relative increase in the amount paid. CONCLUSIONS: Direct payments from hospitals are becoming a larger financial consideration for anesthesia groups in California serving nonacademic hospitals, and are larger for groups working at hospitals serving publicly insured patients.

Quantitative Assessment of Statistical Reviews of Patient Safety Research Articles.

OBJECTIVES: For 8.5 consecutive years, all patient safety articles of a journal underwent statistical review before publication. We sought to establish the prevalence of statistical themes in the statistical reviews, consideration of contemporary statistical methods, and their associations with time to journal receipt of authors' revision. METHODS: An initial set of statistical themes was created using the statistical editor's notes. For example, for the statistical theme of "CONSORT checklist," the search term needed was "CONSORT." A complete (exhaustive) list of additional themes was obtained inductively. RESULTS: Among the 273 subsequent reviews for manuscripts that were ultimately accepted, the number of paragraphs that included a theme of a statistical method was only weakly associated with longer revision times (Kendall τ = 0.139 ± 0.039, P = 0.0004). Among the total 3274 paragraphs of statistical reviews, 72.2% did not include a theme of a statistical method (e.g., the editor instead asked the authors to clarify what statistical method had been used) (95% confidence interval [CI] = 70.6%-73.7%, P < 0.0001 versus 50%).Among the 207 manuscripts with a review that included a statistical method, 47.3% included a contemporary topic (e.g., generalized pivotal methods) (95% CI = 40.4%-54.4%). However, among the 911 corresponding paragraphs of statistical review comments, only 16.0% included a contemporary theme (95% CI = 13.7%-18.6%). CONCLUSIONS: The revised versions of patient safety articles, which are eventually to be accepted for publication, have many statistical limitations especially in the reporting (writing) of basic statistical methods and results. The results suggest a need for education of patient safety investigators to include statistical writing.

Determination of Geolocations for Anesthesia Specialty Coverage and Standby Call Allowing Return to the Hospital Within a Specified Amount of Time.

BACKGROUND: For emergent procedures, in-house teams are required for immediate patient care. However, for many procedures, there is time to bring in a call team from home without increasing patient morbidity. Anesthesia providers taking subspecialty or backup call from home are required to return to the hospital within a designated number of minutes. Driving times to the hospital during the hours of call need to be considered when deciding where to live or to visit during such calls. Distance alone is an insufficient criterion because of variable traffic congestion and differences in highway access. We desired to develop a simple, inexpensive method to determine postal codes surrounding hospitals allowing a timely return during the hours of standby call. METHODS: Pessimistic travel times and driving distances were calculated using the Google distance matrix application programming interface for all N = 136 postal codes within 60 great circle ("straight line") miles of the University of Miami Hospital (Miami, FL) during all 108 weekly standby call hours. A postal code was acceptable if the estimated longest driving time to return to the hospital was ≤60 minutes (the anesthesia department's service commitment to start an urgent case during standby call). Linear regression (with intercept = 0) minimizing the mean absolute percentage difference between the distances (great circle and driving) and the pessimistic driving times to return to the hospital was performed among all 136 postal codes. Implementation software written in Python is provided. RESULTS: Postal codes allowing return to the studied hospital within the specified interval were identified. The linear regression showed that driving distances correlated poorly with the longest driving time to return to the hospital among the 108 weekly call hours (mean absolute percentage error = 25.1% ± 1.7% standard error [SE]; N = 136 postal codes). Great circle distances also correlated poorly (mean absolute percentage error = 28.3% ± 1.9% SE; N = 136). Generalizability of the method was determined by successful application to a different hospital in a rural state (University of Iowa Hospital). CONCLUSIONS: The described method allows identification of postal codes surrounding a hospital in which personnel taking standby call could be located and be able to return to the hospital during call hours on every day of the week within any specified amount of time. For areas at the perimeter of the acceptability, online distance mapping applications can be used to check driving times during the hours of standby call.

Lack of a substantive effect of insurance and the national US payment system on the relative distribution of surgical cases among hospitals in the State of Iowa: A retrospective, observational, cohort study.

STUDY OBJECTIVE: Our aim was to quantify the extent to which the distribution of patients among payers and changes to the payers' policies has influenced the market of surgery among hospitals in a relatively rural state. DESIGN: Retrospective cohort study. SETTING: Iowa Hospital Association data analyzed were from 2007 through 2016 for the N = 121 hospitals with at least one case performed that included a major therapeutic procedure. MEASUREMENTS: We used five categories of payer (e.g., Medicare), five categories of patient age (e.g., 18 to 64 years), and three categories of patient residence location (e.g., neither from the county of the hospital nor from a county contiguous to the county of the hospital). MAIN RESULTS: Sorting hospitals in descending sequence of numbers of surgical cases, depending on year, the top 10% of hospitals performed 58.4% to 59.2% of the cases. Increases in numbers of cases among patients with commercial insurance increased the heterogeneity among hospitals in numbers of surgical cases (P < 0.0001). However, the magnitude of the effect was very small, with an estimated relative marginal effect on the overall Gini index of only 0.9% ±â€¯0.2% (SE). Increases in numbers of cases of patients with Medicare insurance reduced the heterogeneity in numbers of cases among hospitals (P < 0.0001), but also with very small magnitude (-0.9% ±â€¯0.2%). In contrast, factors encouraging patient travel contributed to larger hospitals becoming larger, and smaller hospitals becoming smaller (3.9% ±â€¯0.7%, P < 0.0001). CONCLUSIONS: We found the absence of a substantive effect of insurance and national US payment systems on the relative distribution of surgical cases among hospitals. Anesthesia groups should focus on payer and payment reform in terms of their effects on payment rates (e.g., average payment per relative value guide unit), not on their potential effects on hospital caseloads.

Hospitals with greater diversities of physiologically complex procedures do not achieve greater surgical growth in a market with stable numbers of such procedures.

STUDY OBJECTIVE: Although having a large diversity of types of procedures has a substantial operational impact on the surgical suites of hospitals, the strategic importance is unknown. In the current study, we used longitudinal data for all hospitals and patient ages in the State of Florida to evaluate whether hospitals with greater diversity of types of physiologically complex major therapeutic procedures (PCMTP) also had greater rates of surgical growth. DESIGN: Observational cohort study. SETTING: 1479 combinations of hospitals in the State of Florida and fiscal years, 2008-2015. MEASUREMENTS: The types of International Classification of Diseases, Ninth revision, Clinical Modification (ICD-9-CM) procedures studied were PCMT, defined as: a) major therapeutic procedure; b) >7 American Society of Anesthesiologists base units; and c) performed during a hospitalization with a Diagnosis Related Group with a mean length of stay ≥4.0days. The number of procedures of each type of PCMTP commonly performed at each hospital was calculated by taking 1/Herfindahl index (i.e., sum of the squares of the proportions of all procedures of each type of PCMTP). MAIN RESULTS: Over the 8 successive years studied, there was no change in the number of PCMTP being performed (Kendall's τb=-0.014±0.017 [standard error], P=0.44; N=1479 hospital×years). Busier and larger hospitals commonly performed more types of PCMTP, respectively categorized based on performed PCMTP (τ=0.606±0.017, P<0.0001) or hospital beds (τ=0.524±0.017, P<0.0001). There was no association between greater diversity of types of PCMTP commonly performed and greater annual growth in numbers of PCMTP (τ=0.002±0.019, P=0.91; N=1295 hospital×years). Conclusions were the same with multiple sensitivity analyses. Post hoc, it was recognized that hospitals performing a greater diversity of PCMTP were more similar to the aggregate of other hospitals within the same health district (τ=0.550±0.017, P<0.0001). CONCLUSIONS: During a period with no overall growth in PCMTP, hospitals with greater diversities of types of PCMTP had growth that was, at most, minimally larger than that of the smaller hospitals, and vice-versa. Diversity is important operationally. From the perspective of delivering surgical care within a market, the unique contributions of each large teaching hospital performing many different types of PCMTP needs to be considered relative to the combined capabilities of other hospitals in its region.