Mutual information: Measuring nonlinear dependence in longitudinal epidemiological data.

Given a large clinical database of longitudinal patient information including many covariates, it is computationally prohibitive to consider all types of interdependence between patient variables of interest. This challenge motivates the use of mutual information (MI), a statistical summary of data interdependence with appealing properties that make it a suitable alternative or addition to correlation for identifying relationships in data. MI: (i) captures all types of dependence, both linear and nonlinear, (ii) is zero only when random variables are independent, (iii) serves as a measure of relationship strength (similar to but more general than R2), and (iv) is interpreted the same way for numerical and categorical data. Unfortunately, MI typically receives little to no attention in introductory statistics courses and is more difficult than correlation to estimate from data. In this article, we motivate the use of MI in the analyses of epidemiologic data, while providing a general introduction to estimation and interpretation. We illustrate its utility through a retrospective study relating intraoperative heart rate (HR) and mean arterial pressure (MAP). We: (i) show postoperative mortality is associated with decreased MI between HR and MAP and (ii) improve existing postoperative mortality risk assessment by including MI and additional hemodynamic statistics.

Adaptation or Revolution: Telemental Health and Advanced Practice Psychiatric Nursing During COVID-19.

OBJECTIVE: This article will describe the current COVID-19 crisis and the evolving mental health concerns associated with it, discuss how mental health practice has changed, and ways in which psychiatric mental health nurse practitioners (PMHNPs) can adapt and prepare for the future. METHOD: A search of current literature on the COVID-19 crisis, and topics relevant to the mental health components associated with the pandemic are reviewed. Telemental health (TMH) and PMHNP practice are discussed as they relate to the unfolding picture of the viral pandemic. RESULTS: The COVID-19 crisis is having far-reaching implications for mental health treatment and in particular for PMHNPs in practice settings. There have been widespread consequences of the containment measures used for the protection and mitigation of the disease. One such result has been the inability of patients to have face-to-face contact with their providers. The role of TMH has become increasingly important as an adaptation in professional practice. CONCLUSION: Technology has rapidly transformed traditional practice due to the COVID-19 crisis and there is strong evidence that it is well accepted by patients and providers. It is incumbent on PMHNPs to embrace TMH and become educated on best practices and TMH services.

Extrema-weighted feature extraction for functional data.

Motivation: Although there is a rich literature on methods for assessing the impact of functional predictors, the focus has been on approaches for dimension reduction that do not suit certain applications. Examples of standard approaches include functional linear models, functional principal components regression and cluster-based approaches, such as latent trajectory analysis. This article is motivated by applications in which the dynamics in a predictor, across times when the value is relatively extreme, are particularly informative about the response. For example, physicians are interested in relating the dynamics of blood pressure changes during surgery to post-surgery adverse outcomes, and it is thought that the dynamics are more important when blood pressure is significantly elevated or lowered. Results: We propose a novel class of extrema-weighted feature (XWF) extraction models. Key components in defining XWFs include the marginal density of the predictor, a function up-weighting values at extreme quantiles of this marginal, and functionals characterizing local dynamics. Algorithms are proposed for fitting of XWF-based regression and classification models, and are compared with current methods for functional predictors in simulations and a blood pressure during surgery application. XWFs find features of intraoperative blood pressure trajectories that are predictive of postoperative mortality. By their nature, most of these features cannot be found by previous methods. Availability and implementation: The R package 'xwf' is available at the CRAN repository: https://cran.r-project.org/package=xwf. Supplementary information: Supplementary data are available at Bioinformatics online.

Effect of A1C and Glucose on Postoperative Mortality in Noncardiac and Cardiac Surgeries.

OBJECTIVE: Hemoglobin A1c (A1C) is used in assessment of patients for elective surgeries because hyperglycemia increases risk of adverse events. However, the interplay of A1C, glucose, and surgical outcomes remains unclarified, with often only two of these three factors considered simultaneously. We assessed the association of preoperative A1C with perioperative glucose control and their relationship with 30-day mortality. RESEARCH DESIGN AND METHODS: Retrospective analysis on 431,480 surgeries within the Duke University Health System determined the association of preoperative A1C with perioperative glucose (averaged over the first 3 postoperative days) and 30-day mortality among 6,684 noncardiac and 6,393 cardiac surgeries with A1C and glucose measurements. A generalized additive model was used, enabling nonlinear relationships. RESULTS: A1C and glucose were strongly associated. Glucose and mortality were positively associated for noncardiac cases: 1.0% mortality at mean glucose of 100 mg/dL and 1.6% at mean glucose of 200 mg/dL. For cardiac procedures, there was a striking U-shaped relationship between glucose and mortality, ranging from 4.5% at 100 mg/dL to a nadir of 1.5% at 140 mg/dL and rising again to 6.9% at 200 mg/dL. A1C and 30-day mortality were not associated when controlling for glucose in noncardiac or cardiac procedures. CONCLUSIONS: Although A1C is positively associated with perioperative glucose, it is not associated with increased 30-day mortality after controlling for glucose. Perioperative glucose predicts 30-day mortality, linearly in noncardiac and nonlinearly in cardiac procedures. This confirms that perioperative glucose control is related to surgical outcomes but that A1C, reflecting antecedent glycemia, is a less useful predictor.

Unique Practice, Unique Place: Exploring Two Assertive Community Treatment Teams in Maine.

Assertive Community Treatment (ACT) is a model of care that provides comprehensive community-based psychiatric care for persons with serious mental illness. This model has been widely documented and has shown to be an evidence-based model of care for reducing hospitalizations for this targeted population. Critical ingredients of the ACT model are the holistic nature of their services, a team based approach to treatment and nurses who assist with illness management, medication monitoring, and provider collaboration. Although the model remains strong there are clear differences between urban and rural teams. This article describes present day practice in two disparate ACT programs in urban and rural Maine. It offers a new perspective on the evolving and innovative program of services that treat those with serious mental illness along with a review of literature pertinent to the ACT model and future recommendations for nursing practice. The success and longevity of these two ACT programs are testament to the quality of care and commitment of staff that work with seriously mentally ill consumers. Integrative care models such as these community-based treatment teams and nursing driven interventions are prime elements of this successful model.

Temporal Trends in Difficult and Failed Tracheal Intubation in a Regional Community Anesthetic Practice.

BACKGROUND: When tracheal intubation is difficult or unachievable before surgery or during an emergent resuscitation, this is a critical safety event. Consensus algorithms and airway devices have been introduced in hopes of reducing such occurrences. However, evidence of improved safety in clinical practice related to their introduction is lacking. Therefore, we selected a large perioperative database spanning 2002 to 2015 to look for changes in annual rates of difficult and failed tracheal intubation. METHODS: Difficult (more than three attempts) and failed (unsuccessful, requiring awakening or surgical tracheostomy) intubation rates in patients 18 yr and older were compared between the early and late periods (pre- vs. post-January 2009) and by annual rate join-point analysis. Primary findings from a large, urban hospital were compared with combined observations from 15 smaller facilities. RESULTS: Analysis of 421,581 procedures identified fourfold reductions in both event rates between the early and late periods (difficult: 6.6 of 1,000 vs. 1.6 of 1,000, P < 0.0001; failed: 0.2 of 1,000 vs. 0.06 of 1,000, P < 0.0001), with join-point analysis identifying two significant change points (2006, P = 0.02; 2010, P = 0.03) including a pre-2006 stable period, a steep drop between 2006 and 2010, and gradual decline after 2010. Data from 15 affiliated practices (442,428 procedures) demonstrated similar reductions. CONCLUSIONS: In this retrospective assessment spanning 14 yr (2002 to 2015), difficult and failed intubation rates by skilled providers declined significantly at both an urban hospital and a network of smaller affiliated practices. Further investigations are required to validate these findings in other data sets and more clearly identify factors associated with their occurrence as clues to future airway management advancements. VISUAL ABSTRACT: An online visual overview is available for this article at http://links.lww.com/ALN/B635.

Operating Room-to-ICU Patient Handovers: A Multidisciplinary Human-Centered Design Approach.

BACKGROUND: Patient handovers (handoffs) following surgery have often been characterized by poor teamwork, unclear procedures, unstructured processes, and distractions. A study was conducted to apply a human-centered approach to the redesign of operating room (OR)-to-ICU patient handovers in a broad surgical ICU (SICU) population. This approach entailed (1) the study of existing practices, (2) the redesign of the handover on the basis of the input of hand over participants and evidence in the medical literature, and (3) the study of the effects of this change on processes and communication. METHODS: The Durham [North Carolina] Veterans Affairs Medical Center SICU is an 11-bed mixed surgical specialty unit. To understand the existing process for receiving postoperative patients in the SICU, ethnographic methods-a series of observations, surveys, interviews, and focus groups-were used. The handover process was redesigned to better address providers' work flow, information needs, and expectations, as well as concerns identified in the literature. RESULTS: Technical and communication flaws were uncovered, and the handover was redesigned to address them. For the 49 preintervention and 49 postintervention handovers, the information transfer score and number of interruptions were not significantly different. However, staff workload and team behaviors scores improved significantly, while the hand over duration was not prolonged by the new process. Handover participants were also significantly more satisfied with the new handover method. CONCLUSIONS: An HCD approach led to improvements in the patient handover process from the OR to the ICU in a mixed adult surgical population. Although the specific handover process would unlikely be optimal in another clinical setting if replicated exactly, the HCD foundation behind the redesign process is widely applicable.

Can we make postoperative patient handovers safer? A systematic review of the literature.

Postoperative patient handovers are fraught with technical and communication errors and may negatively impact patient safety. We systematically reviewed the literature on handover of care from the operating room to postanesthesia or intensive care units and summarized process and communication recommendations based on these findings. From >500 papers, we identified 31 dealing with postoperative handovers. Twenty-four included recommendations for structuring the handover process or information transfer. Several recommendations were broadly supported, including (1) standardize processes (e.g., through the use of checklists and protocols); (2) complete urgent clinical tasks before the information transfer; (3) allow only patient-specific discussions during verbal handovers; (4) require that all relevant team members be present; and (5) provide training in team skills and communication. Only 4 of the studies developed an intervention and formally assessed its impact on different process measures. All 4 interventions improved metrics of effectiveness, efficiency, and perceived teamwork. Most of the papers were cross-sectional studies that identified barriers to safe, effective postoperative handovers including the incomplete transfer of information and other communication issues, inconsistent or incomplete teams, absent or inefficient execution of clinical tasks, and poor standardization. An association between poor-quality handovers and adverse events was also demonstrated. More innovative research is needed to define optimal patient handovers and to determine the effect of handover quality on patient outcomes.

Will the clinicians support the researchers and teachers? Results of a salary satisfaction survey of 947 academic surgeons.

OBJECTIVE: To determine whether academic surgeons are satisfied with their salaries, and if they are willing to forego some compensation to support departmental academic endeavors. BACKGROUND: Increasing financial constraints have led many academic surgery departments to rely on increasingly on clinical revenue generation for the cross-subsidization of research and teach missions. METHODS: Members of 3 academic surgical societies (n = 3059) were surveyed on practice characteristics and attitudes about financial compensation. Univariate and multivariate logistic regression analyses were performed to identify determinants of salary satisfaction and willingness to forego compensation to support academic missions. RESULTS: One thousand thirty-eight (33.9%) surgeons responded to our survey, 947 of whom maintain an academic practice. Of these academic surgeons, 49.7% expressed satisfaction with their compensation. Length of career, administrative responsibility for compensation and membership in the American Surgical Association or the Society of University Surgeons were predictive of salary satisfaction on univariate analysis. Frequent emergency call duty, increased clinical activity, and greater perceived difference between academic and private practice compensation were predictive of salary dissatisfaction. On multivariate analysis, increased clinical activity was inversely associated with both salary satisfaction (adjusted odds ratio [AOR], 0.77; [95% CI: 0.64, 0.94]; P = 0.009) and amount of compensation willingly killed for an academic practice (AOR, 0.71; [0.61, 0.83]; P < 0.0005). CONCLUSIONS: Increasing reliance on clinical revenue to subsidize nonclinical academic missions is disaffecting many academic surgeons. Redefined mission priorities, enhanced nonfinancial rewards, utilization of nonclinical revenue sources (eg, philanthropy, grants), increased efficiency of business practices and/or redesign of fund flows may be necessary to sustain recruitment and retention of young academic surgeons.

"Ghost" publications among applicants to a general surgery residency program.

OBJECTIVE: To determine the incidence of potentially fraudulent (or "ghost") publications in applications to a general surgery residency program. METHODS: Electronic Residency Application Services applications submitted in 2005 to the general surgery residency program were reviewed in an IRB-approved study. No identifiers were collected. Publications were checked against Medline, PubMed, ISI Web of Science, and Google. Nonverifiable publications were then submitted to the medical librarian for verification. Ghost publications were defined as journals, books, or meetings that cannot be verified; verified journals without the listed publication; or verified publications without an applicant author. Data analyses were performed using univariate and multivariate regression analysis for nonparametric data. A p value < 0.05 was considered significant. RESULTS: Four hundred ninety-three applications were received. Thirty-one percent (150 of 493) of applicants listed a total of 596 publications, including 30 abstracts, 359 journal articles, and 207 chapters. Thirty-three percent (196 of 596) of the publications could not be verified: 7 abstracts, 177 journal articles, and 12 chapters. The distribution of ghost publications was skewed toward the journals subgroup (p < 0.001). Positive predictors of ghost publications were age and foreign medical school. The sole negative predictor was enrollment in a top-10 US research medical school. CONCLUSION: A disturbingly substantial fraction of publications listed on Electronic Residency Application Services applications cannot be verified. This might indicate a need for greater mentorship and oversight for medical school applicants. It is unknown whether this behavior predicts lack of integrity in other professional settings.

Predictive indices of morbidity and mortality after liver resection.

OBJECTIVE: To determine if use of Model for End-Stage Liver Disease (MELD) scores to elective resections accurately predicts short-term morbidity or mortality. SUMMARY BACKGROUND DATA: MELD scores have been validated in the setting of end-stage liver disease for patients awaiting transplantation or undergoing transvenous intrahepatic portosystemic shunt procedures. Its use in predicting outcomes after elective hepatic resection has not been evaluated. METHODS: Records of 587 patients who underwent elective hepatic resection and were included in the National Surgical Quality Improvement Program Database were reviewed. MELD score, CTP score, Charlson Index of Comorbidity, American Society of Anesthesiology classification, and age were evaluated for their ability to predict short-term morbidity and mortality. Morbidity was defined as the development of one or more of the following complications: pulmonary edema or embolism, myocardial infarction, stroke, renal failure or insufficiency, pneumonia, deep venous thrombosis, bleeding, deep wound infection, reoperation, or hyperbilirubinemia. The analysis was repeated with patients divided according to their procedure and their primary diagnosis. Parametric or nonparametric analyses were performed as appropriate. Also, a new index was developed by dividing the patients into a development and a validation cohort, to predict morbidity and mortality in patients undergoing elective hepatic resection. ROC curves were also constructed for each of the primary indices. RESULTS: CTP and ASA scores were superior in predicting outcome. Also, patients undergoing resection of primary malignancies had a higher rate of mortality but no difference in morbidity. CONCLUSION: MELD scores should not be used to predict outcomes in the setting of elective hepatic resection.

Is the valve OK or not? Immediate evaluation of a replaced aortic valve.

Transesophageal echocardiography is a crucial tool in intraoperative evaluation of newly implanted/repaired heart valves because suspected valvular malfunction needs to be identified and sometimes surgically corrected. Although color Doppler is often adequate in evaluating the expected regurgitant jets, as well as excluding pathologic paravalvular leaks, spectral Doppler techniques are the most commonly used methods for estimating transvalvular gradients in the operating room. However, these methods are subject to a variety of confounding factors, including subvalvular gradients and pressure recovery. Other methods of valve area estimation should also be used when evaluating a prostethic aortic valve, including the continuity equation and the left ventricular outflow tract/aortic valve velocity ratio.

Intraoperative fluid management during orthotopic liver transplantation.

OBJECTIVE: To assess clinical safety of a low central venous pressure (CVP) fluid management strategy in patients undergoing liver transplantation. DESIGN: Retrospective record review comparing 2 transplant centers, one using the low CVP method and the other using the normal CVP method. SETTING: University-based, academic, tertiary care centers. PARTICIPANTS: Patients undergoing orthotopic cadaveric liver transplantation. INTERVENTIONS: Each center practiced according to its own standard of care. Center 1 maintained an intraoperative CVP <5 mmHg using fluid restriction, nitroglycerin, forced diuresis, and morphine. If pressors were required to maintain systolic arterial pressure >90 mmHg, phenylephrine or norepinephrine was used. At center 2, CVP was kept 7 to 10 mmHg and mean arterial pressure >75 mmHg with minimal use of vasoactive drugs. MEASUREMENTS AND MAIN RESULTS: Data collected included United Network for Organ Sharing status, surgical technique, intraoperative transfusion rate, preoperative and peak postoperative creatinine, time spent in intensive care unit and hospital, incidence of death, and postoperative need for hemodialysis. Principal findings include an increased rate of transfusion in the normal CVP group but increased rates of postoperative renal failure (elevated creatinine and more frequent need for dialysis) and 30-day mortality in the low CVP group. CONCLUSIONS: Despite success in lowering blood transfusion requirements in liver resection patients, a low CVP should be avoided in patients undergoing liver transplantation.

Determining benchmarks for evaluation and management coding in an academic division of general surgery.

BACKGROUND: Academic divisions of general surgery are facing ever-increasing financial pressures. Cost-cutting is a common approach to maintaining profitability, but strategies to increase revenue should not be ignored. One specific avenue for enhanced revenue generation in general surgery is that of coding for evaluation and management (E&M). Although this is the financial life-blood for many of the consultative services in departments of medicine, E&M coding is an often neglected and misunderstood component of surgical care. STUDY DESIGN: The financial records for the Division of General Surgery were reviewed for the period of January 2001 to June 2003. Specifically, charges and receipts for inpatient procedures and hospital visits (CPT codes 99231, 99232, and 99233) were determined. The analysis was limited to surgeons with a primary clinical focus based at the University hospital rather than the neighboring community or Veteran's Affairs hospitals. In addition, ICD-9 and All Patient Refined Diagnosis Related Groups (APR-DRG) data were analyzed to determine the surgeon-specific number of inpatients and inpatient-days with more than one ICD-9 code or secondary ICD-9 codes, or both, or an APR-DRG severity of illness score of 2, 3, or 4. These categories were defined to determine the number of inpatient-days for which E&M coding could be billed for management of secondary medical diagnoses. RESULTS: Analysis demonstrates that actual E&M charges were 40% to 47% of predicted minimums for E&M charges for the period under study. In theory, this result translates into an annual gain in receipts of 400,000 dollars to 600,000 dollars. CONCLUSIONS: We conclude that the ICD-9 and APR-DRG models may serve as benchmarks to determine the limits for E&M revenue stream, and E&M coding may represent an underutilized source of revenue among academic departments of surgery.

Optimization of operating room allocation using linear programming techniques.

BACKGROUND: New and innovative approaches must be used to rationally allocate scarce resources such as operating room time while simultaneously optimizing the associated financial return. In this article we use the technique of linear programming to optimize allocation of OR time among a group of surgeons based on professional fee generation. STUDY DESIGN: For the period of December 1, 2000, to July 31, 2002, the following individualized data were obtained for the Division of General Surgery at Duke University Medical Center: allocated OR time (hours), case mix as determined by CPT codes, total OR time used, and normalized professional charges and receipts. Inpatient, outpatient, and emergency cases were included. The Solver linear programming routine in Microsoft Excel (Microsoft Corp.) was used to determine the optimal mix of surgical OR time allocation to maximize professional receipts. RESULTS: Our model of optimized OR allocation would maximize weekly professional revenues at 237,523 US dollars, a potential increase of 15% over the historical value of 207,700 US dollars or an annualized increase of approximately 1.5 million US dollars. CONCLUSIONS: Our results suggest that mathematical modeling techniques used in operations research, management science, or decision science may rationally optimize OR allocation to maximize revenue or to minimize costs. These techniques may optimize allocation of scarce resources in the context of the goals specific to individual academic departments of surgery.

Emergencies after liver transplantation.

Liver transplantation has become the procedure of choice for a wide variety of patients with end-stage liver disease. Perioperative morbidity and mortality have decreased dramatically over the past two decades, and superior graft and patient survival rates are now routine. Despite these advances, however, there remain several potentially lethal possibilities that may complicate the immediate postoperative period. Failure of the graft to regain any useful metabolic activity is known as primary nonfunction, and almost uniformly requires retransplantation for any hope of survival. Lesser degrees of immediate dysfunction require experienced clinical judgment as to the probability of sustaining long-term patient viability. Another potentially catastrophic development is thrombosis of the grafted hepatic artery. This is sometimes successfully managed by surgical reconstruction. It may develop immediately, or present insidiously much later. Thrombosis of the portal vein, while not usually fatal, can significantly complicate the immediate course, carrying with it a significant risk of sepsis. Close monitoring of patients in the period following liver transplantation is crucial, as prompt diagnosis and early intervention directly affects the patient's chances of survival.