Biostatistics applications in surgery, anesthesiology, and emergency and critical care medicine Clinic Notes (2020)

2020 December 16

George Lin (Alex Langerman), Surgery/Otolaryngology

  • Mentor will be joining. The goal of our project is to collect informed consent forms along with a short survey from ~100 medical centers across the nation to understand variation in the components of informed consent. For this clinic, we will come with 2019 American Hospital Association data in an excel sheet. We would like to discuss approaches to sample these hospitals in way that represents surgical case volume across the US. In addition, we would like to discuss ways to quantify and organize the components of informed consent documents once we have gathered our data. Mentor confirmed. VICTR biostatistics voucher.
  • Dandan Liu and Wu Gong attended the clinic. The investigators have a clear idea of what they want to do. Dandan suggested that they should pay attention to the characteristics of hospitals. The investigators expressed their interest in applying VICTR voucher. We are not sure if VICTR voucher covers the study design part. But we thought we should get involved as early as possible if we have to.
  • Dandan Liu also suggested the investigator to apply for a VICTR studio to seek input from other experts beyond Biostatistician about the study desing. Once the study design is in good shape, the investigator could apply for VICTR voucher to cover the analysis part.

Kevin Patel (Trent Rosenbloom, Wael Alrifai), Neonatology

  • My project involves using patient data from epic to predict NICU discharge within 5 days. We have a model built already, as well as the variables we plan to collect. My question involves the best tools to evaluate the model. Mentor confirmed. VICTR biostatistics voucher.
  • Dandan Liu and Wu Gong attended the clinic. It is a clinical model and Dandan helped them clarify some questions. And Dandan thought they were not ready for a VICTR voucher yet.

RESCHEDULED: Amany Alshibli (Bantayehu Sileshi), Anesthesiology

  • We are conducting a retrospective analysis of perioperative data collected in REDCap as part of the ImPACT Africa program to understand the effect of the COVID-19 pandemic on surgical care and outcomes. I have done some work analyzing missingness of the data and have some questions on how this will affect my analysis and if we should perform imputation. I would also like to go over some questions from my univariate analysis and logistic regression if time allows. We are anticipating submitting a conference abstract by mid-January. Mentor confirmed.

2020 December 09

Jonathan Boyd (Jennifer King), Pediatric Critical Care

  • My overall project relates to graduate medical education and resident learning on the Pediatric Critical Care Resident rotation, which has been revised using principles of curriculum design (e.g. Needs assessment, exploring what instructional methods are being used, how they could be changed, and assessing impact of the revised curriculum). I have incorporated multiple choice test questions given at the beginning and end of the rotation as a knowledge assessment. The main question I would like to address is what analysis(es) is/are most appropriate to determine if scores on the knowledge tests are different when comparing pre curriculum implementation (~15-20 residents near the end of the 19-20 academic year) to post curriculum implementation (residents rotating starting in July 2020 once curricular revisions were implemented). I have also collected some demographic data (specific year of training, prior ICU rotations) and am interested if it is feasible to perform any type of subgroup analysis or otherwise address confounders given that residents may have diverse experiences prior to rotating in the PICU. Mentor confirmed.

Ryan Stark, Pediatric Critical Care

  • I have a pair of subjects who underwent an intervention at 2 time points and correlated the relationship between two variables at each time point using a Spearman r. I want to know how to compare two Spearman r.

2020 December 02

Michael Topf, Otolaryngology - Head and Neck Surgery

  • NCDB project on rate of positive margins in head and neck cancer patients over 10 year period and effect of adjuvant chemotherapy in this setting. Data has been collected and stats have been performed. I would like to get someone from biostats department on board as I think there is potential for publication in high impact journal such as JAMA-Oncology. VICTR biostatistics voucher.

2020 November 18

Jeremy Joseph (Brian Drolet), Plastic Surgery

  • Request our same previous biostatistician, Dandan Liu, to discuss Fitbit studies. We have already discussed one study with DIEP patients using historical controls. Another study will be with breast reduction patients; this one will also be comparing historical controls. I would like to combine the two above into one VICTR application for biostats support and request for funding for more devices. A 3rd Fitbit study that is funded from an external source is in abdominoplasty - the design for this will be a RCT. For this abdominoplasty study, we have $3000 for biostats support from a societal grant. In all 3 of these, we are comparing the time it takes for patients to return to baseline step count in the “aggressive ambulation protocol” (including +Fitbit notifications) vs those not getting these Fitbit notifications. Mentor confirmed. VICTR biostatistics voucher.

Jaclyn Lee (Seth Davis), Otolaryngology/Head & Neck Surgery

  • Help with power analysis and non-inferiority study. Mentor confirmed.

RESCHEDULED: Caitlin Jacowski (Uchenna Anani), Neonatology

  • Survey of physicians of 3 different subspecialties (OB/MFM, neonatology, Cardiology) of their opinions regarding interventions for infants with Trisomy 18. We are trying to see if there are differences in what is considered acceptable interventions between the subspecialty groups. We are also asking if it agrees with counselling styles. Mentor confirmed. VICTR biostatistics voucher.

2020 November 04

Emily Deaton (Jessica Turnbull), Pediatric Critical Care

  • Previous clinic session 2020 May 13
  • I am expanding my previous project to the NICU (see previous clinic) and to other centers. NICU project is in data collectiom. Multicenter project is in design. Mentor confirmed. VICTR voucher request.

Madelyn Stevens (Alex Langerman), Otolaryngology

  • Investigate the relationship of patients with advanced stage head and neck cancer and palliative care. Planning for 1) retrospective chart review to clarify utilization of palliative care and outcomes and 2) Survey of providers (head and neck oncologists, radiation oncologists, surgeons) and patients attitudes and understanding of palliative care. Appreciate design and biostatistical input. Mentor confirmed. VICTR voucher request.

2020 October 28

Madelyn Stevens (Michael Topf), Otolaryngology

  • Time sensitive project evaluating treatment of head and neck cancer during covid and non-covid time. Hypothesis: Presence of covid pandemic resulted in more advanced stage disease. Retrospective chart review between Mar-June 2019 and Mar -June 2020 for patients presenting to a single tertiary academic center head and neck clinic. VICTR voucher request. Mentor confirmed.
    • Exposure variable: COVID Period: March-June 2019 vs March-June 2020
    • Variables of Interests: clinical volume by calendar month, type of visits (benign vs malignant), clinical staging and pathological staging, upstage (derived by comparing clinical staging and pathological staging), duration of symptoms (self-reported), referral related information
    • Descriptive statistics/tables/figures:
      • 2*2 table for clinical volume by type of visits and COVID period
      • dot plot for clinical volume by calendar month separately by COVID period (i.e. 2019 and 2020)
      • descriptive statistics table by COVID period for variables of interest
    • Hypothesis testing: We are more likely to observe upstage during COVID period
      • Outcome: Upstage (binary)
      • Exposure: COVID period
      • Interaction term: calendar month (4-level variable: Mar, Apr, May and June) * COVID
      • Adjusting variables: pre-specified patient demographic and clinical characteristics
      • Logistic regression will be performed with the interaciton between calendar month and COVID period of interest. The partial effect plot displaying relative odds for the interaction term (X-axis calendar month, grouped by COVID period) will be provided.
    • This is a good fit for VICTR voucher.

2020 October 21

Jan Niec (Muhammad Owais Ghani), Pediatric Surgery

  • Building a predictive model of clinical and CT radiographic features to predict Meckel’s diverticulum as a cause of small bowel obstruction in the child presenting with small bowel obstruction and no prior abdominal surgical history. We would like help in designing a control group of non-Meckel’s diverticulum small bowel obstruction. Mentor confirmed.

2020 September 30

Jeremy Joseph, Plastic Surgery

  • Discussed informally previously and a separate clinic has been set up with Dr. Higdon for the FitBit abdominoplasty study. This one is in patients undergoing breast reconstruction (DIEP) flap surgery and comparing patients getting reminders from the FitBit device vs those who do not to compare how long it takes them to return to their baseline # of steps. Abstract: The importance of physical activity and ambulation in prevention of post-operative complications is well-documented. However, strategies to encourage early ambulation is a field that continues to develop until these complications can be eliminated and improved patient outcomes are achieved. The use of actigraphy devices in the community has been used to track and promote individuals to be physically active. These devices are beginning to influence the medical field including investigations into outcomes in patients amongst various surgical specialties. In patients undergoing plastic surgery, though, the literature on actigraphy and its use in this population is sparse. A particularly susceptible population to post-operatively complications in plastic surgery, namely venous thromboembolism (VTE), are those undergoing breast reconstruction for breast cancer.12 A prior study performed by our group that utilized actigraphy to monitor patients undergoing deep inferior epigastric perforator (DIEP) flaps for reconstruction after breast cancer resection showed that this patient population does not return to their baseline ambulation status as far out as 8 weeks post-operatively. This proposed study is designed to expand on the previous work mentioned above in the DIEP flap patient population by examining the use of actigraphy devices in its role in promoting earlier return to baseline ambulation. A single-institution randomized control trial study design is proposed with patients undergoing DIEP flap reconstruction randomized into two groups of approximately 10-15 patients in each group (total of 20-30 patients). The control group will consist of DIEP flap patients who will wear a FitBit HR device for 2 weeks pre-operatively and 8 weeks post-operatively; this group’s devices will not provide any reminders or alerts. Rather, the use of the actigraphy device in this group would be solely for the purposes of monitoring activity levels. The experimental arm will consist of DIEP flap patients who will wear their FitBit HR device for the same duration and timepoints, but this group’s devices will provide alerts and reminders to stay active throughout their post-operative course. The data extracted from the monitoring of the devices from both groups of patients will be used to determine if the use of the alerts in this population shows promise in promoting return to baseline physical activity. If an improvement is identified in the experimental group as we hypothesize it will, it would suggest that the use of actigraphy devices may be beneficial in the post-operative course for this patient population. The impact of this could be multifold: reduction of post-operative complications, namely VTE, which in turn leads to improved individual patient outcomes, readmission rates, and a fiscal reprieve to the healthcare system due to the prevention of these complications. Mentor confirmed.
  • Dandan Liu and Wu Gong attend the clinic. Due to feasibility issues of recruitment, we suggest that the investigator use data from a prior study conducted a year ago the control arm and assign patients in the current study to intervention arm. Firstly, we should compare baseline characteristics between groups to check balance of the study and identify potential confounding variables. Secondly, we conduct univariate analysis to assess intervention effect on the outcome of interests (daily mean heart rate and daily steps count collected using Fitbit). Linear mixed effect model might be used with interaction between follow up days and intervention the term of interest. The scope of the study is appropriate for VICTR voucher.

2020 September 23

Jed Maslow, Orthopaedic Surgery

  • We are interested in evaluating the outcomes of revision radial head arthroplasty. The primary outcome of interest is overall survival (repeat surgery) of the implant. Secondary outcomes would include post-operative complications and functional outcomes (patient-reported). The comparative groups include primary radial head arthroplasty and those who undergo resection instead of replacement as a revision procedure. Mentor confirmed.

2020 September 16

Shiayin Yang, Otolaryngology

  • Background: The Nasal Obstruction Symptom Evaluation (NOSE) is a validated quality of life instrument used to assess the severity of nasal airway obstruction and how it affects a patient’s life. It asks patients to rate their feeling of nasal congestion and breathing over the past month. The score ranges from 0 to 100 with 0 as asymptomatic and 100 most symptomatic. It has been validated for use in measuring outcomes from septoplasty and rhinoplasty and is used by surgeons as guide to determine treatment options and improvement from surgery.1-2 Although this survey is routinely used in clinical practice, there is limited data regarding normative values, which limits interpretation of clinical procedures and surgeries. Study Objectives: The objective of this study is to determine normative values of NOSE score amongst the general population and asymptomatic individuals. VICTR voucher request.
  • Two objectives: (1) estimate the distribution of NOSE score; (2) evaluate the effect of age, sex, ethnicity, and location on NOSE score
  • NOSE score ranges from 0-100, with lower score indicating better outcome, therefore, expect to see right skewed distribution with more participants at lower end. There are several ways displaying the results: transformation to achieve normal distribution; describe proportion of patients falling within certain range; simply describe the whole distribution of the score
  • Sample size: International standard used N=120 to estimate reference range for clinical labs. From modelling aspect, rule of thumb is 15 per d.f. If want to see effects of certain clinical factors on NOSE score, for example, Y = age + sex + ethnicity (Caucasian, Black, Hispanic, Asian, other) + location (total 7 regions), need at least 12*15 participants. This study will have plenty cases to estimate NOSE score distribution as well as perform multiple linear regression.
  • Analysis: histogram, descriptive statistics, multivariable linear regression
  • The proposed work fits under the scope of VICTR biostatistics voucher.

2020 September 02

Alexander Langerman, Otolaryngology - Head and Neck Surgery

  • I’m preparing a grant to examine the association of surgical performance assessment (OSATS, SIMPL) with postoperative errors and complications for neck dissection. I wish to discuss a statistics plan for this. Ideally identify a biostatistics collaborator.
  • Dr Alexander Langerman is preparing a grant submission for evaluating the performance (competence) for a procedure of neck dissection. He intends to build a libary of annotated surgery videos for potential deep learning evaluation in future. The performance could be self-rated, cross-rated (by other attendings), and by third-party. The surgery has been conducted in Vanderbilt roughly 100 times a year. Chris asked the research significance and the practical significance, and suggested to have at least two third-party raters (observers), and inter-rater relibilities could be measured while the relationship between the rating and the clinical outcome could be explored. In addition, Chris suggested that the investigor to think about to establish a collaboration plan with the Department and the investigator happily agreed. Given the current COVID situation, the Biostatistics Department has been overwhelmed by a huge amount resource-demanding clinical researches. Therefore, VICTR would not have the capability to provide direct grant suppport for this effort before the grant submission deadline at the end of August. However, as a courtersy solution, Chris will donate several hours to support the statistical writing of the grant submission.

2020 August 26

Barron Frazier, Pediatric Emergency Medicine

  • The goal of our retrospective study utilizing de-identified data is to evaluate the post-intubation performance of a quaternary referral center that specializes in pediatric care. The study has these specific aims:
    • 1. Analyze the relationship between patient characteristics and post-intubation sedation
    • 2. Analyze pre-intubation interventions impact on post-intubation sedation
    • 3. Evaluate if difficult intubations impact post-intubation sedation
    • 4. Assess the impact of post-intubation sedation practices on duration of mechanical ventilation, duration of ICU level of care and overall hospitalization, and survivability.

Just started data collection and REDCap database has been built.

Outcome: appropriate post-intubation sedation, which is defined as whether the sedation is given to patients within suggested time frame (calculated using half life data of intubation meds). Timing depends on physician and physician make decision based on patient's condition and meds used. There are a lot of confounding issues. Predictors include long-acting paralytic used for RSI, presence of hypotension before intubation, time to disposition, presence of ED pharmacist, delayed PICU admission, age (better on continuous scale, instead of categorical), difficult intubation, intubations requring 2 more attempts, time of arrival, race, type of presentation, history of chronic condition, and neurology/neurosurgery consult.

Suggested group these predictors into categories. Check their correlations. Perform descriptive statistics. Then decide which predictors should be included in the model.

Patient outcomes include: mechanical ventilation days, ICU LOS, hospital LOS, and in-hospital mortality. Consider survival analysis or ordinal outcome analysis treating death as worst outcome (longest). If consider ordinal outcome using proportional odds model, the interpretation as odds ratio might be a little challeging. For mortality, if rate is low, the study may not have power to fit the model. Also need to consider what adjusting covariates should be included.

The scope of the analysis fits under VICTR voucher.

2020 August 19

Edward Qian, Pulmonary and Critical Care

  • Retrospective analysis of the SMART dataset looking at patients receiving empiric antibiotics. Specifically looking at the comparative effectiveness and renal/neurologic toxicity of cefepime vs piperacillin/tazobactam. Will come prepared with outcome of interest, exposure, and known confounders of interest. VICTR voucher request. Mentor confirmed.
  • The study aims to use retrospective data from the SMART trial to compare cefepime vs piperacillin/tazobactam in relation to MAKE30 and other secondary clinical outcomes. We need to firstly understand data availability/patterns of each antibiotic prescription which might be given multiple times during ED/ICU stays. Then we will assess indication bias of whether some patients might more likely be given one antibiotic vs the other. Propensity score or propensity score matching might be used if there is indication bias. The proposed work fits under the scope of VICTR voucher.

2020 August 12

Don Arnold, Pediatrics

  • IV Magnesium is recommended as a second-tier medication for acute asthma exacerbations in children. However, the evidence base for this comprises 5 RCT and a small aggregate sample size. More recent registry-level data suggests that IV Mg does not decrease hospitalizations. Our objective is to determine whether this treatment is associated with decreased hospitalizations and improved lung function in our prospective parent study of 933 children with acute exacerbations. We anticipate using propensity scores to test our hypothesis that Mg does not decrease hospitalizations or improve lung function in comparison with standard treatment without Mg. VICTR voucher request.

  • The study is looking at whether IV Magnesium is associated with the outcomes including; AAIRS score at 2hrs, hospitalization, time to Q 4-hr albuterol, and hospital LOS. We propose to perform propensity score matching in the analysis with matching covariates pre-defined. The proposed work fits under the scope of VICTR voucher.

2020 July 29

Emily Kight, Bioengineering

Previous clinic session 2020 July 08

  • 1. Feedback on validate panel test plan
  • 2. Test against 20-40 benign vs 20-40 disease age matched women
  • 3. Test against ELISA (more sensitive method but takes 8 hrs)
  • 4. Determine limit of detection
  • 5. Determine discriminatory power (how to do this?)

Leah Brown, Pulmonary/Critical Care

  • The aims of this study are twofold: 1)to assess the effect of gastric acid suppression (both before and during ICU admission) on lung colonization, injury, inflammation, and infection, and 2) to correlate respiratory culture data with incidence of these clinical outcomes. Understanding the dysbiotic consequences of gastric acid suppression on the lung microenvironment will help elucidate markers to predict negative outcomes and facilitate development of preventive interventions.

    • Hypothesis: In critically ill patients, gastric acid reducing agents facilitate the colonization of gut bacteria in the lungs, which may promote (or reflect)inflammation, injury (ARDS), and/or infection (pneumonia, sepsis).Enrichment of the lung microbiome with various gut bacteria may correlate with these clinical outcomes.
    • Likely multiple confounding variables– how to best control for these? General Assistance with statistical analysis for project.
    • VICTR Voucher, mentor confirmed

2020 July 08

Matthew Felbinger, Pharmacy/Emergency Medicine

  • I am working on evaluating the effects of a post-intubation sedation protocol for patients that have an endotracheal tube placed in the emergency department and require analgesics/sedatives after tube placement, to maintain comfort with the breathing tube. In short, the protocol directs physicians to select two medications (propofol and fentanyl) and avoid the use of other sedatives (i.e. benzodiazepines). The questions that I’d like to address are:

    • 1. What is the compliance with the protocol? The presumption is that the compliance is high, but deviations are likely. This is mostly QI focused.
    • 2. Does the use of the protocol reduce the amount of benzodiazepines used in the ED for these patients? We hypothesize that the protocol will decrease use of benzodiazepines.
    • 3. If there is a reduction in benzodiazepine use in the ED, does this have an impact on Delirium and coma-free days in the ICU? This is based on the presumption that patients receive the same standard of care once in the ICU, so the only “intervention” would be medications administered in the ED. I’d need help with matching patients and adjusting for covariates to best represent the data to answer this question.
    • Interrupted time series analysis : adjusted proportion of Benzo use vs. time, expect to see a overall decrease with a big jump around when intervention happens
    • Interrupted time series analysis : proportion of protocol follows vs. time
    • Association between protocol implement with clinical outcomes: does medication regimen associate with outcomes? See what have been done in ED changes what have been done in ICU. Need to consider outcome and other factors that may modify/moderate/confound the outcome as well as baseline clinical factors.
    • VICTR voucher.

Emily Kight, Bioengineering

  • I am working on an early detection panel of biomarker test for ovarian cancer in urine using affordable and low-cost lateral flow assay (LFA) technology. In this order, I plan to: Test the ability to discriminate between benign vs disease state for age matched women, Compare panel test to ELISA (validate same urine samples to ensure ELISA results are the same as LFA results), Test predictive power of panel test in clinical cohort of women with a benign cyst. Determine PPV.
    • For #1, how many of each type do I need to say my test can discriminate?
    • For #2, is it enough to be just as good as ELISA which is longer and more expensive? How do I determine the uncertainty in my measurement?
    • #3 How many times does my test have to be right to be considered predictive? How many women do I need to do predictive testing? Can my panel test be combined with algorithm of patient info to increase PPV? I’d like to compare standard of care vs (standard of care+panel test) vs. (standard of care+panel test+algorithm)
  • Literature research on all biomarkers that were used for decision making and cost of the biomarkers. Pick some most commonly used (i.e. 5) and see whether they can discriminate the disease.
  • Can LFA measure the biomarkers? Need to make sure the biomarkers chosen are clinically meaningful and make biological sense. Use Bland-Altman plot to assess agreement between biomarker measured by LFA and measured by ELISA.

2020 June 24

Claci Walls, Pediatric Emergency Medicine

  • We have implemented a curriculum to help improve pediatric airway management and would like to review some of our pre and post survey data. We would like to discuss with the statisticians the best way to analyze this type of data and what would be the appropriate analysis to answer our question if this curriculum improve resident involvement in airway distress situations and if this increased the number of airway procedures.

Whitney Gannon, Pulmonary and critical care medicine

  • We performed a randomized controlled trial of different educational methods in teaching ECMO to clinicians. We would like direction on the best way to compare groups and how to address missingness.

2020 June 10

Kimberley Harper, Pediatric Critical Care

  • I have implemented a risk stratified sedation weaning protocol and wish to look at outcomes and differences pre and post protocol. VICTR biostatistics voucher. Mentor confirmed.
  • Hypothesis: implementation of sedation weaning protocol based on risk strarification will reduce (1) weaning duration (in days, ranges from 1 to 50 days, majority is between 10 to 20 days), (2) ICU length of stay.
  • Pre period is from 2019 June to December, post period from December to March 2020.
  • Suggest interrupted time series analysis to see whether the difference is just due to time effect or due to treatment.
  • Outcome ~ time (since day zero) + period (pre/post) + time * period + covariates (duration of sedation,...)
  • The scope of the project falls under VICTR biostat voucher.

Caroline Erickson, School of Medicine

  • The project is a cost analysis of the MIND-USA clinical trial and the research question is: Does treating ICU delirium with haloperidol or ziprasidone affect total ICU costs relative to placebo in adult medical or surgical ICU patients? Questions to address are related to the statistical plan and obtaining a VICTR grant.VICTR biostatistics voucher. Mentor confirmed.
  • Compare ICU costs beween two groups. Cost is usually skewed and traditional parametric model is not desired. Suggest use Cox proportional hazards model (replacing time with cost and all has event).
  • It is better to analyze both ICU cost and total hospital utilization in case of cost shiftting. There is no itemized individual cost, but cost buckets. Can compare overall cost and cost within bucket. Show cost curve (survival curve) instead of reporting median. If cost shiftting only occurs in sever pts, median cost will not show any difference.
  • Competing risks of death, which in this study is the worst outcome.
  • Daily cost ~ daily delirium + daily sepsis. Reference paper on analyzing daily cost:
  • The scope of the project falls under VICTR biostat voucher.

2020 May 13

Emily Deaton, Pediatric Critical Care

  • Estimate on biostats services, advice for appropriate statistical analysis for my fellowship scholarly project. Evaluating moral distress in those working within the health care team in the pediatric ICU and pediatric cardiac ICU. Comparing the level of moral distress to the perceived ethical decision making climate found within the unit. Within these goals, we are also evaluating whether knowledge or use of the ethics consult service is a protective factor. VICTR biostatistics voucher. Mentor confirmed.
  • Survey on Moral distress in PICU. Total 53 items, calculated score for each item will be added to get total score. Need to consider if some items are missing.
  • Collection of survey started from end of February and will be completed in June. Covariate of COVID?
  • Challenge: religious beliefs
  • Question: does having experience wih consult service decrease moral distress or increase perception of the ethical decision making climate questionnaire. Can fit a model with moral distress as outcome and decision making climate, ethics consult service as predictors.
  • Total enrolled N=75 (38 nursers, 9 faculty, 4 fellows, 11 peds residents, 2 EM residents, 5 therapists, 4 NP/PA). Descriptive statistics of all item scores overall and by groups.
  • The scope of the work fits under VICTR biostat voucher of $5000.

Cindy Hernandez, Urology

  • Reduction of Allogenic Blood Transfusion in Locally Advanced Kidney Cancer. PI: Moses. Additional Study Authors: Hernandez, Dawes/Siegrest, Benson, Idrees, Garrard, Balsara. Background and Rationale: Allogenic blood transfusion is associated with adverse events such as pulmonary and vascular complications, immunosuppression, and cancer recurrence/specific survival. Radical nephrectomy for large tumors (>7cm) and/or tumor thrombi are complex and frequently require allogenic blood transfusions due to acute blood loss from parasitic vessels and thrombectomy with or without IVC reconstruction. There are specific techniques that can be utilized to reduce the need for allogenic blood transfusion, including acute normovolemic hemodilution (ANH), cell saver, and veno-venous (VV) bypass. The utilization of these techniques has not been well described in kidney cancer, highlighting an unmet need in patient care. Hypothesis: Utilization of blood sparing techniques in locally advanced kidney cancer can reduce allogenic blood transfusion. Protocol: Randomization of patients with >=cT2 renal masses to blood sparing vs non-blood sparing intra-operative techniques. Determination of method of blood sparing to be determined based on patient and tumor characteristics. Primary Endpoint: Reduction in allogenic blood transfusion. Secondary Endpoints: Complications (measured by Charlson or Elixhauser), Cancer Recurrence, 3-year Overall Survival, Cost. Exploratory Endpoints: Assessment of circulating tumor cells (CTCs) in preoperative blood specimen, pre- and post-wash cell saver container, and postoperative blood specimen; Measurement of pre- and post-operative inflammatory markers (CRP). Sample size: To be determined by calculating the % of patients receiving allogenic blood transfusion in a contemporary VUMC cohort, as well as from known literature. We will aim for a 20%/30%/50% reduction in number of units of allogenic blood, which will allow for calculation of a two-sided alpha of 0.05, indicating a significant reduction. Patients will be randomized 1:1, patient (and surgeon?) will be blinded to the study arm. Postoperative blood transfusion will be included in the final tally for each patient. Inclusion: Patients 18 and older with reasonable hepatic, pulmonary, renal and cardiac function, who have >=cT2 renal masses, Hemoglobin >=9 or 10, able to provide consent, can have N1 or M1 disease if they are deemed surgical candidates (including cytoreductive nephrectomy). Exclusion: severe anemia. Questions to address: power analysis for determination of sample size. Is randomization method appropriate? VICTR biostatistics voucher. Mentor confirmed.
  • VUMC 12/17/2015 to 12/17/2019, total 446 Nephrectoies (partial and radical), among those, 158 Nephrectomies >= cT2 Renal Cell Carcinoma ( 20.8% (33) transfused, 14.5% (23) IVC thrombectomy). The eligible cohort is from 158, which is around 140. Randomize the 140 patients into two groups: receive blood sparing techniques vs. standard care.
  • Primary outcome: transfusion units received (those not transfused will have number as zero)
  • Proportional odds model can be used to evaluate the difference of units transfused between groups
  • Suggest consult with cancer center for sample size and randomization

2020 May 06

Seth Davis, Otolaryngology

  • Large defects in the oral cavity often require vascularized free tissue transfer for reconstruction. These “free flaps” can atrophy over time, leading to functional deficits. We attempt to quantify this degree of atrophy over time via volumetric measurements of CT scans. We are hoping to perform a power analysis based on prelim data to determine the number of patients needed to generate significance between findings in radiated and non-radiated patients. Mentor confirmed.
  • Two volumetric measurements per patient, approximately at 3 months and 1 year, but not fixed for all patients. Baseline volume is not available and is currently estimated using the fitted slope and BMI. Fairly rapid change during first few months is expected, and the curve should be flattened approaching 1 year. Therefore, two time points is not enough to provide accurate estimate of the overall trend. We suggest obtain more data points as well as more patients.
  • Can fit a mixed-effects model of all follow up volume as the outcome, the fixed effects include baseline volume, time by radiation interaction.

2020 April 22

Jo Ellen Wilson, Psychiatry/Center for Critical Illness Brain Dysfunction and Survivorship

  • I would like guidance regarding a stats plan for a CAM-ICU validation project (validated in a new population) - neurocritically ill. Multiple assessments (1 each day) per patient. Reference rater collected DSM-5 level data in a standardized form. Would like assistance with analysis plan. VICTR Biostatistics voucher. Mentor confirmed.
  • Validated tool for delirium diagnosis called VADA (as measured by DSM5), aim to validate VADA in neuro critically ill patients.
  • VADA was collected once a day (if there is), CAM was collected twice a day. VADA will be paired to the closest CAM on that day.
  • There will be multiple pairs of delirium (Y/N) per patient. The agreement between the two will be measured and presented as PPV/NPV (or sensitivity/specificity).
  • The scope of the analysis fits under a standard VICTR biostat voucher.

Whitney Gannon, Pulmonary/Critical Care

  • Retrospective cohort analysis of anticoagulation practices in extracorporeal membrane oxygenation. We will examine bleeding complications among usual anticoagulation practices in patients receiving venovenous ECMO. Independent investigator.
  • Patients on ECMO often need blood thinner to prevent clotting, however, it may cause bleeding.
  • Inclusion: patients on ECMO and with no bleeding disorder, no clotting disorder, no recent surgery (so they are on blood thinner only due to use of ECMO)
  • Goal: Whether composite bleeding/clotting is associated with in-hospital death.
  • Enrolled patients from 2016 until now, total N=54 patients. 14 out of 54 died in hospital. 22 had bleeding events. 7 clotting events.
  • Ideal if enough sample: time-varying covariate Cox model of time to death with bleeding and clotting events as two time-varying covariates. However, with this limited events (N=14), we suggested perform simple descriptive statistics.
  • Mediation analysis: indicator of bleeding, clotting, their interaction, and disease severity. Need about 60-90 events.

2020 April 8

Kristina Betters, Pediatrics/Critical Care

  • We are evaluating a novel scoring system to observe improvements in patients strength during a PICU stay. VICTR voucher request, independent investigator.
  • The goal of the project is to evaluate whether PAM score is sensitive to clinical interventions. The analysis will include: (1) Table 1 descriptive statistics of patients characteristics; (2) evaluate association between PAM score and physical functional scale; (3) compare PAM score by discharge disposition; (4) fit a linear model (or proportional odds model) of PAM score at discharge in association with other clinical measures adjusting for initial PAM score.
  • The scope of the analysis fits VICTR biostatistics voucher

2020 March 11

Jaycelyn Holland, Pediatric Emergency Medicine

  • There are multiple scoring systems for assessment of leadership or ‘non-technical’ skills in crisis scenarios, though none have been studied in a medical student population. We hope to perform an initial evaluation of a BARS (behaviorally anchored rating scale) to determine if it shows good inter-rater reliability in a medical student population. I am hoping to ensure we have an appropriate plan for video review to obtain scores for analysis. I would also appreciate advice on how data can be analyzed (once obtained) to produce educationally relevant data. VICTR voucher request, mentor confirmed.

Monica Bhanot, Dept of Diabetes, Endocrinology, & Metabolism

  • We are analyzing human adipose tissue depots (SQ vs omental) for iron containing macrophages to correlate their differential number with insulin resistance. VICTR voucher request, mentor confirmed.

2020 February 19

Jonathan Siktberg, Unknown

  • Please provide a short description of your project and the questions you’d like to address: Our project is a case series of 653 patients who have been treated for age-related macular degeneration under the step therapy protocol at VEI. We have completed data collection and would like guidance on our data analysis, specifically on the utility of multiple linear regression in our project. Mentor confirmed.

2020 February 12

Melanie Whitmore, Pharmacy

  • My project will analyze the utilization of chemical restraints in agitated patients. We are looking at the association of chemical restraint administration and length of hospital stay, associations with gender, time of year, etc. Would like to review use of statistical tests for appropriateness and analysis.

Belinda Li, Pediatric urology

  • A retrospective review of a combination of clinical data (10 parameters) to determine predictors or patterns in the type of surgery they receive. Mentor confirmed.

2020 February 5

Belinda Li, Pediatric Urology

  • A retrospective review of a combination of clinical data (10 parameters) to determine predictors or patterns in the type of surgery they receive.

Christine Lopez, Internal Medicine/Hepatology

  • Retrospective study which will involve evaluation of changes in liver tests in women with NAFLD over the course of pregnancy and post-partum. We hypothesize there may be a worsening in liver tests during pregnancy. We have applied for a VICTR voucher and need to lay out a more detailed plan for statistical analysis before it can be reviewed.

2020 January 22

Melanie Whitmore, Pharmacy

  • My project will analyze the utilization of chemical restraints in agitated patients. We are looking at the association of chemical restraint administration and length of hospital stay, associations with gender, time of year, etc. Clarification and interpretation of statistical tests run on SPSS.

Samantha Brokenshire, Pharmacy

  • Retrospective, pre-post study evaluating change in diuretic needs, serum potassium and urine output after initiation of spironolactone. Would like assistance in JMP Matched Pair analyses and review of statistical methods. Mentor confirmed.

2020 January 8

Laura Shashy, Pediatrics- Neonatology

  • Fellowship project- pre and post intervention data. Review statistical analysis. Has attended Thursday clinic.
  • VICTR voucher (no biostat)/Mentor confirmed

Melanie Whitmore, Pharmacy

  • I would like to request an appointment with Dr. Chris Lindsell, as he is familiar with my project and has advised me in a previous clinic appointment. My project will analyze the utilization of chemical restraints in agitated patients. We are looking at the association of chemical restraint administration and length of hospital stay, associations with gender, time of year, etc. I have sent a more thorough description via email to Dr. Lindsell. Thanks!
Topic revision: r2 - 27 Apr 2021, DandanLiu

This site is powered by FoswikiCopyright © 2013-2022 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding Vanderbilt Biostatistics Wiki? Send feedback