Long-term cognitive outcomes after surgery and anesthesia: what we find depends on where we look.

Purpose of review: To review how anecdote and narrative medicine, primary cohort studies, epidemiological studies, and the dementia literature can be bridged to understand long-term postoperative cognitive decline. Recent findings: Primary cohort studies have measured recoverable declines in memory and executive function after major surgery, but less-appreciated sources also offer critical insights. Anecdote reveals that functionally-impactful cognitive decline may persist after physical recovery in some patients despite modern medications and monitoring, and that physicians are unprepared to address patients' cognitive concerns. However, epidemiological studies reproducibly demonstrate that elective surgery has no, or a negligible, average impact on cognition in older patients. Cognitively provocative factors - like medical hospital admissions or health factors like diabetes and smoking - are common in late life, and surgery likely contributes minimally to long-term cognitive change for most patients. Summary: Patients should be reassured that, while anecdotes of durable cognitive change after surgery are easily accessible, most patients experience cognitive recovery after major surgery. However, those who do not recover deserve characterization of their symptoms and investigation of modifiable causes to facilitate cognitive recovery.

Perioperative Considerations in Older Kidney and Liver Transplant Recipients: A Review.

With the growth of the older adult population, the number of older adults waitlisted for and undergoing kidney and liver transplantation has increased. Transplantation is an important and definitive treatment for this population. We present a contemporary review of the unique preoperative, intraoperative, and postoperative issues that patients older than 65 y face when they undergo kidney or liver transplantation. We focus on geriatric syndromes that are common in older patients listed for kidney or liver transplantation including frailty, sarcopenia, and cognitive dysfunction; discuss important considerations for older transplant recipients, which may impact preoperative risk stratification; and describe unique challenges in intraoperative and postoperative management for older patients. Intraoperative challenges in the older adult include using evidence-based best anesthetic practices, maintaining adequate perfusion pressure, and using minimally invasive surgical techniques. Postoperative concerns include controlling acute postoperative pain; preventing cardiovascular complications and delirium; optimizing immunosuppression; preventing perioperative kidney injury; and avoiding nephrotoxicity and rehabilitation. Future studies are needed throughout the perioperative period to identify interventions that will improve patients' preoperative physiologic status, prevent postoperative medical complications, and improve medical and patient-centered outcomes in this vulnerable patient population.

Gaps in cognitive care among older patients undergoing spine surgery.

INTRODUCTION: Among older adults undergoing surgery, postoperative delirium is the most common complication. Cognitive impairment and dementia are major risk factors for postoperative delirium, yet they are frequently under-recognized. It is well established that applying delirium preventive interventions to at-risk individuals can reduce the likelihood of delirium by up to 40%. The aim of this study was to evaluate how often delirium preventive interventions are missing in patients at risk for delirium due to baseline cognitive impairment. METHODS: We conducted a retrospective study using data from the observational study Perioperative Anesthesia Neurocognitive Disorder Assessment-Geriatric (PANDA-G) and clinical data from the University of California San Francisco delirium prevention bundle. Patients age 65+ received preoperative multidomain cognitive assessment as part of a research protocol prior to undergoing inpatient spine surgery at a single major academic institution. Results of the cognitive testing were not available to clinical teams. Using electronic medical records, we evaluated if patients who were cognitively impaired at baseline received delirium prevention orders, sleep orders, and avoidance of AGS Beers Criteria® potentially inappropriate medications. RESULTS: Of the 245 patients included in the study, 42% were women. The mean [SD] age was 72 [5.2] years. Preoperative cognitive impairment was identified in 40% of participants (N = 98), and of these, 34% had postoperative delirium. Of patients with preoperative cognitive impairment, 45% did not receive delirium preventive orders, 43% received PIMs, and 49% were missing sleep orders. At least one of the three delirium preventive interventions was missing in 70% of the patients. DISCUSSION: Undiagnosed preoperative cognitive impairment among older adults undergoing spine surgery is common. When cognitive test results were not available to clinicians, patients with baseline cognitive impairment frequently did not receive evidence-based delirium preventive interventions. These findings highlight an opportunity to improve perioperative brain health care via preoperative cognitive assessment and clinical communication.

Long-term cognitive outcome after elective hip or knee total joint arthroplasty: A population-based observational study.

BACKGROUND: One year after elective hip or knee total joint arthroplasty (TJA), >30% of older adults meet criteria for postoperative neurocognitive disorder. However, this is not contextualized with long-term cognitive outcomes in comparable surgical and nonsurgical controls. We analyzed population-based data to compare long-term cognitive outcomes in older adults after TJA, other surgeries, and with and without arthritis pain. METHODS: This was a retrospective observational analysis of United States older adults in the Health and Retirement Study (HRS) who underwent elective TJA, or elective surgery without expected functional benefits (e.g., cholecystectomy; inguinal herniorrhaphy), between 1998 and 2018 at aged 65 or older. TJA recipients were also age- and sex-matched to nonsurgical controls who reported moderate-severe arthritic pain or denied pain, so that comparison groups included surgical and nonsurgical (pain-suffering and pain-free) controls. We modeled biennially-assessed memory performance, a measure of direct and proxy cognitive assessments, before and after surgery, normalized to the rate of memory decline ("cognitive aging") in controls to express effect size estimates as excess, or fewer, months of memory decline. We used linear mixed effects models adjusted for preoperative health and demographic factors, including frailty, flexibly capturing time before/after surgery (knots at -4, 0, 8 years; discontinuity at surgery). RESULTS: There were 1947 TJA recipients (average age 74; 63% women; 1358 knee, 589 hip) and 1631 surgical controls (average age 76; 38% women). Memory decline 3 years after TJA was similar to surgical controls (5.2 [95% confidence interval, CI -1.2 to 11.5] months less memory decline in the TJA group, p = 0.11) and nonsurgical controls. At 5 years, TJA recipients experienced 5.0 [95% CI -0.9 to 10.9] months less memory decline than arthritic pain nonsurgical controls. CONCLUSION: There is no systematic accelerated memory decline at 3 years after TJA compared with surgical or nonsurgical controls.

Association of neurocognitive disorders with morbidity and mortality in older adults undergoing major surgery in the USA: a retrospective, population-based, cohort study.

BACKGROUND: Neurocognitive disorders become increasingly common as patients age, and increasing numbers of surgical interventions are done on older patients. The aim of this study was to understand the clinical characteristics and outcomes of surgical patients with neurocognitive disorders in the USA in order to guide future targeted interventions for better care. METHODS: This retrospective cohort study used claims data for US Medicare beneficiaries aged 65 years and older with a record of inpatient admission for a major diagnostic or therapeutic surgical procedure between Jan 1, 2017, and Dec 31, 2018. Data were retrieved through a data use agreement between Dartmouth Hitchcock Medical Center and US Centers for Medicare and Medicaid Services via the Research Data Assistance Center. The exposure of interest was the presence of a pre-existing neurocognitive disorder as defined by diagnostic code within 3 years of index hospital admission. The primary outcome was mortality at 30 days, 90 days, and 365 days from date of surgery among all patients with available data. FINDINGS: Among 5 263 264 Medicare patients who underwent a major surgical procedure, 767 830 (14·59%) had a pre-existing neurocognitive disorder and 4 495 434 (85·41%) had no pre-existing neurocognitive disorder. Adjusting for demographic factors and comorbidities, patients with a neurocognitive disorder had higher 30-day (hazard ratio 1·24 [95% CI 1·23-1·25]; p<0·0001), 90-day (1·25 [1·24-1·26]; p<0·0001), and 365-day mortality (1·25 [1·25-1·26]; p<0·0001) compared with patients without a neurocognitive disorder. INTERPRETATION: Our findings suggest that the presence of a neurocognitive disorder is independently associated with an increased risk of mortality. Identification of a neurocognitive disorder before surgery can help clinicians to better disclose risks and plan for patient care after hospital discharge. FUNDING: Department of Anesthesiology and Perioperative Medicine at Dartmouth Hitchcock Medical Center.

'It was a great brain, and I miss it': lay perspectives on postoperative cognitive dysfunction.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is a concern after anaesthesia and surgery, but preoperative discussion of neurocognitive risks with older patients rarely occurs. Anecdotal experiences of POCD are common in the popular media and may inform patient perspectives. However, the degree of alignment between lay and scientific perspectives on POCD is not known. METHODS: We performed inductive qualitative thematic analysis on website user comments publicly submitted under an article entitled, 'The hidden long-term risks of surgery: "It gives people's brains a hard time"', published by the UK-based news source The Guardian in April 2022. RESULTS: We analysed 84 comments from 67 unique users. Themes that emerged from user comments included the importance of functional impact ('Couldn't work … even reading was a struggle'), attribution to a range of causes but particularly the use of general, rather than consciousness-preserving, anaesthesia techniques ('side effects aren't fully understood'), and inadequate preparation and response by healthcare providers ('I would have benefited by being warned'). CONCLUSIONS: There is misalignment between professional and lay understandings of POCD. Lay people emphasise subjective and functional impact of symptoms, and express beliefs about the role of anaesthetics in causing POCD. Some patients and caregivers affected by POCD report feeling abandoned by medical providers. In 2018, new nomenclature for postoperative neurocognitive disorders was published, which better aligns with lay perspectives by including subjective complaints and functional decline. Further studies based on newer definitions and public messaging may improve concordance between different understandings of this postoperative syndrome.

Intraoperative Use of Albumin in Major Noncardiac Surgery: Incidence, Variability, and Association With Outcomes.

BACKGROUND: The impact of albumin use during major surgery is unknown, and a dearth of evidence governing its use in major noncardiac surgery has long precluded its standardization in clinical guidelines. OBJECTIVE: In this study, we investigate institutional variation in albumin use among medical centers in the United States during major noncardiac surgery and explore the association of intraoperative albumin administration with important postoperative outcomes. METHODS: The study is an observational retrospective cohort analysis performed among 54 U.S. hospitals in the Multicenter Perioperative Outcomes Group and includes adult patients who underwent major noncardiac surgery under general anesthesia between January 2014 and June 2020. The primary endpoint was the incidence of albumin administration. Secondary endpoints are acute kidney injury (AKI), net-positive fluid balance, pulmonary complications, and 30-day mortality. Albumin-exposed and albumin-unexposed cases were compared within a propensity score-matched cohort to evaluate associations of albumin use with outcomes. RESULTS: Among 614,215 major surgeries, predominantly iso-oncotic albumin was administered in 15.3% of cases and featured significant inter-institutional variability in use patterns. Cases receiving intraoperative albumin involved patients of higher American Society of Anesthesiologists physical status and featured larger infused crystalloid volumes, greater blood loss, and vasopressor use. Overall, albumin was most often administered at high-volume surgery centers with academic affiliation, and within a propensity score-matched cohort (n=153,218), the use of albumin was associated with AKI (aOR 1.24, 95% CI 1.20-1.28, P <0.001), severe AKI (aOR 1.45, 95% CI 1.34-1.56, P <0.001), net-positive fluid balance (aOR 1.18, 95% CI 1.16-1.20, P <0.001), pulmonary complications (aOR 1.56, 95% CI 1.30-1.86, P <0.001), and 30-day all-cause mortality (aOR 1.37, 95% CI 1.26-1.49, P <0.001). CONCLUSIONS: Intravenous albumin is commonly administered among noncardiac surgeries with significant inter-institutional variability in use in the United States. Albumin administration was associated with an increased risk of postoperative complications.

Cardiac surgery, ICU sedation, and delirium: is dexmedetomidine the silver bullet?

PURPOSE OF REVIEW: Delirium is a marker of acute brain insufficiency and a harbinger of poor outcomes and increased healthcare costs. Despite success preventing delirium by nonpharmacologic measures, the incidence in the postcardiac surgical ICU population remains high. Dexmedetomidine, a selective alpha-2 agonist, is a plausible preventive agent with sedative, anxiolytic, analgesic, sympatholytic and anti-inflammatory properties, and is the subject of very active study in cardiac surgery populations. RECENT FINDINGS: Recent trials, including DEXACET (2019), DECADE (2020), LOWDEXDEL (2021), and DIRECT (2022) individually, failed to show a benefit for dexmedetomidine and highlighted associated risks. Meta-analyses have offered conflicting results, highlighting the complexity of delirium, and likely interaction of multiple etiological pathways; those that concluded benefit often were driven by trials at high risk of bias. Meta-analyses excluding biased trials currently suggest no benefit for dexmedetomidine over control in unselected cardiac surgical populations. SUMMARY: Although using dexmedetomidine to prevent delirium in unselected cardiac surgical patients is not supported by current evidence, there remains hope that it may offer benefits in highly selected populations, and further trials are ongoing.

Impact of persistent pain on function, cognition, and well-being of older adults.

BACKGROUND: We sought to determine the population-level associations between persistent pain and subsequent changes in physical function, cognitive function, and well-being, outcomes important to older adults. METHODS: We used data from National Health Aging Trends Study (NHATS) of community-dwelling Medicare beneficiaries age 65+ from 2011 to 2019. We defined "persistent pain" as being bothered by pain in the last month in both the 2011and 2012 interviews and "intermittent" pain including those reporting bothersome pain in one interview only. We used competing risks regression to estimate the association between persistent pain and the development of clinically meaningful declines in physical function, cognitive function, and well-being, adjusting for age, sex, race, education, and marital status at baseline. RESULTS: Of the 5589 eligible NHATS participants, 38.7% reported persistent pain and 27.8% reported intermittent pain. Over one-third described pain in five or more sites. Over the subsequent 7 years, participants with persistent pain were more likely to experience declines in physical function (64% persistent pain, 59% intermittent pain, 57% no bothersome pain; aHR 1.14, 95% CI 1.05-1.23) and well-being (48% persistent pain, 45% intermittent pain, 44% no bothersome pain; aHR 1.11, 95% CI 1.01-1.21), but were not more likely to experience cognitive decline (25% persistent pain, 24% intermittent pain, 23% no bothersome pain; aHR 1.02, 95% CI 0.90-1.16). CONCLUSIONS: Persistent pain is common in older adults and occurs in multiple body sites. Persistent pain contributes to meaningful declines in physical function and well-being over 7 years and warrants proactive interventions to mitigate pain.

Preoperative Factors Predict Memory Decline After Coronary Artery Bypass Grafting or Percutaneous Coronary Intervention in an Epidemiological Cohort of Older Adults.

Background Durable memory decline may occur in older adults after surgical (coronary artery bypass grafting [CABG]) or nonsurgical (percutaneous coronary intervention) coronary revascularization. However, it is unknown whether individual memory risk can be predicted. We reanalyzed an epidemiological cohort of older adults to predict memory decline at ≈1 year after revascularization. Methods and Results We studied Health and Retirement Study participants who underwent CABG or percutaneous coronary intervention at age ≥65 years between 1998 and 2015 and participated in ≥1 biennial postprocedure assessment. Using a memory score based on direct and proxy cognitive tests, we identified participants whose actual postprocedure memory score was 1-2 ("mild") or >2 ("major") SDs below expected postprocedure performance. We modeled probability of memory decline using logistic regression on preoperatively known factors and evaluated model discrimination and calibration. A total of 1390 participants (551 CABG, 839 percutaneous coronary intervention) underwent CABG/percutaneous coronary intervention at 75±6 years old; 40% were women. The cohort was 83% non-Hispanic White, 8.4% non-Hispanic Black, 6.4% Hispanic ethnicity, and 1.7% from other groups masked by the HRS (Health and Retirement Study) to preserve participant confidentiality. At a median of 1.1 (interquartile range, 0.6-1.6) years after procedure, 267 (19%) had mild memory decline and 88 (6.3%) had major memory decline. Factors predicting memory decline included older age, frailty, and off-pump CABG; obesity was protective. The optimism-corrected area under the receiver operator characteristic curve was 0.73 (95% CI, 0.71-0.77). A cutoff of 50% probability of memory decline identified 14% of the cohort as high risk, and was 94% specific and 30% sensitive for late memory decline. Conclusions Preoperative factors can be used to predict late memory decline after coronary revascularization in an epidemiological cohort with high specificity.

A novel approach for the detection of cognitive impairment and delirium risk in older patients undergoing spine surgery.

BACKGROUND: Postoperative delirium is a common postsurgical complication in older patients and is associated with high morbidity and mortality. The objective of this study was to determine whether a digital cognitive assessment and patient characteristics could identify those at-risk. METHODS: Patients 65 years and older undergoing spine surgeries ≥3 h were evaluated as part of a single-center prospective observational cohort study at an academic medical center, from January 1, 2019, to December 31, 2020. Of 220 eligible patients, 161 were enrolled and 152 completed the study. The primary outcome of postoperative delirium was measured by the Confusion Assessment Method for the Intensive Care Unit or the Nursing Delirium Screening Scale, administered by trained nursing staff independent from the study protocol. Baseline cognitive impairment was identified using the tablet-based TabCAT Brain Health Assessment. RESULTS: Of the 152 patients included in this study, 46% were women. The mean [SD] age was 72 [5.4] years. Baseline cognitive impairment was identified in 38% of participants, and 26% had postoperative delirium. In multivariable analysis, impaired Brain Health Assessment Cognitive Score (OR 2.45; 95% CI, 1.05-5.67; p = 0.037), depression (OR 4.54; 95% CI, 1.73-11.89; p = 0.002), and higher surgical complexity Tier 4 (OR 5.88; 95% CI, 1.55-22.26; p = 0.009) were associated with postoperative delirium. The multivariate model was 72% accurate for predicting postoperative delirium, compared to 45% for the electronic medical record-based risk stratification model currently in use. CONCLUSION: In this prospective cohort study of spine surgery patients, age, cognitive impairment, depression, and surgical complexity identified patients at high risk for postoperative delirium. Integration of scalable digital assessments into preoperative workflows could identify high-risk patients, automate decision support for timely interventions that can improve patient outcomes and lower hospital costs, and provide a baseline cognitive assessment to monitor for postoperative cognitive change.

Development and External Validation of a Mortality Prediction Model for Community-Dwelling Older Adults With Dementia.

Importance: Estimating mortality risk in older adults with dementia is important for guiding decisions such as cancer screening, treatment of new and chronic medical conditions, and advance care planning. Objective: To develop and externally validate a mortality prediction model in community-dwelling older adults with dementia. Design, Setting, and Participants: This cohort study included community-dwelling participants (aged ≥65 years) in the Health and Retirement Study (HRS) from 1998 to 2016 (derivation cohort) and National Health and Aging Trends Study (NHATS) from 2011 to 2019 (validation cohort). Exposures: Candidate predictors included demographics, behavioral/health factors, functional measures (eg, activities of daily living [ADL] and instrumental activities of daily living [IADL]), and chronic conditions. Main Outcomes and Measures: The primary outcome was time to all-cause death. We used Cox proportional hazards regression with backward selection and multiple imputation for model development. Model performance was assessed by discrimination (integrated area under the receiver operating characteristic curve [iAUC]) and calibration (plots of predicted and observed mortality). Results: Of 4267 participants with probable dementia in HRS, the mean (SD) age was 82.2 (7.6) years, 2930 (survey-weighted 69.4%) were female, and 785 (survey-weighted 12.1%) identified as Black. Median (IQR) follow-up time was 3.9 (2.0-6.8) years, and 3466 (81.2%) participants died by end of follow-up. The final model included age, sex, body mass index, smoking status, ADL dependency count, IADL difficulty count, difficulty walking several blocks, participation in vigorous physical activity, and chronic conditions (cancer, heart disease, diabetes, lung disease). The optimism-corrected iAUC after bootstrap internal validation was 0.76 (95% CI, 0.75-0.76) with time-specific AUC of 0.73 (95% CI, 0.70-0.75) at 1 year, 0.75 (95% CI, 0.73-0.77) at 5 years, and 0.84 (95% CI, 0.82-0.85) at 10 years. On external validation in NHATS (n = 2404), AUC was 0.73 (95% CI, 0.70-0.76) at 1 year and 0.74 (95% CI, 0.71-0.76) at 5 years. Calibration plots suggested good calibration across the range of predicted risk from 1 to 10 years. Conclusions and Relevance: We developed and externally validated a mortality prediction model in community-dwelling older adults with dementia that showed good discrimination and calibration. The mortality risk estimates may help guide discussions regarding treatment decisions and advance care planning.

Evaluation of Telephone-Based Cardiac Rehabilitation Services Delivered to Adults 65 and Older During the Early Months of the COVID-19 Pandemic.

This study was performed to evaluate the effectiveness of a hybrid, telephone-based cardiac rehabilitation (TBCR) program implemented early in the COVID-19 pandemic compared with in-person, center-based programming offered prior to the pandemic. The focus was on older adults' engagement and outcomes. Matched groups of hybrid and in-person cardiac rehabilitation (CR) participants were created from existing data and compared using t-tests and repeated measures ANOVAs. Qualitative interviews were conducted with participating CR staff then transcribed, coded, and analyzed for key themes. There were significant differences in body mass index and weight from pre-to post-CR within both hybrid and in-person groups. Despite this, CR staff believed exercise adherence was reduced in the hybrid group when compared to those in the in-person program. In the future, TBCR should be considered as an adjunct to in-person CR. Reluctance to prescribe exercise needs to be addressed through CR staff training.

Postoperative delirium prediction using machine learning models and preoperative electronic health record data.

BACKGROUND: Accurate, pragmatic risk stratification for postoperative delirium (POD) is necessary to target preventative resources toward high-risk patients. Machine learning (ML) offers a novel approach to leveraging electronic health record (EHR) data for POD prediction. We sought to develop and internally validate a ML-derived POD risk prediction model using preoperative risk features, and to compare its performance to models developed with traditional logistic regression. METHODS: This was a retrospective analysis of preoperative EHR data from 24,885 adults undergoing a procedure requiring anesthesia care, recovering in the main post-anesthesia care unit, and staying in the hospital at least overnight between December 2016 and December 2019 at either of two hospitals in a tertiary care health system. One hundred fifteen preoperative risk features including demographics, comorbidities, nursing assessments, surgery type, and other preoperative EHR data were used to predict postoperative delirium (POD), defined as any instance of Nursing Delirium Screening Scale ≥2 or positive Confusion Assessment Method for the Intensive Care Unit within the first 7 postoperative days. Two ML models (Neural Network and XGBoost), two traditional logistic regression models ("clinician-guided" and "ML hybrid"), and a previously described delirium risk stratification tool (AWOL-S) were evaluated using the area under the receiver operating characteristic curve (AUC-ROC), sensitivity, specificity, positive likelihood ratio, and positive predictive value. Model calibration was assessed with a calibration curve. Patients with no POD assessments charted or at least 20% of input variables missing were excluded. RESULTS: POD incidence was 5.3%. The AUC-ROC for Neural Net was 0.841 [95% CI 0. 816-0.863] and for XGBoost was 0.851 [95% CI 0.827-0.874], which was significantly better than the clinician-guided (AUC-ROC 0.763 [0.734-0.793], p < 0.001) and ML hybrid (AUC-ROC 0.824 [0.800-0.849], p < 0.001) regression models and AWOL-S (AUC-ROC 0.762 [95% CI 0.713-0.812], p < 0.001). Neural Net, XGBoost, and ML hybrid models demonstrated excellent calibration, while calibration of the clinician-guided and AWOL-S models was moderate; they tended to overestimate delirium risk in those already at highest risk. CONCLUSION: Using pragmatically collected EHR data, two ML models predicted POD in a broad perioperative population with high discrimination. Optimal application of the models would provide automated, real-time delirium risk stratification to improve perioperative management of surgical patients at risk for POD.

Opportunities Beyond the Anesthesiology Department: Broader Impact Through Broader Thinking.

Ensuring a productive clinical and research workforce requires bringing together physicians and communities to improve health, by strategic targeting of initiatives with clear and significant public health relevance. Within anesthesiology, the traditional perspective of the field's health impact has focused on providing safe and effective intraoperative care, managing critical illness, and treating acute and chronic pain. However, there are limitations to such a framework for anesthesiology's public health impact, including the transient nature of acute care episodes such as the intraoperative period and critical illness, and a historical focus on analgesia alone-rather than the complex psychosocial milieu-for pain management. Due to the often episodic nature of anesthesiologists' interactions with patients, it remains challenging for anesthesiologists to achieve their full potential for broad impact and leadership within increasingly integrated health systems. To unlock this potential, anesthesiologists should cultivate new clinical, research, and administrative roles within the health system-transcending traditional missions, seeking interdepartmental collaborations, and taking measures to elevate anesthesiologists as dynamic and trusted leaders. This special article examines 3 core themes for how anesthesiologists can enhance their impact within the health care system and pursue new collaborative health missions with nonanesthesiologist clinicians, researchers, and administrative leaders. These themes include (1) reframing of traditional anesthesiologist missions toward a broader health system-wide context; (2) leveraging departmental and institutional support for professional career development; and (3) strategically prioritizing leadership attributes to enhance system-wide anesthesiologist contributions to improving overall patient health.