Clinical Immersion of Undergraduate Biomedical Engineering Students: Best Practices for Short-Term Programs.

Many biomedical engineering degree programs lack substantial immersive clinical experiences for undergraduate students, creating a need for clinical immersion programs that contribute to training objectives that emphasize current clinical needs (Becker in Eur J Eng Educ 31:261-272, 2006; Davis et al. in J Eng Educ 91:211-221, 2002; Dym et al. in J Eng Educ 94:103-120, 2005). Immersive clinical experiences have the potential to bridge the gap between clinical and non-clinical learning objectives in biomedical engineering curriculum. In collaboration with Indiana University Health Methodist Hospital, we have created, executed, and evaluated a two-week cardiovascular clinical immersion program for biomedical engineering undergraduate students at Purdue University. As of August 2022, this program has run 11 times since 2014 with 60 participants to date, exposing students to intensive and non-intensive care environments, facilitating interactions with medical professionals, and encouraging exploration of innovative technologies shaping the training of clinicians with direct patient interaction. The variety of cardiovascular topics discussed and clinical settings observed has provided students with a unique, highly beneficial learning opportunity. Keys to the continued success and growth of similar programs include: recruiting a diverse team, support from administrative staff/clinicians, a funded student intern position, and careful consideration of liability/risk management. Areas of future consideration include, streamlining the order of scheduled events, determining if offering course credit would be beneficial to students, and tracking career trajectories after participations.

Trousseau Syndrome in a 25-Year-Old Woman with Occult Colon Malignancy, Lynch Syndrome, and Chronic Thromboembolic Pulmonary Hypertension.

We present a rare case of thrombosis associated with an occult colon malignancy (Trousseau syndrome) in a 25-year-old woman who also presented with previously unidentified Lynch syndrome and acute-on-chronic thromboembolic pulmonary hypertension. Staged treatment included bilateral pulmonary endarterectomy under deep hypothermic circulatory arrest, followed 11 days later by laparoscopic subtotal colectomy and creation of a primary anastomosis. The patient tolerated both procedures well and recovered normal functional status. Final pathologic analysis of the resected colon mass revealed a pT3N0, stage IIA adenocarcinoma; no adjuvant therapy was administered. At her one-year follow-up visit, the patient was cancer-free, remained on lifelong apixaban anticoagulation, and was undergoing routine monitoring and genetic counseling. This case highlights the need for multidisciplinary management of a patient with severe chronic thromboembolic pulmonary hypertension and a concomitant malignancy.

Outcomes of Surgical Coronary Revascularization Performed Before Solid Abdominal Organ Transplants.

BACKGROUND: Cardiac risk stratification and coronary angiography are routinely performed as part of kidney and liver transplant candidacy evaluation. There are limited data on the outcomes of surgical coronary revascularization in this patient population. This study investigated outcomes in patients with end- stage renal or hepatic disease who were undergoing coronary artery bypass grafting (CABG) to attain kidney or liver transplant candidacy. METHODS: This study was a retrospective analysis of all patients who underwent isolated CABG at our institution, Indiana University School of Medicine (Indianapolis, IN), between 2010 and 2016. Patients were divided into 2 cohorts: pretransplant (those undergoing surgery to attain renal or hepatic transplant candidacy) and nontransplant (all others). Baseline characteristics and postoperative outcomes were compared between the groups. RESULTS: A total of 1801 patients were included: 28 in the pretransplant group (n = 22, kidney; n = 7, liver) and 1773 in the nontransplant group. Major adverse postoperative outcomes were significantly greater in the pretransplant group compared with the nontransplant group: 30-day mortality (14.3% vs 2.8%; P = .009), neurologic events (17.9% vs 4.8%; P = .011), reintubation (21.4% vs 5.8%; P = .005), and total postoperative ventilation (5.2 hours vs 5.0 hours; P = .0124). The 1- and 5-year mortality in the pretransplant group was 17.9% and 53.6%, respectively. Of the pretransplant cohort, 3 patients (10.7%) underwent organ transplantation (all kidney) at a mean 436 days after CABG. No patients underwent liver transplantation. CONCLUSIONS: Outcomes after CABG in pre-kidney transplant and pre-liver transplant patients are poor. Despite surgical revascularization, most patients do not ultimately undergo organ transplantation. Revascularization strategies and optimal management in this high-risk population warrant further study.

Impact of troponin I level on coronary artery bypass grafting outcomes.

PURPOSE: The effect of preoperative cardiac troponin level on outcomes after coronary artery bypass grafting (CABG) is unclear. We investigated the impact of preoperative cardiac troponin I (cTnI) level as well as the time interval between maximum cTnI and surgery on CABG outcomes. METHODS: All patients who underwent isolated CABG at our institution between 2009 and 2016 and had preoperative cTnI level available were identified using our Society of Thoracic Surgeons registry. Receiver operating characteristic (ROC) analysis was performed to identify a cTnI threshold level. Subjects were divided into groups based on this value and outcomes compared. RESULTS: A total of 608 patients were included. ROC analysis identified 5.74 µg/dL as the threshold value associated with worse postoperative outcomes. Patients with peak cTnI >5.74 µg/dL underwent CABG approximately 1 day later, had twice the risk of adverse postoperative events, and had 2.8 day longer postoperative length of stay than those with peak cTnI ≤5.74 µg/dL. cTnI level was not associated with mortality or 30-day readmission. Time interval between peak cTnI and surgery did not affect outcomes. CONCLUSION: Elevated preoperative cTnI level beyond a certain threshold value is associated with adverse postoperative outcomes but is not a marker for increased mortality. Time from peak cTnI does not affect postoperative outcomes or mortality and may not need to be considered when deciding timing of CABG.

The presence of a dedicated cardiac surgical intensive care service impacts clinical outcomes in adult cardiac surgery patients.

BACKGROUND: Postoperative critical care management is an integral part of cardiac surgery that contributes directly to clinical outcomes. In the United States there remains considerable variability in the critical care infrastructure for cardiac surgical programs. There is little published data investigating the impact of a dedicated cardiac surgical intensive care service. METHODS: A retrospective study examining postoperative outcomes in cardiac surgical patients before and after the implementation of a dedicated cardiac surgical intensive care service at a single academic institution. An institutional Society of Thoracic Surgeons database was queried for study variables. Primary endpoints were the postoperative length of stay, intensive care unit length of stay, and mechanical ventilation time. Secondary endpoints included mortality, readmission rates, and postoperative complications. The effect on outcomes based on procedure type was also analyzed. RESULTS: A total of 1703 patients were included in this study-914 in the control group (before dedicated intensive care service) and 789 in the study group (after dedicated intensive care service). Baseline demographics were similar between groups. Length of stay, mechanical ventilation hours, and renal failure rate were significantly reduced in the study group. Coronary artery bypass grafting patients observed the greatest improvement in outcomes. CONCLUSIONS: Implementation of a dedicated cardiac surgical intensive care service leads to significant improvements in clinical outcomes. The greatest benefit is seen in patients undergoing coronary artery bypass, the most common cardiac surgical operation in the United States. Thus, developing a cardiac surgical intensive care service may be a worthwhile initiative for any cardiac surgical program.

Severe re-expansion pulmonary edema after conventional cardiac surgery: Identification and management.

Re-expansion Pulmonary Edema (REPE) is a recognized but rare complication of lung re-inflation after pathologic collapse or intentional deflation. The presentation of REPE may be highly variable, ranging from a clinically asymptomatic, incidental radiologic finding to acute respiratory failure accompanied by severe, life-threatening hypoxemia. With the current report, we present a patient with severe aortic insufficiency, severe mitral regurgitation, coronary artery disease, pulmonary hypertension, who underwent aortic valve replacement, mitral valvuloplasty, coronary artery bypass grafting, and developed at the immediate post- operative period severe respiratory failure due to REPE, requiring venous-venous Extracorporeal Membrane Oxygenation (VV-ECMO).

Long-term results with cryopreserved arterial allografts (CPAs) in the treatment of graft or primary arterial infections.

OBJECTIVE: Our purpose was to evaluate our results with CPAs in patients with infected grafts or primary arterial infection with emphasis on long-term durability of these grafts. METHODS: To evaluate the long-term durability of CPAs, clinical outcomes were analyzed following their use for either graft or primary arterial infections at a single institution over a 9-y period (2000-2009). The 30-d mortality rate, 90-d mortality rate, and the cause of early mortality were determined in each case. Among those surviving 90 d, the grafts were evaluated for subsequent failure. RESULTS: From 2000 through 2009, 51 patients with either infected prosthetic grafts (35) or primary arterial infections (15) received CPAs. One patient had infection of a previously placed thoracic allograft. Forty-three graft infections involved either the thoracic or abdominal aorta. Eleven patients presented with fulminant sepsis with systemic inflammatory response syndrome (SIRS), seven of whom died postoperatively. Eight patients presented with aorto-enteric, esophageal, or bronchial fistulae with infected prosthetic grafts. The 30-d mortality rate was 25.5% (11 deaths) seven of which occurred in patients with SIRS. The 90-d mortality rate was 41.4%. There were 10 graft failures, seven occurring in patients with aorto-enteric or bronchial fistulae all of whom had recurrent hemorrhage. The other three graft failures were due to anastomotic hemorrhage in the early postoperative period. Among those surviving 90 d, the mean follow-up was 46.4 mo (range 1-112 mo). No aneurysmal degeneration of the CPAs was noted. Only one subsequent allograft graft failure was noted among those surviving more than 90 d. CONCLUSIONS: CPAs are a suitable option in dealing with cardiovascular infections. Patients with enteric or bronchial fistulae are a difficult group to treat perhaps because of ongoing contamination of the allograft. The operative mortalities are largely determined by patient comorbidities (SIRS). Subsequent degeneration or infection of the CPAs is rare.

Surgical treatment of atrial fibrillation: the time is now.

Atrial fibrillation (AF) is the most common chronic arrhythmia in the United States and is associated with high morbidity rates and significant healthcare costs. Although medical therapy for AF modestly reduces complications, cardiac surgery continues to have an important role in the treatment of AF and is constantly evolving. Cardiothoracic surgeons are uniquely positioned to offer effective operations to patients with lone AF, in addition to those undergoing concomitant elective cardiac surgery. This review discusses (1) the burden of AF, (2) classification and electrophysiology of AF, (3) surgical techniques and outcomes, and (4) future directions in surgical therapy.

Proinflammatory cytokine effects on mesenchymal stem cell therapy for the ischemic heart.

Mesenchymal stem cells (MSCs) hold great promise for improving myocardial recovery after ischemia. The cardiothoracic surgeon is uniquely positioned to be at the forefront of any clinical application of this therapy. As such, a basic understanding of stem cells and the cytokines that affect stem cell function will be an essential component of the surgeon's ever-expanding knowledge base. This review provides: (1) a general overview of stem cells and MSCs in particular, (2) critically analyzes several cytokines known to alter MSC function, and (3) discusses methods to manipulate cytokine-activated MSCs to improve MSC function for potential clinical application.

The effect of pastoral care services on anxiety, depression, hope, religious coping, and religious problem solving styles: a randomized controlled study.

This randomized controlled study measured the effect of chaplain interventions on coronary artery bypass graft (CABG) patients over time. One hundred sixty-six CABG patients, received pre- and post-surgery testing at 1 month and 6 months with four instruments. Five chaplain visits were made to the intervention group, the control group received none. Comparison scores for anxiety, depression, hope, positive and negative religious coping, and religious coping styles were analyzed. Significant difference was found between groups in positive religious coping (PRC) (p = .023) and negative religious coping (NRC) (p = .046) scores over time. PRC increased in intervention group, decreased in the control group while NRC decreased in intervention group and increased in the control group. Demographics were comparable between groups. Moderate chaplain visits (average total visits time, 44 min) may be effective in helping CABG patients increase positive religious coping and decrease negative religious coping.

Pain levels experienced with activities after cardiac surgery.

BACKGROUND: Acute pain is common after cardiac surgery and can keep patients from participating in activities that prevent postoperative complications. Accurate assessment and understanding of pain are vital for providing satisfactory pain control and optimizing recovery. OBJECTIVES: To describe pain levels for 5 activities expected of patients after cardiac surgery on postoperative days 1 to 6 and changes in pain levels after chest tube removal and extubation. METHODS: Adults who underwent cardiac surgery were asked to rate the pain associated with various types of activities on postoperative days 1 to 6. Pain levels were compared by postoperative day, activity, and type of cardiac surgery. Pain scores before and after chest tube removal and extubation also were analyzed. RESULTS: Pain scores were higher on earlier postoperative days. The order of overall pain scores among activities (P < .01) from highest to lowest was coughing, moving or turning in bed, getting up, deep breathing or using the incentive spirometer, and resting. Changes in pain reported with coughing (P = .03) and deep breathing or using the incentive spirometer (P = .005) differed significantly over time between surgery groups. After chest tubes were discontinued, patients had lower pain levels at rest (P = .01), with coughing (P = .05), and when getting up (P = .03). CONCLUSIONS: Pain relief is an important outcome of care. A comprehensive, individualized assessment of pain that incorporates activity levels is necessary to promote satisfactory management of pain.

Evaluation of hemodynamics: comparison of vacuum and mechanical stabilization in the beating heart.

BACKGROUND: Hemodynamic instability remains a prominent concern for surgeons performing coronary surgery without cardiopulmonary bypass. The purpose of this study was to further elucidate the mechanism of hemodynamic instability by comparing vacuum stabilization to mechanical stabilization. METHODS: Four 60-kg swine were placed under general anesthesia. A median sternotomy incision was made, and baseline hemodynamic measurements were recorded. Mechanical and vacuum stabilization of the circumflex distribution were alternately compared with repeated baseline measurements in a counterbalanced method, and 32 experiments were conducted. RESULTS: There were significant differences between baseline hemodynamics and stabilized hemodynamics for mechanical stabilization versus vacuum stabilization, respectively, for the following parameters: blood pressure (mean decrement), -32.18% (P =.0028) versus -31.3% (P =.0006); cardiac output, -31.03% (P =.0046) versus -35.2% (P =.03); and mixed venous oxygen saturation, -29.8% (P =.008) versus -27.4% (P =.0004). There were no statistical differences between mechanical and vacuum stabilization when their decremental effects on baseline hemodynamics were compared with each other for any of the measured variables. CONCLUSIONS: The mechanisms of hemodynamic compromise during coronary stabilization remain to be fully elucidated. Our study demonstrates no statistical difference between vacuum and mechanical stabilization on the measured hemodynamic values. More sophisticated studies involving detailed analysis of motion and geometry are required so that technical solutions to hemodynamic instability can be developed.