Patient motivations for non-adherence to lung cancer screening in a military population.

BACKGROUND: Lung cancer remains the leading cause of cancer deaths in the United States, and lung cancer screening has been shown to decrease this mortality. Adherence to lung cancer screening is paramount to realize the mortality benefit, and reported adherence rates vary widely. Few reports address non-adherence to screening, and our study sought to understand the non-compliant patients in our military population. METHODS: This Institutional Review Board approved retrospective review of patients enrolled in our screening program from 2013-2019 identified patients who failed to obtain a subsequent Low Dose CT scan (LDCT) within 15 months of their prior scan. Attempts were made to contact these patients and elucidate motivations for non-adherence via telephone. RESULTS: Of the 242 patients enrolled, 183 (76%) patients were adherent to the protocol. Significant predictors of non-adherence versus adherence were younger age (P=0.008), female sex (P=0.005), and enlisted officer rank (P=0.03). There was no difference with regards to race, smoking status, pack-years, negative screens, lung-RADS level, or nodule size. 31 (52%) non-adherent patients were contacted, and 24 (77%) reported their reason for non-adherence was lack of follow-up for a LDCT. Twenty (64%) were interested in re-enrollment. Of the total screening cohort, 15 interventions were performed, with lung cancer identified in 5 (2%)-a 67% false positive rate. One stage IV lung cancer was found in a non-adherent patient who re-enrolled. CONCLUSIONS: Lack of perceived contact for follow-up was expressed as the primary reason for non-compliance in our screening program. Compliance is critical to the efficacy of any screening modality, and adherence rates to lung cancer screening may be increased through improved contact with patients via multiple avenues (i.e., phone, email, and letter). There is benefit in contacting non-adherent patients as high rates of re-enrollment are possible.

Correcting a rare Congenital Coronary Anomaly in an Adult-A Case Report.

Anomalous origin of the right coronary artery from the pulmonary artery is an extremely rare condition with an uncertain natural history. Here, we present an otherwise healthy active duty service member who was found to have anomalous right coronary artery arising from the pulmonary artery as an incidental discovery during a workup for possible pulmonary embolus. We describe a preoperative workup which showed dilation of the coronaries and evidence of ischemia. Operative technique for restoration of a two-vessel coronary system is described. Postoperative imaging demonstrated reduction in the coronary dilation and resolution of ischemia.

Intracardiac Heterotopic Liver Presenting as a Right Atrial Myxoma: A Case Report.

Intracardiac heterotopic liver is a very rare entity. The most unique aspect of this entity is the increased carcinogenic potential of the tissue. This condition must be considered when assessing an intracardiac mass along with more common differential diagnoses such as neoplasms, thrombi, and vegetations. In this report, we present a case of a patient who presented to cardiac surgery for elective excision of a right atrial mass that was determined to be an accessory liver lobe. We discuss the diagnostic challenges, clinical management, and surgical and anesthetic implications of this rare finding.

Maintaining Quality in Lower Volume Cardiac Surgery: A Blueprint From a Military Program.

Although there is a clear volume-outcome relationship in the field of cardiac surgery, the existence of high-performing programs with relatively low case volumes is well established. This report describes the programmatic and institutional processes in place at a lower volume cardiac surgery center in a US military hospital, which have been executed to optimally leverage available resources in the delivery of exemplary patient care. By implementing a highly collaborative practice, rigorous outcomes review, evidence-based standardized care pathways, consistent attending surgeon oversight for care delivery, careful case selection, and a mechanism for support from highly experienced outside cardiac surgeons, the cardiac surgery program at the authors' institution delivers care on par with its higher volume counterparts. A review of these practices and available supporting evidence may provide a model for other programs seeking success in this setting.

A novel technique for hybrid aortic arch reconstruction: the deployment cuff technique.

Extensive thoracic aortic aneurysmal disease involving the arch and descending aorta has been a difficult problem. The "frozen elephant trunk" single-stage procedure combining open arch repair under circulatory arrest with a deployment of a stented thoracic endograft has shown good results in recent reports, but it can be technically challenging to deploy the endovascular device in the exact location. In patients with aortic dissection, back bleeding through the false lumen necessitates obliteration of the false lumen proximally. We describe a technique that allows for precise deployment and obliteration of false lumen flow at the proximal end of the stent graft.

Total liquid ventilation provides superior respiratory support to conventional mechanical ventilation in a large animal model of severe respiratory failure.

Total liquid ventilation (TLV) has the potential to provide respiratory support superior to conventional mechanical ventilation (CMV) in the acute respiratory distress syndrome (ARDS). However, laboratory studies are limited to trials in small animals for no longer than 4 hours. The objective of this study was to compare TLV and CMV in a large animal model of ARDS for 24 hours. Ten sheep weighing 53 ± 4 (SD) kg were anesthetized and ventilated with 100% oxygen. Oleic acid was injected into the pulmonary circulation until PaO2:FiO2 ≤ 60 mm Hg, followed by transition to a protective CMV protocol (n = 5) or TLV (n = 5) for 24 hours. Pathophysiology was recorded, and the lungs were harvested for histological analysis. Animals treated with CMV became progressively hypoxic and hypercarbic despite maximum ventilatory support. Sheep treated with TLV maintained normal blood gases with statistically greater PO2 (p < 10(-9)) and lower PCO2 (p < 10(-3)) than the CMV group. Survival at 24 hours in the TLV and CMV groups were 100% and 40%, respectively (p < 0.05). Thus, TLV provided gas exchange superior to CMV in this laboratory model of severe ARDS.

In-parallel artificial lung attachment at high flows in normal and pulmonary hypertension models.

BACKGROUND: End-stage lung disease patients who require a thoracic artificial lung (TAL) must be extubated and rehabilitated prior to lung transplantation. The purpose of this study is to evaluate hemodynamics and TAL function under simulated rest and exercise conditions in normal and pulmonary hypertension sheep models. METHODS: The TAL, the MC3 Biolung (MC3, Inc, Ann Arbor, MI), was attached between the pulmonary artery and left atrium in nine normal sheep and eight sheep with chronic pulmonary hypertension. An adjustable band was placed around the distal pulmonary artery to control the percentage of cardiac output (CO) diverted to the TAL. Pulmonary system hemodynamics and TAL function were assessed at baseline (no flow to the TAL) and with approximately 60%, 75%, and 90% of CO diverted to the TAL. Intravenous dobutamine (0, 2, and 5 mcg . kg(-1). min(-1)) was used to simulate rest and exercise conditions. RESULTS: At 0 and 2 mcg . kg(-1). min(-1), CO did not change significantly with flow diversion to the TAL for both models. At 5 mcg . kg(-1). min(-1), CO decreased with increasing TAL flow up to 28% +/- 5% in normal sheep and 23% +/- 5% in pulmonary hypertension sheep at 90% flow diversion to the artificial lung. In normal sheep, the pulmonary system zeroth harmonic impedance modulus, Z(0), increased with increasing flow diversion. In hypertensive sheep, Z(0) decreased at 60% and 75% flow diversion and returned to baseline levels at 90%. The TAL outlet blood oxygen saturation was 95% or greater under all conditions. CONCLUSIONS: Pulmonary artery to left atrial TAL use will not decrease CO during rest or mild exercise but may not allow more vigorous exercise.

The relationship between pulmonary system impedance and right ventricular function in normal sheep.

Right ventricular (RV) afterload is a key determinant of RV function and is increased in many cardiopulmonary pathologies. Pulmonary circulation input impedance has been used to quantify afterload previously but due to its complexity has not been widely applied. This study examines the effect of a subset of the impedance spectrum, the zeroth and first harmonic impedance moduli (Z (0), Z (1)), on RV performance in large animals. An artificial circuit with adjustable resistance and compliance (C) was implanted into the pulmonary circulation of five sheep. Resistance was varied to increase Z (0) in increments of 2 mmHg/(L/min) until Z (0) was 8 mmHg/(L/min) above baseline. At each Z (0), C was adjusted between 0, 0.5 and 2 mL/mmHg or 0, 1, and 5 mL/mmHg. Fourier transforms of the pulmonary artery pressure and flow in each situation were used to calculate the pulmonary impedance. Results show that the percent change in cardiac output (%DeltaCO) is linearly related to the change in Z (0) (DeltaZ (0)). Increases in Z (1) (DeltaZ (1)) decreased %DeltaCO but to a much smaller degree, with the effect of DeltaZ (1) increasing with DeltaZ (0). Regression of these results produce the equation: %DeltaCO = (-0.0829DeltaZ (1) - 3.65)DeltaZ (0) - 9.02 (R (2) = 0.69). Blood flow and pressure moduli are small at harmonics higher than the first and are unlikely to affect RV function. Therefore, during acute, high afterload states, Z (0) is the primary determinant of CO, while the effect of Z (1) is minor.

Organ donation after cardiac determination of death (DCD): a swine model.

Donors after Cardiac Death (DCD) may reduce the organ scarcity; however, their use is limited because of warm ischemia time. Fortunately, this is less important in a subclass of DCD called expected (e-DCD), those with irreversible but incomplete brain injury. This study analyzed hemodynamic/pulmonary data to establish a clinically relevant model of cardiac death that would simulate an e-DCD setting. Hemodynamics, pulmonary artery flows, arterial blood gasses, and left atrial pressure were recorded q 5 minutes in anesthetized swine. After baseline data collection, the ventilator was discontinued and heparin was administered. Cardiac death was defined: as asystole, or mean arterial presusure < or = 25 mm Hg with a pulse pressure < or = 20 mm Hg. The time to death was approximately 14.8 minutes. Within 5 minutes of removal of the ventilator, there was a hyperdynamic period. Blood gases throughout the apneic time showed a rapid hypercapnia and acidosis. The hyperdynamic reflex response was followed by hypotension, bradycardia, and finally asystole or ventricular fibrillation. The protocol of withdrawal of ventilation, systemic anticoagulation, determination of death was developed to closely resemble the clinical e-DCD scenario. The physiologic changes that happen before death in DCD were described. An e-DCD model that can be used in studies related to organ transplantation was established.

Lung physiology during ECS resuscitation of DCD donors followed by in situ assessment of lung function.

Extracorporeal cardiopulmonary support (ECS) of donors after cardiac death (DCD) has been shown to improve abdominal organs for transplantation. This study assesses whether pulmonary congestion occurs during ECS with the heart arrested and describes an in vivo method to assess if lungs are suitable for transplantation from DCD donors after ECS resuscitation. Cardiac arrest was induced in 30 kg pigs, followed by 10 min of warm ischemia. Cannulae were placed into the right atrium (RA) and iliac artery, and veno-arterial ECS was initiated for 90 min with lungs inflated, group 1 (n = 5) or deflated, group 2 (n = 3). Left atrial pressures were measured as a marker for pulmonary congestion. After 90 min of ECS, lung function was evaluated. Cannulae were placed into the pulmonary artery (PA) and left ventricle (LV). A second pump was included, and ECS was converted to a bi-ventricular (bi-VAD) system. The RVAD drained from the RA and pumped into the PA, and the LVAD drained the LV and pumped into the iliac. This brought the lungs back into circulation for a 1-hr assessment period. The oxygenator was turned off, and ventilation was restarted. Flows, blood gases, PA and left atrial pressures, and compliance were recorded. In both the groups, LA pressure was <15 mm Hg during ECS. During the lung assessment period, PA flows were 1.4-2.2 L/min. PO2 was >300 mm Hg, with normal PCO2. Extracorporeal cardiopulmonary support resuscitation of DCD donors is feasible and allows for assessment of function before procurement. Extracorporeal cardiopulmonary support does not cause pulmonary congestion, and the lungs retain adequate function for transplantation. Compliance correlated with lung function.

Development of an artificial placenta I: pumpless arterio-venous extracorporeal life support in a neonatal sheep model.

PURPOSE: Effective treatment of respiratory failure in premature infants remains an unsolved problem. The development of an artificial placenta, in the form of a pumpless arteriovenous extracorporeal life support (AV-ECLS) circuit that maintains fetal circulation, is an appealing alternative. METHODS: A near-term (140 d/term = 145 days) neonatal lamb model was used (n = 7). Fetuses were exposed by hysterotomy, and flow probes were placed on the ductus arteriosus, aorta, and carotid artery. Catheters were placed into the umbilical vessels, and pumpless AV-ECLS was initiated. Fetuses were submerged in a warm saline bath, and support was maintained for up to 4 hours. RESULTS: Mean initial device flow was 383 mL/min but steadily declined to 177 mL/min at 4 hours. Mean initial pO(2) was 24 mm Hg and 18 mm Hg at 4 hours. Initial mean pCO(2) was 60 mm Hg and declined to 42 mm Hg at 4 hours. Mean arterial pressure was initially 43 mm Hg and decreased to 34 mm Hg at 4 hours. Flow in the ductus arteriosus was maintained for 4 hours. Of 7 fetuses, 5 survived 4 hours of support. CONCLUSIONS: Pumpless AV-ECLS can support gas exchange and maintain fetal circulation in a neonatal lamb model for a 4-hour period. Prolonged support (>4 hours) is hampered by high cannula resistance and declining device flow.