Liposomal Bupivacaine Versus Bupivacaine for Intercostal Nerve Blocks in Thoracic Surgery: A Retrospective Analysis.

BACKGROUND: Liposomal bupivacaine (LipoB), delivered via intercostal nerve blocks (ICNBs), is increasingly being used for postoperative pain control in thoracic surgery patients, but there is limited data on its effectiveness when compared to standard bupivacaine. OBJECTIVE: We sought to compare postoperative opioid use, pain control, and length of stay (LOS) in patients undergoing thoracic surgery with LipoB ICNBs vs patients undergoing thoracic surgery with ICNBs using standard bupivacaine. STUDY DESIGN: A retrospective analysis. SETTING: Research took place in a tertiary academic medical center. METHODS: A transition in the standard of care from standard bupivacaine to LipoB for ICNBs in March of 2014 allowed us to compare 2 cohorts: patients who received bupivacaine ICNBs from January 2013 through February of 2014 and patients who received LipoB ICNBs from March 2015 through November 2017. We included patients who underwent thoracic surgery for lung cancer using robotic-assisted thoracic surgery (RATS), video-assisted thoracic surgery (VATS), or traditional open thoracotomy, and documentation of ICNB in the operative note. We collected data on pain scores (Visual Analog Scale [VAS]) and opioid consumption (converted to oral morphine equivalents [OMEs]) intraoperatively, on postoperative day (POD) 0, POD 1, POD 2, and POD 3. We also analyzed data on length of stay [LOS]. A primary analysis was performed on the effects of LipoB vs bupivacaine across all surgery types on opioid consumption, pain scores, and LOS with a secondary analysis on the same endpoints per individual surgery type. RESULTS: A total of 129 patients were included from the predefined study periods (n = 62 LipoB and n = 67 standard bupivacaine). Across all surgery types, LipoB decreased opioid utilization vs standard bupivacaine (P < .01). Post-hoc testing revealed that this difference existed intraoperatively (55 ± 5 vs 69 ± 4 mg OME, P = .03) and on POD 0 (44 ± 6 vs 68 ± 6 mg OME, P < .01). Surgical subtype analysis revealed that this difference was mostly driven by lower opioid consumption in patients undergoing RATS. When compared across all surgery types, LipoB vs bupivacaine did not affect postoperative pain scores. However, subgroup analysis showed that pain scores were lower in the LipoB vs standard bupivacaine group undergoing VATS on POD 0, 1, and 2. The LOS across all thoracic surgery types was lower in the LipoB group when compared to the standard bupivacaine group (median, 4 days [IQR 2.0-6.0] vs median, 5 days [IQR 3.0-8.0], P < .01). Subgroup analysis showed that the LOS in patients undergoing VATS with LipoB ICNBs was shorter compared to patients receiving bupivacaine ICNBs. LIMITATIONS: The retrospective nature of this study makes it prone to several types of bias. CONCLUSION: ICNBs with LipoB for thoracic surgery leads to lower opioid consumption and shorter LOS when compared to ICNBs with standard bupivacaine. The benefit of LipoB over standard bupivacaine for ICNBs appears especially relevant in VATS or RATS procedures. KEY WORDS: Intercostal nerve block, liposomal bupivacaine, RATS, regional anesthesia, robotic-assisted thoracoscopic surgery, thoracotomy, VATS, video-assisted thoracoscopic surgery.

Nontraumatic ascending aortic disruption.

This report documents a case of completely spontaneous ascending aortic disruption. A 54-year-old African American male day laborer presented with severe retro-sternal chest and back pain and shortness of breath. He had no history of hypertension, smoking, or trauma and was taking no medications. The computed tomographic angiography scan performed to exclude pulmonary embolism instead demonstrated a hemorrhagic pericardial effusion and an ascending aortic pseudoaneurysm. He was taken emergently to the operating room for repair of his ascending aorta. The histopathology report was normal.

Traumatic innominate artery pseudoaneurysm in the setting of a bovine arch.

Blunt traumatic injury of the innominate artery occurs infrequently but is commonly lethal. Bovine aortic arch anatomy is a predisposition to this injury. Clinical findings, chest X-ray, and computerized tomography may suggest the diagnosis, and it may be confirmed with angiography. Both interposition and bypass grafting are operative repair methods of choice. EEG monitoring confirms cerebral perfusion, thereby allowing the deferment of shunts and cardiovascular bypass with hypothermic arrest. We report a case of traumatic innominate artery pseudoaneurysm in the setting of "bovine aortic arch" anatomy, together with multiple associated injuries, including descending aorta transection. We also review the current literature on the topic.

Antegrade thoracic stent grafting during repair of acute DeBakey I dissection prevents development of thoracoabdominal aortic aneurysms.

BACKGROUND: Acute DeBakey I dissection repair consists of ascending aortic resection, aortic root repair or replacement, and variable aortic arch replacement. This "proximal" strategy leaves most patients with a patent residual "type B" dissection which leads to greater than 30% distal "open" reoperations for dissecting aneurysm. This report tests whether antegrade stent-grafting of the proximal descending thoracic aorta during acute DeBakey I dissection decreases future distal aortic aneurysms without an increase in surgical risk. METHODS: Between June 2005 and June 2008, 150 patients were treated surgically for acute type A aortic dissection at the Hospital of the University of Pennsylvania. Of these, 78 were DeBakey I dissections: 42 patients underwent standard open repair, while 36 underwent additional thoracic stent-grafting by the open arch. Arch repairs were performed with a combination of retrograde cerebral and selective antegrade perfusion. RESULTS: Mean follow-up was 15.9 months. Hospital mortality was 5 of 36 (14%) for stented and 6 of 42 (14%) for nonstented repairs. Postoperative strokes were 1 of 36 (3%) in stented versus 4 of 42 (10%) in nonstented repairs (p = not significant [NS]) despite longer circulatory arrest times in the stented group; 60 +/- 13 minutes versus 41 +/- 18 minutes (p < 0.0001). Transient paraparesis was 3 of 36 (9%) in the stented versus 1 of 42 (2%) in the nonstented group (p = NS) with no permanent deficits. Stented thoracic false lumen obliteration was achieved in 24 of 30 (80%) with 5 of these (17%) achieving complete thoracoabdominal false lumen thrombosis. Eight of 31 (26%) stented patients underwent endovascular reintervention to achieve the desired false lumen obliteration. Open thoracoabdominal aortic aneurysm repairs were performed in 0 of 31 in the stented group and 4 of 36 (11%) in the standard group (p = 0.083). CONCLUSIONS: Antegrade stent graft deployment during acute DeBakey I dissection repair is a safe method to obliterate the thoracic false lumen. Endovascular reinterventions were well-tolerated. "Elephant trunk" thoracic stent-grafting as part of the repair for acute DeBakey I dissection gives equal short-term results compared with standard repair, and lowers morbidity and mortality during follow-up.

Reoperative aortic root replacement in patients with previous aortic surgery.

BACKGROUND: Reoperative aortic root reconstruction is increasingly performed and remains a clinical challenge. The aim of this study is to evaluate the outcome of patients undergoing reoperative aortic root replacement after previous aortic surgery. METHODS: From 1995 to 2006, 156 consecutive patients underwent reoperative aortic root replacement after previous aortic valve replacement (group 1, n = 106, 67.8%), proximal aortic reconstruction (group 2, n = 25, 16.1%), and aortic root replacement (group 3, n = 25, 16.1%). Their records were retrospectively reviewed. RESULTS: The mean age was 58.1 +/- 14.4 years, and 73.7% (n = 115) were men. Reoperation was performed 98.4 months after previous operation, with 14.7% (n = 23) having undergone three or more sternotomies. Indications for reoperations were endocarditis in 55 (35.3%), prosthetic valve dysfunction in 28 (17.9%), paravalvular leak in 12 (7.7%), aortic aneurysm or pseudoaneurysm in 29 (18.5%), aortic dissection in 12 (7.7%), and aortic stenosis or insufficiency in 20 (12.9%). Aortic root replacement was performed in all 156 patients, with concomitant hemiarch reconstruction in 62 (39.7%), Cabrol coronary reconstruction in 5 (3.2%), coronary artery bypass grafting (CABG) in 26 (16.6%), and mitral valve repair or replacement (MVR) in 25 (16.0%). Thirty-day mortality was 11.5% (n = 18). Actuarial survival was 86.4% +/- 2.7% at 1 year, 72.6% +/- 4.3% at 5 years, and 58.4% +/- 7.8% at 10 years. Subgroup analysis demonstrated no difference in 30-day mortality (group 1, 14.1%; group 2, 8.0%; group 3, 4.0%; p = 0.31) and late survival between the three groups (p = 0.14). Multivariate analysis demonstrated age older than 75 years (p = 0.03) and New York Heart Association (NYHA) functional class IV (p = 0.05) as risk factors for 30-day mortality. CONCLUSIONS: Reoperative aortic root reconstruction can be performed with a low perioperative mortality rate and satisfactory long-term survival. Age older than 75 years and NYHA class IV are risk factors for early mortality. Previous aortic root replacement is not a risk factor for reoperative aortic root reconstruction.

The hybrid total arch repair: brachiocephalic bypass and concomitant endovascular aortic arch stent graft placement.

BACKGROUND: Repair of aortic arch aneurysm is technically demanding, requiring complex circulatory management. Very large atherosclerotic saccular aneurysms of the arch are grave markers of extensive arch and brachiocephalic atheromatous disease and represent high surgical risks for perioperative neurologic complications. Operative morbidity and mortality may be prohibitive with traditional surgical intervention. We described our experience with a hybrid procedure for total arch repair with a brachiocephalic bypass with a trifurcated graft followed by concomitant placement of a stent graft in the arch. METHODS: Since June 2005, we have performed the hybrid total arch repair in eight patients. A retrospective review was performed to evaluate the new technique. RESULTS: The mean age of the patients was 67 years with a mean aneurysm size of 8 cm (range, 4.4 to 10 cm). Significant comorbidities included carotid stenosis, chronic renal insufficiency, peripheral vascular disease, hypertension, and coronary artery disease. Two patients had previous Abdominal aortic aneurysm (AAA) repairs. Three patients had previous sternotomy for type A dissection, ascending aortic aneurysm repair, and coronary artery bypass grafting. Transesophageal echocardiogram demonstrated grade IV or V atheromatous disease in the arch and ascending aorta. Stent grafts were deployed antegrade directly into the ascending aorta in three patients and retrograde from the femoral artery in five patients. Technical success with complete aneurysmal exclusion was achieved in all patients (100%). At a mean follow-up period of 11.7 months, there was no incidence of endoleak. There was one death resulting from a perioperative myocardial infarction (first patient). Documented perioperative neurologic events (stroke) occurred in two patients, with both patients demonstrating no residual deficit at the time of discharge. CONCLUSIONS: Saccular arch aneurysms can be technically treated by total arch repair with brachiocephalic bypass and concomitant aortic arch stent graft placement. Hybrid arch repair provides an alternative to patients otherwise considered prohibitively high risk for traditional open arch repair.

Management of type A aortic dissection and a large pheochromocytoma: a surgical dilemma.

The concomitant presence of an undiagnosed pheochromocytoma at the time of an acute type A aortic dissection creates a difficult management dilemma. The case of a patient with an acute type A aortic dissection and pheochromocytoma was stabilized with catecholamine blockade before undergoing ascending aortic and total arch replacement. Fourteen days later the patient underwent resection of the pheochromocytoma. Temporizing medical stabilization of the pheochromocytoma with catecholamine blockade for a period of 5 days allowed for safe aortic reconstruction and seems to be prudent, provided that the aortic dissection remains relatively stable.

Postnatal changes in pulmonary mechanics and energetics of infants with respiratory distress syndrome following surfactant treatment.

BACKGROUND: Postnatal alterations in pulmonary mechanics, energetics and functional residual capacity (FRC) describe the structural maturation of the preterm respiratory system. OBJECTIVE: To evaluate longitudinal changes in pulmonary function in infants with respiratory distress syndrome (RDS) treated with oxygen, positive pressure ventilation and synthetic surfactant (Exosurf). METHODS: Serial pulmonary function tests were performed in surfactant-treated infants [mean +/- SD birth weight (BW) = 1,112 +/- 276 g, gestational age (GA) = 29 +/- 3 weeks] at postnatal ages: <3 days, 1, 2, 3, 4 and 6-8 weeks until term postmenstrual age (PMA). Tidal volume, pulmonary compliance (C(L)), pulmonary resistance (R(T)) and flow-resistive work were analyzed following simultaneous measurements of airflow and transpulmonary pressure signals. Serial FRC measurements were made in a randomly selected group. RESULTS: Prior to 28 weeks' PMA, C(L) was unchanged irrespective of GA. At age 1 week the likelihood ratio (LR) for bronchopulmonary dysplasia (BPD) based on C(L), R(T) and GA was predicted to be >90% for those with BW <750 g (LR >100) as compared to <10% probability (LR = 0.3) for infants >1,500 g. Significant linear increase in C(L) to PMA was evident >28 weeks' PMA (r = 0.86, p < 0.01) at 0.17 ml/cm H2O/kg/week. By term PMA, mean C(L) was 2.60 +/- 0.07 ml/cm H2O. Improvements in FRC of preterm infants with RDS who recovered occur at a more rapid rate ( approximately 25 ml/kg) compared to those who developed BPD ( approximately 20 ml/kg). CONCLUSIONS: Slow but incremental postnatal pulmonary improvement, minimal <28 weeks' PMA, were comparable for all infants. Along with diminished FRC, these changes reflect persistent deleterious effects of positive pressure ventilation, alveolar hyperoxia and unrecognized pulmonary overdistension.

An ovine model of postinfarction dilated cardiomyopathy.

BACKGROUND: Coronary arterial disease is the major cause of congestive heart failure, but suitable animal models of postinfarction, dilated cardiomyopathy do not exist. This article describes an ovine model that develops after an anterobasal infarction. METHODS: The distribution of ovine myocardium supplied by the first two diagonal branches of the left homonymous artery were determined in 20 slaughterhouse hearts and eight live sheep using methylene blue and tetrazolium injections, respectively. Seven additional animals had the infarction and underwent serial hemodynamic, microsphere and echocardiographic studies more than 8 weeks and histologic studies at the eighth week. Infarcts represented 24.6% +/- 4.7% and 23.9% +/- 2.2% of the left ventricular mass in slaughterhouse and live hearts, respectively. RESULTS: During remodeling, left ventricular end-systolic and end-diastolic volumes increased 115% and 73%, respectively, ejection fraction decreased from 41.2% +/- 6.7% to 29.1% +/- 5.7%, systolic wall thickening remote from the infarct decreased by 68%, sphericity index increased from 0.465 +/- 0.088 to 0.524 +/- 0.038, and left ventricular end-diastolic pressure increased from 1.7 +/- 1.0 to 8.2 +/- 3.5 mm Hg. Serial microsphere measurements documented normal blood flow (1.34 mL/g per minute) to all uninfarcted myocardium and 22% of normal to the infarct. Viable myocardium showed mild interstitial fibrosis. CONCLUSIONS: This ovine model meets all criteria for postinfarction, dilated cardiomyopathy and has the advantages of controlling for variations in coronary arterial anatomy, collateral vascularity, and differences in the numbers, location, and severity of atherosclerotic lesions that confound human studies of the pathogenesis of this disease. This simple model contains only infarcted and fully perfused, hypocontractile myocardium produced by a moderate-sized, regional infarction.

Effect of annular shape on leaflet curvature in reducing mitral leaflet stress.

BACKGROUND: Leaflet curvature is known to reduce mechanical stress. There are 2 major components that contribute to this curvature. Leaflet billowing introduces the most obvious form of leaflet curvature. The saddle shape of the mitral annulus imparts a more subtle form of leaflet curvature. This study explores the relative contributions of leaflet billowing and annular shape on leaflet curvature and stress distribution. METHODS AND RESULTS: Both numerical simulation and experimental data were used. The simulation consisted of an array of numerically generated mitral annular phantoms encompassing flat to markedly saddle-shaped annular heights. Highest peak leaflet stresses occurred for the flat annulus. As saddle height increased, peak stresses decreased. The minimum peak leaflet stress occurred at an annular height to commissural width ratio of 15% to 25%. The second phase involved data acquisition for the annulus from 3 humans by 3D echocardiography, 3 sheep by sonomicrometry array localization, 2 sheep by 3D echocardiography, and 2 baboons by 3D echocardiography. All 3 species imaged had annuli of a similar shape, with an annular height to commissural width ratio of 10% to 15%. CONCLUSION: The saddle shape of the mitral annulus confers a mechanical advantage to the leaflets by adding curvature. This may be valuable when leaflet curvature becomes reduced due to diminished leaflet billowing caused by annular dilatation. The fact that the saddle shape is conserved across mammalian species provides indirect evidence of the advantages it confers. This analysis of mitral annular contour may prove applicable in developing the next generation of mitral annular prostheses.