Implications of Pleural Fluid Composition in Persistent Pleural Effusion following Orthotopic Liver Transplant.

Persistent pleural effusions (PPEf) represent a known complication of orthotopic liver transplant (OLT). However, their clinical relevance is not well described. We evaluated the clinical, biochemical, and cellular characteristics of post-OLT PPEf and assessed their relationship with longitudinal outcomes. We performed a retrospective cohort study of OLT recipients between 2006 and 2015. Included patients had post-OLT PPEf, defined by effusion persisting >30 days after OLT and available pleural fluid analysis. PPEf were classified as transudates or exudates (ExudLight) by Light's criteria. Exudates were subclassified as those with elevated lactate dehydrogenase (ExudLDH) or elevated protein (ExudProt). Cellular composition was classified as neutrophil- or lymphocyte-predominant. Of 1602 OLT patients, 124 (7.7%) had PPEf, of which 90.2% were ExudLight. Compared to all OLT recipients, PPEf patients had lower two-year survival (HR 1.63; p = 0.002). Among PPEf patients, one-year mortality was associated with pleural fluid RBC count (p = 0.03). While ExudLight and ExudProt showed no association with outcomes, ExudLDH were associated with increased ventilator dependence (p = 0.03) and postoperative length of stay (p = 0.03). Neutrophil-predominant effusions were associated with increased postoperative ventilator dependence (p = 0.03), vasopressor dependence (p = 0.02), and surgical pleural intervention (p = 0.02). In summary, post-OLT PPEf were associated with increased mortality. Ninety percent of these effusions were exudates by Light's criteria. Defining exudates using LDH only and incorporating cellular analysis, including neutrophils and RBCs, was useful in predicting morbidity.

Postoperative Trapped Lung After Orthotopic Liver Transplantation is a Predictor of Increased Mortality.

Pleural effusions are a common complication of orthotopic liver transplantation (OLT), and chronic post-OLT pleural effusions have been associated with worse outcomes. Furthermore, "trapped lung" (TL), defined as a restrictive fibrous visceral pleural peel preventing lung re-expansion, may have prognostic significance. We performed a retrospective analysis of adult OLT recipients over a 9-year period at UCLA Medical Center. Post-OLT patients with persistent pleural effusions, defined by the presence of pleural fluid requiring drainage one to 12 months after OLT, were included for analysis. Outcomes for patients with and without TL were compared using univariate and multivariate analysis. Of the 1722 patients who underwent OLT, 117 (7%) patients met our criteria for persistent postoperative pleural effusion, and the incidence of TL was 21.4% (25/117). Compared to patients without TL, those with TL required more surgical pleural procedures (OR 59.8, 95%CI 19.7-181.4, p < 0.001), spent more days in the hospital (IRR 1.56, 95%CI 1.09-2.23, p = 0.015), and had a higher risk of mortality (HR 2.47, 95%CI 1.59-3.82, p < 0.001) following transplant. In sum, we found that post-OLT TL was associated with higher morbidity, mortality, and healthcare utilization. Future prospective investigation is warranted to further clarify the risk factors for developing postoperative pleural effusions and TL.

Preoperative Trapped Lung Is Associated With Increased Mortality After Orthotopic Liver Transplantation.

INTRODUCTION: Trapped lung, characterized by atelectatic lung unable to reexpand and fill the thoracic cavity due to a restricting fibrous visceral pleural peel, is occasionally seen in patients with end-stage liver disease complicated by hepatic hydrothorax. Limited data suggest that trapped lung prior to orthotopic liver transplantation may be associated with poor outcomes. RESEARCH QUESTION: What is the clinical significance of trapped lung in patients receiving orthotopic liver transplantation? DESIGN: We performed a retrospective analysis of patients who underwent liver transplantation over an 8-year period. Baseline clinical characteristics and postoperative outcomes of adult patients with trapped lung were analyzed and compared to the overall cohort of liver transplant recipients and controls matched 3:1 based on age, sex, Model for End-Stage Liver Disease (MELD) score, and presence of pleural effusion. RESULTS: Of the 1193 patients who underwent liver transplantation, we identified 20 patients (1.68%) with trapped lung. The probability of 1 and 2-year survival were 75.0% and 57.1%, compared to 85.6% and 80.4% (p = 0.02) in all liver transplant recipients and 87.9% and 81.1% (p = 0.03) in matched controls respectively. Patients with trapped lung had a longer hospital length of stay compared to the total liver transplant population (geometric mean 54.9 ± 8.4 vs. 27.2 ± 0.7 days, p ≤ 0.001), when adjusted for age and MELD score. DISCUSSION: Patients with trapped prior to orthotopic liver transplantation have increased probability of mortality as well as increased health care utilization. This is a small retrospective analysis, and further prospective investigation is warranted.

Development of secondary bacterial pneumonia in adults presenting with influenza versus noninfluenza viral respiratory infection.

BACKGROUND: Respiratory viral infections, particularly influenza, are known to cause significant morbidity and mortality, often due to secondary infections. Our aim was to comparatively analyze the incidence, epidemiology, and outcomes of secondary pneumonia in adult patients hospitalized with influenza versus noninfluenza viral infections and determine whether influenza particularly predisposes to secondary infections. METHODS: This was a retrospective analysis from a single tertiary medical center of adult patients admitted to the hospital between 2008 and 2010 with respiratory viral infections. Microbiological patterns and clinical outcomes were compared between those with influenza (VI, n = 57) and those with noninfluenza (NI, n = 77) respiratory viral infections. RESULTS: The NI group was older (60.6 ± 14.0 versus 53.3 ± 19.7 years, p = 0.019) with higher rates of lung transplantation (29% versus 9%, p = 0.009) than VI. Overall, 35% developed secondary pneumonia, higher among NI (44%) than VI (23%, p = 0.017). Staphylococcus aureus was the most common cause of pneumonia in VI, whereas Gram-negative rods were most frequently identified in NI. The NI group had longer hospital [median 10 (interquartile range (IQR) 6-19) versus 6 (IQR 4-15) days, p = 0.019] and intensive care unit [median 4 (IQR 0-12) versus 0 (IQR 0-8) days, p = 0.029] stays compared with VI. Further, the NI group was more likely to be admitted to the intensive care unit compared with VI (62% versus 39%, p = 0.011). A trend towards increased mortality was observed in viral infections complicated by secondary pneumonia than primary viral infections (28% versus 15%, p = 0.122). CONCLUSION: Secondary pneumonia is common among adults hospitalized with viral respiratory infections. Within our population, NI results in more frequent secondary pneumonia and longer hospital stays than those with VI. Given the high number of infections caused by Gram-negative rods, monitoring local epidemiology is critical for guiding initial antibiotic selection in empirical treatment of secondary infections.The reviews of this paper are available via the supplemental material section.

Unexplained exertional intolerance associated with impaired systemic oxygen extraction.

PURPOSE: The clinical investigation of exertional intolerance generally focuses on cardiopulmonary diseases, while peripheral factors are often overlooked. We hypothesize that a subset of patients exists whose predominant exercise limitation is due to abnormal systemic oxygen extraction (SOE). METHODS: We reviewed invasive cardiopulmonary exercise test (iCPET) results of 313 consecutive patients presenting with unexplained exertional intolerance. An exercise limit due to poor SOE was defined as peak exercise (Ca-vO2)/[Hb] ≤ 0.8 and VO2max < 80% predicted in the absence of a cardiac or pulmonary mechanical limit. Those with peak (Ca-vO2)/[Hb] > 0.8, VO2max ≥ 80%, and no cardiac or pulmonary limit were considered otherwise normal. The otherwise normal group was divided into hyperventilators (HV) and normals (NL). Hyperventilation was defined as peak PaCO2 < [1.5 × HCO3 + 6]. RESULTS: Prevalence of impaired SOE as the sole cause of exertional intolerance was 12.5% (32/257). At peak exercise, poor SOE and HV had less acidemic arterial blood compared to NL (pHa = 7.39 ± 0.05 vs. 7.38 ± 0.05 vs. 7.32 ± 0.02, p < 0.001), which was explained by relative hypocapnia (PaCO2 = 29.9 ± 5.4 mmHg vs. 31.6 ± 5.4 vs. 37.5 ± 3.4, p < 0.001). For a subset of poor SOE, this relative alkalemia, also seen in mixed venous blood, was associated with a normal PvO2 nadir (28 ± 2 mmHg vs. 26 ± 4, p = 0.627) but increased SvO2 at peak exercise (44.1 ± 5.2% vs. 31.4 ± 7.0, p < 0.001). CONCLUSIONS: We identified a cohort of patients whose exercise limitation is due only to systemic oxygen extraction, due to either an intrinsic abnormality of skeletal muscle mitochondrion, limb muscle microcirculatory dysregulation, or hyperventilation and left shift the oxyhemoglobin dissociation curve.

Predictors of Outcomes After Thoracic Surgery in Orthotopic Liver Transplant Recipients With Pleural Disease.

Orthotopic liver transplant (OLT) recipients are at high risk for postoperative pulmonary complications. We aim to determine factors associated with morbidity and mortality in OLT recipients that required thoracic surgery for pleural space complications. A retrospective review was performed of 42 patients who underwent thoracic surgery after OLT between 2005 and 2015. Preoperative data and postoperative outcomes were reviewed. Time to mortality was summarized using Kaplan-Meier curves. Outcomes associated with 30-day morbidity and mortality as well as long-term mortality were analyzed with univariate analysis. Between 2005 and 2015, 1735 OLTs were performed at our institution. We identified 42 patients who required thoracic surgery. Of these 42 OLT recipients, 33 patients required thoracic surgery for pleural space complications. The median interval between OLT and thoracic surgery for pleural space complications was 5.7 months (interquartile range 2.2-14.1). The most common surgical indications were chronic pleural effusion (n = 12, 36.4%) and empyema (n = 10, 30.3%). The most common thoracic operations were decortication and empyema evacuation. The 30-day morbidity was 69.7%. Bilirubin and empyema were significantly associated with 30-day morbidity (odds ratio [OR] = 2.3, P = 0.023; OR = 16.3, P = 0.015). The 30-day, 1-year, and 5-year mortality rates were 15.2%, 57.6%, and 70.2%, respectively. Vasopressor requirement was significantly associated with 30-day mortality (OR = 10.2, P = 0.031). The development of pleural space complications requiring surgery in OLT recipients suggests a poor prognosis. Hyperbilirubinemia and pleural space infections were associated with high postoperative morbidity in OLT recipients requiring thoracic surgery for pleural space complications.

Diagnostic Value of Quantitative Chest CT Scan in a Case of Spontaneous Pneumothorax.

An 18-year-old woman with no previous medical history presented to an outside hospital facility with acute chest pain. She had mild shortness of breath, particularly with exertion, for the prior 2 months.