Vascular endothelial growth factor levels in post-CABG pleural effusions are associated with pleural inflammation and permeability.

BACKGROUND: Vascular endothelial growth factor (VEGF) participates in the pathogenesis of exudative pleural effusions (PEs). In the present study, we determined the pleural fluid (PF) and serum VEGF levels in patients with post-coronary artery by-pass grafting (post-CABG) PEs. METHODS: Thirty-eight patients with post-CABG (two with bilateral) PEs were studied. PEs were divided into "early" (occurring earlier than 30 days after surgery) and "late" ones. VEGF levels were measured using ELISA. RESULTS: (i) Serum and PF VEGF levels did not differ significantly when all the patients (P=0.053) or those with late effusions (P=0.6) were analyzed; serum VEGF levels were significantly elevated in comparison to PF VEGF levels in patients with early (P=0.007) effusions. (ii) Serum VEGF levels were significantly higher in patients with early than in those with late effusions (P=0.033), while PF VEGF levels were not significantly different between the two groups (P=0.77). (iii) PF VEGF levels were higher than corresponding serum levels in 4/24 patients with early and in 10/16 patients with late post-CABG PEs (P=0.006). (iv) In PEs VEGF levels significantly correlated with red blood cells (P=0.015), nucleated cells (P=0.003), protein levels (P=0.002) and lactate dehydrogenase (LDH) levels (P=0.04). CONCLUSION: In post-CABG PEs, preferential local production of VEGF in the pleural cavity is most commonly observed a month or later after surgery. The fact that in PEs VEGF levels correlate with markers of pleural inflammation (inflammatory cells and LDH levels) and vascular hyperpermeability (protein levels) suggests that VEGF may be involved in the pathogenesis of post-CABG PEs.

Prevalence and characteristics of pleural effusions in superior vena cava syndrome.

OBJECTIVE AND BACKGROUND: The prevalence and characteristics of pleural effusions occurring in adults with the superior vena cava (SVC) syndrome are unknown. The purpose of the present study was to characterize these pleural effusions. METHODS: Charts of patients diagnosed with SVC syndrome at a tertiary care referral centre were reviewed. Radiographs were evaluated for the presence and size of pleural effusions, presence and location of masses and mediastinal width. If a pleural effusion was present, the patient's chart and a pre-existing database on pleural effusions were searched to determine whether the effusion was sampled and the results of any laboratory investigations on the fluid. RESULTS: The SVC syndrome occurred in 78 patients. Malignancy was the aetiology in 60% of the cases and bronchogenic carcinoma was the most common malignancy. An intravascular device was the aetiology in the majority of benign cases. Pleural effusion was found in 70% of patients with a malignant aetiology and 58% of those with a benign cause (P=0.345). The mean size of the effusions was larger in malignant cases (P=0.012). Of the 44 effusions 22 were sampled (17 in malignancy and five with benign processes); none was transudates, 20 (91%) were exudative (four of these were chylous) and the remaining two were reported as exudates but did not have pleural chemistries documented. CONCLUSIONS: More than half of patients with SVC syndrome have pleural effusions, regardless of the aetiology. However, the effusions are larger when associated with malignancy. The majority of these effusions are exudative and occasionally chylous. None was transudates.

Eotaxin-3 and interleukin-5 pleural fluid levels are associated with pleural fluid eosinophilia in post-coronary artery bypass grafting pleural effusions.

OBJECTIVES: The primary aim of this study was to examine the association between pleural fluid (PF) eosinophilia, and the PF and serum levels of interleukin (IL)-5, eotaxin-2, eotaxin-3, and vascular cell adhesion molecule (VCAM)-1 in patients with post-coronary artery bypass grafting (CABG) pleural effusions. DESIGN: A prospective observational study. SETTING: A tertiary teaching hospital. PATIENTS AND METHODS: Thirty-eight patients with post-CABG pleural effusions were recruited into the study. An effusion that contained at least 10% eosinophils was called "eosinophilic." The PF and serum levels of the cytokines and VCAM-1 were measured using an enzyme-linked immunosorbent assay. RESULTS: (1) The number of PF eosinophils significantly correlated with the number of blood eosinophils. (2) PF IL-5 levels were significantly higher than the corresponding serum levels, and there was a significant correlation between the PF and serum IL-5 levels. PF IL-5 levels significantly correlated with the PF eosinophil count, and serum IL-5 levels significantly correlated with the number of blood eosinophils. (3) PF eotaxin-3 levels were significantly higher than serum levels, and PF eotaxin-3 levels significantly correlated with the PF eosinophil count. (4) PF VCAM-1 levels were significantly lower than the corresponding serum levels, and PF VCAM-1 levels were significantly higher in eosinophilic pleural effusions (EPEs) than in non-EPEs. CONCLUSION: In patients with post-CABG pleural effusions, IL-5 and eotaxin-3 are produced preferentially in the pleural cavity, and they are strongly associated with PF eosinophilia.

Continuous oxygen monitoring--a better way to prescribe long-term oxygen therapy.

STUDY OBJECTIVE: The purpose of this study was to determine if an oxygen prescription based on continuous oximetry monitoring, would result in an increased percentage of time spent within an SpO2 level between 88% and 92%. METHODS: We conducted a prospective, cohort study in an outpatient, pulmonary setting in a tertiary care referral center, on 17 patients with stable chronic obstructive pulmonary disease (COPD) who had previously been prescribed long-term oxygen therapy. The patients were monitored for approximately 24h with a portable oximeter that recorded SpO2 and EKG readings. During the initial 24h of monitoring, the patients were on their previous oxygen prescription. Their oxygen prescription was then altered based on a predetermined protocol described below. The patients were then monitored for an additional 24h. RESULTS: Sixteen patients completed the study. Based on the initial continuous oximetry, the median oxygen prescription was reduced from 2.5 to 1.2 L/min (P < 0.001). The oxygen prescription during exercise, rest, and sleep decreased from 3.0 +/- 0.9 to 1.8 +/- 1.3 L/min (P < 0.001), 2.2+/-0.4 to 0.8 +/- 0.7 L/min (P < 0.001), and 2.2 +/- 0.4 to 0.9 +/- 0.8 L/min (P < 0.001) respectively. After the oxygen prescription was adjusted, the percentage of the time that the SpO2 was between 88 and 92% increased from 24.8 +/- 21.7% to 52.8 +/- 25.0% (P = 0.001), but the percentage of time that the SpO2 was below 88% did not change significantly (2.8 +/- 6.1% to 4.3 +/- 8.1%). CONCLUSIONS: This study demonstrates that an oxygen prescription based on continuous oximetry monitoring results in (1) a significant increase in the percentage of time that the SpO2 is between 88% and 92%, (2) a significant decrease in the amount of oxygen prescribed, (3) a slight increase in the amount of time that the SpO2 is below 88% that was not statistically significant.

Stability of adenosine deaminase during transportation.

STUDY OBJECTIVE: Measurement of pleural fluid adenosine deaminase (ADA) levels is useful in the differential diagnosis of pleural effusions. However, at ambient temperatures, the levels of this enzyme decline with time. The purpose of the present study was to identify, test, and optimize additives that stabilize ADA, consequently eliminating the need for dry ice or other cold specimen transport media. DESIGN: A preliminary screen of historically proven stabilizing agents for specific proteins demonstrated effectiveness of glycerol for maintenance of pleural fluid ADA levels. Systematic studies for exploitation of the glycerol effect included the following: (1) supplements to the glycerol of promising alternate compounds, (2) long-term stability studies at ambient and elevated temperatures, (3) a field test of an effective mixture as a means for reduction of specimen transport costs, (4) thermal stability studies for optimization of the agents for use at otherwise denaturing temperatures, and (5) inclusion of pleural fluids from patients with a variety of etiologies, including tuberculous pleurisy, in order to gauge the effectiveness of the stabilizing agents on both the high and low molecular weight forms of ADA. RESULTS: A mixture of glycerol and ethylene glycol, each at 5% concentration, maintained pleural fluid ADA levels for at least 21 days at both room temperatures and 37 degrees C. A field test of 32 pleural fluids found that ADA levels in specimens containing this mixture, sent to the laboratory by surface mail at ambient temperatures, were nearly identical to those in aliquots of the same fluids shipped over dry ice. The bias in the measurement was 0.49 IU/L, with a precision of 2.49 IU/L. The correlation coefficient between the two measurements was 0.97. Thermal stability studies found that tuberculous pleural fluids containing 10% glycerol and 0.10 mol/L sodium sulfate maintained constant ADA levels for at least 10 days at 45 degrees C, an otherwise denaturing temperature for nonstabilized specimens. CONCLUSION: The addition of stabilizing agents to pleural fluid specimens allows the transport of those specimens to distant laboratories at ambient temperatures without a decline in the ADA levels. Employment of those agents will decrease the cost of the test and facilitate its use in second- and third-world countries.

Pleural fluid levels of vascular cell adhesion molecule-1 are elevated in eosinophilic pleural effusions.

STUDY OBJECTIVES: The mechanisms responsible for the accumulation of eosinophils in pleural fluid are not fully understood. The objective of the present study was to examine the relationship between pleural fluid eosinophilia and the levels of vascular cell adhesion molecule (VCAM)-1, eotaxin, RANTES (regulated upon activation, normal T-cell expressed and secreted), and interleukin (IL)-4 in pleural effusions. PATIENTS AND METHODS: Thirty-one patients with eosinophilic pleural effusion (EPE) [eosinophil percentage > 10% of the pleural fluid nucleated cells] and 10 patients without EPE were evaluated. VCAM-1, eotaxin, RANTES, and IL-4 in all pleural fluids were measured using enzyme-linked immunosorbent assay kits. IL-5 levels of the same fluids were measured in a previous study. RESULTS: VCAM-1, eotaxin, and RANTES but not IL-4 were detectable in the pleural fluids. The mean level of VCAM-1 in EPE (336 +/- 85 ng/mL) was significantly higher (p = 0.011) than that in the noneosinophilic effusions (260 +/- 34 ng/mL) [mean +/- SD]. VCAM-1 levels were significantly correlated with the eosinophil count and percentage in all pleural fluids (r = 0.43, p = 0.005, and r = 0.37, p = 0.019, respectively). Multiple linear regression analysis disclosed that both IL-5 (beta, 0.63; p < 0.001) and VCAM-1 (beta, 0.27, p = 0.025) are independent predictors of the number of eosinophils in all pleural fluids. RANTES and eotaxin did not differ significantly between EPEs and non-EPEs, and were not correlated with the number of pleural fluid eosinophils. CONCLUSION: The levels of VCAM-1 are increased in EPE, suggesting that VCAM-1 is important in the pathogenesis of EPE. Neither eotaxin nor RANTES is associated with pleural fluid eosinophilia.

Patient with bilateral pleural effusion: are the findings the same in each fluid?

STUDY OBJECTIVES: To determine whether, in patients with bilateral pleural effusions, the main cellular and biochemical features of the pleural fluid on the right side differ from or correlate with those on the left side. We examined lactate dehydrogenase (LDH), glucose, and total protein (TP) levels, RBC count, nucleated cell count (NCC), and differential cell count. PATIENTS AND METHODS: Twenty-seven patients with bilateral pleural effusions, including 13 patients with effusions after coronary artery bypass graft surgery, 12 patients with congestive heart failure, 1 patient with malignant pericarditis, and 1 patient with renal failure, were studied retrospectively. RESULTS: The right-sided and the left-sided pleural effusions did not differ in the mean TP (p = 0.38), glucose (p = 0.31), and LDH (p = 0.39) levels, RBC count (p = 0.31), NCC (p = 0.96), and the percentage of neutrophils (p = 0.22), lymphocytes (p = 0.73), mononuclear cells (MNCs) [p = 0.49], and eosinophils (p = 0.65). The bias +/- precision was 0.1 +/- 0.64 g/dL for TP, - 2.7 +/- 23 mg/dL for glucose, 41 +/- 362 IU/L for LDH, 6,100 +/- 62,900 cells/ micro L for RBC count, - 36 +/- 1,043 cells/ micro L for NCC, - 2.9 +/- 11.6% for the percentage of neutrophils, 1.15 +/- 17% for the percentage of lymphocytes, 2.3 +/- 17% for the percentage of the MNCs, and - 0.15 +/- 5.4% for the percentage of eosinophils. Moreover, there was a close correlation between the right-sided and the left-sided pleural effusions concerning TP level (r = 0.85, p < 0.001), glucose level (r = 0.78, p < 0.001), LDH level (r = 0.71, p < 0.001), RBC count (r = 0.66, p < 0.001), NCC (r = 0.60, p = 0.001), and the percentage of neutrophils (r = 0.77, p < 0.001), lymphocytes (r = 0.77, p < 0.001), MNCs (r = 0.74, p < 0.001), and eosinophils (r = 0.84, p < 0.001). CONCLUSION: Since the pleural fluid findings tend to be similar in both sides of patients with bilateral pleural effusion, we suggest that diagnostic thoracentesis may not need to be performed on both sides, unless there is a specific clinical indication.