Pressure-Dependent Pneumothorax and Air Leak: Physiology and Clinical Implications

Pressure-dependent pneumothorax is a common clinical event, often occurring after pleural drainage in patients with visceral pleural restriction, partial lung resection, or lobar atelectasis from bronchoscopic lung volume reduction or an endobronchial obstruction. This type of pneumothorax and air leak is clinically inconsequential. Failure to appreciate the benign nature of such air leaks may result in unnecessary pleural procedures or prolonged hospital stay. This review suggests that identification of pressure-dependent pneumothorax is clinically important because the air leak that results is not related to a lung injury that requires repair but rather to a physiological consequence of a pressure gradient. A pressure-dependent pneumothorax occurs during pleural drainage in patients with lung-thoracic cavity shape/size mismatch. It is caused by an air leak related to a pressure gradient between the subpleural lung parenchyma and the pleural space. Pressure-dependent pneumothorax and air leak do not need any further pleural interventions.

The Relationship of Pleural Manometry With Postthoracentesis Chest Radiographic Findings in Malignant Pleural Effusion

BACKGROUND

Both elevated pleural elastance (E-P_EL) and radiographic evidence of incomplete lung expansion following thoracentesis have been used to exclude patients with a malignant pleural effusion (MPE) from undergoing pleurodesis. This article reports on a cohort of patients with MPE in whom complete drainage was attempted with pleural manometry to determine the frequency of E-P_EL and its relation with postthoracentesis radiographic findings.

METHODS

Seventy consecutive patients with MPE who underwent therapeutic pleural drainage with pleural manometry were identified. The pressure/volume curves were constructed and analyzed to determine the frequency of E-P_EL and the relation of P_EL to the postthoracentesis chest radiographic findings.

RESULTS

E-P_EL and incomplete lung expansion were identified in 36 of 70 (51.4%) and 38 of 70 (54%) patients, respectively. Patients with normal P_EL had an OR of 6.3 of having complete lung expansion compared with those with E-P_EL (P = .0006). However, 20 of 70 (29%) patients exhibited discordance between postprocedural chest radiographic findings and the pleural manometry results. Among patients who achieved complete lung expansion on the postdrainage chest radiograph, 9 of 32 (28%) had an E-P_EL. In addition, P_EL was normal in 11 of 38 (34%) patients who had incomplete lung expansion as detected according to the postthoracentesis chest radiograph.

CONCLUSIONS

E-P_EL and incomplete lung expansion postthoracentesis are frequently observed in patients with MPE. Nearly one-third of the cohort exhibited discordance between the postprocedural chest radiographic findings and pleural manometry results. These findings suggest that a prospective randomized trial should be performed to compare both modalities (chest radiograph and pleural manometry) in predicting pleurodesis outcome.

Management of Prolonged Pulmonary Air Leaks With Endobronchial Valve Placement

Background:

Prolonged pulmonary air leaks (PALs) are associated with increased morbidity and extended hospital stay. We sought to investigate the role of bronchoscopic placement of 1-way valves in treating this condition.

Methods:

We queried a prospectively maintained database of patients with PAL lasting more than 7 days at a tertiary medical center. Main outcome measures included duration of chest tube placement and hospital stay before and after valve deployment.

Results:

Sixteen patients were eligible to be enrolled from September 2012 through December 2014. One patient refused to give consent, and in 4 patients, the source of air leak could not be identified with bronchoscopic balloon occlusion. Eleven patients (9 men; mean age, 65 ± 15 years) underwent bronchoscopic valve deployment. Eight patients had postoperative PAL and 3 had a secondary spontaneous pneumothorax. The mean duration of air leak before valve deployment was 16 ± 12 days, and the mean number of implanted valves was 1.9 (median, 2). Mean duration of hospital stay before and after valve deployment was 18 and 9 days, respectively (P = .03). Patients who had more than a 50% decrease in air leak on digital monitoring had the thoracostomy tube removed within 3–6 days. There were no procedural complications related to deployment or removal of the valves.

Conclusions:

Bronchoscopic placement of 1-way valves is a safe procedure that could help manage patients with prolonged PAL. A prospective randomized trial with cost-efficiency analysis is necessary to better define the role of this bronchoscopic intervention and demonstrate its effect on air leak duration.

Point-of-Care Echocardiography Improves Assessment of Volume Status in Cirrhosis and Hepatorenal Syndrome

The management of patients with cirrhosis along with acute kidney injury is complex and depends in large part on accurate assessment of intravascular volume status. Assessment of intravascular volume status by point-of-care echocardiography often relies solely on inferior vena cava size and variability evaluation; however, this parameter should be interpretated with an understanding of right ventricular function integrated with stroke volume and flow. Attempts to optimize intra-abdominal hemodynamics favorably are clearly problematic when physical examination findings or rudimentary assessments of central venous pressure or change in central venous pressure are used. Here, we have demonstrated the potential utility of point-of-care echocardiography to optimize the hemodynamic state in patients with decompensated cirrhosis along with acute kidney injury. This case is very unique and describes how this technique may have great promise in optimizing the intra-abdominal hemodynamics and predict the timing of large-volume paracentesis in patients with decompensated cirrhosis, which in turn can aid in promoting favorable renal recovery.

Pleural Fluid Analysis in Chronic Hemothorax: A Mimicker of Infection

OBJECTIVES

Timing to video-assisted thoracoscopic surgery (VATS) in hemothorax is based on preventing acute and long-term complications of retained blood products in the pleural space, including pleural space infection. We propose that the persistence of blood in the pleural space induces a proinflammatory state, independent of active infection.

METHODS

We identified six patients with a hemothorax by clinical history, radiographic imaging, and pleural fluid analysis from a database of 1133 patients undergoing thoracentesis from 2002 to 2010 at the Medical University of South Carolina.

RESULTS

In four of the six patients identified, the time from injury to thoracentesis was one, four, four, and five days, respectively. The fluid pH range was 7.32–7.41. The lactate dehydrogenase (LDH) range was 210–884 IU/L (mean 547 IU/L), and the absolute neutrophil count (ANC) range was 1196–3631 cells/µL. In two patients, the time from injury to thoracentesis was 7 and 60 days. In these two patients, the pH was 7.18 and 6.91, LDH was 1679 and 961 IU/L, and the ANC was 8134 and 5943 cells/µL. Microbiology and pathology were negative in all patients.

CONCLUSIONS

The persistence of blood outside the vascular compartment, and within the pleural space, biochemically mirrors infection. We will explore the multiple mechanisms that account for development of pleural fluid acidosis, inflammation, and neutrophil recruitment.

Improving the predictive accuracy of identifying exudative effusions

BACKGROUND

Application of Light's criteria results in misclassification of some transudative effusions as exudative, particularly because of congestive heart failure (CHF). We sought to determine if the serum to pleural fluid albumin (SF-A) and serum to pleural fluid protein (SF-P) gradients increased the predictive accuracy to correctly identify exudative effusions.

METHODS

We retrospectively analyzed 1,153 consecutive patients who underwent a diagnostic thoracentesis at the Medical University South Carolina. Univariable logistic regression analyses were used to determine the statistical significance of pleural fluid tests that correctly identified exudative effusions. Tests with significant diagnostic accuracy were combined in multivariable logistic regression models, with calculation of areas under the curve (AUCs) to determine their predictive accuracy. The predictive capability of the best model was compared with Light's criteria and other test combinations.

RESULTS

Pleural fluid lactate dehydrogenase (LDH), SF-A gradient, and SF-P gradient had a significant effect on the probability of identifying exudative pleural effusions. When combined together in a multivariable logistic regression, LDH (OR, 14.09 [95% CI, 2.25-85.50]), SF-A gradient (OR, 7.16 [95% CI, 1.24-41.43]), and SF-P gradient (OR, 6.83 [95% CI, 1.56-27.88]) had an AUC of 0.92 (95% CI, 0.85-0.98).

CONCLUSIONS

Application of Light's criteria, not uncommonly, misclassifies CHF transudative effusions as exudates. In cases where no cause for an exudative effusion can be identified or CHF is suspected, the sequential application of the fluid LDH, followed by the SF-P and then the SF-A gradients, may assist in reclassifying pleural effusions as transudates.

Safety of Propofol as an Induction Agent for Urgent Endotracheal Intubation in the Medical Intensive Care Unit

Purpose:

Propofol is known to provide excellent intubation conditions without the use of neuromuscular blocking agents. However, propofol has adverse effects that may limit its use in the critically ill patients, particularly in the hemodynamically unstable patient. We report on the safety and efficacy of propofol for use as an agent for urgent endotracheal intubation (UEI) in the critically ill patients.

Methods:

We reviewed the outcomes of 472 consecutive UEIs performed by a medical intensive care unit (ICU) team at a tertiary care hospital from November 2008 through November 2012. Outcome data were collected prospectively as part of an ongoing quality improvement project.

Results:

Propofol was used as the sole sedative agent in 409 (87%) of the 472 patients. In 18 (4%) of the 472 patients, other agents (midazolam, lorazepam, or etomidate) were used in addition to propofol. Of the 472, 10 (2%) intubations were performed with a sedative agent other than propofol, and 35 (7%) of the 472 intubations were performed without any sedating agent. Endotracheal tube insertion was successful in all 472 patients. Complications of UEI in those patients who received propofol were as follows: desaturation (Sao2 < 80%) 30 (7%) of the 427, hypotension (systolic blood pressure < 70 mm Hg) 19 (4%) of the 427, difficult intubation (>2 attempts) 44 (10%) of the 427, esophageal intubation 24 (6%) of the 427, aspiration 6 (1%) of the 427, and oropharyngeal injury 4 (1%) of the 427. There were no deaths. Average dose of propofol was 99 mg (standard deviation 7.39) per person.

Conclusions:

Our results compare favorably with the complication rate of UEI reported in the critical care and anesthesiology literature and indicate that propofol is a useful agent for airway management in the ICU.

Effects of coexisting pneumonia and end-stage renal disease on pleural fluid analysis in patients with hydrostatic pleural effusion

BACKGROUND

In individual patients, especially those who are hospitalized, several conditions often coexist that may be responsible for the development of a pleural effusion and may affect the pleural fluid analysis (PFA). The objective of this study was to investigate the effects of end-stage renal disease and pneumonia on PFA in patients with hydrostatic pleural effusion.

METHODS

In a retrospective analysis of 1,064 consecutive patients who underwent thoracentesis at a university hospital, cell counts and pleural fluid protein, lactate dehydrogenase, pH, and glucose levels were examined in those (n = 300) with clinical evidence of hydrostatic pleural effusion.

RESULTS

The 300 patients (28.1%) with pleural effusions had congestive heart failure (CHF), circulatory overload (CO), or both. Expert consensus was achieved in 66 (22%) for CHF as the sole diagnosis (SCHF), 30 (10%) for CHF and coexisting pneumonia (PCHF), and 26 (8.7%) for end-stage renal disease (ESRD) with coexisting CO or CHF. The remaining 178 patients were excluded because of complicating conditions. There were minor, but statistically significant differences in pleural fluid/serum protein ratios in patients with ESRD with coexisting CO or CHF compared with SCHF. Compared with SCHF, there were statistically significant tendencies for higher protein and lactate dehydrogenase concentrations and lower pH levels in those with PCHF. The total nucleated cell count and the absolute neutrophil count were significantly higher in PCHF.

CONCLUSIONS

ESRD in patients with hydrostatic pleural effusions has a minimal effect on the PFA. Coexisting pneumonia most often results in an exudative effusion in patients with CHF.

A program to improve the quality of emergency endotracheal intubation

OBJECTIVE

To assess the results of a quality improvement (QI) project designed to improve safety of emergency endotracheal intubation (EEI).

DESIGN

Single center prospective observational.

SETTING

16-bed intensive care unit.

PARTICIPANTS

Nine pulmonary/critical care fellows.

INTERVENTIONS

For 3 years, EEI performed by the medical intensive care unit team were analyzed to identify interventions that would improve quality of the procedure. By segmental process analysis, the procedure of EEI was subjected to iterative change. Major components of process improvement were development of a combined team approach, a mandatory checklist, use of crew resource management (CRM) tactics, and postevent debriefing. Quality analysis and improvement included training of fellows using scenario-based training (SBT) with computerized patient simulator (CPS) to improve mechanical skills of intubation and team leadership. Fellows received 15 sessions of SBT with CPS using a combined checklist and team approach before assuming team leadership position during real-life EEI.

MEASUREMENTS

For a 10-month period, fellows carried digital voice recorders to EEI; which, when combined with recording of continuous oximetry and BP monitoring were used to assess the quality of EEI.

MAIN RESULTS

128 EEI were performed of which 101 had full data recorded. Complications were 14% severe hypoxemia (<80% saturation), 6% severe hypotension (SBP<70 mm Hg), 1% death, 20% difficult EEI (≥ 3 attempts), 11% esophageal intubations, 2% aspiration, and 1% dental injury; 62% EEI were successfully achieved on first attempt, 11% required >3 attempts.

CONCLUSIONS

EEI may be performed by pulmonary/critical medicine (PCCM) fellows with safety comparable to that described in other studies on EEI. Important parts of the program included the use of formal iterative QI approach, the use of intensive SBT with CPS, basic CRM, a comprehensive checklist, and a combined team approach. A key benefit of the program was to make the process of EEI fully transparent for ongoing quality and safety improvement.

Intrapleural therapy

Numerous intrapleural therapies have been adopted to treat a vast array of pleural diseases. The first intrapleural therapies proposed focused on the use of fibrinolytics and DNase to promote fluid drainage in empyema. Numerous case series and five randomized controlled trials have been published to determine the outcomes of fibrinolytics in empyema treatment. In the largest randomized trial, the use of streptokinase had no reduction in mortality, decortication rates or hospital days compared with placebo in the treatment of empyema. Criticism over study design and patient selection may have potentially affected the outcomes in this study. The development of dyspnoea is common in the setting of malignant pleural effusions. Pleural fluid evacuation followed by pleurodesis is often attempted. Numerous sclerosing agents have been studied, with talc emerging as the most effective agent. Small particle size of talc should be avoided because of increased systemic absorption potentiating toxicity, such as acute lung injury. Over the past several years, the use of chronic indwelling pleural catheters have emerged as the preferred modality in the treating a symptomatic malignant pleural effusion. For patients with malignant-related lung entrapment, pleurodesis often fails due to the presence of visceral pleural restriction; however, chronic indwelling pleural catheters are effective in palliation of dyspnoea. Finally, the use of staphylococcal superantigens has been proposed as a therapeutic model for the treatment of non-small lung cancer. Intrapleural instillation of staphylococcal superantigens increased median survival by 5 months in patients with non-small cell lung cancer with a malignant pleural effusion.

Pleural fluid analysis and radiographic, sonographic, and echocardiographic characteristics of hepatic hydrothorax

BACKGROUND

There are limited published data defining complete pleural fluid analysis, echocardiographic characteristics, or the presence or absence of ascites on sonographic or CT imaging in patients with hepatic hydrothorax.

METHODS

We reviewed pleural fluid analysis and radiographic, sonographic, and echocardiographic findings in 41 consecutive patients with hepatic hydrothorax referred to the Pleural Procedure Service for thoracentesis.

RESULTS

Ascites was detected on sonographic or CT imaging in 38 of 39 patients (97%). Diastolic dysfunction was found in 11 of 21 patients (52%). Contrast echocardiography with agitated saline demonstrated an intrapulmonary shunt in 18 of 23 cases (78%). Solitary hepatic hydrothorax had a median pleural fluid pH of 7.49 (fifth to 95th percentile, 7.40-7.57), total protein level of 1.5 g/dL (0.58-2.34), and lactate dehydrogenase (LDH) level of 65 IU/L (36-138). The median pleural fluid/serum protein ratio and pleural LDH/upper limit of normal serum LDH ratio were 0.25 (0.10-0.43) and 0.27 (0.14-0.57), respectively. The median absolute neutrophil count (ANC) was 26 cells/μL (1-230). Only a single patient had a protein discordant exudate despite 83% of patients receiving diuretics. When comparing solitary hepatic hydrothorax and spontaneous bacterial pleuritis, there was no statistically significant difference among pleural fluid total protein (P = .99), LDH (P = .33), and serum albumin (P = .47). ANC was higher in patients with spontaneous bacterial pleuritis (P < .0001).

CONCLUSIONS

Hepatic hydrothorax virtually always presents with ascites that is detectable on sonographic or CT imaging. The development of an "exudate" from diuretic therapy is a rare phenomenon in hepatic hydrothorax. In contrast, diastolic dysfunction and intrapulmonary shunting are common in patients with hepatic hydrothorax. There was no statistically significant change in pleural fluid parameters with spontaneous bacterial pleuritis, except an increased ANC.

Management of pleural effusion in the cancer patient

The differential diagnosis of a pleural effusion is expanded in the cancer patient. A cancer patient may have a malignant pleural effusion, a pleural effusion indirectly caused by the cancer or its treatment, or a pleural effusion unrelated to the cancer. The approach to the cancer patient with a pleural effusion must take into account the impact of the pleural effusion on quality of life, type and stage of the underlying cancer, impact of biopsy procedures on cancer staging, availability of treatment of the underlying cancer, performance status, and patient preferences. Minimally invasive palliative treatment options for the management of symptomatic malignant pleural effusion, such as chronic indwelling pleural catheters, have not only changed the treatment of the effusion but also require a reassessment of what constitutes an adequate diagnostic evaluation prior to considering such treatment options. Of particular concern to the clinician is the cytologically negative exudative pleural effusion for which a cause could not be established after the initial diagnostic evaluation. The decision to proceed to more invasive diagnostic testing must be individualized and the clinician must consider the limitations of histopathological examination of tissue obtained by invasive procedures.

The unexpandable lung

Unexpandable lung is the inability of the lung to expand to the chest wall allowing for normal visceral and parietal pleural apposition. It is the direct result of either pleural disease, endobronchial obstruction resulting in lobar collapse, or chronic atelectasis. Unexpandable lung occurring as a consequence of active or remote pleural disease may present as a post-thoracentesis hydropneumothorax or an effusion that cannot be completely drained because of the development of anterior chest pain. Pleural manometry is useful for identifying unexpandable lung during initial pleural drainage. Unexpandable lung occurring as a consequence of active or remote pleural disease may be separated into two distinct clinical entities termed trapped lung and lung entrapment. Trapped lung is a diagnosis proper and is caused by the formation of a fibrous visceral pleural peel (in the absence of malignancy or active pleural inflammation). The mechanical effect of the pleural peel constitutes the primary clinical problem. Lung entrapment may result from a visceral pleural peel secondary to active pleural inflammation, infection, or malignancy. In these cases, the underlying malignant or inflammatory condition is the primary clinical problem, which may or may not be complicated by unexpandable lung due to visceral pleural involvement. The recognition of trapped lung and lung entrapment as related, but distinct, clinical entities has direct consequences on clinical management. In our practice, pleural manometry is routinely performed during therapeutic thoracentesis and is useful for identification of unexpandable lung and has allowed us to understand the mechanisms surrounding a post-thoracentesis pneumothorax.

Empiric auto-titrating CPAP in people with suspected obstructive sleep apnea

OBJECTIVE

Efficient diagnosis and treatment of obstructive sleep apnea (OSA) can be difficult because of time delays imposed by clinic visits and serial overnight polysomnography. In some cases, it may be desirable to initiate treatment for suspected OSA prior to polysomnography. Our objective was to compare the improvement of daytime sleepiness and sleep-related quality of life of patients with high clinical likelihood of having OSA who were randomly assigned to receive empiric auto-titrating continuous positive airway pressure (CPAP) while awaiting polysomnogram versus current usual care.

METHODS

Serial patients referred for overnight polysomnography who had high clinical likelihood of having OSA were randomly assigned to usual care or immediate initiation of auto-titrating CPAP. Epworth Sleepiness Scale (ESS) scores and the Functional Outcomes of Sleep Questionnaire (FOSQ) scores were obtained at baseline, 1 month after randomization, and again after initiation of fixed CPAP in control subjects and after the sleep study in auto-CPAP patients.

RESULTS

One hundred nine patients were randomized. Baseline demographics, daytime sleepiness, and sleep-related quality of life scores were similar between groups. One-month ESS and FOSQ scores were improved in the group empirically treated with auto-titrating CPAP. ESS scores improved in the first month by a mean of -3.2 (confidence interval -1.6 to -4.8, p < 0.001) and FOSQ scores improved by a mean of 1.5, (confidence interval 0.5 to 2.7, p = 0.02), whereas scores in the usual-care group did not change (p = NS). Following therapy directed by overnight polysomnography in the control group, there were no differences in ESS or FOSQ between the groups. No adverse events were observed.

CONCLUSION

Empiric auto-CPAP resulted in symptomatic improvement of daytime sleepiness and sleep-related quality of life in a cohort of patients awaiting polysomnography who had a high pretest probability of having OSA. Additional studies are needed to evaluate the applicability of empiric treatment to other populations.

American College of Chest Physicians/La Société de Réanimation de Langue Française statement on competence in critical care ultrasonography

OBJECTIVE

To define competence in critical care ultrasonography (CCUS).

DESIGN

The statement is sponsored by the Critical Care NetWork of the American College of Chest Physicians (ACCP) in partnership with La Société de Réanimation de Langue Française (SRLF). The ACCP and the SRLF selected a panel of experts to review the field of CCUS and to develop a consensus statement on competence in CCUS.

RESULTS

CCUS may be divided into general CCUS (thoracic, abdominal, and vascular), and echocardiography (basic and advanced). For each component part, the panel defined the specific skills that the intensivist should have to be competent in that aspect of CCUS.

CONCLUSION

In defining a reasonable minimum standard for CCUS, the statement serves as a guide for the intensivist to follow in achieving proficiency in the field.

Pleural fluid analysis in chylous pleural effusion

OBJECTIVES

Chyle is a noninflammatory, lymphocyte-predominant fluid that may cause a pleural effusion as a consequence of thoracic duct leakage into the pleural space. Although chyle is reported to have protein concentrations in the transudative range, chylous effusions are typically exudative, as defined by the standard criteria. We hypothesized that chylous effusions from a thoracic duct leak alone have low lactate dehydrogenase (LDH) concentrations due to the absence of inflammation and are lymphocyte-predominant, protein-discordant exudates. Consequently, pleural effusions that do not meet these criteria but with triglyceride concentrations of > 110 mg/dL or are positive for chylomicrons should be associated with other diagnoses contributing to pleural fluid formation.

STUDY DESIGN

Retrospective.

METHODS

The pleural fluid analyses of 876 consecutive thoracenteses were reviewed. All cases with a triglyceride concentration of > 110 mg/dL or the presence of chylomicrons were retrieved. The effusions were then classified as transudates, concordant exudates, protein-discordant exudates, and LDH-discordant exudates, and according to lymphocyte predominance (> 50%). The causes of these pleural effusions were determined after the review of the medical record.

RESULTS

Twenty-two pleural effusions had elevated triglyceride concentrations and/or were positive for chylomicrons. Eleven effusions were lymphocyte-predominant, protein-discordant exudates, and two of these were associated with chylous ascites. The remaining effusions were transudates (n = 7) or concordant exudates (n = 4); all were associated with conditions known to cause pleural effusion apart from chyle leakage.

CONCLUSION

Chylous effusions caused solely by conditions known to cause chylothorax were lymphocyte-predominant, protein-discordant exudates. Protein concentrations in the transudative range or elevated LDH concentrations were associated with a coexisting condition that may impact the management of these chylous effusions.

Seat belt-induced chylothorax: a cause of idiopathic chylothorax?

Chylothoraces are associated with multiple etiologies including non-Hodgkin lymphoma and surgical trauma, representing 50% and 25% of all chylothoraces, respectively. Intrathoracic operations such as repair of coarctation of the aorta and esophagectomy are commonly associated with surgical trauma. Idiopathic chylothoraces may account for up to 15% of all chylothoraces. When a thorough evaluation finding is negative, further history to identify possible blunt, nonpenetrating trauma to the chest is warranted.

Endobronchial ultrasound for the diagnosis of pulmonary sarcoidosis

BACKGROUND

The diagnosis of pulmonary sarcoidosis can be established by a variety of techniques. Transbronchial lung biopsy is often the preferred approach, but it is frequently nondiagnostic and carries a risk of pneumothorax and bleeding. Mediastinoscopy is often suggested as the next diagnostic step but entails significant cost and associated morbidity. Endobronchial ultrasound (EBUS) with transbronchial needle aspiration (TBNA) is emerging as a safe, minimally invasive tool for the primary diagnosis of mediastinal and hilar lymphadenopathy. The purpose of this study was to assess the utility of EBUS-TBNA for pulmonary sarcoidosis.

METHODS

Fifty consecutive patients who had been referred for EBUS-TBNA for suspected pulmonary sarcoidosis were included in the study. On-site cytology was used to assess the adequacy of the samples. The presence of noncaseating granulomas without necrosis in the appropriate clinical setting was deemed to be adequate for the diagnosis of pulmonary sarcoidosis. Patients with a negative EBUS-TBNA underwent further histologic biopsy or clinical follow-up to determine the final diagnosis.

RESULTS

Eighty-two lymph nodes with a median size of 16 mm (range, 4 to 40 mm) were punctured. EBUS-TBNA demonstrated noncaseating granulomas without necrosis in 41 of 48 patients (85%) with a final diagnosis of sarcoidosis. EBUS-TBNA, therefore, has a sensitivity of 85% for the primary diagnosis of pulmonary sarcoidosis.

CONCLUSIONS

EBUS-TBNA is a safe, minimally invasive tool for the primary diagnosis of pulmonary sarcoidosis that has a high diagnostic yield. EBUS-TBNA should be considered an appropriate alternative diagnostic technique for patients with suspected pulmonary sarcoidosis.

Characteristics of Trapped Lung

STUDY OBJECTIVES

To review the pleural fluid characteristics, pleural manometry, and radiographic data of patients who received a diagnosis of trapped lung in our pleural diseases service.

DESIGN

Retrospective case series.

METHODS

The procedure records of 247 consecutive patients who underwent pleural manometry at the Medical University of South Carolina between October 2002 and November 2005 were reviewed. Eleven patients in whom a diagnostic pneumothorax was introduced were identified. Manometry data, radiographic findings, pleural fluid analysis, final clinical diagnosis, and information regarding the initial pleural insult were retrieved from the medical record.

RESULTS

All 11 patients had a clinical diagnosis of trapped lung. The causes of trapped lung were attributed to coronary artery bypass graft surgery, uremia, thoracic radiation, pericardiotomy, spontaneous bacterial pleuritis and repeated thoracentesis, and complicated parapneumonic effusion. Mean pleural fluid pH was 7.30, pleural fluid lactate dehydrogenase (LDH) was 124 IU/L, and pleural fluid total protein was 2.9 g/dL. Pleural fluid was paucicellular with mononuclear cell predominance. Pleural space elastance was increased in all cases and ranged from 19 to 149 cm H(2)O/L of pleural fluid removed. All demonstrated abnormal visceral pleural thickness on air-contrast chest CT.

CONCLUSIONS

Trapped lung is a clinical entity characterized by the presence of a restrictive visceral pleural peel that was first described in 1967. The pleural fluid is paucicellular, LDH is low, and protein may be in the exudative range. The elevated total pleural fluid protein may be related to factors other than active pleural inflammation or malignancy and does not exclude the diagnosis.

Effect of thoracentesis on respiratory mechanics and gas exchange in the patient receiving mechanical ventilation

BACKGROUND

This study reports the effect of thoracentesis on respiratory mechanics and gas exchange in patients receiving mechanical ventilation.

STUDY DESIGN

Prospective.

SETTING

University hospital.

PATIENTS

Eight patient receiving mechanical ventilation with unilateral (n = 7) or bilateral (n = 1) large pleural effusions.

INTERVENTION

Therapeutic thoracentesis (n = 9).

MEASUREMENTS

Resistances of the respiratory system measured with the constant inspiratory flow interrupter method measuring peak pressure and plateau pressure, effective static compliance of the respiratory system (Cst,rs), work performed by the ventilator (Wv), arterial blood gases, mixed exhaled Pco2, and pleural liquid pressure (Pliq).

RESULTS

Thoracentesis resulted in a significant decrease in Wv and Pliq. Thoracentesis had no significant effect on dynamic compliance of the respiratory system; Cst,rs; effective interrupter resistance of the respiratory system, or its subcomponents, ohmic resistance of the respiratory system and additional (non-ohmic) resistance of the respiratory system; or intrinsic positive end-expiratory pressure (PEEPi). Indices of gas exchange were not significantly changed by thoracentesis.

CONCLUSIONS

Thoracentesis in patients receiving mechanical ventilatory support results in significant reductions of Pliq and Wv. These changes were not accompanied by significant changes of resistance or compliance or by significant changes in gas exchange immediately after thoracentesis. The reduction of Wv after thoracentesis in patients receiving mechanical ventilation is not accompanied by predictable changes in inspiratory resistance and static compliance measured with routine clinical methods. The benefit of thoracentesis may be most pronounced in patients with high levels of PEEPi.

PRE- AND POSTTHORACENTESIS CHEST RADIOGRAPHIC FINDINGS DO NOT PREDICT ABNORMAL PLEURAL ELASTANCE

STUDY OBJECTIVES

Pneumothorax following ultrasound-guided thoracentesis is rare. Our goal was to explain the mechanisms of pneumothorax following ultrasound-guided thoracentesis in a setting where pleural manometry is routinely used.

METHODS

We reviewed the patient records and procedure reports of 401 patients who underwent ultrasound-guided thoracentesis. When manometry was performed, pleural space elastance was determined. A model assuming dependence of the pleural space elastic properties on respiratory system elastic properties was used to isolate cases with presumed normal pleural space elastance. Elastance outside mean +/- SD x 2 of the isolated sample was considered abnormal. Four radiographic criteria of unexpandable lung were used: visceral pleural peel, lobar atelectasis, basilar pneumothorax, and pneumothorax with ipsilateral shift.

RESULTS

There were 102 diagnostic thoracenteses, 192 therapeutic thoracenteses with pleural manometry, and 73 therapeutic thoracenteses without manometry. There was one pneumothorax that occurred from lung puncture and eight unintentional pneumothoraces, all of which showed radiographic evidence of unexpandable lung. Four of eight unintentional pneumothoraces had abnormal elastance; none had excessively negative pleural pressure (< -25 cm H(2)O).

CONCLUSIONS

Unintentional pneumothoraces cannot be prevented by monitoring for symptoms or excessively negative pressure. These pneumothoraces were drainage related rather than due to penetrating lung trauma or external air introduction. We speculate that unintentional pneumothoraces are caused by transient, parenchymal-pleural fistulae caused by nonuniform stress distribution over the visceral pleura that develop during large-volume drainage if the lung cannot conform to the shape of the thoracic cavity in some patients with unexpandable lung. These fistulae appear to be pressure dependent, and the resulting pneumothoraces rarely require treatment. Drainage-related pneumothorax is an unavoidable complication of ultrasound-guided thoracentesis and appears to account for the vast majority of pneumothoraces occurring in a procedure service.

Pleural effusions in a series of 181 outpatients with sarcoidosis

OBJECTIVES

Pleural effusion (PE) is considered to be a rare manifestation of pulmonary sarcoidosis. We performed thoracic ultrasonography prospectively in consecutive outpatients with sarcoidosis to determine the frequency of PEs caused by sarcoidosis and to define their pleural fluid characteristics.

DESIGN

Consecutive outpatients aged >/= 18 years with biopsy-proven sarcoidosis underwent ultrasonography.

SETTING

University hospital, outpatient sarcoidosis clinic.

RESULTS

One hundred eighty-one outpatients were enrolled into the study. The subjects were predominately African-American and female. Most were between 30 and 60 years of age. The Scadding radiograph stages were fairly evenly distributed across all five stages (0 through 4). Five (2.8%) of 181 patients were found to have pleural fluid. Two patients had a unilateral left-sided PE, and three patients had bilateral PEs. Pleural fluid analysis (PFA) was performed in four patients. The PFA showed a lymphocyte-predominant exudate using protein criterion in only two patients, which is consistent with sarcoidosis-related PE; one patient underwent pleural biopsy, which was consistent with the diagnosis of sarcoidosis. A sarcoidosis-related PE was seen in 1 of 9 patients (11.1%) who had an exacerbation of pulmonary sarcoidosis compared to 1 of 172 patients (0.6%) who did not have an exacerbation (p < 0.4).

CONCLUSION

PEs are rare in outpatients with sarcoidosis, even when a sensitive technique, such as ultrasonography, is used. The frequency of PEs was 2.8% (5 of 181 patients) with only 2 of the 181 PEs (1.1%) caused by sarcoid pleural involvement. PE in patients with sarcoidosis should not be assumed to be related to sarcoidosis. Discordance between levels of pleural fluid total protein and lactate dehydrogenase may be a characteristic finding in patients with sarcoid PE. An exacerbation of pulmonary sarcoidosis was not an independent risk factor for the development of sarcoid-related PE.

Pleural manometry

The goals of therapeutic thoracentesis are to remove the maximum amount of pleural fluid to improve dyspnea and to facilitate the diagnostic evaluation of large pleural effusions. Pleural manometry may be useful for immediately detecting an unexpandable lung, which may coexist when any pleural fluid accumulates. Pleural manometry may improve patient safety when removing large amounts of pleural fluid. The basics of pleural space mechanics are discussed as they apply to the normal pleural space and to pleural effusion associated with expandable and unexpandable lung. This article also discusses the instrumentation required to perform bedside manometry, how manometry may decrease the risk of re-expansion pulmonary edema when large amounts of fluid are removed, and the diagnostic capabilities of manometry.

Pleural Ultrasonography

Ultrasonography has achieved acceptance as a routine clinical tool for clinicians managing pleural disease. This article provides an overview of the field of pleural ultrasonography with an emphasis on clinical applicability and procedure guidance.