Effect of thoracentesis on pulmonary gas exchange

Ultrasound in predicting improvement in dyspnoea after therapeutic thoracentesis in patients with recurrent unilateral pleural effusion

Background

In patients with recurrent pleural effusion, therapeutic thoracentesis is one way of relief. Correct prediction of which patients will experience relief following drainage may support the management of these patients. This study aimed to assess the association between ultrasound (US) characteristics and a relevant improvement in dyspnoea immediately following drainage.

Methods

In a prospective, observational study, patients with recurrent unilateral pleural effusion underwent US evaluation of effusion characteristics and diaphragm movement measured by M-mode and the Area method before and right after drainage. The level of dyspnoea was assessed using the modified Borg scale (MBS). A minimal important improvement in dyspnoea was defined as delta MBS ≥ 1.

Results

In the 104 patients included, 53% had a minimal important improvement in dyspnoea following thoracentesis. We found no association between US-characteristics, including diaphragm shape or movement (M-mode or the Area method), and a decrease in dyspnoea following drainage. Baseline MBS score ≥ 4 and a fully drained effusion were significant correlated with a minimal important improvement in dyspnoea (OR 3.86 (1.42-10.50), p = 0.01 and 2.86 (1.03-7.93), p = 0.04, respectively).

Conclusions

In our study population, US-characteristics including assessment of diaphragm movement or shape was not associated with a minimal important improvement in dyspnoea immediately following thoracentesis.

Malignant pleural disease

Malignant pleural disease represents a growing healthcare burden. Malignant pleural effusion affects approximately 1 million people globally per year, causes disabling breathlessness and indicates a shortened life expectancy. Timely diagnosis is imperative to relieve symptoms and optimise quality of life, and should give consideration to individual patient factors. This review aims to provide an overview of epidemiology, pathogenesis and suggested diagnostic pathways in malignant pleural disease, to outline management options for malignant pleural effusion and malignant pleural mesothelioma, highlighting the need for a holistic approach, and to discuss potential challenges including non-expandable lung and septated effusions.

Breathlessness with Pleural Effusion: What Do We Know?

Breathlessness is the most common symptom in individuals with pleural effusion and is often disabling. The pathophysiology of breathlessness associated with pleural effusion is complex. The severity of breathlessness correlates weakly with the size of the effusion. Improvements in ventilatory capacity following pleural drainage are small and correlate poorly with the volume of fluid drained and improvements in breathlessness. Impaired hemidiaphragm function and a compensatory increase in respiratory drive to maintain ventilation appear to be an important mechanism of breathlessness associated with pleural effusion. Thoracocentesis reduces diaphragm distortion and improves its movement; these changes appear to reduce respiratory drive and associated breathlessness by improving the neuromechanical efficiency of the diaphragm.

Ipsilateral and contralateral hemidiaphragm dynamics in symptomatic pleural effusion: The 2nd PLeural Effusion And Symptom Evaluation (PLEASE-2) Study

BACKGROUND AND OBJECTIVE

The pathophysiology of breathlessness in pleural effusion is unclear. In the PLEASE-1 study, abnormal ipsilateral hemidiaphragm shape and movement, assessed qualitatively, were independently associated with breathlessness relief after pleural drainage. Effects of pleural effusion on contralateral hemidiaphragm function are unknown. PLEASE-2, a prospective exploratory pilot study, assessed the effects of unilateral effusion and drainage on both hemidiaphragms using advanced quantitative bedside ultrasonography.

METHODS

Individuals with symptomatic unilateral pleural effusion undergoing therapeutic drainage were included. Measurements pre- and post-drainage included severity of breathlessness (visual analogue scale) and ultrasound measurements of diaphragm excursion and thickness, in addition to shape and movement. Diaphragm measurements were compared to published reference values.

RESULTS

Twenty participants were recruited (mean age 68.9 [SD 12.8] years, 12 females). During tidal breathing, contralateral hemidiaphragm excursion exceeded ipsilateral excursion and reference values (all p ≤ 0.001). Contralateral excursion was greatest in participants with abnormal ipsilateral hemidiaphragm movement and was inversely correlated with ipsilateral tidal excursion (r = -0.676, p = 0.001). Following drainage (mean volume 2121 [SD = 1206] ml), abnormal shape (n = 12) and paradoxical movement (n = 9) of the ipsilateral hemidiaphragm resolved in all participants, and tidal excursion of the contralateral hemidiaphragm normalized. Relief of breathlessness post-drainage correlated with improvement in ipsilateral hemidiaphragm excursion (r = 0.556, p = 0.031).

CONCLUSION

This pilot study suggests, for the first time, that unilateral pleural effusion not only impairs ipsilateral hemidiaphragm function but also causes compensatory hyperactivity of the contralateral hemidiaphragm, which resolves post-drainage. These findings provide a basis for detailed studies of diaphragmatic function and ventilatory drive in patients with symptomatic pleural effusion.

Anatomy and Applied Physiology of the Pleural Space

The unique anatomy and physiology of the pleural space provides tight regulation of liquid within the space under normal physiologic conditions. When this balance is disrupted and pleural effusions develop, there can be significant impacts on the respiratory system. Drainage of effusions can lead to meaningful improvement in symptoms, primarily owing to improvement in the length-tension relationship of the respiratory muscles. Ultrasound examination to evaluate the movement and function of the diaphragm, as well as pleural manometry, have provided a greater understanding of the impact of pleural effusion and thoracentesis.

The Impact of Thoracentesis On Postprocedure Pulse Oximetry

BACKGROUND

Although thoracentesis can offer considerable symptomatic relief to the patient, its physiologic impact on oxygen saturation has not been well established in the literature. This study aimed to evaluate the impact of thoracentesis on postprocedure pulse oximetry (SpO2) in an inpatient population.

METHODS

A retrospective study of patients undergoing thoracentesis from January 2012 to November 2017 was performed. Inclusion criteria were age above 18 and thoracentesis performed in an inpatient setting. Records were reviewed for patient demographics, procedure reports, and laboratory values. SpO2 and FiO2 values were collected before and 6 and 24 hours postprocedure. Multivariable linear regression models were used to evaluate for changes in SpO2 and SpO2/FiO2. Analyses were adjusted for age, sex, serum hemoglobin, effusion etiology, volume removed, nonexpandable lung physiology and procedural complications and FiO2.

RESULTS

A total of 502 patients were included. The mean (SD) age was 60 (14) years, and 53.4% of the patients were male. The most common cause of pleural effusion was malignant effusion (37%). The median (interquartile range) volume of fluid removed was 1400 (1000 to 2000) mL and nonexpandable lung physiology was noted in 35%. There was no significant within-subject difference in 24 hours postprocedure SpO2 compared with preprocedure SpO2. In multivariable analysis, there was a small increase in 24-hour postprocedure SpO2 [β=0.31, 95% confidence interval (0.22, 0.41), P<0.01] and a similar small increase in 24-hour postprocedure SpO2/FiO2 [β=0.84, 95% confidence interval: (0.68, 1.01), P<0.01).

CONCLUSION

Among inpatients undergoing thoracentesis, there is no clinically significant change in SpO2 or SpO2/FiO2 at 24-hours post-procedure compared to pre-procedural SpO2 or SpO2/FiO2.

Drainage of transudative pleural effusion: how does it affect weaning from mechanical ventilation?

Background

Pleural collections of the transudative type occur frequently in patients who need mechanical ventilation (MV). Treatment of the etiology of the effusion takes a prolonged duration of time. The study intended to assess the effect of transudative effusion drainage through chest tube on the process of weaning from MV.

Results

No statistically significant difference was found between the two studied groups regarding age, sex, and comorbidities. Total duration of MV was significantly shorter in patients of group I compared with patients of group II (P = 0.002). Successful weaning from MV within 2 days after the start of the study was statistically significantly more achieved in patients of group I (56.7%) compared with patients of group II (23.3%) (P = 0.017). One and 3 days after beginning of the study, patients in group I showed a significant improvement in oxygenation as demonstrated by a statistically significantly higher value of PaO2/FiO2 ratio compared with patients of group II (P = 0.003 and 0.008, respectively).

Conclusion

More work is needed to determine the physiological benefits of transudate pleural effusion drainage and the effect of the specific procedure on the clinical parameters. Further studies are needed to study different modalities or tools of drainage of transudate effusion and the effect of each on the different clinical outcomes in comparison with each other to reach the optimum way of drainage of transudate effusion with the best results and least complications.

The Pleural Effusion And Symptom Evaluation (PLEASE) study of breathlessness in patients with a symptomatic pleural effusion

INTRODUCTION

Pathophysiology changes associated with pleural effusion, its drainage and factors governing symptom response are poorly understood. Our objective was to determine: 1) the effect of pleural effusion (and its drainage) on cardiorespiratory, functional and diaphragmatic parameters; and 2) the proportion as well as characteristics of patients with breathlessness relief post-drainage.

METHODS

Prospectively enrolled patients with symptomatic pleural effusions were assessed at both pre-therapeutic drainage and at 24-36 h post-therapeutic drainage.

RESULTS

145 participants completed pre-drainage and post-drainage tests; 93% had effusions ≥25% of hemithorax. The median volume drained was 1.68 L. Breathlessness scores improved post-drainage (mean visual analogue scale (VAS) score by 28.0±24 mm; dyspnoea-12 (D12) score by 10.5±8.8; resting Borg score before 6-min walk test (6-MWT) by 0.6±1.7; all p<0.0001). The 6-min walk distance (6-MWD) increased by 29.7±73.5 m, p<0.0001. Improvements in vital signs and spirometry were modest (forced expiratory volume in 1 s (FEV₁) by 0.22 L, 95% CI 0.18-0.27; forced vital capacity (FVC) by 0.30 L, 95% CI 0.24-0.37). The ipsilateral hemi-diaphragm was flattened/everted in 50% of participants pre-drainage and 48% of participants exhibited paradoxical or no diaphragmatic movement. Post-drainage, hemi-diaphragm shape and movement were normal in 94% and 73% of participants, respectively. Drainage provided meaningful breathlessness relief (VAS score improved ≥14 mm) in 73% of participants irrespective of whether the lung expanded (mean difference 0.14, 95% CI 10.02-0.29; p=0.13). Multivariate analyses found that breathlessness relief was associated with significant breathlessness pre-drainage (odds ratio (OR) 5.83 per standard deviation (sd) decrease), baseline abnormal/paralyzed/paradoxical diaphragm movement (OR 4.37), benign aetiology (OR 3.39), higher pleural pH (OR per sd increase 1.92) and higher serum albumin level (OR per sd increase 1.73).

CONCLUSIONS

Breathlessness and exercise tolerance improved in most patients with only a small mean improvement in spirometry and no change in oxygenation. Breathlessness improvement was similar in participants with and without trapped lung. Abnormal hemi-diaphragm shape and movement were independently associated with relief of breathlessness post-drainage.

The use of a virtual patient to follow changes in arterial blood gases associated with therapeutic thoracentesis

PURPOSES:

Some controversies exist on the effect of therapeutic thoracentesis (TT) on arterial blood oxygen tension. The aim of this study was to evaluate this issue using a previously developed virtual patient.

METHODS:

The analysis was based and supported by clinical data collected during 36 TT. Pleural pressure and transcutaneous oxygen and carbon dioxide pressures (PtcO₂ and PtcCO₂) were measured during pleural fluid withdrawal. Arterial blood oxygen tension and arterial CO₂ tension (PaO₂ and PaCO₂) were analysed in simulations that mimicked TT. Minute ventilation was adjusted to maintain arterial CO₂ tension at a constant level unless arterial blood oxygen tension fell below 8 kPa. Specifically, the influence of hypoxic pulmonary vasoconstriction efficiency was tested.

RESULTS:

In patients, PtcCO₂ remained at an approximately constant level (average amplitude: 0.63 ± 0.29 kPa), while some fluctuations of PtcO2 were observed (amplitude: (1.65 ± 1.18 kPa) were observed. In 42% of patients, TT was associated with decrease in PtcCO₂. Simulations showed the following: (a) there were similar PaO₂ fluctuations in the virtual patient; (b) the lower the hypoxic pulmonary vasoconstriction efficiency, the more pronounced the PaO₂ fall during fluid withdrawal; and (c) the lower the atelectatic lung areas recruitment rate, the slower the PaO₂ normalization. The decrease in PaO₂ was caused by an increase of pulmonary shunt.

CONCLUSION:

Therapeutic thoracentesis may cause both an increase and a decrease in PaO₂ during the procedure. Pleural pressure decrease, caused by pleural fluid withdrawal, improves the perfusion of atelectatic lung areas. If the rate of recruitment of these areas is low, a lack of ventilation causes the arterial blood oxygen tension to fall. Effective hypoxic pulmonary vasoconstriction may protect against the pulmonary shunt.

Patterns of pleural pressure amplitude and respiratory rate changes during therapeutic thoracentesis

BACKGROUND

Although the impact of therapeutic thoracentesis on lung function and blood gases has been evaluated in several studies, some physiological aspects of pleural fluid withdrawal remain unknown. The aim of the study was to assess the changes in pleural pressure amplitude (Ppl_ampl) during the respiratory cycle and respiratory rate (RR) in patients undergoing pleural fluid withdrawal.

METHODS

The study included 23 patients with symptomatic pleural effusion. Baseline pleural pressure curves were registered with a digital electronic manometer. Then, the registrations were repeated after the withdrawal of consecutive portions of pleural fluid (200 ml up to 1000 ml and 100 ml above 1000 ml). In all patients the pleural pressure curves were analyzed in five points, at 0, 25%, 50%, 75% and 100% of the relative volume of pleural effusion withdrawn in particular patients.

RESULTS

There were 11 and 12 patients with right sided and left sided pleural effusion, respectively (14 M, 9F, median age 68, range 46-85 years). The most common cause of pleural effusion were malignancies (20 pts., 87%). The median total volume of withdrawn pleural fluid was 1800 (IQR 1500-2400) ml. After termination of pleural fluid withdrawal Ppl_ampl increased in 22/23 patients compared to baseline. The median Ppl_ampl increased from 3.4 (2.4-5.9) cmH₂O to 10.7 (8.1-15.6) cmH₂O (p < 0.0001). Three patterns of Ppl_ampl changes were identified. Although the patterns of RR changes were more diversified, a significant increase between RR at baseline and the last measurement point was found (p = 0.0097).

CONCLUSIONS

In conclusion, therapeutic thoracentesis is associated with significant changes in Ppl_ampl during the respiratory cycle. In the vast majority of patients Ppl_ampl increased steadily during pleural fluid withdrawal. There was also an increase in RR. The significance of these changes should be elucidated in further studies.

TRIAL REGISTRATION

ClinicalTrial.gov, registration number: NCT02192138 , registration date: July 1st, 2014.

State of the art thoracic ultrasound: intervention and therapeutics

The use of thoracic ultrasound outside the radiology department and in everyday clinical practice is becoming increasingly common, having been incorporated into standards of care for many specialties. For the majority of practitioners, their experience of, and exposure to, thoracic ultrasound will be in its use as an adjunct to pleural and thoracic interventions, owing to the widely recognised benefits for patient safety and risk reduction. However, as clinicians become increasingly familiar with the capabilities of thoracic ultrasound, new directions for its use are being sought which might enhance practice and patient care. This article reviews the ways in which the advent of thoracic ultrasound is changing the approach to the investigation and treatment of respiratory disease from an interventional perspective. This will include the impact of thoracic ultrasound on areas including patient safety, diagnostic and therapeutic procedures, and outcome prediction; and will also consider potential future research and clinical directions.

Thoracentesis

Pleural effusions are common and account for high morbidity and mortality in a range of patients. Thoracentesis can provide significant symptom relief and improvement in physiologic parameters including dyspnea, exercise, and sleep. Recent advances, including the use of ultrasound and dedicated procedural teams, have improved the safety of thoracentesis. This has allowed thoracentesis to be performed on higher-risk individuals including those with elevated bleeding risk and bilateral pleural effusions. This review will summarize recent advances in thoracentesis procedural safety, symptom relief following thoracentesis, and understanding of the physiologic basis for such improvements.

Physiology of breathlessness associated with pleural effusions

PURPOSE OF REVIEW

Pleural effusions have a major impact on the cardiorespiratory system. This article reviews the pathophysiological effects of pleural effusions and pleural drainage, their relationship with breathlessness, and highlights key knowledge gaps.

RECENT FINDINGS

The basis for breathlessness in pleural effusions and relief following thoracentesis is not well understood. Many existing studies on the pathophysiology of breathlessness in pleural effusions are limited by small sample sizes, heterogeneous design and a lack of direct measurements of respiratory muscle function. Gas exchange worsens with pleural effusions and improves after thoracentesis. Improvements in ventilatory capacity and lung volumes following pleural drainage are small, and correlate poorly with the volume of fluid drained and the severity of breathlessness. Rather than lung compression, expansion of the chest wall, including displacement of the diaphragm, appears to be the principle mechanism by which the effusion is accommodated. Deflation of the thoracic cage and restoration of diaphragmatic function after thoracentesis may improve diaphragm effectiveness and efficiency, and this may be an important mechanism by which breathlessness improves. Effusions do not usually lead to major hemodynamic changes, but large effusions may cause cardiac tamponade and ventricular diastolic collapse. Patients with effusions can have impaired exercise capacity and poor sleep quality and efficiency.

SUMMARY

Pleural effusions are associated with abnormalities in gas exchange, respiratory mechanics, respiratory muscle function and hemodynamics, but the association between these abnormalities and breathlessness remains unclear. Prospective studies should aim to identify the key mechanisms of effusion-related breathlessness and predictors of improvement following pleural drainage.

CT volumetric analysis of pleural effusions: a comparison with thoracentesis volumes

RATIONALE AND OBJECTIVES

The primary objective of this study was to compare computed tomography (CT) volumetric analysis of pleural effusions with thoracentesis volumes. The secondary objective of this study was to compare subjective grading of pleural effusion size with thoracentesis volumes.

MATERIALS AND METHODS

This was a retrospective study of 67 patients with free-flowing pleural effusions who underwent therapeutic thoracentesis. CT volumetric analysis was performed on all patients; the CT volumes were compared with the thoracentesis volumes. In addition, the subjective grading of pleural effusion size was compared with the thoracentesis volumes.

RESULTS

The average difference between CT volume and thoracentesis volume was 9.4 mL (1.3%) ± 290 mL (30%); these volumes were not statistically different (P = .79, paired two-tailed Student's t-test). The thoracentesis volume of a "small," "moderate," and "large" pleural effusion, as graded on chest CT, was found to be approximately 410 ± 260 cc, 770 ± 270 mL and 1370 ± 650 mL, respectively; the thoracentesis volume of a "small," "moderate," and "large" pleural effusion, as graded on chest radiograph, was found to be approximately 610 ± 320 mL, 1040 ± 460 mL, and 1530 ± 830 mL, respectively.

CONCLUSIONS

CT volumetric analysis is an accessible tool that can be used to accurately quantify the size of pleural effusions.

The effects of pleural fluid drainage on respiratory function in mechanically ventilated patients after cardiac surgery

Background

Pleural effusions occur commonly after cardiac surgery and the effects of drainage on gas exchange in this population are not well established. We examined pulmonary function indices following drainage of pleural effusions in cardiac surgery patients.

Methods

We performed a retrospective study examining the effects of pleural fluid drainage on the lung function indices of patients recovering from cardiac surgery requiring mechanical ventilation for more than 7 days. We specifically analysed patients who had pleural fluid removed via an intercostal tube (ICT: drain group) compared with those of a control group (no effusion, no ICT).

Results

In the drain group, 52 ICTs were sited in 45 patients. The mean (SD) volume of fluid drained was 1180 (634) mL. Indices of oxygenation were significantly worse in the drain group compared with controls prior to drainage. The arterial oxygen tension (PaO₂)/fractional inspired oxygen (FiO₂) (P/F) ratio improved on day 1 after ICT placement (mean (SD), day 0: 31.01 (8.92) vs 37.18 (10.7); p<0.05) and both the P/F ratio and oxygenation index (OI: kPa/cm H₂O=PaO₂/mean airway pressure×FiO₂) demonstrated sustained improvement to day 5 (P/F day 5: 39.85 (12.8); OI day 0: 2.88 (1.10) vs day 5: 4.06 (1.73); both p<0.01). The drain group patients were more likely to have an improved mode of ventilation on day 1 compared with controls (p=0.028).

Conclusions

Pleural effusion after cardiac surgery may impair oxygenation. Drainage of pleural fluid is associated with a rapid and sustained improvement in oxygenation.

Symptom relief after large-volume thoracentesis in the absence of lung perfusion

The physiologic basis for relief from dyspnea after therapeutic thoracentesis remains poorly understood. Here, we describe the case of a 46-year-old man with large recurrent pleural effusion with absent perfusion to the affected lung who experienced dramatic dyspnea relief after large-volume thoracentesis. This patient's improvement in breathlessness cannot be attributed to improved gas exchange and suggests the primary physiologic basis for the relief in dyspnea is a change in respiratory system mechanics or work of breathing.

Drainage of pleural effusion in mechanically ventilated patients: time to measure chest wall compliance?

PURPOSE

Pleural effusion (PE) is commonly encountered in mechanically ventilated, critically ill patients and is generally addressed with evacuation or by fluid displacement using increased airway pressure (P(AW)). However, except when massive or infected, clear evidence is lacking to guide its management. The aim of this study was to investigate the effect of recruitment maneuvers and drainage of unilateral PE on respiratory mechanics, gas exchange, and lung volume.

MATERIALS AND METHODS

Fifteen critically ill and mechanically ventilated patients with unilateral PE were enrolled. A 3-step protocol (baseline, recruitment, and effusion drainage) was applied to patients with more than 400 mL of PE, as estimated by chest ultrasound. Predefined subgroup analysis compared patients with normal vs reduced chest wall compliance (C(CW)). Esophageal and P(AW)s, respiratory system, lung and C(CW)s, arterial blood gases, and end-expiratory lung volumes were recorded.

RESULTS

In the whole case mix, neither recruitment nor drainage improved gas exchange, lung volume, or tidal mechanics. When C(CW) was normal, recruitment improved lung compliance (81.9 [64.8-104.1] vs 103.7 [91.5-111.7] mL/cm H2O, P < .05), whereas drainage had no significant effect on total respiratory system mechanics or gas exchange, although it measurably increased lung volume (1717 vs 2150 mL, P < .05). In the setting of reduced C(CW), however, recruitment had no significant effect on total respiratory system mechanics or gas exchange, whereas pleural drainage improved respiratory system and C(CW)s as well as lung volume (42.7 [38.9-50.0] vs 47.0 [43.8-63.3], P < .05 and 97.4 [89.3-97.9] vs 126.7 [92.3-153.8] mL/cm H2O, P < .05 and 1580 vs 1750 mL, P < .05, respectively).

CONCLUSIONS

Drainage of a moderate-sized effusion should not be routinely performed in unselected population of critically ill patients. We suggest that measurement of C(CW) may help in the decision-making process.

Pleural effusions on the intensive care unit; hidden morbidity with therapeutic potential

Despite 50-60% of intensive care patients demonstrating evidence of pleural effusions, there has been little emphasis placed on the role of effusions in the aetiology of weaning failure. Critical illness and mechanical ventilation lead to multiple perturbations of the normal physiological processes regulating pleural fluid homeostasis, and consequently, failure of normal pleural function occurs. Effusions can lead to deleterious effects on respiratory mechanics and gas exchange, and when extensive, may lead to haemodynamic compromise. The widespread availability of bedside ultrasound has not only facilitated earlier detection of pleural effusions but also safer fluid sampling and drainage. In the majority of patients, pleural drainage leads to improvements in lung function, with data from spontaneously breathing individuals demonstrating a consistent symptomatic improvement, while a meta-analysis in critically ill patients shows an improvement in oxygenation. The effects on respiratory mechanics are less clear, possibly reflecting heterogeneity of underlying pathology. Limited data on clinical outcome from pleural fluid drainage exist; however, it appears to be a safe procedure with a low risk of major complications. The current level of evidence would support a clinical trial to determine whether the systematic detection and drainage of pleural effusions improve clinical outcomes.

Pleural effusion in patients with acute lung injury: a CT scan study

OBJECTIVES

Pleural effusion is a frequent finding in patients with acute respiratory distress syndrome. To assess the effects of pleural effusion in patients with acute lung injury on lung volume, respiratory mechanics, gas exchange, lung recruitability, and response to positive end-expiratory pressure.

DESIGN, SETTING, AND PATIENTS

A total of 129 acute lung injury or acute respiratory distress syndrome patients, 68 analyzed retrospectively and 61 prospectively, studied at two University Hospitals.

INTERVENTIONS

Whole-lung CT was performed during two breath-holding pressures (5 and 45 cm H2O). Two levels of positive end-expiratory pressure (5 and 15 cm H2O) were randomly applied.

MEASUREMENTS

Pleural effusion volume was determined on each CT scan section; respiratory system mechanics, gas exchange, and hemodynamics were measured at 5 and 15 cm H2O positive end-expiratory pressure. In 60 patients, elastances of lung and chest wall were computed, and lung and chest wall displacements were estimated.

RESULTS

Patients were divided into higher and lower pleural effusion groups according to the median value (287 mL). Patients with higher pleural effusion were older (62±16 yr vs. 54±17 yr, p<0.01) with a lower minute ventilation (8.8±2.2 L/min vs. 10.1±2.9 L/min, p<0.01) and respiratory rate (16±5 bpm vs. 19±6 bpm, p<0.01) than those with lower pleural effusion. Both at 5 and 15 cm H2O of positive end-expiratory pressure PaO2/FIO2, respiratory system elastance, lung weight, normally aerated tissue, collapsed tissue, and lung and chest wall elastances were similar between the two groups. The thoracic cage expansion (405±172 mL vs. 80±87 mL, p<0.0001, for higher pleural effusion group vs. lower pleural effusion group) was greater than the estimated lung compression (178±124 mL vs. 23±29 mL, p<0.0001 for higher pleural effusion group vs. lower pleural effusion group, respectively).

CONCLUSIONS

Pleural effusion in acute lung injury or acute respiratory distress syndrome patients is of modest entity and leads to a greater chest wall expansion than lung reduction, without affecting gas exchange or respiratory mechanics.

Pleural effusion: diagnosis, treatment, and management

A pleural effusion is an excessive accumulation of fluid in the pleural space. It can pose a diagnostic dilemma to the treating physician because it may be related to disorders of the lung or pleura, or to a systemic disorder. Patients most commonly present with dyspnea, initially on exertion, predominantly dry cough, and pleuritic chest pain. To treat pleural effusion appropriately, it is important to determine its etiology. However, the etiology of pleural effusion remains unclear in nearly 20% of cases. Thoracocentesis should be performed for new and unexplained pleural effusions. Laboratory testing helps to distinguish pleural fluid transudate from an exudate. The diagnostic evaluation of pleural effusion includes chemical and microbiological studies, as well as cytological analysis, which can provide further information about the etiology of the disease process. Immunohistochemistry provides increased diagnostic accuracy. Transudative effusions are usually managed by treating the underlying medical disorder. However, a large, refractory pleural effusion, whether a transudate or exudate, must be drained to provide symptomatic relief. Management of exudative effusion depends on the underlying etiology of the effusion. Malignant effusions are usually drained to palliate symptoms and may require pleurodesis to prevent recurrence. Pleural biopsy is recommended for evaluation and exclusion of various etiologies, such as tuberculosis or malignant disease. Percutaneous closed pleural biopsy is easiest to perform, the least expensive, with minimal complications, and should be used routinely. Empyemas need to be treated with appropriate antibiotics and intercostal drainage. Surgery may be needed in selected cases where drainage procedure fails to produce improvement or to restore lung function and for closure of bronchopleural fistula.

Sleep in patients with large pleural effusion: impact of thoracentesis

PURPOSE

This study aimed to evaluate the sleep quality and impact of thoracentesis on sleep in patients with a large pleural effusion.

METHODS

Patients with large unilateral pleural effusion were evaluated by the Pittsburgh Sleep Quality Index (PSQI) questionnaire and dyspnea Borg scale. Full polysomnography (PSG) was performed on the night before and 36 h after thoracentesis.

RESULTS

We studied 19 patients, 11 males and 8 females, age 55 ± 18 years and body mass index of 26 ± 5 kg/m(2). The baseline sleep quality was poor (PSQI = 9.1 ± 3.5). Thoracentesis removed 1.624 ± 796 mL of pleural fluid and resulted in a significant decrease in dyspnea Borg scale (2.3 ± 2.1 vs. 0.8 ± 0.9, p < 0.001). The PSG before and after thoracentesis showed no significant change in apnea-hypopnea index and sleep time with oxygen saturation <90%. There was a significant improvement in sleep efficiency (76% vs. 81%, p = 0.006), decrease percent sleep stage 1 (16% vs. 14%, p = 0.002), and a trend improvement in total sleep time (344 ± 92 vs. 380 ± 69 min, p = 0.056) and percentage of rapid eye movement sleep (15% vs. 20%, p = 0.053). No significant changes occurred in six patients that performed two consecutive PSG before thoracentesis. The improvement in sleep quality was not associated with the volume of pleural fluid withdrawn or changes in dyspnea.

CONCLUSIONS

Patients with large pleural effusion have poor subjective and objective sleep quality that improves after thoracentesis.

Utility and safety of draining pleural effusions in mechanically ventilated patients: a systematic review and meta-analysis

INTRODUCTION

Pleural effusions are frequently drained in mechanically ventilated patients but the benefits and risks of this procedure are not well established.

METHODS

We performed a literature search of multiple databases (MEDLINE, EMBASE, HEALTHSTAR, CINAHL) up to April 2010 to identify studies reporting clinical or physiological outcomes of mechanically ventilated critically ill patients who underwent drainage of pleural effusions. Studies were adjudicated for inclusion independently and in duplicate. Data on duration of ventilation and other clinical outcomes, oxygenation and lung mechanics, and adverse events were abstracted in duplicate independently.

RESULTS

Nineteen observational studies (N = 1,124) met selection criteria. The mean PaO2:FiO2 ratio improved by 18% (95% confidence interval (CI) 5% to 33%, I2 = 53.7%, five studies including 118 patients) after effusion drainage. Reported complication rates were low for pneumothorax (20 events in 14 studies including 965 patients; pooled mean 3.4%, 95% CI 1.7 to 6.5%, I2 = 52.5%) and hemothorax (4 events in 10 studies including 721 patients; pooled mean 1.6%, 95% CI 0.8 to 3.3%, I2 = 0%). The use of ultrasound guidance (either real-time or for site marking) was not associated with a statistically significant reduction in the risk of pneumothorax (OR = 0.32; 95% CI 0.08 to 1.19). Studies did not report duration of ventilation, length of stay in the intensive care unit or hospital, or mortality.

CONCLUSIONS

Drainage of pleural effusions in mechanically ventilated patients appears to improve oxygenation and is safe. We found no data to either support or refute claims of beneficial effects on clinically important outcomes such as duration of ventilation or length of stay.

Pleural space elastance and changes in oxygenation after therapeutic thoracentesis in ventilated patients with heart failure and transudative pleural effusions

BACKGROUND AND OBJECTIVE

Therapeutic thoracentesis (TT) is required in patients with refractory pleural effusions and impaired oxygenation. In this study, the relationship between pleural space elastance (PE) and changes in oxygenation after TT was investigated in ventilated patients with heart failure and transudative pleural effusions.

METHODS

Twenty-six mechanically ventilated patients with heart failure and significant transudative effusions, who were undergoing TT, were studied. The effusion was drained as completely as possible, with monitoring of pleural liquid pressure (Pliq) and chest symptoms. The volume of effusion removed, the changes in Pliq during TT, PE and arterial blood gases before and after TT were recorded.

RESULTS

The mean volume of effusion removed was 1011.9 +/- 58.2 mL. The mean Pliq decreased from 14.5 +/- 1.0 to 0.1 +/- 1.5 cm H(2)O after TT, and the mean PE was 15.3 +/- 1.8 cm H(2)O/L. TT significantly increased the mean ratio of PaO(2)/fraction of inspired oxygen (FiO(2)) from 243.2 +/- 19.9 to 336.0 +/- 17.8 mm Hg (P < 0.0001). The changes in PaO(2)/FiO(2) ratio after TT were inversely correlated with PE (r = -0.803, P < 0.0001). The 14 patients (54%) with normal PE (<or=14.5 cm H(2)O/L) had significantly greater increases in PaO(2)/FiO(2) ratio after TT than did the 12 patients with abnormal PE (>14.5 cm H(2)O/L).

CONCLUSIONS

Measurement of PE during TT may be valuable for predicting improvement in oxygenation in ventilated patients with heart failure and pleural effusions. Patients with lower PE showed greater improvement in oxygenation after TT.

Sustained effects of thoracocentesis on oxygenation in mechanically ventilated patients

BACKGROUND AND OBJECTIVE

No consensus exists as to the benefit of pleural drainage in mechanically ventilated patients with conflicting data concerning the effects on gas exchange. We determined the effects on gas exchange over a 48-hour period of draining, by thoracocentesis, large volume pleural effusions.

METHODS

A total of 15 thoracocenteses were performed in 10 mechanically ventilated patients with ultrasound evidence of pleural effusions predicted to be greater than 800 mL in volume. Gas exchange, mixed expired CO2, dynamic lung compliance, ventilator settings before procedure and at 30 min, 4, 8, 24 and 48 h were determined. Data were analysed using paired t-tests and repeated-measure anova.

RESULTS

Following thoracocentesis there was a 40% increase in the PaO(2) from 82.0 +/- 10.6 mm Hg to 115.2 +/- 31.1 mm Hg (P < 0.05) with a 34% increase in the P:F ratio from 168.9 +/- 55.9 mm Hg to 237.8 +/- 72.6 mm Hg (P < 0.05). These effects were maintained for a period of 48 h. There was a correlation between the amount of fluid drained and the effects on oxygenation with an increase in the PaO(2) of 4 mm Hg for each 100 mL of pleural fluid drained. A-a gradients continued to improve over the course of the study together with a reduction in the dead space fraction and improved dynamic compliance.

CONCLUSIONS

Drainage of large pleural effusions in mechanically ventilated patients leads to a significant improvement in gas exchange, and these effects are sustained for 48 h after the procedure supporting a role in the discontinuation of mechanical ventilation.

Pleural fluid analysis of lung cancer vs benign inflammatory disease patients

BACKGROUND

Correct diagnosis of pleural effusion (PE) as either benign or malignant is crucial, although conventional cytological evaluation is of limited diagnostic accuracy, with relatively low sensitivity rates.

METHODS

We identified biological markers accurately detected in a simple PE examination. We analysed data from 19 patients diagnosed with lung cancer (nine adeno-Ca, five non-small-cell Ca (not specified), four squamous-cell Ca, one large-cell Ca) and 22 patients with benign inflammatory pathologies: secondary to trauma, pneumonia or TB.

RESULTS

Pleural effusion concentrations of seven analysed biological markers were significantly lower in lung cancer patients than in benign inflammatory patients, especially in matrix metalloproteinase (MMP)-9, MMP-3 and CycD1 (lower by 65% (P<0.000003), 40% (P<0.0007) and 34% (P<0.0001), respectively), and in Ki67, ImAnOx, carbonyls and p27. High rates of sensitivity and specificity values were found for MMP-9, MMP-3 and CycD1: 80 and 100%; 87 and 73%; and 87 and 82%, respectively.

CONCLUSION

Although our results are of significant merit in both the clinical and pathogenetic aspects of lung cancer, further research aimed at defining the best combination for marker analysis is warranted. The relative simplicity in analysing these markers in any routine hospital laboratory may result in its acceptance as a new diagnostic tool.

Surgical and other invasive approaches to recurrent pleural effusion with malignant etiology

With an increasing number of cancer survivors, the annual incidence of malignant pleural effusions has been rising in recent decades worldwide. Many patients with various forms of cancer develop malignant pleural effusions at some point in their life. Patients most commonly present with progressive dyspnea. These effusions are refractory and are associated with impaired quality of life for these patients. The main goals of management are evacuation of the pleural fluid and prevention of its re-accumulation. The therapy plan should consider the general health of the patients, their performance status, the presence of trapped lung, and the primary malignancy. However, there is no universally established, standard approach. Surgical options include thoracentesis, chest tube drainage, thoracoscopy followed by chemical and mechanical pleurodesis, Pleur-X catheter drainage, and pleurectomy. Chemical pleurodesis is the most common modality of therapy for patients with recurrent pleural effusion. For example, Talc is the most successful pleurodesis agent with similar equal to that of poudrage or slurry. Pleur-X catheter can reduce hospital stay and adds value to the treatment of patients with trapped lung, who are not appropriate candidates for pleurodesis. Furthermore, a mechanical pleurodesis has been shown to be effective particularly in pleural effusions with lower pH. This article reviews the surgical and other invasive options as well as their technical aspects in the management of recurrent malignant pleural effusions.

Improved lung function after thoracocentesis in patients with paradoxical movement of a hemidiaphragm secondary to a large pleural effusion

BACKGROUND AND OBJECTIVES

Previous studies have shown little or no improvement in pulmonary function and arterial blood oxygenation after therapeutic thoracocentesis. This study investigated changes in pulmonary function, arterial blood gases and dyspnoea after therapeutic thoracocentesis in patients with paradoxical movement (PM) of a hemidiaphragm due to pleural effusion.

METHODS

Twenty-one patients with pleural effusion and PM of a hemidiaphragm and 41 patients with pleural effusion but without paradoxical movement (NPM) were studied before and 24 h after thoracocentesis. Lung function measurements included lung mechanics, blood gas exchange and the Borg dyspnoea scale.

RESULTS

At thoracocentesis a mean of 1,220 mL of pleural fluid was removed from the PM group and 1,110 mL from the NPM group. Post-thoracocentesis the PM group showed small but significant improvement (P < 0.05) in FEV(1) (63% vs 73%), FVC (67% vs 77%), PaO(2) (66 mm Hg vs 73 mm Hg), A-a O(2) gradient (38 mm Hg vs 30 mm Hg), and the Borg scale (5.1 vs 2.1). The NPM group showed no significant change in any parameter.

CONCLUSIONS

Statistically significant improvement in pulmonary function following thoracocentesis was observed in patients with pleural effusion and PM of the hemidiaphragm. Patient selection may therefore explain the different outcomes of thoracocentesis reported in previous studies.

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.

Malignant pleural effusion, current and evolving approaches for its diagnosis and management

Malignant pleural effusion is a common and debilitating complication of advanced malignant diseases. This problem seems to affect particularly those with lung and breast cancer, contributing to the poor quality of life. Approximately half of all patients with metastatic cancer develop a malignant pleural effusion at some point, which is likely to cause significant symptoms such as dyspnea and cough. Evacuation of the pleural fluid and prevention of its re-accumulation are the main goals of management. Optimal treatment is controversial and there is no universally standard approach. Intervention options range from observation in the case of asymptomatic effusions through simple thoracentesis to more invasive methods such as chemical and mechanical pleurodesis, pleur-X catheter drainage, pleuroperitoneal shunting, and pleurectomy. The best results are reported with thoracoscopy and talc insufflation, with an acceptable morbidity. Development of novel methods to control malignant pleural effusion should be a high priority in palliative care of cancer patients. This article reviews the current, as well as, novel approaches that show some promise for the future. The aim is to identify the proper approach for each individual patient.

Persistent hypoxia after diagnosis and treatment of pulmonary thromboembolism

Acute respiratory failure in the perioperative period represents a frequent challenge to the anesthesiologist. The differential diagnosis is extensive and includes alterations on the pulmonary parenchyma, pulmonary vessels, airway, and cardiac system. Occasionally, two or more pathophysiological process superimpose. We present a patient who suffered from a left pulmonary embolism that was appropriately diagnosed and treated. However, the hypoxemia persisted and a second pathology was suspected. After careful evaluation and differential diagnosis, we drained a right pleural effusion, which had been present preoperatively, with resolution of the hypoxemia. There is controversy in the literature as to the role of drainage of pleural effusions on improving oxygenation. We present this case as an example of successful management of perioperative respiratory failure by thoracentesis in the presence of a second concurrent pathologic process.

Use of an implantable pleural catheter for trapped lung syndrome in patients with malignant pleural effusion

STUDY OBJECTIVES

We describe a series of patients with symptomatic, refractory malignant pleural effusion (MPE) and underlying trapped lung syndrome who underwent placement of a small-bore, flexible indwelling pleural catheter for home drainage of recurrent MPE.

DESIGN

The medical records of 11 consecutive patients who underwent pleural catheter placement for MPE with trapped lung syndrome were reviewed retrospectively.

SETTING

Patients were evaluated and followed up in the Pulmonary Outpatient Practice at the Hospital of the University of Pennsylvania.

PATIENTS

Nine men and two women with underlying malignancies including lung cancer, lymphoma, and mesothelioma underwent pleural catheter placement.

INTERVENTIONS

Thirteen pleural catheters were placed in 11 patients, all under local anesthesia. Patients received detailed instructions for drainage and catheter care. They were reevaluated weekly for the first 2 weeks, and then as clinically indicated. Patients typically performed pleural drainage at home up to 1,000 mL two or three times weekly.

MEASUREMENTS AND RESULTS

All patients reported symptomatic benefit, defined as improved dyspnea and exercise tolerance, except for one patient. In 10 patients, the pleural catheters remained in place until death, for 15 to 234 days. The mean length of placement was 115 days. One patient required revision after catheter occlusion. Other complications included catheter infection, localized skin breakdown, and possible cellulitis.

CONCLUSION

We have described a series of patients with MPE and trapped lung syndrome for whom placement of a permanent pleural catheter provided a convenient, effective alternative to the procedures currently in use. Our patients reported good symptomatic relief following catheter placement with few major complications.

Radioisotope scintigraphy in the diagnosis of hepatic hydrothorax

BACKGROUND

Pleural effusion in cirrhotic patients (hepatic hydrothorax) may result from migration of ascitic fluid across defects in the diaphragm. Biochemical analysis of ascitic and pleural fluid provides only indirect information about the nature and origin of the effusion. The present study was performed in order to demonstrate the presence/absence of peritoneo-pleural communication by radioisotope imaging.

METHODS

Ten patients with cirrhotic ascites and pleural effusion were studied with 99mTc sulfur colloid scintigraphy to look for movement of the radiotracer from the peritoneal to the pleural cavity. Serum-ascitic albumin gradient (SAAG) and serum-pleural fluid albumin gradient (SPAG) values were determined in eight patients to examine the nature of the ascitic and pleural fluids.

RESULTS

Transdiaphragmatic movement of ascitic fluid into the pleural space was demonstrated (generally within 2 h of intraperitoneal injection of the radiotracer) in eight of 10 patients; six on the right side, one on the left and one bilaterally. Two patients in whom pleural fluid was transudative on SPAG values were negative for peritoneo-pleural communications.

CONCLUSIONS

Radionuclide scintigraphy is a simple, safe and relatively non-invasive method to confirm passage of ascitic fluid across the diaphragm.

Pleural complications in the intensive care unit

In summary pleural complications in the ICU are common. Pneumothorax in a mechanically ventilated patient is a medical emergency that requires prompt diagnosis and therapy. Correct diagnosis and therapy of pleural effusions will assist in improving pulmonary physiology and outcome in the ICU patient.

The effect of thoracentesis on lung function and transthoracic electrical bioimpedance

This study aimed to determine the relationship between improvement in lung function and changes in transthoracic electrical bioimpedance (TEB) after thoracentesis in patients with pleural effusions. Fifteen patients with pleural effusions due to either malignant (n = 8) or cardiac (n = 7) diseases were included. Pulmonary function was assessed before and after thoracentesis. During thoracentesis the patients were monitored with TEB. Using linear correlation analysis, the increases for each litre of aspirated thoracic fluid were: forced expiratory volume in 1 s (FEV1) 0.261; forced vital capacity (FVC) 0.331; total lung capacity (TLC) 0.58; and the lung diffusing capacity (DLCO); 2.4 ml min-1 mmHg-1. Baseline impedance increased by 2.3 Ohm l-1 aspirated thoracic fluid. The relative increase in baseline impedance was twice as high for patients with cancer as for patients with heart failure (P < 0.05). We found only minor changes in systolic blood pressure and mean arterial pressure. The improvements in diffusing capacity, airflow, and lung volumes after thoracentesis are correlated to an increase in baseline impedance, but changes are dependent on the primary disease.

Ventilation-perfusion mismatch in patients with pleural effusion: effects of thoracentesis

Pleural effusion (PE) often causes abnormal pulmonary gas exchange. Thoracentesis is commonly used to relieve dyspnea in patients with PE, but its effect upon arterial oxygenation is varied and poorly understood. This investigation sought to: (1) characterize the distribution of ventilation-perfusion (VA/Q) ratios in patients with PE and (2) assess the effects of PE drainage by thoracentesis upon pulmonary gas exchange. We studied nine patients (two females) with a mean age of 39+/-20 (SD) yr. All of them had PE of recent clinical onset (< 2 wk of symptoms), without other apparent medical conditions. Before thoracentesis, PaO2 was 82.3+/-10.2 mm Hg and AaPO2 was 28.7+/-10.0 mm Hg. Patients had broadened unimodal VA/Q distributions with small amounts of blood flow perfusing lung units with low VA/Q ratios (< 0.1) (1.4+/-2.2%) and mild intrapulmonary shunt (6.9+/-6.7%). PaO2 was significantly related to the amount of shunt (rho = -0.82; p < 0.01) but not to the percentage of blood flow perfusing low VA/Q units. While thoracentesis drained 693+/-424 ml of fluid and caused a significant fall in mean pleural pressure (by -10.7 +/- 7.1 mm Hg; p < 0.01), PaO2, AaPO2, and shunt remained unchanged; only the amount of blood flow perfusing low VA/Q ratios increased slightly (2.4+/-2.6%; p < 0.05). This study shows that: (1) intrapulmonary shunt is the main mechanism underlying arterial hypoxemia in patients with PE and (2) effective thoracentesis has minor short-term effects upon pulmonary gas exchange. These findings are in accord with delayed (> 30 min) pulmonary volume re-expansion after thoracentesis with or without the coexistence of mild ex vacuo pulmonary edema.

Changes in pulmonary mechanics and gas exchange after thoracentesis on patients with inversion of a hemidiaphragm secondary to large pleural effusion

The present study was designed to test whether there was a significant improvement in pulmonary function and arterial blood oxygenation after therapeutic thoracentesis on patients with inversion of a hemidiaphragm due to pleural effusion. In 21 patients with inversion of a hemidiaphragm because of a pleural effusion, we studied the changes in pulmonary mechanics and gas exchange that occurred in 24 h after removal of 600 to 2,700 mL of fluid by thoracentesis. There was a small but significant increase in the forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) (p < 0.001). The alveolar-arterial oxygen gradient (P[A-a]O2) and partial pressure of arterial oxygen (PaO2) showed a significant increase (p < 0.001), but there was no change in partial pressure of arterial carbon dioxide (PaCO2). In the present study, all patients with a large pleural effusion had inversion of a hemidiaphragm documented by chest sonography, and that was an important factor to observe significant improvement in pulmonary mechanics and gas exchange.

Pulmonary aspects of chronic liver disease and liver transplantation

A vast spectrum of pulmonary pathologic conditions occurs in association with chronic liver diseases, and clinically important manifestations, such as arterial hypoxemia, can result. Both pulmonary vascular and parenchymal abnormalities can contribute to the dysfunction, as evidenced by results of pulmonary function tests and gas exchange studies. The clinical implications of identifying such pulmonary problems range from alleviation of symptoms, especially dyspnea, to comprehensive assessment of patients before and after liver transplantation. Physicians should be aware of these potential pulmonary disorders that can complicate liver disease and liver transplantation so that management of affected patients can be improved.