PET-CT-guided versus CT-guided biopsy in suspected malignant pleural thickening: a randomised trial.

BACKGROUND: Pleural biopsy is the gold standard for diagnosis of pleural malignancy but a significant proportion will have an inconclusive biopsy despite ongoing clinical suspicion of malignancy. We investigated whether positron emission tomography-computed tomography (PET-CT) targeted pleural biopsy is superior to standard CT-guided pleural biopsy following an initial non-diagnostic biopsy. METHODS: The TARGET trial was a multicentre, parallel group randomised trial. Patients with a previous inconclusive pleural biopsy but an ongoing suspicion of pleural malignancy were randomised (1:1) to receive either CT-guided biopsy (standard care) or PET-CT followed by a targeted CT biopsy (intervention). The primary outcome was pleural malignancy correctly identified from the trial biopsy. RESULTS: Between September 2015 and September 2018, 59 participants were randomised from eight UK hospital sites: 29 to CT-only followed by targeted biopsy and 30 to PET-CT followed by targeted biopsy. The proportion of pleural malignancy correctly identified was similar between the groups (risk ratio 1.03 (95% CI 0.83-1.29); p=0.77). The sensitivity of the trial biopsy to identify pleural malignancy was 79% (95% CI 54-94%) in the CT-only group versus 81% (95% CI 54-96%) in the PET-CT group. CONCLUSIONS: The results do not support the practice of PET-CT to guide pleural biopsies in patients with a previous non-diagnostic biopsy. The diagnostic sensitivity in the CT-only group was higher than anticipated and supports the practice of repeating a CT-guided biopsy following an inconclusive result if clinical suspicion of malignancy persists.

Bacteriophages for bronchiectasis: treatment of the future?

PURPOSE OF REVIEW: Bronchiectasis is a chronic respiratory disease characterized by dilated airways, persistent sputum production and recurrent infective exacerbations. The microbiology of bronchiectasis includes various potentially pathogenic microorganisms including Pseudomonas aeruginosa which is commonly cultured from patients' sputum. P. aeruginosa is difficult to eradicate and frequently exhibits antimicrobial resistance. Bacteriophage therapy offers a novel and alternative method to treating bronchiectasis and can be used in conjunction with antibiotics to improve patient outcome. RECENT FINDINGS: Thirteen case reports/series to date have successfully used phages to treat infections in bronchiectasis patients, however these studies were constrained to few patients ( n  = 32) and utilized personalized phage preparations and adjunct antibiotics. In these studies, phage therapy was delivered by inhalation, intravenously or orally and was well tolerated in most patients without any unfavourable effects. Favourable clinical or microbiological outcomes were seen following phage therapy in many patients. Longitudinal patient follow-up reported regrowth of bacteria and phage neutralization in some studies. There are five randomized clinical controlled trials ongoing aiming to use phage therapy to treat P. aeruginosa associated respiratory conditions, with limited results available to date. SUMMARY: More research, particularly robust clinical trials, into how phages can clear respiratory infections, interact with resident microbiota, and how bacteria might develop resistance will be important to establish to ensure the success of this promising therapeutic alternative.

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.

A randomised controlled trial of intrapleural balloon intercostal chest drains to prevent drain displacement.

BACKGROUND: Chest drain displacement is a common clinical problem that occurs in 9-42% of cases and results in treatment failure or additional pleural procedures conferring unnecessary risk. A novel chest drain with an integrated intrapleural balloon may reduce the risk of displacement. METHODS: A prospective randomised controlled trial comparing the balloon drain to standard care (12 F chest drain with no balloon) with the primary outcome of objectively defined unintentional or accidental chest drain displacement. RESULTS: 267 patients were randomised (primary outcome data available in 257, 96.2%). Displacement occurred less frequently using the balloon drain (displacement 5 of 128, 3.9%; standard care displacement 13 of 129, 10.1%) but this was not statistically significant (OR for drain displacement 0.36, 95% CI 0.13-1.0, Chi-squared 1 degree of freedom (df)=2.87, p=0.09). Adjusted analysis to account for minimisation factors and use of drain sutures demonstrated balloon drains were independently associated with reduced drain fall-out rate (adjusted OR 0.27, 95% CI 0.08-0.87, p=0.028). Adverse events were higher in the balloon arm than the standard care arm (balloon drain 59 of 131, 45.0%; standard care 18 of 132, 13.6%; Chi-squared 1 df=31.3, p<0.0001). CONCLUSION: Balloon drains reduce displacement compared with standard drains independent of the use of sutures but are associated with increased adverse events specifically during drain removal. The potential benefits of the novel drain should be weighed against the risks, but may be considered in practices where sutures are not routinely used.

Randomized Controlled Trial of Urokinase versus Placebo for Nondraining Malignant Pleural Effusion.

RATIONALE: Patients with malignant pleural effusion experience breathlessness, which is treated by drainage and pleurodesis. Incomplete drainage results in residual dyspnea and pleurodesis failure. Intrapleural fibrinolytics lyse septations within pleural fluid, improving drainage. OBJECTIVES: To assess the effects of intrapleural urokinase on dyspnea and pleurodesis success in patients with nondraining malignant effusion. METHODS: We conducted a prospective, double-blind, randomized trial. Patients with nondraining effusion were randomly allocated in a 1:1 ratio to intrapleural urokinase (100,000 IU, three doses, 12-hourly) or matched placebo. MEASUREMENTS AND MAIN RESULTS: Co-primary outcome measures were dyspnea (average daily 100-mm visual analog scale scores over 28 d) and time to pleurodesis failure to 12 months. Secondary outcomes were survival, hospital length of stay, and radiographic change. A total of 71 subjects were randomized (36 received urokinase, 35 placebo) from 12 U.K. centers. The baseline characteristics were similar between the groups. There was no difference in mean dyspnea between groups (mean difference, 3.8 mm; 95% confidence interval [CI], -12 to 4.4 mm; P = 0.36). Pleurodesis failure rates were similar (urokinase, 13 of 35 [37%]; placebo, 11 of 34 [32%]; adjusted hazard ratio, 1.2; P = 0.65). Urokinase was associated with decreased effusion size visualized by chest radiography (adjusted relative improvement, -19%; 95% CI, -28 to -11%; P < 0.001), reduced hospital stay (1.6 d; 95% CI, 1.0 to 2.6; P = 0.049), and improved survival (69 vs. 48 d; P = 0.026). CONCLUSIONS: Use of intrapleural urokinase does not reduce dyspnea or improve pleurodesis success compared with placebo and cannot be recommended as an adjunct to pleurodesis. Other palliative treatments should be used. Improvements in hospital stay, radiographic appearance, and survival associated with urokinase require further evaluation. Clinical trial registered with ISRCTN (12852177) and EudraCT (2008-000586-26).

Cost-effectiveness of indwelling pleural catheter compared with talc in malignant pleural effusion.

BACKGROUND AND OBJECTIVE: Malignant pleural effusion is associated with morbidity and mortality. A randomized controlled trial previously compared clinical outcomes and resource use with indwelling pleural catheter (IPC) and talc pleurodesis in this population. Using unpublished quality of life data, we estimate the cost-effectiveness of IPC compared with talc pleurodesis. METHODS: Healthcare utilization and costs were captured during the trial. Utility weights produced by the EuroQol Group five-dimensional three-level questionnaire and survival were used to determine quality-adjusted life-years (QALYs) gained. The incremental cost-effectiveness ratio (ICER) was calculated over the 1-year trial period. Sensitivity analysis used patient survival data and modelled additional nursing time required per week for catheter drainage. RESULTS: Utility scores, cost and QALYs gained did not differ significantly between groups. The ICER for IPC compared with talc was favorable at $US10 870 per QALY gained. IPC was less costly with a probability exceeding 95% of being cost-effective when survival was <14 weeks, and was more costly when 2-h nursing time per week was assumed for catheter drainage. CONCLUSION: IPC is cost-effective when compared with talc, although substantial uncertainty exists around this estimate. IPC appears most cost-effective in patients with limited survival. If significant nursing time is required for catheter drainage, IPC becomes less likely to be cost-effective. Either therapy may be considered as a first-line option in treating malignant pleural effusion in patients without history of prior pleurodesis, with consideration for patient survival, support and preferences.

Patient-Reported Outcomes in Pleural Effusions: A Systematic Review.

Pleural effusions cause breathlessness, decreased activity levels, and impaired quality of life. Clinical trials of drainage of pleural effusion use patient-reported outcome measures (PROMs) to assess these variables. This systematic review aimed to identify which PROMs have been used in clinical trials in pleural effusions, what variables were assessed, whether they were responsive to pleural interventions, and whether they have been validated in patients with pleural effusions, including a defined minimal clinically important difference (MCID). A systematic review was performed to identify relevant clinical trials from Medline, EMBASE, Emcare, and CINAHL and data were extracted. From 329 abstracts, 29 clinical trials of pleural effusion drainage that used PROMs as an outcome measure were identified. A total of 16 different PROMs were used. The most used PROMs were unidimensional measurements of breathlessness, particularly the visual analogue scale for dyspnoea (VASD), all of which nearly showed improvements in breathlessness following pleural fluid drainage. Other variables commonly assessed included activity levels and health-related quality of life. Multidimensional PROMs showed inconsistent responsiveness to pleural fluid drainage. Only the VASD was validated in this patient group with a defined MCID. A range of PROMs are used in clinical trials of pleural fluid drainage. No single PROM measures all the outcomes of interest. Unidimensional measurements of breathlessness are responsive to pleural fluid drainage. Only the VASD is validated with an MCID. There is a need for properly validated, response PROMs which measure the key outcomes of interest in this patient group.

Indwelling pleural catheter infection and colonisation: a clinical practice review.

Indwelling pleural catheters (IPCs) are used in the management of malignant pleural effusions, but they can become infected in 5.7% of cases. This review aims to provide a summary of the development of IPC infections and their microbiology, diagnosis and management. IPC infections can be deep, involving the pleural space, or superficial. The former are of greater clinical concern. Deep infection is associated with biofilm formation on the IPC surface and require longer courses of antibiotic treatment. Mortality from infections is low and it is common for patients to undergo pleurodesis following a deep infection. The diagnosis of pleural infections is based upon positive IPC pleural fluid cultures, changes in pleural fluid appearance and biochemistry, and signs or symptoms suggestive of infection. IPCs can also become colonised, where bacteria are grown from pleural fluid drained via an IPC but without evidence of infection. It is important to distinguish between infection and colonisation clinically, and though infections require antibiotic treatment, colonisation does not. It is unclear what proportion of IPCs become colonised. The most common causes of IPC infection and colonisation are Staphylococcus aureus and Coagulase-negative Staphylococci respectively. The management of deep IPC infections requires prolonged antibiotic therapy and the drainage of infected fluid, usually via the IPC. Intrapleural enzyme therapy (DNase and fibrinolytics) can be used to aid drainage. IPCs rarely need to be removed and patients can generally be managed as outpatients. Work is ongoing to study the incidence and significance of IPC colonisation. Other topics of interest include topical mupirocin to prevent IPC infections, and whether IPCs can be designed to limit infection risk.

The Psychosocial Impact of Indwelling Pleural Catheters: A Scoping Review.

We aimed to identify research on the psychosocial impact of Indwelling Pleural Catheters (IPC); report on the extent, range, and nature of studies; and summarize the findings. A secondary aim was to capture reports on patient support needs and/or self-management of IPC. A systematic literature search was undertaken, with evidence synthesis planned if sufficient literature was identified. We searched ten databases available through the United Kingdom National Health Service Knowledge and Library Hub: the British Nursing Index (BNI), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane, Excerpta Medica Database (Embase), Exerpta Medica Care (Emcare), E-thesis Online Service (EThOS), Medical Literature Analysis and Retrieval System Online (Medline), National Grey Literature Collection, Psychological Information Database (PsycInfo), and PubMed. We included studies reporting on the psychosocial impact of indwelling pleural catheters or their effect on quality of life (QoL). The latter was limited to those studies using qualitative research methods from which we could identify psychosocial impacts. The evaluation of psychosocial factors was not the primary objective of any identified study, and we found no studies in which quality of life was assessed using qualitative methods. Two studies met the inclusion criteria but only tangentially. While indwelling pleural catheters may improve the quality of life in patients with pulmonary effusion when assessed quantitatively, there is a dearth of research examining their psychosocial impact.

Therapeutic thoracentesis symptoms and activity: a qualitative study.

INTRODUCTION: Malignant pleural effusions (MPEs) commonly occur in patients with advanced cancer. Drainage of fluid is used to relieve symptoms and improve quality of life. OBJECTIVE: To improve our understanding of how therapeutic aspiration affects symptoms and activities in patients with MPE. METHODS: Patients presenting to the Pleural Clinic at Norfolk and Norwich University Hospital with a confirmed or suspected MPE participated in up to three semistructured interviews during their diagnostic/therapeutic pathway. Interviews were analysed using framework analysis by two researchers independently. RESULTS: Sixteen patients participated. Symptoms reported before drainage included breathlessness, cough, chest pain, fatigue and anorexia. Symptoms affected their activities, including walking, bending over and socialisation. Patients described anxiety about the underlying diagnosis and fear of over-reliance on others. Expectations of drainage outcome varied, with some hoping for a cure and others hoping for any improvement. After drainage, breathlessness, chest pain and cough improved in some patients. They reported feeling and sleeping better, but fatigue and poor appetite remained. Participants were more active after aspiration, but the duration of improvement was a few days only. Despite this, patients still felt the procedure worthwhile. CONCLUSION: Overall health and respiratory symptoms improved following drainage, but constitutional symptoms did not improve. This may be because constitutional symptoms are caused by the underlying cancer. This study suggests that clinicians should consider a range of symptoms, rather than just breathlessness, in planning outcomes for clinical trials. These results are important to inform patients about the potential benefits and duration of symptom improvement after therapeutic aspiration.

Breathlessness Predicts Mortality in Adults: A Systematic Review and Meta-Analysis.

Breathlessness is a commonly encountered symptom, and although its relationship with mortality is well established for many conditions, less clear is this relationship in healthy adults. This systematic review and meta-analysis examines whether breathlessness is associated with mortality in a general population. This is important in understanding the impact of this common symptom on a patient's prognosis. This review was registered with PROSPERO (CRD42023394104). Medline, EMBASE, CINAHL and EMCARE were searched for the terms 'breathlessness' and 'survival' or 'mortality' on January 24, 2023. Longitudinal studies of >1,000 healthy adults comparing mortality between breathless and non-breathless controls were eligible for inclusion. If an estimate of effect size was provided, studies were included in the meta-analysis. Eligible studies underwent critical appraisal, data extraction and risk of bias assessment. A pooled effect size was estimated for the relationship between the presence of breathlessness and mortality and levels of severity of breathlessness and mortality. Of 1,993 studies identified, 21 were eligible for inclusion in the systematic review and 19 for the meta-analysis. Studies were of good quality with a low risk of bias, and the majority controlled for important confounders. Most studies identified a significant relationship between the presence of breathlessness and increased mortality. A pooled effect size was estimated, with the presence of breathlessness increasing the risk of mortality by 43% (risk ratio (RR): 1.43, 95% confidence interval (CI): 1.28-1.61). As breathlessness severity increased from mild to severe, mortality increased by 30% (RR: 1.30, 95% CI: 1.21-1.38) and 103%, respectively (RR: 2.03, 95% CI: 1.75-2.35). The same trend was seen when breathlessness was measured using the modified Medical Research Council (mMRC) Dyspnoea Scale: mMRC grade 1 conferred a 26% increased mortality risk (RR: 1.26, 95% CI: 1.16-1.37) compared with 155% for grade 4 (RR: 2.55, 95% CI: 1.86-3.50). We conclude that mortality is associated with the presence of breathlessness and its severity. The mechanism underlying this is unclear and may reflect the ubiquity of breathlessness as a symptom of many diseases.

Trial Protocol: Reaccumulation rate of pleural effusions after therapeutic aspiration: An observational cohort study to determine baseline factors associated with rate of pleural fluid reaccumulation following therapeutic aspiration in patients with malignant pleural effusion attending a pleural clinic (REPEAT).

Background: Malignant pleural effusion (MPE) is the build-up of pleural fluid in the space between the lung and chest wall due to advanced cancer. It is treated initially by large volume drainage (therapeutic aspiration). If the fluid reaccumulates, a definitive procedure is performed. There is wide variation in rate of reaccumulation. Patients with rapid reaccumulation often attend hospital as an emergency. Conversely, patients with slow reaccumulation do not need a definitive procedure and may experience cancelled or unnecessary procedures. This study aims to create and validate a multivariable prediction model to predict how quickly pleural fluid will reaccumulate in patients with MPE following therapeutic aspiration. Research question: Can we predict how quickly pleural fluid will reaccumulate in patients with MPEs? Methods: A total of 200 patients with known or suspected MPE attending for therapeutic aspiration will be recruited from 5-10 UK hospitals over 20 months. Patients will be enrolled prior to undergoing aspiration. Following this, they will undergo chest X-ray, which will be repeated one week later (treatment as usual). Rate of reaccumulation will be calculated based on change of size of the effusion seen on X-ray. Data will be collected on common clinical biomarkers e.g., size of effusion on pre-aspiration chest X-ray, volume of fluid drained. This data will be analysed to create a clinical score.A further validation cohort of 40 patients will be enrolled in parallel with creation of the score. Anticipated impact: The ability to predict rate of reaccumulation of MPE will enable patients and clinicians to make better informed treatment decisions. For patients with predicted rapid reaccumulation, a definitive procedure could be offered as first-line treatment, rather than a therapeutic aspiration. This will prevent emergency hospital admissions and decrease number of procedures. By contrast, patients whose effusions will recur slowly may avoid an unnecessary procedure.

People with incurable cancer commonly feel breathless due to buildup of fluid around the lung. We treat this by draining fluid off, but it often comes back. When this happens, we offer the patient a permanent implanted drain, so they can drain the fluid off at home. However, sometimes the fluid builds up very quickly. The patient becomes very breathless and needs an emergency hospital admission. In other people, the fluid builds up slowly and they may never need another drain. The aim of this study is to improve treatment by finding a way to predict how quickly fluid will come back. It will be run in five hospitals across England and involve 240 patients over three years. When patients first come to have fluid drained, we will record information about them and their disease. We will measure how quickly the fluid comes back and record hospital admissions and need for fluid drainage over the following three months. We will use this information to create a clinical score. We will then test this score in a second group of patients to make sure it works. The idea for this study came from one of our patients who had just had fluid drained and asked, 'when will it come back?' We couldn't answer his question and therefore developed this study. Our patients and the public have been involved in the design of this study and will continue to be involved. This score will be used to inform patients so they can choose the best treatment for them. If we know the fluid will build up quickly, we can offer patients a permanent drain straight away. If patients know their fluid will build up slowly, they may choose to have the fluid drained when needed without a permanent drain.

Effect of an indwelling pleural catheter vs chest tube and talc pleurodesis for relieving dyspnea in patients with malignant pleural effusion: the TIME2 randomized controlled trial.

CONTEXT: Malignant pleural effusion causes disabling dyspnea in patients with a short life expectancy. Palliation is achieved by fluid drainage, but the most effective first-line method has not been determined. OBJECTIVE: To determine whether indwelling pleural catheters (IPCs) are more effective than chest tube and talc slurry pleurodesis (talc) at relieving dyspnea. DESIGN: Unblinded randomized controlled trial (Second Therapeutic Intervention in Malignant Effusion Trial [TIME2]) comparing IPC and talc (1:1) for which 106 patients with malignant pleural effusion who had not previously undergone pleurodesis were recruited from 143 patients who were treated at 7 UK hospitals. Patients were screened from April 2007-February 2011 and were followed up for a year. INTERVENTION: Indwelling pleural catheters were inserted on an outpatient basis, followed by initial large volume drainage, education, and subsequent home drainage. The talc group were admitted for chest tube insertion and talc for slurry pleurodesis. MAIN OUTCOME MEASURE: Patients completed daily 100-mm line visual analog scale (VAS) of dyspnea over 42 days after undergoing the intervention (0 mm represents no dyspnea and 100 mm represents maximum dyspnea; 10 mm represents minimum clinically significant difference). Mean difference was analyzed using a mixed-effects linear regression model adjusted for minimization variables. RESULTS: Dyspnea improved in both groups, with no significant difference in the first 42 days with a mean VAS dyspnea score of 24.7 in the IPC group (95% CI, 19.3-30.1 mm) and 24.4 mm (95% CI, 19.4-29.4 mm) in the talc group, with a difference of 0.16 mm (95% CI, −6.82 to 7.15; P = .96). There was a statistically significant improvement in dyspnea in the IPC group at 6 months, with a mean difference in VAS score between the IPC group and the talc group of −14.0 mm (95% CI, −25.2 to −2.8 mm; P = .01). Length of initial hospitalization was significantly shorter in the IPC group with a median of 0 days (interquartile range [IQR], 0-1 day) and 4 days (IQR, 2-6 days) for the talc group, with a difference of −3.5 days (95% CI, −4.8 to −1.5 days; P < .001). There was no significant difference in quality of life. Twelve patients (22%) in the talc group required further pleural procedures compared with 3 (6%) in the IPC group (odds ratio [OR], 0.21; 95% CI, 0.04-0.86; P = .03). Twenty-one of the 52 patients in the catheter group experienced adverse events vs 7 of 54 in the talc group (OR, 4.70; 95% CI, 1.75-12.60; P = .002). CONCLUSION: Among patients with malignant pleural effusion and no previous pleurodesis, there was no significant difference between IPCs and talc pleurodesis at relieving patient-reported dyspnea. TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN87514420.

Breathlessness Predicts Survival in Patients With Malignant Pleural Effusions: Meta-analysis of Individual Patient Data From Five Randomized Controlled Trials.

BACKGROUND: Patients with malignant pleural effusions (MPEs) experience breathlessness and poor survival. Breathlessness is associated with poor survival in other conditions. RESEARCH QUESTION: Is breathlessness, measured using a visual analog scale for dyspnea (VASD), associated with survival in patients with MPE? STUDY DESIGN AND METHODS: Individual patient data from five randomized controlled trials of 553 patients undergoing interventions for MPE were analyzed. VASD was recorded at baseline and daily after intervention. Patients were followed up until death or end of trial. Univariate and multivariable Cox regression were used to identify factors associated with survival. RESULTS: Baseline VASD was significantly associated with worse survival, with a hazard ratio of 1.10 (95% CI, 1.06-1.15) for a 10-mm increase in VASD. On multivariable regression, it remained a significant predictor of survival. Mean 7-day VASD and mean total VASD were also predictors of survival (mean 7-day VASD: hazard ratio [HR], 1.26 [95% CI, 1.19-1.34]; total VASD: HR, 1.25 [95% CI, 1.15-1.37]). Other predictors of survival were serum C-reactive protein level and tumor type. Previous treatment with chemotherapy, performance status, pleural fluid lactate dehydrogenase, serum albumin, hemoglobin, serum neutrophil:lymphocyte ratio, and size of effusion were associated with survival on univariate but not multivariable analysis. INTERPRETATION: Breathlessness, measured using VASD at baseline and postprocedure, is a predictor of survival in patients with MPE.

Diagnostic accuracy, safety and utilisation of respiratory physician-delivered thoracic ultrasound.

BACKGROUND Thoracic ultrasound-guided pleural procedures are associated with fewer adverse events than 'blind' procedures for patients with pleural effusion. Ultrasound is increasingly practised by respiratory physicians but there has been no prospective assessment of its safety and diagnostic accuracy when delivered by respiratory physicians. METHODS The activity level, safety and diagnostic accuracy of thoracic ultrasound delivered by respiratory physicians were prospectively assessed. Diagnostic accuracy was assessed using a stepwise pragmatic approach (recording if pleural fluid was obtained or effusion was present on another radiological modality). In the absence of the above, ultrasound clips were reviewed by a blinded radiologist. The number of ultrasounds referred to radiologists and adverse events within 1 week were recorded. The complication rate was compared with the published literature. RESULTS 960 ultrasound scans occurred over a 3 year period. The activity of the service increased over time, as a result of increased use of interventional ultrasound. The referral rate to radiology remained constant over the study period (mean proportion 4.0%). Physician-delivered ultrasound correctly identified the presence/absence of pleural fluid in 951 of 955 evaluable scans (99.6% CI 98.9% to 99.9%). The major complication rate was 3/558=0.5% (95% CI 0.1% to 1.6%), which compared favourably with the identified published literature. CONCLUSION Respiratory physician-delivered thoracic ultrasound appears to be safe and effective in the diagnosis/intervention of pleural effusion, and is associated with a major complication rate comparable with that of published studies. Continued liaison with the radiology service has here been demonstrated as a requirement for a physician-based service.

Factors influencing the measurement of pleural fluid pH.

PURPOSE OF REVIEW: Pleural fluid pH measurement is important in the management of patients with exudative pleural effusions, especially in guiding treatment of parapneumonic effusions. Common variations in the method used to sample pleural fluid affect the accuracy of the value obtained. This article reviews the effects of these variations. RECENT FINDINGS: Pleural fluid pH is decreased by exposure to acidic fluids, such as retention of local anesthetic or heparin in the syringe or sampling following infiltration of local anesthetic. Exposure of the sample to air leads to an increase in pH. If immediate analysis is not possible, delay of up to 4 h does not cause a significant change in pH, even when the sample is kept at room temperature. It is essential that a blood gas analyzer is used to obtain accurate pH measurement.These factors have less effect on the glucose concentration, which may be used to guide management if an accurate pH value is not available. SUMMARY: Several common variables in collection method can lead to a clinically significant alteration in the pH value obtained. An evidence-based method for sampling and handling pleural fluid in order to obtain an accurate pH measurement is described.

Clinically important factors influencing the diagnostic measurement of pleural fluid pH and glucose.

RATIONALE: Accurate pleural fluid pH and glucose measurement is a key component in the diagnosis and management of patients with pleural effusion. Standardized methods of pleural fluid collection have not been defined. OBJECTIVES: To assess the effect of common clinical factors that may distort measurement accuracy of pleural fluid pH and glucose. METHODS: Ninety-two exudative pleural aspirates were collected in commercially available blood gas syringes. MEASUREMENTS AND MAIN RESULTS: Samples were analyzed immediately using a blood gas analyzer. The effects of residual air, lidocaine, heparin, and delay in analysis (24 h) on pH and glucose measurement accuracy were assessed. Pleural fluid pH was significantly increased by residual air (mean +/- SD, 0.08 +/- 0.07; 95% confidence interval [CI], 0.06 to 0.09; P < 0.001) and significantly decreased by residual lidocaine (0.2 ml; mean change in pH, -0.15 +/- 0.09; 95% CI, -0.13 to -0.18; P < 0.001) and residual heparin (mean change in pH, -0.02 +/- 0.05; 95% CI, -0.01 to -0.04; P = 0.027). Pleural fluid pH was stable at room temperature for 1 hour and significantly increased at 4 (mean +/- SD, 0.03 +/- 0.07; 95% CI, 0.01 to 0.04; P = 0.003) and 24 hours (0.05 +/- 0.12; 95% CI, 0.03 to 0.08; P < 0.001). Pleural fluid glucose concentration was not clinically significantly altered by residual air, lidocaine (up to 0.4 ml), or 24-hour analysis delay. CONCLUSIONS: Accuracy of measured pleural pH is critically dependent on sample collection method. Residual air, lidocaine, and analysis delay significantly alter pH and may impact on clinical management. Pleural fluid glucose concentration is not significantly influenced by these factors. Protocols defining appropriate sampling and analysis methods are needed.