Thoracentesis: a safe procedure in mechanically ventilated patients

Pleural effusion in critically ill patients and intensive care setting

Pleural effusion usually causes a diagnostic dilemma with a long list of differential diagnoses. Many studies found a high prevalence of pleural effusions in critically ill and mechanically ventilated patients, with a wide range of variable prevalence rates of up to 50%-60% in some studies. This review emphasizes the importance of pleural effusion diagnosis and management in patients admitted to the intensive care unit (ICU). The original disease that caused pleural effusion can be the exact cause of ICU admission. There is an impairment in the pleural fluid turnover and cycling in critically ill and mechanically ventilated patients. There are also many difficulties in diagnosing pleural effusion in the ICU, including clinical, radiological, and even laboratory difficulties. These difficulties are due to unusual presentation, inability to undergo some diagnostic procedures, and heterogenous results of some of the performed tests. Pleural effusion can affect the patient’s outcome and prognosis due to the hemodynamics and lung mechanics changes in these patients, who usually have frequent comorbidities. Similarly, pleural effusion drainage can modify the ICU-admitted patient’s outcome. Finally, pleural effusion analysis can change the original diagnosis in some cases and redirect the management toward a different way.

Pleural Effusions in the Critically Ill and "At-Bleeding-Risk" Population

Thoracentesis is a common bedside procedure, which has a low risk of complications when performed with thoracic ultrasound and by experienced operators. In critically ill or mechanically ventilated patients, or in patients with bleeding risks due to medications or other coagulopathies, the complication rate remains low. Drainage of pleural effusion in the intensive care unit has diagnostic and therapeutic utility, and perceived bleeding risks should be one part of an individualized and comprehensive risk-benefit analysis.

Utility of pleural effusion drainage in the ICU: An updated systematic review and META-analysis

PURPOSE

The effects on the respiratory or hemodynamic function of drainage of pleural effusion on critically ill patients are not completely understood. First outcome was to evaluate the PiO₂/FiO₂ (P/F) ratio before and after pleural drainage.

SECONDARY OUTCOMES

evaluation of A-a gradient, End-Expiratory lung volume (EELV), heart rate (HR), mean arterial pressure (mAP), left ventricular end-diastolic volume (LVEDV), stroke volume (SV), cardiac output (CO), ejection fraction (EF), and E/A waves ratio (E/A). A tertiary outcome: evaluation of pneumothorax and hemothorax complications.

MATERIALS AND METHODS

Searches were performed on MEDLINE, EMBASE, COCHRANE LIBRARY, SCOPUS and WEB OF SCIENCE databases from inception to June 2018 (PROSPERO CRD42018105794).

RESULTS

We included 31 studies (2265 patients). Pleural drainage improved the P/F ratio (SMD: -0.668; CI: -0.947-0.389; p < .001), EELV (SMD: -0.615; CI: -1.102-0.219; p = .013), but not A-a gradient (SMD: 0.218; CI: -0.273-0.710; p = .384). HR, mAP, LVEDV, SV, CO, E/A and EF were not affected. The risks of pneumothorax (proportion: 0.008; CI: 0.002-0.014; p = .138) and hemothorax (proportion: 0.006; CI: 0.001-0.011; p = .962) were negligible.

CONCLUSIONS

Pleural effusion drainage improves oxygenation of critically ill patients. It is a safe procedure. Further studies are needed to assess the hemodynamic effects of pleural drainage.

Safety and Value of Thoracentesis in Medical ICU Patients

The objective of this study was to determine the safety and value of thoracentesis in an ICU, Thoracentesis is a safe procedure for critically ill patients, even those on mechanical ventilators, and usually confirms the suspected diagnosis. However, thoracentesis revealed an unexpected diagnosis that changed management in 12% of patients. Repeat or contralateral thoracentesis is indicated when either the clinical course is inconsistent or may represent a complication of the original diagnosis.

Role of the Interventional Pulmonologist in the Intensive Care Unit

Interventional pulmonology is a new field within the pulmonary and critical care medicine specialty with a focus on invasive diagnostic and therapeutic modalities in airway and pleural disorders. The interventional pulmonologist is highly qualified to take a prominent role in the intensive care unit in a consultative fashion to provide assistance with pleural procedures, establishment and care of artificial airways, and management of patients with respiratory failure attributable to structural central airway disorders. The presence of a dedicated operator with advanced skills facilitates access to specialized procedures in an expeditious and safe manner. Clear communication between the interventional pulmonologist and intensivist is vital to ensure a collaborative effort that delivers optimal patient care.

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.

The diagnosis and management of pleural effusions in the ICU

Pleural effusions are common in critically ill patients. Most effusions in intensive care unit (ICU) patients are of limited clinical significance; however, some are important and require aggressive management. Transudative effusions in the ICU are commonly caused by volume overload, decreased plasma oncotic pressure, and regions of altered pleural pressure attributable to atelectasis and mechanical ventilation. Exudates are sequelae of pulmonary or pleural infection, pulmonary embolism, postsurgical complications, and malignancy. Increases in pleural fluid volume are accommodated principally by chest wall expansion and, to a lesser degree, by lung collapse. Studies in mechanically ventilated patients suggest that pleural fluid drainage can result in improved oxygenation for up to 48 hours, but data on clinical outcomes are limited. Mechanically ventilated patients with pleural effusions should be semirecumbant and treated with higher levels of positive-end expiratory pressure. Rarely, large effusions can cause cardiac tamponade or tension physiology, requiring urgent drainage. Bedside ultrasound is both sensitive and specific for diagnosing pleural effusions in mechanically ventilated patients. Sonographic findings of septation and homogenous echogenicity may suggest an exudative effusion, but definitive diagnosis requires pleural fluid sampling. Thoracentesis should be carried out under ultrasound guidance. Antibiotic regimens for parapneumonic effusions should be based on current pneumonia guidelines, and anaerobic coverage should be included in the case of empyema. Decompression of the pleural space may be necessary to improve respiratory mechanics, as well as to treat complicated effusions. While small-bore catheters inserted under ultrasound guidance may be used for nonseptated effusions, surgical consultation should be sought in cases where this approach fails, or where the effusion appears complex and septated at the outset. Further research is needed to determine the effects of pleural fluid drainage on clinical outcomes in mechanically ventilated patients, to evaluate weaning strategies that include pleural fluid drainage, and to better identify patients in whom pleural effusions are more likely to be infected.

Utility of draining pleural effusions in mechanically ventilated patients

PURPOSE OF REVIEW

Pleural effusions are prevalent in mechanically ventilated patients, and clinicians frequently consider draining the effusions. It is controversial whether patients benefit from pleural drainage in terms of either physiological or clinical outcomes.

RECENT FINDINGS

Pleural drainage may be undertaken for a variety of reasons. Effusions are an important potential source of infection in patients with undifferentiated sepsis. Pleural drainage may improve hypoxemia or lung mechanics, but the physiological response depends on a complex interplay between lung and chest wall compliance, applied positive end-expiratory pressure and drainage volume. Pleural effusions may be associated with significant cyclic lung recruitment and collapse during tidal ventilation. Because effusions are primarily accommodated by descent of the diaphragm, they can also impair diaphragm mechanics significantly. There is very limited data in the literature to support the use of pleural drainage to accelerate liberation from mechanical ventilation, and there are no randomized controlled trials published to date.

SUMMARY

Pleural drainage may benefit certain patient populations based on individual physiological considerations, but randomized controlled trials evaluating the impact on weaning outcomes are lacking. Future research efforts should focus on identifying patient populations most likely to benefit and clarify the mechanisms by which weaning may be accelerated after pleural drainage.

A pseudo-Rumsfeldian approach to pleural effusions in mechanically ventilated patients

Pleural effusions are common in mechanically ventilated patients but what is their significance and how should we manage them? What do we know? What don't we know? What didn't we know we knew? How should we resolve the unknowns?

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.

Toracocentese e biópsia pleural

A toracocentese é o método de escolha para a obtenção de amostras de líquido pleural. Embora seja considerado um procedimento pouco invasivo, é fundamental que a toracocentese obedeça a uma técnica padronizada com a finalidade de aprimorar a chance de diagnóstico e minimizar riscos. A biópsia de pleura tem por objetivo ampliar e complementar a chance de diagnóstico das doenças pleurais, sendo indicada em casos selecionados.

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.

[Diagnosis and management of pleural effusions in critically iII patients]

INTRODUCTION

Pleural effusions are common in ICU patients. Causes include massive fluid resuscitation in shock, pneumonia--either community acquired or nosocomial, cardiac insufficiency, hypoalbuminemia and hepatic impairment. Pleural effusions frequently complicate cardiac and abdominal surgery and haemothorax may complicate trauma.

STATE OF THE ART

The incidence of pleural effusions in the intensive care unit (ICU) varies depending on the screening method used, from about 8% for physical examination to more than 60% for routine ultrasonography. In the absence of clinical parameters to exclude infection pleurocentesis remains an essential aspect of management and is not contraindicated mechanical ventilation. This review of the diagnosis and management of pleural effusions in ICU patients reports the most recent data from the literature. Pleurocentesis can be performed safely in the ICU, even in mechanically ventilated patients. The absence of reliable clinical or laboratory test criteria for determining the cause of pleural effusions and the potentially devastating consequences of failing to diagnose and treat pleural infection are strong reasons to perform pleurocentesis in patients with clinically detectable pleural effusions and no contraindication to the procedure.

PERSPECTIVES

Although the data reviewed indicate that the diagnosis and treatment of pleural effusions should follow the same rules in the ICU as they do elsewhere, several incompletely resolved issues deserve further investigation. These are summarised in an agenda for future research.

Surgeon-performed ultrasound in the ICU setting

Evaluation of critically ill patients is often challenging due to altered sensorium, underlying disease, and the presence of multiple drains or monitoring devices. In such circumstances, the ability of physicians to perform ultrasound examinations in the intensive care unit provides a useful diagnostic and therapeutic adjunct. In this article,we review the application of surgeon-performed ultrasonography in the evaluation and management of critically ill patients.

Creation of an innovative inpatient medical procedure service and a method to evaluate house staff competency

INTRODUCTION

Training residents in medical procedures is an area of growing interest. Studies demonstrate that internal medicine residents are inadequately trained to perform common medical procedures, and program directors report residents do not master these essential skills. The American Board of Internal Medicine requires substantiation of competence in procedure skills for all internal medicine residents; however, for most procedures, standards of competence do not exist.

OBJECTIVE

1) Create a new and standardized approach to teaching, performing, and evaluating inpatient medical procedures; 2) Determine the number of procedures required until trainees develop competence, by assessing both clinical knowledge and psychomotor skills; 3) Improve patient safety.

DESIGN

A Medical Procedure Service (MPS), consisting of select faculty who are experts at common inpatient procedures, was established to supervise residents performing medical procedures. Faculty monitor residents' psychomotor performance, while clinical knowledge is taught through a complementary, comprehensive curriculum. After the completion of each procedure, the trainee and supervising faculty member independently complete online questionnaires.

RESULTS

During this pilot program, 246 procedures were supervised, with a pooled major complication rate of 3.7%. 123 thoracenteses were supervised, with a pneumothorax rate of 3.3%; this compares favorably with a pooled analysis of the literature. 87% of surveyed house staff felt the procedure service helped in their education of medical procedures.

CONCLUSIONS

The "see one, do one, teach one" model of procedure education is dangerously inadequate. Through the development of a Medical Procedure Service, and an associated procedure curriculum and a mechanism of evaluation, we hope to reduce the rate of complications and errors related to medical procedures and to determine at what point competency is achieved for these procedures.

Safety of ultrasound-guided thoracentesis in patients receiving mechanical ventilation

OBJECTIVE

To determine the safety of ultrasound-guided thoracentesis (UST) performed by critical care physicians on patients receiving mechanical ventilation.

DESIGN

Prospective and observational.

SETTING

ICUs in a teaching hospital.

PATIENTS

Two hundred eleven serial patients receiving mechanical ventilation with pleural effusion requiring diagnostic or therapeutic thoracentesis.

INTERVENTIONS

Two hundred thirty-two separate USTs were performed by critical care physicians without radiology support. Anteroposterior chest radiographs were reviewed for possible postprocedure pneumothorax.

RESULTS

Pneumothorax occurred in 3 of 232 USTs (1.3%). The procedure was well tolerated in this critically ill population.

CONCLUSIONS

UST performed in patients receiving mechanical ventilation without radiology support results in an acceptable rate of pneumothorax.

Pleural drainage using central venous catheters

Introduction

The objective of the present study was to evaluate the use of a single lumen 16 G central venous catheter for the drainage of uncomplicated pleural effusions in intensive care unit patients.

Methods

A prospective observational study was performed in two intensive care units of university-affiliated hospitals. The study involved 10 intensive care unit patients with non-loculated large effusions. A 16 G central venous catheter was inserted at the bedside without ultrasound guidance using the Seldinger technique. The catheter was left in situ until radiological resolution of the effusion.

Results

Fifteen sets of data were obtained. The mean and standard deviation of the volumes drained at 1, 6 and 24 hours post catheter insertion were 454 ± 241 ml, 756 ± 403 ml and 1010 ± 469 ml, respectively. The largest volume drained in a single patient was 6030 ml over 11 days. The longest period for which the catheter remained in situ without evidence of infection was 14 days. There were no instances of pneumothorax, hemothorax, re-expansion pulmonary edema and catheter blockage/ disconnections.

Conclusions

The use of an indwelling 16 G central venous catheter is efficacious in draining uncomplicated large pleural effusions. It is well tolerated by patients and is associated with minimal complications. It has the potential to avoid repeated thoracentesis or the use of large-bore chest tubes.

Clinically documented pleural effusions in medical ICU patients: how useful is routine thoracentesis?

STUDY OBJECTIVES

To assess the impact of routine thoracentesis on diagnostic assessment and therapeutic measures in patients with clinically documented pleural effusions.

DESIGN AND SETTING

Prospective, 1-year, three-center study in medical ICU (MICU) patients with physical and radiographic evidence of pleural effusion.

PATIENTS

Of 1,351 patients admitted to three MICUs during the study period, 113 patients had physical and radiographic evidence of pleural effusion, yielding an annual incidence of 8.4%.

INTERVENTION

Routine thoracentesis in 82 patients without contraindications to thoracentesis.

MEASUREMENTS AND RESULTS

Twenty patients (24.4%) had a transudate, 35 patients (42.7%) had an infectious exudate (parapneumonic, n = 21; empyema, n = 14), and 27 patients (32.9%) had a noninfectious exudate. Laboratory parameters including the leukocyte count, the neutrophil percentage in pleural fluid, and the fluid/serum protein and lactate dehydrogenase ratios differed significantly among the three groups. Thoracentesis yielded improvements in the diagnosis and/or treatment in 46 patients (56%): the presumptive (prethoracentesis) diagnosis was changed in 37 patients (32 patients with certain benefit and 5 patients with probable benefit from thoracentesis), of whom 27 patients received a change in treatment based on the new diagnosis; 9 other patients received a change in treatment although the diagnosis remained the same. The only complications were pneumothorax in six patients (7%), all with a favorable outcome after drainage.

CONCLUSION

Infection was the main cause of pleural effusions detected based on physical and radiographic findings in our MICU population. Routine thoracentesis proved a simple and safe means of improving the diagnosis and treatment.

Routine exploratory thoracentesis in ICU patients with pleural effusions: results of a French questionnaire study

PURPOSE

The purpose of this study was to report the opinions of intensivists regarding pleural effusions in patients in the intensive care unit (ICU).

MATERIALS AND METHODS

Questionnaires were sent to 1,032 intensivists, who were members of the French Society of Critical Care.

RESULTS

Four hundred thirty-one questionnaires (41.7%) were returned. Overall, the respondents' estimated the incidence of pleural effusion in ICU patients to be 22.19 +/- 17%, whereas 37 +/- 27% considered that exploratory thoracentesis was likely to determine the cause of the effusion, and 17.36 +/- 16% considered that its results were likely to result in a change in their therapeutic attitude. Sixty-five (15%) physicians, chiefly pulmonologists, performed exploratory thoracentesis routinely (Group 1). Compared with those who did not perform routine thoracentesis (Group 2), they ascribed a higher proportion of pleural effusions to infection (31.3% vs. 13.5%) and were more likely to consider that exploratory thoracentesis had a diagnostic and therapeutic contribution (51.2% vs. 34% and 23% vs. 16%, respectively). In addition to the respiratory medicine subspecialty, the practice of routine exploratory thoracentesis was significantly related to seniority, to the frequency of the suspicion of an infectious cause in the physician's practice, and to his or her appreciation of the risks associated with exploratory thoracentesis. Physicians from Group 1 were also more likely to describe exploratory thoracentesis as a noninvasive procedure.

CONCLUSIONS

The beliefs and attitudes of intensivists regarding pleural effusions and exploratory thoracentesis are divergent. This may be due to the lack of precise guidelines on the topic and prompt the design of further studies to establish precisely the epidemiology and causes of pleural effusions in ICU patients.

Pleural Disease in the Intensive Care Unit

Pleural disease itself is an unusual cause for admission to the intensive care unit (ICU). Pleural complications of diseases and procedures in the ICU are common, however, and the impact on respiratory physiology is additive to that of the underlying cardiopulmonary disease. Pleural effusion and pneumothorax may be overlooked in the critically ill patient due to alterations in radiologic appearance in the supine patient. The development of a pneumothorax in a patient in the ICU represents a potentially life-threatening situation. This article reviews the etiologies, pathophysiology, and management of pleural effusion, pneumothorax, tension pneumothorax, and bronchopleural fistula in the critically ill patient. In addition, we review the potential complications of thoracentesis and chest tube thoracostomy, including re-expansion pulmonary edema.

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.

Pleural effusions in the medical ICU: prevalence, causes, and clinical implications

OBJECTIVE

To determine the prevalence and causes of pleural effusions in patients admitted to a medical ICU (MICU).

DESIGN

Prospective.

SETTING

MICU in a tertiary care hospital.

PATIENTS

One hundred consecutive patients admitted to the MICU at the Medical University of South Carolina whose length of stay exceeded 24 h had chest radiographs reviewed daily and chest sonograms performed within 10 h of their latest chest radiograph.

RESULTS

The prevalence of pleural effusions in 100 consecutive MICU patients was 62%, with 41% of effusions detected at admission. Fifty-seven of 62 (92%) pleural effusions were small. Causes of pleural effusions were as follows: heart failure, 22 of 62 (35%); atelectasis, 14 of 62 (23%); uncomplicated parapneumonic effusions, seven of 62 (11%); hepatic hydrothorax, five of 62 (8%); hypoalbuminemia, five of 62 (8%); malignancy, two of 62 (3%); and unknown, three of 62 (5%). Pancreatitis, extravascular catheter migration, uremic pleurisy, and empyema caused an effusion in one instance each. Heart failure was the most frequent cause of bilateral effusions (13/34 [38%]). When compared with patients who never had effusions during their MICU stay, patients with pleural effusions were older (54+/-2 years, mean+/-SEM, vs 47+/-2 years [p=0.04]), had lower serum albumin concentration (2.4+/-0.1 vs 3.0+/-0.01 g/dL [p=0.002]), higher acute physiology and chronic health evaluation II scores during the initial 24 h of MICU stay (17.2+/-1.1 vs 12+/-1.2 [p=0.010]), longer MICU stays (9.8+/-1.0 vs 4.6+/-0.7 days [p=0.0002]), and longer mechanical ventilation (7.0+/-1.3 vs 1.9+/-0.7 days [p=0.004]). No patient died as a direct result of his or her pleural effusion. Chest radiograph readings had good correlation with chest sonograms (p<0.0001).

CONCLUSION

Pleural effusions in MICU patients are common, and most are detected by careful review of chest radiographs taken with the patient in erect or semierect position. When clinical suspicion for infection is low, observation of these effusions is warranted initially, because most are caused by noninfectious processes that should improve with treatment of the underlying disease.

Safety of thoracentesis in mechanically ventilated patients

As practicing intensivists, we frequently diagnose pleural effusions in mechanically ventilated patients and routinely perform thoracentesis even when the patient is on positive end-expiratory pressure (PEEP). In light of a recent report, we have reviewed our experience. It is of interest that all thoracenteses were performed with patients in the lateral decubitus position.