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Ultrasound-guided Pleural Effusion Drainage With a Small Catheter Using the Single-step Trocar or Modified Seldinger Technique

Abusedera, Mohammad MD; Alkady, Ola MD

Journal of Bronchology & Interventional Pulmonology: April 2016 - Volume 23 - Issue 2 - p 138–145
doi: 10.1097/LBR.0000000000000276
Original Investigations

Background: Studies have shown that small-catheter pleural effusion drainage is safe and has a lower complication rate. Our objective was to evaluate the outcomes and the safety of the single-step trocar or the modified Seldinger technique.

Methods: A total of 124 patients (83 men and 41 women), with mean age of 46±18 years and mean duration of drainage 5.3±2 days, were include in the study. The trocar technique was attempted in 201 (86.5%) cases, and the modified Seldinger technique was used in 38 (16.5%) cases.

Results: Technical success was obtained in 96% for the trocar technique and in 100% for the modified Seldinger technique. The procedure time for the trocar and the modified Seldinger techniques was approximately 7 and 12 minutes, respectively (P-value=0.02). The overall success rate was 72.9%. The success rate was highest for massive transudative effusions (98%) followed by malignant effusions (87%), and it was least for parapneumonic effusion/empyema (72 %). Pneumothorax occurred in 10.5% (n=4) for modified Seldinger versus 0.5% (n=1) (P=0.12) for trocar, whereas bleeding occurred in 0% for modified Seldinger and in 1% (n=2) for trocar (P=0.04). The single-step trocar technique was technically unsuccessful in 8 cases (7 had empyema with narrow intercostal spaces and one had kyphoscoliosis); technical success was achieved by using the modified Seldinger.

Conclusion: Ultrasound-guided pleural effusion drainage by catheter insertion is a safe and effective procedure. The success rate is low when the effusion is loculated and septated. Both the trocar and the modified Seldinger techniques can be used. The trocar technique is faster and easier.

*Saad Specialist Hospital, Alkhobar, Eastern Providence, Saudi Arabia

Chest Diseases and Tuberculosis, Sohag University, Egypt

Disclosure: There is no conflict of interest or other disclosures.

Reprints: Mohammad Abusedera, MD, Saad Specialist Hospital, PO 30353, Alkhobar 3192, Eastern Providence, Saudi Arabia (e-mail:

Received September 9, 2015

Accepted March 9, 2016

Chest ultrasound has greatly improved the evaluation and interventional management of many pleural diseases.1 Ultrasound has many advantages, including the absence of ionizing radiation, the sensitivity for detecting small amounts of pleural fluid, and the ability to acquire real-time images. Pleural effusion is commonly encountered clinically, and most patients require thoracocentesis for diagnosis and symptom relief. Pain, cough, shortness of breath, vasovagal reaction, and pneumothorax are potential complications of thoracocentesis.2

The use of the small-bore catheter to drain pleural effusion has recently gained considerable interest. Studies have shown that it is less invasive and better tolerated by patients, with no compromise in efficacy.3

In 1998, Roberts and colleagues reported that the small-bore catheter is highly effective for draining serous and chylous effusion, but it is less effective for empyema and hemothorax. Further, these authors evaluated the utility of the small pigtail catheter for draining pleural effusion and pneumothorax in pediatric patients.4

Gammie et al5 retrospectively reviewed the outcome of 109 cases in which consecutive pigtail catheters were placed at the bedside for pleural effusion drainage without radiographic guidance. Although 24% of those patients had coagulopathy, no complications were encountered. Another study showed that the use of a small indwelling catheter was cost-effective for draining large pleural effusion.6

Ultrasound is a valuable tool in difficult cases such as small pleural effusion or in loculated effusion.7,8

Several studies have shown that ultrasound-guided pleural effusion drainage has a lower complication rate and safer profile than clinically guided thoracocentesis.9,10

Most investigators who used ultrasound-guided thoracocentesis used ultrasound to localize the suitable insertion point rather than perform real-time guidance for needle insertion, and the former technique was not associated with a reduction of pneumothorax.11

Many authors used the modified Seldinger technique guided by ultrasound for catheter insertion,12–14 whereas others used the single-step trocar technique.15

The objectives of this study were to evaluate real-time ultrasound-guided drainage of pleural effusion and to compare the outcomes of the single-step trocar and modified Seldinger techniques.

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This retrospective study was performed by using data from patients who underwent pleural effusion drainage at the university hospital or other tertiary care private practice medical centers from January 2014 to May 2015. The institutional review boards have approved the study. Patient consent was waived because of the retrospective design of the study. Patient consent for the procedure was obtained from all patients or from the patient’s family when the patient could not give the consent.

All patients’ clinical information and pertinent imaging studies were reviewed from medical record before the procedure. The patients’ lab tests were checked, and coagulopathy was corrected before the procedure. The platelet counts were >50,000 and INR was <1.5

Real-time ultrasound-guided pleural effusion drainage was performed at the radiology department or at the patient’s bedside for intensive care unit (ICU) patients for whom transportation might have been difficult and cumbersome.

The real-time ultrasound-guided single-step trocar technique was our standard technique for pleural effusion drainage. The ultrasound exam was performed using a Sonoline Siemens Ultrasound 3 to 5 MHZ convex transducer or a Logiq 8 GE Ultrasound 3 to 5 MHZ transducer. The patient was maintained in semisitting, supine, or lateral oblique position according to the amount of pleural effusion and the presence of loculation. The intercostal approach was carried out in the anterior or middle posterior axillary line or in the posterior infrascapular region according to the accessibility of the pleural effusion or empyema. The insertion site was prepped and was draped in a sterile manner, and the intercostal space, just above the rib, was infiltrated with 4 to 7 mL of 2% lidocaine. The transducer long axis was placed parallel to the intercostal space. A skin nick was performed by using #11 blade followed by dilatation of the skin and subcutaneous tissue with artery forceps. Two brands of multipurpose drainage catheters were used: 8.5, 10.2, or 12 Fr, 25-cm-long multipurpose drainage catheters (William Cook ApS, Bjaeverskov, Denmark) and Neo-Hydro Hydrophilic Drainage 8 or 10 or 12 Fr, 30-cm-long catheters (Bioteque Corporation, Taipei, Taiwan). The catheter was assembled over a metal cannula and inner trocar (Fig. 1). The 3 components were inserted in a single step, with ultrasound guidance, until the catheter tip entered the pleural space (Fig. 2A). Subsequently, the trocar was retracted and the catheter and its metal cannula were advanced to ensure that the entire loop and side-holes were within the pleural cavity; the meta-cannula was then removed and the loop was formed (Fig. 2B) and secured. Pleural effusion samples were obtained through a 3-way stopcock that was connected to a closed circuit collecting bag (a urinary drainage bag with antireflux valve; M Devices Group, Southport, UK), which was secured to the skin by using silk sutures.





We used the modified Seldinger technique when the trocar technique was not successful or when the intercostal space was too narrow to accommodate the single-step trocar. For the modified Seldinger technique, after infiltration anesthesia was applied to the planned tract, an 18- G single-wall vascular access needle (Percutaneous Entry Thinwall Needle 18 G/7 cm; Cook Incorporated, Bloomington, IN; William Cook ApS) was inserted into the pleural space guided by ultrasound. Subsequently, the pleural fluid sample was obtained and a 0.35 straight floppy tip guidewire (Amplatz Stiff Wire Guide 35-90; Cook Incorporated) was inserted through the needle that was visualized by ultrasound. The needle was then removed and a 7-Fr facial dilator was inserted over the guidewire. The facial dilator was removed while keeping the guidewire in place, and the multipurpose drainage catheter with its metal cannula was inserted over the guidewire, into the pleural space. The metal cannula was removed and the catheter was advanced over the guidewire. The guidewire was finally retracted and formation of the loop was confirmed by using ultrasound. The procedure time was estimated from the time of infiltration anesthesia until securing the catheter by silk suture. The catheter was connected to the urinary drainage bag with an antireflux valve (M Devices Group). Both brands of multipurpose pigtail drainage catheters were used for the single-step trocar and modified Seldinger techniques.

A postprocedure chest x-ray (Fig. 3) was obtained for every patient. The catheter output was calculated and the drainage rate was adjusted so that the rate was not more than 1.5 L in the first hour to avoid rapid lung-expansion pulmonary edema.



The catheter was removed when the patient’s symptoms improved and chest ultrasound showed a lack of, or minimal, pleural effusion, or when the catheter output was <1 mL/patient body weight per 24 hours for 3 successive days.

The drainage duration was calculated. Resolution of the pleural effusion was considered clinical success. A persistent large volume of residual pleural effusion, requiring the insertion of a larger tube or surgical intervention, was considered failure. Complications were recorded. The Student t test with a 2-tailed distribution was used to compare the results of the single-step trocar technique and modified Seldinger technique with 2-tail distribution, and a P-value≤0.05 was considered statistically significant.

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The study population consisted of 124 patients for whom 239 pleural effusion drainage procedures were carried out (83 men and 41 women, average age 46±18 y). The following comorbidities were recorded for 99 patients who were in medical or surgical ICU: 82 with end-stage renal disease on regular hemodialysis, 85 with ventilator-dependent respiratory failure, 75 with congestive heart failure, 54 with septicemia, and 23 with advanced malignancy.

Many ICU patients received 2 catheters, and we performed the procedure more than once during the course of the study.

Repeated catheter insertion was necessary for patients with malignant effusion that reaccumulated after complete drainage; sclerotherapy was not attempted in those patients.

The mean drainage duration was 5.3±2 days. The trocar technique was attempted in 201 procedures, and it was technically successful in 193 (96%). The modified Seldinger technique was used in 38 procedures, and it was technically successful in 100%. The procedure time of the trocar and the modified Seldinger techniques were 7 and 12 minutes, respectively. Overall, the pneumothorax rate was 2%, and it was higher for the modified Seldinger than for the trocar technique (10.5%, n=4 vs. 0.5%, n=1). Bleeding occurred in 1% (n=2) for the trocar technique but in 0% for the modified Seldinger technique (Table 1).



The single-step trocar technique was technically unsuccessful in 8 cases (7 with empyema thoracic with narrow intercostal spaces and 1 with kyphoscoliosis), all of which were attempted through the posterior intercostal spaces. Technical success was achieved for all 8 cases when the modified Seldinger was applied.

The anterior intercostal approach was the preferred approach for the trocar technique (90%, n=181), whereas the posterior intercostal approach was used in 10% (n=20). Conversely, the posterior intercostal approach was used in the majority of the modified Seldinger procedure (81%, n=29), whereas the anterior intercostal approach was used in 19% of the procedures (n=7). The difference between the 2 groups was not significant (P=0.4).

Eighty catheters (34.6%) were inserted for malignant effusions in 30 patients (approximately 2.7 catheters per patient); 25 catheters (10.8%) were inserted for parapneumonic effusions/empyema in 25 patients; and 126 catheters (54.5%) were inserted for massive transudative pleural effusions in 69 patients (1.8 catheters per patient). All were inserted for ICU patients with multiple comorbidities who were experiencing respiratory distress that was refractory to medical treatment.

The overall success rate was 72.9%. The success rate was highest when the catheter was used to treat massive transudative effusions (98%), followed by malignant pleural effusions (87%) and parapneumonic effusions/empyemas (72%).

The success rate was the highest for drainage of transudative effusion in both techniques (97% for the trocar technique and 100% for the modified Seldinger technique). The lowest success rate for both techniques was in drainage of parapneumonic effusion/empyema; nevertheless, the success rate was slightly higher in the modified Seldinger technique (75%, n=15) versus the trocar technique (60%, n=3).

The amount of effusion drainage for malignant or parapneumonic or transudative effusion, the duration of catheter use, and the clinical outcome according to which technique was used are shown in (Table 2).



Upgrading from an 8.5 to 12 Fr catheter did not improve clinical success. The catheter size was 8 or 8.5 Fr in 236 procedures, but 10 Fr catheters were used in 3 cases for malignant pleural effusion: 2 were inserted by the trocar technique and 1 was inserted by using the modified Seldinger technique. Upgrading the catheter from 8 to 12 Fr was attempted in 5 patients because of obstruction, and clinical success was obtained in 1 case after upgrading.

Ultrasound revealed loculation and septations in parapneumonic/empyema in which catheter drainage failed.

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Although large-bore (>28 Fr) catheters were recommended traditionally in almost all situations that required chest drainage, this requires a moderately large skin incision, typically using blunt dissection and blind insertion. However, the recent global trend has been the increased use of small-bore chest drains (8 to 16 Fr). Small catheters have several advantages over standard chest tubes—they are easier and less painful to insert, better tolerated once placed, and they have lower insertion-related complication rates.16

The incidences of injury, malposition, and empyema with large-bore versus small-bore tubes are 1.4% versus 0.2%, 6.5% versus 0.6%, and 1.4% versus 0.2%, respectively. One potential disadvantage is a slightly increased incidence of drain blockage with small catheters (8.1%) versus large-bore catheters (5.2%).

The probability of clinical success was reported to be approximately 9 times higher in patients who underwent ultrasound-guided thoracocentesis compared with those who underwent thoracocentesis without ultrasound guidance (odds ratio=8.8).17

Continuous ultrasound guidance reduces the risk of iatrogenic pneumothoraces compared with nonguided thoracocenteses, with reported reductions from 10% to 29% without guidance to 0% to 5% with ultrasound guidance.11,18,19

The mean duration of pleural effusion drainage for different pathologies was reported to be 6.1±2 days.20

In the present study, the mean duration of pleural effusion drainage was longer for transudative effusions (means of 9.2±2.2 and 8.8±1.7 d for the trocar and modified Seldinger techniques, respectively). These results are consistent with other studies showing that the mean duration of pleural fluid drainage by using pigtail catheters ranged from 96 hours to 14 days, with an average of approximately 6 days in many studies.3,5,20–22

With regard to the catheter output amount, the volume was highest in cases with the transudative type (mean of 6400±1600 mL), regardless of the technique. The mean was 6400±1600 mL. This finding is consistent with the results of other investigators who reported that transudative effusions yielded the largest amount of effusion followed by the malignant type, with the lowest amount recorded for the empyema/parapneumonic effusions.12,23

Cavanna et al24 found that the catheter output was higher for ultrasound-guided drainage compared with that when ultrasound guidance was not used.

In the present study, the overall success rate was 72.9%. The success rate was highest when the drain was used to treat massive transudative effusions (98%), followed by malignant pleural effusions (87%) and parapneumonic effusion/empyema (72%). These results are comparable to those of other investigators who found that the success rate was highest when the drain was used to treat posttraumatic hemothorax and postoperative effusion, with a success rate of 61% to 100% and 85%, respectively. Further, the reported success rates were 81.6% to 85.7% for massive transudative effusion, approximately 83.3% for tuberculous effusion, and 75.5% to 81.8% for malignant pleural effusion. The lowest success rates were for parapneumonic effusions/empyema (42% to 72.2%).12,20,24,25

Image-guided drainage of fluid collection is a commonly performed interventional procedure. The modified Seldinger technique with guidewire manipulation and coaxial dilatation and the single-step trocar technique are the 2 main methods of draining fluid collection. Each technique has advantages and disadvantages. The major disadvantages of the trocar technique are the potential for neurovascular injuries and adjacent organ damage.26

Proponents of the trocar method, such as Silverman et al,15 believe that the trocar method is superior to the modified Seldinger technique. According to these investigators, the use of exchange guidewires and dilators in conjunction with the Seldinger technique might allow the introduction of air, thereby increasing the likelihood of pneumothorax. Furthermore, these investigators contend that it is difficult to advance a catheter through the intercostal space and thickened pleura because of buckling of the guidewire or catheter, and such kinking might result in the loss of access or leakage of pleural contents along the dilatation path. Proponents of the Seldinger technique argue that the placement of the chest tube over a guidewire allows more control and decreases the likelihood of complications.27

Abusedera et al28 showed that the technical success of image-guided catheter drainage for abdominal and pelvic fluid collections with the modified Seldinger technique was 100%, whereas it was 87% with the trocar technique.

In the current study, we used both the trocar and the modified Seldinger for catheter insertion. No changes were observed in the drainage duration or in the catheter output according to technique. The drainage output volume was largest for transudative effusion and lowest for empyema/parapneumonic effusion.

Only the procedure time was significantly shorter with the trocar technique than with the modified Seldinger technique. This is presumably because the trocar technique is carried out in a single step once the access point is determined by using ultrasound, whereas multiple steps are required in the Seldinger technique before getting the catheter into the pleural space.

The single-step trocar technique was technically unsuccessful in 8 cases (7 with thoracic empyema with narrow intercostal spaces and 1 with kyphoscoliosis), all of which were attempted through the posterior intercostal spaces. Technical success was achieved for all 8 cases when the modified Seldinger was used. We believe that the Seldinger technique was successful with these cases for the following reasons: we used a small-caliber needle that could pass through the narrow intercostal space and thick pleura, the posterior intercostal space was narrower than the anterior space, and patients cooperated with our request to hold their breath after inspiration to open up the narrow posterior intercostal space. These findings are consistent with a previous study demonstrating unsuccessful catheter insertion by using the trocar technique through thick fibrous capsule of cirrhotic liver to drain liver abscesses.29

The overall clinical success in the present study was approximately 72%; the success rate was the highest for transudative effusion (100% for the modified Seldinger technique and 97% for single-step trocar technique), and it was the lowest for parapneumonic effusion/empyema (75% and 60% for the modified Seldinger and the trocar techniques, respectively), but this difference was not statistically significant.

Upgrading from an 8.5 to 12 Fr catheter was successful in 1 out of 5 cases: all unsuccessful cases had septations and loculations. This result is congruent with that of Chen et al25 who reported significantly higher success rates for draining complex nonseptated effusion compared with the complex septated sonographic pattern (48/60, 80% vs. 41/81, 51%, respectively; P=0.001).

Bleeding was observed in 1% (n=2) of patients when the trocar technique was used and in no patients when the modified Seldinger technique was used, and the difference was significant. This difference can be attributed to the larger needle size of the trocar technique compared with that of modified Seldinger, and therefore the larger needle results in the risk of neurovascular injury during insertion of the catheter/needle complex.

The pneumothorax rate is reported to range from 5 to 10 and 2830,31 but this rate was reduced to approximately 2% in a more recent report in which ultrasound was used.32

In this study, the pneumothorax rate was 2% (n=5): 4 for the modified Seldinger technique and 1 for the trocar technique. These results are comparable to those previous studies that showed a reduced pneumothorax rate when ultrasound was used for both techniques. Pneumothorax was slightly higher for the modified Seldinger (4 cases) technique than for the trocar (1 case) technique, and this may be because guidewire exchange and the insertion of dilators allowed air to enter the pleural space. Air can flow from the atmosphere into the pleural space, as occurs when the negative pressure of the pleural space communicates freely with the atmosphere. This most often occurs as the syringe is removed from a needle that punctures the pleural space.33 Further, the modified Seldinger technique was used for difficult and lengthy procedures, because it was mainly attempted after the trocar failed or in cases that were assumed to be too difficult for the trocar technique.

Serious vascular complications or nerve damage were not observed in this study, and this is consistent with other reports.12,28 Pneumothorax resolved spontaneously without additional interventions.

In conclusion, ultrasound-guided pleural effusion drainage and catheter insertion are safe and effective procedures. The success rate is low when the effusion is loculated and septated. Both the single-step trocar and the modified Seldinger techniques can be used. The trocar technique is faster and easier, but the modified Seldinger is an acceptable option, and this technique can be used when trocar technique fails. Ultimately, the technique with which the operator is most comfortable should be used.

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ultrasound guided; pleural effusion; modified Seldinger; trocar technique; drainage

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