HOW ULTRASONOGRAPHIC GUIDED THORACENTESIS SCORES OVER BLIND PROCEDURES?

Thoracentesis is tapping of pleural fluid from the pleural cavity for either diagnostic or therapeutic purposes. These are the frequently encountered procedures in the medical practices. Many conditions warrant sending the cases of pleural effusion cases for intervention. Most of the cases had been tried blindly first in their respective departments but failed because of various reasons. It had been documented regarding the advantages and disadvantages of blind and ultrasonography (USG) guided procedures. The aim of the study was to highlight the advantages and benefits of USG guided thoracentesis. We carried out USG guided thoracentesis of fifty cases in our radiology section who were referred to us by various departments. There were 19 female (38%) and 31 male (62%) patients. All these candidates had failed in blind procedures, when tried first. All these cases underwent USG guided thoracentesis with almost negligible complications. These were found to be having pleural fluid collection due to different underlying pathologies. There was no major complication in any of the cases who underwent thoracentesis. We reiterate by this study that USG guided procedures in thoracentesis should be the first choice in the tapping of pleural fluid. This is a quick, affordable, and without any discomfort to the patient.


Introduction
Pleural aspiration (thoracocentesis) and chest needle insertion may be required in many different clinical settings for a variety of indications. This is frequently required and asked for in the daily medical practice. 1 The prevalence of pleural effusion in the intensive care units can vary between 40 % to 60%. There is a need for interventions in these type of cases for either diagnostic or therapeutic purposes. 2 The most common causes of pleural effusion in our population are infectious exudates (43%), non-infectious exudates (33%), and transudates (24%), 3 The most common cause of pleural effusion is due to hemothorax (7%) which is found among those patients who undergo cardiac surgery. Dyspnoea is the most common symptom among these patients. 4 There is an evidence of more danger of complications by attempting the procedures with wide-bore needles.
Small bore needles with the Seldinger technique also are not without any serious complications. 5 The use of blind technique is especially associated with higher complications (18% of cases). 6 So in these settings, USG guided needle aspiration is well versed and handy technique to reduce complications. The aim of this study was to evaluate the success of USG guided thoracocentesis in patients in which blind technique was not successful and to determine the prevalence of complications in these patients following this procedure.

Material and Methods
The study was conducted in the SGT Medical College and Hospital. A prospective study was carried out on 50 patient referred for USG guided throacocentesis to the radiology department of SGT Medical College. In most of the cases the procedure was elective and diagnostic. There was19 female (38%) and 31 males (62%) patients. The age group included 23 years to 65 years (average 41 years). Pleural aspiration was done in the clear area under full aseptic   conditions. All these procedures were done as elective procedures. Patients with normal International Normalized Ratio (INR) were selected. No one was taking any anticoagulants. The patient was made to lie down and volume of fl uid was obtained by using a method developed by Bailik et al. Then the patient is made to sit straight with the back facing the radiologist. Lidocaine 1% is infi ltrated locally prior to the procedure. One takes particular attention to the skin, periostium and the pleura during the procedure. The volume can be calculated by ultrasound if there are many small pockets as all dimensions can be visualized.An 18 bore needle is inserted via skin after local antisepsis. A lumbar puncture needle is used in cases where the depth of pleural effusion is more than 15 mm from the skin. The needle is guided by USG all throughout the procedure, In the intercostal space we go above the lower rib so as to avoid nerve or vessel injury. Then syringe suction is done. After desired fl uid is obtained wound is closed by an aseptic procedure. When the amount of pleural fl uid collection is reasonably more, fl uid can be aspirated without any complications (Fig. 1).

Sharma et al
The problem comes when there is minimal pleural fluid collection. The diagnostic tap is very accurate which can only be targeted with the help of sonographiic examination (Fig. 2). Ultrasound guidance is of utmost importance when the pleural fluid collection is with multiple septations.USG guidance is the gold standard in drainage of these types of loculated fluid collections (Fig. 3). The proper consent of all the patients were take and there were no ethical issue involved.

Results
In all the 50 patients that were taken, throacocentesis was performed successfully for all the cases. In no cases there were any long term complications. Patients felt pain for only few minutes. There was no afterprocedural complication encountered in these cases. The procedure was quite convenient and acceptable as many procedures were carried out in ICU. The tap was diagnostic in nature in the majority of the cases. However, in seven cases, more than 100 ml of fluid was removed and that was even therapeutic as it helped recoil of lung ( Table 1). The details of cytological analysis had shown that 22 (44%) were tubercular in origin. There were 14 (28%) case of transudate in nature (Table2).

DISCUSSION
Pleural fluid is collected in excess due to various factors. The patients are evaluated on the grounds of the symptomatology. Thoracentesis is used for both diagnostic as well as therapeutic purposes. The most common method used to tap the pleural fluid was developed by Bailik et al. [7][8][9][10] The procedure is always carried out with local anaesthesia with 1% lidocaine. The skin is made antiseptic and special attention is given to the periosteum and pleura during the procedures. 11 Pleural effusion can either be exudative or transudate.
Patients are symptomatic with dyspnoea when excessive pleural fluid collections are encountered. The background reason could be because of transudative or exudative. The drainage of this excessive fluid leads to improve the breathing. 12 USG guided procedures are very safe as the blind procrdures lead to many complications like hemothorax, pneumothorax and spreading the infection. 13 The risk of pneumothorax is quite high (18%) in these cases. 6 On the other hand USG guided throacocentesis also encounter problems like failure of puncture with untrained hands. USG remain totally operator dependent for these type of procedures. 14 In our study, a high rate of success was achieved using USG guided throacocentesis. The difficulty was encountered with thin bore needles when thick bore needles were not used. The majority of the procedures were diagnostic in nature. A longer one like lumbar puncture needles under USG guidance were with almost total success. In 21 cases, the pleural effusion on was localized and volume was less; about 40 -50 ml. It was difficult to perform a diagnostic tap in such small volume, however, it was easily tapped under USG guidance.
Pleural fluid in cases of tumors and tuberculosis was thick because of proteinaceous contents. Multiple septations take place in these cases and the exact volume is shown as false 15 as we have shown in our third case (Fig 3). USG helped to guide the needle to largest pocket and take diagnostic fluid .In some cases multiple pockets could be assessed from different location and therapeutic tap was done. In one case the parietal pleura was thick and calcified. USG helped to avoid calcified pleura and guided the needle to reach the fluid avoiding it. Other advantage of USG guided procedure was to know the distance of fluid from the skin so that the exact approach and distance can be calculated.USG helps in negotiating the needle as per the calculations and targeting the site without any complications. This was very helpful in avoiding the lung puncture resulting in to pneumothorax USG guided throacocentesis is a highly efficient, safe and minimally invasive technique. It offers high rate of success and low rate of complications especially for thin bore needle and in diagnostic procedure. It's easy availability and low cost makes it ideal for treatment and diagnosis of pleural effusion both transudative and exudative.