Thoracentesis and Pleural Effusions

Transcription

1 Thoracentesis and Pleural Effusions Fletcher T. Penney, MD, FHM Medical University of South Carolina Department of Medicine June 6, 2013 / Hospital Medicine Curriculum 1 / 44

2 Outline Introduction Indications for Thoracentesis Contraindications for Thoracentesis How to Perform a Thoracentesis How to Analyze Pleural Fluid 2 / 44

3 Learning Objectives To understand which patients should undergo thoracentesis To understand contraindications to thoracentesis To understand potential complications of thoracentesis To understand how to interpret the results of pleural fluid studies 3 / 44

4 Key Messages Dullness to percussion, and the absence of of reduced tactile fremitus are the two most useful physical exam maneuvers to diagnose or exclude pleural effusions. Patients with bilateral pleural effusions, who are afebrile and likely have CHF usually do not need a thoracentesis. Use ultrasound. Patients with a high probability of a transudative effusion only need protein and LDH checked. 4 / 44

6 Does My Patient Have a Pleural Effusion? 6 / 44

7 Does My Patient Have a Pleural Effusion? A systematic review of the accuracy of the physical exam in the diagnosis of pleural effusion by Wong et al. evaluated percussion auscultatory percussion breath sounds chest expansion tactile vocal fremitus vocal resonance crackles pleural friction rub Wong (2009) 7 / 44

8 Does My Patient Have a Pleural Effusion? Dullness to percussion was the most accurate for making the diagnosis (LR+ 8.7) Absence of reduced tactile vocal fremitus made effusion less likely (LR- 0.21) So, in patients with a low pre-test probability, the absence of reduced tactile fremitus may effectively rule out effusion without requiring a radiograph. Of note, when testing for fremitus having your patient say boy or toy is more accurate than ninety-nine. Wong (2009) 8 / 44

9 Who Needs a Thoracentesis? Patients with a pleural effusion that is large enough to tap without a known cause and the effusion is at least 10mm thick by imaging. OR Effusion of known etiology that has re-accumulated in order to remove fluid to improve symptoms. Light (2002) 9 / 44

10 Who Doesn t Need a Thoracentesis? It is likely appropriate to defer thoracentesis in a patient with: Bilateral pleural effusions with a history and exam suggesting CHF without a fever when the effusions resolve within three days. Light (2002) 10 / 44

12 Who Shouldn t Undergo a Thoracentesis? Elevated INR? Thrombocytopenia? Cellulitis overlying the target site? Patients on mechanical ventilation? 12 / 44

13 Elevated INR and Thrombocytopenia In a review of 1076 thoracenteses performed by trained providers, using ultrasound guidance, there was no difference in bleeding complications between patients with INR <= 1.5 (n = 555), INR > 1.5 (n = 267), INR > 2.0 (n = 139), INR > 2.5 (n = 59), or INR > 3.0 (n = 32). Similarly, no difference was noted in patients with platelets <25k when compared to various groups with higher platelet counts (including > 150k). Patel and Joshi (2011) 13 / 44

14 Elevated INR and Thrombocytopenia Consensus guidelines (2009 and 2012) from the Cardiovascular and Interventional Radiological Society of Europe classify thoracentesis as a low risk procedure for bleeding, and they recommend: Check INR in patients on warfarin or with known/suspected liver disease Check aptt in patients on heparin Do not routinely check platelets or hematocrit Do not withhold aspirin/hold clopidogrel for five days (2012 guidelines) Hold LMWH one dose before procedure Malloy et al. (2009) Patel et al. (2012) 14 / 44

15 Elevated INR and Thrombocytopenia However, these guidelines did still recommend transfusing to a platelet count > 50,000 and giving FFP to INR < 2.0. Other authors have suggested this is not necessary. Malloy et al. (2009) Patel et al. (2012) 15 / 44

16 Cellulitis If there is an infection of the skin and/or soft tissue overlying the target site, you should choose a different site. 16 / 44

17 Mechanical Ventilation Traditional teaching was that thoracenteses should not be performed in patients who are on mechanical ventilation. However a study looking at 232 ultrasound guided thoracenteses performed on these patients with chest radiograph follow-up found that only 3 (1.3%) suffered a pneumothorax, and therefore received chest tubes. By comparison, average rates of pneumothorax have been reported from 6 18% without ultrasound and 1 5% with ultrasound, suggesting the procedure is relatively safe in this population. Daniels and Ryu (2011) Mayo et al. (2004) 17 / 44

19 How to Perform a Thoracentesis The MUSC Library provides access to Procedures Consult, which includes information about: Necessary equipment Anatomical landmarks and considerations Video demonstration of procedural technique Procedure checklist 19 / 44

20 How to Perform a Thoracentesis Figure : Procedures Consult web site 20 / 44

21 How to Perform a Thoracentesis Key points: Use ultrasound guidance Do not withdraw more than ml 21 / 44

22 Post-Procedure Complications Important complications: Pneumothorax Bleeding Reexpansion Pulmonary Edema (REPE) Rates of complications correlate with: practitioner inexperience failure to use ultrasonography aspiration of large (> 1 L) fluid volume 22 / 44

23 Pneumothorax Can occur from: Puncture of the visceral pleura with air leak Improper use of the stop-cock allowing influx of air Drastic lowering of the intrapleural pressure Shear trauma of the pleura Daniels and Ryu (2011) 23 / 44

24 Pneumothorax Estimated rates range from 6 18% without ultrasound, and 1 5% with ultrasound Best practices can reduce rates of complication at an institution by: Standardizing the procedures performed Mandatory training Limiting procedure to those who perform it regularly Using real-time ultrasound Daniels and Ryu (2011) 24 / 44

25 Pneumothorax Ultrasonography (90.9% sensitivity, 98.2% specificity) has been found to be better for the detection of pneumothoraces than chest radiography (50.2% sensitivity, 99.4% specificity) according to a meta-analysis. Additionally, the use of ultrasonography during the procedure has been shown to reduce the risk of a pneumothorax. Alrajhi et al. (2012) 25 / 44

26 When to Check a Chest Radiograph? A chest radiograph is not mandatory after thoracentesis, however one should be obtained if air is aspirated into the syringe during the procedure, or there is loss of tactile fremitus over the upper part of the chest on the side of the procedure. Alternatively, ultrasound can be used to diagnose a pneumothorax. 26 / 44

27 Bleeding As discussed previously, the risk of major bleeding from a thoracentesis is low, and the use of ultrasonography during the procedure can help minimize the risk of bleeding complications. 27 / 44

28 Reexpansion Pulmonary Edema (REPE) REPE can occur when a lung is reexpanded after multiple initial insults pneumothorax, pleural effusion, or severe atelectasis. The mortality, pathophysiology, and risk factors of REPE are not clearly understood. In the setting of thoracentesis, it has been associated with removal of more than 1 to 1.5 L of fluid. Sherman (2003) Feller-Kopman (2012) Maldonado and Mullon (2012) 28 / 44

29 Reexpansion Pulmonary Edema (REPE) It has also been suggested that measuring pressure (manometry) during thoracentesis can allow the practitioner to stop removing fluid when the pressure is below 20 cm H2O, though this is somewhat controversial and unproven. 29 / 44

31 Transudate or Exudate? The first step is to differentiate transudate from exudate. If your suspicion for a transudate is high, checking protein and LDH are all that are initially required. A transudative effusion is caused by unbalanced hydrostatic forces (high pressure), effectively pushing the fluid into the pleural space. An exudative effusion is caused by increased capillary permeability or lymphatic obstruction. 31 / 44

32 Light s Criteria Any of the following suggest that the fluid is an exudate: Ratio of pleural-fluid protein to serum protein > 0.5 Ratio of pleural-fluid LDH to serum LDH > 0.6 Pleural-fluid LDH > 2/3 the upper limit of normal for serum Light s Criteria (when combined) are 98% sensitive for an exudate, and 83% specific. If the clinical scenario strongly suggests transudate, but Light s Criteria are positive, one can check the difference between the serum albumin and the pleural albumin (analogous to a SAAG). A gradient of more than 1.2 g/dl suggests that the fluid is actually a transudate. Light (2002) 32 / 44

33 Transudate If the fluid is consistent with a transudate, no further testing is generally necessary (and may in fact be misleading.) The most common etiologies for a transudate include: Congestive heart failure Cirrhosis Nephrotic syndrome Urinothorax Myxedema CSF leak to the pleura Light (2006) 33 / 44

34 Exudate Exudative effusions can be caused by a variety of etiologies, and further testing is usually necessary to distinguish among them. 34 / 44

35 Cell Count and Differential Bloody appearing fluid should prompt a hematocrit: < 1% of peripheral hematocrit nonsignificant 1 20% of peripheral hematocrit cancer, PE, trauma > 50% of peripheral hematocrit hemothorax Light (2002) 35 / 44

36 ph A ph in the pleural-fluid less than 7.20 suggests the need for drainage of the fluid (empyema), usually with a chest tube. It has a been suggested that a ph in this range correlates with a life expectancy of around 30 days. Light (2002) 36 / 44

37 Gram Stain and Culture Cultures show a higher yield if the bottles are inoculated at the bedside. Cultures for TB are rarely positive. High lymphocyte counts should prompt consideration of TB in the differential and an Adenosine deaminase or gamma-interferon may be helpful. ADA < 40 IU/L or gamma-interferon < 140 pg/ml make TB unlikely. Light (2002) Light (2006) 37 / 44

38 Glucose Low glucose ( < 60 mg/dl) suggests a complicated parapneumonic or malignant effusion. Other potential causes include: hemothorax tuberculosis rheumatoid arthritis Churg-Strauss paraonimiasis lupus pleuritis Light (2002) 38 / 44

39 LDH In addition to distinguishing between transudative and exudative effusions, LDH can be useful as a marker of inflammation. Trending pleural fluid LDH levels can be useful for tracking resolution of the underlying process, as the LDH should normalize as the underlying pathology resolves. Light (2002) 39 / 44

40 Other Tests Cytology and flow cytometry may be useful for diagnosing malignancy. Measuring tumor markers in the pleural fluid has not been proven reliable. Amylase pancreatic disease or esophageal rupture Light (2002) 40 / 44

41 Bibliography I Alrajhi, K, Woo, MY, and Vaillancourt, C. Test characteristics of ultrasonography for the detection of pneumothorax: a systematic review and meta-analysis. Chest, 141(3): , March Daniels, CE and Ryu, JH. Improving the safety of thoracentesis. Current opinion in pulmonary medicine, 17(4): , July Feller-Kopman, D. Point: should pleural manometry be performed routinely during thoracentesis? Yes. Chest, 141(4): , April Light, RW. Clinical practice. Pleural effusion. The New England journal of medicine, 346(25): , June / 44

42 Bibliography II Light, RW. The undiagnosed pleural effusion. Clinics in chest medicine, 27(2): , June Maldonado, F and Mullon, JJ. Counterpoint: should pleural manometry be performed routinely during thoracentesis? No. Chest, 141(4):846 8 discussion 848 9, April Malloy, PC, Grassi, CJ, Kundu, S, Gervais, DA, Miller, DL, Osnis, RB, Postoak, DW, Rajan, DK, Sacks, D, Schwartzberg, MS, Zuckerman, DA, and Cardella, JF. Consensus Guidelines for Periprocedural Management of Coagulation Status and Hemostasis Risk in Percutaneous Image-guided Interventions. JVIR, 20(S): S240 S249, July / 44

43 Bibliography III Mayo, PH, Goltz, HR, Tafreshi, M, and Doelken, P. Safety of ultrasound-guided thoracentesis in patients receiving mechanical ventilation. Chest, 125(3): , March Patel, IJ, Davidson, JC, Nikolic, B, Salazar, GM, Schwartzberg, MS, Walker, TG, and Saad, WA. Consensus Guidelines for Periprocedural Management of Coagulation Status and Hemostasis Risk in Percutaneous Image-guided Interventions. JVIR, 23(6): , June Patel, MD and Joshi, SD. Abnormal preprocedural international normalized ratio and platelet counts are not associated with increased bleeding complications after ultrasound-guided thoracentesis. American Journal of Roentgenology, 197(1):W164 8, July / 44

44 Bibliography IV Sherman, SC. Reexpansion pulmonary edema: a case report and review of the current literature. J Emerg Med, 24(1):23 27, January Wong, CL. Does This Patient Have a Pleural Effusion? JAMA : the journal of the American Medical Association, 301(3):309, January / 44