Procedural Ultrasound In Pediatric Patients: Techniques And Tips For Accuracy And Safety

Table of Contents

 

1. Abstract
2. Introduction
3. Ultrasound-Guided Peripheral Venous Access
   1. Case Presentations
   2. Critical Appraisal of the Literature
   3. Introduction
   4. Procedure
      1. Static Technique
      2. Dynamic Technique
         • Out-Of-Plane Approach
         • In-Plane Approach
         • Combination Of The Out-Of-Plane And In-Plane Approaches
   5. Anatomical Considerations When Placing A Peripheral Line
   6. Case Conclusion
4. Ultrasound-Guided Central Venous Access
   1. Case Presentation
   2. Critical Appraisal Of The Literature
   3. Introduction
      1. Anatomic Relationships Of Arteries And Veins
      2. Internal Jugular Vein Placement
      3. Femoral Vein Placement
   4. Procedure
      1. Static Technique
      2. Dynamic Technique
         • Out-Of-Plane Approach
         • In-Plane Approach
         • Wire-In-Needle Modified Seldinger Technique
   5. Additional Considerations When Placing A Central Line
   6. Case Conclusion
5. Ultrasound-Guided Lumbar Puncture
   1. Case Presentation
   2. Critical Appraisal Of The Literature
   3. Introduction
   4. Procedure
   5. Additional Considerations When Performing A Lumbar Puncture
   6. Case Conclusion
6. Ultrasound-Guided Bladder Catheterization
   1. Case Presentation
   2. Critical Appraisal Of The Literature
   3. Introduction
   4. Procedure
   5. Additional Considerations When Performing Bladder Catheterization
   6. Case Conclusion
7. Ultrasound-Guided Foreign Body Removal
   1. Case Presentation
   2. Critical Appraisal Of The Literature
   3. Introduction
   4. Procedure
   5. Additional Considerations When Removing Foreign Bodies
   6. Case Conclusion
8. Ultrasound-Guided Pericardiocentesis
   1. Case Presentation
   2. Critical Appraisal Of The Literature
   3. Introduction
   4. Procedure
   5. Additional Considerations When Performing Pericardiocentesis
   6. Case Conclusion
9. Ultrasound-Guided Paracentesis
   1. Case Presentation
   2. Critical Appraisal Of The Literature
   3. Introduction
   4. Procedure
   5. Additional Considerations When Performing Paracentesis
   6. Case Conclusion
10. Summary
11. Time- And Cost-Effective Strategies
12. Figures
    1. Figure 1. Static Technique To Identify A Peripheral Vein Under Ultrasound Guidance
    2. Figure 2. Identification Of 2 Points Along The Short Axis Of The Vein To Determine The Long Axis
    3. Figure 3. Using The Pythagorean Theorem To Determine The Depth Of Needle Insertion
    4. Figure 4. Long- And Short-Axis Positioning For Dynamic Vein Cannulation
    5. Figure 5. Deflection Of Anterior Vein Wall By Needle To Determine Needle Location
    6. Figure 6. Angiocatheter Placement Confirmed In Long-Axis View
    7. Figure 8. Differentiation Of An Artery From A Vein
    8. Figure 9. Hyperechoic And Fibrillated Appearance Of Nerves On Ultrasound
    9. Figure 10. Variability In The Relationship Between The Internal Jugular Vein And The Common Carotid Artery
    10. Figure 11. Effect Of The Valsalva Maneuver On The Internal Jugular Vein
    11. Figure 12. Using Ultrasound To Assess Guidewire Status
    12. Figure 13. Identification Of The Spinous Process With Ultrasound
    13. Figure 14. Determining The Sagittal Midline With Ultrasound
    14. Figure 15. Determining The Interspinous Space With Ultrasound
    15. Figure 16. Lumbar Puncture Needle Entry Site
    16. Figure 17. Determination Of The Depth Of The Ligamentum Flavum With Ultrasound
    17. Figure 18. Differentiation Of The Spinous Process From Transverse Process Using Ultrasound
    18. Figure 19. Measurement Of Bladder Width, Length, And Height
    19. Figure 20. 50-mL Bag Of Saline Used As An Acoustic Stand-Off Pad
    20. Figure 21. Metallic Foreign Body In A Finger, Visualized By Ultrasound
    21. Figure 22. Wooden Foreign Body In A Finger, Visualized By Ultrasound
    22. Figure 23. Subxiphoid View Of The Heart For Pericardiocentesis
    23. Figure 24. Apical View Of The Heart For Pericardiocentesis
    24. Figure 25. Parasternal Long View Of The Heart For Pericardiocentesis
    25. Figure 26. Pericardial Fluid On Ultrasound
    26. Figure 27. Pericardiocentesis Needle Insertion Using Ultrasound
    27. Figure 28. Loop Of Bowel Floating In Ascites In The Left Lower Quadrant
13. References

Abstract

Point-of-care ultrasound is becoming more prevalent in pediatric emergency departments as a critical adjunct to both diagnosis and procedure guidance. It is cost-effective, safe for unstable patients, and easily repeatable as a patient's clinical status changes. Point-of-care ultrasound does not expose the patient to ionizing radiation and may obviate the need for procedural sedation. Because the use of point-of-care ultrasound in pediatric emergency medicine is relatively new, the body of literature evaluating its utility is small, but growing. Data from adult emergency medicine, radiology, critical care, and anesthesia evaluating the utility of ultrasound guidance must be extrapolated to pediatric emergency medicine. This issue will review the adult literature and the available pediatric literature comparing ultrasound guidance to more traditional approaches. Methods for using ultrasound guidance to perform various procedures, and the pitfalls associated with each procedure, will also be described.

Introduction

Bedside ultrasound, or point-of-care ultrasound (POCUS), is a critical adjunct to both diagnosis and procedure guidance, and its use is becoming more common in pediatric emergency departments (EDs).^1,2 POCUS was first introduced to the ED more than 20 years ago. It is now widely used in adult emergency medicine, with abundant literature supporting its use. In 2001, the Accreditation Council for Graduate Medical Education mandated that emergency medicine residencies train residents in bedside ultrasound. Although less ubiquitous in the pediatric ED, its use and the pediatric emergency medicine literature supporting its use are rapidly increasing. More than 90% of pediatric emergency medicine fellowships now use bedside ultrasound.³ As of 2013, training in POCUS is an American Board of Pediatrics requirement for pediatric emergency medicine fellowship programs.⁴ In addition, consensus educational guidelines and a model curriculum have been published.⁵ The need for training and a curriculum in pediatric emergency medicine ultrasonography has been endorsed not only by the American Board of Pediatrics, but also by the American Academy of Pediatrics, Society of Academic Emergency Medicine, American College of Emergency Physicians, and the World Interactive Network Focused on Critical Ultrasound.⁶

Ultrasound is an ideal imaging modality in children for many reasons. Obtaining optimal ultrasound images in pediatric patients is easier because children are generally thinner and smaller than adults. POCUS is performed at the bedside and can be repeated as needed as a patient’s clinical condition changes. This portability adds a safety factor to POCUS, as potentially unstable patients do not need to go to the radiology suite for a formal radiological study. In addition, unlike computed tomography (CT) and magnetic resonance imaging, bedside ultrasound allows caregivers and staff members from child life to remain with patients throughout the examination, which may obviate the need for sedation. Most importantly, ultrasound does not expose a child to any ionizing radiation.

This issue of Pediatric Emergency Medicine Practice will provide techniques and tips for the use of POCUS to guide various ED procedures including common procedures (ie, peripheral line placement, lumbar puncture, bladder catheterization, and foreign body removal) and procedures that are more rare and resuscitative (ie, central line placement, paracentesis, and pericardiocentesis).

Ultrasound-Guided Peripheral Venous Access

Case Presentation

A 10-month-old girl presents with vomiting and diarrhea for 3 days. She has had 10 to 15 episodes of nonbilious nonbloody emesis and 5 to 10 episodes of nonbloody diarrhea each day. Her mother brings her to the ED because she has had only 1 wet diaper in the past 12 hours. On examination, she is awake but appears tired. She is afebrile and mildly tachycardic. She cries when examined, but has no tears. Her mucous membranes are dry and her capillary refill is 3 seconds. The remainder of her examination is unremarkable and her bedside glucose is 103 mg/dL. You discuss with the mother the need for a peripheral line, IV fluids to rehydrate her daughter, and a blood draw to check electrolytes. The nurses attempt to place an IV line 3 times but are unsuccessful. They report difficulty finding a vein because the girl is dehydrated. What are your options now? Should you try to place the line using a traditional technique? Would placing a line under ultrasound guidance be faster and more likely to succeed? When placing an ultrasound-guided IV line, is it better to use ultrasound to mark a vein's location or to cannulate the vein using ultrasound guidance in real time? Are there certain vein characteristics you should note when choosing a vein to cannulate? Can any peripheral vein be used for ultrasound-guided line placement?

Critical Appraisal Of The Literature

A literature search was performed in PubMed, using the search terms ultrasound, peripheral, cannulation, access, and emergency, limited to human studies. This search yielded 49 articles, 12 of which were found to be relevant.

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study is included in bold type following the references, where available. The most informative references cited in this paper, as determined by the authors, are noted by an asterisk (*) next to the number of the reference.

1. Ramirez-Schrempp D, Dorfman DH, Tien I, et al. Bedside ultrasound in pediatric emergency medicine fellowship programs in the United States: little formal training. Pediatr Emerg Care. 2008;24(10):664-667. (Survey)


2. Marin JR, Zuckerbraun NS, Kahn JM. Use of emergency ultrasound in United States pediatric emergency medicine fellowship programs in 2011. J Ultrasound Med. 2012;31(9):1357- 1363. (Survey)


3. Cohen JS, Teach SJ, Chapman JI. Bedside ultrasound education in pediatric emergency medicine fellowship programs in the United States. Pediatr Emerg Care. 2012;28(9):845-850. (Survey)


4. American Board of Pediatrics. Pediatric Emergency Medicine: Subspecialty In-training, Certification, and Maintenance of Certification Examinations 2011. Available at: www.abp.org/ sites/abp/files/pdf/emer2011.pdf. Accessed April 7, 2016. (Statement)


5. Vieira RL, Hsu D, Nagler J, et al. Pediatric emergency medicine fellow training in ultrasound: consensus educational guidelines. Acad Emerg Med. 2013;20(3):300-306. (Guidelines)


6. * Marin JR, Lewiss RE, American Academy of Pediatrics Committee on Pediatric Emergency Medicine, et al. Point-of-care ultrasonography by pediatric emergency medicine physicians. Pediatrics. 2015;135(4):e1113-e1122. (Guidelines)


7. Keyes LE, Frazee BW, Snoey ER, et al. Ultrasound-guided brachial and basilic vein cannulation in emergency department patients with difficult intravenous access. Ann Emerg Med. 1999;34(6):711- 714. (Prospective descriptive study; 100 patients)


8. * Costantino TG, Parikh AK, Satz WA, et al. Ultrasonography-guided peripheral intravenous access versus traditional approaches in patients with difficult intravenous access. Ann Emerg Med. 2005;46(5):456-461. (Randomized controlled trial; 60 patients)


9. Bauman M, Braude D, Crandall C. Ultrasound-guidance vs. standard technique in difficult vascular access patients by ED technicians. Am J Emerg Med. 2009;27(2):135-140. (Comparative study; 75 patients)


10. Au AK, Rotte MJ, Grzybowski RJ, et al. Decrease in central venous catheter placement due to use of ultrasound guidance for peripheral intravenous catheters. Am J Emerg Med. 2012;30(9):1950-1954. (Prospective descriptive study; 100 patients)


11. Stein J, George B, River G, et al. Ultrasonographically guided peripheral intravenous cannulation in emergency department patients with difficult intravenous access: a randomized trial. Ann Emerg Med. 2009;54(1):33-40. (Randomized controlled trial; 59 patients)


12. Ault MJ, Rosen BT. The magic wand of the ultrasound? Ann Emerg Med. 2010;55(1):130. (Comment)


13. Hyde RJ, Schmier C, Schofer J, et al. Ultrasonographically guided peripheral intravenous cannulation. Ann Emerg Med. 2010;56(3):310-311. (Comment)


14. Mahler SA, Wang H, Lester C, et al. Short- vs long-axis approach to ultrasound-guided peripheral intravenous access: a prospective randomized study. Am J Emerg Med. 2011;29(9):1194-1197. (Randomized controlled trial; 40 patients)


15. Egan G, Healy D, O’Neill H, et al. Ultrasound guidance for difficult peripheral venous access: systematic review and meta-analysis. Emerg Med J. 2013;30(7):521-526. (Systematic review)


16. Liu YT, Alsaawi A, Bjornsson HM. Ultrasound-guided peripheral venous access: a systematic review of randomized-controlled trials. Eur J Emerg Med. 2014;21(1):18-23. (Systematic review)


17. * Doniger SJ, Ishimine P, Fox JC, et al. Randomized controlled trial of ultrasound-guided peripheral intravenous catheter placement versus traditional techniques in difficult-access pediatric patients. Pediatr Emerg Care. 2009;25(3):154-159. (Randomized controlled trial; 50 patients)


18. Bair AE, Rose JS, Vance CW, et al. Ultrasound-assisted peripheral venous access in young children: a randomized controlled trial and pilot feasibility study. West J Emerg Med. 2008;9(4):219-224. (Randomized controlled trial; 44 patients)


19. Schnadower D, Lin S, Perera P, et al. A pilot study of ultrasound analysis before pediatric peripheral vein cannulation attempt. Acad Emerg Med. 2007;14(5):483-485. (Randomized controlled trial; 40 patients)


20. Riera A, Langhan M, Northrup V, et al. Remember the saphenous: ultrasound evaluation and intravenous site selection of peripheral veins in young children. Pediatr Emerg Care. 2011;27(12):1121-1125. (Prospective descriptive study; 60 patients)


21. Joshi M, Wilson G, Engelhardt T. Comparison of landmark technique and ultrasound guidance for localisation of long saphenous vein in infants and children. Emerg Med J. 2010;27(6):443-445. (Prospective descriptive study; 40 patients)


22. Triffterer L, Marhofer P, Willschke H, et al. Ultrasound-guided cannulation of the great saphenous vein at the ankle in infants. Br J Anaesth. 2012;108(2):290-294. (Prospective descriptive study; 90 patients)


23. Panebianco NL, Fredette JM, Szyld D, et al. What you see (sonographically) is what you get: vein and patient characteristics associated with successful ultrasound-guided peripheral intravenous placement in patients with difficult access. Acad Emerg Med. 2009;16(12):1298-1303. (Prospective descriptive study; 169 patients)


24. Schofer JM, Nomura JT, Bauman MJ, et al. The “Ski Lift”: a technique to maximize needle visualization with the long-axis approach for ultrasound-guided vascular access. Acad Emerg Med. 2010;17(7):e83-e84. (Technique description)


25. Rothschild JM. Ultrasound guidance of central vein catheterization. On Making Health Care Safer: A Critical Analysis of Patient Safety Practices. Rockville, MD: AHRQ Publications; 2001:11. (Statement)


26. American College of Emergency Physicians. Emergency ultrasound guidelines. Ann Emerg Med. 2009;53(4):550-570. (Guidelines)


27. American College of Surgeons Committee on Perioperative Care. Revised statement on recommendations for use of real-time ultrasound guidance forplacement of central venous catheters. Bull Am Coll Surg. 2011;96(2):36-37. (Guidelines)


28. American Society of Anesthesiologists Task Force on Central Venous Access, Rupp SM, Apfelbaum JL, et al. Practice guidelines for central venous access: a report by the American Society of Anesthesiologists Task Force on Central Venous Access. Anesthesiology. 2012;116(3):539-573. (Guidelines)


29. Warkentine FH, Clyde Pierce M, Lorenz D, et al. The anatomic relationship of femoral vein to femoral artery in euvolemic pediatric patients by ultrasonography: implications for pediatric femoral central venous access. Acad Emerg Med. 2008;15(5):426- 430. (Prospective descriptive study; 84 patients)


30. Hopkins JW, Warkentine F, Gracely E, et al. The anatomic relationship between the common femoral artery and common femoral vein in frog leg position versus straight leg position in pediatric patients. Acad Emerg Med. 2009;16(7):579-584. (Prospective descriptive study; 80 patients)


31. Mallinson C, Bennett J, Hodgson P, et al. Position of the internal jugular vein in children. A study of the anatomy using ultrasonography. Paediatr Anaesth. 1999;9(2):111-114. (Prospective descriptive study; 25 patients)


32. Maecken T, Marcon C, Bomas S, et al. Relationship of the internal jugular vein to the common carotid artery: implications for ultrasound-guided vascular access. Eur J Anaesthesiol. 2011;28(5):351-355. (Prospective descriptive study; 600 patients)


33. Wang R, Snoey ER, Clements RC, et al. Effect of head rotation on vascular anatomy of the neck: an ultrasound study. J Emerg Med. 2006;31(3):283-286. (Prospective descriptive study; 156 patients)


34. Sigaut S, Skhiri A, Stany I, et al. Ultrasound guided internal jugular vein access in children and infant: a meta-analysis of published studies. Paediatr Anaesth. 2009;19(12):1199-1206. (Systematic review)


35. Leung J, Duffy M, Finckh A. Real-time ultrasonographically-guided internal jugular vein catheterization in the emergency department increases success rates and reduces complications: a randomized, prospective study. Ann Emerg Med. 2006;48(5):540-547. (Randomized controlled trial; 130 patients)


36. Milling TJ Jr, Rose J, Briggs WM, et al. Randomized, controlled clinical trial of point-of-care limited ultrasonography assistance of central venous cannulation: the Third Sonography Outcomes Assessment Program (SOAP-3) Trial. Crit Care Med. 2005;33(8):1764-1769. (Randomized controlled trial; 201 patients)


37. Gallagher RA, Levy J, Vieira RL, et al. Ultrasound assistance for central venous catheter placement in a pediatric emergency department improves placement success rates. Acad Emerg Med. 2014;21(9):981-986. (Retrospective cohort study; 168 patients)


38. * Shime N, Hosokawa K, MacLaren G. Ultrasound imaging reduces failure rates of percutaneous central venous catheterization in children. Pediatr Crit Care Med. 2015;16(8):718-725. (Systematic review)


39. Arai T, Matsuda Y, Koizuka K, et al. Rotation of the head might not be recommended for internal jugular puncture in infants and children. Paediatr Anaesth. 2009;19(9):844-847. (Prospective descriptive study; 62 patients)


40. Wylie MC, Graham DA, Potter-Bynoe G, et al. Risk factors for central line-associated bloodstream infection in pediatric intensive care units. Infect Control Hosp Epidemiol. 2010;31(10):1049-1056. (Case-control study; 203 case patients)


41. Reyes JA, Habash ML, Taylor RP. Femoral central venous catheters are not associated with higher rates of infection in the pediatric critical care population. Am J Infect Control. 2012;40(1):43-47. (Retrospective cohort study; 4512 patients)


42. Aouad MT, Kanazi GE, Abdallah FW, et al. Femoral vein cannulation performed by residents: a comparison between ultrasound-guided and landmark technique in infants and children undergoing cardiac surgery. Anesth Analg. 2010;111(3):724-728. (Randomized controlled trial; 48 patients)


43. Horowitz R, Gossett JG, Bailitz J, et al. The FLUSH study- -flush the line and ultrasound the heart: ultrasonographic confirmation of central femoral venous line placement. Ann Emerg Med. 2014;63(6):678-683. (Technique description)


44. Stone MB, Mallin M, Cook J. Another WIN for point-of-care ultrasound: the wire-in-needle modified Seldinger technique for ultrasound-guided central venous access. Acad Emerg Med. 2013;20(6):E14-E15. (Technique description)


45. Peterson MA, Pisupati D, Heyming TW, et al. Ultrasound for routine lumbar puncture. Acad Emerg Med. 2014;21(2):130-136. (Randomized controlled trial; 100 patients)


46. Shaikh F, Brzezinski J, Alexander S, et al. Ultrasound imaging for lumbar punctures and epidural catheterisations: systematic review and meta-analysis. BMJ. 2013;346:f1720. (Systematic review and meta-analysis)


47. Sahin T, Balaban O, Sahin L, et al. A randomized controlled trial of preinsertion ultrasound guidance for spinal anaesthesia in pregnancy: outcomes among obese and lean parturients: ultrasound for spinal anesthesia in pregnancy. J Anesth. 2014;28(3):413-419. (Randomized controlled trial; 100 patients)


48. Ferre RM, Sweeney TW, Strout TD. Ultrasound identification of landmarks preceding lumbar puncture: a pilot study. Emerg Med J. 2009;26(4):276-277. (Observational study; 39 patients)


49. Nomura JT, Leech SJ, Shenbagamurthi S, et al. A randomized controlled trial of ultrasound-assisted lumbar puncture. J Ultrasound Med. 2007;26(10):1341-1348. (Randomized con¬trolled trial; 48 patients)


50. Balki M, Lee Y, Halpern S, et al. Ultrasound imaging of the lumbar spine in the transverse plane: the correlation between estimated and actual depth to the epidural space in obese parturients. Anesth Analg. 2009;108(6):1876-1881. (Observational study; 46 patients)


51. * Kim S, Adler DK. Ultrasound-assisted lumbar puncture in pediatric emergency medicine. J Emerg Med. 2014;47(1):59-64. (Prospective descriptive study; 19 patients)


52. Lam SH, Lambert MJ. In reply: ultrasound-assisted lumbar puncture in pediatric patients. J Emerg Med. 2015;48(5):611- 612. (Randomized controlled trial; 26 patients)


53. Restrepo CG, Baker MD, Pruitt CM, et al. Ability of pediatric emergency medicine physicians to identify anatomic landmarks with the assistance of ultrasound prior to lumbar puncture in a simulated obese model. Pediatr Emerg Care. 2015;31(1):15-19. (Observational study; 19 patients)


54. Abo A, Chen L, Johnston P, et al. Positioning for lumbar puncture in children evaluated by bedside ultrasound. Pediatrics. 2010;125(5):e1149-e1153. (Prospective descriptive study; 28 patients)


55. Bruccoleri RE, Chen L. Needle-entry angle for lumbar puncture in children as determined by using ultrasonography. Pediatrics. 2011;127(4):e921-e926. (Prospective descriptive study; 36 patients)


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57. Witt M, Baumann BM, McCans K. Bladder ultrasound increases catheterization success in pediatric patients. Acad Emerg Med. 2005;12(4):371-374. (Observational study; 46 patients)


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59. * Chen L, Hsiao AL, Moore CL, et al. Utility of bedside bladder ultrasound before urethral catheterization in young children. Pediatrics. 2005;115(1):108-111. (Prospective observational study; 248 patients)


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69. Schlager D, Sanders AB, Wiggins D, et al. Ultrasound for the detection of foreign bodies. Ann Emerg Med. 1991;20(2):189-191. (Observational study)


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75. * Friedman DI, Forti RJ, Wall SP, et al. The utility of bedside ultrasound and patient perception in detecting soft tissue foreign bodies in children. Pediatr Emerg Care. 2005;21(8):487-492. (Prospective descriptive study; 105 patients)


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77. Nwawka OK, Kabutey NK, Locke CM, et al. Ultrasound-guided needle localization to aid foreign body removal in pediatric patients. J Foot Ankle Surg. 2014;53(1):67-70. (Case series; 2 patients)


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79. Mandavia DP, Hoffner RJ, Mahaney K, et al. Bedside echocardiography by emergency physicians. Ann Emerg Med. 2001;38(4):377-382. (Prospective descriptive study; 515 patients)


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82. Nagdev A, Stone MB. Point-of-care ultrasound evaluation of pericardial effusions: does this patient have cardiac tamponade? Resuscitation. 2011;82(6):671-673. (Case report)


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84. Tsang TS, Enriquez-Sarano M, Freeman WK, et al. Consecutive 1127 therapeutic echocardiographically guided pericardiocenteses: clinical profile, practice patterns, and outcomes spanning 21 years. Mayo Clin Proc. 2002;77(5):429- 436. (Retrospective descriptive study; 977 patients)


85. Tsang TS, El-Najdawi EK, Seward JB, et al. Percutaneous echocardiographically guided pericardiocentesis in pediatric patients: evaluation of safety and efficacy. J Am Soc Echo-cardiogr. 1998;11(11):1072-1077. (Retrospective descriptive study; 73 patients)


86. Molkara D, Tejman-Yarden S, El-Said H, et al. Pericardiocentesis of noncircumferential effusions using nonstandard catheter entry sites guided by echocardiography and fluoroscopy. Congenit Heart Dis. 2011;6(5):461-465. (Retrospective descriptive study; 10 patients)


87. Tsang TS, Freeman WK, Sinak LJ, et al. Echocardiographically guided pericardiocentesis: evolution and state-of-the-art technique. Mayo Clin Proc. 1998;73(7):647-652. (Technique description)


88. Tsang TS, Barnes ME, Hayes SN, et al. Clinical and echocardiographic characteristics of significant pericardial effusions following cardiothoracic surgery and outcomes of echo-guided pericardiocentesis for management: Mayo Clinic experience, 1979-1998. Chest. 1999;116(2):322-331. (Retrospective descriptive study; 245 patients)


89. De Gottardi A, Thevenot T, Spahr L, et al. Risk of complications after abdominal paracentesis in cirrhotic patients: a prospective study. Clin Gastroenterol Hepatol. 2009;7(8):906- 909. (Prospective descriptive study; 171 patients)


90. Grabau CM, Crago SF, Hoff LK, et al. Performance standards for therapeutic abdominal paracentesis. Hepatology. 2004;40(2):484-488. (Prospective descriptive study; 628 patients)


91. Mercaldi CJ, Lanes SF. Ultrasound guidance decreases complications and improves the cost of care among patients undergoing thoracentesis and paracentesis. Chest. 2013;143(2):532-538. (Observational cohort study; 565 patients)


92. Patel PA, Ernst FR, Gunnarsson CL. Evaluation of hospital complications and costs associated with using ultrasound guidance during abdominal paracentesis procedures. J Med Econ. 2012;15(1):1-7. (Retrospective descriptive study; 1297 patients)


93. Nazeer SR, Dewbre H, Miller AH. Ultrasound-assisted paracentesis performed by emergency physicians vs the traditional technique: a prospective, randomized study. Am J Emerg Med. 2005;23(3):363-367. (Randomized controlled trial; 100 patients)


94. Irshad A, Ackerman SJ, Anis M, et al. Can the smallest depth of ascitic fluid on sonograms predict the amount of drainable fluid? J Clin Ultrasound. 2009;37(8):440-444. (Prospective descriptive study; 29 patients)