Water Bath Evaluation Technique for Emergency Ultrasound of Painful Superficial Structures MICHAEL BLAIVAS, MD, MATTHEW LYON, MD, LARRY BRANNAM, MD, SANDEEP DUGGAL, MD, AND PAUL SIERZENSKI, MD Researchers have described the use of bedside emergency ultrasound as an effective way to evaluate for and accurately drain potential abscesses. Similarly, descriptions exist of long bone fracture evaluation in the wrist and hands. Tendon injury can also be detected with ultrasound and exploration can be obviated or at least focused. Sonographic examination of painful extremity pathology such as abscesses or lacerations involving the hand or foot can be challenging. Patients may be uncooperative if they experience significant pain when the transducer is placed on the area of interest. While ample amounts of ultrasound gel can decrease the need for firm transducer contact with the skin it is still difficult to obtain a good evaluation without causing any discomfort. The solution may lie in an old technique that has been recently brought back to life for use in hand evaluation in which the patient’s extremity is placed in a water bath. The water bath replaces the need for ultrasound gel or contact between the ultrasound transducer and the patient’s skin, thus eliminating discomfort. We describe 7 cases in which, despite aggressive attempts at pain control, adequate evaluation of extremity pathology was not possible without the use of the water bath technique. Patients reported no discomfort and superior quality images were obtained due to the water bath properties. Emergency sonologists should keep this technique in mind when contact between skin and the ultrasound transducer is likely to cause a patient significant discomfort. (Am J Emerg Med 2004;22:589-593. © 2004 Elsevier Inc. All rights reserved.)
Several recent studies in emergency medicine and some from outside the field have shown the utility of ultrasound for visualization of superficial structures for line placement, abscesses, foreign bodies and effusions.1-5 Work on abscess visualization has shown an increase in accuracy for abscess detection when only cellulitis was suspected.2 Similarly, a needle can be guided directly to the abscess obviating the need for “fishing” which is sometimes required with “blind” sticks that do not use ultrasound or other imaging techniques for needle guidance.6 When visualization of a potential abscess or other superficial structure is sought, ultrasound gel is applied to the skin surface and a linear, high-resolution ultrasound probe is
From the Department of Emergency Medicine, Medical College of Georgia, Augusta GA and the Department of Emergency Medicine, Christiana Care Health System, Newark DE. Manuscript received September 11, 2003; accepted September 11, 2003. Address reprint requests to Michael Blaivas, MD, RDMS, Department of Emergency Medicine, Medical College of Georgia, 1120 15th Street, AF-2039, Augusta, GA 30912-4007. Email:
[email protected] Key Words: Emergency ultrasound, water bath, superficial ultrasound, tendon laceration, soft tissue ultrasound, abscess. © 2004 Elsevier Inc. All rights reserved. 0735-6757/04/2207-0017$30.00/0 doi:10.1016/j.ajem.2004.09.009
used to image the top several centimeters of tissue. This may work well on a large flat or pliable surface such as a thigh but can be much more difficult on a finger or in the web space between two adjacent fingers. In these areas, conforming to irregular body surfaces is difficult and excessive movements of the transducer may cause significant discomfort to the patient. An emergency physician (EP) may be able to use such a large amount of gel that contact with the skin surface is hardly required. However, irregular surfaces are still a problem as the gel can easily move away from the targeted area. The ideal solution could be to immerse the hand entirely in a medium that transmits ultrasound waves. This would mean an extravagant use of ultrasound gel or another means must be sought. Furthermore, typical ultrasound gel is not sterile, an important factor if wound contamination is of concern. Although not typically thought of, water is an excellent medium for ultrasound transmission as evidenced by bladder use as a window to pelvic organs in a transabdominal pelvic ultrasound. We describe 7 cases in which the use of a water bath technique was helpful in providing painless and high quality images of superficial structures in areas difficult to image with standard gel application techniques. CASE 1 RG is a 23-year-old man without significant past medical history who presented to the emergency department (ED) 3 days after suffering a laceration from a broken piece of glass to the palm of his dominant right hand. The patient was unable to flex his right index finger after the injury. Vital signs were within normal limits and the patient was afebrile. On physical examination, an approximately 2 cm linear healing laceration was evident distal to the thenar eminence of the right hand (Fig 1). The site was moderately tender, but there was no erythema or swelling. The patient was incapable of flexing the index finger of the right hand. Extensor function was intact, as well as 2-point discrimination distal to the laceration. An attempt was made to image the area to visualize the flexor tendons using HDI ATL 4000 (Phillips, Bothell, WA). However, adequate visualization was not possible due to the superficial location of the tendons. The patient’s hand was then placed in a clean bedpan filled with sterile water (Fig 2). The linear probe was then placed in the water in close proximity to his palm. The ultrasound revealed a complete flexor tendon disruption (Fig 3). On attempt of flexion of the index finger, the proximal tendon was noted to shorten, while the distal segment of the tendon remained stationary. The wound was 589
590
FIGURE 1.
AMERICAN JOURNAL OF EMERGENCY MEDICINE ■ Volume 22, Number 7 ■ November 2004
A laceration is shown in the patient’s palm.
explored by a consulted plastic surgeon and the diagnosis of complete flexor tendon laceration was confirmed and later repaired.
FIGURE 3. The ultrasound image shows a hematoma (H) where the tendon was lacerated and the proximal end of the flexor tendon (arrow heads) “bunched up”(arrows) where it was cut.
CASE 3 CASE 2 PG is an 18-year-old man without significant past medical history who presented 10 days postrepair of a laceration to the web space between his right 4th and 5th digits. The patient had his sutures removed 3 days before this ED visit, at which time the wound was noted to be healing well. Two days before the ED visit he noted swelling and pain at the scar site without erythema. On physical examination vital signs were within normal limits and the patient was afebrile. The site was exquisitely tender, but there was no erythema over the area of swelling (Fig 4). An attempt was made to image the area to look for abscess using the ILook 25 (SonoSite Bothell,WA.). However, despite good oral analgesia the patient could not tolerate contact with the ultrasound transducer. The patient’s hand was then immersed in a clean bedpan filled with saline and the ultrasound probe, which was suspended in the saline, was held over his hand without touching it. The ultrasound revealed a small abscess measuring 5 mm by 7 mm that was incised and drained after local anesthetic (Fig 5).
FIGURE 2.
The injured hand is seen submerged in a water bath.
CJ is a 54-year-old woman with a history of diabetes and hypertension who presented to the ED with a complaint of right great toe pain and mild swelling. She was afebrile and the rest of the vital signs were unremarkable. Her right first toe appeared mildly swollen in comparison to the contraleral side and there was mild erythema on the tip of the toe. Complaining of severe pain, the patient refused further inspection of her toe. Despite oral narcotic analgesia and considerable discussion, she refused a digital block and further evaluation of the tip of the toe for signs of an abscess. An ILook 25 was brought in to evaluate the distal toe for fluid collections, however the patient again refused to have anything touch her the tip of her toe. Her foot was then placed into a water bath and the tip of the toe was imaged through the water with a linear transducer on the ILook 25. A small complex fluid connection was located. With this visual evidence of an abscess the patient was convinced that a digital block, and incision and drainage were necessary. Approximately 2 cc of puss was drained
FIGURE 4. A healing laceration is seen between the 5th and 4th digits, arrow.
BLAIVAS ET AL ■ WATER BATH ULTRASOUND
591
a single 18-gauge needle to be placed into the fluid collection after sterile preparation of the area. Purulent fluid was drained and the patient was placed on antibiotics after a dose of intramuscular ancef. The patient returned for follow-up in 2 days, at which time no fluid accumulation was noted and the area of erythema was reduced significantly. CASE 6
FIGURE 5. An abscess is showed marked “A”, with fluid (dark area) clearly noted above the skin.
and the patient placed on antibiotics. Follow up showed a slow but complete resolution of the process. No evidence of osteomoylitis was ever found. CASE 4 TK is a 24-year-old man with no significant past medical history who presented to our ED with a complaint of a puncture wound to his left thenar eminence. Earlier that morning, the patient had been holding a piece of wood when it slid out of his hand and he felt a splinter. He removed the splinter, but continued to have pain and now swelling. The patient had no fever and remaining vital signs were normal. Examination of his left palm revealed a small puncture wound in the middle of the thenar eminence. The area was extremely tender to palpation, but no foreign body could be felt. Plain films showed no evidence of a foreign body. The patient’s hand was placed in a water bath and an ultrasound examination was performed. The patient did not complain of any discomfort. Ultrasound revealed a thick anechoic line at an angle in the soft tissue. The foreign body itself could not be seen, however small forceps were guided to the anechoic areas 0.5 cm deep to the skin a piece of wood was retrieved. The patient’s wound was thoroughly irrigated and tetanus updated. He recovered without side effects. CASE 5 IL is a 54-year-old woman with diabetes and hypertension who presented to the ED with a complaint of right foot pain, swelling and redness that began five days prior and had steadily increased. The patient was no longer able to wear shoes and limped when walking. She was afebrile and her vital signs were within normal limits. On physical examination the patient’s right foot showed erythema and swelling over the first metacarpal-phalangeal joint, dorsally. The erythema involved most the distal dorsal foot which was exquisitely tender. The patient balked at further palpation of the affected area. To evaluate if an abscess was present, the patient’s foot was immersed in water, using a clean bedpan. The ILook 25 showed diffuse skin changes from cellulitis and a 1.5 cm x 1.0 cm x 0.7 cm complex fluid collection. The patient refused local anesthesia, but allowed
JP is a 6-year-old boy who presented to the ED with a complaint of right thumb pain and swelling that woke him from sleep at 2 a.m. The patient was afebrile and other vital signs were within normal limits. The patient admitted to thumb sucking, but denied any specific injury. Immunizations were current. On examination there was an obvious paronychia, but no evidence of blistering or pustules. He refused to flex his thumb due to pain. No subungal infection was noted. The pad of the thumb was erythematous, swollen firm, and tender. Capillary refill was within normal limits and sensation was intact. The child and his parents refused a digital block for pain relief. Diagnosis of a felon was considered and a water bath evaluation using a clean basin, and warm water for patient comfort was performed using a linear transducer and the Sonosite 180 PLUS (SonoSite Bothell, WA). The thumb was evaluated in both sagittal and transverse images. A fluid collection representing the paronychia was evident, however the pad of the thumb revealed only edematous tissue consistent with cellulites and drainage of a supposed felon was avoided. The child continued to refuse a digital block and anesthia was obtained using a thumb tourniquet and the perenichia was released within the water bath. The patient was discharged on oral antibiotics with hand surgeon follow-up in 2 days, revealing full resolution of the infection. CASE 7 GG is a 25-year-old man with no significant past medical history who was transferred to our ED with a suspicion of a septic joint. Nine days before arrival the patient had a wooden splinter penetrate the skin over the dorsum of his left third metacarpal-phalangeal joint. The patient pulled out the splinter and did well for 6 days. Approximately 3 days prior, the patient noted redness and swelling over the joint and increasing pain on movement. He was seen at an outside ED where the diagnosis of septic arthritis in the joint was entertained and he was transferred to us. On arrival the patient’s vital signs were within normal limits and he was afebrile. His left third metacarpal-phalangeal joint was exquisitely tender and swollen. There was generalized and poorly demarcated erythema over the joint. The patient had considerable pain to touch and refused to move the finger. His hand was placed in a water bath and a linear array on an Philips HDI 4000 was suspended in the water just above the hand. Long and short axis images were obtained showing a thickened extensor tendon with fluid around the tendon, but not in the joint (Fig 6). Areas of increased blood flow were seen on power Doppler in comparison to the other hand. The consulting hand surgeon elected to forgo the planned joint exploration in the operating room and admitted the patient for intravenous antibiotics. The patient improved on the antibiotic regimen and was discharged home on oral medicines.
592
AMERICAN JOURNAL OF EMERGENCY MEDICINE ■ Volume 22, Number 7 ■ November 2004
FIGURE 6. A long axis cut through the extensor tendon (T) is seen sitting on top of the 2nd metacarpal (M) and proximal phalanx (P). Fluid (F) is seen under the tendon. Note power Doppler signal, arrow heads.
DISCUSSION Evaluation of superficial pathology such as soft tissue infections, foreign bodies and long bone fractures is becoming more common in emergency sonography.7 Benefits can include a more accurate diagnosis of cellulitis or abscess, improved ability for needle directed drainage of fluid collections and improved localization of a foreign body.2,8 Since ultrasound examinations are typically not considered painful, it may not be intuitive that evaluation of an injured or infected extremity may be difficult due to patient discomfort. However, ultrasonographic evaluation of a distal extremity often requires some manipulation, especially if the areas of interest are not immediately on the dorsal or ventral surfaces. Rotation or abduction of fingers or toes can be extremely painful if an infection, tendon laceration, or a fracture is present. In addition, direct contact and subsequent pressure from the transducer may lead to increased pain in certain types of pathology such as infections. As described in the cases presented, a water bath using saline or water, can be used to obviate the need for direct contact between the transducer and the affected body part allowing for several advantages. Better resolution of near surface structures can be obtained, as the ability of most transducers to focus in their extreme “near field” is limited. The lack of direct contact between the transducer and the patient greatly increases patient comfort and cooperation in the exam. In the past, “stand-off” materials such as saline bags or solid gel blocks were used to gain appropriate distance from a near field target and allow better resolution. A water bath obviates the need for this as distance from the surface of the skin can be readily changed. Because pressure from the probe could still be transferred to the patient with these “stand-off” devices, they may still cause discomfort to the patient, whereas this is not the case with a probe suspended in a water bath. In addition, the transducer can be rotated and slanted to obtain different angles of intersection with the
curves of a digit without losing contact between the skin, transducer, and sonographic medium, which often occurs with ultrasound gel. This technique has been described previously by Sierzenski et al, for evaluation of finger tendon injury.9 The researchers compared standard, direct contact ultrasound versus water bath for visualization of a healthy flexor tendon in a model’s hand. The water bath technique was rated superior in ease of use, image quality and ability to evaluate the entirety of the flexor tendon when compared with the traditional direct contract technique. Water bath use increases patient comfort by allowing the emergency physician to avoid using gel in an open wound and thus eliminating the need for direct contact between the probe and the skin. In addition, if for some reason total sterility is desired, the basin as well as the saline or water can all be sterile and the transducer can be placed in a sterile sheath. Tendon anatomy can be difficult to visualize using ultrasound. However, several studies have shown efficacy in using ultrasound to diagnose tendon lacerations.10,11 Tendon lacerations can be searched for under high resolution ultrasound and surgical exploration avoided in some cases. However, it may be difficult to follow the path of the tendon, since the linear probe has difficulty conforming to body curvatures like those of the finger. Maintaining good skin contact is thus difficult and often requires firm consistent pressure, which may cause pain, or risk further injury to the tendon. Even with appropriate technique, the typical scan will often have portions of the image missing due to poor contact of the probe with gel and the skin surface. Tendon evaluation is also complicated by a unique artifact called “anisotropy,” which results in apparent washout of the tendon when the ultrasound beam is not striking the tendon fibers perpendicularly. This is a particularly important concept to bear in mind when evaluating a tendon for injury, such as a laceration or disruption. To compensate for curvatures of the digits and other portion of distal extremities the ultrasound transducer is angled when possible. However, the linear transducer by its nature is does not allow conformation to small body curvatures. However, with the use of a water bath, any angle can be easily achieved by increasing the distance from the transducer to the affected part. Furthermore, due to the high transmissibility of the water medium, very little signal is lost by this increased depth. Therefore, high-resolution images are still possible. Finally, ultrasound evaluation for foreign body has been shown to be very efficacious for diagnosing radio-opaque and radiolucent foreign bodies. In addition it has proven to be superior to standard radiography in localizing the foreign body.12,13 In this context, the water bath and direct contact techniques have been compared for the detection and evaluation of foreign bodies in turkey breast tissue. The researchers found that a water bath afforded the same image detail and quality as the direct contact technique, but resulted in an improvement in image resolution.14 In summary the water bath technique provides a helpful option for evaluation of a painful distal extremity or an area that simply does not allow for easy access using the direct contact technique. Image quality is maintained and often
BLAIVAS ET AL ■ WATER BATH ULTRASOUND
improved and patient comfort and cooperation with examination is increased. As emergency physicians broaden the boundaries of emergency ultrasound away from the traditional and limited scope of practice seen in the early 1990s the water bath will be an excellent alternative technique in their armamentarium. REFERENCES 1. Miller AH, Roth BA, Mills TJ, et al: Ultrasound guidance versus the landmark technique for the placement of central venous catheters in the emergency department. Acad Emerg Med. 2002;9:800-5 2. Hasan N, Tayal VS, Norton NH: Ultrasound Changes Emergency Physician Management of Cellulitis. Acad Emerg Med 2003; 10:426-427 3. Gualtieri E, Deppe SA, Sipperly ME, et al: Subclavian venous catheterization: greater success rate for less experienced operators using ultrasound guidance. Crit Care Med 1995;23:692-7 4. Roy S, Dewitz A, Paul I: Ultrasound-assisted ankle arthrocentesis. Am J Emerg Med 1999;17:300-1 5. Orlinsky M, Knittel P, Feit T, et al: The comparative accuracy of radiolucent foreign body detection using ultrasonography. Am J Emerg Med 2000;18:401-3
593
6. Blaivas M, Theodoro D, Duggal S: Ultrasound-guided drainage of peritonsillar abscess by the emergency physician. Am J Emerg Med 2003;21:155-8 7. Lyon M, Blaivas M: Evaluation of extremity trauma with sonography. J Ultrasound Med 2003;22:625-30 8. Blaivas M: Ultrasound-guided breast abscess aspiration in a difficult case. Acad Emerg Med 2001;8:398-401 9. Sierzenski PR, Leech SJ, Gukhool J, et al: ED Ultrasound Evaluation of the Index Flexor Tendon: A Comparison of Water-bath Evaluation Technique (WET) versus Direct Contact Ultrasound. Acad Emerg Med 2003;10:573 10. Martinoli C, Bianchi S, Derchi LE: Tendon and nerve sonography. Radiol Clin North Am 1999;37:691-711 11. Souissi M, Giwerc M, Ebelin M, et al: Echography of the flexor tendons of the fingers. Presse Med. 1989 4;18:463-6 12. Anderson M, Newmeyer W, Kilgore E: Diagnosing and treatment of retained foreign bodies in the hand. Am J Surg. 1982;144: 63-7 13. Crawford R, Matheson AB: Clinical value of ultrasonography in the detection and removal of radiolucent foreign bodies. Injury 1989;20:341-3 14. Sierzenski PR, Leech SJ, Blaivas M, et al: Water-bath vs. Direct Contact Ultrasound: A Randomized, Controlled, Blinded Image Review. Acad Emerg Med 2003;10:573-574
