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Effect of ultrasonography localization of spinal landmarks on lumbar puncture in the emergency department
RESEARCH FORUM ABSTRACTS
Results: From February to December 2003, 218 patients were consecutively enrolled by 48 physicians. Seventy-nine of the emergency physician–performed ultrasonographs were classified as IUPs and 139 as NDIUPs. Average time to complete the emergency physician–performed ultrasonography was 4 minutes 27 seconds. Of the 79 emergency physician transabdominal ultrasonographs classified as IUPs, radiology, according to their transvaginal ultrasonography, classified 72 as IUPs and 1 as NDIUP, and 6 had no formal radiology ultrasonography but were found to have IUPs on final follow-up. Of the 139 emergency physician–performed ultrasonographs classified as NDIUPs, radiology classified 66 as NDIUP (including 16 read as EUGs) and 66 as IUP, and 8 had no formal radiology ultrasonography (4 were thought to have a high likelihood of EUG and went straight to the operating room after the emergency physician–performed transabdominal ultrasonography). Compared with radiology results, sensitivity of emergency physician–performed ultrasonography for IUP was 53% and specificity was 99%. Free fluid in Morison’s pouch was identified by emergency physician–performed ultrasonography in 12 patients, 9 of whom underwent immediate operative intervention for EUG. The remaining 3 were found to have IUPs with free fluid caused by another source (likely a ruptured cyst). On final follow-up, there were 170 IUPs, 25 EUGs, and 22 patients lost to follow-up. Of the EUGs, 16 underwent immediate operative intervention. The odds ratio for patients with suspected EUG and positive for free fluid in Morison’s pouch for operative intervention compared with that of patients negative for intraperitoneal fluid in Morison’s pouch was 85.3 (95% confidence interval 18.9 to 385.5). Conclusion: Transabdominal emergency physician–performed ultrasonography in suspected EUG is specific for IUP, although sensitivity is only 53%, and therefore can safely exclude EUG in a subset of patients. In addition, identification of free fluid in Morison’s pouch dramatically increases the odds of operative intervention for EUG.
270
Effect of Ultrasonography Localization of Spinal Landmarks on Lumbar Puncture in the Emergency Department
Pisupati D, Heyming TW, Lewis RJ, Peterson MA/Harbor-UCLA Medical Center, Torrance, CA; The David Geffen School of Medicine at UCLA, Los Angeles, CA Study objectives: We determine whether the use of ultrasonographic localization of spinal landmarks performed by emergency physicians affects the performance of lumbar puncture. Methods: This study was performed in an urban county teaching hospital. Adults 18 years or older who were to receive a lumbar puncture for routine clinical care in the emergency department were included. Target patient enrollment was set at 100. Patients were randomized to either undergo preprocedural ultrasonographic localization of the puncture site by the treating emergency physician or to have the puncture site determined by the usual landmark palpation method. Patients were assessed by the treating physician with respect to ease with which puncture-site landmarks could be palpated: easily palpable, difficult to palpate, or unable to palpate. The primary endpoint was success of the procedure as defined by return of cerebrospinal fluid; secondary endpoints were the number of needle passes, pain associated with the procedure, time to perform the procedure, and patient satisfaction with the procedure. The primary analysis compared use of ultrasonography versus palpation alone for all endpoints using the x2 test, Fisher’s exact test, and the Wilcoxon rank sum test, as appropriate. A subgroup analysis was performed by dividing patients into subgroups according to ease of landmark palpation. No consideration was given to terminating this study according to this interim analysis. Results: Sixty-six patients have been enrolled to date. Median age of the patients was 39 years, and 48% were men. Thirty-three (50%) of the patients were considered easy to palpate, 21 (32%) were difficult to palpate, and 12 (18%) were designated as having landmarks that were not palpable. Thirty-three (50%) patients were randomized into each of the 2 study groups. There were no significant differences between the 2 groups in terms of age, sex, body mass index, or ease of palpation of landmarks. For the primary outcome, procedural success, there were no significant differences between those undergoing ultrasonographic localization and those with palpation alone. The only secondary outcome that was significantly different was the median time to perform the procedure, with palpation at 2.8 minutes (interquartile ratio [IQR] 4.8 to 14.2) versus ultrasonography at 7.9 minutes (IQR 0.9 to 14.0; P=.03). Subgroup analysis showed that in the group of patients whose landmarks were either difficult to palpate or not palpable, there was a trend toward improved
OCTOBER 2004
44:4
ANNALS OF EMERGENCY MEDICINE
success rate using ultrasonography. Success rate for ultrasonography group was 100% (14 of 14) versus 84% for the palpation-only group (16 of 19; P=.24). In this subgroup, there were no significant differences between groups for number of needle attempts, pain scores, patient satisfaction, or time of procedure. Conclusion: Preliminary data do not suggest any advantage to the routine use of ultrasonography in patients who require lumbar puncture. There may be an improved success rate in those patients whose spinal landmarks are either difficult to palpate or not palpable. Use of ultrasonography for lumbar puncture localization adds 5.1 minutes to the median time required to perform the procedure.
271
Ultrasonographic Assessment of Bladder Volume Prior to Urinary Catheterization in Infants: Training Operators and Avoiding Unsuccessful Catheterizations
Milling T, Melville L, Santiago L, Van Amerongen R/New York Methodist Hospital, Brooklyn, NY Study objectives: Previous studies have shown a 10% failure rate in urine catheterization in children younger than 2 years. This leads either to an incomplete evaluation or a second procedure, with attendant discomfort for child and parent and increased risk of urethral trauma. We assess a brief educational intervention to teach pediatric and emergency medicine attending physicians and residents to use ultrasonography to measure a bladder index and attempt to define a minimum index predictive of successful catheterization. Methods: Investigators were given a 30-minute training session on identifying and measuring the urinary bladder with ultrasonography on volunteer patients. All sonograms were performed with a Sonosite iLook with 7.5-MgHz vascular probe. Female patients younger than 2 years and male patients younger than 1 year were enrolled prospectively in an urban pediatric emergency department during a 1month period. The physicians performing the catheterization were blinded to the sonographic results. Data recorded were demographics, anterior posterior and lateral bladder diameter, success in obtaining 2 mL of urine (the minimum needed to guarantee urine analysis and culture) and complicating factors. Bladder index was defined as the product of anterior posterior and lateral diameters, expressed in square centimeters. Assuming a perfect sphere, a bladder radius of approximately 0.75 cm would equal a volume of 2 mL. Using this model, the equivalent bladder index would be 2.2 cm2. We expect bladder indices roughly at or above this cutoff to be successful. Results: Twenty patients were enrolled, 11 of whom were girls, average age 7 months, average weight 19 pounds. More than 2 mL of urine were obtained in 16 (80%) patients. These patients had an average AP diameter of 1.9 cm (range 0.7 to 2.8 cm), a lateral diameter of 2.6 cm (range 2.0 to 4.3 cm), and an average bladder index of 4.9 cm2 (range 2.2 to 9.4 cm2). Two failures had anterior posterior diameters of 0.5 and 0 and lateral diameters of 0.5 and 0 (bladder indices of 0.25 and 0). The 2 remaining failures were ascribed to the child urinating during the procedure, and repeated catheterization was not performed. Conclusion: Our results indicate that emergency and pediatric attending physicians and residents can be quickly trained to use ultrasonography to assess infant urinary bladders and calculate a bladder index. Our data suggest that a bladder index of 2.2 cm2 can be used as a cutoff to predict successful catheterization.
272
Can Midlevel Providers Perform Ultrasonography on Superficial Abscesses?
Roppolo LP, Krakover B, Miller AH, Hatten B/University of Texas Southwestern, Dallas, TX Study objectives: Bedside ultrasonography has proven to be a useful adjunct in the diagnoses of abscesses. To date, there are no studies evaluating the utility of ultrasonography in diagnosing superficial abscesses by midlevel providers (physician assistants and nurse practitioners). We determine the ability of midlevel providers to identify superficial abscesses using bedside ultrasonography assessment. Methods: This is an institutional review board–approved, prospective, observational study of adult patients ([18 years) presenting to the emergency department (ED) with a suspected superficial abscess according to physical examination findings of localized swelling, redness, warmth, or fluctuance. The study was conducted in an urban university hospital with a census of more than 130,000 per year during a 6-month period. Bedside ultrasonography was performed
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Results: From February to December 2003, 218 patients were consecutively enrolled by 48 physicians. Seventy-nine of the emergency physician–performed ultrasonographs were classified as IUPs and 139 as NDIUPs. Average time to complete the emergency physician–performed ultrasonography was 4 minutes 27 seconds. Of the 79 emergency physician transabdominal ultrasonographs classified as IUPs, radiology, according to their transvaginal ultrasonography, classified 72 as IUPs and 1 as NDIUP, and 6 had no formal radiology ultrasonography but were found to have IUPs on final follow-up. Of the 139 emergency physician–performed ultrasonographs classified as NDIUPs, radiology classified 66 as NDIUP (including 16 read as EUGs) and 66 as IUP, and 8 had no formal radiology ultrasonography (4 were thought to have a high likelihood of EUG and went straight to the operating room after the emergency physician–performed transabdominal ultrasonography). Compared with radiology results, sensitivity of emergency physician–performed ultrasonography for IUP was 53% and specificity was 99%. Free fluid in Morison’s pouch was identified by emergency physician–performed ultrasonography in 12 patients, 9 of whom underwent immediate operative intervention for EUG. The remaining 3 were found to have IUPs with free fluid caused by another source (likely a ruptured cyst). On final follow-up, there were 170 IUPs, 25 EUGs, and 22 patients lost to follow-up. Of the EUGs, 16 underwent immediate operative intervention. The odds ratio for patients with suspected EUG and positive for free fluid in Morison’s pouch for operative intervention compared with that of patients negative for intraperitoneal fluid in Morison’s pouch was 85.3 (95% confidence interval 18.9 to 385.5). Conclusion: Transabdominal emergency physician–performed ultrasonography in suspected EUG is specific for IUP, although sensitivity is only 53%, and therefore can safely exclude EUG in a subset of patients. In addition, identification of free fluid in Morison’s pouch dramatically increases the odds of operative intervention for EUG.
270
Effect of Ultrasonography Localization of Spinal Landmarks on Lumbar Puncture in the Emergency Department
Pisupati D, Heyming TW, Lewis RJ, Peterson MA/Harbor-UCLA Medical Center, Torrance, CA; The David Geffen School of Medicine at UCLA, Los Angeles, CA Study objectives: We determine whether the use of ultrasonographic localization of spinal landmarks performed by emergency physicians affects the performance of lumbar puncture. Methods: This study was performed in an urban county teaching hospital. Adults 18 years or older who were to receive a lumbar puncture for routine clinical care in the emergency department were included. Target patient enrollment was set at 100. Patients were randomized to either undergo preprocedural ultrasonographic localization of the puncture site by the treating emergency physician or to have the puncture site determined by the usual landmark palpation method. Patients were assessed by the treating physician with respect to ease with which puncture-site landmarks could be palpated: easily palpable, difficult to palpate, or unable to palpate. The primary endpoint was success of the procedure as defined by return of cerebrospinal fluid; secondary endpoints were the number of needle passes, pain associated with the procedure, time to perform the procedure, and patient satisfaction with the procedure. The primary analysis compared use of ultrasonography versus palpation alone for all endpoints using the x2 test, Fisher’s exact test, and the Wilcoxon rank sum test, as appropriate. A subgroup analysis was performed by dividing patients into subgroups according to ease of landmark palpation. No consideration was given to terminating this study according to this interim analysis. Results: Sixty-six patients have been enrolled to date. Median age of the patients was 39 years, and 48% were men. Thirty-three (50%) of the patients were considered easy to palpate, 21 (32%) were difficult to palpate, and 12 (18%) were designated as having landmarks that were not palpable. Thirty-three (50%) patients were randomized into each of the 2 study groups. There were no significant differences between the 2 groups in terms of age, sex, body mass index, or ease of palpation of landmarks. For the primary outcome, procedural success, there were no significant differences between those undergoing ultrasonographic localization and those with palpation alone. The only secondary outcome that was significantly different was the median time to perform the procedure, with palpation at 2.8 minutes (interquartile ratio [IQR] 4.8 to 14.2) versus ultrasonography at 7.9 minutes (IQR 0.9 to 14.0; P=.03). Subgroup analysis showed that in the group of patients whose landmarks were either difficult to palpate or not palpable, there was a trend toward improved
OCTOBER 2004
44:4
ANNALS OF EMERGENCY MEDICINE
success rate using ultrasonography. Success rate for ultrasonography group was 100% (14 of 14) versus 84% for the palpation-only group (16 of 19; P=.24). In this subgroup, there were no significant differences between groups for number of needle attempts, pain scores, patient satisfaction, or time of procedure. Conclusion: Preliminary data do not suggest any advantage to the routine use of ultrasonography in patients who require lumbar puncture. There may be an improved success rate in those patients whose spinal landmarks are either difficult to palpate or not palpable. Use of ultrasonography for lumbar puncture localization adds 5.1 minutes to the median time required to perform the procedure.
271
Ultrasonographic Assessment of Bladder Volume Prior to Urinary Catheterization in Infants: Training Operators and Avoiding Unsuccessful Catheterizations
Milling T, Melville L, Santiago L, Van Amerongen R/New York Methodist Hospital, Brooklyn, NY Study objectives: Previous studies have shown a 10% failure rate in urine catheterization in children younger than 2 years. This leads either to an incomplete evaluation or a second procedure, with attendant discomfort for child and parent and increased risk of urethral trauma. We assess a brief educational intervention to teach pediatric and emergency medicine attending physicians and residents to use ultrasonography to measure a bladder index and attempt to define a minimum index predictive of successful catheterization. Methods: Investigators were given a 30-minute training session on identifying and measuring the urinary bladder with ultrasonography on volunteer patients. All sonograms were performed with a Sonosite iLook with 7.5-MgHz vascular probe. Female patients younger than 2 years and male patients younger than 1 year were enrolled prospectively in an urban pediatric emergency department during a 1month period. The physicians performing the catheterization were blinded to the sonographic results. Data recorded were demographics, anterior posterior and lateral bladder diameter, success in obtaining 2 mL of urine (the minimum needed to guarantee urine analysis and culture) and complicating factors. Bladder index was defined as the product of anterior posterior and lateral diameters, expressed in square centimeters. Assuming a perfect sphere, a bladder radius of approximately 0.75 cm would equal a volume of 2 mL. Using this model, the equivalent bladder index would be 2.2 cm2. We expect bladder indices roughly at or above this cutoff to be successful. Results: Twenty patients were enrolled, 11 of whom were girls, average age 7 months, average weight 19 pounds. More than 2 mL of urine were obtained in 16 (80%) patients. These patients had an average AP diameter of 1.9 cm (range 0.7 to 2.8 cm), a lateral diameter of 2.6 cm (range 2.0 to 4.3 cm), and an average bladder index of 4.9 cm2 (range 2.2 to 9.4 cm2). Two failures had anterior posterior diameters of 0.5 and 0 and lateral diameters of 0.5 and 0 (bladder indices of 0.25 and 0). The 2 remaining failures were ascribed to the child urinating during the procedure, and repeated catheterization was not performed. Conclusion: Our results indicate that emergency and pediatric attending physicians and residents can be quickly trained to use ultrasonography to assess infant urinary bladders and calculate a bladder index. Our data suggest that a bladder index of 2.2 cm2 can be used as a cutoff to predict successful catheterization.
272
Can Midlevel Providers Perform Ultrasonography on Superficial Abscesses?
Roppolo LP, Krakover B, Miller AH, Hatten B/University of Texas Southwestern, Dallas, TX Study objectives: Bedside ultrasonography has proven to be a useful adjunct in the diagnoses of abscesses. To date, there are no studies evaluating the utility of ultrasonography in diagnosing superficial abscesses by midlevel providers (physician assistants and nurse practitioners). We determine the ability of midlevel providers to identify superficial abscesses using bedside ultrasonography assessment. Methods: This is an institutional review board–approved, prospective, observational study of adult patients ([18 years) presenting to the emergency department (ED) with a suspected superficial abscess according to physical examination findings of localized swelling, redness, warmth, or fluctuance. The study was conducted in an urban university hospital with a census of more than 130,000 per year during a 6-month period. Bedside ultrasonography was performed
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