Amy L. Baxter

Local anesthetic and stylet styles: factors associated with resident lumbar puncture success.

OBJECTIVE. To assess the effects of procedural techniques, local anesthetic use, and postgraduate training level on lumbar puncture (LP) success rates. METHODS. In this prospective observational study, medical students and residents (“trainees”) reported techniques used for infant LPs in an urban teaching emergency department. Data on postgraduate year, patient position, draping, total and trainee numbers of attempts, local anesthetic use, and timing of stylet removal were collected. Logistic regression analysis was used to identify predictors of successful LP, with success defined as the trainee obtaining cerebrospinal fluid with <1000 red blood cells per mm3. RESULTS. We collected data on 428 (72%) of 594 infant LPs performed during the study period. Of 377 performed by trainees, 279 (74%) were successful. Local anesthesia was used for 280 (74%), and 225 (60%) were performed with early stylet removal. Controlling for the total number of attempts, LPs were 3 times more likely to be successful among infants >12 weeks of age than among younger infants (odds ratio [OR]: 3.1; 95% confidence interval [CI]: 1.2–8.5). Controlling for attempts and age, LPs performed with local anesthetic were twice as likely to be successful (OR: 2.2; 95% CI: 1.04–4.6). For infants ≤12 weeks of age, early stylet removal improved success rates (OR: 2.4; 95% CI: 1.1–5.2). Position, drape use, and year of training were not significant predictors of success. CONCLUSIONS. Patient age, use of local anesthetic, and trainee stylet techniques were associated with LP success rates. This offers an additional rationale for pain control. Predictors identified in this study should be considered in the training of physicians, to maximize their success with this important procedure.

Emergency Physician–Administered Propofol Sedation: A Report on 25,433 Sedations From the Pediatric Sedation Research Consortium

STUDY OBJECTIVE We describe the adverse events observed in a large sample of children sedated with propofol by emergency physicians and identify patient and procedure characteristics predictive of more serious adverse events. METHODS We identified sedations performed by emergency physicians using propofol as the primary sedative, included in the Pediatric Sedation Research Consortium database from July 2004 to September 2008. We describe the characteristics of the patients, procedures, location, adjunctive medications, and adverse events. We use a multivariable logistic regression model to identify predictors of more serious adverse events. RESULTS Of 25,433 propofol sedations performed by emergency physicians, most (76%) were performed in a radiology department. More serious adverse events occurred in 581 sedations (2.28%; 95% confidence interval 2.1% to 2.5%). There were 2 instances of aspiration, 1 unplanned intubation, and 1 cardiac arrest. Significant predictors of serious adverse events were weight less than or equal to 5 kg, American Society of Anesthesiologists classification greater than 2, adjunctive medications (benzodiazepines, ketamine, opioids, or anticholinergics), nonpainful procedures, and primary diagnoses of upper respiratory illness or prematurity. CONCLUSION We observed a low adverse event prevalence in this largest series of propofol sedations by emergency physicians. Factors indicating greater risk of more serious adverse events are detailed.

Development and validation of a pictorial nausea rating scale for children.

OBJECTIVE: The lack of a widely used, validated measure limits pediatric nausea management. The goal of this study was to create and validate a pictorial scale with regular incremental levels between scores depicting increasing nausea intensity. METHODS: A pictorial nausea scale of 0 to 10 with 6 faces (the Baxter Retching Faces [BARF] scale) was developed in 3 stages. The BARF scale was validated in emergency department patients with vomiting and in healthy patients undergoing day surgery procedures. Patients were presented with visual analog scales for nausea and pain, the pictorial Faces Pain Scale–Revised, and the BARF scale. Patients receiving opioid analgesics or antiemetic agents had their pain and nausea assessed before and 30 minutes after therapy. Spearmans ρ correlation coefficients were calculated. A Wilcoxon matched-pair rank test compared pain and nausea scores before and after antiemetic therapy. RESULTS: Thirty oncology patients and 15 nurses participated in the development of the scale, and 127 patients (52, emergency department; 75, day surgery) ages 7 to 18 years participated in the validation. The Spearman ρ correlation coefficient of the first paired BARF and visual analog scale for nausea scores was 0.93. Visual analog scales for nausea and BARF scores (P = .20) were significantly higher in patients requiring antiemetic agents and decreased significantly after treatment, while posttreatment pain scores (P = .47) for patients receiving only antiemetic agents did not. CONCLUSIONS: We describe the development of a pictorial scale with beginning evidence of construct validity for a self-report assessment of the severity of pediatric nausea. The scale had convergent and discriminant validity, along with an ability to detect change after treatment.

Pain, position, and stylet styles: infant lumbar puncture practices of pediatric emergency attending physicians.

Objectives: Lumbar punctures (LPs) are common emergency department (ED) procedures. Few pediatric studies exist to define training, guide practice, or indicate preferred methods for infants. While pain control is recommended, no recent studies indicate prevalence of analgesic use since the advent of topical anesthetics. We surveyed academic pediatric ED physicians to assess training and technique preferences and to highlight pain control usage. Methods: A total of 398 physicians were randomly selected from the 621 e-mail accessible members of the AAP Section on Pediatric Emergency Medicine. Questions concerning physician training, analgesia, and technique were either sent by regular mail or via e-mail link to a Web-based survey. Results: Of 359 deliverable surveys, there were 188 physician responses (52.4%) with differential response rates by survey format [58 e-mail (36%) and 130 regular mail responses (66%); P < 0.05]. Almost a third will advance the needle without the stylet in place. Two-thirds of physicians do not routinely use analgesia for neonatal LPs. Those using pain control were trained more recently (median 12 years vs. 15 years postresidency; P = 0.04). Analgesia use was the most common practice changed since residency. Conclusions: Analgesia is underused for infant LPs. Advancing the needle without a stylet is not uncommon. Response rate to regular mail surveys was much higher.

Mass screening for fever in children: a comparison of 3 infrared thermal detection systems.

Objectives Infrared thermal detection systems (ITDSs) have been used with limited success outside the United States to screen for fever during recent outbreaks of novel infectious diseases. Although ITDSs are fairly accurate in detecting fever in adults, there is little information about their utility in children. Methods In a pediatric emergency department, we compared temperatures of children (<18 years old) measured using 3 ITDSs (OptoTherm Thermoscreen, FLIR ThermoVision 360, and Thermofocus 0800H3) to standard, age-appropriate temperature measurements (confirmed fever defined as ≥38.0°C [oral or rectal], ≥37.0°C [axillary]). Measured temperatures were compared with parental reports of fever using descriptive, multivariate, and receiver operating characteristic analyses. Results Of 855 patients, 400 (46.8%) had parent-reported fever, and 306 (35.8%) had confirmed fever. At optimal fever thresholds, OptoTherm and FLIR had sensitivity (83.0% and 83.7%, respectively) approximately equal to parental report (83.9%) and greater than Thermofocus (76.8%), and specificity (86.3% and 85.7%) greater than parental report (70.8%) and Thermofocus (79.4%). Correlation coefficients between traditional thermometry and ITDSs were 0.78 (OptoTherm), 0.75 (FLIR), and 0.66 (Thermofocus). Conclusions Compared with traditional thermometry, FLIR and OptoTherm were reasonably accurate in detecting fever in children and better predictors of fever than parental report. These findings suggest that ITDSs could be a useful noninvasive screening tool for fever in the pediatric age group.

Effect of MRI strength and propofol sedation on pediatric core temperature change.

To determine core body temperature variations in children undergoing MRI exams on 1.5 Tesla (T) and 3T magnetic field strengths and with and without propofol sedation.

Concerns with the methodology, analysis and discussion of the Buzzy® and transillumination comparison article

In the article by Dr. Lima-Oliveira et al., “A new device to relieve venipuncture pain can affect haematology test results”1, prolonged application of a Buzzy®/ice pack unit with the elastic tourniquet included resulted in different laboratory values from those in free-flowing blood collected with transillumination. As the physician inventor and manufacturer of the Buzzy® device, I appreciate the opportunity to respond to the findings, clarify appropriate use of our product, and illuminate a source of bias not considered in the discussion. As laboratory analysis and procedures are an integral part of the discussion, a statistician familiar with comparative sample methodology has reviewed the work as well. Buzzy® (MMJ Labs LLC, Atlanta, GA, Unites States of America) combines high frequency vibration with an optional ice pack; the healthcare version tested in this study came with an elastic black Velcro tourniquet to attach Buzzy® to the arm. When placed immediately prior to venipuncture Buzzy® has been shown to decrease pain significantly in adults without compromising the success of venous access2. In children, Buzzy® decreased pain by half compared to that present when a cold spray was used, and increased the likelihood of obtaining blood at the first attempt3,4. In contrast to the statements made in the article, we have no data to support that the pain relief will “enhance patients’ compliance during venous blood collection”, although Buzzy® has been used to enhance compliance with burning injections5. Our instructions state that Buzzy ®should be applied “immediately before cleaning and inserting IV”. In contrast to recommending 15 to 60 seconds of direct application to relieve the pain of IM (intramuscular) injections, the package insert notes that “direct or prolonged application of ice could vasoconstrict or alter lab values”. The theoretical concerns of both vasoconstriction and triggering cold agglutinins do not support prolonged application of Buzzy®, and we are concerned that the article by Lima-Oliveira et al. supports an incorrect usage of the device. The article indicates that Buzzy® was correctly placed 5 cm above the puncture site, but does not specify how Buzzy® was held in place. An article published by the same authors 2 months earlier compares Buzzy® to the same brand of transilluminator for blood chemistry evaluation, and uses the same sentences to describe methodology, including fasting, blood draw order, sequence, needle gauge, and 2 mL wastage. It is not stated in either paper whether Buzzy® is applied with the black elastic tourniquet strap; however in the chemistry paper a picture shows the application with the black tourniquet elastic constricting a patient’s arm. It is not clear in either paper whether Buzzy® was applied first for 1 minute, then blood was drawn from the opposite side using the transilluminator, then subsequently blood was drawn from the Buzzy® side. Depending on the procedure, the total Buzzy® application time would be between 90 and 180 seconds. The methods do specify that the transilluminator device was applied without a tourniquet. It is clear that there was no randomisation between whether blood was drawn first from the right or left arm. In all cases blood was drawn from the transilluminator side first, introducing order of draw as a potential confounder. There were few significant differences between the laboratory results between the two methods, even with a highly powered paired design. The differences found echoed the differences Dr. Lima-Oliveira reported in a previous paper comparing a tourniquet vs the transilluminator device for the collection of blood. According to the 2011 tourniquet/transilluminator paper6, when a tourniquet was left in place for 90 seconds significant differences were found in red blood cell counts, haemoglobin concentration, haematocrit, as well as eosinophils and basophils. In the Buzzy/transilluminator paper, differences were found in red blood cell count, haemoglobin concentration and haematocrit. It seems logical that the major differences between Buzzy® and the transilluminator may be largely due to the black elastic tourniquet, and not to the Buzzy. The authors state that “there is a tangible risk that some physicians could make inappropriate clinical decisions, e.g. delay or avoid RBC transfusions” due to the differences in laboratory values. They base this potential clinical risk on a 2.5% difference in haemoglobin (141.4 g/L vs 137.9 g/L) or a haematocrit difference of 2.2% (41.5 vs 40.6). The Authors neglect to mention that in their own comparisons between the transilluminator device and application of a tourniquet for 90 seconds, the haemoglobin and haematocrit differences were greater than those in the Buzzy®/transilluminator comparison (2.6% and 2.9%, respectively) (Table I). Following this logic, use of the transilluminator would be even more likely to contribute to the same dire clinical results when compared to the gold standard of tourniquet use, yet the authors praise the transilluminator in their previous articles and refer to it as the “gold standard” in their Buzzy® comparison papers. Table I Comparison between values in blood collected using a transilluminator (trans) and Buzzy® left 90–180 seconds1, and a transilluminator and tourniquet left 90 seconds6, with mean difference between paired results. Items in bold are statistically ... As a clinician, the most important finding comes from comparing the two transilluminator studies. While the prolonged tourniquet application caused platelet, white blood cell and neutrophil counts to increase by 4.8%, 4.2% and 3.6%, respectively (P=NS), in the Buzzy® study they fell by 2.9%, 3.9%, and 0.8%. The fact that these differences were not statistically significant in a paired evaluation may mean the differences were not clinically relevant, but this finding is worth reporting as many paediatric clinics may use Buzzy® when determining whether a patient is neutropenic. These results would cause a clinician to err conservatively, but are worth knowing in a worst-case application scenario. Because the Buzzy®/transilluminator paper does not mention the previous tourniquet/transilluminator paper, this result is not emphasised. For their analysis, Dr. Lima-Oliveira et al. used as a standard the allowed bias for laboratory quality control, and appear to have extrapolated that these constitute clinically significant differences. In laboratory quality control, multiple analyses of the same sample are run and compared to a reference database for optimal minimum differences, which are not generally achieved in the clinical laboratory setting7. According to the authors of the reference database Lima-Oliveira cites, there is a measure appropriate for clinical differences. Specifically, “The numerical value that delineates medically significant changes between two results, classically named “critical difference”8 and today called Reference Change Value (RCV), comes from the formula: RCV=k×2×CVA2+CVI2 with k=1.65 for a one tail test and a probability risk α of 95%, and CVA and CVI the analytical and the within-subject (or intra-individual) coefficients of variation, respectively9. It is unclear why this value was not used or at least reported, as it would provide the clinician with vital information that the “desired bias” values do not. While both transilluminator papers refer to the device as the “gold standard”, traditional laboratory value textbooks presumably used tourniquet samples rather than this new transilluminator device. As such, the term “gold standard” is possibly premature. Finally, the discussion of the effect of compression by Buzzy’s elastic tourniquet is absent. Dr. Lima-Oliveira has published five papers discussing the differences between constricted blood draws and free flowing blood draws using the transilluminator device, made in Brazil near his laboratory. For this reason, omission of the discussion of the contribution of prolonged tourniquet application is perplexing, as the papers were published prior to the current Buzzy®/transilluminator article. Given the use of Buzzy® against package insert instructions, lack of full discussion of methods, the knowledge that tourniquet compression causes greater laboratory changes than those found in the Buzzy® study, and the choice of analytic methods, the conclusion that “the novel Buzzy® device should be used with caution,” seems excessive and inexplicably biased. The knowledge that few laboratory values were in any way clinically different despite the prolonged application is useful, and we appreciate the time of the author in conducting this study.

Imaging for Suspected Appendicitis: Variation Between Academic and Private Practice Models.

Background Little is known regarding the effect of different emergency department (ED) practice models on computed tomography (CT) and ultrasound (US) utilization for suspected appendicitis in the ED and through the potential inpatient hospital stay. Objectives Examination rates of CT and US for suspected appendicitis at 2 different pediatric EDs (PEDs) through hospital admission: an academic affiliated tertiary PED (site A) compared with a private practice tertiary care PED (site B). Methods All visits with the ICD-9 (International Classification of Diseases, Ninth Revision) chief complaint of abdominal pain were retrospectively examined from May 1, 2009, to February 21, 2012. Suspected appendicitis visits were defined as any visit with the chief complaint of abdominal pain where a complete blood cell count was obtained. Abdominal CT and US in the PED and during hospital admission were compared across the 2 sites. Return visits within 72 hours were evaluated for any missed appendicitis. Results Overall appendicitis rates were similar at both sites: site A, 4.7%; site B, 4.0%. The odds of having a CT scan performed during visits to the PED for abdominal pain were significantly higher at site B (odds ratio [OR], 3.19; 95% confidence interval [95% CI], 2.74–3.71), whereas the odds of having an US at site B were the opposite (OR, 0.34; 95% CI, 0.28–0.40). When evaluating only the admitted visits, the odds of having a CT were also greater at site B (OR, 2.32; 95% CI, 1.86–2.94) and having an US were less (OR, 0.57; 95% CI, 0.44–0.73). Conclusions In this study of 2 PEDs with differing practice models, we identified a dramatic difference in imaging utilization among patients with suspected appendicitis.

Factors Associated With Lumbar Puncture Success: In Reply

In Reply .— We thank Drs Molina and Fons for their interest in our article on resident success of lumbar puncture (LP) and for sharing their data regarding the width of the intravertebral space of infants in the sitting versus the supine position. Their ultrasound results may influence the common debate of sitting versus recumbent position. Position did not remain in our model for efficacy …