Michael D. Witting

Laboratory testing in ethanol, methanol, ethylene glycol, and isopropanol toxicities☆

Toxicity from ethanol, methanol, ethylene glycol, and isopropyl alcohol varies widely, and appropriate use of the available laboratory tests can aid in timely and specific treatment. Available testing includes direct measurements of serum levels of these alcohols; however, these levels often are not available rapidly enough for clinical decision making. This article discusses the indications and methods for both direct and indirect testing for ethanol, methanol, ethylene glycol, and isopropanol toxicity. Also discussed are the costs, availability, and turn-around times for these tests.

Does Exogenous Melatonin Improve Day Sleep or Night Alertness in Emergency Physicians Working Night Shifts

STUDY OBJECTIVE To determine whether exogenous melatonin improves day sleep or night alertness in emergency physicians working night shifts. METHODS In a double-blind, placebo-controlled crossover trial, emergency physicians were given 10 mg sublingual melatonin or placebo each morning during one string of nights and the other substance during another string of nights of equal duration. During day-sleep periods, subjective sleep data were recorded. During night shifts, alertness was assessed with the use of the Stanford Sleepiness Scale. Key outcome comparisons were visual analog scale scores for gestalt night alertness and for gestalt day sleep for the entire string of nights. RESULTS We analyzed data from 18 subjects. Melatonin improved gestalt day sleep (P = .3) and gestalt night alertness (P = .03) but in neither case was the improvement statistically significant. Of 13 secondary comparisons, 9 showed a benefit of melatonin over placebo; none showed a benefit of placebo over melatonin. CONCLUSION Exogenous melatonin may be of modest benefit to emergency physicians working night shifts.

Effects of Vein Width and Depth on Ultrasound-Guided Peripheral Intravenous Success Rates

BACKGROUND Increasing numbers of operators are learning to use ultrasound to guide peripheral intravenous (i.v.) catheter insertion in patients with difficult access. Unfortunately, failed cutaneous punctures are common. Some veins seen on ultrasound may be better choices than others. OBJECTIVES To estimate the effects of vein width and depth on the probability of success in ultrasound-guided i.v. catheter insertion. METHODS We prospectively collected data from attempts at ultrasound-guided venous catheter insertion between the antecubital fossa and mid-humerus. Each ultrasound machines ruler function was used to determine depth from the skin to the closest vein edge and that veins largest diameter. Success was defined as being able to freely withdraw blood or inject saline after the first skin puncture, considering each encounter independently. We calculated relative success rates, confidence intervals, and p values using reference groups selected by histogram analysis. RESULTS Thirty-five operators recorded 180 encounters; 100 (56%) were successful on the first skin puncture, and 152 (84%) were eventually successful. Success rates were not linearly related to vein width or depth. Success rates were higher for veins with diameter > or = 0.4 cm vs. those < 0.4 cm (63% [78/124] vs. 39% [22/56], relative success 1.6 [95% confidence interval (CI) 1.1-2.3], p = 0.005) and for veins of depth 0.3-1.5 cm vs. veins of depth < 0.3 or > 1.5 cm (58% [96/165] vs. 27% [4/15], relative success 2.2 [95% CI 0.9-5.1], p = 0.04). CONCLUSION Success rates are higher in larger veins (> or = 0.4 cm) and veins at moderate depth (0.3-1.5 cm).

A Comparison of Emergency Medicine Ultrasound Training With Guidelines of the Society for Academic Emergency Medicine

STUDY OBJECTIVES To compare the current state of emergency medicine residency ultrasound training with guidelines for that training from the Society for Academic Emergency Medicine (SAEM). METHODS A brief questionnaire was sent to program directors from 119 emergency medicine residency programs in the United States. Responses were compared with the SAEM guidelines for clinical experience (150 total ultrasounds) and didactic experience (40 hours of didactic instruction). RESULTS The overall response rate was 92%. Seventy-six (69%) of the programs own an ultrasound machine (ownership defined as 24-hour availability and complete discretion over use). Of these, 12 (16%) indicated that their average 1998 graduate had done at least 150 total ultrasound scans during residency, although none of the programs had average numbers that exceeded the minimum guidelines for all 4 procedure categories. Information on didactic curriculum was available from 74 ultrasound-owning programs: the duration was 0 to 20 hours in 49 (66%), 20 to 40 hours in 19 (26%), and 40 to 100 hours in 6 (8%). Only 1 programs average graduate met or exceeded the SAEM guidelines for both didactic and clinical training. CONCLUSION Most emergency medicine residency programs own at least 1 ultrasound machine, with more than half of these obtaining their first machine within the past 3 years. Only 1 program currently meets SAEM training guidelines.

Prevention of Pediatric Drug Calculation Errors by Prehospital Care Providers

Objective. Calculating weight-based drug doses for pediatric patients is difficult, with significant error potential. In the prehospital setting, few safeguards currently avert pediatric drug administration errors. We sought to determine whether use of a protocol-specific pediatric code card enables prehospital care providers to calculate more consistently accurate weight-based drug doses, volumes of administration, andage-appropriate endotracheal tube sizes. Methods. Questionnaires requiring calculations of medication doses, volumes, andendotracheal tube sizes were administered to prehospital care providers between June andNovember 2006 in fire department continuing education classes in the State of Maryland andthe District of Columbia. Half of the participants performed the calculations with the pediatric code card as an aid, andhalf without. Calculations done by the two groups were compared for rate andextent of errors. We evaluated the error frequency in calculations of pediatric medication doses andendotracheal tube sizes. Results. Of the 523 advanced life support prehospital care providers questioned, 246 answered questions using the pediatric code card, and277 answered questions without using the card. The mean individual percentages of correct responses were 94% for the group aided by the code card and65% for the group unaided by the card (percentage difference, 29%; 95% confidence interval [CI], 25–31%; p < 0.001). Ninety-eight percent of the aided group and23% of the unaided group calculated the correct endotracheal tube size (percentage difference, 75%; 95% CI, 70–81%; p < 0.001). Conclusions. The use of the pediatric code card enabled prehospital care providers to determine weight-based drug doses, volumes of administration, andendotracheal tube sizes more accurately than peers without access to the code card.

A comparison of longitudinal and transverse approaches to ultrasound-guided axillary vein cannulation☆ , ☆☆ , ☆☆☆ , ☆☆☆☆ ,★,★★,★★★

OBJECTIVE The axillary vein is an easily accessible vessel that can be used for ultrasound-guided central vascular access and offers an alternative to the internal jugular and subclavian veins. The objective of this study was to identify which transducer orientation, longitudinal or transverse, is better for imaging the axillary vein with ultrasound. METHODS Emergency medicine physicians at an inner-city academic medical center were asked to cannulate the axillary vein in a torso phantom model. They were randomized to start with either the longitudinal or transverse approach and completed both sequentially. Participants answered questionnaires before and after the cannulation attempts. Measurements were taken regarding time to completion, success, skin punctures, needle redirections, and complications. RESULTS Fifty-seven operators with a median experience of 85 ultrasound procedures (interquartile range, 26-120) participated. The frequency of first-attempt success was 39 (0.69) of 57 for the longitudinal method and 21 (0.37) of 57 for the transverse method (difference, 0.32; 95% confidence interval [CI], 0.12-0.51 [P = .001]); this difference was similar regardless of operator experience. The longitudinal method was associated with fewer redirections (difference, 1.8; 95% CI, 0.8-2.7 [P = .0002]) and skin punctures (difference, 0.3; 95% CI, -2 to +0.7 [P = .07]). Arterial puncture occurred in 2 of 57 longitudinal and 7 of 57 transverse attempts; no pleural punctures occurred. For successful attempts, the time spent was 24 seconds less for the longitudinal method (95% CI, 3-45 [P = .02]). CONCLUSIONS The longitudinal method of visualizing the axillary vein during ultrasound-guided venous access is associated with greater first-attempt success, fewer needle redirections, and a trend of fewer arterial punctures compared with the transverse orientation.

Ultrasound use during cardiopulmonary resuscitation is associated with delays in chest compressions

AIM High-quality chest compressions are a critical component of the resuscitation of patients in cardiopulmonary arrest. Point-of-care ultrasound (POCUS) is used frequently during emergency department (ED) resuscitations, but there has been limited research assessing its benefits and harms during the delivery of cardiopulmonary resuscitation (CPR). We hypothesized that use of POCUS during cardiac arrest resuscitation adversely affects high-quality CPR by lengthening the duration of pulse checks beyond the current cardiopulmonary resuscitation guidelines recommendation of 10s. METHODS We conducted a prospective cohort study of adults in cardiac arrest treated in an urban ED between August 2015 and September 2016. Resuscitations were recorded using video equipment in designated resuscitation rooms, and the use of POCUS was documented and timed. A linear mixed-effects model was used to estimate the effect of POCUS on pulse check duration. RESULTS Twenty-three patients were enrolled in our study. The mean duration of pulse checks with POCUS was 21.0s (95% CI, 18-24) compared with 13.0s (95% CI, 12-15) for those without POCUS. POCUS increased the duration of pulse checks and CPR interruption by 8.4s (95% CI, 6.7-10.0 [p<0.0001]). Age, body mass index (BMI), and procedures did not significantly affect the duration of pulse checks. CONCLUSIONS The use of POCUS during cardiac arrest resuscitation was associated with significantly increased duration of pulse checks, nearly doubling the 10-s maximum duration recommended in current guidelines. It is important for acute care providers to pay close attention to the duration of interruptions in the delivery of chest compressions when using POCUS during cardiac arrest resuscitation.

The ability of pulse oximetry to screen for hypoxemia and hypercapnia in patients breathing room air

This study was designed to determine whether high room-air pulse oximetry can rule out hypoxemia or moderate hypercapnia. Based on retrospective analysis of 513 arterial blood gas results, oxygen saturation cutpoints were derived. Coincidentally, a room-air oxygen saturation (RAO2 sat) value of 96% was selected as a cutpoint to screen for both hypoxemia (PaO2 < 70 mm Hg) and moderate hypercapnia (PaCO2 > 50 mm Hg). These tests were validated prospectively by using a convenience sample of 213 Emergency Department patients in whom room-air arterial blood gas sampling was ordered. To detect hypoxemia, the sensitivity of RAO(2) sat < or = 96% was 1.0 [0.95-1.0, 95% confidence interval (CI)] and specificity was 0.54 (0.45-0.64, 95% CI). To detect hypercapnia, the sensitivity of RAO(2) sat < or = 96% was 1.0 (0.7-1.0) and specificity was 0.31 (0.25-0.38, 95% CI). We concluded that RAO(2) sat > or = 97% rules out hypoxemia and may also rule out moderate hypercapnia.

Defining the positive tilt test: a study of healthy adults with moderate acute blood loss.

STUDY OBJECTIVES To define a set of orthostatic vital signs that minimize the frequency of false-positives among healthy individuals while maximizing sensitivity in detecting acute moderate blood loss and to determine the sensitivity and specificity of this optimized tilt test in detecting acute moderate blood loss. DESIGN AND INTERVENTION Postural vital signs were recorded in a standardized manner before and after 450-mL phlebotomy. Paired comparisons were done for a variety of criteria for a positive tilt test using receiver-operating characteristic curves. SETTING AND TYPE OF PARTICIPANTS Three hundred forty-five healthy euvolemic adult volunteer blood donors were tested at three community blood donation centers over a one-year period. Subjects were prospectively divided into group 1 (less than age 65; 301) and group 2 (age 65 or older; 44). MEASUREMENTS AND MAIN RESULTS For each combination of pulse and blood pressure in group 1, a change in pulse alone had the same or higher sensitivity with at least the same specificity. Pulse alone was similarly superior in group 2 compared with previously published combinations of pulse and blood pressure. Even the optimized tilt test had limited sensitivity in detecting acute moderate blood loss with high specificity. CONCLUSION In applying the tilt test to young adults without cardiovascular disease, pulse measurement usually is all that is necessary.

Support for Emergency Department Screening for Intimate Partner Violence Depends on Perceived Risk

Emergency department (ED) screening for intimate partner violence (IPV) faces logistic difficulties and has uncertain efficacy. We surveyed 146 ED visitors and 108 ED care providers to compare their support for ED IPV screening in three hypothetical scenarios of varying IPV risk. Visitor support for screening was 5 times higher for the high-risk (86%) than for the low-risk (17%) scenario. Providers showed significantly more support for the need for ED IPV screening than visitors. Controlling for confounding by gender, race, experience with IPV, hospital, and marital status did not affect comparisons between groups. These responses indicate greater support for IPV screening in the ED for high-risk than for low-risk cases, particularly among visitors.