Welcome to the inaugural post for an exciting new ultrasound-based case series called “Ultrasound For The Win!” (#US4TW). In this peer-reviewed case series, we will focus on real clinical cases where bedside ultrasound changed the management or aided in the diagnosis. In our first case, we present a 28-year-old female with shortness of breath.
A 64 year old man with an extensive history of abdominal surgeries presents to the emergency department with abdominal pain and vomiting. Because you suspect a bowel obstruction, you bring an ultrasound machine to the bedside prior to the completion of any laboratory testing or other imaging. A curvilinear probe in the abdominal mode setting was used to scan in all four quadrants of the abdomen looking in both the sagittal and transverse planes.
Over the last several years, ALiEM has recruited a team of regular contributors, each with their own individual passions within the entire breadth of Emergency Medicine. ALiEM has provided these individuals with a global platform capable of carrying their message to a target audience of thousands of regular subscribers. Furthermore, the evolution of a rigorous pre-publication Expert Peer Review process has helped ensure that the content is especially polished and scientifically accurate.
Today marks a new day. The overwhelming success of the website and editorial process has led us to what we feel is the next step for this academic blog and online medical education: peer-reviewed community content submission.
Iron toxicity is determined by the amount of elemental iron (Fe) ingested. Examples of Fe formulations and the amount of elemental Fe contained in each formulation are listed in the table below (adapted from 1).
Local anesthetics (LAs) are widely employed to achieve tissue infiltration, peripheral and regional anesthesia, and neuraxial blockades. Despite their well-established toxic dose limits, these agents continue to pose a substantial risk of morbidity and mortality due to local anesthetic toxicity and overdose.
For example, LAs and epinephrine account for a large proportion of medication errors resulting in adverse patient outcomes due to drug dosing miscalculations or errors converting between units. Dosage calculations vary by patient weight as well as by pharmacokinetics and pharmacodynamics of individual LA formulations. Further, non-standard units, additives (epinephrine), and varying concentrations among LAs complicate correct dosage derivations.
In an effort to curb calculation errors and avert LA toxicity, Williams and Walker derived a helpful nomogram1 to calculate the maximum, weight-based volume of commonly used LAs (lidocaine, prilocaine, bupivacaine, and ropivacaine). This nomogram was validated against a calculator in the original article. Please note that while this nomogram may aid in dosage verification, there is no substitute for a second, independent derivation of the total maximum dose using a different method, as an additional safeguard to prevent dosage error.
LA toxicity presents clinically as a constellation of symptoms including, but not limited to, tinnitus, circumoral tingling, metallic taste, and dizziness. Severe manifestations include altered mentation, arrhythmias, and cardiovascular collapse. Management is predicated upon stopping the offending agent, providing supportive measures, and administering weight-based intravenous 20% lipid emulsion. The authors, Williams and Walker, derived a separate nomogram to guide treatment by calculating the appropriate weight-based lipid therapy, specifying the initial bolus amount, infusion rate, and total maximum dose of lipid emulsion.
Both the toxicity and lipid emulsion nomograms are displayed in this Paucis Verbis card.
The Devine formulation is the most commonly accepted calculation (most applicable for people at least 60 inches, or 5 feet, tall):
See the MDCalc calculator for IBW.