Management of Patients with Predicted Difficult Airways in an Academic Emergency Department.

BACKGROUND: Patients with difficult airways are sometimes encountered in the emergency department (ED), however, there is a little data available regarding their management. OBJECTIVES: To determine the incidence, management, and outcomes of patients with predicted difficult airways in the ED. METHODS: Over the 1-year period from July 1, 2015 to June 30, 2016, data were prospectively collected on all patients intubated in an academic ED. After each intubation, the operator completed an airway management data form. Operators performed a pre-intubation difficult airway assessment and classified patients into routine, challenging, or difficult airways. All non-arrest patients were included in the study. RESULTS: There were 456 patients that met inclusion criteria. Fifty (11%) had predicted difficult airways. In these 50 patients, neuromuscular blocking agents (NMBAs) were used in 40 (80%), an awake intubation technique with light sedation was used in 7 (14%), and no medications were used in 3 (6%). In the 40 difficult airway patients who underwent NMBA facilitated intubation, a video laryngoscope (GlideScope 21, Verathon, Bothell, WA and C-MAC 19, Karl Storz, Tuttlingen, Germany) was used in each of these, with a first-pass success of 90%. In the 7 patients who underwent awake intubation, a video laryngoscope was used in 5, and a flexible fiberoptic scope was used in 2. Ketamine was used in 6 of the awake intubations. None of these difficult airway patients required rescue with a surgical airway. CONCLUSIONS: Difficult airways were predicted in 11% of non-arrest patients requiring intubation in the ED, the majority of which were managed using an NMBA and a video laryngoscope with a high first-pass success.

Detection of in vivo enzyme activity with CatalyCEST MRI.

PURPOSE: CatalyCEST MRI compares the detection of an enzyme-responsive chemical exchange saturation transfer (CEST) agent with the detection of an unresponsive "control" CEST agent that accounts for other conditions that influence CEST. The purpose of this study was to investigate the feasibility of in vivo catalyCEST MRI. METHODS: CEST agents that were responsive and unresponsive to the activity of urokinase plasminogen activator were shown to have negligible interaction with each other. A CEST-fast imaging with steady state precession (FISP) MRI protocol was used to acquire MR CEST spectroscopic images with a Capan-2 pancreatic tumor model after intravenous injection of the CEST agents. A function of (super)-Lorentzian line shapes was fit to CEST spectra of a region-of-interest that represented the tumor. RESULTS: The CEST effects from each agent showed the same initial uptake into tumor tissues, indicating that both agents had the same pharmacokinetic transport rates. Starting 5 min after injection, CEST from the enzyme-responsive agent disappeared more quickly than CEST from the unresponsive agent, indicating that the enzyme responsive agent was being catalyzed by urokinase plasminogen activator, while both agents also experienced net pharmacokinetic washout from the tumor. CONCLUSION: CatalyCEST MRI demonstrates that dynamic tracking of enzyme-responsive and unresponsive CEST agents during the same in vivo MRI study is feasible.