Airway Involvement and Intervention in Non-ACE-Inhibitor-Induced Angioedema.

OBJECTIVES: Characterize the presentation of patients with non-angiotensin-converting enzyme inhibitor (ACEI)-induced angioedema and determine risk factors associated with patient disposition and possible need for airway intervention. METHODS: The medical records of adult patients in the Emergency Department (ED) and diagnosed with non-ACEI-induced angioedema over 4.5 years were included. Demographics, vital signs, etiology, timeline, presenting symptoms, physical exam including flexible laryngoscopy, medical management, and disposition were examined. Statistical analyses were conducted using SPSS V 23.0 software calculating and comparing means, standard deviations, medians, and correlation of categorical and ordinate variables. RESULTS: A total of 181 patients with non-ACEI-induced angioedema were evaluated with flexible laryngoscopy by otolaryngology. Notably, 11 patients (6.1%) required airway intervention and were successfully intubated. Statistically significant factors (p ≤ 0.05) associated with airway intervention included the diastolic blood pressure (DBP) and mean arterial pressure (MAP) (p = 0.006 and 0.01 respectively), symptoms of dysphonia (p = 0.018), the presence of oropharyngeal, supraglottic, and hypopharyngeal edema (p ≤ 0.001 for each site), and the number of edematous anatomic subsites documented on physical exam (p < 0.001). Other patient demographics, prior history of angioedema, heart rate, systolic blood pressure, symptom onset, number of symptoms at presentation, and medication administered in the ED did not correlate with airway intervention. CONCLUSION: Dysphonia, DBP, MAP, anatomic location of edema and edema in multiple sites are associated with airway intervention and a higher level of care in non-ACEI-induced angioedema and can be useful in risk assessment in patient management. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:2282-2287, 2024.

Detection of Arytenoid Dislocation Using Pixel-valued Cuneiform Movement.

OBJECTIVES: This study aims to assess utility of pixel-valued movement software in detecting arytenoid dislocation preoperatively. STUDY DESIGN: This is a retrospective analysis. METHODS: Twenty-seven patients diagnosed with unilateral arytenoid dislocation were included. Diagnosis of arytenoid dislocation was confirmed by lack of vocal fold paralysis on preoperative laryngeal electromyography and by intraoperative findings of cricoarytenoid dislocation. A region-tracking software algorithm developed by Zhuang et al was used to analyze 27 preoperative endoscopic videos of patients diagnosed with arytenoid dislocation. Vector analysis measuring cuneiform movement during inspiration was used as an indirect measure of arytenoid movement. Values were normalized using vocal fold length. Two raters blinded to diagnosis of arytenoid dislocation measured vocal fold length and cuneiform movement on both the dislocated and the nondislocated sides. RESULTS: A Wilcoxon signed-rank test indicated that the mean pixel-valued cuneiform movement and standard deviation (SD) were greater for nondislocated (159.24, SD = 73.35) than for dislocated (92.49, SD = 72.11) arytenoids (Z = 3.29, P = 0.001). The interrater correlation coefficient was 0.87 for the dislocated side and 0.75 for the nondislocated side. The intrarater correlation coefficient was 0.87 for the dislocated side and 0.91 for the nondislocated side. The receiver operating characteristic curve revealed an area under the curve between 0.76 and 0.83 (95% confidence interval 0.63-0.90). Analysis by the first and second raters revealed misdiagnosis of laterality of arytenoid dislocation in four and six patients, respectively. CONCLUSIONS: The software program developed by Zhuang et al provides a high-degree of precision, with good interrater and intrarater correlation coefficients. However, high rates of misdiagnosis of arytenoid dislocation and the laborious analysis process using this software program make it of limited utility as a clinical diagnostic tool in its present state.

Modeling the effects of extracellular potassium on bursting properties in pre-Bötzinger complex neurons.

There are many types of neurons that intrinsically generate rhythmic bursting activity, even when isolated, and these neurons underlie several specific motor behaviors. Rhythmic neurons that drive the inspiratory phase of respiration are located in the medullary pre-Bötzinger Complex (pre-BötC). However, it is not known if their rhythmic bursting is the result of intrinsic mechanisms or synaptic interactions. In many cases, for bursting to occur, the excitability of these neurons needs to be elevated. This excitation is provided in vitro (e.g. in slices), by increasing extracellular potassium concentration (K out) well beyond physiologic levels. Elevated K out shifts the reversal potentials for all potassium currents including the potassium component of leakage to higher values. However, how an increase in K out , and the resultant changes in potassium currents, induce bursting activity, have yet to be established. Moreover, it is not known if the endogenous bursting induced in vitro is representative of neural behavior in vivo. Our modeling study examines the interplay between K out, excitability, and selected currents, as they relate to endogenous rhythmic bursting. Starting with a Hodgkin-Huxley formalization of a pre-BötC neuron, a potassium ion component was incorporated into the leakage current, and model behaviors were investigated at varying concentrations of K out. Our simulations show that endogenous bursting activity, evoked in vitro by elevation of K out , is the result of a specific relationship between the leakage and voltage-dependent, delayed rectifier potassium currents, which may not be observed at physiological levels of extracellular potassium.

Mechanisms of left-right coordination in mammalian locomotor pattern generation circuits: a mathematical modeling view.

The locomotor gait in limbed animals is defined by the left-right leg coordination and locomotor speed. Coordination between left and right neural activities in the spinal cord controlling left and right legs is provided by commissural interneurons (CINs). Several CIN types have been genetically identified, including the excitatory V3 and excitatory and inhibitory V0 types. Recent studies demonstrated that genetic elimination of all V0 CINs caused switching from a normal left-right alternating activity to a left-right synchronized "hopping" pattern. Furthermore, ablation of only the inhibitory V0 CINs (V0D subtype) resulted in a lack of left-right alternation at low locomotor frequencies and retaining this alternation at high frequencies, whereas selective ablation of the excitatory V0 neurons (V0V subtype) maintained the left-right alternation at low frequencies and switched to a hopping pattern at high frequencies. To analyze these findings, we developed a simplified mathematical model of neural circuits consisting of four pacemaker neurons representing left and right, flexor and extensor rhythm-generating centers interacting via commissural pathways representing V3, V0D, and V0V CINs. The locomotor frequency was controlled by a parameter defining the excitation of neurons and commissural pathways mimicking the effects of N-methyl-D-aspartate on locomotor frequency in isolated rodent spinal cord preparations. The model demonstrated a typical left-right alternating pattern under control conditions, switching to a hopping activity at any frequency after removing both V0 connections, a synchronized pattern at low frequencies with alternation at high frequencies after removing only V0D connections, and an alternating pattern at low frequencies with hopping at high frequencies after removing only V0V connections. We used bifurcation theory and fast-slow decomposition methods to analyze network behavior in the above regimes and transitions between them. The model reproduced, and suggested explanation for, a series of experimental phenomena and generated predictions available for experimental testing.