Anatomic accuracy, physiologic characteristics, and fidelity of very low birth weight infant airway simulators.

BACKGROUND: Medical simulation training requires realistic simulators with high fidelity. This prospective multi-center study investigated anatomic precision, physiologic characteristics, and fidelity of four commercially available very low birth weight infant simulators. METHODS: We measured airway angles and distances in the simulators Premature AirwayPaul (SIMCharacters), Premature Anne (Laerdal Medical), Premie HAL S2209 (Gaumard), and Preterm Baby (Lifecast Body Simulation) using computer tomography and compared these to human cadavers of premature stillbirths. The simulators' physiologic characteristics were tested, and highly experienced experts rated their physical and functional fidelity. RESULTS: The airway angles corresponded to those of the reference cadavers in three simulators. The nasal inlet to glottis distance and the mouth aperture to glottis distance were only accurate in one simulator. All simulators had airway resistances up to 20 times higher and compliances up to 19 times lower than published reference values. Fifty-six highly experienced experts gave three simulators (Premature AirwayPaul: 5.1 ± 1.0, Premature Anne 4.9 ± 1.1, Preterm Baby 5.0 ± 1.0) good overall ratings and one simulator (Premie HAL S2209: 2.8 ± 1.0) an unfavorable rating. CONCLUSION: The simulator physiology deviated significantly from preterm infants' reference values concerning resistance and compliance, potentially promoting a wrong ventilation technique. IMPACT: Very low birth weight infant simulators showed physiological properties far deviating from corresponding patient reference values. Only ventilation with very high peak pressure achieved tidal volumes in the simulators, as aimed at in very low birth weight infants, potentially promoting a wrong ventilation technique. Compared to very low birth weight infant cadavers, most tested simulators accurately reproduced the anatomic angular relationships, but their airway dimensions were relatively too large for the represented body. The more professional experience the experts had, the lower they rated the very low birth weight infant simulators.

The value of specific IgE to peanut and its component Ara h 2 in the diagnosis of peanut allergy.

BACKGROUND: To avoid unnecessary oral food challenges, which are time consuming, stressful, and risky, improved in vitro diagnostic methods for food allergy such as component resolved diagnostics are still under investigation. OBJECTIVE: To investigate the role of whole peanut- and peanut-component (Ara h 1, Ara h 2, Ara h 3, Ara h 6 and Ara h 8)-specific IgE levels in the diagnostic procedure of peanut allergy as well as the diagnostic properties of peanut-specific IgG and IgG4. METHODS: Sixty-one children underwent oral peanut challenge tests for diagnostic purposes irrespective of their peanut-specific IgE levels. Peanut-specific serum IgE, IgG, and IgG4 levels were determined by ImmunoCAP FEIA and specific IgE against individual peanut proteins by Immuno Solid-phase Allergen Chip. RESULTS: Thirty-four of 61 patients (56%) had a peanut allergy. No significant difference was observed for peanut-specific IgG or peanut-specific IgG4 levels between patients who were allergic and tolerant patients, whereas peanut-specific IgE was significant higher in patients who were allergic than in tolerant patients (P < .005). Twenty-five of 61 children had peanut-specific IgE above a previously proposed cutoff level of 15 kUA/L; however, 7 of these 25 children (28%) were clinically tolerant. Ara h 2-specific IgE was significantly lower in tolerant than in patients with allergies (P < .0001). Interestingly, 94% of the patients with peanut allergies showed IgE-binding to Ara h 2. Unfortunately, 26% of the sensitized but tolerant patients have shown IgE binding to Ara h 2 too. CONCLUSIONS: Neither the level of specific IgE to peanut nor to Ara h 2 was able to clearly distinguish patients with clinical relevant peanut allergy from those who were clinical tolerant in our population. As expected, peanut-specific IgG and IgG4 did not improve the diagnostic procedure.