Bronchial allergen challenge using the Medicaid dosimeter.

BACKGROUND: Bronchial allergen provocations are well established in asthma research. We evaluated the reproducibility of single-concentration, single-step allergen challenges in volunteers with grass pollen allergy. METHODS: Forty-seven subjects underwent bronchial challenges using the aerosol provocation system nebulizer (Medicaid Sidestream) with incremental doses of grass pollen to define the individual allergen dose that causes a 20% drop in FEV(1) (PD(20)FEV(1)). In 39 subjects this procedure was followed by single-step challenges. Early and late asthmatic responses were monitored, and increases in exhaled nitric oxide were measured before and 24 h after single-step challenges. RESULTS: After the first single-step challenge, the maximum drop in FEV(1) was 21.3% ± 8.0. A comparison of the drop in FEV(1) to the initial incremental challenge (29.7% ± 7.5) revealed an intraclass correlation of -0.30 (p < 0.05). In the second single-step challenge, the mean drop in FEV(1) was 20.9% ± 7.2. Compared with the first single-step challenge, the intraclass correlation was 0.37 (p < 0.05) and the 95% limits of agreement according to Bland and Altman were -17.5 to 18.1%. The increases in exhaled nitric oxide revealed substantial agreement in repeated single-step challenges (26.8 ppb ± 27.8 and 21.8 ppb ± 21.9, ICC 0.62, p < 0.001). CONCLUSIONS: The use of aerosol provocation system to calculate the PD(20)FEV(1) allergen is a timesaving procedure and is less prone to errors because only one dilution of the allergen is used. The repeatability in well-defined subjects is excellent to study the mechanisms of allergen-induced airway inflammation and the development of new treatments for allergic diseases.

Methacholine challenge--comparison of an ATS protocol to a new rapid single concentration technique.

Bronchial methacholine challenge is well established in asthma diagnostics and research. ATS guidelines propose a five step standard dosimeter (SDM) protocol with incremental concentrations of methacholine to calculate the concentration causing a 20% drop in FEV(1) in an individual (PC(20)FEV(1)). In contrast, the aerosol provocation system (APS) by Viasys automatically determines the administered dose of methacholine by measuring the effective nebulisation time and referring it to drug concentration and nebuliser power. Therefore, it offers a feasible and less time-consuming provocation procedure by applying incremental doses (PD(20)) of methacholine using a single concentration (16mg/mL methacholine, APS-SC). In this study we compared these two methods in 52 young adults (25+/-5.8 years). Following a screening visit, subjects were randomly assigned to undergo either SDM or APS-SC followed by the other method within 1 week. A close correlation between concentration and dosage causing a 20% fall of FEV(1) was found (r=0.69, p<0.001). Using the ATS categorisation of bronchial responsiveness we interpreted the results of the APS-SC method as follows: PD(20) methacholine<0.3mg as "moderate to severe BHR", 0.3 - 0.6mg as "mild BHR", 0.6 - 1.0mg as "borderline BHR", and>1.0mg as "normal bronchial response". We conclude that the five-step APS-SC is a suitable method, providing reliable results. In clinical practice the APS-SC is a timesaving procedure and less prone to errors since only one dilution of methacholine is necessary compared to the SDM.

[Direct posterior approach for the treatment of posteromedial tibial head fractures]. / Die Osteosynthese posteromedialer Tibiakopffrakturen über einen direkten dorsalen Zugang.

OBJECTIVE: Direct posterior approach requiring minimal soft-tissue dissection for the treatment of posteromedial tibial head fractures. INDICATIONS: Posteromedial fractures of the proximal tibia. Bicondylar tibial plateau fractures involving the posteromedial aspect of the tibial plateau. The approach can be extended for exposure of the posterolateral plateau. CONTRAINDICATIONS: Local soft-tissue problems. SURGICAL TECHNIQUE: Direct posterior approach, mobilization and retraction of the medial head of gastrocnemius muscle. The fracture can be visualized by partial subperiosteal detachment of the popliteal muscle, whereas the medial head of gastrocnemius muscle and the semimembranosus muscle are preserved. Simplified reduction of the posteromedial fragment by extension of the knee and axial traction. Stabilization with lag screws and placement of a buttress plate (i.e., radial LCP T-plate or 3.5-mm LC plate). POSTOPERATIVE MANAGEMENT: Partial weight bearing with 15-20 kg for 6 weeks, unlimited range of motion. RESULTS: From 2001 to 2007, twelve patients (nine female, three male) with "medial split fractures" were treated via the direct posterior approach. Four patients had isolated "medial split fractures", seven patients bicondylar fractures of the tibial plateau, and one patient a four-part fracture. Six of our patients had acute injuries which were primarily treated at the authors' institution. The other six patients presented with malunited fractures or insufficient internal fixation (average 8.4 weeks, 3.5-24 weeks old). In all cases the fracture could be addressed by the described posterior approach. Sufficient reposition and restoration of anatomy could be achieved in all patients.