Inhalational use of antithrombotics in humans: Review of the literature.

INTRODUCTION: Off label use of anticoagulants is common. The association between fibrin deposition in the lungs and primary lung disease, injury or prematurity affords a strong theoretical basis for the potential benefit of antithrombotic therapies administered directly to the lung tissue. This review offers a critical appraisal of current evidence related to the inhalational administration of antithrombotic therapy in humans. MATERIALS AND METHODS: An interrogation of 2 databases across a 13 year period of time was undertaken using key words selected a priori. Identified publications were categorized according to the following themes: 1. Inhaled antithrombotic therapy in healthy subjects 2. Inhaled antithrombotic therapy for vascular thromboprophylaxis 3. Inhaled antithrombotic therapy in smoke inhalation and lung injury 4. Inhaled antithrombotic therapy in asthma or allergy 5. Inhaled antithrombotic therapy for plastic bronchitis post-Fontan surgery 6. Inhaled antithrombotic therapy for other indications. RESULTS: 33 articles were identified consistent with the inclusion criteria developed for this review. Unfractionated heparin, LMWH, activated protein C and thrombolytic agents have been administered via the respiratory track, with asthma and smoke inhalation/lung injury being the most frequently investigated clinical scenarios described. All studies reported had significant methodological limitations. CONCLUSIONS: The safety and clinical utility of inhaled antithrombotic therapies have not been adequately investigated to support the generation of any firm evidence. This review highlights where inhaled antithrombotic therapies have shown promise and importantly, the further research required to confirm mechanism of action and a definitive risk: benefit profile.

Quantitative MR imaging of carpal tunnel syndrome.

OBJECTIVE: Previous MR imaging studies have produced evidence of changes to structures within the wrist believed to be associated with carpal tunnel syndrome. In an attempt to resolve the conflicting and inconclusive results of these studies, we report here the results of an MR imaging study at a field strength of 3.0 T, which is higher than that previously reported. SUBJECTS AND METHODS: Patients with carpal tunnel syndrome and control groups of asymptomatic subjects were studied using MR imaging. We evaluated electrophysiologically the median nerve function of the affected wrists of all patients. A gradient-recalled echo pulse sequence was used to study 13 3-mm-thick slices within the wrist of each patient or asymptomatic subject. Spatial resolution was approximately 0.3 x 0.3 mm2. The median nerve and other structures associated with the carpal tunnel, which were clearly shown on the MR images, were analyzed to yield structural data. RESULTS: Analysis revealed that the cross-sectional area of the nerve within and proximal to the carpal tunnel was approximately 50% larger in patients with carpal tunnel syndrome than in asymptomatic subjects. We found no significant difference in the area of the nerve within the carpal tunnel compartment compared with the area of the nerve proximal to the carpal tunnel either in patients or in asymptomatic subjects. Also, flattening of the nerve on entering the carpal tunnel was not significantly different in patients than in asymptomatic subjects. In patients an increase in the palmar bowing of the flexor retinaculum was found only at the level of the hamate compared with that found in asymptomatic subjects. The cross-sectional area of the carpal tunnel was of a similar size in patients and in asymptomatic subjects. Comparison of electrodiagnostic results indicated no correlations between the MR parameters and electrophysiologic dysfunction of the median nerve for patients. CONCLUSION: The only statistically significant differences found between patients with carpal tunnel syndrome and asymptomatic subjects were that the median nerve was approximately 50% larger within and proximal to the carpal tunnel in patients with carpal tunnel syndrome and palmar bowing of the flexor retinaculum occurred in patients only at the level of the hamate.