Chest
Laboratory and Animal InvestigationsTransbronchial Biopsy in the Presence of Profound Elevation of the International Normalized Ratio
Section snippets
Study Design
The Yucatan mini-swine (Sus scrofa) was selected for the study based on its chest shape, its size, and the similarity of its pulmonary vascular system to that of humans. Previous anticoagulation studies using warfarin have been used in this animal model, and the swine's coagulation system has been demonstrated to be similar to that of humans.
The study was planned as a two-stage crossover study with animals serving as their own controls. In the first stage, the goal was to determine an INR level
Results
Eighteen animals were enrolled in the study. Despite extreme elevations in INR levels (> 7) in 11 animals, no animals developed a hemorrhagic complication due to TBBx (Table 3). Stage 1 of the study was discontinued when no significant hemorrhaging was noted. Stage 2 of the study was not performed due to the failure to identify an INR level that indicated a significant risk of hemorrhage following TBBx. Three animals had an INR between 5 and 6. Four animals died during the study. The death of
Discussion
The Yucatan mini-swine was chosen for this study for the following reasons: (1) the size of the animal allowed intubation with a 7.5-mm endotracheal tube that would accommodate a bronchoscope with a channel diameter sufficient to allow the use of 2.2-mm biopsy forceps; (2) the shape and size of the animal approximated that of a small adult patient; (3) the previous use of this animal in cardiac stent and anticoagulation studies; and (4) similarities between swine and human coagulation systems.12
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Cited by (24)
Flexible Bronchoscopy
2018, Clinics in Chest MedicineCitation Excerpt :Although little evidence exists regarding management safety of bronchoscopy in the setting of anticoagulants or intrinsic coagulopathy, this also must be considered a relative contraindication for bronchoscopy biopsy. In a swine model evaluating rates of bleeding after TBLB with or without warfarin-induced coagulopathy, no difference in bleeding was identified between controls and animals on anticoagulation with an International Normalized Ratio of up to 10.125 These findings should be considered with caution, however, because similar results were seen in swine after the administration of clopidogrel, which did not correlate with findings on subsequent human studies.121
Good practices of diagnostic flexible bronchoscopy
2007, Revue des Maladies RespiratoiresDentoalveolar Procedures for the Anticoagulated Patient: Literature Recommendations Versus Current Practice
2007, Journal of Oral and Maxillofacial SurgeryCitation Excerpt :An INR range from 2.5 to either 3.5 or 4.0 is advocated for mechanical heart valves by American Heart Association/American College of Cardiology48,49 and European Society of Cardiology/British Committee for Standards in Hematology50-54 recommendations, respectively. An INR above this range may increase the patient’s risk for a spontaneous or surgically induced bleeding episode,90 while an INR below the desired therapeutic level increases the risk for thromboembolism19,91 and ischemic cerebrovascular event.21,92 A recent investigation at our institution monitored surgical complications in pretransplant liver failure patients.
Effect of routine clopidogrel use on bleeding complications after transbronchial biopsy in humans
2006, ChestCitation Excerpt :Our results also question the validity of the assumption that results of animal experiments in this area can be extrapolated to humans. For example, a study by Brickey and Lawlor16 is frequently quoted as evidence that warfarin-induced international normalized ratio prolongation is not associated with bleeding complications during transbronchial biopsies done in pigs. This trial was also performed in animals, and its validity has never been tested in humans.
Effect of clopidogrel with and without aspirin on bleeding following transbronchial lung biopsy
2005, ChestCitation Excerpt :With the exception of the right upper lobe bronchus arising from the trachea, the airways pigs have similar tracheobronchial trees, as well as mucosal and tissue characteristics.19 Pig models have been used previously in bronchoscopy training, research on airway stenosis, malacia, airway stents, and, most relevant to our study, TBLB experiments.19–23 We selected the Yorkshire pig species due to the proximity of the average weight of the animals to that of adult humans.
For editorial comment see page 1492.
Financial support was given through the office of the United State Air Force Surgeon General and was distributed through the Clinical Investigation Facility at Wilford Hall Medical Center.