Transbronchial biopsy in the presence of profound elevation of the international normalized ratio.
OBJECTIVE
To identify a level of coagulopathy, reported as the international normalized ratio (INR), that predicts hemorrhage following transbronchial forceps biopsy (TBBx) in an animal model.


METHODS
Crossover blinded study using Yucatan mini-swine (Sus scrofa).


METHODS
Tertiary medical center with a dedicated animal research facility.


METHODS
A two-stage study. In stage 1, flexible fiberoptic bronchoscopy with TBBx was performed to establish the amount of bleeding in animals with normal coagulation systems. Animals then were administered escalating dosages of warfarin to obtain one of several increased INR levels. The endpoint of stage 1 was defined as the INR that resulted in a blood loss of > or = 100 mL in > or = 50% of the study animals. In stage 2, all the animals were to be anticoagulated to the INR level determined in stage 1. Topical and systemic measures would then be administered in an attempt to decrease postprocedure hemorrhage, and the results were recorded.


RESULTS
Eighteen animals were enrolled in the study. Despite INR levels > 10, no animals developed a hemorrhagic complication of the transbronchial forceps biopsy (TBBx). Eleven animals had INRs > 7. Four animal deaths were recorded, with three animal deaths attributed to nonpulmonary hemorrhage, each due to a ruptured ovarian cyst. One death was anesthesia related. Stage 2 of the study was not performed due to the extreme INR levels reached in the animals during stage 1 and to the lack of a procedure-related complication.


CONCLUSIONS
Our study suggests that INR elevation does not correlate with an increased risk of bleeding following TBBx in this animal model.
Brickey
D A
DA
Pulmonary/Critical Care Medicine Department Wilford Hall Medical Center, Lackland Air Force Base, TX, USA. david.brickey2@nellis.af.mil
Lawlor
D P
DP
D000818:Animals; D001706:Biopsy / Q000009:adverse effects*; D001778:Blood Coagulation Disorders / Q000097:blood*; D001999:Bronchoscopy; D018592:Cross-Over Studies; D004195:Disease Models, Animal; D005336:Fiber Optic Technology; D006469:Hemoptysis / Q000097:blood / Q000209:etiology; D019934:International Normalized Ratio; D012307:Risk Factors; D013552:Swine; D013556:Swine, Miniature