RESUMEN
Purpose: In chronic obstructive pulmonary disease (COPD) some patients develop paradoxical inspiratory rib motion, which is termed Hoover's sign. Our objective was to determine whether Hoover's sign is associated with a difference in the maximal expiratory pressure (MEP), the maximal inspiratory pressure (MIP), the MEP/MIP ratio, and other features on pulmonary function tests (PFTs). Methods: This observational prospective single-center cohort study enrolled patients with an established diagnosis of COPD with Global initiative for chronic Obstructive Lung Disease (GOLD) stage 3 (severe) and 4 (very severe) based on PFTs. Respiratory pressure measurements were also collected. Patients were examined for the presence or absence of Hoover's sign on physical examination by 2 internal medicine resident physicians trained in examining for Hoover's sign by a pulmonologist. Results: A total of 71 patients were examined for the presence of Hoover's sign. Hoover's sign was present in 49.3% of patients. Observer agreement (k statistic) was 0.8 for Hoover's sign. Median MEP/MIP was significantly greater in patients with Hoover's sign than those without Hoover's sign (1.88 versus 1.16, p<0.001). Patients with Hoover's sign also had a significantly lower MIP (39.0 versus 58.0, p<0.001) and higher residual volume (RV) to total lung capacity (TLC) ratio indicating a higher degree of air trapping (65 versus 59.5, p<0.014). Conclusion: The presence of Hoover's sign in patients with COPD is associated with a higher MEP/MIP ratio. This suggests respiratory pressure measurements can predict diaphragm dysfunction in patients with GOLD stage 3 and 4 COPD. Patients with Hoover's sign were also found to have a lower MIP and more air trapping.
RESUMEN
CONTEXT: Graduates of colleges of osteopathic medicine (COMs) frequently apply to residency training programs accredited by the Accreditation Council for Graduate Medical Education. However, students who have taken the Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) rather than the United States Medical Licensing Examination (USMLE) may encounter a selection bias when applying to allopathic residency programs. OBJECTIVE: To evaluate the correlation between scores on COMLEX-USA and USMLE by COM students who took both examinations. METHODS: Scores were analyzed from a cohort of COM students who took COMLEX-USA Level 1 and USMLE Step 1 and a cohort of students who, during the same time, took COMLEX-USA Level 2 and USMLE Step 2. RESULTS: At the Kirksville (Mo) College of Osteopathic Medicine of A.T. Still University of Health Sciences, 155 students took both COMLEX-USA Level 1 and USMLE Step 1 and another cohort of 56 students took COMLEX-USA Level 2 and USMLE Step 2. The Pearson product moment correlation of the scores from COMLEX-USA Level 1 and USMLE Step 1 was 0.83 (P<.001) and for COMLEX-USA Level 2 and USMLE Step 2 was 0.70 (P<.001). Scores on USMLE are predicted by the corresponding COMLEX-USA scores using the equations USMLE Step 1 = 67.97 + 0.24 x COMLEX-USA Level 1 (R(2)=0.68); and USMLE Step 2 = 102.2 + 0.18 x COMLEX-USA Level 2 (R(2)=0.46). CONCLUSION: A method of estimating USMLE scores from COMLEX-USA scores is provided for residency directors of institutions accredited by the Accreditation Council for Graduate Medical Education for the evaluation of COM applicants.