Avaliação de Testes Diagnósticos

Problema

Leia atentamente o seguinte "Abstract":

Does this patient have abdominal aortic aneurysm?
Lederle FA, Simel DL

JAMA 1999 Jan 6;281(1):77-82
Department of Medicine, Minneapolis Veterans Affairs Medical Center, University of Minnesota, 55417, USA. vhaminlederf@med.va.gov

In the physical examination of abdominal aortic aneurysm (AAA), the only maneuver of demonstrated value is abdominal palpation to detect abnormal widening of the aortic pulsation. Palpation of AAA appears to be safe and has not been reported to precipitate rupture. The best evidence on the accuracy of abdominal palpation comes from 15 studies of patients not previously known to have AAA who were screened with both abdominal palpation and ultrasound. When results from these studies are pooled, the sensitivity of abdominal palpation increases significantly with AAA diameter (P<.001), ranging from 29% for AAAs of 3.0 to 3.9 cm to 50% for AAAs of 4.0 to 4.9 cm and 76% for AAAs of 5.0 cm or greater. The positive predictive value of palpation for AAA of 3.0 cm or greater in these studies was 43%. Limited data suggest that abdominal obesity decreases the sensitivity of palpation. Abdominal palpation specifically directed at measuring aortic width has moderate sensitivity for detecting an AAA that would be large enough to be referred for surgery but cannot be relied on to exclude AAA, especially if rupture is a possibility.

 

Partindo do pressuposto de que os resultados deste trabalho são válidos e podem ser aplicados à população de doentes que se apresentam no Serviço de Urgência do HSJ, responda às seguintes questões:

    1. Qual a probabilidade de um doente que aparece no SU do HSJ com um aneurisma da aorta abdominal de 3.5 cm ter uma palpação abdominal positiva?
    2. Qual a probabilidade de um doente que aparece no SU do HSJ com um aneurisma da aorta abdominal de 4.5 cm ter uma palpação abdominal positiva?
    3. Qual a probabilidade de um doente que aparece no SU do HSJ com um aneurisma da aorta abdominal de 5.5 cm ter uma palpação abdominal positiva?
    4. Qual a probabilidade de um doente que aparece no SU do HSJ e tem uma palpação abdominal positiva ter um aneurisma da aorta abdominal maior que 3 cm?