A simple method to assess postoperative risk

Accuracy of six minute walk test, stair test and spirometry using maximal oxygen uptake as gold standard

PURPOSE: To assess the accuracy of the variables stair climbing time (SCt), stair climbing power (SCP), six-minute walk test distance (6MWT), and forced expiratory volume in 1 second (FEV1) using maximal oxygen uptake on exercise (VO2max) as the gold standard. METHODS: Tests were performed in 51 patients. FEV1 was measured by spirometry and 6MWT was performed in a flat 120-m corridor. Stair climbing test was performed on a 6-flight stairway to obtain SCt and SCP. VO2max was measured by ergospirometry, using the Balke protocol. Pearson's linear correlation and p values were calculated between VO2max and the other variables tested. For accuracy calculations, variable cutoff points were obtained through receiver operating characteristic (ROC) curves, dividing individuals into normal or unhealthy. Kappa statistic was used to calculate concordance. RESULTS: Accuracy was: SCt - 86%, 6MWT - 80%, SCP - 71%, FEV1(L) - 67%, FEV1(%) - 63%. SCt and 6MWT showed 93.5% sensitivity when combined in parallel, and 96.4% specificity in series. CONCLUSION: SCt presented the best accuracy. SCt and 6MWT combined showed nearly 100% sensitivity or specificity. Thus, these simple exercise tests should be more routinely used, especially when an ergospirometer is not available to measure VO2max.

Acurácia do teste de escada utilizando o consumo máximo de oxigênio como padrão-ouro

OBJETIVO: Determinar a acurácia dos atributos do teste de escada (TE) de altura definida utilizando como padrão-ouro o consumo máximo de oxigênio (VO2 máx). MÉTODOS: O TE foi realizado com incentivo, em escada (6 lances; 72 degraus; 12,16 m de altura total), em 51 pacientes. O 'tempo' de subida foi cronometrado e o 'trabalho' e a 'potência' calculados. O VO2 máx foi obtido por ergoespirometria, utilizando-se o protocolo de Balke. Foram calculados a correlação linear de Pearson (r) e os valores de p entre as variáveis do TE e o VO2 máx. Para o cálculo da acurácia, o ponto de corte do VO2 máx foi estabelecido em 25 mL/kg/min, estratificando os indivíduos em normais ou alterados. Os pontos de corte para os atributos do TE foram obtidos através da curva receiver operating characteristic. A estatística Kappa (k) foi utilizada para estudo da concordância. RESULTADOS: Obtiveram-se os seguintes valores para a variável 'tempo': ponto de corte = 40 s; x= 41 ± 15,5 s; r = -0,707; p < 0,005; especificidade = 89%; sensibilidade = 83%; acurácia = 86% e k = 0,724. Para a variável 'potência', obteve-se ponto de corte = 200 w; x= 222,3 ± 95,2 w; r = 0,515; p < 0,005; especificidade = 67%; sensibilidade = 75%; acurácia = 71% e k = 0,414. A correlação de 'trabalho' com o VO2 máx não foi significativa, sendo esse atributo descartado. CONCLUSÃO: Dos atributos testados do TE, tendo como padrão-ouro o VO2 máx, a variável 'tempo' foi a que apresentou a melhor acurácia.

Lung cancer screening by spiral CT. What is the optimal target population for screening trials?

The purpose of this document is to provide recommendations for the selection of the optimal target population for lung cancer screening trials with Spiral Computer Tomography based on an analysis of risk factors and high-risk populations. Our recommendations are to include current or ex-smokers (<5 years) with a smoking history of at least 30 years and an average consumption of at least 20 cigarettes a day. When these selection criteria are applied there is no need for a lower age cut-off. Elderly people can be included as long as their life expectancy is more than 10 years. Participants should be fit enough to undergo thoracic surgery. They may have a history of previous cancer, provided that the cancer has been curatively treated at least 5 years ago without evidence of relapse, except for breast cancer, melanoma and hypernephroma. People with an inability to lie flat, who are unable to hold their breath for 20 s, with a body weight above 140 kg, a chest CT scan within 1 year before enrolment or a previous pneumonectomy should not be invited. The inadequacy of the unit 'Pack-Years' (PY) to estimate the individual lung cancer risk is recognised, and future initiatives to develop an appropriate lung cancer risk model are encouraged.