ABSTRACT
Background: Advances in critical care have increased survival chances and the demand for a scientific approach to outcome prediction. The present study aimed to investigate the associations of clinical information, demographic and laboratory data with mortality; and to elaborate and validate a regression equation for mortality prediction in a medical intensive care unit (ICU). Methods: This study included 202 patients and took place in a medical ICU at the Botucatu Medical School Hospital, Brazil. In Phase 1, 123 patients admitted to ICU between September 2003 and October 2004 was retrospectively analyzed and allowed equation elaboration. In Phase 2, the mortality equation was prospectively applied in 79 patients consecutively admitted to ICU between August and December 2006. Results: Among Phase 1 patients, 55% were males and mean age was 58±19 years. Mortality rate was 29%. Multivariate analysis revealed that shock (p=0.002) and hypoalbuminemia (p=0.024) were associated with higher mortality rate. When regression equation was applied in Phase 2 patients, higher equation values were shown for nonsurvivors (0.512; -1.008 -0.512) than for survivors (-1.008; -1.290 -1.008) (p=0.03). The equation also had good precision, 1.8% (IC95%; 1.1-4.7), and low bias, -3.1% (IC95%; -27.1 -20.8). Areas under the receiver operating characteristic (ROC) curve showed no statistical differences between APACHE II (0.75±0.06) and the equation (0.66±0.07) (p=0.27). Conclusions: Our data suggest that a simple and accurate prognostic equation can be used to predict ICU mortality.
ABSTRACT
BACKGROUND AND OBJECTIVE: The present study aimed to evaluate the utility of variables that represent unmeasured anions (anion gap, anion gap corrected for albumin, anion gap corrected for albumin and lactate, base excess and modified base excess) to predict mortality in medical intensive care unit patients. METHODS: This prospective study included 156 con secutive patients admitted to a medical intensive care unit in a Medical school hospital between August 2006 and June 2007. Serum levels of potassium, sodium, chloride, C-reactive protein, albumin, and lactate were measured. Variables that re- present unmeasured anions and APACHE II score were calcula- ted. RESULTS: Among the studied patients, 60.9% were male, and mean age was 59.2±17.2 years. Mortality rate was 31.4%. Spearman?s test showed correlation among unmeasured anions and lactate. Comparison between survivors and non-survivors showed differences in length of intensive care unit stay, APACHE II score, albumin, C-reactive protein, lactate, anion gap corrected for albumin, base excess, and modified base excess. Anion gap corrected for albumin, base excess, and modified base excess are predictors of medical intensive care unit mortality; however, theirs areas under the ROC curves are smaller than APACHE II score and C-reactive protein. CONCLUSION: Variables that estimate unmeasured anions, such as anion gap corrected for albumin, base excess, and modified base excess, can be used to predict mortality in medical intensive care unit patients.(AU)
JUSTIFICATIVA E OBJETIVO: O presente estudo teve como objetivo avaliar a utilidade de variáveis que representam ânions não mensuráveis (ânion gap, ânion gap corrigido para a al- bumina, ânion gap corrigido para a albumina e lactato, excesso de base e excesso de base modificado) para prever a mortalidade em pacientes de unidade de terapia intensiva. MÉTODOS: Foram incluídos 156 pacientes consecutivos admitidos na unidade de terapia intensiva em um hospital escola de Medicina entre agosto de 2006 e junho de 2007. Os níveis séricos de potássio, sódio, cloreto, proteina C-reativa, albumina e lactato fo ram medidos. Foram calculadas variáveis que representaram os ânions não mensuráveis e APACHE II. RESULTADOS: Entre os pacientes estudados, 60,9% eram do sexo masculino, e a idade média foi de 59,2±17,2 anos. A taxa de mortalidade foi de 31,4%. O teste de Spearman mostrou correlação entre ânions não mensuráveis e lactato. A comparação entre sobreviventes e não sobreviventes mostrou diferenças no tempo de permanência na unidade de terapia intensiva, APACHE II, albumina, proteína C-reativa, lactato, ânion gap corrigido para a albumina, excesso de base e excesso de base modificado. Ânion gap corrigido para a albumina, excesso de base e excesso de base modificado foram preditores de mortalidade na unidade de terapia intensiva médica, mas as áreas sob as curvas ROC foram menores do que o escore APACHE II e a proteína C-reativa. CONCLUSÃO: Variáveis que estimam ânions não mensuráveis, como o ânion gap corrigido para a albumina, o excesso de base e o excesso de base modificado, podem ser usados para prever a mortalidade em pacientes em unidade de terapia intensiva clínica.(AU)