The role of serum lactate in post-cardiac arrest syndrome

Cardiopulmonary arrest is a medical emergency with significant mortality. The success of resuscitation led to the emergence of post-cardiac arrest syndrome (PCAS), which originates from ischemia-reperfusion injury and its consequent increase in serum lactate. Despite the robust evidence correlating hyperlactatemia as a prognostic marker in critically ill patients, there is insufficient evidence about the role of serum lactate in the outcome of PCAS. Thus, the purpose of this review is to check the current evidence on the role of lactate in predicting mortality in PCAS.Keywords: Cardiac arrest; cardiopulmonary resuscitation; lactic acid

Energy expenditure in mechanical ventilation: is there an agreement between the Ireton-Jones equation and indirect calorimetry?

OBJECTIVE: Assess the agreement between the energy expenditure measured by indirect calorimetry and that estimated by the Ireton-Jones formula of critically ill patients under assisted mechanical ventilation. METHODS: Participated in the study individuals able to interrupt ventilation support, admitted at the center of intensive care of the Hospital de Clínicas de Porto Alegre - RS, between August 2006 and January 2007. Energy expenditure was measured by indirect calorimetry using a specific monitor, as well as estimated by the Ireton-Jones formula. Values found were analyzed using the Student's t test and the Bland and Altman method and expressed in mean, ± standard deviation with a significance level of p<0.05. RESULTS: The study included forty patients with a mean age of 56±16 years and APACHE II score of 23±8. Energy expenditure measured by indirect calorimetry was of 1558±304kcal/24h, while that estimated by Ireton-Jones was of 1689±246kcal/24h. There was a significant statistical difference between means of energy expenditure measured and estimated of the same individual (p<0.004). The agreement thresholds between indirect calorimetry and the Ireton-Jones equation were of -680.51 to 417.81 kcal. CONCLUSION: Energy expenditure estimated by the Ireton-Jones formula did not present good agreement with that measured by indirect calorimetry, however, considering aspects related to availability of the equipment, this equation may be useful in the nutritional planning for critically ill patients.OBJETIVO: Avaliar a concordância entre o gasto energético mensurado pela calorimetria indireta e o estimado pela fórmula de Ireton-Jones de pacientes críticos em ventilação mecânica assistida. MÉTODOS: Participaram do estudo indivíduos aptos a interromper o suporte ventilatório, internados entre agosto de 2006 e janeiro de 2007, no centro de terapia intensiva do Hospital de Clínicas de Porto Alegre - RS. O gasto energético foi mensurado pela calorimetria indireta usando monitor específico, assim como calculado pela fórmula de Ireton-Jones. Os valores encontrados foram analisados por meio do teste t de Student e pelo método de Bland and Altman, e expressos pela média ± desvio padrão, com nível de significância p<0,05. RESULTADOS: Foram incluídos no estudo quarenta pacientes, com idade média de 56±16 anos e índice APACHE II 23±8. O gasto energético mensurado pela calorimetria indireta foi de 1558±304kcal/24h, enquanto o estimado por Ireton-Jones foi de 1689±246kcal/24h. Houve diferença estatisticamente significativa entre as médias do gasto energético mensurado e estimado para o mesmo indivíduo (p<0,004). Os limites de concordância entre a calorimetria indireta e a equação de Ireton-Jones foram de -680,51 a 417,81 kcal. CONCLUSÃO: O gasto energético estimado pela fórmula de Ireton-Jones não apresentou boa concordância com o medido pela calorimetria indireta, entretanto, considerando aspectos relacionados à disponibilidade do aparelho, esta equação pode auxiliar no planejamento nutricional dos pacientes críticos.12913

Mechanical ventilation in patients in the intensive care unit of a general university hospital in southern Brazil: an epidemiological study

OBJECTIVES: To determine the characteristics, the frequency and the mortality rates of patients needing mechanical ventilation and to identify the risk factors associated with mortality in the intensive care unit (ICU) of a general university hospital in southern Brazil. METHOD: Prospective cohort study in patients admitted to the ICU who needed mechanical ventilation for at least 24 hours between March 2004 and April 2007. RESULTS: A total of 1,115 patients admitted to the ICU needed mechanical ventilation. The mortality rate was 51%. The mean age (± standard deviation) was 57±18 years, and the mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 22.6±8.3. The variables independently associated with mortality were (i) conditions present at the beginning of mechanical ventilation, age (hazard ratio: 1.01;