Abstract Objectives: To explain the high mortality of septic shock in children with cancer. Methods: A retrospective cohort from 2016 to 2020, of children aged 0 to 18 years, and septic shock. Results: The authors included 139 patients. Acute lymphocytic leukemia was the most frequent diagnosis (16.5%), and Gram-negative bacteria were the most frequent blood culture isolates (22.3%). There were 57 deaths in ICU (41%), 10 in the first 24 hours of shock (early death). A LASSO model with variables: neutropenia (coefficient 0.215), respiratory (0.81), hematological (1.41), and neurological (0.72) dysfunctions, age (-0.002) and solid tumor recurrence (0.34) generated AUC = 0.79 for the early death outcome. Survivors had significant differences in the PRISM-IV score (mean ± SD 10.9 ± 6.2 in the survivors, 14.1 ± 6.5 in the deceased, p = 0.004), and in the mean number of organ dysfunctions (3.2 ± 1.1 in the survivors, 3.8 ± 6.5 in the deceased, p < 0.001). A positive fluid balance in the first 24 hours of sepsis between 2% and 6% of body weight showed a reduction effect on the probability of death in ICU (hazard ratio 0.47, 95% CI 0.24–0.92, p = 0.027). The recurrence of any cancer was a predictor of in-hospital death, regardless of severity. Conclusions: Recurrence of any cancer is an important risk of sepsis-related death. A positive fluid balance between 20 and 60 mL/kg or 2% and 6% of body weight in the first 24 hours after the onset of sepsis is related to lower mortality.

JUSTIFICATIVA E OBJETIVOS: Determinar o grau de concordância e correlação entre amostras arteriais e as obtidas através de um cateter venoso umbilical, com relação ao pH, bicarbonato, excesso de base (BE) e lactato, em recém-nascidos prematuros e de termo, criticamente doentes. MÉTODO: Foram obtidas amostras para gasometria (0,5 - 1 mL), por punção de artéria radial, e, dentro do limite de 5 minutos, do cateter venoso umbilical. O método de Bland-Altman foi utilizado para demonstrar a concordância entre as medidas. Os limites de concordância foram definidos como a diferença média ± 2 DP. Para as correlações foi utilizado o método de Pearson. RESULTADOS: Cento e seis amostras (53 pares) de 53 pacientes foram analisadas para bicarbonato, pH e BE. Foi dosado lactato em 49 pares de amostras. Houve concordância em 94,3% dos pares de amostras para o pH, e este mesmo percentual foi observado para o bicarbonato. Para o excesso de base, a concordância foi de 96,2%, e de 91,8% para o lactato. As diferenças médias foram 0,03 unidade para o pH, -1,2 mmol/L para o bicarbonato, -0,24 mmol/L para o excesso de base e 0,33 mmol/L para o lactato. Os coeficientes de correlação de Pearson (r) foram 0,87 para o pH, 0,76 para o bicarbonato, 0,86 para o excesso de base e 0,95 para o lactato. CONCLUSÕES: Os valores venosos isolados não podem ser usados como equivalentes aos arteriais para a avaliação do estado ácido-básico em recém-nascidos. As amostras venosas poderiam ser usadas de forma serial, para monitorizar tendências ao longo do tempo.

BACKGROUND AND OBJECTIVES: Determine the extent of agreement and correlation between arterial samples and venous (obtained from a venous umbilical catheter), with respect to measurements of pH, bicarbonate, base excess and lactate, in critically ill term and premature newborns. METHODS: Arterial blood samples (0.5-1 mL) were obtained for gas analysis by radial artery puncture, and, within the limit of 5 minutes, samples were obtained from venous umbilical catheters. Bland-Altman plots were used to depict agreement between arterial and venous measurements. Limits of agreement were defined as the mean difference ± 2SD (Standard Deviation). Correlation was assessed by Pearson's method. RESULTS: A hundred and six samples (53 pairs) were taken from 53 patients for analysis of bicarbonate, pH and base excess. Lactate was analyzed in 49 pairs of samples. Differences were within the limits of agreement in 94.3% of pairs of samples for pH, and the same percentage was observed for bicarbonate. There was agreement in 96.2% of pairs for base excess, and in 91.8% for lactate. Mean differences were 0.03 units for pH, -1.2 mmol/L for bicarbonate, -0.24 mmol/L for base excess and 0.33 mmol/L for lactate. Pearson's correlation coefficients (r) were 0.87 for pH, 0.76 for bicarbonate, 0.86 for base excess and 0.95 for lactate. CONCLUSIONS: Although single venous values cannot be used as equivalent to arterial for assessing acid base status in newborns, venous blood samples can be used serially for monitoring trends over time.