[Reference values for the 6-minutes walking test in healthy Chilean children]. / Valores de referencia del test de marcha de seis minutos en niños sanos.

BACKGROUND: The 6-minutes walking test (6WT) is the ideal submaximal test for the evaluation and follow-up of patients with chronic respiratory diseases. There are no reference values (RV) for Chilean children using the American Thoracic Society guidelines. AIM: To generate 6WT reference values for Chilean children aged 6 to 14 years. MATERIAL AND METHODS: 6MW was evaluated in 192 healthy children (100 women) aged between 6 and 14 years. The test was carried out in a 30 m long indoor flat surface. Children also answered a survey about health problems and their weight and height were recorded. RESULTS: The distance walked by women and men was 596.5 ± 57 and 625 ± 59.7 m respectively (p < 0.05). There was a significant correlation between the distance walked and height (r = 0.58), age (r = 0.56), weight (r = 0.54) and reserve heart rate (r = 0.21). CONCLUSIONS: These results can be used as reference values for the 6WT in Chilean children aged 6 to 14 years. They are similar to those reported abroad.

Early rise in central venous pressure during a spontaneous breathing trial: A promising test to identify patients at high risk of weaning failure?

BACKGROUND: The spontaneous breathing trial (SBT) assesses the risk of weaning failure by evaluating some physiological responses to the massive venous return increase imposed by discontinuing positive pressure ventilation. This trial can be very demanding for some critically ill patients, inducing excessive physical and cardiovascular stress, including muscle fatigue, heart ischemia and eventually cardiac dysfunction. Extubation failure with emergency reintubation is a serious adverse consequence of a failed weaning process. Some data suggest that as many as 50% of patients that fail weaning do so because of cardiac dysfunction. Unfortunately, monitoring cardiovascular function at the time of the SBT is complex. The aim of our study was to explore if central venous pressure (CVP) changes were related to weaning failure after starting an SBT. We hypothesized that an early rise on CVP could signal a cardiac failure when handling a massive increase on venous return following a discontinuation of positive pressure ventilation. This CVP rise could identify a subset of patients at high risk for extubation failure. METHODS: Two-hundred and four mechanically ventilated patients in whom an SBT was decided were subjected to a monitoring protocol that included blinded assessment of CVP at baseline, and at 2 minutes after starting the trial (CVP-test). Weaning failure was defined as reintubation within 48-hours following extubation. Comparisons between two parametric or non-parametric variables were performed with student T test or Mann Whitney U test, respectively. A logistic multivariate regression was performed to determine the predictive value on extubation failure of usual clinical variables and CVP at 2-min after starting the SBT. RESULTS: One-hundred and sixty-five patients were extubated after the SBT, 11 of whom were reintubated within 48h. Absolute CVP values at 2-minutes, and the change from baseline (dCVP) were significantly higher in patients with extubation failure as compared to those successfully weaned. dCVP was an early predictor for reintubation (OR: 1.70 [1.31,2.19], p<0.001). CONCLUSIONS: An early rise in CVP after starting an SBT was associated with an increased risk of extubation failure. This might represent a warning signal not captured by usual SBT monitoring and could have relevant clinical implications.

Valores de referencia del test de marcha de seis minutos en niños sanos / Reference values for the 6-minutes walking test in healthy Chilean children

Background: The 6-minutes walking test (6WT) is the ideal submaximal test for the evaluation and follow-up of patients with chronic respiratory diseases. There are no reference values (RV) for Chilean children using the American Thoracic Society guidelines. Aim: To generate 6WT reference values for Chilean children aged 6 to 14 years. Material and Methods: 6MW was evaluated in 192 healthy children (100 women) aged between 6 and 14 years. The test was carried out in a 30 m long indoor flat surface. Children also answered a survey about health problems and their weight and height were recorded. Results: The distance walked by women and men was 596.5 ± 57 and 625 ± 59.7 m respectively (p < 0.05). There was a significant correlation between the distance walked and height (r = 0.58), age (r = 0.56), weight (r = 0.54) and reserve heart rate (r = 0.21). Conclusions: These results can be used as reference values for the 6WT in Chilean children aged 6 to 14 years. They are similar to those reported abroad.

Multiplex PCR for diagnosis of enteric infections associated with diarrheagenic Escherichia coli.

A multiplex PCR for detection of three categories of diarrheagenic Escherichia coli was developed. With this method, enterohemorrhagic E. coli, enteropathogenic E. coli, and enterotoxigenic E. coli were identified in fecal samples from patients with hemorrhagic colitis, watery diarrhea, or hemolytic-uremic syndrome and from food-borne outbreaks.