[Regional cerebral oxygen saturation as a marker of hemodynamic state following cardiac surgery]. / Saturación cerebral de oxígeno como marcador hemodinámico en la cirugía cardíaca.

INTRODUCTION: Regional cerebral oxygen saturation (rSO2) is a measure of the general state of perfusion and oxygenation. We aim to analyze the relationship between this and various hemodynamic and respiratory parameters. PATIENTS AND METHODS: Forty-three patients, operated on between October 2011 and July 2012, were included in this prospective observational descriptive study. The following parameters were measured: mean arterial pressure, both arterial and central venous oxygen saturation and partial pressures of oxygen and carbon dioxide, and lactate levels. From these parameters, the oxygenation index and the oxygen extraction ratio were calculated. These measurements were studied to evaluate whether rSO2 correlated significantly with the other parameters. RESULTS: The average age and weight of the patients were 27.3 months and 9.2 kg, respectively. The rSO2 correlated positively with both central venous oxygen saturation (r=0.73, P<.01) and mean arterial pressure (r=0.59, P<.01), and negatively with the oxygen extraction ratio (r=-0.7, P<.01). No correlation was found with the respiratory parameters. Concordance analysis established an acceptable Kappa index (> 0.4) between the rSO2 and central venous oxygen saturation, and between the rSO2 and oxygen extraction ratio. CONCLUSIONS: Regional cerebral oxygen saturation correlates well with hemodynamic parameters - mean arterial pressure, venous saturation, and the tissue oxygen extraction. However, it does not correlate with respiratory parameters.

[Oxygen extraction as a predictor of mortality in patients on high frequency ventilation]. / Extracción de oxígeno como predictor de mortalidad en pacientes con ventilación de alta frecuencia.

INTRODUCTION: The high frequency oscillatory ventilation (HFOV) may reduce cardiac output. The haemodynamics were analysed and predictors of mortality identified. PATIENTS AND METHODS: A total of 48 children with respiratory failure undergoing HFOV between January 2003 and December 2010 were included. The study design was prospective, observational, and descriptive. Inclusion criteria were based on the existence of hypoxemia. The variables studied were: arterial and central venous pressure, arterial pH, venous saturation and oxygen extraction ratio, with determinations performed prior to HFOV, during, and before turning to conventional ventilation. Prognostic factors were identified by bivariate analysis and a predictive model of mortality was developed. RESULTS: The mean age was 21 [4 to 72] months. On admission, PRISM scales and Murray were 33 and 2.8, PaO(2)/FiO(2) of 61 and oxygenation index of 35. After HFOV an increase in pH (P<.001), mean arterial pressure (P<.001) and venous saturation, and decreased venous pressure and O(2) extraction (P<.001), was obtained. The prognostic factors of mortality at 24 hours after starting HFOV were: FiO(2), PaO(2)/FiO(2), oxygenation index, shunt, pH, central venous pressure and mean arterial pressure, venous saturation, and O(2) extraction. The model developed at 12 hours, consisting of EtO(2) and SvcO(2) was able to predict death with a probability of 92.3%. CONCLUSIONS: HFOV improves haemodynamics. The model at 12 hours is the best predictor of death.

[Prognostic markers of mortality after congenital heart defect surgery]. / Marcadores pronósticos de mortalidad en el postoperatorio de las cardiopatías congénitas.

INTRODUCTION: Our aim is to identify risk factors for mortality after surgery for congenital heart disease in children, in order to establish indications for extracorporeal membrane oxygenation (ECMO). PATIENTS AND METHODS: One hundred and eighty six children underwent cardiac surgery with extracorporeal circulation from April 2007 to June 2009. The following parameters were measured serially during their stay in Paediatric Intensive Care (PICU): Arterial and venous blood pH, pCO2, base excess, oxygen saturation, arterio-venous oxygen saturation difference, oxygen extraction ratio, ventilatory dead space and intrapulmonary shunting. RESULTS: Hospital mortality was 13,4%. The following risk factors for mortality were identified: age, bypass time, inotropic score, lactate level upon arrival in PICU including its peak value and its rate of variation, mixed venous saturation, base excess, ventilatory dead space, oxygen extraction ratio, and intrapulmonary shunting. However, the strongest predictors of mortality were bypass time, lactate levels upon admission on PICU, and the peak lactate level. Multivariate analysis showed a lactate level of 6.3mmol/l and a high blood lactate for 24hours to be independent predictors of mortality. CONCLUSIONS: The peak lactate level is a strong predictor of mortality. As such, it would be a useful indicator of the need for ECMO support.

[Prognostic evaluation of arterial switch in the transposition of great arteries]. / Valoración pronóstica del switch arterial en la transposición de grandes arterias.

INTRODUCTION AND OBJECTIVES: The arterial switch is the procedure of choice for transposition of great arteries, with or without ventricular septal defect. The aim of this study was to identify risk factors for hospital mortality. METHODS: The study included 121 children between January 1994 and June 2008. Of these, 80 (66%) were diagnosed with intact ventricular septum, and 41 (34%) with ventricular septal defect. Variables were collected pre-operatively, during surgery, and postoperatively. RESULTS: The mean age was 11 [8 to 16] days and a mean weight of 3.5 [3.0 to 3.7] kg. A ventricular septal defect was closed in 11 children (9.1%). A total of 81.8% had a normal coronary pattern. There was delayed closure of the chest in 38 patients (31.4%). The hospital mortality was 11.6%, decreasing over the past 5 years to 2.1%. The weight, abnormal coronary pattern, time of cardiopulmonary bypass, mean arterial pressure at admission, pulmonary dead space, and delayed closure of the chest, were risk factors of mortality. The model that best predicts death, consists of the mean arterial pressure at admission, and delayed closure of the chest. CONCLUSIONS: The reduction in extracorporeal circulation time and the use of delayed closure of the chest, have helped to reduce mortality. The abnormal coronary pattern remains a risk factor for mortality. In children with delayed closure of the chest, a mean arterial pressure at admission ≥ 47.5 mmHg is a goal to achieve.