[Oxygen extraction as a predictor of mortality in patients on high frequency ventilation].
BACKGROUND
The high frequency oscillatory ventilation (HFOV) may reduce cardiac output. The haemodynamics were analysed and predictors of mortality identified.


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.
Unidad de Gestión Clínica de Cuidados Críticos y Urgencias, Hospital Infantil Universitario Virgen del Rocío, Seville, Spain. garcier@gmail.com
J A
JA
García-Hernández
A
A
Vázquez Florido
A I
AI
Martínez-López
J M
JM
Praena-Fernández
A
A
Cayuela-Domínguez
J
J
Cano-Franco
M
M
Loscertales-Abril
D002675:Child, Preschool; D005260:Female; D006439:Hemodynamics; D006612:High-Frequency Ventilation; D006801:Humans; D007223:Infant; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D011379:Prognosis; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000378:metabolism / Q000401:mortality* / Q000628:therapy*
D010100:Oxygen