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Background: Metabolic or mixed (metabolic and respiratory) acidosis are commonly encountered problems in the low birth weight (LBW) infant after delivery, and they may contribute to mortality and morbidity. Causes for the lactic acidosis are multiple and include maternal, placental and fetal factors. It is unclear whether metabolic acidaemia in the first 24 hours of life in LBW infants should be corrected by rapid infusion of alkali., Objectives: The main objective was to assess the short and long-term effects of the rapid correction of early (first 24 hours) metabolic acidaemia in LBW (<2500g birth weight) neonates., Search Strategy: Searches were undertaken of MEDLINE from October 2001 back to 1966 and the Cochrane Controlled Trials Register (Cochrane Library, Issue 4, 2001). The title and abstract of each retrieved study were examined to assess eligibility. If there was uncertainty, the full paper was examined., Selection Criteria: Types of studies All randomised controlled trials where short or long term effects of treatment with alkalising agents by rapid infusion were compared with placebo or no treatment, or where rapid infusion of alkalising agents was compared with slow infusion. Types of participants Newborn infants with birth weight <2500g and less than 24 hours of age with proven metabolic acidaemia (on arterial blood gas). Types of interventions Rapid correction of acidaemia with alkalising agents (sodium bicarbonate and/or THAM) given as a bolus over 5 minutes or less compared with either placebo, no intervention or slow infusion (>5 minutes). Types of outcome measures 1) maximal oxygen requirement in first 24 hours 2) duration of oxygen therapy 3) need for and duration of assisted ventilation 4) intraventricular haemorrhage and/or periventricular leucomalacia 5) survival to discharge 6) long term survival (to 24 months of age) 7) neurological and developmental outcome at 24 months of age, Data Collection and Analysis: Each reviewer assessed eligibility, trial quality and extracted data separately, then compared and resolved differences. Study authors were contacted for additional information if necessary., Main Results: No studies were found meeting the criteria for inclusion in this review., Reviewer's Conclusions: There is no evidence available from randomised controlled trials to support or refute the rapid correction of metabolic acidaemia, in LBW infants in the first 24 hours of life, as compared with slow or no correction.

There are limited data on the volumes used to ventilate infants with respiratory distress syndrome (RDS). There are no data on the volumes to aim for to avoid hypocapnia or unacceptable levels of hypercapnia. In this pilot study we measured minute volumes (MV) in ventilated infants to determine whether MV can predict arterial carbon dioxide (PaCO(2)) within acceptable parameters. Low birth weight infants (n = 14) mechanically ventilated for RDS had lung function recorded (n = 53) as an arterial blood gas was taken. MVs were plotted against PaCO(2) giving the regression equation for prediction of PaCO(2) (mm Hg) with MV (ml/kg/min): PaCO(2) = 58.3 - 0.075 x MV, r = 0.62, r(2) = 0.38, p < 0.001, residual variance (s(2)) of 52.7 (s = 7.26). 95% CI give a predicted PaCO(2) +/- 15 mm Hg for a given MV. A MV of 200 ml/kg/min predicts a PaCO(2) of 43 mm Hg (95% Cl 29-58). PaCO(2) correlates reasonably well with MV. Setting appropriate MVs may allow closer targeting of PaCO(2), and prevent over- or under-ventilation., (Copyright 2002 S. Karger AG, Basel)