Objective Mild hypothermia (MH) (rectal temperature 33–34 C) appears neuroprotective. Deep hypothermia (DH) (rectal temperature 30–33 C) could be a new therapeutic strategy for treating severe hypoxic-ischemic term infants. The aim of this study was to describe ventilator changes during DH and MH.

Methods 28 term asphyxiated newborns were enrolled: 20 DH and 8 MH. Mechanical ventilation was set to maintain an arterial oxygen saturation of 92–95% with PaO₂ between 50 and 60 mmHg and PaCO₂ between 40 and 45 mmHg.

Results 14 DH (70%) and 4 MH patients (50%) were treated with SIMV. In the DH group, 7 patients (35%) were maintained in room air and 13 (65%) required oxygen (FiO₂ 0.27–1.0). In MH group, 4 cases (50%) required oxygen (FiO₂ 0.22–1.0) and 4 (50%) room air. Mean of hours of ventilation were 48.11 (44.11) hrs in DH and 105.5 (69.69) hrs in MH; there was no statistically significant difference between the two groups (p = 0.095). Mean of hours of oxygen required were 88.5 (91.95) hrs in DH and 231 (58.298) hrs in MH (p = 0.010). There was no statistical difference in the highest quantity of FiO₂ between the DH and MH (P = 0.747).

Conclusions Mild and deep hypothermia did not produce any change in mean of hours of ventilation. However there is a statistically significant difference in hours of oxygen support. This discrepancy is probably correlated to a reduction in oxygen consumption, for a decrease in metabolic state in DH group compared with MH group.