Ventilation and stress in preterm infants: High frequency ventilation is not an additional stressor

Aim. To study the hypothesis that high frequency ventilation (HFV) is an additional stressor compared to conventional ventilation (CV). Methodology. A prospective explorative cohort study in a consecutive sample of 50 preterm infants (<37 gestational age) with Idiopathic Respiratory Distress Syndrome admitted to a Level III Neonatal Intensive Care Unit. During the first three days of ventilation stress was assessed by means of the Comfort scale (CS). Results. 35 Infants received HFV and 15 CV. The HFV group was of significantly lower gestational age (p=.003), had a significantly lower birth weight (p=.017) and were significantly more severely ill (p<.0001). Stress scores between groups were comparable, adjustment for baseline differences revealed no differences in scores during the first 3 days of ventilation. Of all CS assessments, 34.0% in the HFV group and 35.6% in the CV group indicated stress (score ≥ 20). Conclusion. Stress during the first three days of mechanical ventilation using the CS did not reveal any difference between high frequency and conventional ventilated preterm infants. Routine use of sedatives seems insufficient to prevent high stress scores.