Volume Guarantee Ventilation in Preterm Infants With Frequent Episodes of Hypoxemia

Volume Guarantee Ventilation in Preterm Infants With Frequent Episodes of Hypoxemia

Preterm infants undergoing mechanical ventilation often present with respiratory instability which leads to fluctuations in ventilation and oxygenation. In conventional modes of mechanical ventilation used in these patients, the ventilator delivers breaths at a set rate and a constant peak inspiratory pressure.

We have demonstrated that spontaneous episodes of hypoxemia in mechanically ventilated preterm infants are frequently triggered by a loss in end-expiratory lung volume followed by decrease in tidal volume. This is due to a reduction in respiratory system compliance and increase in airway resistance.

Volume Guarantee ventilation is a mode of ventilation in which ventilator measures the exhaled tidal volume of each ventilator breath and automatically adjusts the peak inspiratory pressure to deliver the set tidal volume. We have previously shown that Volume Guarantee reduced the severity and duration of hypoxemia episodes during a period of 2 hours in preterm infants The study hypothesis is that Volume Guarantee ventilation will decrease the duration of episodes of hypoxemia when compared to conventional mechanical ventilation during routine clinical conditions and over longer periods of time.

The objective of the study is to evaluate the effects of Volume Guarantee on the duration, severity and frequency of episodes of hypoxemia in mechanically ventilated preterm infants who present with frequent hypoxemia episodes in comparison to conventional ventilation over two periods of 24 hours each and under routine clinical conditions.

Inclusion Criteria:

• Born at less than 32 weeks of gestational age.
• Requiring mechanical ventilation on a mandatory ventilator rate greater than or equal to 20 per minute and receiving a mean tidal volume of at least 4 ml/kg.
• Presenting with 4 or more episodes of hypoxemia, defined as oxygen saturation less than 75%, in the 8 hours prior to the study.

Exclusion Criteria:

• Major congenital anomalies.
• Hemodynamic instability requiring inotropes within 72 hours prior to the study
• Culture proven sepsis within 72 hours prior to the study.
• Diagnosis of pulmonary interstitial emphysema or pneumothorax within the 72 hours prior to the study.