Inflation time in mechanical ventilation of preterm neonates
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1Department of Child Health, King's College Hospital, London, UK.
Insights
Fast mechanical ventilation rates are most effective for preterm infants. Optimizing inflation time based on spontaneous inspiratory time ensures synchronous respiration and maximum minute volume for neonates.
Area of Science:
- Neonatal physiology
- Respiratory support
Background:
- Mechanical ventilation is crucial for preterm infants.
- Determining optimal ventilation parameters is challenging.
- Spontaneous inspiratory time influences ventilation efficacy.
Purpose of the Study:
- To investigate the relationship between preterm infant inspiratory time and optimal mechanical ventilation inflation time.
- To define optimum inflation time for synchronous respiration and maximum minute volume.
- To assess the efficacy of fast ventilator rates in preterm neonates.
Main Methods:
- Studied 12 preterm infants on 14 occasions.
- Ventilated infants at rates of 60-120 breaths/min with an I:E ratio of 1:1.2.
- Measured spontaneous inspiratory time during disconnection and continuous positive airways pressure (CPAP).
Main Results:
- Inspiratory time during disconnection was shorter than on CPAP (P<0.01).
- Shortest inflation times yielded the most synchronous respiration and greatest minute volume (P<0.01).
- Fast ventilator rates were most efficacious for preterm neonates.
Conclusions:
- Optimal inflation time in preterm neonates is achieved with fast ventilator rates.
- Ventilator rates can be estimated using spontaneous inspiratory time and gestational age.
- Fast rates improve synchrony and minute volume in neonatal mechanical ventilation.
Abstract:
The importance of the preterm infant's inspiratory time in determining the optimum inflation time during mechanical ventilation was investigated. The optimum inflation time was defined as that which was most commonly associated with synchronous respiration and maximum minute volume. Twelve preterm infants were studied on 14 occasions. They were ventilated at rates of 60, 75, 90, 105 and 120 breaths/min, with an inspiratory: expiratory ratio of 1:1.2. These rates were chosen as they resulted in inflation times approximating to the spontaneous inspiratory time measured during a brief period of disconnection, on continuous positive airways pressure (CPAP), and greater than that measured on CPAP. Inspiratory time during disconnection was always shorter than that measured on CPAP (P less than 0.01). Synchrony was most commonly provoked and minute volume greatest at the shortest inflation time (P less than 0.01). We conclude fast ventilator rates are most efficacious for preterm neonates. As previously shown, this rate can be estimated by examining the standard reference range of rates in relation to gestational age.