Abstract
Background: Survival of neonates requiring intensive care has improved, but many suffer ventilator-related complications. This thesis aims to optimise use of ventilation techniques, with a focus on infants born at term.Hypotheses:
In infants with acute respiratory failure, volume-targeted ventilation (VTV) will be superior to pressure-limited ventilation (PLV).
Proportional assist ventilation (PAV) will be effective in reducing elastic and resistive work of breathing (WOB) in an in vitro experiment.
Methods: A series of studies were undertaken.
National survey of practice in relation to respiratory support in term infants
Comparison of WOB at different levels of volume-targeting in term infants
Randomised comparison of VTV and PLV in preterm infants
Analysis of spontaneous respiratory activity in ventilated term infants
In vitro study of effect of elastic and resistive unloading on WOB during PAV Results: Respiratory support practices for term-born infants differed between different levels of care. In term infants, WOB was higher at 4ml/kg compared to 5 and 6ml/kg. In preterm infants, there was no difference in time to achieve weaning criteria on VTV versus PLV. Fewer infants on VTV experienced hypocarbia. Patterns of patient-ventilator interaction were described for term-born infants. Active expiration was more common on SIMV versus CMV, and less common on triggered ventilation at 4ml/kg compared to 6ml/kg or no volume-targeting. Using PAV, elastic unloading was more effective than resistive unloading in reducing WOB.
| Date of Award | 2015 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Anne Greenough (Supervisor) & Gerrard Rafferty (Supervisor) |