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Circulatory effects of fast ventilator rates in preterm infants
A C Fenton1, D J Field, K L Woods
1Department of Child Health, Leicester Royal Infirmary.
Insights
High frequency positive pressure ventilation (HFPPV) in preterm infants with respiratory distress syndrome did not show cardiovascular compromise from positive end-expiratory pressure (PEEP). However, further study is needed regarding cerebrovascular regulation at faster HFPPV rates.
Area of Science:
- Neonatal Medicine
- Pediatric Respiratory Medicine
- Intensive Care
Background:
- High frequency positive pressure ventilation (HFPPV) is explored as an alternative to conventional ventilation for preterm infants with idiopathic respiratory distress syndrome.
- A potential concern with HFPPV is cardiovascular compromise due to inadvertent positive end-expiratory pressure (PEEP).
Purpose of the Study:
- To evaluate the cardiovascular effects, specifically inadvertent PEEP, of HFPPV in preterm infants with respiratory distress syndrome.
- To assess the influence of HFPPV on arterial blood pressure and cerebral blood flow velocity in this population.
Main Methods:
- A study involving 20 preterm infants with idiopathic respiratory distress syndrome receiving HFPPV (up to 100 breaths/minute).
- Analysis of arterial blood pressure and cerebral blood flow velocity changes in relation to arterial blood gases.
- Assessment for any cardiovascular effects attributable to inadvertent PEEP.
Main Results:
- Changes in arterial blood pressure and cerebral blood flow velocity were primarily linked to alterations in arterial blood gases, not inadvertent PEEP.
- Observed decreases in arterial carbon dioxide and oxygen tensions were predictable.
- At the highest ventilation rates, cerebral blood flow velocity was significantly affected by blood pressure changes, suggesting potential impaired cerebrovascular regulation.
Conclusions:
- HFPPV at rates up to 100/minute did not demonstrate cardiovascular compromise related to inadvertent PEEP in preterm infants with respiratory distress syndrome.
- Further investigation is warranted to understand the role of HFPPV in cerebrovascular regulation, especially at faster rates, considering potential confounding factors like illness severity or paralysis.
Abstract:
High frequency positive pressure ventilation has been suggested to result in a lower incidence of respiratory complications in preterm infants with idiopathic respiratory distress syndrome compared with ventilation at conventional rates. A possible disadvantage is compromise of the infant's cardiovascular condition secondary to inadvertent positive end expiratory pressure (PEEP). In a group of 20 such infants treated with high frequency positive pressure ventilation (rates of up to 100/minute) and analysed, changes in arterial blood pressure and cerebral blood flow velocity were largely influenced by changes in arterial blood gases, and no effect could be attributed to inadvertent PEEP. In addition, the observed fall in both arterial carbon dioxide and oxygen tensions could be readily predicted for theoretical reasons. Under certain conditions at the fastest rates used, cerebral blood flow velocity was significantly influenced by changes in blood pressure, which may indicate impaired cerebrovascular regulation. Though other factors (such as the severity of the infants' illness or the use of paralysis) may have been responsible for this apparent blood pressure passivity, the role of high frequency positive pressure ventilation in such infants warrants further study.