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Effect of intermittent positive pressure ventilation on diastolic ventricular filling patterns in premature infants
E Maroto1, J C Fouron, G Teyssier
1Department of Pediatrics, Sainte-Justine Hospital, University of Montreal, Quebec, Canada.
Insights
Positive pressure ventilation impacts preterm infants' ventricular filling. Inspiration enhances left ventricular filling while decreasing right ventricular filling, affecting diastolic function assessment.
Area of Science:
- Neonatal Cardiology
- Pediatric Critical Care Medicine
- Cardiovascular Physiology
Background:
- Assessing ventricular diastolic function in preterm infants on positive pressure ventilation is crucial.
- Intermittent positive pressure ventilation (IPPV) can alter hemodynamic patterns.
- Understanding respiratory effects on ventricular filling is essential for clinical management.
Purpose of the Study:
- To investigate Doppler echocardiographic ventricular filling patterns in preterm neonates during IPPV.
- To compare ventricular filling during inspiratory and expiratory phases of IPPV.
- To determine the impact of IPPV on left and right ventricular diastolic function.
Main Methods:
- Doppler echocardiography was performed on eleven preterm infants receiving IPPV.
- Measurements included peak velocities (VE, VA) and diastolic velocity-time integrals (IE, IA) for early and late ventricular filling.
- Ratios of VE/VA and IE/IA were calculated to assess filling patterns.
Main Results:
- Mitral inflow velocities (early and late filling) were significantly higher during inspiration.
- The ratio of early to late filling (E/A) remained consistently <1 and showed no significant respiratory variation.
- Right ventricular inflow patterns were opposite to left ventricular patterns, with decreased velocities during inspiration.
Conclusions:
- IPPV significantly alters ventricular filling dynamics in preterm infants.
- Inspiration enhances left ventricular filling but decreases right ventricular filling.
- Observed changes differ from spontaneous breathing and necessitate consideration in diastolic function assessment during assisted ventilation.
Abstract:
Eleven preterm newborn infants had a Doppler echocardiographic examination of their ventricular filling patterns during intermittent positive pressure ventilation. Peak velocity during early ventricular filling (VE) and during atrial systole (VA) and diastolic velocity-time integral of early (IE) and late (IA) ventricular filling caused by atrial contraction were measured. The ratios of VE/VA and IE/IA were also calculated. Diastolic peak velocities, as well as the diastolic velocity-time integral of early and late ventricular filling measured through the mitral valve were significantly higher during inspiration. The peak of the wave representing the velocity during atrial systole (A) was always higher than the peak of the wave representing the velocity of early ventricular filling (E). As a result, the ratio of these two variables (E/A) was always less than 1, showing no significant variation from inspiration to expiration. The flow patterns into the right ventricle were the opposite of those observed through the mitral valve. During inspiration, a significant decrease (p less than 0.001) in peak and time integral velocities of both the early ventricular filling and atrial systole waves was observed. Heart rate did not vary with respiration. It is concluded that during positive pressure ventilation, inspiration decreases right ventricular filling and enhances left ventricular filling. Opposite changes are recorded during expiration. Early and late phases of diastolic filling are equally affected. These changes are different from those observed during spontaneous breathing and should be taken into account in the assessment of diastolic ventricular function in preterm infants requiring assisted ventilation.