Persistently elevated right ventricular index of myocardial performance in preterm infants with incipient bronchopulmonary dysplasia.
OBJECTIVE
Elevated pulmonary vascular resistance occurs during the first days after birth in all newborn infants and persists in infants at risk for bronchopulmonary dysplasia (BPD). It is difficult to measure in a non-invasive fashion. We assessed the usefulness of the right ventricular index of myocardial performance (RIMP) to estimate pulmonary vascular resistance in very low birth weight infants.


METHODS
Prospective echocardiography on day of life (DOL) 2, 7, 14, and 28 in 121 preterm infants (median [quartiles] gestational age 28 [26]-[29] weeks, birth weight 998 [743-1225] g) of whom 36 developed BPD (oxygen supplementation at 36 postmenstrual weeks).


RESULTS
RIMP derived by conventional pulsed Doppler technique was unrelated to heart rate or mean blood pressure. RIMP on DOL 2 was similar in infants who subsequently did (0.39 [0.33-0.55]) and did not develop BPD (0.39 [0.28-0.51], p = 0.467). RIMP declined steadily in non-BPD infants but not in BPD infants (DOL 7: 0.31[0.22-0.39] vs. 0.35[0.29-0.48], p = 0.014; DOL 14: 0.23[0.17-0.30] vs. 0.35[0.25-0.43], p<0.001; DOL 28: 0.21[0.15-0.28] vs. 0.31 [0.21-0.35], p = 0.015).


CONCLUSIONS
In preterm infants, a decline in RIMP after birth was not observed in those with incipient BPD. The pattern of RIMP measured in preterm infants is commensurate with that of pulmonary vascular resistance.
Department of Neonatology, Charité University Medical Center, Berlin, Germany. christoph.czernik@charite.de
Christoph
C
Czernik
Stefanie
S
Rhode
Boris
B
Metze
Gerd
G
Schmalisch
Christoph
C
Bührer
D001997:Bronchopulmonary Dysplasia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004374:Ductus Arteriosus, Patent / Q000000981:diagnostic imaging / Q000503:physiopathology; D015150:Echocardiography, Doppler; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008297:Male; D009206:Myocardium / Q000473:pathology*; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D012307:Risk Factors