ISSN:
1615-2573
Keywords:
Pulmonary circulation
;
Pulsed Doppler
;
Ultrasound
;
Pulmonary blood velocity
;
Lambs
;
Pulmonary hypertension
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary To provide a comprehensive picture of the interaction between abnormal pulmonary hemodynamics and pulmonary blood velocity patterns in the young, we have developed infant animal models of pulmonary hypertension and/or elevated pulmonary blood flow. This report focuses on relationships between selected velocity waveform shape-dependent variables — i.e., the time between the onset of systole and peak velocity (rise time), the time during which velocity remains at 〉90% of that peak (90% time), and flow reversal patterns — and traditional hemodynamic indications of pulmonary vascular impairment, i.e., elevated pulmonary artery pressure and pulmonary vascular resistance. Studies were performed on 36 anesthetized, open-chest, one-month-old lambs with normal pulmonary circulations or with abnormal conditions that had been initiated during the first few days of life via (1) a central venous injection of monocrotaline pyrrole (hypertension) or (2) a side-to-side anastomosis between the common carotid artery and jugular vein (elevated flow). Animals with large shunts (shunt open cardiac output/shunt closed cardiac output 〉2.1) had both elevated pressures and flows. The tightest correlations (linear and log-linear) were found between unindexed pulmonary vascular resistance and waveform variables, the most reliable being 90% time (r = −0.838), 90% time + rise time (r = −0.838), and 90% time × rise time (r = −0.824). The best correlate to mean pulmonary artery pressure was 90% time + rise time (r = −0.713). Combined rise time and 90% time variables yielded results that exceeded 90% sensitivity and specificity levels in diagnosing elevated pulmonary vascular resistance (〉700 dyne-sec/cm5). Absence of flow reversal in central and anterior regions was an indicator of markedly elevated pulmonary artery pressures (mean 〉28mmHg). The findings of this report (1) demonstrate the successful development of animal models that mimic a broad spectrum of relevant pulmonary hemodynamics in infants and children with compromised pulmonary circulations and (2) point to shape variables that should improve noninvasive assessment of elevated pulmonary vascular resistance.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01751939
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