| Abstrakt: |
When right ventricular ejection time (RVET) and RV pre-ejection period (RPEP) are measured by echocardiography, a RPEP/RVET ratio greater than 0.35 has been associated with increased pulmonary vascular resistance (Circulation 52:642, 1975). 4 children with alveolar hypoventilation due to enlarged tonsils and adenoids, or posteriorly displaced tongue, were studied. Onset of upper air-way obstruction ranged from birth to 2-1/2 years. The patients had a low PaO2(39-78 mm Hg), elevated PaCO2(50-56 mm Hg) during sleep, right atrial and right ventricular hypertrophy by electro-cardiogram (ECG) and vectorcardiogram (VCG), and cardiomegaly by roentgenogram. Pulmonary artery pressures (PAP) during cardiac catheterization ranged from 80/30 to 80/50 mm Hg (m=55) and RPEP/RVET was greater than 0.5 in each case (normal 0.24±0.06). One patient, who was not catheterized, had an RPEP/RVET of 0.37. Oxygen administration or intubation during cardiac catheterization reduced PAP to 40/10 (m=30) and 50/10 (m=30) in two cases, and RPEP/RVET decreased simultaneously to less than 0.3. The other children underwent tonsillectomy and adenoidectomy. RPEP/RVET decreased postoperatively from 0.5 to 0.3 and 0.37 to 0.3 respectively, and sleeping blood gases, ECG, VCG and chest roentgenogram reverted to normal. Echocardiography is non invasive, reflects changes in PAP and can be used for sequential evaluation of children with upper airway obstruction. Further experience may yield objective criteria for operative intervention. |
