Effect of chronic hypoxia on pulmonary artery blood velocity in rats as assessed by electrocardiography-triggered three-dimensional time-resolved MR angiography.

Pulmonary arterial hypertension (PAH) is a severe disease that leads to increased pulmonary vascular resistance and right heart failure. Noninvasive methods are needed to detect changes in the pulmonary artery circulation during PAH establishment and/or treatment. Pulmonary blood flow velocity can be evaluated by dynamic MR angiography, although the relevance of such data in the context of PAH remains to be demonstrated. A novel dynamic MR angiography technique was used in this work to measure blood flow velocity in the pulmonary arteries of the same living animals, before and after the establishment of chronic hypoxia-induced PAH. Chronic hypoxia decreased significantly the blood flow velocity (43.8 ± 4.9 vs 24.3 ± 8.7 cm/s) on electrocardiography-triggered time-resolved angiograms. In parallel, chronic hypoxia-induced PAH was confirmed from invasive measurements of the mean pulmonary arterial pressure (32.1 ± 4.8 vs 12.5 ± 2.2 mmHg) and the ratio of the right ventricle weight to the left ventricle plus septum weight (Fulton index: 0.54 ± 0.06 vs 0.27 ± 0.04). This study demonstrates the potential interest of dynamic MR angiography for the investigation of experimental models and for the evaluation of treatment efficacy.

Propranolol for severe infantile hemangiomas: follow-up report.

OBJECTIVE: Infantile hemangiomas (IHs) are the most-common soft-tissue tumors of infancy. We report the use of propranolol to control the growth phase of IHs. METHODS: Propranolol was given to 32 children (21 girls; mean age at onset of treatment: 4.2 months) after clinical and ultrasound evaluations. After electrocardiographic and echocardiographic evaluations, propranolol was administered with a starting dose of 2 to 3 mg/kg per day, given in 2 or 3 divided doses. Blood pressure and heart rate were monitored during the first 6 hours of treatment. In the absence of side effects, treatment was continued at home and the child was reevaluated after 10 days of treatment and then every month. Ultrasound measurements were performed after 60 days of treatment. RESULTS: Immediate effects on color and growth were noted in all cases and were especially dramatic in cases of dyspnea, hemodynamic compromise, or palpebral occlusion. In ulcerated IHs, complete healing occurred in <2 months. Objective clinical and ultrasound evidence of longer-term regression was seen in 2 months. Systemic corticosteroid treatment could be stopped within a few weeks. Treatment was administered for a mean total duration of 6.1 months. Relapses were mild and responded to retreatment. Side effects were limited and mild. One patient discontinued treatment because of wheezing. CONCLUSION: Propranolol administered orally at 2 to 3 mg/kg per day has a consistent, rapid, therapeutic effect, leading to considerable shortening of the natural course of IHs, with good clinical tolerance.

Efficacy and tolerance of high-dose inhaled ipratropium bromide vs. terbutaline in intubated premature human neonates.

BACKGROUND: There is insufficient data to reliably assess the benefit of bronchodilators in ventilated premature neonates. OBJECTIVES: To compare the efficacy/tolerance of inhaled ipratropium bromide (IB) vs. terbutaline (T) and to describe factors associated with their efficacy. METHODS: A cross-over randomized controlled double-blind trial including intubated neonates with respiratory distress syndrome. Two puffs of IB or T were administered at 0, 20, 40 min. Passive respiratory system resistance (Rrs) and compliance (Crs) were measured at 0, 20, 40, 60 min. A positive response was defined as a >2 individual coefficients of variation decrease in Rrs or increase in Crs. RESULTS: Twenty-one infants (gestational age (mean +/- SD): 27.3 +/- 1.6 weeks; birth weight: 947 +/- 250 g; postnatal age: 20 +/- 9 days) were included. At 60 min, no treatment effect for Rrs and Crs could be identified (cross-over analysis). Overall data (irrespective of order of administration) showed that after 6 puffs, the decrease in Rrs was greater in the IB vs. T group (-17.0 +/- 22.2% vs. -11.3 +/- 26.7%, respectively (NS)). Thirty-eight percent of infants responded to IB vs. 43% to T. However, in 19% of patients, decreased Crs was observed after 6 puffs of T. No marker of a positive or paradoxical response could be identified. Treatment was well-tolerated. CONCLUSION: High doses of bronchodilators are required in ventilated neonates, but the positive response rate was <50%. Their long-term benefit remains to be proven.