PubMed · 15912920
Pulmonary flow loops display characteric patterns which may indicate the underlying pathology of airway or parenchymal lung disease.
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J Mambretti-Zumwalt. 2000. Pulmonary flow loop.. https://pubmed.ncbi.nlm.nih.gov/15912920/
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Prolonged increases in fetal lung expansion stimulate fetal lung growth and development, but the effects on pulmonary hemodynamics are unknown. Our aim was to determine the effect of increased fetal lung expansion, induced by tracheal obstruction (TO), on pulmonary blood flow (PBF) and vascular resistance (PVR). Chronically catheterized fetal sheep (n = 6) underwent TO from 120 to 127 days of gestational age (term approximately 147 days); tracheas were not obstructed in control fetuses (n = 6). PBF, PVR, and changes to the PBF waveform were determined. TO significantly increased lung wet weight compared with control (166.3 +/- 20.2 vs. 102.0 +/- 18.8 g; P < 0.05). Despite the increase in intraluminal pressure caused by TO (5.0 +/- 0.9 vs. 2.4 +/- 1.0 mmHg; P < 0.001), PBF and PVR were similar between groups after 7 days (TO 28.1 +/- 3.2 vs. control 34.1 +/- 10.0 ml.min(-1).100 g lung wt(-1)). However, TO markedly altered pulmonary hemodynamics associated with accentuated fetal breathing movements, causing a reduction rather than an increase in PBF at 7 days of TO. To account for the increase in intraluminal pressure, the pressure was equalized by draining the lungs of liquid on day 7 of TO. Pressure equalization increased PBF from 36.8 +/- 5.2 to 112.4 +/- 22.8 ml/min (P = 0.01) and markedly altered the PBF waveform. These studies provide further evidence to indicate that intraluminal pressure is an important determinant of PBF and PVR in the fetus. We suggest that the increase in PBF associated with pressure equalization following TO reflects an increase in growth of the pulmonary vascular bed, leading to an increase in its cross-sectional area.
This article addresses the scope, etiology, important associations and imaging features of congenital bronchopulmonary foregut malformations. Etiologic concepts, including airway obstruction and vascular anomalies, are highlighted. Technical imaging advances, especially CT and MR, have greatly enhanced our diagnostic abilities in evaluating these lesions; however, thorough and careful assessment of all aspects of the malformation is still necessary. Several specific lesions are discussed in more detail, particularly regarding controversial issues in classification, understanding, imaging and management.
Of the several million patients who undergo surgery in North America annually, a large proportion undergo intubation of the trachea. In approximately 90% of these patients, the endotracheal tube is introduced using a traditional laryngoscope with a battery in the handle and a small bulb near the tip of the blade. This bulb provides a limited and often dim view of the glottic structures. In about 10% of cases, the patient is intubated using a flexible fiberoptic intubating scope. The authors have developed a video laryngoscope that preserves the standard blade configuration with a modified handle. A 3-mm image light guide is built into the blade, replacing the bulb. A small TV camera with an incorporated light bundle is inserted into the handle. A wide-angle panoramic view of the upper airway anatomy is displayed on a TV screen, which can be positioned at a convenient working distance. The use of a TV monitor is a well-accepted standard during minimally invasive surgical procedures.