Biomedical subjects
Publications and source records attributed to N T Griscom.
Tracheobronchomegaly is rarely reported in neonates. We present five cases of tracheobronchomegaly occurring in neonates receiving intensive ventilatory and oxygen support. Barotrauma is speculated to be the primary pathophysiologic factor in these cases.
The possibility of tracheal enlargement in older patients with cystic fibrosis was investigated by examining chest radiographs of 42 living adults (age range, 30-45 years) who had the disease and by performing postmortem studies (anatomic and histologic) on the tracheas of older adolescents and young adults (age range, 15-33 years) who died with the disease. Anteroposterior tracheal diameters were enlarged in 41 of the living adults. The average diameter was 1.3 +/- 0.9 SD standard deviations above the mean for normal subjects. These increases did not correlate with severity of pulmonary disease as judged radiographically. Enlargement seemed to have developed slowly, over many years or decades. A few tracheas were grossly irregular in outline. One patient had a severely increased transverse diameter of 4.7 standard deviations above the normal mean. The average transverse diameter was 0.3 +/- 1.1 SD standard deviations above the normal mean. The tracheas of adults and older adolescents who had died with cystic fibrosis were abnormally flaccid. Some collapsed suddenly during deflation. Microscopic examination showed instances of severe inflammation, focal epithelial metaplasia, hypertrophy and hyperplasia of the mucous glands, degenerative changes in the muscle of the pars membranacea, and death of cartilage cells. The structural changes shown histologically and the many decades of frequent, vigorous coughing may be important in the enlargement of these tracheas and their flaccidity.
Biplane roentgenography, axial roentgenography, and fluoroscopy are the usual roentgenographic methods of measuring femoral anteversion. These methods use a strict geometrical definition of anteversion. The computerized tomography method of measuring anteversion that was developed recently, and is now widely used, does not adhere to the accepted definition of anteversion and has not been tested for accuracy in a large series. In the present study, the widely used computerized-tomography method of measuring anteversion was tested on thirty-two femoral specimens. With that method, anteversion was consistently underestimated by an average of 10 degrees compared with direct measurements and was reproducible only to within +/- 3.6 degrees. Therefore, a new method of measuring anteversion using computerized tomography was developed. It was shown to be accurate to +/- 1 degree, as tested on the same specimens. This study demonstrated geometrically why the currently practiced computerized-tomography method of selecting the points that are used to define the axis of the femoral neck is not consistent with geometrical definitions of anteversion. A more accurate method for both defining the axis of the femoral neck and measuring femoral anteversion is described and recommended for clinical use.
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Computed tomography measured the lengths, anteroposterior (AP) diameters, transverse diameters, cross-sectional areas, and contained volumes of the tracheas of 130 subjects in their first two decades. Patients below age 6 were scanned at low lung volumes. The others were scanned at or near total lung capacity. The results are shown by age and gender. There were no differences between boys and girls until age 14, when girls' tracheas stopped growing. The data suggest that male tracheas continue to enlarge (but not lengthen) for a time after growth in height ceases. Mean transverse diameters tended to be greater than mean AP diameters to the age of 6; the diameters were then nearly identical until age 18, when the AP diameters usually became slightly larger. The tracheas were nearly round in cross section, especially at high lung volumes. In individual tracheas, changes from level to level were small. These measurements should be useful in the detection of tracheal abnormalities, in problems in respiratory physiology, and in endotracheal intubation, endoscopy, and tracheostomy.
Changes in lung volume can be partitioned into volume displacements of the rib cage and abdomen. Abdominal displacements are often used as estimates of diaphragmatic displacements and changes in lengthening of diaphragmatic muscle. We used X-rays, ultrasound, and linear measurements of thoracic and abdominal diameters to estimate relationships among lung volume, thoracoabdominal configuration and diaphragmatic length, and we found that diaphragmatic length was strongly dependent on rib cage as well as abdominal displacement. In three subjects, the diaphragm shortened 57-85% as much during a breath made without abdominal displacement as during a normal breath in which the abdominal wall moved outward with the rib cage. We conclude that changes in diaphragmatic length can be estimated from surface measurements without radiation and that the length of the diaphragm cannot be estimated from displacements of the abdominal wall alone.
Using computed tomography, we measured the tracheas of 100 subjects younger than 20 yr of age. The 10 youngest were sleeping. The other 90 were awake, and most were measured near total lung capacity. Tracheal length, mean anteroposterior diameter, mean transverse diameter, mean cross-sectional area, and contained volume were plotted against body height for all 100 subjects. The relationships of these dimensions to body height were derived for the 90 subjects examined awake. The resulting regressions had r values of 0.88 to 0.92. The exponents for height were 1.22 to 1.37 for the linear dimensions, 2.58 for area, and 3.80 for volume. We found no differences between the sexes. Variability in diameters and area along individual tracheas was small, especially after early childhood. Such variability as occurred tended to preserve shape slightly more than size. This constancy allows accurate prediction of tracheal area from either tracheal diameter.
To determine the accuracy and reproducibility of measurements of airway area by acoustic reflection (AAAR) we made repeated measurements of tracheal areas in human volunteers, glass airway models, and excised canine tracheae. In 10 adult males, the mean ratio of tracheal AAAR to tracheal areas determined roentgenographically was not significantly different from one (1.06 +/- 0.13 SD). Within-run variability was 10 +/- 4% (CV), mean intrasubject day-to-day variability was 9 +/- 4% (CV). A custom-made mouthpiece is necessary for accurate measurements of AAAR. Mean variability related to differences in mouthpiece construction was 7 +/- 6% (CV). The effect of variations in upper airway and glottic sizes on tracheal AAAR measurements was investigated using glass airway models. In model studies, tracheal AAAR measurements were found to be independent of changes in proximal airway size for glottic apertures greater than or equal to 1 cm2 and upper airway areas less than or equal to 8 cm2. Tracheal area was, however, overestimated by 20% in the rigid-walled glass models. The effects of airway wall rigidity were qualitatively investigated by comparing acoustic and roentgenographic measurements of excised canine tracheae surrounded by either air or petroleum jelly. Differences in the accuracy of measurements of AAAR in vitro and in vivo are probably due to differences in airway wall inertance. These studies suggest that the measurement of AAAR yields an accurate and reproducible result that may be clinically useful for the noninvasive detection of changes in central airway geometry.
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We used CT to examine the tracheas of two healthy adults at functional residual capacity, first at an intratracheal pressure of +20-cm H2O and then at -20-cm H2O. In the intrathoracic portions of the tracheas there was little change in cross-sectional area between the two pressures. However, in the neck the cross-sectional areas decreased by about one third from the higher pressure to the lower. The membranous posterior wall of the woman's extrathoracic trachea bulged backwards strikingly at the higher pressure but was drawn well into the tracheal lumen at the lower pressure. The two tracheas were 6% and 12% shorter at the lower pressure, and the intratracheal volume was 17% to 23% less. The data show that the size and shape of the extrathoracic portion of the normal adult trachea are very responsive to moderate changes in intraluminal pressure.
Computed tomographic scanning was used to investigate the shape in cross section of the lumen of the pediatric trachea. Seven children up to age 10 (mostly age 6 or older), six girls aged 10-19, and six boys aged 10-19 had scans of their tracheas, mostly during breath-holding not far from total lung capacity. At these ages and under these circumstances, the trachea may be slightly narrow just below the larynx, and it broadens just above its bifurcation. At other levels, it is only mildly or moderately off-circular although there are variations from patient to patient and from level to level. The severely off-circular shapes found by others during autopsies and computed tomography of the middle-aged and elderly were not detected in these children and adolescents. Under the circumstances of the study, there was little change in shape or size as the trachea passed from the neck into the chest, nor was there a consistent difference in tracheal shape between girls and boys.
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Osteodysplasty (Melnick-Needles syndrome, MNS), a severe bone dysplasia with presumed autosomal dominant inheritance, has now been described in 24 individuals, with a predominance of females (21:3). We report an affected woman who gave birth to a male infant with omphalocele, hypoplastic kidneys, and the skeletal changes of this disorder; he died soon after birth. Histologic studies of the calvaria and long bones showed normal maturational sequences, but suggest that remodeling was not normal. This is the second known instance of a male infant with omphalocele and this skeletal dysplasia born to a woman with MNS. We suggest that the gene for the MNS may also cause a syndrome of multiple abnormalities that can be lethal and that this more severe phenotype in males may account for the altered sex ratio among reported cases. Both X-linked dominant and autosomal-dominant sex-limited inheritance are feasible interpretations of the existing information.
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Explore the source record for details and available documents.