Experiments on the Pulmonary Edema of Nervous Origin (I) : Pulmonary Findings and Hemodynamic Changes Associated with Preoptic or Hypohalamic Lesions

It has been known that the pulmonary edema is frequently accompanied by central nervous disorders. This state frequently found in autopsy. It has been assumed that the condition was due to an increased permeability of the pulmonary capillary caused by the disturbed innervation of cardiovascular region. The author has attempted to clarify the mechanism of the pulmonary edema by experimentally inducing preoptic lesions.Method A central nervous lesion was produced by the electric coagulation in rabbits and dogs, whose brains were fixed and lesions were identified later by the microscopic study. Lung tissues were microscopically observed and findings were classified by Jordan's Table ; the pulmonary edema was also evaluated in ways previously reported by this author. Lung body ratio was calculated by the weight of lung and that of body. Systemic blood pressure was measured directly from the femoral artery through the canula connected with a mercury manometer. Wedge pressure was measured optically by the venous catheterization. Cardiac output was estimated by the dyedilution method. Spinal cord was cut surgically at the level of Cerval cord I-III, and bilateral vagal nerves at the cevical level, both under the artificial respiration. Results I. Pulmonary findings and systemic blood pressure in diencephalic lesions in rabbits. 1) Group of preoptic lesion Animals showed excitement after operation, and systemic blood pressure was elevated at first abruptly and fell gradually after a few minutes resulting in death. The existence of pulmonary edema was definitely proved both macroscopically and microscopically : there was an intra-alveolar edema accompanied by capillary congestion. Lung body ratio was high as compared with the normal. Pulmonary edema was found in 15 (75%) of 20 cases, but no correlation could be obtained between the grade of the pulmonary edema and the extent of preoptic lesion. 2) Group of hypothalamic lesion Systemic blood pressure has shown only slight fluctuation and neither macroscopically nor microscopically were any pathologic finding obtainable. Lung body ratio was also within normal ranges. In this group, pulmonary edema was found in only one (7%) of 15 cases. II. Role of the spinal nervous system and vagal nerves in pulmonary edema induced by the preoptic lesion. 1) Group of spinal transection As cervical spinal transection has been followed by a sudden fall of the blood pressure, a preoptic lesion was produced after the change of blood pressure was recovered by the transfusion of dextran or P.V.P. No pathological findings occurred in lungs and systemic blood pressure this group. 2) Group of the vagotomy Systemic blood pressure fell transiently, and recovered rather quickly. When a preoptic lesion was produced thereafter, blood pressure was abruptly elevated and began to fall in a few minutes ; most of the animals died. The lungs have shown the same degree of pulmonory edema as in the group of the preoptic lesion. III. Hemodynamic changes caused by preoptic or hypothalamic lesions in dogs. 1) Group of preoptic lesions. Pulmonary edema was found in 75% of this group. Elevation of systemic blood pressure (40±15 mmHg), elevation of wedge pressure (41±13 mmHg) and decrease of cardiac output (26±6%) were observed in these cases. 2) Group of hypothalamic lesions. The lungs showed no pathological findings, and elevation of systemic (12±5 mmHg) and wedge pressure (7±3 mmHg), and decrease of cardiac output (12±6%) were not so severe in degree as compared with the group of the preoptic lesion. Discussion Although anatomically the preoptic area belongs to the telencephalon, functionally not only this area but also the hypothalamus are closely associated with the autonomic nervous center. But it has not been proved whether it behaves the sympathetically or parasympathetically. [the rest omitted]