The Cerebral Blood Flow in Mitral Stenosis and Its Response to Carbon Dioxide

Ever since Kety and Schmidt (1948) showed that the cerebral blood flow (C.B.F.) of normal subjects would increase when carbon dioxide was inhaled, such inhalation has had obvious possibili- ties in the treatment of cerebral embolism. As it has not been known whether this increase would still occur when mitral stenosis, the commonest cause of cerebral embolism, was present, it was decided to measure the C.B.F. at rest and again during inhalation of 5 per cent carbon dioxide in 12 patients with this disease (Series 1). Since these patients were also being studied as to their suit- ability for surgical treatment the opportunity was taken to compare the C.B.F. with the clinical status of the patients and with the hlmodynamic findings obtained by cardiac catheterization both at rest and during exercise. This report includes in addition estimations of the C.B.F. at rest of 13 other subjects who suffered from mitral stenosis and were having cardiac catheterization done (Series 2) and of 6 student volunteers who acted as controls (Series 3). The combined series show how the resting C.B.F. of patients with mitral stenosis differs from the normal. SUBJECTS, METHODS, AND PROCEDURE Details of the 12 subjects of Series 1 are given in Table None were in congestive heart failure or suffering from active rheumatism. The 13 subjects whose C.B.F. are given who did not inhale CO2 include six from a series previously reported Six of the other seven patients were from a series not previously published and had been given a dosage of nitroglycerine which proved to be without influence on the C.B.F.; these latter six may be regarded as controls for the reproducibility of the method. None of the subjects in Series 2 or Series 3 were given morphine at any stage of their C.B.F. estimations.