Respiratory Waves of Blood Pressure, with an Investigation of a Method for Making Continuous Blood Pressure Records in Man

Lewis/ in I9O8 , called attention " to the widespread misunderstanding of the relations which exist between respiration and blood pressure." He states that in books on the subject one finds usually only the results obtained by Einbrodt in the dog, and by Klemensiewicz in man. Essentially these consist of a rise of pressure during inspiration and a fall during expiration, although the rise during inspiration may be preceded by a fall of pressure, and the fall during expiration by a rise. An analysis of the literature, however, seems to indicate that there is little justification for these conclusions. Different investigators, 2 dealing with the same species of animal, have recorded diametrically opposed views, so that it seems unreasonable, in Lewis's opinion, to maintain the existence of but a single type of blood pressure wave. In the case of man, the results of different investigators are likewise discordant, although it would seem that the majority do not agree with Klemensiewicz, in that they find a pure fall of pressure in inspiration and a pure rise in expiration. The minority, nevertheless, find just the reverse to be the case in man. The variability of these results has been attributed to the use of faulty methods, and to differences in the type of respiration. In order to determine in man the effects of respiration upon