R--pulse wave timing: a technique for continuous cardiovascular monitoring in obstetrics--preliminary report.
A simple, noninvasive technique for continuous cardiovascular monitoring in obstetrics using R--pulse wave timing is described. This preliminary study suggests that different maternal heart rate/R pulse patterns are found in different clinical circumstances. A significant decrease in the R pulse interval occurred in the third trimester in both normal and diabetic women in the left lateral position when compared to the supine position. The R pulse intervals were all prolonged in the standing position in both gravid and nongravid women. During labor R pulse interval usually shortened during uterine contraction. Prolongation of R pulse interval was observed during thiopental injection, hypotension, and excessive bleeding at cesarean section. Exercise testing in healthy male subjects suggested that the change in R pulse interval becomes constant when the oxygen consumption rate reaches a plateau at 100% maximal work load. Further extensive clinical study appears worthwhile since it may add another dimension to cardiovascular monitoring and give an early indication of cardiovascular reserve.
D000773:Anesthesia, Obstetrical; D002585:Cesarean Section; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D010101:Oxygen Consumption; D005082:Physical Exertion; D049590:Postpartum Period; D011187:Posture; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000503:physiopathology; D011674:Pulse; D014590:Uterine Contraction