Harry Prystowsky

Fetal blood studies. XI. The effect of prophylactic oxygen on the oxygen pressure gradient between the maternal and fetal bloods of the human in normal and abnormal pregnancy.

IN PREVIOUS reports 1 • 2 estimates were made of the difference in the oxygen pressure of fetal and matemal blood as each passes through the human placenta. Such information not only enables one to assess quantitatively the normal limitation placed by the placenta upon the free movement of oxygen from one circulation to the other but also aids in evaluating the effect of abnormal and postmature pregnancy on oxygen transfer. Although these observations are of obvious importance, the clinician is primarily concerned with such questions as the following: (a) What measures may be taken to improve the position of the fetus when the limitation to oxygen transfer exceeds a normal range 1 (b) What can be done to forestall or mitigate intrauterine hypoxia~ These questions are understandable, for, in modern obstetrics, it is generally accepted that the threat of hypoxia is the greatest danger to which the fetus in utero is exposed; it is the most common cause of intrauterine death. Following up the important observations of Lund, 3 obstetricians have adopted the procedure of giving a patient oxygen when signs of fetal distress a})pear. During the past few years, in the Department of Obstetrics at the .Johns Hopkins Hospital, a large number of normal parturients have received oxygen 10 to 15 minutes before delivery; the administration of prophylactic oxygen to all parturients has been advocated by Eastman. His recommendation was based upon the general feeling that oxygen transfer to the fetus was enhanced, and this belief was based upon an increased oxygen saturation of umbilical vein blood. The interpretation of this latter finding is difficult for two main reasons. First, equally high values of umbilical vein oxygen saturation have been obtained in cases where no oxygen was given. Second, it is generally

A study of prolongation of obstetric anesthesia.

The clinical and biochemical effects of prolonging obstetric anesthesia were studied at cesarean section, using Pentothal, nitrous oxide, and succinylcholine. Mother, fetus, and newborn infant were evaluated. The average interval between the first injection of Pentothal and delivery was 36 minutes. Maternal respiratory gas and acid-base levels remained stable, as did uterine metabolism. Apgar scores were lower and more vigorous resuscitation was necessary with prolongation of anesthesia. The nitrous oxide concentrations in maternal, fetal, and newborn blood were significantly greater in this series of cases than in those delivered more rapidly. Effects of high nitrous oxide contents on newborn arterial oxygenation are discussed.

Fetal blood studies

Abstract The range of variation in the oxygen dissociation curves of blood of nonpregnant women and of pregnant women has been determined at the same pH—the latter falls within the range of normal nonpregnant individuals. The curves of fetal blood obtained at the end of gestation are to the left of the adult field. At 50 per cent saturation, the oxygen tension of maternal and fetal blood is of the order of 25.0 mm. and 19.0 mm. Hg, respectively—a difference of 6.0 mm. Hg.

OBSERVATIONS ON THE PLACENTAL EXCHANGE OF THE RESPIRATORY GASES IN PREGNANT WOMEN AT CESAREAN SECTION.

T H E H I G H oxygen capacity and low degree of saturation of the blood in the umbilical vessels of man observed by Eastman1 in 1930 led to the view that the blood of the fetus is exposed to a low oxygen tension while it is taking up that gas. Anselmino and Hoffman2 first suggested that the low tension was due to the resistance offered to the diffusion of oxygen by the tissue barrier of the placenta and to its intrinsic oxygen use. The fetus, in this view, appeared to be adjusted or acclimatized to an aspect of its environment it could not control, i.e., the low oxygen tension to which its blood is exposed in the placental capillaries. According to this view any reduction in the oxygen tension in the maternal placental capillaries might be expected to reduce the rate at which oxygen reaches the fetus and so to reduce its margin of safety.

Fetal blood studies: XIV. A comparative study of the oxygen dissociation curve of nonpregnant, pregnant, and fetal human blood

Abstract The range of variation in the oxygen dissociation curves of blood of nonpregnant women and of pregnant women has been determined at the same pH—the latter falls within the range of normal nonpregnant individuals. The curves of fetal blood obtained at the end of gestation are to the left of the adult field. At 50 per cent saturation, the oxygen tension of maternal and fetal blood is of the order of 25.0 mm. and 19.0 mm. Hg, respectively—a difference of 6.0 mm. Hg.

Effects of maternal metaboHc acidosis on the human fetus and newborn infant

The effects of maternal metabolic acidosis on fetal acid-base balance have been studied by comparing the P co 2 , pH, and bicarbonate levels in maternal, fetal, and newborn human blood plasma. Observations have been made without superimposed maternal acidosis during and following the slow infusion of ammonium chloride and during and following more rapid infusion. The results demonstrate that maternal metabolic acidosis is not necessarily accompanied by fetal or neonatal metabolic acidosis. Despite significant reductions in the maternal plasma HCO − 3 and pH, the fetal levels remain relatively unchanged. As the maternal pH falls, the usual transplacental pH gradient is virtually eliminated.

Alveolar PCO2 and PO2 in pregnant and nonpregnant women at high altitude

Abstract The alveolar P CO 2 of a group of pregnant women residing at an altitude of 14,500 feet was compared with that of a group of nonpregnant women residing at the same altitude. Pregnancy is associated with a hyperventilatory effect over and above the hyperventilation already existent on the basis of residence at altitude.

CARDIOVASCULAR EFFECTS OF RAPID INTRAVENOUS INJECTION OF SYNTHETIC OXYTOCIN DURING ELECTIVE CESAREAN SECTION.

Synthetic oxytocin injected rapidly, intravenously in 22 patients during elective cesarean section caused a decrease ill blood presslIre and an increase in heart rate. In 16 patients, heart rate, cardiac output, and stroke volume increased while mean arterial pressure and total peripheral resistance decreased. All changes were pronollllced, rapid in onset, and of short duration. No serious electrocardiographic changr;s were found. Repeat injeotion in 5 patients caused similar changes. The type of anesthesia did not appear to matter.

Oral progestational agents as a cause of Candida vaginitis

Abstract The effects of progestational agents on the vaginal flora have been studied in a group of women who had been taking a variety of oral contraceptives. Control observations have also been made. The results clearly demonstrate that in the former series there is an increased incidence of Candida vaginitis. Isolation of other organisms was affected by ingestion of contraceptive pills but not in a significant number of cases. Although not statistically valid we have the general feeling that sequential-type agents may not be as adverse as the combination type in regard to Candida vaginitis.

Candidial vaginitis associated with the use of oral progestational agents

A clinical study was undertaken to assess the association between the use of oral progestational agents and the incidence of candidial vaginitis. 96 unselected females, all in their reproductive years, who presented with symptoms of vaginitis at the Gynecology Clinic of the University of Florida Teaching Hospital were used in the study. 24 of the women had used oral progestational agents; the remaining 72 had not. Vaginal microbiological evaluation was carried out on all the women. 22 of the 24 women who had used oral progestagens showed heavy manifestations of Candida albicans. All of these women also showed Lactobacillus species and 50% showed Trichomonas vaginalis as well. Only 16.6% of the other group of women showed Candida albicans. Percentages of women in the nonusage group also exhibiting the other 2 pathogenic organisms were also markedly lower. So far, the literature has not noted a high incidence of monilial vaginitis associated with oral progestational use. Results of this study highlight the need for further research.