Influence of maternal oxygen administration on the term fetus before labor. [Correlation between the inspired fraction of oxygen, maternal partial oxygen pressure, and fetal partial oxygen pressure during cesarean section of normal pregnancies]. [Is oxygen therapy truly useful and necessary during elective cesarean section under spinal anesthesia?]. Effects of high inspired oxygen fraction during elective caesarean section under spinal anaesthesia on maternal and fetal oxygenation and lipid peroxidation. Oxygen transfer from mother to fetus during cesarean section under epidural anesthesia. Supplementary oxygen for elective Caesarean section under spinal anaesthesia: useful in prolonged uterine incision-to-delivery interval? Neonatal status in cesarean section under epidural anesthesia with supplementary oxygen. Supplementary oxygen administration for elective Caesarean section under spinal anaesthesia. Effects of maternal supplementary oxygen on the newborn for elective cesarean deliveries under spinal anesthesia.
Thirty-two healthy pregnant women at term who were to undergo cesarean section following epidural anesthesia were randomly assigned to receive preoperatively, by face mask, room air or oxygen for more than 10 minutes. Patients were kept at a left lateral tilt position of 15 degrees and were unaware which gas was administered. Oxygenation significantly increased (p less than 0.05) maternal PO2 to 283 mm Hg (SD 67). The cord vein PO2 of the group receiving oxygen was 34 mm Hg (SD 6), significantly higher (p less than 0.01) than the value of 26 mm Hg (SD 7) in the group receiving room air. The cord artery PO2 of the oxygen group was also significantly higher (p less than 0.05) at 20 mm Hg (SD 6) versus 15 mm Hg (SD 6). No other cord gas values were significantly different. There was no significant difference in the cord vein-artery PO2 differential. There was no significant difference in the infants' hematocrits determined at 4 hours of age in the two groups. All infants were in excellent condition (1-minute Apgar score greater than or equal to 8). Despite changes in pulmonary function, maternal oxygenation is maintained during obstetric regional blocks. But in those situations, the administration of supplementary oxygen to parturients is a common practice. Good fetal oxygenation is the main justification; however, this has not been proven. The objective of this randomized, prospective study was to test the hypothesis of whether maternal hyperoxia is correlated with an increase in fetal gasometric parameters in elective cesarean sections.
                Arterial blood gases of 20 parturients undergoing spinal block with different inspired fractions of oxygen were evaluated and correlated with fetal arterial blood gases.
                An increase in maternal inspired fraction of oxygen did not show any correlation with an increase of fetal partial oxygen pressure.
                Induction of maternal hyperoxia by the administration of supplementary oxygen did not increase fetal partial oxygen pressure. Fetal gasometric parameters did not change even when maternal parameters changed, induced by hyperoxia, during cesarean section under spinal block. To analyze maternal and fetal well-being with and without the application of oxygen therapy.
                Randomized trial of full-term parturients who had received prenatal care during pregnancy. The women were healthy and classified as ASA 1. They were scheduled for delivery by cesarean section under spinal anesthesia and randomized to 2 groups to breathe room air or air providing an inspired oxygen fraction of 40% through a face mask. We assessed the well-being of the neonate immediately after birth with the Apgar test and by measuring umbilical cord blood gases.
                One hundred thirty women were enrolled. Both groups were similar, with no differences in demographic or hemodynamic variables, time from uterine incision to fetal extraction, neonatal birth weight, presence of umbilical cord abnormalities, type of resuscitation required by the neonate, or Apgar score in the first or fifth minute. Oxygen saturation in maternal blood by pulse oximetry was higher after 10 minutes in the group of women who received supplemental oxygen through face masks. We also observed significant differences in umbilical cord arterial blood between the room air and supplemental oxygen groups, respectively, as follows: PaCO2, 51.14 mm Hg vs 54.33 mm Hg (P=.016); bicarbonate, 22.19 mEq L(-1) vs 23.23 mEq L(-1) (P=.012); lactate, 1.85 mmol L(-1) vs 1.64 mmol L(-1) (P=.038). The PO2 in venous blood also differed significantly: 25.53 mm Hg vs 28.13 mm Hg, respectively (P=033).
                Breathing supplemental oxygen or not during elective cesarean delivery of healthy parturients under spinal anesthesia does not have a significant effect on neonatal well-being. Oxygen supplementation is given routinely to parturients undergoing Caesarean section under regional anaesthesia. While the aim is to improve fetal oxygenation, inspiring a high oxygen fraction (FIO2) can also increase free radical activity and lipid peroxidation in both the mother and baby. In this prospective, randomized, double-blind study, we investigated the effect of high inspired oxygen fraction (FIO2) on maternal and fetal oxygenation and oxygen free radical activity in parturients having Caesarean section under spinal anaesthesia.
                Forty-four healthy parturients were randomized to breathe either 21% (air group) or 60% oxygen (oxygen group) intraoperatively via a ventimask. Maternal arterial blood was collected at 5-min intervals from baseline until delivery, and umbilical arterial and venous blood was collected at delivery. We measured blood gases and the products of lipid peroxidation (8-isoprostane, malondialdehyde (MDA), hydroperoxide (OHP)) and purine metabolites.
                At delivery, the oxygen group had greater maternal arterial PO2 [mean 30.0 (SD 6.3) vs 14.2 (1.9) kPa; mean difference 15.8 kPa, 95% confidence interval 12.9-18.7 kPa, P<0.001] and greater umbilical venous PO2 [4.8 (1.0) vs 4.0 (1.4) kPa; mean difference 0.8 kPa, 95% confidence interval 0.0-1.5 kPa, P=0.04] compared with the air group. Maternal and umbilical plasma concentrations of lipid peroxides (8-isoprostane, MDA, OHP) were greater in the oxygen group than in the air group (P<0.05).
                We conclude that breathing high FIO2 modestly increased fetal oxygenation but caused a concomitant increase in oxygen free radical activity in both mother and fetus. The correlation between maternal PaO2 levels and umbilical vein (UV) and umbilical artery (UA)PO2 levels was studied in 40 healthy patients undergoing elective cesarean sections under lumbar epidural anesthesia. Patients were divided into four equal groups. Each group inhaled oxygen at a FIO2 of 0.21, 0.47, 0.74 (in nitrogen), or 1.0. Maternal arterial samples and fetal UV and UA samples were collected at the time of delivery. Maternal PaO2 levels increased from 96 +/- 4 (1 SE) torr during exposure to to a FIO2 of 0.21 to 232 +/- 6, 312 +/- 16, and 423 +/- 6 torr while breathing FIO2 of 0.47, 0.74 and 1.0, respectively. UV PO2 levels increased from 28 +/- 1 to 36 +/- 1.5, 41 +/- 1.3 and 47 +/- 1.2 torr in the hyperoxic groups. UA PO2 levels increased from 15 +/- 0.7 to 19 +/- 0.8, 21 +/- 0.3, and 25 +/- 1.8 torr, respectively. Oxygen saturation and blood O2 contents increased in maternal and fetal blood. Maternal arterial, UV, and UA base excess values in the hyperoxic groups were significantly higher than in the normoxic groups. There was no difference in 1- or 5-minute Apgar scores between the normoxic and hyperoxic groups. It is concluded that maternal hyperoxia improves fetal oxygen stores and acid-base status during cesarean section under epidural anesthesia. The benefit of administering supplementary oxygen during elective Caesarean section under regional anaesthesia is controversial. It has been hypothesized that its use would improve fetal oxygenation in the event of a prolonged uterine incision-to-delivery (U-D) interval. Our aim was to test this hypothesis in a prospective, randomized, double-blinded, controlled study.
                We allocated randomly 204 women having elective Caesarean section under spinal anaesthesia to breathe 21, 40 or 60% oxygen. We recorded the U-D interval, umbilical arterial (UA) and venous (UV) blood gases and oxygen content and Apgar scores. Subgroup analysis was performed according to whether the U-D interval was prolonged (>180 s) or not.
                The U-D interval was <180 s in 159 patients and >180 s in 45 patients. There were no differences in UV or UA blood gases, oxygen content or Apgar scores between cases with and without a prolonged U-D interval. In cases without a prolonged U-D interval, administering 60% oxygen increased UV PO(2) (mean 4.3 (SD 1.1) vs 3.7 (1.0) kPa, P=0.003) and oxygen content (14.4 (3.3) vs 12.9 (2.7) ml dl(-1), P=0.007) compared with air. In cases with a prolonged U-D interval, administering 60% oxygen increased UV PO(2) (4.6 (0.6) vs 3.9 (0.8) kPa, P=0.019) compared with air but there was no difference in UV oxygen content. There was no increase in the UV PO(2) or oxygen content when 40% oxygen was administered compared with air.
                Supplementary oxygen did not increase fetal oxygenation in cases where the U-D interval was prolonged. Our data do not support the routine administration of supplementary oxygen during elective Caesarean section for this purpose. Simple O2 mask has been used in patient under regional anesthesia for increasing the FiO2, especially in the aged and the pregnant. The relationships between maternal FiO2 and umbilical arterial (UA) and venous (UV) PO2, PCO2, pH, and neonatal Apgar score were studied in 45 patients receiving Cesarean section under epidural anesthesia. 2% xylocaine 18-20 ml with adrenaline 1:200,000 was used to attain the sensory level of T-4. Patients were allocated randomly into three groups. Group I, acting as a control group, breath only room air during the course of anesthesia. Group II was breathing through a simple face mask with an oxygen inflow of 6L/min. Group III was breathing oxygen with a flow rate of 10L/min through a simple face mask. UA and UV blood samples were collected separately at the time of delivery for blood gas analysis. The 1-min, and 5-min Apgar scores were recorded also. Mean values of the UA blood samples for the 3 groups (Gp. I, Gp. II and Gp. III respectively) were: PO2--16.50 mmHg, 20.20 mmHg and 19.50 mmHg; PCO2--49.20 mmHg, 48.10 mmHg and 50.3 mmHg; pH--7.31, 7.30 and 7.30. Mean values of the UV blood samples for the 3 groups (Gp. I, Gp. II and Gp. III respectively) were: PO2--28.6 mmHg, 36.9 mmHg and 36.5 mmHg; PCO2--38.20 mmHg, 38.80 mmHg and 40.40 mmHg; pH--7.36, 7.36 and 7.34. There was a significant increase in UA and UV PO2 when using a simple O2 mask (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS) We investigated the necessity for administration of supplementary oxygen to mothers undergoing elective Caesarean section under spinal anaesthesia. Sixty-nine women undergoing elective Caesarean section were randomly allocated to one of three groups to be given either oxygen (40%) by facemask, air by facemask or oxygen at 2 l x min(-1) by nasal cannulae. Umbilical arterial and venous blood samples were taken and analysed immediately after delivery. The results showed that there were no significant differences in the umbilical arterial or venous pH, partial pressure of oxygen and partial pressure of carbon dioxide between any of the three groups. We also assessed the patient acceptability of oxygen administered by facemask vs. nasal cannulae should the need for supplementary oxygen arise. It was found that use of the facemask impeded communication. The aim of this investigation was to determine whether supplementary oxygen provided by either nasal cannula or face mask versus room air might affect fetal oxygenation during elective cesarean section under spinal anesthesia by assessing maternal and neonatal regional cerebral oxygenation (rSO(2)) with a cerebral oximeter.
                Ninety parturients were randomly allocated into three groups: two groups received 5 L/min oxygen by either nasal cannula (Group NC, n = 30) or face mask (Group FM, n = 30), respectively, and the third group was allowed to breathe room air (Group RA, n = 30). After maternal mean arterial pressure, heart rate and peripheral oxygen saturation had been monitored, rSO(2) was determined by cerebral oximeter. Umbilical artery (UA) and venous (UV) blood samples were collected for blood gas analysis. Neonatal rSO(2) and Apgar scores were recorded.
                The mean maternal rSO(2) which was recorded 3 and 5 min after administration of the spinal block in Group FM was lower than that of Group NC (p = 0.033 and 0.042, respectively). Neonatal rSO(2), UA pH, UV pH and UA base excess (BE) were lower in Group FM than in the other groups (p < 0.05). The Apgar score (1 min) in Group FM was lower than that of Group RA (p = 0.046).
                The effect of maternal supplementary oxygen on the newborn has been demonstrated by a cerebral oximeter monitor and supported by umbilical cord blood gas analysis and Apgar scores.