Fetal Oxygen Saturation Monitoring Research Articles

Validation of a Novel Transabdominal Fetal Oximeter in a Hypoxic Fetal Lamb Model.

Current intrapartum fetal oxygen saturation (SaO2) monitoring methodologies are limited, mostly consisting of fetal heart rate monitoring which is a poor predictor of fetal hypoxia. A newly developed transabdominal fetal oximeter (TFO) may be able to determine fetal SaO2 non-invasively. This study is to validate a novel TFO in determining fetal SaO2 in a hypoxic fetal lamb model. Fetal hypoxia was induced in at-term pregnant ewe by placing an aortic occlusion balloon infrarenally and inflating it in a stepwise fashion to decrease blood flow to the uterine artery. The inflation was held at each step for 10min, and fetal arterial blood gases (ABGs) were intermittently recorded from the fetal carotid artery. The balloon catheter was deflated when fetal SaO2 fell below 15%, and the fetus was recovered. A total of three desaturation experiments were performed. The average fetal SpO2 reported by the TFO was derived at each hypoxic level and correlated with the ABG measures. Fetal SaO2 from the ABGs ranged from 10.5 to 66%. The TFO SpO2 correlated with the ABG fetal SaO2 (r-squared = 0.856) with no significant differences (p> 0.5). The fetal SpO2 measurements from TFO were significantly different than the maternal SpO2 (p< 0.01), which suggests that the transcutaneous measurements are penetrating through the maternal abdomen sufficiently and are expressing the underlying fetal tissue physiology. The recently developed TFO system was able to non-invasively report the fetal SpO2, which showed strong correlation with ABG measures and showed no significant differences.

Fetal Pulse Oximetry and Cesarean Delivery

ABSTRACT More than 5 years ago the Food and Drug Administration approved, conditionally, the OxiFirst Fetal Oxygen Saturation Monitoring System as an adjunct to electronic fetal monitoring. The goal of monitoring was to gain more knowledge of the condition of the fetus by continuously monitoring oxygen saturation when there is a nonreassuring fetal heart rate pattern. The sensor is inserted through the dilated cervix following membrane rupture, and positioned against the fetal face. This randomized trial, conducted at 14 university-based clinical centers, was designed as a means of learning whether adjunctive fetal oximetry lessens the need for cesarean delivery. Participants were nulliparous women with a singleton fetus in cephalic presentation at 36 or more weeks' gestation. The 5341 women in the study were randomized to either “open” fetal pulse oximetry with oxygen saturation values displayed to the clinician, or “masked” oximetry in which the results were hidden. Overall rates of cesarean delivery were 26.3% for the open group and 27.5% for masked monitoring, not a significant difference. The respective operative delivery rates were 7.1% and 7.9% for a nonreassuring fetal heart rate pattern; and 18.6% and 19.2% for dystocia, Findings were similar for the 2168 women in whom a nonreassuring fetal heart rate pattern was identified before randomization. There were no significant differences between the open and masked groups in the rates of forceps or vacuum-assisted delivery, even after excluding women who had labor induced. The relative risk of cesarean delivery associated with knowing the fetal oxygen saturation was 0.96 (95% confidence interval, 0.87–1.04). Neither maternal nor infant complications differed significantly in incidence between the study groups. The sensitivity, specificity, positive predictive value, and negative predictive value of a nonreassuring fetal heart rate pattern for low oxygen saturation (defined as less than 30% for 2 consecutive minutes) were, respectively, 87%, 19.5%, 35%, and 75%. One-fourth of fetuses with a normal heart rate pattern exhibited low oxygen saturation. This large-scale study failed to demonstrate that knowledge of intrapartum fetal oxygen saturation significantly lowers the rate of cesarean delivery or improves infant outcomes. The findings emphasize the need to rigorously evaluate new technologies.

The influence of vacuum extractor on fetal oxygenation and newborn status.

The aim of this study was to determine the effects of vacuum extractor assisted delivery on fetal oxygenation and acid-base balance. Sixty-one women were enrolled in the present study. The subjects were divided into two groups. Group A, consisting of 39 women, had normal vaginal deliveries. Group B, consisting of 22 women, underwent a vacuum extractor assisted vaginal delivery. Fetal arterial oxygen saturation (SpO2) monitoring was used in all women after full cervical dilatation. After delivery, umbilical artery pH, pCO2, pO2 and base deficit (BDecf) levels were determined in all neonates. The mean FSpO2 value in Group A was 51.53+/-5.87% and in Group B 48.03+/-6.39% (p<0.03). The mean cord pH value in fetuses of Group A was 7.26+/-0.05, and in Group B 7.17+/-0.09. There was also a significant difference between the two groups with regards to mean pO2, pCO2 and BDecf values. Vacuum assisted vaginal delivery was associated with lower fetal arterial oxygen saturation levels as well as lower cord blood pH values compared to those seen after unassisted vaginal delivery. Although decreased, however, the above parameters remained within normal ranges.

A new assessment tool: fetal oxygen saturation monitoring.

Pulse oximetry technology enables clinicians to obtain intrauterine fetal oxygen saturation levels.

Fetal oxygen saturation monitoring during labor: Implications for perinatal risk management

Journal of Healthcare Risk ManagementVolume 21, Issue 1 p. 17-27 Article Fetal oxygen saturation monitoring during labor: Implications for perinatal risk management Kathleen Rice Simpson PhD, RNC, FAAN, Kathleen Rice Simpson PhD, RNC, FAAN Perinatal Clinical Nurse Specialist Women's and Children's Care Center St. John's Mercy Medical Center St. Louis, MOSearch for more papers by this author Kathleen Rice Simpson PhD, RNC, FAAN, Kathleen Rice Simpson PhD, RNC, FAAN Perinatal Clinical Nurse Specialist Women's and Children's Care Center St. John's Mercy Medical Center St. Louis, MOSearch for more papers by this author First published: 23 July 2009 https://doi.org/10.1002/jhrm.5600210105Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume21, Issue1Winter 2001Pages 17-27 RelatedInformation

Fetal Oxygen Saturation Monitoring: Using This New Technology for Fetal Assessment During Labor

Fetal Oxygen Saturation Monitoring: Using This New Technology for Fetal Assessment During Labor

Intrapartum fetal oxygen saturation monitoring in a busy labour ward

Objective: To measure the ease of use of a fetal pulse oximeter in a busy labour ward. Design: Descriptive study in the Labour Ward, National University Hospital, Singapore, involving 145 labouring women with singleton pregnancies, and fetuses in cephalic presentation, with cervical dilatation >2 cm and amniotic membranes ruptured. Results: Placement was comfortable. Oxygen saturation (S pO 2) readings were obtained in 127 women (87.5%). Adequate readings were obtained a median of 69% of the time the transducer was in situ. S pO 2 values in the last 10 min prior to delivery correlated poorly with parameters of neonatal outcome. Conclusion: The Nellcor N-400 fetal pulse oximeter and FS14 fetal sensor is a feasible method of intrapartum fetal monitoring in a busy labour ward and is acceptable to labouring women.

Fetal oxygen saturation monitoring during labor.

Since the discovery of the ability to detect fetal heart tones in the 1980s, there has been ongoing research about how to interpret the meaning of these data. Fetal pulse oximetry, also known as fetal oxygen saturation monitoring, is a new method of assessing fetal status during labor that is under investigation in the United States. The article discusses limitations of current methods of fetal assessment, the potential benefits and limitations of fetal oxygen saturation monitoring, and future possibilities for fetal assessment during labor.

Ongoing Clinical Research Explores Partnering New Method with EFM

A new method of assessing fetal status during labor— fetal oxygen saturation (Fsa0 2 ) monitoring via fetal pulse oximetry—may provide more objective data and give those who care for women during labor more accurate information about fetal oxygen status. This technology is currently under investigation in a multicenter randomized U.S. Food and Drug Administration‐approved clinical trial (Dildy, Clark, & Loucks, 1996; Lien & Garite, 1997).

Intrapartum fetal oxygen saturation monitoring in congenital fetal heart block.

Conventional intrapartum electronic fetal heart rate monitoring is not informative in certain fetal conditions because the electronically-monitored fetal heart rate pattern is uninterpretable in terms of reflecting fetal normoxia. Such fetal conditions include various cardiac dysrrhythmias and some central nervous system abnormalities. Difficulties with intrapartum fetal welfare surveillance in such conditions often lead to operative delivery as a precautionary measure. We report 2 cases of intrapartum fetal oxygen saturation monitoring in the presence of congenital complete heart block (CCHB), using the Nellcor N400/FS14 oxygen saturation monitoring system. Mean intrapartum fetal oxygen saturation (FSpO2) was 32% (SEM +/- 1%) in the first case and 48% (SEM +/- 0.3%) in the second case. In both cases, vaginal delivery of otherwise healthy infants was achieved. Fetal pulse oximetry is a promising new technique which directly measures fetal oxygenation without reference to fetal heart rate patterns. It may assist in the intrapartum fetal welfare assessment in conditions such as complete heart block, thereby helping to avoid otherwise unnecessary operative delivery.

Fetal oxygen saturation monitoring in labour: an analysis of 118 cases.

Fetal oxygen saturation (FSpO2) was recorded during labour to determine the relationship between FSpO2 and indicators of fetal well-being, including umbilical blood gases, xanthine (X), hypoxanthine (Hx) and Apgar scores. This is one of the largest reported series of fetal pulse oximetry, with 118 fetuses monitored for over 329 hours. Mean FSpO2 for all cases was 46.9% (SD = 9.1%). There was no correlation between FSpO2 during the last 10 minutes of monitoring and arterial pH, Hx or X. A mean FSpO2 > or = 30% was associated with a 5 minute Apgar score of > or = 7 in the majority of cases. One fetus had a mean FSpO2 < 30% during the final 10 minutes of monitoring and an umbilical arterial pH < 7.20, while there were 10 fetuses with an umbilical arterial pH < 7.20, and mean FSpO2 > or = 30%. As these numbers are small, a larger series is necessary to further characterize the small number of fetuses who are significantly hypoxic.

Prediction of umbilical artery base excess by intrapartum fetal oxygen saturation monitoring

OBJECTIVE: Our purpose was to evaluate the predictive value of intrapartum fetal oxygen saturation as monitored by reflectance pulse oximetry (Spo 2) for metabolic acidosis at birth. STUDY DESIGN: An observational study was carried out on intrapartum patients at ≥35 weeks' gestation having either a nonreassuring fetal heart rate pattern, intrauterine growth restriction, or thick meconium. Fetal oxygen saturation monitoring was performed with use of the Nellcor N-400 monitor and the FS-14 fetal oxygen sensor. Mean values of Spo 2 from the last 30 minutes of monitoring were correlated with umbilical artery base excess and pH at birth, with use of regression analysis, whereas the prediction of acidosis by Spo 2 at different thresholds was tested with use of receiver-operator characteristic curve calculations. RESULTS: Fifty-four patients met the criteria for data analysis, with a mean Spo 2 monitoring time of 150 ± 124 minutes (SD) and a mean signal loss of 30% ± 20%. Mean fetal Spo 2 for the last 30 minutes of monitoring averaged 42.1% ± 9.9% and, for individual patient studies, correlated significantly with calculated oxygen saturation in the umbilical vein ( r = 0.52, p < 0.001) and in the umbilical artery ( r = 0.34, p = 0.02) as measured at birth. However, the correlation with umbilical artery base excess values at birth was somewhat weaker ( r = 0.30, p < 0.05), as was the correlation with umbilical artery pH values ( r = 0.26, p = 0.05). Receiver-operator characteristic curve calculations were all nonsignificant when Spo 2 from the last 30 minutes of monitoring was used as a diagnostic test for predicting acidosis at birth. CONCLUSIONS: Intrapartum fetal Spo 2 as monitored in the current study was of limited use as a diagnostic test for predicting acidosis at birth, regardless of the Spo 2 cutoff value used. (Am J Obstet Gynecol 1997;177:775-9.)

Current status of the multicenter randomized clinical trial on fetal oxygen saturation monitoring in the United States

Current clinical methods of intrapartum fetal assessment are sensitive but poorly specific in detecting fetal compromise during labor. These limitations have substantially contributed to the escalating cesarean section rate which occurred in the US during the last several decades. Experimental and clinical research efforts directed towards application of the oxygen saturation monitor (pulse oximeter) to intrapartum fetal assessment have produced encouraging results. If this new method of fetal assessment is to enter the clinical arena, safety and efficacy issues must first be properly evaluated via randomized clinical trials. The purpose of this report is to describe the design of a multicenter randomized clinical trial of intrapartum fetal oxygen saturation monitoring recently begun in the US. Specific aspects of the trial, including purpose, study design, sample size estimates, control and test groups, inclusion and exclusion criteria, fetal heart rate classification, definition of normal fetal arterial oxygen saturation (Spo2), clinical management protocol, and assessment of maternal–fetal outcomes will be addressed.© 1997 Elsevier Science Ireland Ltd.

Should C-section be applied to fetal arrhythmia?

Objective: To investigate the efficacy of fetal arterial oxygen saturation (Spo2) monitoring in cases of fetal arrhythmia. Study Design: Continuous fetal Spo2 was obtained by infrared pulse oximetry (Nellcor Puritan Bennett Inc.). The relationship between Spo2 and FHR pattern was studied in 47 cases. Then three cases of congenital complete A–V block and two cases of supraventricular tachyarrhythmia were prospectively managed by Spo2 monitoring during labor. Results: Whenever the FHR was confirmed, the range of Spo2 was stable between 40 and 80%. Although a variation in Spo2 values were noted during decelerative patterns, a more acidic tendency was found in cases where Spo2 was below 40% prior to delivery. Spo2 values of all five cases of fetal arrhythmia were stable between 40 and 80% and safe vaginal delivery proved to be possible. Conclusions: Fetal Spo2 monitoring seemed to be a useful method to evaluate fetal oxygenation during labor in cases of fetal arrhythmia.© 1997 Elsevier Science Ireland Ltd.

Prediction of umbilical artery base excess by intrapartum fetal oxygen saturation monitoring

Prediction of umbilical artery base excess by intrapartum fetal oxygen saturation monitoring

The relationship between oxygen saturation and pH in umbilical blood: Implications for intrapartum fetal oxygen saturation monitoring

OBJECTIVE: Our purpose was to evaluate the relationship between umbilical arterial blood oxygen saturation determined by hemoximetry (Sao2) and umbilical arterial blood pH and base excess determined by blood gas analysis to establish a ″critical threshold” for fetal preductal arterial oxygen saturation determined by reflectance pulse oximetry (Spo2). STUDY DESIGN: Umbilical artery and vein blood specimens were obtained at delivery. Blood gas analysis and hemoximetry were performed. Polynomial regression analysis and receiver-operator characteristic curves were calculated for umbilical arterial blood Sao2 and theoretic preductal arterial blood Sao2 versus umbilical arterial blood pH and base excess. RESULTS: A total of 1101 paired umbilical artery and vein specimens were obtained. When the umbilical arterial blood Sao2 was ≥30%, umbilical arterial blood pH was ≥7.13 in 99.0% (388/392) of cases and <7.13 in 1.0% (4/392) of cases. When umbilical arterial blood Sao2 was <30%, umbilical arterial blood pH was ≥7.13 in 91.4% (648/709) of cases and <7.13 in 8.6% (61/709) of cases. CONCLUSIONS: From these analyses, it appears that an Spo2 cutoff value of 30% would be reasonable in clinical trials of intrapartum fetal pulse oximetry. (Am J Obstet Gynecol 1996;175:682-7.)

Intrapartum fetal pulse oximetry: Past, present, and future

Oxygen saturation monitoring (pulse oximetry) has markedly improved medical care in many fields, including anesthesiology, critical care, and newborn intensive care. In obstetrics, fetal heart rate monitoring remains the standard for intrapartum assessment of fetal well-being. Fetal heart rate monitoring is sensitive but nonspecific for detecting fetal compromise. Additional clinical information is needed to discern those fetuses not at risk for development of intrapartum acidosis to avoid unnecessary intervention. Fetal oxygen saturation monitoring is a new technique currently under development. This article reviews the evolution of intrapartum fetal oxygen saturation monitoring and proposes directions for future investigation. (Am J Obstet Gynecol 1996;175:1-9.)

Women's evaluations of their experience with fetal intrapartum oxygen saturation monitoring and participation in a research project

Objective: to evaluate women's perceptions of their participation in a research project in labour and their experience with fetal oxygen saturation monitoring. Design: survey using a questionnaire of women's ratings of ten aspects of their experience with the project. Setting: Royal Women's Hospital, Brisbane, Australia. Participants: women who had participated in clinical observational studies of fetal intrapartum oxygen saturation monitoring. Findings: 78 questionnaires were distributed and 77 returned. Overall, women evaluated their participation in this research project favourably, in terms of both their involvement in the research study and the use of fetal oxygen saturation monitoring. Several women commented that they appreciated the additional support they received from the research midwife. Key conclusions: responses indicated that the women surveyed appreciated the opportunity to participate in research, were not averse to this new technology, and benefited from the perceived additional human contact and support they received. The high response rate to the questionnaire indicates that childbearing women are willing to be included in assessing the appropriateness of new birth technologies that may affect the well-being of women and babies in the future.

Human fetal intrapartum oxygen saturation monitoring: Agreement between readings from two sensors on the same fetus

OBJECTIVE: Our purpose was to assess the level of agreement between oxygen saturation values obtained from two identical sensors used on different sides of the face of the same human fetus during labor. STUDY DESIGN: Two identical fetal pulse oximeter sensors were placed on 12 fetuses during uncomplicated labor at ≤38 weeks' gestation. Oxygen saturation, fetal heart rate, and uterine activity were recorded. The agreement between synchronous values of oxygen saturation was assessed by calculating the mean difference and SD of the difference. The SD of a single sensor was estimated as the SD of the difference divided by the square root of 2. RESULTS: The mean oxygen saturation value returned from one sensor was 49.2% and from the other 49.9%; the mean difference was −0.7%. The SD of the difference was 7.5%, and the 95% limits (±2 SDs of the difference) were −15.5% to 14.1%. The SD from a single sensor was estimated as 5.3%. CONCLUSIONS: There was no clinically significant difference between the oxygen saturation values returned from two identical sensors on the one fetus. The magnitude of the SD from a single sensor must be taken into account when an arbitrary “cutoff” or “action” oxygen saturation value in a clinical setting or trial is defined. (AM J OBSTET GYNECOL 1996;174:1594-8.)

Reflectance pulse oximetry in neonates

Objective: To test the feasibility and reliability in neonates of an in-house reflectance pulse oximetry (RPOX) system as an alternative method of non-invasive oxygen saturation monitoring when transmission pulse oximetry (TPOX) cannot be used, as in fetal scalp oxygen saturation monitoring during delivery. Study Design: The study population consisted of 31 intensive care neonates. The RPOX sensor was attached by suction to the forehead, cheek, occiput and back; recordings were under simultaneous TPOX control. Results: There was close agreement between RPOX and TPOX oxygen saturation and heart rate values, even in periodic breathing. RPOX signals from the back were unreliable because of breathing artifacts. Differences in mean absolute RPOX and TPOX oxygen saturation values were due to different calibrations. Both systems were equally sensitive to motion artifacts. Conclusion: As a feasible and reliable method of non-invasive oxygen saturation monitoring in neonates, RPOX has potential applications in fetal scalp monitoring.