Electronic fetal monitoring and clinical practice. A survey of obstetric opinion

The 90 plus: longevity and COVID-19 survival

The world population is getting older and studies aiming to enhance our comprehension of the underlying mechanisms responsible for health span are of utmost interest for longevity and as a measure for health care. In this review, we summarized previous genetic association studies (GWAS) and next-generation sequencing (NGS) of elderly cohorts. We also present the updated hypothesis for the aging process, together with the factors associated with healthy aging. We discuss the relevance of studying older individuals and build databanks to characterize the presence and resistance against late-onset disorders. The identification of about 2 million novel variants in our cohort of more than 1000 elderly Brazilians illustrates the importance of studying highly admixed populations of non-European ancestry. Finally, the ascertainment of nonagenarians and particularly of centenarians who were recovered from COVID-19 or remained asymptomatic opens new avenues of research aiming to enhance our comprehension of biological mechanisms associated with resistance against pathogens.

Errors and pitfalls in reading the cardiotocographic tracing

Reading of fetal heart rate (FHR) tracing during labor remains one of the most controversial and problematic issues in Obstetrics. The incorrect interpretation of CTG can be due to errors and pitfalls. Some common errors are related to the incorrect use of oxytocin, specifically the failure to recognize tachysystole, to correct it and to use oxytocin to accelerate labor when the fetal heart rate tracing is not reassuring. A common error is also the incorrect interpretation of deceleration that leads to unnecessary and often dangerous interventions, despite the clarification of the significance of decelerations, which in themselves are not a sign of impending acidosis, except when they are accompanied by loss of variability. Another potential error that can be identified as a pitfall is the transition from fetal to maternal heart rate (MHR) recording. The misidentification of MHR as FHR can potentially mask pathological FHR traces, appearing as a falsely reassuring trace.

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 (SpO2) readings were obtained in 127 women (87.5%). Adequate readings were obtained a median of 69% of the time the transducer was in situ. SpO2 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.

Stochastic technology, production organization and costs

Using a model including patients, physicians, insurers and uncertain diagnostic technology, the optimal cesarean rate is derived from preferences, technology and the incidence rate, when the choice of insured patients is constrained only by technology. Uncertain diagnosis produces unnecessary cesareans and unsafe vaginal births. Technical progress can lead to more cesareans and higher costs. Joint production of goods and bads and collective payments require incentive compatible pricing schemes, different from RBRVS. Equilibrium outcomes of HMOs and free-for-service organizations are identical. However, implementable incentive schemes involve additional costs. Efficiency requires insurers, and not providers, to be liable for malpractice claims.

Differences among obstetricians in caesarean section rates

This retrospective study examined the Caesarean section rates of 15 obstetricians at 1 hospital delivering 5,559 nulliparas with a single cephalic baby of birth-weight > or = 2,500 g. There was a wide variation in obstetricians' Caesarean rates, whether considering all their deliveries (5.5% to 20.1%), deliveries of their own patients (8.9% to 28.2%), or deliveries of their colleagues' patients (4.5% to 17.9%). There was no relation between Caesarean rates and perinatal outcome. The different Caesarean section rates among the obstetricians could not be explained by institutional factors, physician convenience, patient differences, or self-serving economic incentives.

On intrapartum fetal monitoring

The currently advised conduct for intrapartum surveillance of the fetus is either intermittent auscultation of continuous electronic monitoring, depending on the physician's preference. This applies to all, normal or high-risk, conditions. The bases for this recommendation, a number of controlled studies comparing the two methods, showed no better neonatal outcomes and increased cesarean section rates with electronic fetal monitoring. A review of the works pertaining to fetal development of cardiovascular and central nervous systems and their response to various pathophysiologic conditions (in animals and humans) was carried out in an effort to find an explanation for this apparently uncongruous position. It was found that fetal responses to seemingly comparable conditions are radically different depending on age of gestation. Many authors have pointed this out for the human fetus. However, for interpretation of electronic fetal monitoring in labor, various standard, nondescriptive, confusing words are used to imply the need for rapid intervention. The complete lack of uniform interpretation has been shown in studies comparing interobserver and intraobserver variations. This may be the consequence of poor or superficial teaching of a tool that requires much study and hard work for useful application. The inescapable conclusion is unpleasant but inevitable: to use electronic fetal monitoring properly it is necessary to start a new learning of the physiology of the fetus, its changing evolution as pregnancy advances, its different responses under stress or distress, and the various ways these are represented in electronic fetal monitoring tracings. These efforts take dedication and time spent in labor suites collating tracings with neonatal condition. Only by doing this will it be possible to assist the laboring patients with a useful tool that, so far, has not been adequately applied because of insufficient understanding.

Uncertain value of electronic fetal monitoring in predicting cerebral palsy

BACKGROUND

Electronic monitoring of the fetal heart rate is commonly performed, in part to detect hypoxia during delivery that may result in brain injury. It is not know whether specific abnormalities on electronic fetal monitoring are related to the risk of cerebral palsy.

METHODS

Among 155,636 children born from 1983 through 1985 in four California counties, we identified singleton infants with birth weights of at least 2500 g who survived to three years of age and had moderate or severe cerebral palsy. The children with cerebral palsy were compared with randomly selected control children with respect to characteristics noted in the birth records.

RESULTS

Seventy-eight of 95 children with cerebral palsy and 300 of 378 controls underwent intrapartum fetal monitoring. Characteristics found to be associated with an increased risk of cerebral palsy were multiple late decelerations in the heart rate, commonly defined as slowing of the heart rate well after the onset of uterine contractions (odds ratio, 3.9; 95 percent confidence interval, 1.7 to 9.3), and decreased beat-to-beat variability of the heart rate (odds ratio, 2.7; 95 percent confidence interval, 1.1 to 5.8); there was no association between the highest or lowest fetal heart rate recorded for each child and the risk of cerebral palsy. Even after adjustment for other risk factors, the association of abnormalities on fetal monitoring with an increased risk of cerebral palsy persisted (adjusted odds ratio, 2.7; 95 percent confidence interval, 1.4 to 5.4). The 21 children with cerebral palsy who had multiple late decelerations or decreased variability in heart rate on fetal monitoring represented only 0.19 percent of singleton infants with birth weights of 2500 g or more who had these fetal-monitoring findings, for a false positive rate of 99.8 percent.

CONCLUSIONS

Specific abnormal findings on electronic monitoring of the fetal heart rate were associated with an increased risk of cerebral palsy. However, the false positive rate was extremely high. Since cesarean section is often performed when such abnormalities are noted and is associated with risk to the mother, our findings arouse concern that, if these indications were widely used, many cesarean sections would be performed without benefit and with the potential for harm.

How useful is intrapartum electronic fetal heart rate monitoring?

It is essential for an obstetric anesthesiologist to be aware of the fetal status before undertaking care of the laboring mother. In the last 20 years electronic fetal monitoring has been the most widely used technique of evaluating the fetus in labor. Recently however, the ability to predict or improve fetal outcome using traditional interpretation has been questioned. This review presents a summary of the current technology and interpretation of intrapartum electronic fetal monitoring, as well as a discussion of its limitations and some of the developments in this field which may help improve the accuracy of fetal assessment. The new developments in fetal monitoring discussed in this article are computerized assessment of fetal heart tracings, heart rate variability analysis, fetal electrocardiogram waveform analysis, abdominal detection of fetal ECG, fetal scalp oxygen saturation, fetal pH sampling and transcutaneous oxygen and carbon dioxide measurement.

Intrapartum cardiotocography and the expert witness

Fetal heart rate changes occur in the majority of labours and correlate poorly with perinatal outcome and subsequent neurological development. Obstetricians giving expert evidence related to the interpretation of intrapartum cardiotocographs are advised to exercise caution when expressing their opinions.

Management decisions after nonstress testing

Evaluation of patient management after the utilization of a specific diagnostic test has been difficult to interpret from retrospective studies. Specifically, the impact of the interpretation of the diagnostic study, the environment where the test is performed, and the biases of the physician have been difficult to separate. In this study, agreement on first-choice management decisions by a national sample of obstetricians blinded to specific clinical information, based on interpretations of five nonstress tests, was low (kappa = 0.24 +/- 0.02). The response "evaluate for delivery" was significantly different between "reactive" and "nonreactive" interpretations. There was better management agreement among those respondents with more experience with nonstress testing; those from larger hospitals; and those who practiced at universities, HMOs, and military hospitals. The attitudes of individual respondents as measured by the first-choice goals of the test did not significantly influence overall management agreement. Reliability of management was less among physicians aged 50-59 years. There was no obvious national consensus regarding management following nonstress testing.

Intermediate, indeterminate, and uninterpretable diagnostic test results

Diagnostic tests do not always yield positive or negative results; sometimes the results are intermediate, indeterminate, or uninterpretable. No consensus exists for the incorporation of such results into data assessment. Conventional Bayesian analysis leads investigators to either exclude patients with non-positive, non-negative results from their studies or categorize such results into inappropriate cells of the standard four-cell decision matrix. The authors propose a standardized method for reporting results in studies dealing with diagnostic test use and discuss how researchers should expand the four-cell matrix to six cells when non-positive, non-negative results occur. They suggest that the six-cell matrix with new operational definitions of sensitivity, specificity, likelihood ratios, and test yield should be adopted routinely. In addition, they define the different types of non-positive, non-negative results and demonstrate how clinicians can use tree-structured decision analysis from the six-cell matrix. While their method does not solve all problems posed by non-positive, non-negative results, it does suggest a standard method for reporting these results and utilizing all the data in decision making.

Interpretation of nonstress tests

Five nonstress tests were interpreted by a national sample of obstetricians blinded to specific patient clinical data. The 169 questionnaires suitable for analysis showed that the reliability of the test interpretation, as measured by the kappa statistic, decreased with increasing number of categories of interpretation. Kappa values for two, three, and five categories of interpretation were 0.60, 0.39, and 0.36, respectively. The middle values in the three- and five-category methods of interpretation had very low levels of reliability. Kappa values as related to the age of the respondent or measurements of experience showed relatively small changes in reliability of interpretation.

Factors involved in the interpretation of fetal monitor tracings

In order to study how physicians choose to use electronic fetal monitoring and interpret tracings, we administered a questionnaire to which 107 practicing obstetricians and 11 experts in electronic fetal monitoring responded. Sixty-one (57%) of the respondents monitored more than half of their deliveries (high users). In comparison to the less frequent users of electronic fetal monitoring (low users), they showed more positive attitudes toward electronic fetal monitoring and were nearly always more likely to perform cesarean sections on hypothetical patients described in the questionnaire. These differences appeared to be due to the high users' higher estimate of danger to the fetus. We also found that most physicians were generally more likely to perform a cesarean section on a high-risk mother than a low-risk mother with the same tracing. The majority of high and low users and nearly all of the experts, however, felt that antepartum risk factors are not of value in deciding what to do about an abnormal tracing. We conclude that there is wide variation in the way in which obstetricians use, interpret, and act on electronic fetal monitoring tracings. Some of these differences may be due to differing attitudes toward electronic fetal monitoring, differences in interpretation of electronic fetal monitoring tracings, and differences in the way obstetricians incorporate maternal risk factors into their decision-making.