Sinusoidal fetal heart rate pattern after administration of nalbuphine hydrochloride: a case report

Retrospective study of the effect of remifentanil use during labor on fetal heart rate patterns

OBJECTIVE

To investigate possible associations between remifentanil and the appearance of sinusoidal heart rate patterns in fetuses, and neonatal outcomes.

METHODS

The present retrospective cohort study included data from patients at over 37 weeks of singleton or multiple pregnancies attending Zuyderland Medical Center, Sittard, the Netherlands, in labor between June 1, and August 31, 2015. Patient data were stratified by whether remifentanil was administered during delivery (remifentanil group) or not (control group), and fetal heart rate tracings were reviewed to identify sinusoidal heart rate patterns. The neonatal outcomes compared were 5-minute Apgar scores and umbilical artery pH.

RESULTS

There were 119 patients included in the study; 60 in the remifentanil group and 59 in the control group. Tracings from 20 (33%) patients in the remifentanil group exhibited a sinusoidal heart rate pattern after remifentanil administration, compared with 5 (8%) patients in the control group (P=0.001). The median time before the onset of sinusoidal patterns after remifentanil administration was 12 minutes. No adverse neonatal outcomes were recorded in either group.

CONCLUSION

Remifentanil use during labor was associated with the occurrence of sinusoidal heart rate patterns in the fetus; this was not associated with adverse neonatal outcomes.

When one drug affects 2 patients: a review of medication for the management of nonlabor-related pain, sedation, infection, and hypertension in the hospitalized pregnant patient

One of the most difficult challenges health care providers encounter is drug selection for pregnant patients. Drug selection can be complex as efficacy and maternal side effects must be weighed against potential risk to the embryo or fetus. Verification of an individual drug's fetal safety is limited as most evidence is deduced from epidemiologic, prospective cohort, or case-control studies. Medication selection for the pregnant inpatient is a particularly complex task as the illnesses and conditions that require hospitalization mandate different medications, and the risk versus benefit ratio can vary significantly compared to the outpatient setting. Some degree of acute pain is not uncommon among inpatients. Acetaminophen is generally considered the drug of choice in pregnancy for mild to moderate acute pain, while most opioids are thought to be safe for short-term use to manage moderate to severe pain. Providing sedation is particularly challenging as the few options available for the general population are further limited by either known increased risk of congenital malformations or very limited human pregnancy data. Propofol is the only agent recommended for continuous sedation, which has a Food and Drug Administration classification as a pregnancy category B medication. Treatment of infections in hospitalized patients requires balancing the microbiology profile against the fetal risk. Older antimicrobials proven generally safe include beta-lactams, and those with proven fetal risks include tetracyclines. However, little to no information regarding gestational use is available on the newer antimicrobials that are frequently employed to treat resistant infections more commonly found in the inpatient setting. Management of maternal blood pressure is based on the severity of blood pressure elevations and not the hypertensive classification. Agents generally considered safe to use in hypertensive pregnant patients include methyldopa, labetolol, and hydralazine, while angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, hydrochlorothiazide, and atenolol should be avoided.

Douleur du nouveau-né : traitement pharmacologique

Pain causes numerous physiological changes in neonates. All invasive procedures induce undesirable stress responses; theses responses can, however, be eliminated or reduced by a judicious use of analgesia. Even though a large number of analgesics and sedatives are currently available, most of them have not been studied in the neonate. At present, a precise understanding of the pharmacological mechanisms of analgesics is difficult because many interactions still remain unknown in the term and premature neonate. This article describes the main analgesics and sedative agents used in the neonate: morphine, fentanyl, sufentanil, alfentanil, nalbuphine, ketamine, midazolam, propofol, acetaminophen, and Emla cream. After a review of the literature regarding these drugs, some practical advices and suggestions for the treatment of procedure-induced pain, and background sedation/analgesia for ventilated neonates are given. It is also stated in this article that the best way to soothe pain in neonates is to combine non pharmacological and pharmacological strategies. At the national level, written guidelines should be prepared in order to improve pain management in the neonate.

Automatic Computerized Diagnosis of Fetal Sinusoidal Heart Rate

OBJECTIVES

Computerized automatic detection of pathologic fetal sinusoidal heart rate (FSHR) and its differentiation from physiologic FSHR is the purpose of this study. The results will be applied in the objective evaluation of fetal heart rate (FHR) with artificial neural network computer.

METHODS

FHR tracings of pathologic FSHR of 9 cases of fetal-neonatal anemia, death, or severe asphyxia, those of 7 physiologic FSHR followed by normal outcome, and those of 5 normal FHR are processed with fast Fourier transform (FFT) analysis after digitization, and their power spectrums are obtained. The peak power spectrum frequency (PPSF), peak power spectrum density (PPSD), the area under the power spectrum of 0.03125-0.1 Hz (La), the area under the whole power spectrum (Ta), and the ratio of La/Ta (%) of pathologic FSHR are compared to those of physiologic FSHR and normal FHR.

RESULTS

The La/Ta ratio and PPSD are significantly larger in the pathologic FSHR than those of physiologic FSHR and normal FHR. The true positive rate is 100%, false negative and false positive rates are 0%, respectively, when the pathologic FSHR is diagnosed by such combined criteria as 39% or more of La/Ta ratio and 300 or more of PPSD.

CONCLUSION

Pathologic FSHR is clearly separated from physiologic FSHR and normal FHR by the La/Ta ratio and PPSD obtained by FFT frequency analysis of FHR. Consequently, it is capable to automatically diagnose pathologic FSHR, and to apply it to neural network computer evaluation of FHR.

Sinusoidal heart rate pattern: Reappraisal of its definition and clinical significance

OBJECTIVES

To address the clinical significance of sinusoidal heart rate (SHR) pattern and review its occurrence, define its characteristics, and explain its physiopathology.

BACKGROUND

In 1972, Manseau et al. and Kubli et al. described an undulating wave form alternating with a flat or smooth baseline fetal heart rate (FHR) in severely affected, Rh-sensitized and dying fetuses. This FHR pattern was called 'sinusoidal' because of its sine waveform. Subsequently, Modanlou et al. described SHR pattern associated with fetal to maternal hemorrhage causing severe fetal anemia and hydrops fetalis. Both Manseau et al. and Kubli et al. stated that this particular FHR pattern, whatever its pathogenesis, was an extremely significant finding that implied severe fetal jeopardy and impending fetal death. UNDULATING FHR PATTERN: Undulating FHR pattern may be due to the following: (1) true SHR pattern; (2) drugs; (3) pre-mortem FHR pattern; (4) pseudo-SHR pattern; and (5) equivocal FHR patterns. FETAL CONDITIONS ASSOCIATED WITH SHR PATTERN: SHR pattern has been reported with the following fetal conditions: (1) severe fetal anemia of several etiologies; (2) effects of drugs, particularly narcotics; (3) fetal asphyxia/hypoxia; (4) fetal infection; (5) fetal cardiac anomalies; (6) fetal sleep cycles; and (7) sucking and rhythmic movements of fetal mouth. DEFINITION OF TRUE SHR PATTERN: Modanlou and Freeman proposed the following definition for the interpretation of true SHR pattern: (a) stable baseline FHR of 120-160 bpm; (b) amplitude of 5-15 bpm, rarely greater; (c) frequency of 2-5 cycles per minute; (d) fixed or flat short-term variability; (e) oscillation of the sinusoidal wave from above and below a baseline; and (f) no areas of normal FHR variability or reactivity.

PHYSIOPATHOLOGY

Since its early recognition, the physiopathology of SHR became a matter of debate. Murata et al. noted a rise of arginine vasopressin levels in the blood of posthemorrhagic/anemic fetal lamb. Further works by the same authors revealed that with chemical or surgical vagotomy, arginine vasopressin infusion produced SHR pattern, thus providing the role of autonomic nervous system dysfunction combined with the increase in arginine vasopressin as the etiology.

CONCLUSION

SHR is a rare occurrence. A true SHR is an ominous sign of fetal jeopardy needing immediate intervention. The correct diagnosis of true SHR pattern should also include fetal biophysical profile and the absence of drugs such as narcotics.

Drugs that affect the fetus and newborn infant via the placenta or breast milk

In general, drugs that are taken by a mother during pregnancy or after birth may be transferred to the fetus or the infant (through breast milk). Many factors are involved that determine the amount of drugs that are transferred and their potential effects on the fetus or infant. A careful assessment of the risk versus benefit is necessary and should be individualized. In the breastfed infant, many measures can be undertaken further so that the amount of drug transferred to the infant is minimized.

Rapid and sensitive high-performance liquid chromatographic assay for nalbuphine in plasma

A simple and reliable reversed-phase high-performance liquid chromatographic method with adequate internal analog standardization and coulometric detection is described for the quantification of nalbuphine in plasma samples. The lower limit of detection was estimated to be 0.1 ng/ml. For routine analysis, the limit of quantification was set at 0.5 ng/ml and only a small plasma volume (500 microliters) was required. The nalbuphine calibration curve was linear over the concentration range 0-100 ng/ml. The recoveries of nalbuphine and 6-monoacetylmorphine, used as internal standard, were close to 85%. Due to the small sample volume of blood required, this highly sensitive, accurate and specific method is suitable for pharmacokinetic studies of nalbuphine, and particularly for drug monitoring in neonates born from mothers treated with nalbuphine.

Maternal and fetal effects of intravenous patient-controlled fentanyl analgesia during labour in a thrombocytopenic parturient

The use of intravenous (i.v.) patient-controlled fentanyl analgesia during labour in a parturient with unexplained thrombocytopenia (70 x 10(3).ml-1) is described. The patient self-administered boluses of 25 micrograms of fentanyl with a lock-out interval of ten min. In addition, a concurrent fentanyl infusion of 25 micrograms.hr-1 was given. Effective analgesia was achieved during labour and a total of 1025 micrograms of fentanyl was infused over 11 hr 55 min until delivery of a vigorous infant with Apgar scores of 9 after one and five min. Respiratory depression or undue sedation were not observed in the mother either during labour or in the post-partum period. At birth, maternal total plasma fentanyl concentration was 1.11 ng.ml-1, whereas neonatal umbilical total plasma fentanyl concentration was 0.43 ng.ml-1. Newborn plasma protein binding of fentanyl was lower compared to the mother (63% vs 89%). Thus, free fentanyl concentrations (0.16 ng.ml-1) were identical in the mother and newborn at delivery.

The aetiology and clinical significance of the sinusoidal fetal heart-rate pattern; two case reports

Two cases are presented in which sinusoidal heart-rate (SHR) patterns were recorded antenatally. In the first case the pattern was associated with severe maternal exertion and prolonged exposure to freezing temperatures. The pattern returned to normal within an hour of maternal recovery. The second case was associated with fetal death due to high-output cardiac failure associated with a large liver haemangioma. A hypothesis is proposed to link the aetiology for this heart-rate pattern which would explain these, and previously reported cases.

An approach to interpretation and classification of sinusoidal fetal heart rate patterns

Sinusoidal fetal heart rate (SHR) records were obtained in 8 cases, either antepartum (3 cases of fetal Rh disease) or intrapartum (one case with an acute episode of fetomaternal transfusion as possible cause, 2 after meperidine administration to the mother and 2 others without attributable causes). Characteristics of both SHR patterns and related clinical pictures are described and compared to similar cases published elsewhere. The possible underlying mechanisms of SHR are discussed. Two different profiles of SHR patterns (smooth and jagged waveforms) are characterized and correlated with their most usual clinical backgrounds and prognostic significance. A classification of SHR into 2 main types is proposed, with clinical use in mind.

Intrapartum fetal monitoring

From the fetal viewpoint, labour is a prolonged contraction stress test which most pass without incident. Labour also represents the obstetrician's last opportunity to influence perinatal outcome and ensure that those fetuses who have suffered chronic hypoxia antenatally are recognized promptly, so that labour is supervised in a way that does not place them at increased risk of either death or birth asphyxia. In the case of the fetus who enters labour healthy, with normal reserves, labour is managed with the same aim in mind, but with the foreknowledge that visualization of a normal volume of clear amniotic fluid and reasonable duration of labour makes the development of hypoxia and asphyxia unlikely. Those at increased risk of hypoxia should be monitored electronically, but, for the remainder, intermittent auscultation is satisfactory until labour lasts in excess of 5 hours, or if the patient requires oxytocin, or if an epidural is placed. If EFM is used, then it is important to provide adequate education in trace interpretation, with particular emphasis on the importance of short-term variability. Widespread use of EFM has provided us with an immense amount of knowledge about fetal physiology, but it is critically important for the practising obstetrician to understand that, in the low-risk patient, EFM is not more effective than IA in preventing death from asphyxia, that EFM does protect against asphyxial seizures, but that widespread use of the technique has not been associated with a significant reduction in the population of permanently handicapped infants. This information is particularly relevant in developing nations where money spent on sophisticated monitoring equipment might be better spent in other areas. From the maternal point of view, intensive fetal monitoring has profound implications by virtue of its usual effect on incidence of Caesarean birth, although the Dublin trial results, with regard to incidence of Caesarean section, emphasize the importance of considering intrapartum fetal monitoring as just one part of the overall supervision of labour. Finally, it must be emphasized that the method of fetal monitoring chosen may be strongly influenced by factors other than scientific evidence, as in the United States where the medicolegal climate is such that failure to rigorously document absence of fetal distress/true birth asphyxia may result in a harrowing lawsuit. It is a position this author has developed considerable sympathy with in recent years.