The Ovine Fetal and Placental Inflammatory Response to Umbilical Cord Occlusions With Worsening Acidosis

How does fetal inflammatory response syndrome change fetal response to hypoxia? An experimental study in a fetal sheep model

INTRODUCTION

Fetal inflammatory response syndrome associated with acidosis during labor is a high-risk situation for the fetus. This study evaluated hemodynamic, gasometric, and heart rate variability changes during acute fetal inflammatory response syndrome associated with hypoxia, compared with isolated hypoxia.

MATERIAL AND METHODS

Acute fetal inflammatory response syndrome was obtained via an intravenously injection of lipopolysaccharide derived from Escherichia coli. Hypoxia was induced by repeated umbilical cord occlusions during three phases: mild, moderate, and severe umbilical cord occlusions. Two groups were created with chronically instrumented near-term fetal sheep: one group with isolated hypoxia, the other with hypoxia and fetal inflammatory response syndrome. Hemodynamic, gas parameters, and fetal heart rate variability were compared between the groups.

RESULTS

The hypoxia and fetal inflammatory response syndrome group had a higher mortality rate (n = 4/9) compared with the hypoxia group (n = 0/9). Gasometric state was altered earlier in case of lipopolysaccharide injection (pH = 7.22 (7.12-7.24) vs 7.28 (7.23-7.34) p = 0.01; lactate = 10.3 mmol/L (9.4-11.0) vs 6.0 mmol/L (4.1-8.2) p < 0.001 after mild occlusions). After mild occlusions, the hypoxia and fetal inflammatory response syndrome group had higher values on seven heart rate variability parameters compared with the hypoxia group. After moderate occlusions, two parameters remained significantly higher.

CONCLUSIONS

During fetal inflammatory response syndrome, fetal adaptation to hypoxia is impaired. In case of fetal infection, acidosis during labor is likely to become severe more rapidly, requiring closer fetal monitoring during labor.

Different Doses of Ropivacaine either with Sufentanil or with Dexmedetomidine for Labor Epidural Anesthesia regarding Painless Childbirth: A Retrospective, Multicenter Study

INTRODUCTION

Sufentanil is used with ropivacaine in labor pain management but it can have respiratory depression. Dexmedetomidine is effective to maintain hemodynamic stability in parturient women and allow awake intubation. However, dexmedetomidine is suggested only in patients with major cardiovascular disease that mandates stable hemodynamics (Reference ID: 3987541-USFDA). The objective of the study was to compare different doses of ropivacaine either with sufentanil or with dexmedetomidine for epidural anesthesia regarding labor pain management.

METHODS

Parturient women have received 0.125% ropivacaine with 0.5-μg/mL sufentanil (SR1 cohort, n = 115), or 0.08% ropivacaine with 0.5-μg/mL sufentanil (SR2 cohort, n = 109), or 0.125% ropivacaine with 0.5-μg/mL dexmedetomidine (DR1 cohort, n = 124), or 0.08% ropivacaine with 0.5-μg/mL dexmedetomidine (DR2 cohort, n = 135) for epidural anesthesia during vaginal delivery or cesarean section.

RESULTS

At 2-h postpartum, the visual analog scale score of parturient women of the DR2 cohort was fewer than that of parturient women of the SR1 (p < 0.0001, q = 4.162) and the SR2 (p < 0.0001, q = 7.568) cohorts and statistically the same as that of parturient women of the DR1 cohort (p < 0.0001, q = 3.087). Bradycardia and itching were reported in parturient women of the DR2 and the DR1 cohorts while nausea, vomiting, and urinary retention at 6 h were reported in parturient women of the SR1 and the SR2 cohorts. In the DR2 cohort, there were fewer numbers of parturient women with bradycardia (4 vs. 19, p < 0.0001, q = 6.613) and hypotension (2% vs. 1%) than those in the DR1 cohort. The child born by women of the DR2 cohort had high partial arterial pressure of oxygen than those born by women of the DR1 (p < 0.0001, q = 18.663), the SR1 (p < 0.0001, q = 29.366), and the SR2 (p < 0.0001, q = 24.039) cohorts.

DISCUSSION/CONCLUSION

Epidural 0.08% ropivacaine with 0.5-μg/mL dexmedetomidine is an effective and safe anesthetic regimen for hypertensive parturient women and their newborns.

LEVEL OF EVIDENCE

III. Technical Efficacy Stage: 4.

Opioid-Free Labor Analgesia: Dexmedetomidine as an Adjuvant Combined with Ropivacaine

Background

Side effects of the use of opioid analgesics during painless delivery are the main factors that affect rapid postpartum recovery. Opioid use can result in dangerous respiratory depression in the patient. Opioids can also disrupt the baby's breathing and heart rate. The nonopioid analgesic dexmedetomidine, a new a2-adrenergic agonist, possesses higher selectivity, greater analgesic effects, and fewer side effects. Moreover, epidural administration of dexmedetomidine also reduces local anesthetic consumption.

Objective

Our study aims to compare the analgesic effects as well as the side effects of ropivacaine with dexmedetomidine against sufentanyl as an epidural labor analgesia.

Methods

This study is a randomized, double-blinded, controlled trial (registration no. ChiCTR2200055360) involving 120 primiparous (a woman who has given birth once), singleton pregnancy women who are greater than 38 weeks into gestation and have requested epidural labor analgesia. The participants were randomized to receive 0.1% ropivacaine with sufentanyl (0.4 μg/ml) or dexmedetomidine (0.4 μg/ml). The primary outcomes included Visual Analogue Score (VAS), duration of first epidural infusions, the requirement of additional PCEA bolus, and adverse reactions during labor analgesia.

Results

Of the 120 subjects who consented, 91 parturient women (women in the condition of labor) had complete data for analysis. Demographics and VAS, as well as maternal and fetal outcomes, were similar between the groups. The duration of first epidural infusions in dexmedetomidine was significantly longer than sufentanyl (median value: 115 vs 68 min, P < 0.01); the parturient women who received dexmedetomidine and who required additional PCEA bolus were fewer in comparison to those who received sufentanyl (27.5% vs 49.0%, P < 0.05). Furthermore, the incidence of pruritus in the dexmedetomidine group was lower in comparison to the sufentanyl group (0% vs 11.8%, P < 0.05).

Conclusions

Dexmedetomidine, a nonopioid, is superior to the opioid analgesic sufentanyl in providing a prolonged analgesic effect as an epidural during labor. It also reduces local anesthetic consumption and has fewer side effects. The trial is registered with ChiCTR2200055360.

Distance to Healthy Metabolic and Cardiovascular Dynamics From Fetal Heart Rate Scale-Dependent Features in Pregnant Sheep Model of Human Labor Predicts the Evolution of Acidemia and Cardiovascular Decompensation

The overarching goal of the present work is to contribute to the understanding of the relations between fetal heart rate (FHR) temporal dynamics and the well-being of the fetus, notably in terms of predicting the evolution of lactate, pH and cardiovascular decompensation (CVD). It makes uses of an established animal model of human labor, where 14 near-term ovine fetuses subjected to umbilical cord occlusions (UCO) were instrumented to permit regular intermittent measurements of metabolites lactate and base excess, pH, and continuous recording of electrocardiogram (ECG) and systemic arterial blood pressure (to identify CVD) during UCO. ECG-derived FHR was digitized at the sampling rate of 1,000 Hz and resampled to 4 Hz, as used in clinical routine. We focused on four FHR variability features which are tunable to temporal scales of FHR dynamics, robustly computable from FHR sampled at 4 Hz and within short-time sliding windows, hence permitting a time-dependent, or local, analysis of FHR which helps dealing with signal noise. Results show the sensitivity of the proposed features for early detection of CVD, correlation to metabolites and pH, useful for early acidosis detection and the importance of coarse time scales (2.5-8 s) which are not disturbed by the low FHR sampling rate. Further, we introduce the performance of an individualized self-referencing metric of the distance to healthy state, based on a combination of the four features. We demonstrate that this novel metric, applied to clinically available FHR temporal dynamics alone, accurately predicts the time occurrence of CVD which heralds a clinically significant degradation of the fetal health reserve to tolerate the trial of labor.

Dexmedetomidine versus sufentanil with high- or low-concentration ropivacaine for labor epidural analgesia: A randomized trial

AIM

To study analgesic effects of dexmedetomidine or sufentanil, both combined with ropivacaine, in epidural analgesia during labor.

METHODS

We recruited 160 primigravidae with full-term pregnancy who received epidural anesthesia during labor and randomized them into four groups to receive epidural administration of ropivacaine combined with sufentanil (RS₁ and RS₂ groups) or with dexmedetomidine (RD₁ and RD₂ groups). Systolic blood pressure, diastolic blood pressure and heart rate before anesthesia (T₁ ), 15 min after anesthesia induction (T₂ ), on delivery (T₃ ) and 2 h postpartum (T₄ ), together with visual analogue scale scores, Bromage scores, Ramsay scores, adverse reactions during analgesia and urinary retention at 6 and 24 h postpartum were recorded; the pH, PCO₂ and PO₂ of umbilical cord arterial blood and Apgar scores at 1, 5 and 10 min after childbirth were assessed.

RESULTS

RS₁ group had significantly lower systolic blood pressure, diastolic blood pressure and heart rate than RD₁ group at T₂ and T₃ (all P < 0.05), but not at T1. At T₂ and T₃ , the other three groups were lower than RS₂ group in visual analogue scale and Ramsay scores (all P < 0.05). After childbirth, RD₂ group had significantly higher PO₂ result than other three groups (P < 0.05). At 6 h postpartum, RD₂ group had significantly fewer cases of urinary retention than RD₁ and RS₁ groups (both P < 0.05).

CONCLUSION

A relatively low concentration of ropivacaine, combined with dexmedetomidine, is better in analgesia during labor.

Instrumentation of Near-term Fetal Sheep for Multivariate Chronic Non-anesthetized Recordings

The chronically instrumented pregnant sheep has been used as a model of human fetal development and responses to pathophysiologic stimuli such as endotoxins, bacteria, umbilical cord occlusions, hypoxia and various pharmacological treatments. The life-saving clinical practices of glucocorticoid treatment in fetuses at risk of premature birth and the therapeutic hypothermia have been developed in this model. This is due to the unique amenability of the non-anesthetized fetal sheep to the surgical placement and maintenance of catheters and electrodes, allowing repetitive blood sampling, substance injection, recording of bioelectrical activity, application of electric stimulation and in vivo organ imaging. Here we describe the surgical instrumentation procedure required to achieve a stable chronically instrumented non-anesthetized fetal sheep model including characterization of the post-operative recovery from blood gas, metabolic and inflammation standpoints.

Adaptive shut-down of EEG activity predicts critical acidemia in the near-term ovine fetus

In fetal sheep, the electrocorticogram (ECOG) recorded directly from the cortex during repetitive heart rate (FHR) decelerations induced by umbilical cord occlusions (UCO) predictably correlates with worsening hypoxic-acidemia. In human fetal monitoring during labor, the equivalent electroencephalogram (EEG) can be recorded noninvasively from the scalp. We tested the hypothesis that combined fetal EEG – FHR monitoring allows for early detection of worsening hypoxic-acidemia similar to that shown for ECOG-FHR monitoring. Near-term fetal sheep (n = 9) were chronically instrumented with arterial and venous catheters, ECG, ECOG, and EEG electrodes and umbilical cord occluder, followed by 4 days of recovery. Repetitive UCOs of 1 min duration and increasing strength (with regard to the degree of reduction in umbilical blood flow) were induced each 2.5 min until pH dropped to <7.00. Repetitive UCOs led to marked acidosis (arterial pH 7.35 ± 0.01 to 7.00 ± 0.03). At pH of 7.22 ± 0.03 (range 7.32–7.07), and 45 ± 9 min (range 1 h 33 min–20 min) prior to attaining pH < 7.00, both ECOG and EEG amplitudes began to decrease ∼fourfold during each FHR deceleration in a synchronized manner. Confirming our hypothesis, these findings support fetal EEG as a useful adjunct to FHR monitoring during human labor for early detection of incipient fetal acidemia.