Effect of Different Labour Analgesics on Maternal and Fetal Blood Flow Observed by Doppler Ultrasonography
Condition: Labor Pain; Analgesia; Fetus Disorder
MeSH terms: Labor Pain
Study type: Observational

Summary: 
      Background: The purpose of this study was to see how intrathecal injections of sufentanil,
      ropivacaine, and sufentanil added to ropivacaine affected blood flow in the uterine artery,
      umbilical artery, and middle cerebral artery for combined spinal and epidural labor analgesia
      using color doppler ultrasound (CDUs).

      Methods: A total of 90 singleton full-term parturients who were evaluated by obstetricians
      for feasible vaginal delivery were collected prospectively and divided into three groups
      based on the randomization and double-blind principle: sufentanil (S), ropivacaine (R) group,
      each with 30 cases. Main indicators include color doppler blood flow resistance indices (S/D)
      of the uterine artery (UtA), umbilical artery (UA), and middle cerebral artery (MCA) before
      (T0) and 30 minutes (T1), 60 minutes (T2), 90minutes (T3) after analgesia. Fetal heart rate
      (FHR), maternal mean arterial pressure (MAP) at T0, T1, T2 and T3。
    

Detailed description: 
      1. Randomization and blinding Parturients in the study were randomly assigned to Sufentanil
           group (S) and Ropivacaine group (R) by non-blind personnel according to the computer
           random number table, and the allocation was hidden. The solution was prepared by an
           unblinded anesthesiologist and packaged in a blind way and administered by another
           anesthesiologist. The patients, anesthesia providers, data recorders, ultrasound
           examiners, obstetrical staff, and nursing staff remained blinded to group assignment
           throughout the study.

        2. Study intervention At the time of request for labor analgesia, patients were randomized
           to receive either sufentanil 5 μg (Group S) and ropivacaine 3mg (Group R) into the
           subarachnoid space. All groups received the standard epidural solution that contained
           0.1% ropivacaine with 0.25 μg/ml sufentanil. Routine obstetric and anaesthetic
           monitoring was given after maternal entered the delivery room. An experienced the
           anesthesiologist select L3-4 lumbar vertebra clearance to puncture with standard sterile
           technique using loss of resistance when the puerpera palace has expanded to about 3 cm.
           After the puncture reached the epidural space, a 25-gauge lumbar anesthesia needle was
           used to puncture into the subarachnoid space. 2 mL of anesthetic drug as determined by
           her group randomization were administered into the cavity through the lumbar anesthesia
           needle after cerebrospinal fluid flow out. A 19-gauge spring-wound catheter was threaded
           4-6 cm into the epidural space. All patients received a test dose of 3 ml of 1.5%
           lidocaine followed by an initial loading dose of 5 ml of the standard epidural solution.
           Epidural catheters into vessels or subarachnoid space were excluded. An analgesic pump
           (PCEA pump, 100ml) containing standard epidural solution was then connected to the
           epidural catheter at a background continuous infusion rate of 5 mL/h. The visual
           analogue score for pain (VAS) was performed 15 minutes after the injection dose, and if
           the VAS score fell below 3, the case was included in the study.

           An anesthesia provider assessed the adequacy of analgesia for the patients throughout
           the duration of labor. Any breakthrough pain was managed with a physician-administered
           epidural bolus. All obstetric analgesia procedures were performed by the same
           anesthesiologist to reduce errors due to technical reasons.

        3. Ultrasonic examination method The patients were placed in a supine position with calm
           breathing to perform doppler ultrasonography during the interval of contractions.
           Ultrasound probe was placed on fetal head area. Middle cerebral arteries (MCA) run
           anteriorly on both sides of the ring of cerebral arteries at the position of the double
           head diameter (see Figure 1A). We can get waveforms of MCA examined by pulsed wave
           doppler (see Figure 1B). The probe was placed at the placenta area, and we can see the
           fetal umbilical cord connecting to the center of the placenta. Umbilical artery (UA)
           could be identified by color flow, and its waveforms were examined by pulsed wave
           doppler (see Figure 1C and 1D). The probe was placed at the midpoint of the groin. The
           right and left uterine arteries (UtA) could be identified by color flow at the apparent
           crossover with the external iliac arteries, and pulsed wave doppler was used to obtain
           waveforms (see Figure 1E and 1F). 3 to 10 arterial spectrograms with clear edges and no
           background noise at baseline were selected. The above arterial blood flow indexes were
           measured three times and the average value was taken. The S/Dvalue of MCA、UA、UtA can be
           measured automatically by ultrasound instrument. All doppler examinations were performed
           by the same sonographer.
    

Intervention name(s): sufentanil, ropivacaine
Intervention type(s): Drug
Intervention description(s): The study used conventional anesthetic drugs to compare the effects of the two drugs on maternal and infant blood flow
Other intervention name(s): Color Doppler ultrasound
Intervention MeSH terms: Sufentanil; Ropivacaine
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        ASA grade I to II, aged 20 to 35 years, weighing 50 to 100 kg, 150-175 cm in height, and 37
        to 41 weeks of gestation
      
Keywords: Sufentanil; Ropivacaine; Labor analgesia; Color Doppler ultrasound; Middle cerebral artery; Uterine artery; Umbilical artery