The effect of propofol on isolated human pregnant uterine muscle

Exploring the Utility of remimazolam in cesarean sections under general anesthesia: A preliminary retrospective analysis and Implications for future study

Background

Remimazolam has recently been introduced as a maintenance agent for general anesthesia. However, the effect of remimazolam on peripartum prognosis has not been reported. Therefore, this study aimed to compare the effects of remimazolam and propofol for uterotonic drugs following cesarean section.

Methods

The electronic medical records of 51 adult women who underwent elective cesarean sections by single obstetrician under general anesthesia were collected. Participants were categorized into two groups: the propofol group and the remimazolam group. General anesthesia was maintained by continuous infusion of propofol or remimazolam after delivery. The number of uterotonic drugs administered during the cesarean section, the estimated blood loss (EBL), and length of hospital stay (LOS) after delivery were assessed.

Results

Of the 51 patients included in the study, 35 were in the propofol group and 16 in the remimazolam group. In the remimazolam group, five patients (31.3%, 5/16) received more uterotonics than the standard regimen. Conversely, in the propofol group, 19 patients (54.3%, 19/35) were injected with more uterotonics than the standard regimen. Logistic regression analysis showed that abnormal positioning of the placenta (P = 0.079) and not using remimazolam (P = 0.100) were the most relevant factors associated with the increased use of uterotonics. There was no significant difference in EBL between the two groups. The use of remimazolam was clinically relevant with a shorter LOS (P = 0.059).

Conclusions

The use of remimazolam as a maintenance agent did not result in significantly higher use of intrapartum uterotonics compared to the use of propofol. These results cannot exclude all adverse effects of remimazolam during cesarean delivery. Further randomized controlled trials must be conducted to obtain high-quality evidence.

In vitro contractile studies within isolated tissue baths: Translational research from Visible Heart® Laboratories

The isolated tissue bath research methodology was first developed in 1904. Since then, it has been recognized as an important tool in pharmacology and physiology research, including investigations into neuromuscular disorders. The tissue bath is still used routinely as the instrument for performing the "gold standard" test for clinical diagnosis of malignant hyperthermia susceptibility - the caffeine-halothane contracture test. Our research group has utilized this tool for several decades for a range of research studies, and we are currently one of four North American diagnostic centers for determining susceptibility for malignant hyperthermia. This review provides a brief summary of some of the historical uses of the tissue bath. Important experimental considerations for the operation of the tissue bath are further described. Finally, we discuss the different studies our group has performed using isolated tissue baths to highlight the broad potential applications.

Liver and Biliary Disease of Pregnancy and Anesthetic Implications: A Review

Liver and biliary disease complicates pregnancy in varying degrees of severity to the mother and fetus, and anesthesiologists may be asked to assist in caring for these patients before, during, and after birth of the fetus. Therefore, it is important to be familiar with how different liver diseases impact the pregnancy state. In addition, knowing symptoms, signs, and laboratory markers in the context of a pregnant patient will lead to faster diagnosis and treatment of such patients. This review article discusses changes in physiology of parturients, patients with liver disease, and parturients with liver disease. Next, general treatment of parturients with acute and chronic liver dysfunction is presented. The article progresses to specific liver diseases with treatments as they relate to pregnancy. And finally, important aspects to consider when anesthetizing parturients with liver disease are discussed.

Effect of continuous infusion of a subhypnotic dose of propofol on nausea and vomiting after carboprost administration at cesarean delivery: A randomized, double-blind, placebo-controlled trial

OBJECTIVE

To investigate whether continuous infusion of propofol at a subhypnotic dose prevents nausea and vomiting following carboprost administration at cesarean delivery.

METHODS

A prospective, randomized, double-blind, placebo-controlled trial conducted at West China Second University Hospital, from June 28, 2017 to January 30, 2018. Pregnant women were randomly allocated to propofol or saline infusion immediately before receiving carboprost at cesarean delivery under combined spinal-epidural (CSE) anesthesia. Propofol was given at an infusion rate of 1.0 mg/kg/h following a loading dose of 0.3 mg/kg. Primary outcome was incidence of intraoperative nausea and vomiting (IONV). Potential sedative effect of propofol infusion was assessed using Modified Observer's Assessment of Alertness and Sedation (MOAA/S) scoring and continuous Bispectral Index (BIS) monitoring.

RESULTS

The incidence of IONV was lower in patients who received propofol compared with saline (46.7% vs 76.7%, OR 0.27; 95% CI, 0.092-0.78, P = 0.016 for nausea; 26.7% vs 53.3%, OR 0.50; 95% CI, 0.25-0.95, P = 0.032 for retching; 10.0% vs 50.0%, OR 0.11; 95% CI, 0.03-0.44, P < 0.001 for vomiting). There were no differences in MOAA/S scoring or BIS between the two groups.

CONCLUSION

A subhypnotic dose of propofol reduces the incidence of nausea and vomiting following carboprost administration at cesarean delivery under CSE anesthesia, without measurable effect on patients' consciousness or alertness. ClincalTrials.gov: NCT03185156.

Effects of anesthetic agents on contractions of the pregnant rat myometrium in vivo and in vitro

BACKGROUND

Several anesthetic agents are used in cesarean sections for both regional and general anesthesia purposes. However, there are no data comparing the in vivo effects of propofol, sevoflurane, and dexmedetomidine on the contraction of the myometrium in pregnant rats. The aim of this study was to investigate the effect of these anesthetic agents on myometrial contraction and elucidate the underlying mechanisms.

METHODS

Contraction force and frequency changes in response to propofol, dexmedetomidine, or sevoflurane were evaluated in vivo and in vitro. To test the effect of arachidonic acid on myometrial contraction enhanced by dexmedetomidine, changes in myometrial contraction with dexmedetomidine after administration of indomethacin were evaluated. The amount of phosphorylated myosin phosphatase target subunit 1 (MYPT1) in the membrane fraction was expressed as a percentage of the total fraction by Western blot analysis.

RESULTS

This study demonstrated that dexmedetomidine enhances oxytocin-induced contraction in the myometrium of pregnant rats, whereas propofol and sevoflurane attenuate these contractions. The dexmedetomidine-induced enhancement of myometrial contraction force was abolished by the administration of indomethacin. Propofol did not affect oxytocin-induced MYPT1 phosphorylation, whereas sevoflurane attenuated oxytocin-induced MYPT1 phosphorylation.

CONCLUSIONS

Inhibition of myofilament calcium sensitivity may underlie the inhibition of myometrial contraction induced by sevoflurane. Arachidonic acid may play an important role in the enhancement of myometrial contraction induced by dexmedetomidine by increasing myofilament calcium sensitivity. Dexmedetomidine may be used as a sedative agent to promote uterine muscle contraction and suppress bleeding after fetal delivery.

Use of Remifentanil for Open in utero Fetal Myelomeningocele Repair Maintains Uterine Relaxation with Reduced Volatile Anesthetic Concentration

INTRODUCTION

Open fetal repair of myelomeningocele (MMC) is an option for prenatally diagnosed spina bifida. Historically, high-dose volatile anesthetic was used for uterine relaxation but is associated with fetal cardiovascular depression. We examined the impact of administering a supplemental remifentanil infusion on the concentration of inhaled anesthetic required for intraoperative uterine relaxation.

METHODS

We retrospectively analyzed 22 consecutive patients who underwent open fetal MMC repair with desflurane anesthesia from 2014 to 2018. The anesthetic protocol was modified to include high-dose opioid with remifentanil in 2016. We examined intraoperative end-tidal desflurane concentrations, vasopressor use, incidence of umbilical artery Doppler abnormalities, and incidence of preterm labor and delivery.

RESULTS

Patients (n = 11) who received desflurane and remifentanil (Des/Remi) were compared to patients (n = 11) who received desflurane (Des) alone. Intraoperatively, the maximum end-tidal desflurane required to maintain uterine relaxation was lower in the Des/Remi group (7.9 ± 2.2% vs. 13.1 ± 1.2%, p < 0.001). The mean phenylephrine infusion rate was also lower in the Des/Remi group (36 ± 14 vs. 53 ± 10 mcg/min, p = 0.004).

DISCUSSION

Use of opioid with supplemental remifentanil was associated with lower volatile anesthetic dosing and decreased vasopressor use; fetal outcomes were not different. Remifentanil may allow for less volatile anesthetic use while maintaining adequate uterine relaxation.

Effects of remifentanil preconditioning on factors related to uterine contraction in WISH cells

Background

Preterm labor and miscarriage may occur in stressful situations, such as a surgical operation or infection during pregnancy. Pharyngeal and buccal abscess and facial bone fractures are inevitable dental surgeries in pregnant patients. Remifentanil is an opioid analgesic that is commonly used for general anesthesia and sedation. Nonetheless, no study has investigated the effects of remifentanil on amniotic epithelial cells. This study evaluated the effects of remifentanil on the factors related to uterine contraction and its mechanism of action on amniotic epithelial cells.

Methods

Amniotic epithelial cells were preconditioned at various concentrations of remifentanil for 1 h, followed by 24-h lipopolysaccharide (LPS) exposure. MTT assays were performed to assess the cell viability in each group. The effects of remifentanil on factors related to uterine contractions in amniotic epithelial cells were assessed using a nitric oxide (NO) assay, western blot examinations of the expression of nuclear factor-kappa B (NF-κB), cyclooxygenase 2 (COX2), and prostaglandin E2 (PGE₂), and RT-PCR examinations of the expression of the proinflammatory cytokines interleukin (IL)-1β and tumor necrosis factor-alpha (TNF-α).

Results

Remifentanil did not affect viability and nitric oxide production of amniotic epithelial cells. Western blot analysis revealed that remifentanil preconditioning resulted in decreased expressions of NF-κB and PGE₂ in the cells in LPS-induced inflammation, and a tendency of decreased COX2 expression. The results were statistically significant only at high concentration. RT-PCR revealed reduced expressions of IL-1β and TNF-α.

Conclusions

Preconditioning with remifentanil does not affect the viability of amniotic epithelial cells but reduces the expression of factors related to uterine contractions in situations where cell inflammation is induced by LPS, which is an important inducer of preterm labor. These findings provide evidence that remifentanil may inhibit preterm labor in clinical settings.

Anesthetic management of abdominal radical trachelectomy for uterine cervical cancer during pregnancy

Abdominal radical trachelectomy has been identified as a surgical option for fertility preservation in cervical cancer patients, particularly in pregnant women who strongly desire to continue their pregnancy. Since this procedure requires operating in the uterus, the hardness of the uterus can affect the ease of surgery. Generally, sevoflurane is used for anesthesia in non-obstetric surgery for pregnant women because uterine relaxation is advantageous for uterine blood flow maintenance. However, the use of sevoflurane during radical trachelectomy has not been thoroughly evaluated. Here, we report on anesthesia use in three cases of abdominal radical trachelectomy during pregnancy. Propofol enabled maintenance of uterine tension while not significantly affecting fetal growth. It is important to consider maintenance of uterine tension and fetal circulation in anesthesia management. During the operation, we performed an ultrasound examination every 30 min to confirm fetal well-being. Although frequent fetal heart rate monitoring of the pre-viable fetus is not recommended, if fetal bradycardia is detected, sevoflurane may then be used to improve fetal circulation. Additionally, if the fetal heartbeat stops, a radical hysterectomy would then be required. Therefore, we consider that fetal heart rate monitoring during this procedure is necessary, and propofol is suitable as an anesthetic for this surgery during pregnancy.

Uterine and Abdominal Muscle Electromyographic Activities in Control and PCEA-Treated Nulliparous Women During the Second Stage of Labor

OBJECTIVE

Patient-controlled epidural analgesia (PCEA), used to relieve pain during delivery, delays labor but the mechanism is unknown. The aim was to investigate the effects of PCEA on uterine and abdominal muscles electromyographic (EMG) activity during the second stage of labor.

METHODS

This study included 45 nulliparous pregnant women without PCEA, 42 women with standard PCEA treatment given during the first stage of labor and stopped near the end of the first stage, and 22 women with standard PCEA treatment with continued use throughout the first and second stages of labor. The EMG signals were recorded from the abdominal surface using PowerLab hardware and LabChart software (ADInstruments, New South Wales, Australia) and filtered to separate uterine and abdominal EMG. Various EMG burst parameters were obtained.

RESULTS

There are no differences ( P > .05) in the age, body mass index, fetal weight, and Apgar scores between the patients from the various groups. PCEA (both stopped and continued) inhibits ( P < .05) duration, number of bursts, and root mean square of uterine EMG. PCEA also produces statistically significant ( P < .001) reductions in abdominal EMG. The decrease in EMG activity is accompanied by a significant ( P < .001) prolongation of the second stage duration (PCEA continued = 95.08 ± 8.60 minutes, PCEA stopped = 79.39 ± 6.25 minutes, no PCEA = 61.00 ± 7.23 minutes).

CONCLUSION

PCEA suppresses uterine and abdominal muscle EMG during the second stage of labor but inhibition depends upon the treatment schedule. PCEA prolongs the duration of labor by inhibition of uterine and abdominal muscle and neural activity.

In Vitro Effects of Propofol on Gravid Human Myometrium

The aim of this study was to evaluate the direct effect of propofol (di-isopropyl phenol) on the contractile properties of gravid human uterine muscle.

Six specimens of uterine muscle were obtained from term parturients undergoing elective lower segment caesarean section. Small strips (1 × 2 x 12 mm) of muscle were prepared and suspended in an organ bath containing oxygenated Kreb's solution at 36.5°C. Following preparation, spontaneous regular contractions developed at a rate of one contraction every six to 10 minutes. Force of contraction was recorded continuously using an isometric tension transducer. Following baseline measurements, propofol was introduced into the bath at concentrations corresponding to 2 /μg/ml, 5 /μg/ml and 8 /μg/ml. The specimens were also exposed to intralipid in concentrations equivalent to that found in the 8 μ/ml solution of propofol to determine whether this additive influenced uterine contractility. Contractility (defined as area under the tension/time curve) was decreased to 89 ± 6.5% of control at 2 μg/ml 53±4.3% at 5 μ/ml and 45 ± 4.1% at 8 μg/ml. This decrease in contractility was statistically significant at concentrations >2 μg/ml. Intralipid did not significantly affect uterine contractility. The results of this study show that propofol decreases isolated human uterine muscle contractility in a dose-dependent manner.

Reproductive emergencies in camelids

Emergencies in theriogenology practice go beyond just saving the life of the patient, but also preserving its reproductive abilities. Camelid emergency medicine is a relatively new field. This paper discusses the most common reproductive emergencies, their diagnosis, treatment, and prognosis in male and female camelids. The conclusions drawn are based primarily on clinical observations by the authors over the last 25 years. Special consideration is given to peculiarities of the species, particularly in the choice of obstetrical manipulations and therapies.

The extracorporeal perfusion of the swine uterus as an experimental model: The effect of tocolytic drugs

OBJECTIVE

Comparison of the effect of tocolytic drugs on isolated swine uterus preparations.

STUDY DESIGN

Forty swine uteri were perfused with the aim to preserve a viable organ, which should be responsive to oxytocic hormones and tocolytic pharmaca. An intrauterine catheter recorded the pressure changes. After initiation of rhythmical uterine contractions we administered known tocolytic drugs (fenoterol, ritodrine, terbutaline, propofol, acetylsalicylic acid, alcohol, atosiban, verapamil, and glyceryl trinitrate) in various concentrations.

RESULTS

Perfusate pH and lactate, partial oxygen and carbon dioxide tensions, and oxygen saturation in the perfusate showed good preservation of the organ for up to 8h. All substances showed a tocolytic effect on the swine uterus. The effect varied substantially with regard to the length of the contraction free intervals, which was our main effect parameter. Fenoterol, acetylsalicylic acid, and alcohol showed the most and glyceryl trinitrate the least powerful effect.

CONCLUSIONS

A direct comparison of various tocolytic substances in the same experimental model showed the best effect for fenoterol. Furthermore, we could demonstrate that the swine uterus perfusion system is a suitable model to study the influence of various conditions like the administration of drugs or the induction of oxidative stress on the uterus function.

À propos de trois grossesses consécutives chez une patiente cirrhotique

We report the case of a patient suffering from an immune liver cirrhosis with chronic liver insufficiency and a portal hypertension, presenting with three consecutive pregnancies. During the first pregnancy, stillbirth occurred at 34 weeks gestation (WG) with a justified vaginal delivery. There was no liver deterioration during the second pregnancy until 36 WG when fetal distress occurred, requiring a caesarean section under general anaesthesia. During the third pregnancy, fetal distress and maternal hepatic failure occurred at 35 WG, requiring an emergency caesarean section complicated with post partum haemorrhage and an episode of encephalopathy.

Effects of Propofol-Sevoflurane Anesthesia on the Maternal and Fetal Hemodynamics Blood Gases, and Uterine Activity in Pregnant Goats

To determine the effects of propofol and sevoflurane on hemodynamics, acid-base balance and uterine activity in pregnant animals, a prospective experimental study was designed by use of ten pregnant goats. Propofol was intravenously administered at a bolus dose of 5 mg/kg and then infused a rate of 0.3 mg/kg/min for 5 min. Following the induction, the animals were incrementally inhaled 2.7 and 4.1% of end-tidal concentration of sevoflurane each for 30 min, and then recovered. The maternal and fetal heart rate (HR), arterial blood pressure (BP) and acid-base balance, the intrauterine pressure (IUP), and the uterine blood flow (UBF) were measured. Following the pre-anesthetic data, the parameters were measured 7 times throughout the anesthetic and recovering periods. The propofol infusion induced 1.37 times of HR increase and produced decrease in PO(2) and a relevant metabolic acidemia in the mother, with no effect in the fetus. Sevoflurane reduced BP in the fetus from 30 (2.7%) to 60 (4.1%) min of inhalation. The uterine contractions disappeared throughout sevoflurane inhalation, and then recurred within 15 min after the cessation of sevoflurane. Propofol injection increases HR, and induces a moderate hypoxemia and metabolic acidemia associated with the suppressed ventilation for pregnant goats, with less effect on the fetal hemodinamics. Sevoflurane causes minimal change in maternal hemodynamics, but induces significant hypotension in the fetus and reduction of uterine activity. These data may be useful in making anesthetic choices combined with analgesia for Caesarian section in goats.

The role of K(+) channels on the inhibitor effect of sevoflurane in pregnant rat myometrium

Volatile anesthetics and K(+) channel openers inhibit spontaneous contractions in myometrial smooth muscle. Volatile anesthetics modulate K(+) channel activity. We investigated the role of two K(+) channel blockers on the effect of sevoflurane in pregnant rat myometrium. Term pregnant rat uteri were excised, and cross-sectional myometrial strips were mounted for isometric force recording. Sevoflurane inhibited the amplitude and frequency of spontaneous myometrial contractions in a concentration-dependent manner. The maximal inhibition measured in amplitude and frequency of spontaneous myometrial contractions with sevoflurane (at 3 minimum alveolar anesthetic concentration) was 44.32% and 33.32% of control contractions, respectively. Tetraethylammonium (TEA) and glibenclamide, K(+) channel blockers, increased spontaneous myometrial contractions in a concentration-dependent manner. Sevoflurane responses were repeated at concentrations with no effect on spontaneous contractility of TEA, a Ca(2+)-activated K(+) channel blocker, and glibenclamide, an adenosine triphosphate-sensitive K(+) channel blocker, in myometrial strips. TEA (3.10(-4) M) caused a significant reduction in sevoflurane-induced inhibitor responses, but glibenclamide (10(-6) M) did not. Sevoflurane-induced maximal inhibition (at 3 minimum alveolar anesthetic concentration) on amplitude and frequency of spontaneous myometrial contractions in the presence of TEA (3.10(-4) M) was 31.85% and 22.33% of control contractions, respectively (P < 0.05). These results suggest that the in vitroapplication of sevoflurane inhibited the amplitude and frequency of spontaneous myometrial contractions in pregnant rats in a concentration-dependent manner. Such inhibition was reduced by TEA. The inhibition of myometrial smooth muscle induced by sevoflurane seems to be mediated, at least in part, via activation of Ca(2+)-activated K(+) channels, because inhibition was reduced by TEA.

IMPLICATIONS

In this study, we found that sevoflurane causes significantly decreased myometrial contractile activity in pregnant rats. The inhibition of myometrial smooth muscle induced by sevoflurane seems to be mediated, at least in part, via activation of Ca(2+)-activated K(+) channels, because inhibition was reduced by tetraethylammonium.

Pharmacological considerations during pregnancy

We present a brief overview of recent literature concerning some of the drugs used in pregnancy, labour and delivery. Obstetric anaesthesia continues to evolve through the reuse of old drugs such as magnesium sulphate or the manipulation of current drugs (e.g. propofol for emesis) in order to improve patient outcome. Pregnant women have traditionally been therapeutic orphans. The use of new agents such as levobupivacaine and ropivacaine in obstetric patients lags behind that of their non-pregnant counterparts. However, this gap is decreasing and these new drugs offer benefits to the parturient woman.

The effects of opioids on isolated human pregnant uterine muscles

We determined the effects of fentanyl, sufentanil, morphine, and meperidine on the spontaneous contractility of isolated human pregnant uterine muscle strips. Uterine specimens were obtained from normal full-term parturients undergoing elective lower-segment cesarean delivery. Longitudinal muscle strips were prepared and mounted vertically in tissue chambers to record their isometric tension. Opioid concentration-response curves were constructed after rhythmic contractions were established. The responses were also examined in the presence of opioid receptor blocker, nitric oxide synthase inhibitor, beta-adrenoceptor blocker, or cyclooxygenase inhibitor. Fentanyl and meperidine inhibited uterine contractility in a concentration-dependent manner, their concentration that inhibited 50% being 2.3 x 10(-6) and 1.0 x 10(-3)M, respectively. Sufentanil and morphine had no significant effects on uterine contractility. Pretreatment with either naloxone, N(G)-nitro-L-arginine methyl ester, atenolol, or indomethacin did not affect the uterine responses to opioids. These results demonstrate that fentanyl and meperidine may have direct inhibitory effects on the contractility of the human uterus, though at supraclinical concentrations.

IMPLICATIONS

Opioids do not have a significant effect on spontaneous contractions of gravid human uterine muscle at their clinically relevant concentrations.