None listed
Conditions
Brief summary
Opioids are considered as the gold standard for achieving good anesthetic action. However, opioids are usually avoided at the induction of general anesthesia for caesarean delivery until the delivery of newborn because of the risk of placental transfer and neonatal respiratory depression. The absence of opioids can cause a lack of analgesia. Moreover, insufficient anesthesia is manifested by exaggerated response to painful stimulus with increased catecholamine levels in the blood resulting in increased blood pressure, heart rate, intracranial pressure and decreased uteroplacental blood flow. This effect may be particularly risky in pregnant women with hypertension, chronic or gestational, including preeclampsia for a high risk of cerebrovascular accident. Consequences of hypertension can results even in malignant arythmia, pulmonary edema and hypoxia of the newborn One of the best suited opioid for providing labor analgesia using a systemic approach could be remifentanil. Remifentanil has a small volume of distribution with a rapid redistribution phase , and a short elimination half-life. Remifentanil quickly transfers across the placenta with a mean umbilical vein to maternal artery concentration ratio, but it is metabolized rapidly by nonspecific plasma and tissue esterases in the fetus and thus should not produce neonatal depression. This pharmacokinetic profile gives remifentanil an advantage over other opioids. P-glycoprotein (P-gp), which is highly expressed in the maternal-facing apical membrane of the syncytiotrophoblast, plays an important role in drug transfer across the placental barrier icluding opioids. Genetic polymorphisms are believed to be a major cause of the varaibility of its activity. Of particular interest are three SNPs C3435T in exon 26, and G2677T/A in exon 21 and the linkage between them. Another possible source of interindividual variability in the reaction to opioids including remifentanil are polymorphisms of OPRM1 gene coding mu-opioid receptor. There is great interest in one common polymorphism of OPRM1, p. A118G.
Interventions
Patients will receive an intravenous bolus of remifentanil once 30 s before the introduction into general anaesthesia. The dosage will be calculated according to start body weight of patient. Induction of anaesthesia will be performed with intravenous thiopental 5mg kg-1. Trachea will be intubated after muscle paralysis with intravenous suxamethonium 75-125 mg, with intravenous atracurium 0,35 mg kg-1 administered to achieve further muscle ralaxation. Anaesthesia will be maintained with inhalati
Patients will receive an intravenous bolus of remifentanil once 30 s before the introduction into general anaesthesia. The dosage will be calculated according to start body weight of patient. Induction of anaesthesia will be performed with intravenous thiopental 5mg kg-1. Trachea will be intubated after muscle paralysis with intravenous suxamethonium 75-125 mg, with intravenous atracurium 0,35 mg kg-1 administered to achieve further muscle ralaxation. Anaesthesia will be maintained with inhalation of sevoflurane 0,7 vol % in combination with 50 % nitrous oxide in oxygen, until the time of delivery. After birth and umbilical cord ligation intravenous sufentanil 0,3-0,5 mg kg-1, as required, inhalated nitrous oxide in oxygen (50/50 %, v/v) and inhalated sevoflurane (0,7-1 %) will be administered to achieve adequate sedation and analgesia till the end of surgery. Standart monitoring included non-invasive blood pressure measurement, pulse oximetry (SpO2), capnography, inspired oxygen fraction, electrocardiography (heart rate, ST segment trending), inspired and expired gas fraction. The bispectral index (BIS) values will be also monitored and observation values will be noted at 2.5 min intervals during 15 minutes. Time note will be taken of the following events: transfer to operation hall, administration of remifentanil, laryngoscopy and endotracheal intubation, skin incision, uterine incision, delivery, the end of the operation and extubation. Neonates will be assessed by using Apgar scores, possible respiratory depression. Exclusion criterias will be multiparity, gestational age < 35 weeks, estimated fetal weight < 2500g, hypoxia or signs of fetal stress and mother´s hypotension.
Sponsors
Interni grantove agentury Ministerstva zdravotnictvi (IGA)
Study design
Allocation
Randomised controlled trial
Primary purpose
Treatment
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
cesarean section, hypertension, preeclampsia
Exclusion criteria
multiparity, gestational age < 35 weeks, estimated fetal weight < 2500g, hypoxia or signs of fetal stress and mother´s hypotension
Outcome results
None listed