Effect and Placental Transfer of Dexmedetomidine During Caesarean Section Under General Anaesthesia

Fighting ferroptosis: Protective effects of dexmedetomidine on vital organ injuries

Vital organ injury is one of the leading causes of global mortality and socio-economic burdens. Current treatments have limited efficacy, and new strategies are needed. Dexmedetomidine (DEX) is a highly selective α2-adrenergic receptor that protects multiple organs by reducing inflammation and preventing cell death. However, its exact mechanism is not yet fully understood. Understanding the underlying molecular mechanisms of its protective effects is crucial as it could provide a basis for designing highly targeted and more effective drugs. Ferroptosis is the primary mode of cell death during organ injury, and recent studies have shown that DEX can protect vital organs from this process. This review provides a detailed analysis of preclinical in vitro and in vivo studies and gains a better understanding of how DEX protects against vital organ injuries by inhibiting ferroptosis. Our findings suggest that DEX can potentially protect vital organs mainly by regulating iron metabolism and the antioxidant defense system. This is the first review that summarizes all evidence of ferroptosis's role in DEX's protective effects against vital organ injuries. Our work aims to provide new insights into organ therapy with DEX and accelerate its translation from the laboratory to clinical settings.

Acute Respiratory Failure in Pregnancy

Respiratory failure may affect up to 1 in 500 pregnancies, due to pregnancy-specific conditions, conditions aggravated by the pregnant state, or other causes. Management during pregnancy is influenced by altered maternal physiology, and the presence of a fetus influencing imaging, and drug therapy choices. Few studies have addressed the approach to invasive mechanical ventilatory management in pregnancy. Hypoxemia is likely harmful to the fetus, but precise targets are unknown. Hypocapnia reduces uteroplacental circulation, and some degree of hypercapnia may be tolerated in pregnancy. Delivery of the fetus may be considered to improve maternal respiratory status but improvement does not always occur.

Application of Dexmedetomidine in Epidural Labor Analgesia: A Systematic Review and Meta-Analysis on Randomized Controlled Trials

OBJECTIVES

To summarize and appraise the use of dexmedetomidine in epidural labor analgesia, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

We conducted the literature search about the RCTs of epidural labor analgesia with or without dexmedetomidine from inception until November 1, 2022, in the following databases: PubMed, Cochrane Library, and Embase. The primary outcome was visual analog scale (VAS) within 2 hours after epidural intubation. The secondary outcomes included the duration of the first and second labor stages, Apgar score, umbilical blood pH, dosage of analgesics, and side effects.

RESULTS

Eight RCTs including 846 parturients were included. The VAS score of the dexmedetomidine group was significantly lower than that of the control group at the time of 15 minutes (mean difference [MD] -1.41, 95% confidence interval [CI] -2.23, -0.59), 30 minutes (MD -1.02, 95% CI -1.70, -0.33), 60 minutes (MD -0.90, 95% CI -1.36, -0.44), and 90 minutes (MD -0.70, 95% CI -1.16, -0.23). The incidence of pruritus in the dexmedetomidine group was lower than that of the control group （MD 0.28, 95% CI 0.11, 0.74), but the incidence of maternal bradycardia was higher (MD 6.41, 95% CI 1.64, 25.04). There were no significant difference in other outcomes.

DISCUSSION

Dexmedetomidine combined with local anesthetic for epidural labor analgesia can improve the VAS score of parturients. Except for the increased incidence of maternal bradycardia, it seems to be safe for the parturients and fetuses.

Perioperative Maternal-Fetal Outcomes in the Setting of Minimally Invasive Fetal Therapy for Complex Monochorionic Pregnancies with Monitored Anesthesia Care

INTRODUCTION

Fetoscopic selective laser photocoagulation (FSLPC) and selective cord occlusion with radiofrequency ablation (RFA) can improve fetal outcomes when vascular anastomoses between fetuses cause twin-to-twin transfusion syndrome (TTTS) or selective fetal growth restriction (sFGR) in multiple gestation pregnancies with monochorionic placentation. This study analyzed perioperative maternal-fetal complications and anesthetic management in a high-volume fetal therapy center over a 4-year period.

METHODS

Included patients received MAC for minimally invasive fetal procedures for complex multiple gestation pregnancies between January 1, 2015, and September 20, 2019. Maternal and fetal complications, intraoperative maternal hemodynamics, medication usage, and reasons for conversion to general anesthesia, if applicable, were analyzed.

RESULTS

A total of 203 (59%) patients underwent FSLPC and 141 (41%) had RFA. Four patients (2%; rate 95% CI: 0.00039, 0.03901) undergoing FSLPC had conversion to general anesthesia. No conversions to general anesthesia occurred in the RFA group. The incidence of maternal complications was higher in those who underwent FSLPC. No aspiration or postoperative pneumonia events were observed. Medication usage was similar in FSLPC and RFA groups.

CONCLUSION

A low rate of conversion to general anesthesia and no serious adverse maternal events were observed in patients receiving MAC.

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.

The Anesthetic Effect and Safety of Dexmedetomidine in Cesarean Section: A Meta-Analysis

Objective. To evaluate the anesthetic effect and safety of dexmedetomidine in cesarean section. Methods. The Cochrane Library, EMBASE, and PubMed databases (established until September 2020) were searched by computer. Two authors independently screened and extracted literature related to the application of dexmedetomidine in the cesarean section according to inclusion and exclusion criteria. The control group received either subarachnoid block (lumbar anesthesia) or combined lumbar anesthesia and epidural anesthesia (combined lumbar epidural anesthesia) with bupivacaine or combined bupivacaine and fentanyl. The observation group was additionally given dexmedetomidine based on the control group, to analyze the anesthetic effect and safety of dexmedetomidine in cesarean section. Results. A total of 580 cesarean delivery women were included in 8 studies, and the results showed that the peak time of sensory block in the observation group was shorter than that in the control group (standard mean $\text{difference}=-0.28$ ; 95% confidence interval: -0.48, -0.08; $P=0.006$ ), sensory block lasted longer than that in the control group (standard mean $\text{difference}=1.49$ ; 95% confidence interval: 1.21, 1.78; $P<0.00001$ ), the sedation rate was higher than that in the control group, the onset of the first postoperative pain was significantly delayed compared with that in the control group, and the incidence of postoperative pain, nausea and vomiting, postoperative chills, and fever was lower than that in the control group ( $P<0.05$ ). Conclusion. Dexmedetomidine combined with lumbar anesthesia or combined lumbar epidural anesthesia for women in cesarean section has more clinical benefits and better safety.

Effect of intravenous dexmedetomidine and remifentanil on neonatal outcomes after caesarean section under general anaesthesia: A systematic review and meta-analysis

BACKGROUND

Various strategies have been used to mitigate haemodynamic instability during general anaesthesia for caesarean section. However, the safety of these strategies for neonates remains controversial.

OBJECTIVE

To investigate the effects of intravenous dexmedetomidine and remifentanil on neonatal outcomes during caesarean section under general anaesthesia.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Databases of PubMed, EMBASE and CENTRAL were searched until March 2020 and updated in February 2021.

ELIGIBILITY CRITERIA

Randomised controlled trials were included if they compared dexmedetomidine and remifentanil infusion on neonatal outcomes after elective caesarean section under general anaesthesia. Primary outcomes were 1 and 5 min Apgar scores. Secondary outcomes were the incidence of neonatal mask ventilation or endotracheal intubation, and pH of the umbilical artery and vein. Studies that did not report primary outcomes were excluded.

RESULTS

Five studies with 258 patients in total were included. The Apgar score at 1 min in the remifentanil group was lower than that in the dexmedetomidine group for both quantitative [weighted mean difference (WMD): 0.75; 95% CI, 0.44 to 1.07; τ2 = 0.00] and categorical outcomes (≥Apgar 7 vs.

CONCLUSION

In our study, Apgar score at 1 min reported using both quantitative and categorical variables were lower in the remifentanil group than in the dexmedetomidine group but TSA showed that these differences were inconclusive for categorical variables. Data for other outcomes were scarce and did not allow any conclusions to be drawn. Thus, further studies with larger numbers of parturients and with neonatal outcomes as a primary endpoint are warranted to clarify the effects of intravenous dexmedetomidine and remifentanil.

TRIAL REGISTRATION

The protocol of this study has been registered in PROSPERO (CRD42019141102).

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MESH Headings

• Anesthesia, General/adverse effects
• Cesarean Section
• Dexmedetomidine/adverse effects
• Female
• Humans
• Infant, Newborn
• Piperidines/adverse effects
• Pregnancy
• Remifentanil

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Affiliation(s)

Myeongjong Lee From the Department of Anesthesiology and Pain Medicine (ML), Research Institute of Medical Science, Konkuk University School of Medicine, Chungju (ML), Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul (HK), Department of Anesthesiology and Pain Medicine, Wonkwang University School of Medicine, Muwang-ro, Iksan (CL) and Department of Anesthesiology and Pain Medicine, Chung-Ang University College of Medicine, Heukseok-ro, Dongjak-gu, Seoul, Republic of Korea (HK)
Hyungtae Kim
Cheol Lee
Hyun Kang

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Combination of Dexmedetomidine and Tramadol in Patient-Controlled Intravenous Analgesia Strengthens Sedative Effect in Pregnancy-Induced Hypertension

Objective: The aim of the present study is to explore the combination of dexmedetomidine (DXM) and tramadol (TMD) on sedative effect in patients with pregnancy-induced hypertension (PIH). Methods: A total of 356 patients with pregnancy-induced hypertension (PIH) were randomly divided into three groups: DXM, TMD and DXM + TMD groups. These patients were treated with different doses of DXM, TMD or combination of DXM and TMD by a patient-controlled intravenous injection device. The scores of static pain and dynamic pain, sedation degree, and adverse reaction were recorded. The plasma levels of inflammatory mediators IL-10 and C-reactive protein (CRP), and the serum level of p-p38-MAPK were evaluated. Results: It was found that administration with DXM 1.0 µg/kg/h + TMD 700 mg and DXM 2.0 µg/kg/h + TMD 600 mg result in stronger sedative effect than single administration with DXM or TMD. The mean arterial pressure (MAP) and heart rate (HR) of patients with PIH were decreased with the combinational treatment of DXM and TMD. Interestingly, the PIH patients injected with DXM 1.0 µg/kg/h + TMD 700 mg and DXM 2.0 µg/kg/h + TMD 600 mg showed stronger sedative effect. In addition, the plasma level of level of IL-10 was increased and CRP decreased. The serum level of p-p38/MAPK was decreased. Conclusion: Taken together, our study indicates that combination of DXM and TMD effectively lowers blood pressure and reduces inflammation through increasing the level of IL-10, reducing CRP and inhibiting p-p38/MAPK in patients with PIH. This study suggests that the combination of DXM and TMD could be an anesthetic choice in the management of PIH.

Dose Comparison of Dexmedetomidine Sedation following Spinal Anesthesia: Parturient versus Nonpregnant Women-A Randomized Trial

Background

This study was designed to investigate and compare the effective doses of dexmedetomidine for sedation in parturient patients who underwent Cesarean section (CS) and nonpregnant women who underwent elective gynecologic surgery.

Methods

The study comprised 60 females aged between 25 and 35. They were divided into two groups. The parturient group received a bolus dose of dexmedetomidine over 15 min after the delivery of the fetus and placenta. In the nonpregnant women group, a bolus of dexmedetomidine was administered intravenously upon the completion of spinal anesthesia. The subsequent dose required by patients in each group was then determined through a modified two-stage Dixon up-and-down sequential method. Probit analysis was used to calculate the ED50 and the ED95 of dexmedetomidine for adequate sedation.

Results

The ED50 of dexmedetomidine for adequate sedation in parturient patients was 1.58 μg/kg (1.51–1.66 μg/kg); in nonpregnant women, it was 0.96 μg/kg (0.91–1.01 μg/kg) (95% CI). The ED95 of dexmedetomidine in parturients was 1.80 μg/kg (1.70–2.16) μg/kg and that of nonpregnant women was 1.10 μg/kg (1.04–1.30 μg/kg) (95% CI). The ED50 in parturients was significantly higher than that in nonpregnant women (P < 0.05).

Conclusion

The ED50 of dexmedetomidine for target sedation in parturients who received spinal anesthesia for CS is greater than 1.5 times that in nonpregnant women who received spinal anesthesia for lower abdominal gynecologic surgery. This study postulates that the dose of dexmedetomidine required to achieve optimal sedation following spinal anesthesia is much higher in parturients than in nonpregnant women undergoing gynecologic surgeries. This trial is registered with NCT02111421.

Dexmedetomidine elevates the lethal dose threshold of bupivacaine in rats: A dosing study

Dexmedetomidine (DMED), an alpha-2 adrenoreceptor agonist, has been widely used in regional anesthesia procedures. However, the effect of DMED on local anesthetic cardiotoxicity has not been well delineated. This study consisted of two experiments. In experiment A, 42 Sprague–Dawley (SD) rats were randomly divided into 6 groups ( n = 7), each group was pretreated with DMED 0 μg kg−1 (D0 group), 1 μg kg−1 (D1 group), 3 μg kg−1 (D3 group), 6 μg kg−1 (D6 group), 12 μg kg−1 (D12 group), and 24 μg kg−1 (D24 group), administered through the right femoral vein. In experiment B, 20 SD rats were randomly divided into 4 groups ( n = 5), such as control group, DMED group, yohimbine (YOH) group, and DMED + YOH group. Each subgroup in experiment B was also pretreated similarly as in experiment A. After pretreatment of rats as described above (in experiments A and B), bupivacaine 2.5 mg kg−1 min−1 was infused to induce cardiac arrest. In experiment A, the lethal dose threshold of bupivacaine and plasma bupivacaine concentration in D3 and D6 group were higher than the other groups. In experiment B, there was no interaction between DMED and YOH in lethal dose threshold, arrhythmia time, plasma concentration of bupivacaine, and myocardial content of bupivacaine. DMED doses of 3–6 μg kg−1 elevated the lethal dose threshold of bupivacaine without involvement of the alpha-2 adrenoceptors.

Fetal and Maternal Responses to Dexmedetomidine Intrathecal Application During Cesarean Section: A Meta-Analysis

Background

Intrathecal dexmedetomidine (DEX) can improve the blockade of spinal anesthesia, but there is no clear conclusion on whether it has an effect on the fetus during cesarean section. Our meta-analysis evaluated the safety and efficacy of intrathecal DEX in cesarean delivery.

Material/Methods

We searched Cochrane, Embase, PubMed, and CBM for eligible studies, and used the Revised Cochrane Risk of Bias Tool (RoB 2.0) to assess the risk of bias of each study. RevMan was used for statistical analyses. We have registered this meta-analysis on PROSPERO (CRD42019120995).

Results

The meta-analysis included 10 RCTs, but only 5 were prospectively registered. The results of preregistration studies, including the 1- or 5-min Apgar score (mean difference [MD], −0.03; 95% confidence intervals [CI], −0.16 to 0.10; P=0.64 or MD, 0.00; 95% CI, −0.09 to 0.09; P=1), the umbilical arterial oxygen or carbon dioxide partial pressure (MD, 0.90; 95% CI, −4.92 to 6.72; P=0.76 or MD, 1.20; 95% CI, −2.06 to 4.46; P=0.47), and the cord blood pH (MD, −0.01; 95% CI, −0.05 to 0.03; P=0.72), showed that intrathecal DEX had no significant difference in neonatal outcomes compared with placebo. In maternal outcomes, intrathecal DEX significantly prolonged postoperative pain-free period and reduced the incidence of postoperative shivering, which did not increase spinal anesthesia-associated adverse effects.

Conclusions

Intrathecal DEX is safe for the fetus during cesarean section and can improve the blockade effects of spinal anesthesia on puerperae.

Effects of dexmedetomidine versus remifentanil on mothers and neonates during cesarean section under general anesthesia

BACKGROUND AND AIMS

Dexmedetomidine and remifentanil use in obstetric general anesthesia is controversial. This study aimed to compare the effects of remifentanil and dexmedetomidine on mothers and neonates during cesarean section under general anesthesia.

METHODS

A total of 120 patients scheduled for elective cesarean section under general anesthesia were randomly allocated to dexmedetomidine (D), remifentanil (R), and control (C) groups. Anesthesia was induced with propofol and muscle relaxants in all groups. Anesthesia in groups D and R was induced with dexmedetomidine (induction, 0.5 µg/kg; maintenance, 0.5 µg/kg.h) and remifentanil (induction, 0.5 µg/kg; maintenance, 2 µg/kg.h), respectively, until birth. Group C received equivalent volumes of normal saline. Mean arterial blood pressure (MAP), heart rate (HR), plasma catecholamine, visual analog pain score (VAS), and total tramadol consumption at 1, 2, and 3 hours after extubation were recorded. Neonatal effects were assessed by Apgar scores and umbilical blood gas analysis.

RESULTS

Post induction, MAP was significantly higher in group D compared to groups C and R, and significantly lower in group R than in group C. At intubation/skin incision and delivery, MAP, HR, and plasma epinephrine and norepinephrine concentrations were significantly lower in groups D and R than in group C. Compared to group R, MAP was significantly higher, and HR, plasma epinephrine, and norepinephrine concentrations were significantly lower in group D. Compared with groups C and D, the percentage of neonates with Apgar score < 7 was higher in group R at 1 min after delivery. Compared with groups C and R, the VAS was significantly lower in group D at 1 and 2 h postoperatively. Total tramadol consumption was significantly lower in group D at 3 hours postoperatively.

CONCLUSION

During general anesthesia for cesarean section, remifentanil demonstrated better control of hemodynamic stability, while dexmedetomidine demonstrated better neonatal Apgar scores, postoperative analgesia, and decreased catecholamine release.

TRIAL REGISTRATION

Chinese Clinical Trial Register (ChiCTR) - ChiCTR1800017125.

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.

Comparative evaluation of intrathecal bupivacaine alone and bupivacaine combined with dexmedetomidine in cesarean section using spinal anesthesia: a meta-analysis

Objective

This meta-analysis was performed to evaluate the effect of spinal anesthesia (SA) using bupivacaine combined with dexmedetomidine (DEX) in cesarean section, analyze the adverse drug reactions induced by this mixture, and provide a reference for rational drug use.

Methods

Randomized controlled trials were obtained from the PubMed, Cochrane Library, and Embase databases. The primary outcome measure was the time to the highest sensory block level (min), and the secondary outcome measure was adverse effects.

Results

The time to the highest sensory block level was significantly shorter in the bupivacaine-DEX group than in the control group (standardized mean difference, −0.23; 95% confidence interval, −0.43 to −0.03). The incidence of shivering during the process of anesthesia, especially at a dose of 5 µg DEX, was significantly lower in the bupivacaine-DEX group than in the control group (odds ratio, 0.26; 95% confidence interval, 0.14–0.49). No significant differences were observed in the symptoms of hypotension, bradycardia, nausea/vomiting, or pruritus.

Conclusion

Compared with the use of bupivacaine alone for SA in cesarean section, adding dexmedetomidine during SA can significantly shorten the onset time and decrease the rate of shivering during anesthesia.

Effectiveness and safety of intravenous application of dexmedetomidine for cesarean section under general anesthesia: a meta-analysis of randomized trials

Objective

The meta-analysis was conducted to assess the effectiveness and safety of intravenous administration of dexmedetomidine for cesarean section under general anesthesia, as well as neonatal outcomes.

Materials and methods

We searched PubMed, Embase, Cochrane Central Register of Controlled Trials and the China National Knowledge Infrastructure database for relevant randomized controlled trials (RCTs) about the application of intravenous dexmedetomidine under general anesthesia for cesarean section. RevMan 5.3 was used to conduct the meta-analysis of the outcomes of interest.

Results

Eight RCTs involved 376 participants were included in this study. The meta-analysis showed that the mean blood pressure at the time of intubation (weighted mean difference [WMD]: -15.67, 95% CI: -21.21, -10.13, P<0.00001), skin incision (WMD: -12.83, 95% CI -20.53, -5.14, P=0.001), and delivery (WMD: -11.65, 95% CI -17.18, -6.13, P<0.0001) in dexmedetomidine group were significantly lower than that in the control group. The heart rate (HR) at the time of intubation (WMD: -31.41, 95% CI -35.01, -27.81, P<0.00001), skin incision (WMD: -22.32, 95% CI -34.55, -10.10, P=0.0003), and delivery (WMD: -19.07, 95% CI -22.09, -16.04, P<0.00001) were also lower than that in control group. For neonatal parameters, no differences existed in umbilical blood gases at delivery, and Apgar scores at 1 minute (WMD: -0.12, 95% CI -0.37, 0.12, P=0.33) and 5 minutes (WMD: -0.17, 95% CI -0.13, 0.46, P=0.27) among two groups.

Conclusion

Intravenous administration of dexmedetomidine could efficiently attenuate the maternal cardiovascular response during cesarean section, without affecting Apgar score of the neonate.

Use of Dexmedetomidine in a Parturient With Multiple Endocrine Neoplasia Type 2A Undergoing Adrenalectomy and Thyroidectomy: A Case Report

Dexmedetomidine is a selective α2-agonist, frequently used in perioperative medicine as anesthesia adjunct. The medication carries a Food and Drug Administration pregnancy category C designation and is therefore rarely used for parturients undergoing nonobstetric surgery. We are reporting the use of dexmedetomidine in the anesthetic management of a parturient undergoing minimally invasive unilateral adrenalectomy for pheochromocytoma during the second trimester of pregnancy. Additionally, because of the multiple endocrine neoplasia type 2A constellation with diagnosis of medullary thyroid cancer, the patient underwent a total thyroidectomy 1 week after the adrenalectomy.

Impact of dexmedetomidine on hemodynamics in rabbits

PURPOSE

To evaluate the effects of single intravenous administration of Dexmedetomidine (DEX) on hemodynamics in rabbits.

METHODS

A total of 32 New Zealand white rabbits were randomly divided into the control group (Group C), Group D1 (2.75 μg/kg), Group D2 (5.5 μg/kg), and Group D3 (8.25 μg/kg) to compare systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), central venous pressure (CVP), left ventricular systolic pressure (LVSP), left ventricular end-stage diastolic pressure (LVEDP), left ventricular developmental pressure (LVDP), +dp/dtmax, -dp/dtmax, and t-dp/dtmax at different time points.

RESULTS

The levels of SBP, DBP, HR, LVSP, and LVEDP in Group D1, D2, and D3 were lower than that of Group C from T1 to T5 (P<0.05), but there was no significant difference at T6 and T7 (P>0.05). Compared with T0, the levels of SBP, DBP, HR, LVSP, LVEDP, and left arterial pressure (LAP) from T1 to T7 were decreased (P<0.05), but there was no significant difference in the other indexes (P>0.05).

CONCLUSION

Dexmedetomidine can decrease blood pressure and heart rate in rabbits in a dose-dependent manner, but there is no effect on the myocardial systolic and diastolic function.

Comparison of the effects of low doses of dexmedetomidine and remifentanil on the maternal hemodynamic changes during caesarean delivery in patients with severe preeclampsia: a randomized trial

BACKGROUND

Preoperative remifentanil administration blunts hemodynamic responses to tracheal intubation in parturients with severe preeclampsia. We hypothesized that the preoperative administration of low doses of remifentanil or dexmedetomidine would lead to comparable maternal neurohormonal responses and neonatal outcomes in patients with severe preeclampsia.

METHODS

Parturients diagnosed with severe preeclampsia undergoing caesarean delivery were randomLy allocated to receive remifentanil (0.1 µg/kg/min) or dexmedetomidine (0.4 µg/kg/h) at five min and 20 min before induction, respectively. Changes in maternal mean arterial BP(MAP), clinical recovery, cortisol level, and neonatal outcome, were recorded.

RESULTS

Patients who received remifentanil had higher response in MAP at the induction (94 9.8 vs. 104 4.5; P<0.001) and emergence from anesthesia (94 6.3 vs. 98 5.1; P<0.001), but shorter times to extubation (5.1 1.6 vs. 13.5 2.8 min; P<0.001). Five (27.8%) patients in the remifentanil group received ephedrine versus none in the dexmedetomidine group (P=0.023). The maternal plasma cortisol levels, the neonatal Neurologic and Adaptative Capacity Scores and acid-base satuses were similar in the two groups. Newborns in the remifentanil group presented lower Apgar scores at 1 minute (5.11 0.8 vs. 5.68 0.8; P=0.034) and a higher incidence of respiratory depression (72.2% vs. 36.8% P=0.048).

CONCLUSIONS

Compared with dexmedetomidine (0.4 µg/kg/h), the preoperative administration of remifentanil (0.1 µg/kg/min) produced a significantly higher effect on maternal hemodynamic responses to caesarean delivery in patients with severe preeclampsia, however maternal hypotension and neonatal respiratory depression were more common with the use of remifentanil.

Foetal responses to dexmedetomidine in parturients undergoing caesarean section: a systematic review and meta-analysis

Objective This current meta-analysis was conducted to evaluate effects of dexmedetomidine on neonatal maternal factors. Methods The electronic databases of PubMed, Embase, and Cochrane Central Register of Controlled Trials were searched. The primary outcomes were neonatal parameters, including umbilical blood gases and Apgar scores. The secondary outcomes were maternal parameters. Results We identified six randomized controlled trials (RCTs). No differences in neonatal umbilical blood gases, and Apgar scores at 1 min (WMD: -0.09; 95% CI: -0.21 to 0.04; I²= 0%) and 5 min (weighted mean difference (WMD): 0.03; 95% CI: -0.05 to 0.11; I²= 37%) were observed with dexmedetomidine. For maternal parameters, characteristics of motor and sensory block and postoperative analgesia (standard mean difference (SMD): 3.99; 95% CI: 2.85 to 5.12; I²= 78%) were significantly improved after dexmedetomidine treatment. Adverse events, including nausea/vomiting and shivering (risk ratio (RR): 0.26; 95% CI: 0.11 to 0.60; I²= 0%), were lower after dexmedetomidine treatment. Conclusion This meta-analysis shows that dexmedetomidine is safe for neonates who are delivered by caesarean section. Moreover, dexmedetomidine used in neuraxial anaesthesia can improve the characteristics of motor and sensory block and prolong the maternal pain-free period. Dexmedetomidine can also reduce the maternal incidence of postoperative adverse effects.

Effect and placental transfer of dexmedetomidine during caesarean section under epidural anaesthesia

Objective To investigate the neonatal effect and placental transfer of dexmedetomidine during caesarean section under epidural anaesthesia. Methods Forty parturients with a single newborn who were scheduled for caesarean section were enrolled. Patients received 0.5 µg/kg dexmedetomidine 10 min after epidural anaesthesia, followed by 0.5 µg/kg/h until abdominal closure (Dex group) or infusion of normal saline (NS group). Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were monitored before infusion (T0), 10 min after infusion (T1), at delivery (T2), and at the end of the operation (T3). Umbilical vein and artery blood was collected. Apgar scores were evaluated at 1 and 5 min after delivery. Results SBP, DBP, and HR in the Dex group were decreased at T3 compared with T0 (116 ± 10.4 vs 111 ± 9.2 mmHg, 74 ± 6.7 vs 66 ± 7.9 mmHg, 91 ± 12.1 vs 71 ± 8.4 beats/min, respectively, P < 0.05). HR was lower at T1, T2, and T3 in the Dex group compared with the NS group ( P < 0.05). There were no significant differences in blood gases and Apgar scores between the groups ( P > 0.05). Conclusion Dexmedetomidine during caesarean section under epidural anaesthesia is beneficial to parturients. The placental transfer rate is 0.68.

Postoperative management with dexmedetomidine in a pregnant patient who underwent AVM nidus removal: a case report

Background

Following cerebral arteriovenous malformation (AVM) surgery, severe brain edema and hemorrhage may be caused by postoperative normal perfusion pressure breakthrough (NPPB). Sedation is necessary for this population. It is a challenge for the anesthesiologist to maintain hemodynamic stability without interfering with the neurological assessment. In Japan, propofol is contraindicated for pregnant patients. Dexmedetomidine is a versatile drug in anesthesia practice and may be useful for this situation. There is no report using dexmedetomidine for the purpose of NPPB control in pregnant patients. We describe the postoperative management with dexmedetomidine for a pregnant patient who underwent cerebral AVM nidus removal.

Case presentation

A 32-year-old patient presented with headache at the 16th week of gestation. Neuroimaging revealed an intraventricular hemorrhage and an AVM at the right anterior horn of the lateral ventricle which caused bleeding. A multidisciplinary team discussion was done, and then a craniotomy for AVM nidus removal was performed under general anesthesia. Preanesthetic aspiration prophylaxis and rapid sequence induction were added to our conventional anesthetic management. Hypotension occurred after anesthetic induction but the patient recovered by volume resuscitation and vasopressors. Anesthesia was maintained with 50% O₂ in air and sevoflurane. The AVM was completely removed, and no perioperative complications occurred. Postoperative sedation with dexmedetomidine was used to prevent breakthrough hyperperfusion and cerebral edema.

Conclusions

Dexmedetomidine infusion was used for postoperative sedation without causing any side effects, and it can be an alternative for sedation, especially when propofol is contraindicated.