Inhibitory effects of desflurane and sevoflurane on oxytocin-induced contractions of isolated pregnant human myometrium

Management and Outcome of Women with Placenta Accreta Spectrum and Treatment with Uterine Artery Embolization

BACKGROUND

Placenta accreta spectrum (PAS) disorders are a continuum of placental pathologies with increased risk for hemorrhage, blood transfusion and maternal morbidity. Uterine artery embolization (UAE) is a safe approach to the standardization of complex PAS cases. The aim of this study is to analyze anemia and transfusion rate, outcome and anesthesiological management of women who underwent caesarean delivery with subsequent UAE for the management of PAS.

MATERIAL AND METHODS

This retrospective observational study included all pregnant women admitted to the University Hospital Frankfurt between January 2012 and September 2023, with a diagnosis of PAS who underwent a two-step surgical approach for delivery and placenta removal. Primary procedure included cesarean delivery with subsequent UAE, secondary procedure included placenta removal after a minim of five weeks via curettage or HE. Maternal characteristics, anesthesiological management, complications, anemia rate, blood loss and administration of blood products were analyzed.

RESULTS

In total, 17 women with PAS were included in this study. Of these, 5.9% had placenta increta and 94.1% had placenta percreta. Median blood loss was 300 (200-600) mL during primary procedure and 3600 (450-5500) mL during secondary procedure. In total, 11.8% and 62.5% of women received red blood cell transfusion during the primary and secondary procedures, respectively. After primary procedure, postpartum anemia rate was 76.5%. The HE rate was 64.7%. Regional anesthesia was used in 88.2% during primary procedure.

CONCLUSION

The embolization of the uterine artery for women diagnosed with PAS is safe. Anemia management and the implementation of blood conservation strategies are crucial in women undergoing UAE for the management of PAS.

Risk factors for severe postpartum hemorrhage requiring blood transfusion after cesarean delivery for twin pregnancy: a nationwide cohort study

BACKGROUND

Postpartum hemorrhage (PPH) is a leading cause of maternal morbidity and mortality. Twin pregnancy and cesarean delivery are well-known risk factors for PPH. However, few studies have investigated PPH risk factors in mothers who have undergone cesarean delivery for twin pregnancies. Therefore, this study investigated the risk factors associated with severe PPH after cesarean delivery for twin pregnancies.

METHODS

We searched and reviewed the Korean Health Insurance Review and Assessment Service's claims data from July 2008 to June 2021 using the code corresponding to cesarean delivery for twin pregnancy. Severe PPH was defined as hemorrhage requiring red blood cell (RBC) transfusion during the peripartum period. The risk factors associated with severe PPH were identified among the procedure and diagnosis code variables and analyzed using univariate and multivariate logistic regressions.

RESULTS

We analyzed 31,074 cesarean deliveries for twin pregnancies, and 4,892 patients who underwent cesarean deliveries for twin pregnancies and received RBC transfusions for severe PPH were included. According to the multivariate analysis, placental disorders (odds ratio, 4.50; 95% confidence interval, 4.09- 4.95; P < 0.001), general anesthesia (2.33, 2.18-2.49; P < 0.001), preeclampsia (2.20, 1.99-2.43; P < 0.001), hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome (2.12, 1.22-3.68; P = 0.008), induction failure (1.37, 1.07-1.76; P = 0.014), and hypertension (1.31, 1.18-1.44; P < 0.001) predicted severe PPH.

CONCLUSIONS

Placental disorders, hypertensive disorders such as preeclampsia and HELLP syndrome, and induction failure increased the risk of severe PPH after cesarean delivery for twin pregnancy.

The comparison of caesarean section bleeding between volatile and total intravenous anaesthesia in a Japanese nationwide database

BACKGROUND

Volatile anaesthesia may increase blood loss because of the uterine-relaxing effect of the volatile anaesthetics during caesarean section under general anaesthesia.

OBJECTIVE

This study compared the bleeding risk during caesarean section between volatile anaesthesia and total intravenous anaesthesia (TIVA) using a nationwide inpatient database in Japan.

DESIGN

Observational study.

SETTING

Nationwide inpatient database in Japan from April 2012 to March 2020.

PATIENTS

Women who underwent caesarean section under general anaesthesia.

MAIN OUTCOME MEASURES

Volume of blood loss.

RESULTS

We identified 26 585 women, including 19 320 in the volatile anaesthesia group (mean age = 32.9 ± 5.5 years) and 7265 in the TIVA group (mean age = 32.8 ± 5.5 years). The mean blood loss was 1113 ± 909 and 1136 ± 944 ml and the proportion of blood transfusion was 14.7 and 16.0% in the volatile and TIVA groups, respectively. With conventional regression analyses, volatile anaesthesia was associated with a slightly lower risk of bleeding: the adjusted mean difference for blood loss (95% CI) was -56.1 (-81.4 to -30.7). However, in the instrumental variable analysis, volatile anaesthesia was associated with a higher risk of bleeding: adjusted mean difference for blood loss (95% CI) was 154.3 (112.4 to 196.3) ml.

CONCLUSION

This large observational study with instrumental variable analyses suggested an increased bleeding risk associated with volatile anaesthesia, and the results were not identical to those in the conventional regression analyses.

The use of processed electroencephalography (pEEG) in obstetric anaesthesia: a narrative review

Accidental awareness under general anaesthesia (AAGA) remains a major complication of anaesthesia. The incidence of AAGA during obstetric anaesthesia is high relative to other specialities. The use of processed electroencephalography (pEEG) in the form of "depth of anaesthesia" monitoring has been shown to reduce the incidence of AAGA in the non-obstetric population. The evidence for using pEEG to prevent AAGA in the obstetric population is poor and requires further exploration. Furthermore, pregnancy and disease states affecting the central nervous system, such as pre-eclampsia, may alter the interpretation of pEEG waveforms although this has not been fully characterised. National guidelines exist for pEEG monitoring with total intravenous anaesthesia and for "high-risk" cases regardless of technique, including the obstetric population. However, none of the currently available guidelines relates specifically to obstetric anaesthesia. Using pEEG monitoring for obstetric anaesthesia may also provide additional benefits beyond a reduction in risk of AAGA. These potential benefits include reduced postoperative nausea and vomiting, reduced anaesthetic agent use, a shorter post-anaesthetic recovery stay. In addition, pEEG acts as a surrogate marker of cerebral perfusion, and thus as an additional monitor for impending cardiovascular collapse, as seen in amniotic fluid embolism. The subtle physiological and pathological changes in EEG activity that may occur during pregnancy are an unexplored research area in the context of anaesthetic pEEG monitors. We believe that the direction of clinical practice is moving towards greater use of pEEG monitoring and individualisation of anaesthesia.

Association between anesthetic method and postpartum hemorrhage in Korea based on National Health Insurance Service data

Background

Postpartum hemorrhage (PPH) is a major cause of maternal mortality and the risk factors for PPH differ among studies. In this large-scale study, we investigated whether the anesthetic method used was associated with PPH after cesarean section.

Methods

We extracted data on cesarean sections performed between January 2008 and June 2013 from the National Health Insurance Service database. The anesthetic methods were categorized into general, spinal and epidural anesthesia. To compare the likelihood of PPH among deliveries using different anesthetic methods, crude and adjusted odds ratios (ORs) and 95% confidence intervals were calculated using logistic regression analysis.

Results

Data from 330,324 cesarean sections were analyzed, and 21,636 cases of PPH were identified. Univariate analysis showed that general and epidural anesthesia increased the risk of PPH compared to spinal anesthesia. The OR for PPH was highest for morbidly adherent placenta, followed by placenta previa, placental abruption, and hypertension. When other clinical covariates were controlled for, general and epidural anesthesia still remained significant risk factors for PPH compared to spinal anesthesia.

Conclusions

This study showed that general and epidural anesthesia elevated the risk of PPH compared to spinal anesthesia during cesarean section. Since we could not consider the potential bias of group differences in indications, more in-depth clinical trials are needed to validate our findings. Obstetric factors such as placental abnormalities had high odds ratios and thus are more important than the choice of anesthetic method, which should be based on the patient's clinical condition and institutional resources.

General or regional anaesthesia for postpartum haemorrhage-A national population-based cohort study

BACKGROUND

Anaesthesia is required to assist the treatment of postpartum haemorrhage (PPH) when manual removal of the placenta or emptying of the uterine cavity is required. The choice between general or regional anaesthesia may depend upon factors such as existing epidural, airway, hypovolaemia, and tradition.

METHODS

Data from a randomized controlled trial of PPH (FIB-PPH) was used to reveal differences between delivery centres. In addition, national data of 5,601 PPH procedures requiring anaesthesia during 2010-2015 was collected from the Danish Medical Birth Registry, the National Danish Patient Registry, and the Danish Anaesthesia Database. The aim is to describe the variation in choice of anaesthesia for treatment of PPH.

RESULTS

Data from the randomized trial showed large differences in practice between centres not explained by physiological factors. Using national Danish registry data, we show that large delivery centres as compared to small centres prefer regional anaesthesia for PPH procedures in opposed to general anaesthesia. Sevoflurane was used despite it causing uterine relaxation. The use of general anaesthesia was associated with younger parturients, larger blood loss, and larger Body-Mass Index. Aspiration was recorded in one case (0.02%). In the postoperative care-unit general anaesthesia was associated with a shorter stay, but also higher pain score at admission.

CONCLUSION

Practice varies immensely between delivery centres with large centres preferring regional anaesthesia. Difference in practice might be explained by level of experience, here large centres might be more confident using regional anaesthesia. Knowledge is being extrapolated from literature on caesarean sections. Future studies should address the optimal choice of anaesthesia for PPH procedures.

Case Series: Video-Assisted Minimally Invasive Cardiac Surgery During Pregnancy

Surgical intervention is expected to improve maternal outcomes in pregnant patients with heart disease once the conservative treatment fails. For pregnant patients with heart disease, the risk of cardiac surgery under cardiopulmonary bypass (CPB) must be balanced due to the high fetal loss. The video-assisted minimally invasive cardiac surgery (MICS) has been progressively applied and shows advantages in non-pregnant patients over the years. We present five cases of pregnant women who underwent a video-assisted minimally invasive surgical approach for cardiac surgery and the management strategies. In conclusion, the video-assisted MICS is feasible and safe to pregnant patients, with good maternal and fetal outcomes under the multidisciplinary assessment and management.

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.

Clinical management of the pregnant patient undergoing non-obstetric surgery: Review of guidelines

The management principles of non-obstetric surgery during pregnancy are important concepts for all health care providers to be cognizant of. The goals of non-obstetric surgery are to ensure maternal safety, maintain the pregnancy, and ensure fetal well-being. In this regard, organogenesis occurs roughly between days 7-57 and thus, certain medications have a higher incidence of fetal teratogenicity in this first trimester. Some examples of common surgeries performed urgently or emergently include appendectomies, ovarian detorsions, bowel obstruction, trauma, and cholecystectomies. The choice of anesthetic technique and the selection of appropriate anesthetic drugs should be guided by indication for surgery, the nature of the surgery, and the site of the surgical procedure. Many of the concerns for any patients undergoing urgent or emergent surgery must be considered by anesthesia providers along with steps to ensure the fetus has the best outcome.

Awareness and Aortocaval Obstruction in Obstetric Anesthesia

Awareness during general anesthesia for cesarean delivery continues to be a major problem. The key to preventing awareness is strict attention to anesthetic technique. The prevalence and implications of aortocaval compression have been firmly established. Compression of the vena cava is a real occurrence when assuming the supine position. Relief of this compression most likely does not occur until the patient is turned 30°, which is not feasible for performing cesarean delivery. Although it is still wise to tilt the patient, the benefit of this tilt may not be as great as once thought.

[Clinical and pharmacological procedures for the prevention of postpartum haemorrhage in the third stage of labor]

OBJECTIVES

To describe the clinical and pharmacological procedures for the prevention of Postpartum Haemorrhage (PPH).

MATERIALS AND METHODS

We searched the Medline and the Cochrane Library (1st December 2004 to 1st March 2014) and we checked the international guidelines.

RESULTS

Vaginal birth: only the use of uterotonics reduces the incidence of PPH. Oxytocin is the treatment of choice if it is readily available (grade A). Oxytocin can be used either after the shoulders expulsion or rapidly after the placental delivery (grade B). A dose of 5 or 10IU must be administrated IV over at least 1minute or directly by an intramuscular injection (professional agreement) except in women with documented cardiovascular disease in which the duration of the IV perfusion should be over at least 5minutes (professional agreement). Mechanical procedures have no significant impact on PPH. The decision to use a collector bag is left to the medical team (professional agreement). A systematic complementary oxytocin perfusion is not recommended (professional agreement). Caesarean delivery: There is no evidence to recommend a particular type of caesarean technique to prevent PPH (professional agreement) but a lower uterine section is recommended (grade B). All types of incision expansion may be used (professional agreement). A controlled cord traction is associated with lower blood losses than manual removal of the placenta (grade B). A dose of 5 or 10IU can be injected (IV) over 1minute, and over 5minutes in women with cardiovascular disease (professional agreement). Carbetocin reduces the incidence of PPH but there is presently no inferiority study comparing oxytocin and carbetocin so that oxytocin remains the gold standard therapy to prevent PPH in C-section (professional agreement).

The effect of type of anesthesia on intra-and postoperative blood loss at elective cesarean section

BACKGROUND

In cesarean section (c-sec) it is known that women receiving spinal anesthesia have decreased intraoperative blood loss compared to women receiving general anesthesia. However, we should always consider postoperative bleeding (postpartum bleeding) that may follow. The amount of postpartum bleeding can be substantial. Therefore, we sought to evaluate the effect of type of anesthesia retrospectively on intra- and postoperative blood loss by comparing the changes of postoperative Hb, Hct at c-sec.

METHODS

We retrospectively compared the medical records of 287 elective c-sec patients. We excluded medical and obstetric conditions that may predispose such patients to increased blood loss. Subsequent detailed record analysis included 152 patients that received spinal anesthesia (group S), and 135 patients that received sevoflurane for general anesthesia (group G).

RESULTS

In comparison with the preoperative Hb, rates of Hb in the 1(st) postoperative day in group S significantly decreased compared to group G, but there was no significant difference in decreasing rates of Hb in the 3(rd) postoperative day between groups S and G. Estimated blood loss (EBL) of the intraoperative and operative day in group S was significantly lower compared to group G, but there was no significant difference in EBL of 1(st) and 2(nd) postoperative day between groups S and G.

CONCLUSIONS

We conclude that group S had a decrease in blood loss between the intraoperative and operative day and there was no significant differences in postoperative blood loss compared with group G.

The management of breakthrough pain during labour

There is a long history of attempts to alleviate the pain of childbirth, particularly in Asian and Middle Eastern civilisations. In the UK, it was the administration of chloroform to Queen Victoria by John Snow in 1853 that is widely credited with popularizing the idea that labour pain should and could be treated. Medical analgesia is now well established around the globe with a wealth of research evidence describing methods, efficacy and complications. In this article, we define 'primary breakthrough pain' as the moment when a woman first requests analgesia during labour. The management of this can include simple emotional support, inhaled analgesics, parenteral opioids and epidural analgesia. 'Secondary breakthrough pain' can be defined as the moment when previously used analgesia becomes ineffective. We concentrate our discussion of this phenomenon on the situation when epidural analgesia begins to fail. Only epidural analgesia offers the potential for complete analgesia, so when this effect is lost the recipient can experience significant distress and dissatisfaction. The best strategy to avert this problem is prevention by using the best techniques for epidural catheterisation and the most effective drug combinations. Even then, epidurals can lose their efficacy for a variety of reasons, and management is hampered by the fact that each rescue manoeuvre takes about 30 minutes to be effective. If the rescue protocol is too cautious, analgesia may not be successfully restored before delivery, leading to patient dissatisfaction. We therefore propose an aggressive response to epidural breakthrough pain using appropriate drug supplementation and, if necessary, the placement of a new epidural catheter. Combined spinal epidural techniques offer several advantages in this situation. The goal is to re-establish analgesia within 1 hour. The primary aim of pain management during labour and delivery is to provide the level of comfort determined as acceptable to each individual woman. Some require little or no analgesia, while others demand complete abolition of pain. Whatever the individual's personal point of breakthrough pain is, supporting clinicians should respond logically and rapidly to re-establish analgesia using locally agreed protocols. This approach will maximize patient satisfaction and hopefully increase the pleasure and satisfaction of childbirth.

Oxytocin pretreatment decreases oxytocin-induced myometrial contractions in pregnant rats in a concentration-dependent but not time-dependent manner

Recent biomolecular studies have shown that continuous exposure of human myometrial cells to oxytocin results in a significant loss of responsiveness to subsequent oxytocin stimulation, perhaps because of desensitization of the oxytocin receptors. However, it is unclear whether this phenomenon results in a reduction of the contractile activity of the uterine muscle in humans or animals. The objective of our study was to investigate the in vitro response of the uterine muscle of pregnant rats to oxytocin, following preexposure to varying concentrations of oxytocin, for varying durations. Longitudinal myometrial strips were isolated from 16 pregnant Wistar rats at 19 to 21 days of gestation and preexposed to oxytocin 10(-10) or 10(-8) mol/L (experimental groups) or physiological salt solution (control groups) for 1- or 4-hour period. All muscle strips were then subjected to a dose-response study with oxytocin 10(-10) to 10(-5) mol/L. The area under the curve, frequency, and amplitude of contractions were recorded and compared between the groups. The area under the curve, frequency, and amplitude of the oxytocin-induced contractions were all significantly suppressed in the groups preexposed to oxytocin 10(-8) mol/L compared to either the control groups (P < .0001) or the groups preexposed to oxytocin 10(-10) mol/L (P < .0001). There was no difference in the oxytocin-induced myometrial contractions between the groups preexposed to oxytocin for either the 1- or 4-hour periods. The inhibition of the oxytocin-induced contractile response of pregnant rat myometrium is observed as early as 1 hour of preexposure to oxytocin and is dependent on the preexposed oxytocin concentration and not on the duration of its exposure.

Inhibitory effect of alprostadil against sevoflurane-induced myometrial relaxation in rats

PURPOSE

For anesthetic management of cesarean sections, regardless of the use of regional or general anesthesia, it is crucial to achieve sufficient uterine contraction immediately following the delivery of an infant in order to reduce excessive bleeding. No previous study has investigated the ability of alprostadil, a synthesized prostaglandin, to inhibit myometrial relaxation induced by volatile anesthetics. The aim of the present study was to investigate the inhibitory effects of alprostadil on sevoflurane-induced myometrial relaxation using myometrial strips isolated from pregnant rats.

METHODS

Myometrial strips were isolated from Sprague-Dawley rats (300-400 g) in the late stage of gestation (19-21 days). The time course of changes in spontaneous myometrium contraction was studied in the presence and absence of sevoflurane. Additionally, alprostadil was titrated at three different concentrations during continuous introduction of sevoflurane 2%, and myometrium contraction was studied. As an index of contraction, the area under the contraction curve was used, and data were analyzed by repeated measure one-way analysis of variance.

RESULTS

We have shown a significant decrease in myometrium contraction as a result of the use of sevoflurane (2%). Additionally, alprostadil has been shown to inhibit myometrial relaxation induced by sevoflurane in a dose-dependent manner. The areas under the contraction curve were 87%, 87%, 129%, and 172% of the baseline value for the control and at low, medium, and high concentrations of alprostadil, respectively.

CONCLUSION

The ability of alprostadil to inhibit myometrial relaxation induced by sevoflurane suggests that the use of alprostadil during general anesthesia for cesarean section may be advantageous for the reduction of postpartum bleeding.