Intravenous lipid emulsion for local anaesthetic systemic toxicity in pregnant women: a scoping review

BACKGROUND

Local anaesthetic systemic toxicity (LAST) is a rare but life-threatening complication that can occur after local anaesthetic administration. Various clinical guidelines recommend an intravenous lipid emulsion as a treatment for local anaesthetic-induced cardiac arrest. However, its therapeutic application in pregnant patients has not yet been established. This scoping review aims to systematically identify and map the evidence on the efficacy and safety of intravenous lipid emulsion for treating LAST during pregnancy.

METHOD

We searched electronic databases (Medline, Embase and Cochrane Central Register Controlled Trials) and a clinical registry (lipidrescue.org) from inception to Sep 30, 2022. No restriction was placed on the year of publication or the language. We included any study design containing primary data on obstetric patients with signs and symptoms of LAST.

RESULTS

After eliminating duplicates, we screened 8,370 titles and abstracts, retrieving 41 full-text articles. We identified 22 women who developed LAST during pregnancy and childbirth, all presented as case reports or series. The most frequent causes of LAST were drug overdose and intravascular migration of the epidural catheter followed by wrong-route drug errors (i.e. intravenous anaesthetic administration). Of the 15 women who received lipid emulsions, all survived and none sustained lasting neurological or cardiovascular damage related to LAST. No adverse events or side effects following intravenous lipid emulsion administration were reported in mothers or neonates. Five of the seven women who did not receive lipid emulsions survived; however, the other two died.

CONCLUSION

Studies on the efficacy and safety of lipids in pregnancy are scarce. Further studies with appropriate comparison groups are needed to provide more robust evidence. It will also be necessary to accumulate data-including adverse events-to enable clinicians to conduct risk-benefit analyses of lipids and to facilitate evidence-based decision-making for clinical practice.

Maternal cardiopulmonary resuscitation

The perinatal resuscitation history in Japan is short, with the earliest efforts in the field of neonatology. In contrast, the standardization and dissemination of maternal resuscitation is lagging. With the establishment of the Maternal Death Reporting Project and the Maternal Death Case Review and Evaluation Committee in 2010, with the aim of reducing maternal deaths, the true situation of maternal deaths came to light. Subsequently, in 2015, the Japan Council for the Dissemination of Maternal Emergency Life Support Systems (J-CIMELS) was established to educate and disseminate simulations in maternal emergency care; training sessions on maternal resuscitation are now conducted in all prefectures. Since the launch of the project and council, the maternal mortality rate in Japan (especially due to obstetric critical hemorrhage) has gradually decreased. This has been probably achieved due to the tireless efforts of medical personnel involved in perinatal care, as well as the various activities conducted so far. However, there are no standardized guidelines for maternal resuscitation yet. Therefore, a committee was set up within the Japan Resuscitation Council to develop a maternal resuscitation protocol, and the Guidelines for Maternal Resuscitation 2020 was created in 2021. These guidelines are expected to make the use of high-quality resuscitation methods more widespread than ever before. This presentation will provide an overview of the Guidelines for Maternal Resuscitation 2020.

The RPOC long axis is a simple indicator for predicting the need of invasive strategies for secondary postpartum hemorrhage in either post-abortion or post-partum women: a retrospective case control study

Background

The retained products of conception (RPOC) and related conditions (RPOC-ARC) are the main cause of secondary postpartum hemorrhage (sPPH), but there is no clear consensus for their management. The purpose of this study was to characterize those RPOC-ARC that require invasive treatment and those that could be managed more conservatively.

Methods

We retrospectively analyzed 96 cases of RPOC-ARC that occurred after miscarriage, abortion, or delivery at a gestational age between 12 and 42 completed weeks, that were managed within our institution from May 2015 to August 2020. We reviewed the associations between the occurrence of sPPH requiring invasive treatment with clinical factors such as the maternal background and the characteristics of the lesions.

Results

The range of gestational age at delivery in our study was 12–21 weeks in 61 cases, 22–36 in 5, and 37 or later in 30. Among them, nine cases required invasive procedures for treatment. The onset of sPPH was within one month of delivery in all but two cases, with a median of 24 days (range 9–47). We found significant differences between requirements for invasive versus non-invasive strategies according to gestational age at delivery, assisted reproductive technology (ART) pregnancy, amount of blood loss at delivery, and the long axis of the RPOC-ARC lesion (p = 0.028, p = 0.009, p = 0.004, and p = 0.002, respectively). Multivariate analysis showed that only the long axis of the lesion showed a significant difference (p = 0.029). The Receiver Operating Characteristic (ROC) curve for predicting the need for invasive strategies using the long axis of the lesion showed that with a cutoff of 4.4 cm, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) was 87.5, 90.0, 43.8, and 98.7%, respectively.

Conclusion

The long axis of the RPOC-ARC is a simple indicator for predicting which sPPH will require invasive procedures, which use is rare in cases with lesions less than 4.4 cm or those occurring after the first postpartum month. Conservative management should be considered in such cases.

Case of uterine papillary serous carcinoma following tamoxifen treatment that could not be diagnosed during screening

This case involved a 69-year-old woman who had been taking tamoxifen for 5 years after breast cancer surgery. She was referred to our clinic for endometrial cancer screening when tamoxifen was first prescribed. Subsequently, transvaginal ultrasonography and endometrial cytology were performed every 6 months. Despite these regular examinations, stage IVb papillary serous carcinoma was detected 8 months after the end of tamoxifen administration. Total abdominal hysterectomy was performed, but only a small polyp was seen upon macroscopic examination of the uterus. However, papillary serous carcinoma was found microscopically in almost all lymphovascular spaces in the uterus from the endometrium to the serosa. On the surface of the polyp, only endometrial intraepithelial carcinoma with positive immunostaining for p53 was detected. Chemotherapy, including a platinum compound, was administrated, but unfortunately it was ineffective and the patient died of her disease 14 months after the operation.

[A case of poorly differentiated adenocarcinoma of the uterine cervix treated with paclitaxel and carboplatin after positive PAX 8 immunostaining]

PAX 8 is a paired-box gene that plays an important role in the embryogenesis of the thyroid gland, Müllerian ducts, and renal/upper urinary tract. PAX 8 expression is observed in carcinomas from each of these sites. Accordingly, PAX 8 immunostaining has been reported to be useful for the diagnosis of these carcinomas. Here, we report a case in which PAX 8 was useful for the diagnosis of a patient with cervical adenocarcinoma and multiple metastases. A 55-year-old female patient complained of cough and genital bleeding. Examination revealed a uterine cervical mass, masses in both breasts, and enlargement of the lymph nodes and subcutaneous nodules. Histology of the uterine cervical mass biopsy revealed a poorly differentiated adenocarcinoma. Cytology of the aspiration biopsy specimens of the breast masses indicated scirrhous cancer. PAX 8 immunostaining of the uterine cervical mass and breast mass biopsies was positive. We determined that the breast masses were metastases of the cervical adenocarcinoma and decided to treat the patient with chemotherapy consisting of paclitaxel and carboplatin. A partial response was observed. A hysterectomy was performed 5 months after chemotherapy because corpus cancer was newly diagnosed. The cervical adenocarcinoma was undetectable in the surgical specimen. Fifteen months have passed since the completion of chemotherapy and the metastases has been under control.

Isolation and characterization of a human alternative complement pathway-inhibiting protein from larval hemolymph of the silkworm, Bombyx mori

An alternative complement pathway-inhibiting protein (ACPIP), which inhibits the activation of the alternative complement pathway (ACP) of the human serum, was isolated from larval hemolymph of the silkworm, Bombyx mori, by using ammonium sulfate fractionation and column chromatographies to homogeneity. About 400microg of ACPIP was routinely obtained from 20ml hemolymph. The purified ACPIP preparation consisted of two distinct polypeptides (34 and 32kDa) on SDS-PAGE. The amino acid compositions of the two polypeptides were nearly identical; 21% of the amino acid residues were acidic. The amino terminal amino acid sequences up to 20 residues in these two polypeptides were also identical. Addition of the ACPIP to human serum resulted in a dose-dependent inhibition of the hemolysis of intact rabbit erythrocytes via the ACP, whereas in no inhibition of hemolysis of sensitized-sheep erythrocytes (EA) via the classical pathway.

Nonstandard peptide binding revealed by crystal structures of HLA-B*5101 complexed with HIV immunodominant epitopes

The crystal structures of the human MHC class I allele HLA-B*5101 in complex with 8-mer, TAFTIPSI, and 9-mer, LPPVVAKEI, immunodominant peptide epitopes from HIV-1 have been determined by x-ray crystallography. In both complexes, the hydrogen-bonding network in the N-terminal anchor (P1) pocket is rearranged as a result of the replacement of the standard tyrosine with histidine at position 171. This results in a nonstandard positioning of the peptide N terminus, which is recognized by B*5101-restricted T cell clones. Unexpectedly, the P5 peptide residues appear to act as anchors, drawing the peptides unusually deeply into the peptide-binding groove of B51. The unique characteristics of P1 and P5 are likely to be responsible for the zig-zag conformation of the 9-mer peptide and the slow assembly of B*5101. A comparison of the surface characteristics in the alpha1-helix C-terminal region for B51 and other MHC class I alleles highlights mainly electrostatic differences that may be important in determining the specificity of human killer cell Ig-like receptor binding.

Killer cell immunoglobulin receptors and T cell receptors bind peptide-major histocompatibility complex class I with distinct thermodynamic and kinetic properties

Human natural killer cells and a subset of T cells express a repertoire of killer cell immunoglobulin receptors (KIRs) that recognize major histocompatibility complex (MHC) class I molecules. KIRs and T cell receptors (TCRs) bind in a peptide-dependent manner to overlapping regions of peptide-MHC class I complexes. KIRs with two immunoglobulin domains (KIR2Ds) recognize distinct subsets of HLA-C alleles. Here we use surface plasmon resonance to study the binding of soluble forms of KIR2DL1 and KIR2DL3 to several peptide-HLA-Cw7 complexes. KIR2DL3 bound to the HLA-Cw7 allele presenting the peptide RYRPGTVAL with a 1:1 stoichiometry and an affinity (K(d) approximately 7 microM at 25 degrees C) within the range of values measured for other cell-cell recognition molecules, including the TCR. Although KIR2DL1 is reported not to recognize the HLA-Cw7 allele in functional assays, it bound RYRPGTVAL/HLA-Cw7, albeit with a 10-20-fold lower affinity. TCR/peptide-MHC interactions are characterized by comparatively slow kinetics and unfavorable entropic changes (Willcox, B. E., Gao, G. F., Wyer, J. R. , Ladbury, J. E., Bell, J. I., Jakobsen, B. K., and van der Merwe, P. A. (1999) Immunity 10, 357-365), suggesting that binding is accompanied by conformational adjustments. In contrast, we show that KIR2DL3 binds RYRPGTVAL/HLA-Cw7 with fast kinetics and a favorable binding entropy, consistent with rigid body association. These results indicate that KIR/peptide-MHC class I interactions have properties typical of other cell-cell recognition molecules, and they highlight the unusual nature of TCR/peptide-MHC recognition.