Neuraxial anesthesia and postoperative opioid administration for cesarean delivery in patients with placenta accreta spectrum disorder: a retrospective cohort study

BACKGROUND

There is no consensus on optimal anesthetic and analgesic management of patients presenting for cesarean delivery with suspected placenta accreta spectrum disorder. Neuraxial anesthesia is preferred for uncomplicated procedures, but general anesthesia may be indicated for those at risk of hemorrhage and hysterectomy. We compared the effect of anesthesia techniques on postoperative maternal opioid administration and neonatal respiratory distress.

METHODS

A single-center retrospective study from 2016 to 2019 using electronic records to identify singleton pregnancies with a high index of suspicion of placenta accreta spectrum disorder. Patients were categorized by the anesthetic technique they received: general, neuraxial, or neuraxial with conversion to general anesthesia following delivery. Postoperative maternal opioid administration (oral morphine in mg equivalents) and risk of neonatal respiratory distress were compared using linear mixed models.

RESULTS

Thirty-nine records were analyzed. Mean-adjusted oral morphine mg equivalents were 192 for patients receiving general anesthesia vs. 90 for neuraxial anesthesia only (P=0.009) and 104 for neuraxial with conversion to general anesthesia (P=0.052). Neonates delivered under general anesthesia had a 3.5 times relative risk (95% CI 1.3 to 9.8, P=0.017) of respiratory distress compared with those exposed to neuraxial anesthesia alone.

CONCLUSION

Patients receiving general anesthesia alone were administered more opioids than those undergoing neuraxial anesthesia or neuraxial with conversion to general anesthesia. This finding was maintained when accounting for whether or not the patient underwent hysterectomy. Deciding on anesthetic management requires consideration of patient comorbidities, severity of placenta accreta spectrum pathology, and surgical requirements.

Combination of modified mixing technique and low frequency ultrasound to control the elution profile of vancomycin-loaded acrylic bone cement

OBJECTIVES

The objective of this study was to determine if combining variations in mixing technique of antibiotic-impregnated polymethylmethacrylate (PMMA) cement with low frequency ultrasound (LFUS) improves antibiotic elution during the initial high phase (Phase I) and subsequent low phase (Phase II) while not diminishing mechanical strength.

METHODS

Three batches of vancomycin-loaded PMMA were prepared with different mixing techniques: a standard technique; a delayed technique; and a control without antibiotic. Daily elution samples were analysed using flow injection analysis (FIA). Beginning in Phase II, samples from each mix group were selected randomly to undergo either five, 15, 45, or 0 minutes of LFUS treatment. Elution amounts between LFUS treatments were analysed. Following Phase II, compression testing was done to quantify strength. A-priori t-tests and univariate ANOVAs were used to compare elution and mechanical test results between the two mix groups and the control group.

RESULTS

The delayed technique showed a significant increase in elution on day one compared with the standard mix technique (p < 0.001). The transition point from Phase I to Phase II occurred on day ten. LFUS treatments significantly increased elution amounts for all groups above control. Delayed technique resulted in significantly higher elution amounts for the five-minute- (p = 0.004) and 45-minute- (p < 0.001) duration groups compared with standard technique. Additionally, the correlations between LFUS duration and total elution amount for both mix techniques were significant (p = 0.03). Both antibiotic-impregnated groups exhibited a significant decrease in offset yield stress compared with the control group (p < 0.001), however, their lower 95% confidence intervals were all above the 70 MPa limit defined by International Standards Organization (ISO) 5833-2 reference standard for acrylic bone cement.

CONCLUSION

The combination of a delayed mix technique with LFUS treatments provides a reasonable means for increasing both short- and long-term antibiotic elution without affecting mechanical strength.Cite this article: Dr. T. McIff. Combination of modified mixing technique and low frequency ultrasound to control the elution profile of vancomycin-loaded acrylic bone cement. Bone Joint Res 2016;5:26-32. doi: 10.1302/2046-3758.52.2000412.

Transfusion has no effect on recurrence in hepatitis C after liver transplantation

BACKGROUND

The literature suggests that blood product transfusions have a negative impact on the survival of liver transplant patients. We investigated the impact of intraoperative blood product usage on the survival of liver transplantation patients being transplanted for hepatitis C-related end-stage liver disease. In addition, we analyzed a potentially more sensitive metric, namely disease recurrence and fibrosis progression, obtained from follow-up liver biopsies.

METHODS

We retrospectively studied 194 consecutive patients with hepatitis C virus (HCV) undergoing liver transplantation. To investigate the effect of red blood cell (RBC) or platelet transfusions on post-transplant HCV recurrence, hepatic biopsy data from 4 months and 1 year after transplantation were studied. In addition, survival data were analyzed.

RESULTS

There was no effect of intraoperative RBC or platelet transfusion on either 1- or 5-year patient survival following liver transplantation. There was no difference in HCV disease recurrence or progression of hepatic fibrosis at 4 months or 1 year attributable either to RBC or to platelet transfusion.

CONCLUSION

This study was not able to confirm an effect on the survival of HCV-infected liver transplant patients related to intraoperative transfusion of RBCs or platelets. In addition, these transfusions had no effect on HCV recurrence or fibrosis progression. This is not to condone a liberal transfusion practice, but rather to reassure that when clinically indicated, transfusion does not have a significant impact on patient survival or disease recurrence in HCV-infected liver transplant patients.

Effect of exogenous thyroxine on timing of seasonal reproductive transitions in ewes

The thyroid gland is necessary for the transition from the breeding season to anestrus in the ewe, but the importance of seasonal changes in thyroxine in this process is not known. The objective of this experiment was to determine the effects of exogenous thyroxine during the breeding season on the time of the transition to anestrus and on the onset of the subsequent breeding season in ewes maintained on natural photoperiod. Cyclic Galway ewes were blocked on the basis of body weight and randomly allocated to the following groups: 1) untreated controls (n = 11), 2) placebo-injected controls (n = 9), and 3) ewes injected daily with thyroxine from the middle of the breeding season until the onset of anestrus (n = 10). Reproductive state was assessed from serum progesterone concentrations determined twice weekly until the breeding season had ended in placebo-injected controls, and until the onset of the subsequent breeding season in untreated and thyroxine-injected ewes. The mean (+/- SEM) date of onset of anestrus did not differ between untreated ewes (April 19 +/- 9 days) and placebo-injected controls (April 15 +/- 9 days; p > 0.05), but occurred earlier in ewes injected with thyroxine (February 28 +/- 6 days; p < 0.001). Thyroxine treatment during the breeding season, however, did not affect the onset of the subsequent breeding season. These data indicate that supplementary thyroxine during the breeding season can advance anestrus and thus shorten the duration of the breeding season.(ABSTRACT TRUNCATED AT 250 WORDS)