Neuraxial clonidine is not associated with lower post-cesarean opioid consumption or pain scores in parturients on chronic buprenorphine therapy: a retrospective cohort study

PURPOSE

Adequate post-cesarean delivery analgesia can be difficult to achieve for women diagnosed with opioid use disorder receiving buprenorphine. We sought to determine if neuraxial clonidine administration is associated with decreased opioid consumption and pain scores following cesarean delivery in women receiving chronic buprenorphine therapy.

METHODS

This was a retrospective cohort study at a tertiary care teaching hospital of women undergoing cesarean delivery with or without neuraxial clonidine administration while receiving chronic buprenorphine. The primary outcome was opioid consumption (in morphine milligram equivalents) 0-6 h following cesarean delivery. Secondary outcomes included opioid consumption 0-24 h post-cesarean, median postoperative pain scores 0-24 h, and rates of intraoperative anesthetic supplementation. Multivariable analysis evaluating the adjusted effects of neuraxial clonidine on outcomes was conducted using linear regression, proportional odds model, and logistic regression separately.

RESULTS

196 women met inclusion criteria, of which 145 (74%) received neuraxial clonidine while 51 (26%) did not. In univariate analysis, there was no significant difference in opioid consumption 0-6 h post-cesarean delivery between the clonidine (8 [IQR 0, 15]) and control (1 [IQR 0, 8]) groups (P = 0.14). After adjusting for potential confounders, there remained no significant association with neuraxial clonidine administration 0-6 h (Difference in means 2.77, 95% CI [- 0.89 to 6.44], P = 0.14) or 0-24 h (Difference in means 8.56, 95% CI [- 16.99 to 34.11], P = 0.51).

CONCLUSION

In parturients receiving chronic buprenorphine therapy at the time of cesarean delivery, neuraxial clonidine administration was not associated with decreased postoperative opioid consumption, median pain scores, or the need for intraoperative supplementation.

Effectiveness of Oral Iron Therapy in Anemic Inpatient Pregnant Women: A Single Center Retrospective Cohort Study

Background and aim Oral iron therapy is effective in treating iron deficiency anemia in outpatient pregnant women but has not been studied in inpatient pregnant women. We aimed to evaluate the effect of oral iron therapy versus no therapy during hospitalization on maternal and neonatal outcomes in women with anemia who are hospitalized for pregnancy-related morbidities (i.e., preterm premature rupture of membranes, preterm labor, pre-eclampsia, abnormal placentation, or fetal monitoring). Methods A retrospective, single-center study was conducted in hospitalized pregnant women (2018 to 2020) with inpatient stays of more than three days. The primary outcome was a change in hemoglobin level from admission to delivery in women treated with oral iron compared with those left untreated. Secondary outcomes included the total amount of iron administered before delivery, the time interval from admission to delivery, and neonatal effects. Results Two hundred sixty-three women were admitted, 79 women had anemia, and 29 (36.7%) received at least one dose of oral iron. Baseline patient characteristics were similar between groups. The median (interquartile range) dose of iron in the oral iron group was 1185.0 (477.0, 1874.0) mg. Neither absolute hemoglobin before delivery (control group: 10.0±1.2 g/dL; iron group: 10.1±1.1 g/dL; p=0.774) nor change in hemoglobin from admission to delivery (control group: -0.1±1.1 g/dL vs. iron group: 0.4±1.1 g/dL; p=0.232) differed between groups. Women in the control group had shorter length of stay (LOS) median (IQR) than women in the iron group (control group: 7.1 (5.0, 13.7) days; iron group: 11.4 (7.4, 25.9) days; p=0.03). There were no differences in maternal mode of delivery, though each group had high rates of cesarean delivery (control group: 53.7%; iron group: 72.4%; p=0.181). There were no differences in estimated blood loss at delivery (control group: 559±401; iron group: 662.1±337.4;p=0.264) in either group. Neonatal birthweight (control group: 1.9±0.7 kg; iron group: 1.9±0.7 kg; p=0.901), birth hemoglobin (control group: 16.3±2.2 g/dL; iron group: 16±2.2 g/dL; p=0.569), neonatal intensive care unit (NICU) admission (control group: 93.3%; iron group: 84.8%;p=0.272 ), or neonatal death (control group: 8.9%; iron group: 3%; p=0.394) were not different between groups. Conclusions Oral iron administered to anemic inpatient pregnant women was not associated with higher hemoglobin concentrations before delivery. Lack of standardized iron regimens and short hospital stays may contribute to the inefficacy of oral iron for this inpatient pregnant population. The small sample size and retrospective nature of this study are limiting factors in drawing conclusive evidence from this study.

Implementation of an Epidural Rounding Reminder in the Electronic Medical Record Improves Performance of Standardized Patient Assessments during Labor

BACKGROUND

Poorly functioning labor epidural catheters lead to pain and dissatisfaction. Regular catheter assessment ensures timely identification of malfunction and may improve safety by facilitating rapid and successful conversion to general anesthesia for emergency cesarean. Informatics-based systems encourage standardization of care to identify epidural malfunctions earlier.

OBJECTIVES

This article demonstrates that visual epidural rounding reminder display on an electronic patient board would alert clinicians to elapsed time and decrease mean time between assessments.

METHODS

As a quality initiative, we implemented an epidural rounding reminder on our obstetric patient board. The reminder indicated the number of elapsed minutes since placement or last patient assessment. We retrospectively reviewed labor epidural charts 3 months prior to and 5 months following reminder implementation, with a 4-week washout period. The primary outcome was mean time between documented epidural assessments, with secondary outcomes including maximum time between assessments, total number of assessments during labor, catheter replacement rates, and patient satisfaction. Unadjusted comparisons between pre- and postimplementation groups were conducted using Wilcoxon's rank-sum and Pearson's chi-square tests, as appropriate. A test for equal variances was conducted for time between assessment outcomes.

RESULTS

Following implementation, mean time between assessments decreased from a median of 173 (interquartile range [IQR]: 53, 314) to 100 (IQR: 74, 125) minutes (p <0.001), and maximum time between assessments decreased from median 330 (IQR: 60, 542) to 162 (IQR: 125, 212) minutes (p < 0.001). Total number of evaluations during labor increased from 3 (IQR: 2, 4) to 5 (IQR: 3, 7; p < 0.001). Decreased variance in mean and maximum time between assessments was noted following reminder implementation (p < 0.001). Epidural replacement rates decreased from 14 to 5% postimplementation (p < 0.001). Patient satisfaction was unchanged.

CONCLUSION

Implementation of an informatics-based solution can promote standardization of care. A simple epidural rounding reminder prompted clinicians to perform more frequent labor epidural assessments. In the future, these process improvements must be linked to improvements in patient experiences and outcomes.

Post-cesarean gabapentin is not associated with lower opioid consumption or pain scores in women on chronic buprenorphine therapy: A 10-year retrospective cohort study

STUDY OBJECTIVE

To determine if postoperative gabapentin administration is associated with decreased opioid consumption or pain scores following cesarean delivery in women on chronic buprenorphine.

DESIGN

Retrospective cohort study.

SETTING

Postoperative recovery area and postpartum inpatient unit.

PATIENTS

214 women undergoing cesarean delivery while on chronic buprenorphine at a single institution between 2007 and 2017.

INTERVENTIONS

Gabapentin treatment for post-cesarean analgesia.

MEASUREMENTS

The primary outcome was opioid consumption in morphine milligram equivalents, comparing patients who received ≥1 dose of gabapentin within 24 h of cesarean delivery to those who did not. Secondary outcomes included opioid consumption 24-48 and 48-72 h post-cesarean and postoperative numerical rating scale pain scores.

MAIN RESULTS

Of 214 included patients, 64 (30%) received gabapentin while 150 (70%) did not. Gabapentin patients were more likely than controls to have received neuraxial fentanyl (30% vs. 14%, p = 0.01) and transversus abdominis plane block (6% vs. 1%, p = 0.05) and overall received higher doses of ketorolac and acetaminophen. Control patients were more likely to have received neuraxial morphine (78% vs. 90%, p = 0.04) and received higher doses of ibuprofen. In unadjusted analysis, there was no significant difference in morphine milligram equivalent consumption 0-24 h postoperatively between gabapentin (55 mg [IQR 26,84]) and control (53 mg [IQR 28,75]) groups (p = 0.38). After controlling for potential confounders, there remained no significant effect of gabapentin administration (overall effect p = 0.99). Opioid consumption and pain scores were also not significantly different at any other time points.

CONCLUSIONS

In parturients receiving chronic buprenorphine, inclusion of gabapentin in a multimodal analgesic regimen was not associated with lower opioid consumption or pain scores during the first 72 h after cesarean delivery. Prospective randomized studies are needed to confirm these findings.

Enhanced Recovery after Surgery: Cesarean Delivery

This review summarizes the importance of enhanced recovery after surgery (ERAS) implementation for cesarean deliveries (CDs) and explores ERAS elements shared with the non-obstetric surgical population. The Society for Obstetric Anesthesia and Perinatology (SOAP) consensus statement on ERAS for CD is used as a template for the discussion. Suggested areas for research to improve our understanding of ERAS in the obstetric population are delineated. Strategies and examples of anesthesia-specific protocol elements are included.

Quantifying the incidence of clinically significant respiratory depression in women with and without obesity class III receiving neuraxial morphine for post-cesarean analgesia: a retrospective cohort study

BACKGROUND

Obesity is a suspected risk factor for respiratory depression following neuraxial morphine for post-cesarean analgesia, however monitoring guidelines for obese obstetric patients are based on small, limited studies. We tested the hypothesis that clinically significant respiratory depression following neuraxial morphine occurs more commonly in women with body mass index (BMI) ≥40 kg/m² compared with BMI <40 kg/m².

METHODS

We conducted a single-center, retrospective chart review (2006-2017) of obstetric patients with clinically significant respiratory depression following neuraxial morphine, defined as: (1) opioid antagonist administration; (2) rapid response team activation (initiated in April 2010); or (3) tracheal intubation due to a respiratory event. The incidence of respiratory depression was compared between women with BMI ≥40 kg/m² and BMI <40 kg/m².

RESULTS

In total, 11 327 women received neuraxial morphine (n=1945 BMI ≥40 kg/m²; n=9382 BMI <40 kg/m²). Women with BMI ≥40 kg/m² had higher rates of sleep apnea, hypertensive disorders, and magnesium administration. Sixteen cases of clinically significant respiratory depression occurred within seven days postpartum. The incidence did not significantly differ between groups (odds ratio 2.2, 95% CI 0.6 to 6.9, P=0.174). Neuraxial morphine was not deemed causative in any case, however women with BMI ≥40 kg/m² had higher rates of tracheal intubation unrelated to neuraxial morphine (2/1945 vs. 0/9382, P=0.029).

CONCLUSIONS

Respiratory depression in this population is rare. A larger sample (∼75 000) is required to determine whether the incidence is higher with BMI ≥40 kg/m². Tracheal intubation was higher among the BMI ≥40 kg/m² cohort, likely due to more comorbidities.

Transcutaneous Carbon Dioxide Measurements in Women Receiving Intrathecal Morphine for Cesarean Delivery: A Prospective Observational Study

BACKGROUND

Neuraxial morphine is the most commonly used analgesic technique after cesarean delivery. The incidence of respiratory depression is reported to be very low (0%-1.2%) in this patient population as measured by pulse oximetry and respiratory rates. However, hypercapnia may be a more sensitive measure of respiratory depression. In the current study, the incidence of hypercapnia events (transcutaneous CO2 [TcCO2] >50 mm Hg) for ≥2-minute duration was evaluated using the Topological Oscillation Search with Kinematical Analysis monitor in women who received intrathecal morphine for postcesarean delivery analgesia.

METHODS

Healthy women (>37 weeks of gestation) scheduled for a cesarean delivery with spinal anesthesia with intrathecal morphine were recruited. Baseline STOP-BANG sleep apnea questionnaire and TcCO2 readings were obtained. Spinal anesthesia was initiated with 12 mg hyperbaric bupivacaine, 15 µg fentanyl, and 150 µg morphine. The Topological Oscillation Search with Kinematical Analysis monitor was reapplied in the postanesthesia care unit and TcCO2 measurements obtained for up to 24 hours. Supplemental opioid administration and adverse respiratory events were recorded. The primary outcome was the incidence of hypercapnia events, defined as a TcCO2 reading >50 mm Hg for ≥2 minutes in the first 24 hours after delivery.

RESULTS

Of the 120 women who were recruited, 108 completed the study. Thirty-five women (32%; 99.15% confidence interval, 21%-45%) reached the primary outcome of a sustained hypercapnia event. The median time (interquartile range [IQR]) from intrathecal morphine administration to the hypercapnia event was 300 (124-691) minutes. The median (IQR) number of events was 3 (1-6) and longest duration of an event was 25.6 (8.4-98.7) minutes. Baseline median (IQR) TcCO2 measurements were 35 (30-0) mm Hg and postoperatively, median (IQR) TcCO2 measurements were 40 (36-43) mm Hg, a difference of 5 mm Hg (99.15% confidence interval of the difference 2-8 mm Hg, P < .001). The incidence of hypercapnia events was 5.4% in women with a baseline TcCO2 value ≤31 mm Hg, 22.5% with a baseline TcCO2 between 32 and 38 mm Hg, and 77.4% with a baseline TcCO2 >38 mm Hg (P < .001).

CONCLUSIONS

Hypercapnia events (>50 mm Hg for ≥2-minute duration) occurred frequently in women receiving 150 μg intrathecal morphine for postcesarean analgesia. Higher baseline TcCO2 readings were observed in women who had hypercapnia events.

Evidence-based anesthesia for major gynecologic surgery

Studies on enhanced recovery after gynecological surgery are limited but seem to report outcome benefits similar to those reported after colorectal surgery. Regional anesthesia is recommended in enhanced recovery protocols. Effective regional anesthetic techniques in gynecologic surgery include spinal anesthesia, epidural analgesia, transversus abdominis plane blocks, local anesthetic wound infusions and intraperitoneal instillation catheters. Non-opioid analgesics including pregabalin, gabapentin, NSAIDs, COX-2 inhibitors, and paracetamol reduce opioid consumption after surgery. This population is at high risk for PONV, thus, a multimodal anti-emetic strategy must be employed, including strategies to reduce the baseline risk of PONV in conjunction with combination antiemetic therapy.

Low-dose ketamine with multimodal postcesarean delivery analgesia: a randomized controlled trial

BACKGROUND

Ketamine at subanesthetic doses has analgesic properties that have been shown to reduce postoperative pain and morphine consumption. We hypothesized that intravenous ketamine 10mg administered during spinal anesthesia for cesarean delivery, in addition to intrathecal morphine and intravenous ketorolac, would decrease the incidence of breakthrough pain and need for supplemental postoperative analgesia.

METHODS

Using a randomized double-blind placebo-controlled design, healthy women scheduled for cesarean delivery receiving hyperbaric spinal bupivacaine, fentanyl and morphine were randomized to intravenous ketamine 10mg or saline following delivery. Postoperative analgesia included scheduled ketorolac and acetaminophen/hydrocodone tablets as needed for breakthrough pain. The primary outcome was the incidence of breakthrough pain in the first 24h. Secondary outcomes included the number of acetaminophen/hydrocodone tablets administered and numeric rating scale for pain (0-10).

RESULTS

Group characteristics did not differ. There was no difference in the incidence of breakthrough pain (ketamine 75% VS. saline 74%, P=0.86). There was no difference in 24-h or 72-h use of supplemental acetaminophen/hydrocodone tablets between groups. Pain scores in the first 24h were similar, but lower in the ketamine compared to the saline group 2weeks postpartum (difference -0.6, 95% CI -1.1 to -0.9).

CONCLUSIONS

We found no additional postoperative analgesic benefit of low-dose ketamine during cesarean delivery in patients who received intrathecal morphine and intravenous ketorolac. Subjects who received ketamine reported lower pain scores 2weeks postpartum.

Focused review: neuraxial morphine and oral herpes reactivation in the obstetric population

Neuraxial morphine administration is a common strategy for providing postcesarean delivery analgesia. Morphine delivered via this route increases the risk of herpes labialis (oral herpes) reactivation, a disease common in women of childbearing age. A primary concern is risk of transmission to the neonate from maternal reactivation. The benefits to the mother of this form of analgesia outweigh the risk of neonatal herpes acquired postpartum from maternal recurrence because serious neonatal morbidity from recurrent herpes has not been described.

Biochemical and functional analysis of a conserved IGF-binding protein isolated from rainbow trout (Oncorhynchus mykiss) hepatoma cells

Rainbow trout (Oncorhynchus mykiss) serum contains several IGF-binding proteins (IGFBPs) that specifically bind to IGFs. The structures of these fish IGFBPs have not been determined and their physiological functions are poorly defined. In this study, we identified a 30 kDa IGFBP present in rainbow trout serum and secreted by cultured trout hepatoma cells. This IGFBP binds to IGFs but not to insulin. This IGFBP was purified to homogeneity using a three-step procedure involving Phenyl-Sepharose chromatography, IGF-I affinity chromatography and reverse-phase HPLC. Affinity cross-linking studies indicated that this IGFBP binds to IGF-I with a higher affinity than to IGF-II. N-terminal sequence analysis of the trout IGFBP suggests that it shares high sequence identity with that of human IGFBP-1 in the N-terminal region. When added to cultured fish and human cells, the trout IGFBP inhibited IGF-I-stimulated DNA synthesis and cell proliferation in a concentration-dependent manner. The inhibitory effect of the fish IGFBP was comparable to those of human IGFBP-1 and -4. These results indicate that the IGFBP molecule is structurally and functionally conserved in evolutionarily ancient vertebrate species such as bony fish.

Phosphatidylinositol 3-kinase is required for insulin-like growth factor-I-induced vascular smooth muscle cell proliferation and migration

Insulin-like growth factor-I (IGF-I) plays an important role in regulating vascular smooth muscle cell (VSMC) proliferation and directed migration. The mitogenic and chemotactic actions of IGF-I are mediated through the IGF-I receptor, but how the activation of the IGF-I receptor leads to these biological responses is poorly understood. In this study, we examined the role of phosphatidylinositol 3-kinase (PI3 kinase) in mediating the mitogenic and chemotactic signals of IGF-I. IGF-I treatment resulted in a significant increase in phosphotyrosine-associated PI3 kinase activity in cultured primary VSMCs. To determine whether insulin receptor substrate (IRS)-1, -2, or both are involved in IGF-I signaling in VSMCs, cell lysates were immunoprecipitated with either an anti-IRS-1 or an anti-IRS-2 antibody, and the associated PI3 kinase activity was determined. IGF-I stimulation resulted in a significant increase in IRS-1- but not IRS-2-associated PI3 kinase activity, suggesting that IGF-I primarily utilizes IRS-1 to transmit its signal in VSMCs. The IGF-I-induced increase in IRS-I-associated PI3 kinase activity was concentration dependent. At the maximum concentration (50 ng/mL), IGF-I induced a 60-fold increase. This activation occurred within 5 minutes and was sustained at high levels for at least 6 hours. IGF-I also caused a concentration-dependent and long-lasting activation of protein kinase B (PKB/Akt). Inhibition of PI3 kinase activation by LY294002 or wortmannin abolished IGF-I-stimulated VSMC proliferation and reduced IGF-I-directed VSMC migration by approximately 60%. These results indicate that activation of PI3 kinase is required for both IGF-I-induced VSMC proliferation and migration.

Down-regulation of protein kinase C inhibits insulin-like growth factor I-induced vascular smooth muscle cell proliferation, migration, and gene expression

Insulin-like growth factor-I (IGF-I) plays an important role in regulating vascular smooth muscle cell (VSMC) proliferation, directed migration, differentiation, and apoptosis. The signaling mechanisms used by IGF-I to elicit these actions, however, are not well defined. In this study, we examined the role(s) of protein kinase C (PKC) in mediating the IGF-I actions in cultured porcine VSMCs. Out of the eleven known members of PKC family, PKC-alpha, -betaI, -epsilon, -eta, -lambda, -theta, and -zeta, were detectable by Western immunoblot analysis in these cells. Further analysis indicated that the subcellular distribution of several PKC isoforms is regulated by IGF-I. While IGF-I stimulated membrane translocation of PKC-eta, -epsilon, and -zeta and regulated the cytosolic levels of PKC-betaI, it had no such effect on PKC-alpha and -lambda. To examine whether PKC activation is required for the IGF-I-regulated biological responses, phorbol myristate acetate (PMA) and GF109203X were used to down-regulate or inhibit PKC activity. Both PMA (1 microM) and GF109203X (20 microM) nearly completely suppressed the total PKC activity after a 30-min incubation (> 90%), and this inhibition lasted for at least 24 h. Down-regulation or inhibition of PKC activity abolished the IGF-I-induced DNA synthesis, migration and IGFBP-5 gene expression. In contrast, the IGFBP-5 expression induced by forskolin was unaffected by PKC down-regulation or inhibition, suggesting that PKC activation is required for the IGF-regulated but not the cAMP-regulated events. Because the actions of IGF-I on DNA synthesis and IGFBP-5 gene expression in VSMCs have been shown to be mediated through the phosphatidylinositol 3-kinase (PI3 kinase) signaling pathway in porcine VSMCs, the potential role of PKC in IGF-I-induced activation of PI3 kinase and PKB/Akt were examined. Treatment with either PMA or GF109203X did not significantly affect the effects of IGF-I on PI3 kinase activation or PKB/Akt phosphorylation. These results indicated that PKC-betaI, -eta, -epsilon, and -zeta may play an essential role(s) in IGF-I regulation of VSMC migration, DNA synthesis and gene expression, and that these PKC isoforms may either act independently of the PI3 kinase pathway or act further downstream of PKB/Akt in the IGF signaling network.