Comparative efficacy of epidural clonidine versus epidural fentanyl for treating breakthrough pain during labor: a randomized double-blind clinical trial

BACKGROUND

Breakthrough pain during neuraxial labor analgesia is typically alleviated with additional administration of epidural local anesthetics, with or without adjuvants. Sometimes avoiding neuraxial opioids may be warranted and clonidine is an alternative. In a randomized double-blind trial we compared the efficacy of clonidine versus fentanyl, added to bupivacaine, for the management of breakthrough pain.

METHODS

Term parturients (n=98) receiving bupivacaine 0.0625% with fentanyl 2 μg/mL at 12 mL/h, a patient-administered bolus of 5 mL at lockout 6-10 min and a maximum of four boluses per hour, and experiencing breakthrough pain ≥5/10, were randomized to receive a 10 mL bolus containing 12.5 mg bupivacaine and either clonidine 100 μg or fentanyl 100 μg. The primary outcome was 'success' of study drug treatment, defined as a pain score reduction ≥4/10 within 15 min of administration. Maternal hemodynamics and fetal heart rate were documented for two hours after treatment.

RESULTS

There was no significant difference between groups in success rates (66.0% after clonidine (n=47) vs 74.5% after fentanyl (n=51), P=0.48) or in the incidence of hypotension (systolic blood pressure ≤80% of baseline or <90 mmHg) or sedation at 15 min, with 2/51 and 1/47 subjects in the fentanyl and clonidine groups, respectively, receiving phenylephrine.

CONCLUSION

Epidural clonidine 100 μg was not superior to fentanyl 100 μg for decreasing pain scores within 15 min of co-administration with bupivacaine 0.125% for intrapartum breakthrough pain. The analgesic efficacy and hemodynamic side effects did not significantly differ.

Reactive oxygen species overproduction and MAP kinase phosphatase-1 degradation are associated with gastroparesis in a streptozotocin-induced male diabetic rat model

BACKGROUND

Diabetic gastroparesis in human and animal models suggest different developmental causes in females vs males. Previously, we demonstrated that although male and female diabetic gastroparetic rats exhibited similarity in disease pathology, molecular mechanisms were different: slow gastric emptying in male diabetic gastroparetic rats was not associated with the level of expression and dimerization of neuronal nitric oxide synthase α in gastric tissues, as was demonstrated in females. Male gastroparesis may involve other mechanisms, such as oxidative stress. We hypothesize that sustained increased reactive oxygen species (ROS) and degradation of MAP kinase phosphatase-1 with subsequent unregulated activation of c-Jun N-terminal kinase and p38MAP kinase pathways are associated with gastroparesis in a male diabetic rat model.

METHODS

Using a male rat model of diabetic gastroparesis, we analyzed serum and pyloric tissue for ROS and antioxidant enzyme levels using ELISA; MAP kinase phosphatase-1, c-Jun N-terminal kinases, and p38MAP kinase levels utilized western blotting techniques and phospho-specific antibodies.

KEY RESULTS

Both diabetic and diabetic gastroparetic rats demonstrated overproduction of ROS. However, loss of MAP kinase phosphatase-1, a MAP kinase pathway negative regulator, with subsequent activation of c-Jun N-terminal kinase 2 and p38MAP kinase pathways, were observed only in diabetic gastroparetic rats. Diabetic rats without gastroparesis had no significant pathway activation.

CONCLUSIONS & INFERENCES

These results suggest that sustained, increased ROS and degradation of MAP kinase phosphatase-1, with subsequent unregulated activation of c-Jun N-terminal kinase and p38MAP kinase pathways, are likely to be factors in diabetic gastroparesis phenotype in a male diabetic rat model.

A study of factors influencing surgical cesarean delivery times in an academic tertiary center

BACKGROUND

Knowledge of hospital-specific average cesarean delivery operative times, and factors influencing length of surgery, can serve as a guide for anesthesiologists when choosing the optimal anesthetic technique. The aim of this study was to determine operative times and the factors influencing those times for cesarean delivery.

METHODS

We conducted a retrospective review of all 1348 cesarean deliveries performed at an academic hospital in 2011. The primary outcome was mean operative time for first, second, third and fourth or more cesarean deliveries. The secondary goal was to identify factors influencing operative time. Variables included age, body mass index, previous surgery, gestational age, urgency of cesarean delivery, anesthesia type, surgeon's seniority, layers closed, and performance of tubal ligation.

RESULTS

Mean (standard deviation) operative times for first (n=857), second (n=353), third (n=108) and fourth or more (n=30) cesarean deliveries were 56 (19), 60 (19), 69 (28) and 82 (31) minutes, respectively (P <0.0001, all groups different). Emergency status of the case and later gestational age were associated with shorter operative times. Higher body mass index, a less senior surgeon, the number of layers closed, and tubal ligation, increased operative times. These factors accounted for 18% of the variability.

CONCLUSIONS

Third and fourth cesarean delivery or the presence of other factors that could increase operative time may warrant catheter-based anesthetic techniques or the addition of adjunctive medications to prolong spinal anesthetic block. Institutional and individual surgeon factors may play an even more important role in determining surgical time.

The association of beta-2 adrenoceptor genotype with short-cervix mediated preterm birth: a case-control study

OBJECTIVE

To determine whether β2 -adrenoceptor (β2 AR) genotype is associated with shortening of the cervix or with preterm birth (PTB) risk among women with a short cervix in the second trimester.

DESIGN

A case-control ancillary study to a multicentre randomised controlled trial.

SETTING

Fourteen participating centres of the Maternal-Fetal Medicine Units Network of the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

POPULATION

Four hundred thirty-nine women, including 315 with short cervix and 124 with normal cervical length.

METHODS

Nulliparous women with cervical length <30 mm upon a 16-22-week transvaginal sonogram and controls frequency-matched for race/ethnicity with cervical lengths ≥40 mm were studied. β2 AR genotype was determined at positions encoding for amino acid residues 16 and 27.

MAIN OUTCOME MEASURES

Genotype distributions were compared between case and control groups. Within the short cervix group, pregnancy outcomes were compared by genotype, with a primary outcome of PTB <37 weeks.

RESULTS

Genotype data were available at position 16 for 433 women and at position 27 for 437. Using a recessive model testing for association between short cervix and genotype, and adjusted for ethnicity, there was no statistical difference between cases and controls for Arg16 homozygosity (OR 0.7, 95% CI 0.4-1.3) or Gln27 homozygosity (OR 0.9, 95% CI 0.3-2.7). Among cases, Arg16 homozygosity was not associated with protection from PTB or spontaneous PTB. Gln27 homozygosity was not associated with PTB risk, although sample size was limited.

CONCLUSIONS

β2 AR genotype does not seem to be associated with short cervical length or with PTB following the second-trimester identification of a short cervix. Influences on PTB associated with β2 AR genotype do not appear to involve a short cervix pathway.

IgE-mediated food allergy--diagnosis and management in New Zealand children

AIM

To summarise the diagnosis and management of IgE-mediated food allergy (FA) in New Zealand children.

METHOD

A review of the scientific literature and subsequent consensus development.

RESULTS

FA is a common problem in New Zealand children with management necessitating accurate diagnosis, appropriate risk management, and reassessment over time.

CONCLUSION

This paper highlights the importance of a structured approach to diagnosis and management of FA in New Zealand children, guided by appropriately skilled health professionals.

Smoke-induced inhalation injury: effects of retinoic acid and antisense oligodeoxynucleotide on stability and differentiated state of the mucociliary epithelium

Rabbit tracheal explants, exposed to burning pine wood smoke, were cultured in a chemically defined medium with and without retinoic acid (+/- RA). Exposures of 15-20 minute led to RA-independent degeneration of the mucociliary epithelial sheath. In 10 minute exposures tissue integrity was retained, but epithelial morphology changed from normal pseudostratified columnar to the flattened appearance typical of the squamous phenotype. Despite the dramatic shift in morphology, explants exhibited normal RA-dependent mucin gene expression characteristic of the mucociliary phenotype. Furthermore, electron micrographs showed continued presence of both secretory granules and cilia. RA(+) cultures also showed a normal pattern of adherent epithelial cells. In RA(-) cultures, however, there were prominent intercellular spaces indicating an RA dependence for maintaining adhesive contacts following smoke exposure. An 18-mer mucin antisense oligomer that suppressed mucin gene expression also unexpectedly blocked the smoke induced metaplasia in RA(+) cultures, but the sense oligomer had no effect.

Modification of normal human myelopoiesis by 12-0 tetradecanoylphorbol-13-acetate (TPA)

The tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), induces macrophage characteristics in the HL-60 promyelocytic leukemia cell line. These same cells can be induced to develop mature myeloid characteristics with a variety of other stimuli. Since normal colony-forming units-culture (CFU C) also have the dual capability of developing colonies with myeloid or monocyte characteristics, the effect of TPA on normal human CFU-C development was studied. To carry out these studies, a method was developed to identify cells histochemically within agar cultures as containing either the myeloid marker, chloroacetate esterase (CAE), or the monocyte marker, nonspecific esterase (NSE). Cells from normal donors were placed into agar cultures with placenta conditioned medium (PCM), TPA in various concentrations, or combinations of PCM and TPA as stimulating materials, and examined after 7-14 days of incubation. TPA alone at concentrations of 5 x 10(-7) M to 10(-9) M stimulated cluster formation. With increasing concentrations of TPA, the percentage of clusters positive for NSE progressively increased, while CAE-positive clusters decreased. I contrast, when TPA at concentrations greater than 10(-9) M was added to PCM, the total number of clusters and colonies decreased. This resulted from a decrease in the number of clusters and colonies that contained the myeloid marker CAE, whereas the number positive for the monocyte marker NSE remained unchanged. These studies demonstrate two effects of TPA on normal CFU-C. In the absence of other sources of colony stimulating activity (CSA), TPA induces clusters. In the presence of PCM, it inhibits the production of myeloid colonies and clusters. Under both conditions, it favors the development of colonies and/or clusters containing predominantly monocytes.