Influence of reverse Trendelenburg position on aortocaval compression in obese pregnant women

INTRODUCTION

Obese pregnant women are at risk of aortocaval compression and associated hypotension with neuraxial anaesthesia. We hypothesised that addition of reverse Trendelenburg tilt to the standard practice of pelvic tilt may attenuate aortocaval compression.

METHODS

After ethical approval and consent, six women with a singleton pregnancy and booking body mass index of 30-35kg/m(2) underwent magnetic resonance imaging scanning in six different positions: right lateral decubitus; left lateral decubitus; supine with pelvic tilt; and reverse Trendelenburg positions of 5°, 10° and 15°. Dimensions of the inferior vena cava and abdominal aorta at the L2-3 intervertebral disc level were obtained from axial images using medical imaging software OsiriX™.

RESULTS

Inferior vena cava dimensions were higher in left lateral decubitus position compared to supine with pelvic tilt (P=0.002). Inferior vena cava compression was noted in all participants (59±33%, 95% CI 32 to 86). Addition of 15° reverse Trendelenburg tilt to standard pelvic tilt produced a non-statistically significant increase in inferior vena cava area (10.54±9.91cm(2), 95% CI 2.61 to 18.47, P=0.06).

CONCLUSION

A non-statistically significant improvement of aortocaval compression was noted with the addition of 15° reverse Trendelenburg tilt to the supine with pelvic tilt position in obese pregnant women.

Electrophysiologic Study of a Method of Euthanasia Using Intrathecal Lidocaine Hydrochloride Administered during Intravenous Anesthesia in Horses

Background

An intravenous (IV) overdose of pentobarbital sodium is the most commonly used method of euthanasia in veterinary medicine. However, this compound is not available in many countries or rural areas resulting in usage of alternative methods such as intrathecal lidocaine administration after IV anesthesia. Its safety and efficacy as a method of euthanasia have not been investigated in the horse.

Hypothesis/Objectives

To investigate changes in mean arterial blood pressure and electrical activity of the cerebral cortex, brainstem, and heart during intrathecal administration of lidocaine. Our hypothesis was that intrathecal lidocaine affects the cerebral cortex and brainstem before affecting cardiovascular function.

Animals

Eleven horses requiring euthanasia for medical reasons.

Methods

Prospective observational study. Horses were anesthetized with xylazine, midazolam, and ketamine; and instrumented for recording of electroencephalogram (EEG), electrooculogram (EOG), brainstem auditory evoked response (BAER), and electrocardiogram (ECG). Physical and neurological (brainstem reflexes) variables were monitored. Mean arterial blood pressure was recorded throughout the study.

Results

Loss of cerebro‐cortical electrical activity occurred up to 226 seconds after the end of the infusion of lidocaine solution. Cessation of brainstem function as evidenced by a lack of brainstem reflexes and disappearance of BAER occurred subsequently. Undetectable heart sounds, nonpalpable arterial pulse, and extremely low mean arterial blood pressure supported cardiac death; a recordable ECG was the last variable to disappear after the infusion (300–1,279 seconds).

Conclusions and Clinical Importance

Intrathecal administration of lidocaine is an effective alternative method of euthanasia in anesthetized horses, during which brain death occurs before cardiac death.

Adolescent experiences of anti-obesity drugs

Only two anti-obesity drugs (AODs) are frequently prescribed in paediatric obesity, orlistat and metformin. Meta-analyses show modest benefit in clinical trials, yet analyses of prescribing databases show high levels of discontinuation in routine clinical practice. Increased understanding of young people's experiences taking AOD could result in improved prescribing and outcomes. Semi-structured interviews were conducted with young people aged 13-18 years and their parents from three specialist obesity clinics, analysed using a general thematic coding methodology. Theme saturation was achieved after interviews with 15 young people and 14 parents (13 parent-child dyads). Three models were developed. Model 1 explored factors influencing commencement of AOD. Six themes emerged: medication as a way out of obesity, enthusiasm and relief at the prospect of pharmaceutical treatment, last ditch attempt for some but not all, passive acceptance of medication, fear as a motivating factor, and unique treatments needed for unique individuals. Model 2 described the inter-relationship between dosing and side effects; side effects were a significant experience for many young people, and few adhered to prescribed regimens, independently changing lifestyle and dosage to tolerate medications. Model 3 described the patient-led decision process regarding drug continuation, influenced primarily by side effects and efficacy. Use of AODs is challenging for many adolescents. Multiple factors were identified that could be targeted to improve concordance and maximize efficacy.

Nonmedically indicated induction vs expectant treatment in term nulliparous women

OBJECTIVE

The purpose of this study was to compare maternal and neonatal outcomes in nulliparous women with nonmedically indicated inductions at term vs those expectantly treated.

STUDY DESIGN

Data were obtained from maternal and neonatal charts for all deliveries on randomly selected days across 25 US hospitals over a 3-year period. A low-risk subset of nulliparous women with vertex nonanomalous singleton gestations who delivered 38 0/7 to 41 6/7 weeks were selected. Maternal and neonatal outcomes for nonmedically indicated induction within each week were compared with women who did not undergo nonmedically indicated induction during that week. Multivariable analysis was used to adjust for hospital, maternal age, race/ethnicity, body mass index, cigarette use, and insurance status.

RESULTS

We found 31,169 women who met our criteria. Neonatal complications were either less frequent with nonmedically indicated induction or no different between groups. Nonmedically indicated induction was associated with less frequent peripartum infections (odds ratio [OR], 0.39; 95% confidence interval [CI], 0.16-0.98) at 38 weeks of gestation and less frequent third- and fourth-degree lacerations (OR, 0.60; 95% CI, 0.42-0.86) and less frequent peripartum infections (OR, 0.66; 95% CI, 0.49-0.90) at 39 weeks of gestation. Nonmedically indicated induction was associated with a longer admission-to-delivery time by approximately 3-4 hours and increased odds of cesarean delivery at 38 (OR, 1.50; 95% CI, 1.08-2.08) and 40 weeks (OR, 1.30; 95% CI, 1.15-1.46) of gestation.

CONCLUSION

At 39 weeks of gestation, nonmedically indicated induction is associated with lower maternal and neonatal morbidity than women who are expectantly treated.

Passive immunity stimulated by vaccination of dry cows with a Salmonella bacterial extract

Background

Diarrhea because of Salmonella infection is a cause of neonatal calf diarrhea. The stimulation of passive immunity in the calf by vaccinating the dam for Salmonella has shown some success in previous studies; however, there are no data on the use of currently licensed vaccines in the United States.

Objective

To determine whether vaccinating cows at dry‐off with a commercially available Salmonella bacterial extract would stimulate Salmonella‐specific antibodies in the colostrum of cows at calving and whether these antibodies would be transferred to the calf.

Animals

Sixty Holstein cattle and 59 calves from a herd presumed to be naïve to Salmonella.

Methods

Prospective clinical trial. Thirty cows were vaccinated at dry‐off with a Salmonella enterica serovar Newport bacterial extract and again 4 weeks later. An additional 30 cows received only saline. Calves fed fresh colostrum from their dam within 4 hours of birth had blood collected 24 hours later.

Results

Vaccinated cattle had increased Salmonella Newport antibody titers at calving in blood (P = .01) and colostrum (P = .011). Calves that received colostrum from vaccinated cattle also had significant increase in Salmonella antibodies (1.04 ± 0.03) as compared to calves born to unvaccinated cows (0.30 ± 0.02).

Conclusions and Clinical Importance

The results indicate that the use of a commercially available Salmonella vaccine can stimulate antibodies that are passed on to the calf via colostral transfer. Further studies need to be done to determine whether these antibodies will offer protection against Salmonella challenge.

Indirect hydrogen analysis by gas chromatography coupled to mass spectrometry (GC-MS)

Gas chromatography (GC) is an analytical tool very useful to investigate the composition of gaseous mixtures. The different gases are separated by specific columns but, if hydrogen (H2 ) is present in the sample, its detection can be performed by a thermal conductivity detector or a helium ionization detector. Indeed, coupled to GC, no other detector can perform this detection except the expensive atomic emission detector. Based on the detection and analysis of H2 isotopes by low-pressure chemical ionization mass spectrometry (MS), a new method for H2 detection by GC coupled to MS with an electron ionization ion source and a quadrupole analyser is presented. The presence of H2 in a gaseous mixture could easily be put in evidence by the monitoring of the molecular ion of the protonated carrier gas.

Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography-mass spectrometry and stable labeled isotope as internal standard

A novel approach to measure carbon dioxide (CO2) in gaseous samples, based on a precise and accurate quantification by (13)CO2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable in the routine determination of CO2. The main drawback of the GC methods discussed in the literature for CO2 measurement is the lack of a specific internal standard necessary to perform quantification. CO2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ((13)CO2) on the basis of the stoichiometric formation of CO2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH(13)CO3). This method allows a precise measurement of CO2 concentration and was validated on various human postmortem gas samples in order to study its efficiency.

Virus vectors for gene delivery to the nervous system

A number of virus vectors have been developed for gene delivery to the nervous system. Virus vectors still provide the most efficient means of gene delivery, and this is critical as only a small volume of inoculum can be used without damaging neurons. Each of the four types of vectors currently in use have their advantages and disadvantages. Highest titers can be achieved with herpes virus and adenovirus vectors, with retrovirus and adeno-associated virus (AAV) vectors currently yielding lower titers. The transgene capacity of each from highest to lowest is: herpes virus (30 kb), adenovirus (8-10 kb), retrovirus (7-8 kb) and AAV (4.5 kb). All can infect a broad range of cell types in the nervous system, including neurons, glia and endothelial cells. Herpes, adenovirus and AAV vectors can deliver genes to postmitotic, as well as mitotic cells, while retrovirus vectors depend on cell mitosis for gene delivery. Herpes virus can assume a stable extrachromosomal configuration in the nuclei of some neurons (termed latency), while both retrovirus and AAV can integrate into the cell genome. Both integrate at random sites, but AAV can also integrate at a specific chromosomal location. Adenovirus neither assumes a stable state nor integrates, still its genome can persist and be expressed in the host cell for some time (up to a month or so). Stability of gene expression is a problem for all the vectors, due in part to the use of viral promoters which tend to be down-regulated by the host cell over a month or so. Both herpes virus vectors and adenovirus vectors have some toxicity in their current configurations, while retrovirus and AAV tend to be associated with less neuropathogenicity. Many developments in vectors should be occurring over the next few years that should increase the potential of these vectors for therapeutic gene delivery.

Polychlorinated naphthalenes (PCNs) in Irish foods: Occurrence and human dietary exposure

The concentrations of selected polychlorinated naphthalene (PCN) congeners (PCNs 52, 53, 66/67, 68, 69, 71/72, 73, 74 and 75) were determined in 100 commonly consumed foods, in the first study on occurrence of these contaminants in the Republic of Ireland. Congener selection was based on current knowledge on PCN occurrence and toxicology, and the availability of reliable reference standards. The determinations were carried out using validated analytical methodology based on 13C10 labelled internal standardisation and measurement by HRGC-HRMS. The results showed PCN occurrence in the majority of studied foods--milk, fish, dairy and meat products, eggs, animal fat, shellfish, offal, vegetables, cereal products, etc. ranging from 0.09 ng kg(-1) whole weight for milk to 59.3 ng kg(-1) whole weight for fish, for the sum of the measured PCNs. The most frequently detected congeners were PCNs 66/67, PCN 52, and PCN 73. The highest concentrations were observed in fish, which generally showed congener profiles that reflect some commercial mixtures. The data compares well with other recently reported data for Western Europe. The dioxin-like toxicity (PCN TEQ) associated with these concentrations is lower than that reported for chlorinated dioxins or PCBs in food from Ireland. The dietary exposure of the Irish adult population to PCNs was calculated following a probabilistic approach, using the full dataset of occurrence and current consumption data. The estimates of dietary intakes at approximately 0.14 pg TEQ kg bw(-1) month(-1) for adults on an average diet, reflects the relatively lower occurrence levels.