Depletion of penicillin G residues in heavy sows after intramuscular injection. Part I: tissue residue depletion.

Heavy sows (n = 126) were treated with penicillin G procaine at a 5× label dose (33 000 IU/kg) for 3 consecutive days by intramuscular (IM) injection using three patterns of drug administration. Treatments differed by injection pattern and injection volume. Sets of sows were slaughtered 5, 10, 15, 20, 25, 32, and 39 days after the last treatment; skeletal muscle, kidney, serum, and urine were collected for penicillin G analysis by LC-MS/MS. Penicillin G at withdrawal day 5 averaged 23.5 ± 10.5 and 3762 ± 1932 ng/g in muscle and kidney, respectively. After 15 days of withdrawal, muscle penicillin G residues were quantifiable in only one treated hog (3.4 ng/g) but averaged 119 ± 199 ng/g in kidneys. Using a hypothetical tolerance of 50 ng/g and a natural log-linear depletion model, the withdrawal period required for penicillin depletion to 50 ng/g was 11 days for skeletal muscle and 47 days for kidney.

Measuring perinatal mental health risk.

The purpose of this review was to critically analyse existing tools to measure perinatal mental health risk and report on the psychometric properties of the various approaches using defined criteria. An initial literature search revealed 379 papers, from which 21 papers relating to ten instruments were included in the final review. A further four papers were identified from experts (one excluded) in the field. The psychometric properties of six multidimensional tools and/or criteria were assessed. None of the instruments met all of the requirements of the psychometric properties defined. Some had used large sample sizes but reported low positive predictive values (Antenatal Risk Questionnaire (ANRQ)) or insufficient information regarding their clinical performance (Antenatal Routine Psychosocial Assessment (ARPA)), while others had insufficient sample sizes (Antenatal Psychosocial Health Assessment Tool, Camberwell Assessment of Need-Mothers and Contextual Assessment of Maternity Experience). The ANRQ has fulfilled the requirements of this analysis more comprehensively than any other instrument examined based on the defined rating criteria. While it is desirable to recommend a tool for clinical practice, it is important that clinicians are made aware of their limitations. The ANRQ and ARPA represent multidimensional instruments commonly used within Australia, developed within large samples with either cutoff scores or numbers of risk factors related to service outcomes. Clinicians can use these tools, within the limitations presented here, to determine the need for further intervention or to refer women to mental health services. However, the effectiveness of routine perinatal psychosocial assessment continues to be debated, with further research required.

OS010. Use of retinal imaging to characterise physiological vascularchanges throughout pregnancy.

INTRODUCTION: Visualisation of the microcirculation through retinal imaging can provide information on the health of systemic vasculature. Characterisation of the retinal vasculature throughout pregnancy using retinal imaging is a novel approach to examine physiological changes to the cardiovascular system, and may be useful to predict early pathophysiological signs of adverse maternal outcomes. OBJECTIVES: To characterise the retinal vascular and blood pressure (BP) changes that occur throughout a healthy pregnancy. METHODS: Data was collected from women recruited at 13±2 weeks of gestation from Royal Prince Alfred Hospital, a major tertiary referral hospital in Sydney, Australia. Retinal images centred on the optic disc and BP readings were collected throughout pregnancy. Postnatal data was collected from medical records, and women with hypertensive disorders of pregnancy and gestational diabetes mellitus were excluded. This left a final group of 19 women. Retinal images from 13±2, 19±2, 29±2 and 38±2 weeks gestation were graded using semi-automated retinal vascular calibre measurement (IVAN) software and the central retinal arteriolar equivalent (CRAE), and central retinal venular equivalent (CRVE). BP data was collected at the same time points as the retinal images. Analysis of data was performed using paired t-tests and repeated measures analysis of variance (ANOVA). Women with missing data points were excluded from the analysis at the relevant time points. RESULTS: Over the course of pregnancy, there was a significant dilatation of retinal arterioles between 13±2 and 19±2weeks (from 166.4 to 172.7µm, SE: 3.7µm, n=19, p=0.01), corresponding to a significant fall in diastolic BP during this time (from 64.6 to 60.2mmHg, SE: 1.5mmHg, p=0.01). No significant changes in venular diameter or systolic BP were noted. Between 19±2 and 29±2weeks (n=4), no significant changes to retinal arteriolar or venular diameter were seen although there were significant increases in both systolic and diastolic BP (SBP: from 100.3 to 109.9mmHg, SE: 1.9mmHg, p=0.01; DBP: from 59.3 to 64.6mmHg, SE: 6.9mmHg, p=0.01). Between 29±2 and 38±2weeks (n=3), no significant changes in retinal arteriolar, and venular diameter or BP were observed. CONCLUSION: An increase in retinal arteriolar diameter between 13±2 and 19±2 weeks gestation was observed, which corresponded to a decrease in both systolic and diastolic BP. However, between 19±2 and 29±2 weeks there was no change in vasculature, even though there was a significant increase in BP. By characterising the changes to retinal vessels that occur throughout a healthy pregnancy, we can further our understanding of the response of the systemic vasculature to pregnancy, which may provide clues to early vascular disease of pregnancies.

OS016. Retinal vascular changes in hypertensive disorders of pregnancy.

INTRODUCTION: Hypertensive disorders of pregnancy (HDP) are characterised by vascular dysfunction. Retinal vascular imaging is a novel, non-invasive way to characterise early microvascular changes in pregnancy, and as a result has the potential to be used to predict the onset of HDP. OBJECTIVES: To characterise retinal vascular changes that occur in HDP, and compare these changes to those in healthy pregnancies. METHODS: Women were recruited at 13±2 weeks of gestation from Royal Prince Alfred Hospital, a major metropolitan tertiary referral hospital in Sydney, Australia. Retinal images centred on the optic disc and blood pressure (BP) readings were collected at 13±2, 19±2, 29±2 and 38±2 weeks gestation. Retinal images were graded using semi-automated retinal vascular calibre measurement software (IVAN) and the central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were calculated. Within and between subject repeat measures analysis was performed on images from each trimester, using paired t-tests and repeated measures analysis of variance (ANOVA). Multiple linear regressions were used to model the average arteriole diameter adjusted for age, tobacco consumption and body mass index (BMI). All tests were two-sided using a 5% level of significance. A clinical diagnosis of HDP was obtained from postnatal medical record data. Women with missing data points were excluded from the analysis at that time point. RESULTS: Of the 39 women included in the study, 6 (15%) were diagnosed with HDP. In the HDP cohort, repeated measures ANOVA revealed no significant changes in arteriolar or venular diameter measurements throughout pregnancy. Paired t-tests indicated no significant differences in any of the outcome measures between HDP and healthy pregnancies at 13±2 (n=36) and 19±2 (n=39)weeks. At 29±2weeks (n=39), there was a significantly smaller venular diameter in HDP pregnancies (220.4±6.9µm vs 239.1± 5.4µm in healthy pregnancies, p=0.03). At 38±2weeks (n=39), arteriolar diameter was significantly smaller in HDP pregnancies (148.6±6.0µm vs 164.1±4.6µm in healthy pregnancies, p=0.04). Similar results persisted following adjustments for cardiovascular risk factors (age, tobacco use and BMI). CONCLUSION: Significant differences in the retinal vasculature develop in HDP as compared to healthy pregnancies. These differences appear at29±2weeks gestation and persist throughout the rest of the pregnancy. Retinal vascular imaging is a promising tool for the detection of the early microvascular changes in HDP, prior to diagnosis.