David Baud

Extension of Murray's law using a non-Newtonian model of blood flow

BackgroundSo far, none of the existing methods on Murrays law deal with the non-Newtonian behavior of blood flow although the non-Newtonian approach for blood flow modelling looks more accurate.ModelingIn the present paper, Murrays law which is applicable to an arterial bifurcation, is generalized to a non-Newtonian blood flow model (power-law model). When the vessel size reaches the capillary limitation, blood can be modeled using a non-Newtonian constitutive equation. It is assumed two different constraints in addition to the pumping power: the volume constraint or the surface constraint (related to the internal surface of the vessel). For a seek of generality, the relationships are given for an arbitrary number of daughter vessels. It is shown that for a cost function including the volume constraint, classical Murrays law remains valid (i.e. ΣRc= cste with c = 3 is verified and is independent of n, the dimensionless index in the viscosity equation; R being the radius of the vessel). On the contrary, for a cost function including the surface constraint, different values of c may be calculated depending on the value of n.ResultsWe find that c varies for blood from 2.42 to 3 depending on the constraint and the fluid properties. For the Newtonian model, the surface constraint leads to c = 2.5. The cost function (based on the surface constraint) can be related to entropy generation, by dividing it by the temperature.ConclusionIt is demonstrated that the entropy generated in all the daughter vessels is greater than the entropy generated in the parent vessel. Furthermore, it is shown that the difference of entropy generation between the parent and daughter vessels is smaller for a non-Newtonian fluid than for a Newtonian fluid.

Pelvic floor dysfunction 6 years post-anal sphincter tear at the time of vaginal delivery

Introduction and hypothesisThis study aims to estimate fecal, urinary incontinence, and sexual function 6 years after an obstetrical anal sphincter tear.MethodsAmong 13,213 women who had a vaginal delivery of a cephalic singleton at term, 196 women sustained an anal sphincter tear. They were matched to 588 controls. Validated questionnaires grading fecal and urinary incontinence, and sexual dysfunction were completed by the participants.ResultsSevere fecal incontinence was more frequently reported by women who had sustained an anal sphincter tear compared to the controls. Women with an anal sphincter tear had no increased risk of urinary incontinence, but reported significantly more pain, difficulty with vaginal lubrication, and difficulty achieving orgasm compared to the controls. A fetal occiput posterior position during childbirth was an independent risk factor for both severe urinary incontinence and severe sexual dysfunction.ConclusionsFecal incontinence is strongly associated with an anal sphincter tear. A fetal occiput posterior position represents a risk factor for urinary incontinence and sexual dysfunction.

Birth records from Swiss married couples analyzed over the past 35 years reveal an aging of first-time mothers by 5.1 years while the interpregnancy interval has shortened

Although the general trend for delaying childbearing is generally viewed as causing infertility, its consequences on the interpregnancy interval have been unknown. A study of birth records for Swiss married women from 1969 to 2006 revealed that the womans age at first birth has increased from 25.0 to 30.1 years, whereas calculated theoretical interpregnancy intervals after the first and second child decreased from 23.2 to 13 and from 22.4 to 7.9 months, respectively.

Simkania negevensis, an insight into the biology and clinical importance of a novel member of the Chlamydiales order.

Abstract Simkania negevensis is a Chlamydia-related bacterium discovered in 1993 and represents the founding member of the Simkaniaceae family within the Chlamydiales order. As other Chlamydiales, it is an obligate intracellular bacterium characterized by a biphasic developmental cycle. Its similarities with the pathogenic Chlamydia trachomatis and Chlamydia pneumoniae make it an interesting bacterium. So far, little is known about its biology, but S. negevensis harbors various microbiological characteristics of interest, including a strong association of the Simkania-containing vacuole with the ER and the presence of an intron in the 23S rRNA encoding gene. Evidence of human exposition has been reported worldwide. However, there is a lack of robust clinical studies evaluating its implication in human diseases; current data suggest an association with pneumonia and bronchiolitis making S. negevensis a potential emerging pathogen. Owing to its fastidious growth requirements, the clinical relevance of S. negevensis is probably underestimated. In this review, we summarize the current knowledge on S. negevensis and explore future research challenges.

Fetal laser therapy: applications in the management of fetal pathologies

Fetoscopic coagulation of placental anastomoses is the treatment of choice for severe twin‐to‐twin transfusion syndrome. In the present day, fetal laser therapy is also used to treat amniotic bands, chorioangiomas, sacrococcygeal teratomas, lower urinary tract obstructions and chest masses, all of which will be reviewed in this article. Amniotic band syndrome can cause limb amputation by impairing downstream blood flow. Large chorioangiomas (>4 cm), sacrococcygeal teratomas or fetal hyperechoic lung lesions can lead to fetal compromise and hydrops by vascular steal phenomenon or compression. Renal damage, bladder dysfunction and lastly death because of pulmonary hypolasia may be the result of megacystis caused by a posterior urethral valve. The prognosis of these pathologies can be dismal, and therapy options are limited, which has brought fetal laser therapy to the forefront. Management options discussed here are laser release of amniotic bands, laser coagulation of the placental or fetal tumor feeding vessels and laser therapy by fetal cystoscopy. This review, largely based on case reports, does not intend to provide a level of evidence supporting laser therapy over other treatment options. Centralized evaluation by specialists using strict selection criteria and long‐term follow‐up of these rare cases are now needed to prove the value of endoscopic or ultrasound‐guided laser therapy.

Effect of maternal betamethasone on hydrops fetalis caused by extralobar pulmonary sequestration: a case report

Bronchopulmonary sequestration (BPS) is a rare malformation of the respiratory tract characterised by a mass of non-functional pulmonary tissue, separated from the tracheobronchial tree and supplied by a separate systemic artery (Achiron et al. 2004). Up to 68% of these lesions may regress during prenatal follow-up. Some of these lesions will stop growing. In a minority of cases, BPS may grow rapidly and may be associated with pleural effusion and subsequently develop heart failure and foetal hydrops. In these rare cases, prenatal intervention might be necessary to prevent further deterioration of foetal well-being. Several prenatal treatments have been described, including pleuroamniotic shunting, thoracocentesis, sclerosing therapy, laser coagulation and open foetal surgery (Witlox et al. 2011; Baud et al. 2013). We report the case of a left isolated extralobar pulmonary sequestration complicated with a pleural effusion and a right cardiac shift, treated successfully with a repeated maternal injection of betamethasone.

Utility of an Algorithm to Increase the Accuracy of Medication History in an Obstetrical Setting

Background In an obstetrical setting, inaccurate medication histories at hospital admission may result in failure to identify potentially harmful treatments for patients and/or their fetus(es). Methods This prospective study was conducted to assess average concordance rates between (1) a medication list obtained with a one-page structured medication history algorithm developed for the obstetrical setting and (2) the medication list reported in medical records and obtained by open-ended questions based on standard procedures. Both lists were converted into concordance rate using a best possible medication history approach as the reference (information obtained by patients, prescribers and community pharmacists’ interviews). Results The algorithm-based method obtained a higher average concordance rate than the standard method, with respectively 90.2% [CI95% 85.8–94.3] versus 24.6% [CI95%15.3–34.4] concordance rates (p<0.01). Conclusion Our algorithm-based method strongly enhanced the accuracy of the medication history in our obstetric population, without using substantial resources. Its implementation is an effective first step to the medication reconciliation process, which has been recognized as a very important component of patients’ drug safety.

OC105: Ultrasound prediction of preterm delivery using variable cut-off value of cervical length

Objectives: Recently, we have showed significance of cervical gland area (CGA) to predict preterm delivery. An absent CGA reflects advanced maturation of uterine cervix during gestation. The objective was to explore whether an absent CGA is a predictive finding for preterm delivery < 34 weeks’ gestation (PTD) and to compare predictive efficacy with a short CL (< 20 mm) and positive fFN (> 50 ng/mL) in vaginal secretions that have been widely accepted. Methods: This is a retrospective case-note review for 108 subjects, ranging between 22 ≤ and < 34 wks’ of gestation, who were admitted to our hospital due to threatened preterm delivery during April, 2007 and March, 2008. CL and CGA were observed by TVS and fFN was sampled in vaginal secretions on admission. Relationships between the findings and prevalence of PTD was analyzed. Results: 1) 14.8% ended in PTD. 2) 45.0% had an absent CGA, 42.6% had a short CL and 19.4% had a positive fFN on admission. 14.8% had both TVS findings. 3) Patients suffered from PTD had more findings of a short CL (75%), an absent CGA (68.8%), a short CL without CGA (62.5%) and positive fFN (62.5%) than those delivered ≥ 34 weeks of gestation (P < 0.05). 4) Stepwise logistic regression built a model to predict PTD with significant independent explanatory parameters of positive fFN and a short CL without CGA (P < 0.001). Other possible explanatory parameters including an absent CGA, a short CL, twin pregnancy, cerclage, parity and maternal ages were not taken as a parameter, Odds ratio of positive fFN and a short CL without CGA was 7.67 (95% Confidential intervals;1.97–29.90) and 5.51 (1.43–21.22), respectively. 4) Patients with positive fFN delivered early from the admission when a short CL and an absent CGA already coexisted, compared with those without both findings (Mean interval to delivery was 2.9 vs. 9.3 weeks: P < 0.0005). Conclusion: Combined TVS finding of a short CL with an absent CGA is an independent predictor for PTD.