Antenatal risk factors in emergency caesarean sections done for fetal distress

Background: Fetal distress is an important indication for emergency caesarean deliveries. The objective of this study is to identify the antenatal and intrapartum risk factors in emergency caesareans done for non-reassuring fetal status and compare with patients who underwent emergency caesareans for other indications.Methods: It was a retrospective study and data was collected from the labour room records of a tertiary care hospital. Patients undergoing emergency caesareans for fetal distress were the cases and the remaining emergency caesareans were the controls. Data was statistically analyzed.Results: There were 5184 deliveries during this period of which, 669 were emergency caesareans. 126 (18.83%) of these were due to fetal distress/ non-reassuring fetal status and 543 (81.17%) were for other indications. Caesarean due to fetal distress accounted for 2.43% of the total deliveries. There were more primigravidae (61.11% Vs 46.04%) in the fetal distress group (Odds Ratio 1.84, p=0.003). Intra uterine growth restriction (OR 5.44, p<0.0001) and antepartum haemorrhage mainly due to abruption (OR 11.19, p <0.0001) were other important antenatal risk factors. Those with neonates of birth weight between 1.5 to 2.0 kgs were more likely to undergo emergency caesarean for fetal distress (OR 1.78, p=0.0435). The risk of a lower APGAR was higher in the fetal distress group (12.59%). 28.34% neonates in this group required NICU admission.Conclusions: Primiparity, intrauterine growth restriction, antepartum hemorrhage and prematurity, have shown to significantly increase the risk of emergency cesareans due to non-reassuring fetal status. We need to improve antenatal care with a goal of early detection of the above risk factors for timely institution of appropriate intervention and thus contributing to a reduction of emergency caesareans due to fetal distress

How to compare arc-annotated sequences: The alignment hierarchy

International audienceWe describe a new unifying framework to express comparison of arc-annotated sequences, which we call alignment of arc-annotated sequences. We first prove that this framework encompasses main existing models, which allows us to deduce complexity results for several cases from the literature. We also show that this framework gives rise to new relevant problems that have not been studied yet. We provide a thorough analysis of these novel cases by proposing two polynomial time algorithms and an NP-completeness proof. This leads to an almost exhaustive study of alignment of arc-annotated sequences

Optical fibre refractive index, voltage and strain sensors : fabrication and applications

The focus of this thesis is the study of intensity and wavelength-based optical fibre sensors (OFSs) for various applications in three major sensing areas: refractive index (RI), voltage and strain. The thesis aims to provide detailed information on the design and performance of particular intensity-based and wavelength-based (fibre Bragg gratings (FBGs)) OFSs in these three major areas. Furthermore, the thesis provides details of multiplexing strategies for some of these sensors

State of charge of battery indicator based on fibre optic probe

A low-cost, high-accuracy fibre optic sensor probe to determine state of charge (SOC) of battery is de monstrated. Capability of extension to multipoint measurements of SOC of stock batteries is also discussed

Multiplexing of fibre optic reflective sensors using Bragg gratings

A multiplexing method for a fibre optic refractive index sensor is presented that is potentially capable of simultaneous measurement from many sensor heads, each of which is a cleaved fibre end. Associated with each sensor head are two fibre couplers and an optical fibre Bragg grating having a unique Bragg wavelength. Experimental characterization of the sensor network through the use of liquids with different refractive indices showed excellent agreement with numerical analysis and a precision of 0.002 RIU and resolution of the order of 10−3 RIU

Electrical energy harvesting device for current/voltage fibre-based sensors

In the context of current/voltage sensing by electric field monitoring it can be of importance to amplify the effect of the field at the sensor’s head. We present such an amplification – or energy harvesting – device in the form of a simple antenna coupled with a liquid crystal-based sensor for the monitoring of high-power lines

Fabrication of a fibre Bragg grating liquid composition sensor based on wet etching technique

An alternative fabrication process targeting the etching of fibre Bragg gratings (FBGs) is presented. The performance of the resulting grating is demonstrated by developing a glycerine composition sensor based on refractive index changes

Response of some pi-phase-shifted Bragg gratings to elevated pressure

The effect of pressures up to 200 kPa on pi-phase-shifted Bragg gratings was investigated in several types of fibers placed in a pressure chamber. Standard and alternative types of pi-phase shifted gratings were studied, and changes in reflection spectra caused by pressure changes were monitored. The alternative pi-phase shifted grating was fabricated using a phase mask with 536-nm pitch exhibiting features at twice the Bragg wavelength near 1552 nm due to the interleaved refractive index modulations along the fiber core with the periodicity of the phase mask. The three gratings studied exhibited quite different variation in Bragg wavelength with increased pressure for the different fiber types, and the alternative pi-phase-shifted grating in Corning HI 1060 FLEX fiber also suffered a significant change in the shape of the peaks