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De Silva D.A.,University of British Columbia | Halstead A.C.,University of British Columbia | Cote A.-M.,Universite de Sherbrooke | Sabr Y.,University of British Columbia | And 3 more authors.
Pregnancy Hypertension | Year: 2013

We evaluated the frequency of measurable albuminuria (≥6.00 mg/L) for albumin:creatinine ratios (ACr) among 160 consecutive women attending high-risk clinics. Of last urine samples before delivery, 76 had measurable albuminuria and 41/76 (53.9%) had ACr ≥2 mg/mmol of which 7.3% had normal pregnancy outcome. 84 samples had albuminuria <6.00 mg/L and 43/84 (51.2%) had ACr ≥2 mg/mmol of which 25.6% had normal pregnancy outcome (p = 0.025). Excluding 48/160 (30.0%) dilute samples (urinary creatinine <3 mM), no samples with unmeasurable albuminuria had ACr ≥2 mg/mmol. In pregnancy, urine is often dilute and without measurable albuminuria, leading to a clinically relevant proportion of false positive results by ACr. © 2013 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved. Source


Ashab H.A.-D.,University of British Columbia | Lessoway V.A.,British Columbia Womens Hospital and Health Center | Khallaghi S.,University of British Columbia | Cheng A.,Johns Hopkins | And 2 more authors.
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS | Year: 2012

Purpose: Spinal needle injection procedures are used for anesthesia and analgesia, such as lumbar epidurals. These procedures require careful placement of a needle, both to ensure effective therapy delivery and to avoid damaging sensitive tissue such as the spinal cord. An important step in such procedures is the accurate identification of the vertebral levels, which is currently performed using manual palpation with a reported 30% success rate for correct identification. Methods: An augmented reality system was developed to help identify the lumbar vertebral levels. The system consists of an ultrasound transducer tracked in real time by a trinocular camera system, an automatic ultrasound panorama generation module that provides an extended view of the lumbar vertebrae, an image processing technique that automatically identifies the vertebral levels in the panorama image, and a graphical interface that overlays the identified levels on a live camera view of the patient's back. Results: Validation was performed on ultrasound data obtained from 10 subjects with different spine arching. The average success rate for segmentation of the vertebrae was 85%. The automatic level identification had an average accuracy of 6.6 mm. Conclusion: The prototype system demonstrates better accuracy for identifying the vertebrae than traditional manual methods. © 2012 IEEE. Source


Norman W.V.,Womens Health Research Institute | Norman W.V.,University of British Columbia | Kaczorowski J.,Womens Health Research Institute | Kaczorowski J.,University of British Columbia | And 11 more authors.
Trials | Year: 2011

Background: We describe the rationale and protocol for a randomized controlled trial (RCT) to assess whether intrauterine contraception placed immediately after a second trimester abortion will result in fewer pregnancies than current recommended practice of intended placement at 4 weeks post-abortion. Decision analysis suggests the novel strategy could substantially reduce subsequent unintended pregnancies and abortions. This paper highlights considerations of design, implementation and evaluation of a trial expected to provide rigorous evidence for appropriate insertion timing and health economics of intrauterine contraception after second trimester abortion.Methods/Design: Consenting women choosing to use intrauterine contraception after abortion for a pregnancy of 12 to 24 weeks will be randomized to insertion timing groups either immediately (experimental intervention) or four weeks (recommended care) post abortion. Primary outcome measure is pregnancy rate at one year. Secondary outcomes include: cumulative pregnancy rates over five year follow-up period, comprehensive health economic analyses comparing immediate and delayed insertion groups, and device retention rates, complication rates (infection, expulsion) and, contraceptive method satisfaction. Web-based Contraception Satisfaction Questionnaires, clinical records and British Columbia linked health databases will be used to assess primary and secondary outcomes. Enrolment at all clinics in the province performing second trimester abortions began in May 2010 and is expected to complete in late 2011. Data on one year outcomes will be available for analysis in 2014.Discussion: The RCT design combined with access to clinical records at all provincial abortion clinics, and to information in provincial single-payer linked administrative health databases, birth registry and hospital records, offers a unique opportunity to evaluate such an approach by determining pregnancy rate at one through five years among enrolled women. We highlight considerations of design, implementation and evaluation of a trial expected to provide rigorous evidence for appropriate insertion timing and health economics of intrauterine contraception after second trimester abortion.Trial registration: Current Controlled Trials ISRCTN19506752. © 2011 Norman et al; licensee BioMed Central Ltd. Source


De Silva D.A.,University of British Columbia | Halstead A.C.,University of British Columbia | Cote A.-M.,Universite de Sherbrooke | Sabr Y.,University of British Columbia | And 3 more authors.
Journal of Obstetrics and Gynaecology Canada | Year: 2014

Objective: To compare the diagnostic test properties of automated and visually read urine dipstick screening for detection of a random protein:creatinine ratio (PrCr) ≥ 30 mg/mmol Methods: Urine samples were collected prospectively from 160 women attending high-risk maternity clinics at a tertiary care facility. Samples were divided into two aliquots; one aliquot was tested using two different urine test strips, one read visually and one by an automated reader. A second aliquot of the same urine was analyzed for urinary protein and creatinine. Performance of visual and automated dipstick results (proteinuria ≥ 1 +) were compared for detection of PrCr. ≥ 30 mg/mmol using non-dilute urine samples (urinary creatinine ≥ 3 mmol/L). Results: Both urine test strips showed low sensitivity (visual 56.0% and automated 53.8%). Positive likelihood ratios were 15.0 for visual dipstick testing (95% CI 5.9 to 37.9) and 24.6 for automated (95% CI 7.6 to 79.6). Negative likelihood ratios were 0.46 for visual dipstick testing (95% CI 0.29 to 0.71) and 0.47 for automated (95% CI 0.31 to 0.72). Conclusion: Automated dipstick testing was not superior to visual testing for detection of proteinuria in pregnant women in a primarily outpatient setting. Sensitivity may depend on the test strips and/or analyzer used. © 2014 Society of Obstetricians and Gynaecologists of Canada. Source


Rafii-Tari H.,Imperial College London | Lessoway V.A.,British Columbia Womens Hospital and Health Center | Kamani A.A.,University of British Columbia | Abolmaesumi P.,University of British Columbia | Rohling R.,University of British Columbia
Ultrasound in Medicine and Biology | Year: 2015

Despite the common use of epidural anesthesia in obstetrics and surgery, the procedure can be challenging, especially for obese patients. We propose the use of an ultrasound guidance system employing a transducer-mounted camera to create 3-D panorama ultrasound volumes of the spine, thereby allowing identification of vertebrae and selection of puncture site, needle trajectory and depth of insertion. The camera achieves absolute position estimation of the transducer with respect to the patient using a specialized marker strip attached to the skin surface. The guidance system is validated first on a phantom against a commercial optical tracking system and then invivo by comparing panorama images from human subjects against independent measurements by an experienced sonographer. The results for measuring depth to the epidural space, intervertebral spacing and registration of interspinous gaps to the skin prove the potential of the system for improving guidance of epidural anesthesia. The tracking and visualization are implemented in real time using the 3D Slicer software package. © 2015 World Federation for Ultrasound in Medicine & Biology. Source

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