Wireless monitoring of liver hemodynamics in vivo

Liver transplants have their highest technical failure rate in the first two weeks following surgery. Currently, there are limited devices for continuous, real-time monitoring of the graft. In this work, a three wavelengths system is presented that combines near-infrared spectroscopy and photoplethysmography with a processing method that can uniquely measure and separate the venous and arterial oxygen contributions. This strategy allows for the quantification of tissue oxygen consumption used to study hepatic metabolic activity and to relate it to tissue stress. The sensor is battery operated and communicates wirelessly with a data acquisition computer which provides the possibility of implantation provided sufficient miniaturization. In two in vivo porcine studies, the sensor tracked perfusion changes in hepatic tissue during vascular occlusions with a root mean square error (RMSE) of 0.135 mL/min/g of tissue. We show the possibility of using the pulsatile wave to measure the arterial oxygen saturation similar to pulse oximetry. The signal is also used to extract the venous oxygen saturation from the direct current (DC) levels. Arterial and venous oxygen saturation changes were measured with an RMSE of 2.19% and 1.39% respectively when no vascular occlusions were induced. This error increased to 2.82% and 3.83% when vascular occlusions were induced during hypoxia. These errors are similar to the resolution of a commercial oximetry catheter used as a reference. This work is the first realization of a wireless optical sensor for continuous monitoring of hepatic hemodynamics. © 2014 Akl et al

Volunteer Bias in Recruitment, Retention, and Blood Sample Donation in a Randomised Controlled Trial Involving Mothers and Their Children at Six Months and Two Years: A Longitudinal Analysis

BACKGROUND: The vulnerability of clinical trials to volunteer bias is under-reported. Volunteer bias is systematic error due to differences between those who choose to participate in studies and those who do not. METHODS AND RESULTS: This paper extends the applications of the concept of volunteer bias by using data from a trial of probiotic supplementation for childhood atopy in healthy dyads to explore 1) differences between a) trial participants and aggregated data from publicly available databases b) participants and non-participants as the trial progressed 2) impact on trial findings of weighting data according to deprivation (Townsend) fifths in the sample and target populations. 1) a) Recruits (n = 454) were less deprived than the target population, matched for area of residence and delivery dates (n = 6,893) (mean [SD] deprivation scores 0.09[4.21] and 0.79[4.08], t = 3.44, df = 511, p<0.001). b) i) As the trial progressed, representation of the most deprived decreased. These participants and smokers were less likely to be retained at 6 months (n = 430[95%]) (OR 0.29,0.13-0.67 and 0.20,0.09-0.46), and 2 years (n = 380[84%]) (aOR 0.68,0.50-0.93 and 0.55,0.28-1.09), and consent to infant blood sample donation (n = 220[48%]) (aOR 0.72,0.57-0.92 and 0.43,0.22-0.83). ii) Mothers interested in probiotics or research or reporting infants' adverse events or rashes were more likely to attend research clinics and consent to skin-prick testing. Mothers participating to help children were more likely to consent to infant blood sample donation. 2) In one trial outcome, atopic eczema, the intervention had a positive effect only in the over-represented, least deprived group. Here, data weighting attenuated risk reduction from 6.9%(0.9-13.1%) to 4.6%(-1.4-+10.5%), and OR from 0.40(0.18-0.91) to 0.56(0.26-1.21). Other findings were unchanged. CONCLUSIONS: Potential for volunteer bias intensified during the trial, due to non-participation of the most deprived and smokers. However, these were not the only predictors of non-participation. Data weighting quantified volunteer bias and modified one important trial outcome. TRIAL REGISTRATION: This randomised, double blind, parallel group, placebo controlled trial is registered with the International Standard Randomised Controlled Trials Register, Number (ISRCTN) 26287422. Registered title: Probiotics in the prevention of atopy in infants and children

Understanding implementation and feasibility of tobacco cessation in routine primary care in Nepal: a mixed methods study

Background: By 2030, 80 % of the annual 8.3 million deaths attributable to tobacco will be in low-income countries (LICs). Yet, services to support people to quit tobacco are not part of routine primary care in LICs. This study explored the challenges to implementing a behavioural support (BS) intervention to promote tobacco cessation within primary care in Nepal. Methods: The study used qualitative and quantitative methods within an action research approach in three primary health care centres (PHCCs) in two districts of Nepal. Before implementation, 21 patient interviews and two focus groups with health workers informed intervention design. Over a 6-month period, two researchers facilitated action research meetings with staff and observed implementation, recording the process and their reflections in diaries. Patients were followed up 3 months after BS to determine tobacco use (verified biochemically) and gain feedback on the intervention. A further five interviews with managers provided reflections on the process. The qualitative analysis used Normalisation Process Theory (NPT) to understand implementation. Results: Only 2 % of out-patient appointments identified the patient as a smoker. Qualitative findings highlight patients' unwillingness to admit their smoking status and limited motivation among health workers to offer the intervention. Patient-centred skills needed for BS were new to staff, who found them challenging particularly with low-literacy patients (skill set workability). Heath workers saw cessation advice and BS as an addition to their existing workload (relational integration). While there was strong policy buy-in, operationalising this through reporting and supervision was limited (contextual integration). Of the 44 patients receiving the intervention, 27 were successfully followed up after 3 months; 37 % of these had quit (verified biochemically). Conclusions: Traditionally, primary health care in LICs has focused on acute care; with increasing recognition of the need for lifestyle change, health workers must develop new skills and relationships with patients. Appropriate and regular recording, reporting, supervision and clear leadership are needed if health workers are to take responsibility for smoking cessation. The consistent implementation of these health system activities is a requirement if cessation services are to be normalised within routine primary care

Parenteral anticoagulation may prolong the survival of patients with limited small cell lung cancer: a Cochrane systematic review

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

The learning effect of intraoperative video-enhanced surgical procedure training

BACKGROUND: The transition from basic skills training in a skills lab to procedure training in the operating theater using the traditional master-apprentice model (MAM) lacks uniformity and efficiency. When the supervising surgeon performs parts of a procedure, training opportunities are lost. To minimize this intervention by the supervisor and maximize the actual operating time for the trainee, we created a new training method called INtraoperative Video-Enhanced Surgical Training (INVEST). METHODS: Ten surgical residents were trained in laparoscopic cholecystectomy either by the MAM or with INVEST. Each trainee performed six cholecystectomies that were objectively evaluated on an Objective Structured Assessment of Technical Skills (OSATS) global rating scale. Absolute and relative improvements during the training curriculum were compared between the groups. A questionnaire evaluated the trainee's opinion on this new training method. RESULTS: Skill improvement on the OSATS global rating scale was significantly greater for the trainees in the INVEST curriculum compared to the MAM, with mean absolute improvement 32.6 versus 14.0 points and mean relative improvement 59.1 versus 34.6% (P = 0.02). CONCLUSION: INVEST significantly enhances technical and procedural skill development during the early learning curve for laparoscopic cholecystectomy. Trainees were positive about the content and the idea of the curriculum

The potential benefits of low-molecular-weight heparins in cancer patients

Cancer patients are at increased risk of venous thromboembolism due to a range of factors directly related to their disease and its treatment. Given the high incidence of post-surgical venous thromboembolism in cancer patients and the poor outcomes associated with its development, thromboprophylaxis is warranted. A number of evidence-based guidelines delineate anticoagulation regimens for venous thromboembolism treatment, primary and secondary prophylaxis, and long-term anticoagulation in cancer patients. However, many give equal weight to several different drugs and do not make specific recommendations regarding duration of therapy. In terms of their efficacy and safety profiles, practicality of use, and cost-effectiveness the low-molecular-weight heparins are at least comparable to, and offer several advantages over, other available antithrombotics in cancer patients. In addition, data are emerging that the antithrombotics, and particularly low-molecular-weight heparins, may exert an antitumor effect which could contribute to improved survival in cancer patients when given for long-term prophylaxis. Such findings reinforce the importance of thromboprophylaxis with low-molecular-weight heparin in cancer patients

From open radical hysterectomy to robot-assisted laparoscopic radical hysterectomy for early stage cervical cancer: aspects of a single institution learning curve

We analysed the introduction of the robot-assisted laparoscopic radical hysterectomy in patients with early-stage cervical cancer with respect to patient benefits and surgeon-related aspects of a surgical learning curve. A retrospective review of the first 14 robot-assisted laparoscopic radical hysterectomies and the last 14 open radical hysterectomies in a similar clinical setting with the same surgical team was conducted. Patients were candidates for a laparoscopic sentinel node procedure, pelvic lymph node dissection and open radical hysterectomy (RH) before August 2006 and were candidates for a laparoscopic sentinel node procedure, pelvic lymph node dissection and robot-assisted laparoscopic radical hysterectomy (RALRH) after August 2006. Overall, blood loss in the open cases was significantly more compared with the robot cases. Median hospital stay after RALRH was 5 days less than after RH. The median theatre time in the learning period for the robot procedure was reduced from 9 h to less that 4 h and compared well to the 3 h and 45 min for an open procedure. Three complications occurred in the open group and one in the robot group. RALRH is feasible and of benefit to the patient with early stage cervical cancer by a reduction of blood loss and reduced hospital stay. Introduction of this new technique requires a learning curve of less than 15 cases that will reduce the operating time to a level comparable to open surgery

Robot-assisted surgery for the management of apical prolapse: a bicentre prospective cohort study

Objective: Robot‐assisted surgery is a recognized treatment for pelvic‐organ prolapse. Many of the surgical subgroup outcomes for apical prolapse are reported together leading to a paucity of homogenous data. Design: Prospective observational cohort study (https://clinicaltrials.gov; identifier NCT01598467) assessing outcomes for homogeneous subgroups of robot‐assisted apical prolapse surgery. Setting: Two European tertiary referral hospitals. Population: Consecutive patients undergoing robot‐assisted sacrocolpopexy (RASC) and supracervical hysterectomy with sacrocervicopexy (RSHS). Methods: Anatomical cure (simplified Pelvic Organ Prolapse Quantification (sPOPQ) stage 1,), subjective cure (symptoms of bulge) and quality of life (Pelvic Floor Impact Questionnaire [PFIQ‐7]). Main Outcome measures: Primary outcome: anatomical and subjective cure. Secondary outcomes: surgical safety and intraoperative variables. Results: Total 305 patients included (RASC N=188, RSHS N=117). Twelve months follow‐up available for 144 (RASC 76.6%) and 109 (RSHS 93.2%). Anatomical success of the apical compartment occurred in 91% (RASC) and in 99% (RSHS). In all compartments, success percentages were 67% and 65% respectively. Most recurrences were anterior compartment (15.7% RASC [symptomatic 12.1%]; 22.9% RSHS [symptomatic 4.8%]). Symptoms of bulge improved from 97.4% to 17.4% (p<0.0005). PFIQ‐7 scores improved from 76.7 ± 62.3 to 13.5 ± 31.1 (p<0.0005). Duration of surgery increased significantly in RSHS (183.1 ± 38.2 versus 145.3 ± 29.8 [p<0.0005]). Intraoperative complications and conversion rates were low (RASC: 5.3% and 4.3%; RSHS: 0.0% and 0.0%). Four severe postoperative complications occurred after RASC (2.1%) and one after RSHS (1.6%). Conclusion: This is the largest reported prospective cohort study on robot‐assisted apical prolapse surgery. Both procedures are safe, with durable results

Evidence in the learning organization

<p>Abstract</p> <p>Background</p> <p>Organizational leaders in business and medicine have been experiencing a similar dilemma: how to ensure that their organizational members are adopting work innovations in a timely fashion. Organizational leaders in healthcare have attempted to resolve this dilemma by offering specific solutions, such as evidence-based medicine (EBM), but organizations are still not systematically adopting evidence-based practice innovations as rapidly as expected by policy-makers (the knowing-doing gap problem). Some business leaders have adopted a systems-based perspective, called the learning organization (LO), to address a similar dilemma. Three years ago, the Society of General Internal Medicine's Evidence-based Medicine Task Force began an inquiry to integrate the EBM and LO concepts into one model to address the knowing-doing gap problem.</p> <p>Methods</p> <p>During the model development process, the authors searched several databases for relevant LO frameworks and their related concepts by using a broad search strategy. To identify the key LO frameworks and consolidate them into one model, the authors used consensus-based decision-making and a narrative thematic synthesis guided by several qualitative criteria. The authors subjected the model to external, independent review and improved upon its design with this feedback.</p> <p>Results</p> <p>The authors found seven LO frameworks particularly relevant to evidence-based practice innovations in organizations. The authors describe their interpretations of these frameworks for healthcare organizations, the process they used to integrate the LO frameworks with EBM principles, and the resulting Evidence in the Learning Organization (ELO) model. They also provide a health organization scenario to illustrate ELO concepts in application.</p> <p>Conclusion</p> <p>The authors intend, by sharing the LO frameworks and the ELO model, to help organizations identify their capacities to learn and share knowledge about evidence-based practice innovations. The ELO model will need further validation and improvement through its use in organizational settings and applied health services research.</p