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Background The clinical efficacy of effect-site targeted patient-maintained propofol sedation (PMPS) compared to anaesthetist-controlled propofol sedation (ACPS) for patients undergoing awake joint replacement surgery is currently unknown. There is no commercially available medical device capable of delivering PMPS so we have designed and built such a device. We plan a clinical trial to compare PMPS to ACPS and to collect data relating to the safety of our prototype device in delivering sedation. Methods The trial is an open-label, randomised, controlled superiority trial recruiting adults who are undergoing elective primary lower-limb arthroplasty with sedation by propofol infusion by effect-site targeting into two equal-sized parallel arms: PMPS and ACPS. The primary research objective is to compare the body-weight-normalised rate of propofol consumption when sedation for surgery on adults undergoing elective primary lower-limb arthroplasty under spinal anaesthesia is patient-maintained versus when it is anaesthetist-controlled. The study primary null hypothesis is that there is no difference in the rate of propofol consumption when sedation is patient-maintained versus anaesthetist-controlled. Discussion This is the first trial to test the superiority of effect-site-targeted patient-maintained propofol sedation versus anaesthetist-controlled propofol sedation in terms of total propofol consumption during the sedation period. The results of this trial will help inform clinicians and device manufacturers of the clinical efficacy and safety of patient-maintained propofol sedation applied to a common operative setting. Trial registration International Standard Randomised Controlled Trial Number Registry, ISRCTN29129799 . Prospectively registered on 12 June 2018. Electronic supplementary material The online version of this article (10.1186/s13063-019-3228-4) contains supplementary material, which is available to authorized users.

Magnetoencephalography (MEG) has been revolutionised in recent years by optically pumped magnetometers (OPMs). “OPM-MEG” offers higher sensitivity, better spatial resolution and lower cost than conventional instrumentation based on superconducting quantum interference devices (SQUIDS). Moreover, OPMs offer the possibility of motion robustness and lifespan compliance, dramatically expanding the range of MEG applications. However, OPM-MEG remains nascent technology; it places stringent requirements on magnetic shielding, and whilst a number of viable systems exist, most are custom made and there have been no cross-site investigations showing the reliability of data. In this paper, we undertake the first cross-site OPM-MEG comparison, using near identical commercial systems scanning the same participant. The two sites are deliberately contrasting, with different magnetic environments: a “green field” campus university site with an OPM-optimised shielded room (low interference) and a city centre hospital site with a “standard” (non-optimised) MSR (high interference). We show that despite a 25-fold difference in background field, and a 30-fold difference in low frequency interference, using dynamic field control and software-based suppression of interference we can generate comparable noise floors at both sites. In human data recorded during a visuo-motor task and a face processing paradigm, we were able to generate similar data, with source localisation showing that brain regions could be pinpointed with just ~10 mm spatial discrepancy and temporal correlations of > 80%. Overall, our study demonstrates that “plug- and-play” OPM-MEG systems exist and can be sited even in challenging magnetic environments.

Titanium alloy based maxillofacial plates and implants are widely used in fracture treatment and reconstructions. Filler materials Graphene Nanoplatlets(GNPs) were used in Titanium alloy maxillofacial plate and a Finite Element Model (FEM) was designed to reconstruct a fractured human mandible. 50N and 500N bite forces were applied on the mandible and stress distribution using Von mises failure theory across the plate sections was analyzed. A pure plate was critically stressed at a section near the mandible fracture region for a Von mises stress of nearly 27.5GPa while this stress got reduced by nearly 10%-22% with the presence of minor composition of GNPs in the plate. GNPs orientation in parallel (21.1 GPa) to the plate axis were more effective in comparison to other orientations(90 0 ,45 0 and 135 0) and the location variation of these GNPs along the plate had no significant effect on the stress distribution. The fatigue analyses showed that, under these stresses and forces the plate with GNP was able to endure for nearly 7000 days, while pure Titanium plate could fail by fatigue in approximately 70 days. Hence, presence of minor compositions of GNPs could enhance endurance life of the Titanium plate by reducing stress concentrations at critical sections of the plate.

Background: Patient-maintained propofol TCI sedation (PMPS) allows patients to titrate their own target-controlled infusion (TCI) delivery of propofol sedation using a handheld button. The aim of this RCT was to compare PMPS with anaesthetist-controlled propofol TCI sedation (ACPS) in patients undergoing elective primary lower-limb arthroplasty surgery under spinal anaesthesia. Methods: In this single-centre open-label investigator-led study, adult patients were randomly assigned to either PMPS or ACPS during their surgery. Both sedation regimes used Schnider effect-site TCI modelling. The primary outcome measure was infusion rate adjusted for weight (expressed as mg kg À1 h À1 ). Secondary outcomes measures included depth of sedation, occurrence of sedation-related adverse events and time to medical readiness for discharge from the postanaesthsia care unit (PACU). Results: Eighty patients (48 female) were randomised. Subjects using PMPS used 39.3% less propofol during the sedation period compared with subjects in group ACPS (1.56 [0.57] vs 2.57 [1.33] mg kg À1 h À1 ; P<0.001), experienced fewer discrete episodes of deep sedation (0 vs 6; P¼0.0256), fewer airway/breathing adverse events (odds ratio [95% confidence interval]: 2.94 [1.31e6.64]; P¼0.009) and were ready for discharge from PACU more quickly (8.94 [5.5] vs 13.51 [7.2] min; P¼0.0027). Conclusions: Patient-maintained propofol sedation during lower-limb arthroplasty under spinal anaesthesia results in reduced drug exposure and fewer episodes of sedation-related adverse events compared with anaesthetist-controlled propofol TCI sedation. To facilitate further investigation of this procedural sedation technique, PMPS-capable TCI infusion devices should be submitted for regulatory approval for clinical use. Clinical trial registration: ISRCTN29129799.

Abbreviations:(NPs) Nanoplatlets (NTs) Nanotubes Nanoparticles in the form nanotubes and nanoplatlets have been compared for Von Mises stresses by using them as low composition reinforcements in Titanium alloy based mandible plate for different compositions and orientations.A Finite Element Model (FEM) has been designed to reconstruct a fractured human mandible with a Titanium alloy mandible plate. A 500N compressive force was applied on the mandible and stress distribution across the plate sections was analysed for aligned 2D random and 3D random orientations for both tubes and platlets. Carbon material as graphene has been used for tube and platlet in the form of Nanotubes (NTs) and Nanoplatlets (NPs) respectively. Using properties of graphene as the filler in Titanium alloy plate, for both NPs and NTs, the stresses reduced between 5% to 25% for NPs and NTs Graphene-Titanium composite plates in comparison to pure plates, at critically stressed sections. NTs exhibited stress reduction of nearly 23.4 % for aligned configurations while NPs exhibited stress reduction up to 21.2 % for 2D and 3D random configurations in comparison to pure Titanium plates. Hence, it has been suggested that nanotubes exhibited superior mechanical reinforcement potential beyond that of nanoplatelets for aligned, while nanoplatelets provided enhanced mechanical reinforcements for random configurations. Therefore, for biomedical implant applications nanocomposite materials can be designed with the same dimensional form but with lower compositions of filler materials by simply manipulating the appropriate orientations.

Each year, many operations in the UK are performed with the patient awake, without the use of general anaesthesia. These include joint replacement procedures, and in order to reduce patient anxiety, the supervising anaesthetist delivers the sedative propofol intravenously using a target-controlled infusion (TCI) device. However, it is clinically challenging to judge the required effect-site concentration of sedative for an individual patient, resulting in patient care issues related to over or under-sedation. To improve the process, patient-maintained propofol sedation (PMPS), where the patient can request an increase in concentration through a hand-held button, has been considered as an alternative. However, due to the proprietary nature of modern TCI pumps, the majority of PMPS research has been conducted using prototypes in research studies. In this work, a PMPS system is presented that effectively converts a standard infusion pump into a TCI device using a laptop with TCI software. Functionally, the system delivers sedation analogous to a modern TCI pump, with the differences in propofol consumption and dosage within the tolerance of clinically approved devices. Therefore, the Medicines and Healthcare products Regulatory Agency (MHRA) has approved the system as a safe alternative to anaesthetist-controlled TCI procedures. It represents a step forward in the consideration of PMPS as a sedation method as viable alternative, allowing further assessment in clinical trials.