Design and development of ferrocene-containing chitosan-cografted-branched polyethylenimine redox conjugates for monitoring free flap failure after reconstructive surgery

We reported a proof-of-concept study of developing an electrochemical biosensor for prolonged continuous monitoring free flap failure caused by vascular occlusion after reconstructive surgery. Ferrocene (Fc)-containing Chitosan-cografted-Branched Polyethylenimine redox conjugates (CHIT-Fc-co-BPEI-Fc) were used as pH-tuneable matrix to attach the target enzymes (glucose oxidase ≡ GOD and lactate oxidase ≡ LOD, respectively) to build up the corresponding GOD-sensor and LOD-sensor. The sensitivity of GOD-/LOD-sensor was found to be 2.89(±0.06)μA/mM and 2.95(±0.19)μA/mM with a limit of detection (LOD) of 0.047 mM and 0.172 mM, respectively. The sensor performance was further pre-clinically validated via rabbit study, which confirmed that the designed biosensors could electrochemically detect the changes of metabolite levels caused by flap failure within minutes. This sensor protocol is able to be fabricated as embedded biosensor for prolong continuous detection for clinical application/research.

Automated measures of hand hygiene compliance among healthcare workers using ultrasound: validation and a randomized controlled trial

OBJECTIVE

The primary objective of this study was to validate a novel method of assessing hand hygiene compliance using ultrasound transmitters in patient zones and staff tagged with receivers. The secondary objective was to assess the impact of audio reminders and quantified individual feedback.

DESIGN

An observational comparison against manual assessment followed by assessment using an open-label randomized control method.

SETTING

Patient zones were established in 3 wards of 2 large teaching hospitals, including 88 general and 18 intensive care unit ward beds.

PARTICIPANTS

Consented regular ward nursing, medical, and allied health staff.

METHODS

Concordance between 40 hours of manual observation using trained hand hygiene auditors and automated measures of opportunities and compliance. Subsequent measured interventions were reminder beeps and written individual feedback.

RESULTS

When compared with manual observations, ultrasound monitoring underestimated percentage compliances by a nonsignificant mean (95% confidence interval [CI]) difference of 5.2% (-20.1% to 9.8%; [Formula: see text]). After the intervention, adjusted multivariate analysis showed mean (95% CI) overall compliance in the intervention arm was 6.8% (2.5%-11.1%; [Formula: see text]) higher than in the control arm. Results stratified by compliance at entry and exit showed that the effect of intervention was stronger for compliance at exit than at entry.

CONCLUSIONS

Our automated measure of hand hygiene compliance is valid when compared with the traditional gold standard of manual observations. As an interventional tool, ultrasound-based automated hand hygiene audits have significant benefit that can be built upon with enhancements and find increasing acceptance with time.