Protocol-directed insulin infusion sliding scales improve perioperative hyperglycaemia in critical care

Continuous ex vivo glucose sensing in human physiological fluids using an enzymatic sensor in a vein replica

Managing blood glucose can affect important clinical outcomes during the intraoperative phase of surgery. However, currently available instruments for glucose monitoring during surgery are few and not optimized for the specific application. Here we report an attempt to exploit an enzymatic sensor in a vein replica that could continuously monitor glucose level in an authentic human bloodstream. First, detailed investigations of the superficial venous systems of volunteers were carried out using ocular and palpating examinations, as well as advanced ultrasound measurements. Second, a tubular glucose-sensitive biosensor mimicking a venous system was designed and tested. Almost ideal linear dependence of current output on glucose concentration in phosphate buffer saline was obtained in the range 2.2-22.0 mM, whereas the dependence in human plasma was less linear. Finally, the developed biosensor was investigated in whole blood under homeostatic conditions. A specific correlation was found between the current output and glucose concentration at the initial stage of the biodevice operation. However, with time, blood coagulation during measurements negatively affected the performance of the biodevice. When the experimental results were remodeled to predict the response without the influence of blood coagulation, the sensor output closely followed the blood glucose level.

Modelling the use of variable rate intravenous insulin infusions in hospitals by comparing Work as Done with Work as Imagined

BACKGROUND

Variable rate intravenous insulin infusions (VRIIIs) are widely used to treat elevated blood glucose (BG) in adult inpatients who are severely ill and/or will miss more than one meal. VRIIIs can cause serious harm to the patient if used incorrectly. Recent safety initiatives have embraced the Resilient Health Care (RHC) approach to safety by understanding how VRIIIs are expected to be used (Work as Imagined, 'WAI') and how it is actually used in everyday clinical care (Work as Done, 'WAD').

OBJECTIVES

To systematically compare WAI and WAD and analyse adaptations used in situ to develop a model explaining VRIII use.

METHODS

A qualitative observational study video-recording healthcare practitioners using VRIII. The video data were transcribed and inductively coded to develop a hierarchical task analysis (HTA) to represent WAD. This HTA was compared with a HTA previously developed to represent WAI. The comparison output was used to develop a model of VRIII use.

RESULTS

While many of the tasks in the WAD HTA were aligned with the tasks presented in the WAI HTA, some important ones did not. When misalignment was observed, permanent adaptations (e.g. signing as a witness for a changed VRIII's rate without independently verifying whether the new rate was appropriate) and temporary workarounds (e.g. not administering intermediate-acting insulin analogues although the intermediate-acting insulin prescription was not suspended) were the most frequently observed adaptations. The comparison between WAI and WAD assisted in developing a model of VRIII use. The model shed light on strategies used to imagine everyday work (e.g. incident reports, VRIII guidelines), how everyday work was accomplished (e.g. context-dependent adaptations) and how these contributed to both successful and unsuccessful outcomes.

CONCLUSIONS

This study provided in-depth understanding of the tasks required while using VRIIIs, and responses and adaptations needed to achieve safer care in a complex environment.