Perioperative variable rate intravenous insulin infusion: a quality improvement project on a vascular surgery ward

Variable rate intravenous insulin infusion (VRIII) is used perioperatively to maintain normoglycaemia in patients with diabetes who are undergoing surgery. The aims of this project were as follows: (1) to audit the extent to which perioperative prescribing of VRIII for diabetic vascular surgery inpatients at our hospital meets established standards and (2) to use the results of the audit to guide improvement in the quality and safety of prescribing practices and reduce VRIII overuse.

Vascular surgery inpatients who had perioperative VRIII were included in the audit. Baseline data were collected consecutively from September to November 2021. There were three main interventions: a VRIII Prescribing Checklist, education of junior doctors and ward staff, and electronic prescribing system updates. Postintervention and reaudit data were collected consecutively from March to June 2022.

The number of VRIII prescriptions totalled 27 in preintervention, 18 in postintervention and 26 in reaudit periods. Prescribers used the 'refer to paper chart' safety check more frequently postintervention (67%) and on reaudit (77%) compared with preintervention (33%) (p=0.046). Rescue medication was prescribed in 50% of postintervention and 65% of reaudit cases compared with 0% preintervention (p<0.001). Intermediate/long-acting insulin was appropriately amended more often in the postintervention versus preintervention period (75% vs 45%, p=0.041). Overall, VRIII was appropriate for the situation in 85% of cases.

The quality of perioperative VRIII prescribing practices improved following the proposed interventions, with prescribers more frequently using recommended safety measures such as 'refer to paper chart' and rescue medication. There was a marked sustained improvement in prescriber-initiated adjustment of oral diabetes medications and insulins. VRIII is occasionally administered unnecessarily in a subset of patients with type 2 diabetes and may be an area for further study.