•  perioperative BG targets are generally between 4 - 8 mmol/L

•   whenever possible, arrange for the patient with diabetes to be scheduled early in the AM to minimize disruptions to their usual insulin regimen


When to consider using IV insulin perioperatively:

•   for patients on large amounts of insulin (e.g. > 50 U/day) who will be NPO for extensive period of time or for major surgical procedure lasting > 2 hrs (e.g. cardiothoracic, abdominal, transplant, neurological or vascular surgery)

•   patients with type 1 diabetes

•  uncontrolled hyperglycemia preoperatively

•  peripartum period


How to start IV insulin:

•   specify how you want the IV insulin to be mixed.  Usual practice is to mix 50 units of Humulin R in 500 cc of D5W (i.e. 1 U per 10 mL)

• give concurrent D5W at 75-100 cc/h (or rate depending on volume status)

•  start insulin infusion at 0700h, order capillary glucose monitoring q1h

•   calculate starting IV insulin rate (U/hr):   ½ of Total Daily Dose / 24

•   use this rate as the infusion rate for your target BG range.  In the perioperative period, this is generally in the 4-8 mmol/L range

•   set parameters to increase or decrease the rate for BG values above or below the target range



Calculate an initial IV insulin rate for patient who is on Humalog 10 units ac meals and glargine 20 units qhs



Total daily dose = (10x3) units + 20 units

                          = 50 units


Initial hourly rate = (50 units/day ÷ 2)

                                        24 h/day

                            1.0 units/h


Adjusting scale can appear such as the example below: 


Blood glucose (mmol/L)

Humulin R infusion rate (units/hr)


Stop infusion, call MD and give ½ amp of D50W




+ 0.5 (i.e. 1.5 U/h)


+1.0 (i.e. 2.0 U/h)


+1.5 (i.e. 2.5 U/h)


+2.0 (i.e. 3.0 U/h)


+2.5 (i.e. 3.5 U/h)


+3.0 (i.e. 4 U/h) and call MD


If the starting insulin infusion rate is higher (e.g. 3.0 U/h or more) the increment changes for each tier of glucose could be more (i.e. +1.0, +2.0, +3.0, etc.)

Always reassess the IV insulin orders and adjust as necessary if it is ineffective.



•  do NOT forget to resume pt’s usual insulin regimen once they are eating (it would be a good idea to highlight this in the sign-out)


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