PERIOPERATIVE/IV INSULIN 

 

•  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

 

Example:

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

 

Answer:    

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)

0-4.0

Stop infusion, call MD and give ½ amp of D50W

4.1-8.0

1.0

8.1-10.0

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

10.1-12.0

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

12.1-14.0

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

14.1-16.0

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

16.1-18.0

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

>18

+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.

 

Housekeeping:

•  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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