POTD: Insulin in the ER

Today’s POTD is brought to you by the fear and terror I feel every time I have to order insulin, so below I’m going to review the different types of insulin, when to use them, and importantly how to order them. 

Types of Insulin

There are four main classes of insulin: rapid-acting, short-acting, intermediate-acting, and long-acting. These classes are aptly named based on their onset time. Here is a summary of each class:

I know what you’re thinking – wow, that is a lot of options… which one do I chose?! How much do I give?! Do I give it subcutaneously or intravenously?! Well, luckily, the Maimo pharmacists simplified things for us by only having three types of insulin (lispro, glargine, and regular) and very thorough order sets. If you know your indication, SCM guides you through the rest.

Insulin administration comes in two flavors: subcutaneous and intravenous. Subcutaneous is the only dosage route for long-acting insulin but rapid and short-acting insulin can be given subcutaneous or intravenous. IV insulin should only be used when you are treating hyperkalemia, DKA or HHS. Otherwise, you should give insulin subq.

Dosage of insulin depends on the patient’s weight, blood glucose level, and insulin tolerance. This can be a lot to remember, so your best bet is to follow the order sets that I’ll go through next.

 Acute Hyperglycemia (without evidence of DKA or HHS) can be managed with subq lispro (as well as IV fluids and addressing the underlying cause). The amount of insulin you give depends on the patient’s current glucose level and their sensitivity or resistance to insulin. Be sure to ask what their home insulin regimen is before ordering. Then you can easily order through the “Insulin Subcutaneous Ordering” order set.

• Search for and open the order set “Insulin Subcutaneous Ordering”

• Select the patients feeding status – eating, tube feeding or NPO

• Scroll down to the “correction scale insulins” section and decide between very low dose, low dose, moderate dose, or high dose based on your patient’s home insulin regimen

  • Very low dose = for patients who are insulin naïve

  • Low dose = for patients who require less than 40 units per day

  • Moderate dose = for patients who require 40-80 units per day

  • High dose = for patients who require more than 80 units per day 

• Check the “insulin lispro correction scale injectable” under the appropriate dosing regimen. If you want to give a one-time dose in the ED double click the order to change the frequency from “3x/day, before meals” to “once” and make the start time “STAT”

DKA or HHS is treated with an IV infusion of regular insulin. We start the drip at 0.1 units/kg/hour and continue until the gap is closed. You may precede the drip with a bolus of IV lispro at 0.1 units/kg, but there is no evidence that giving a bolus is beneficial, and it can potentially cause hypoglycemia. Once the gap is closed, you can transition your patient to subq insulin by calculating the total amount of insulin administered IV and then give 50% of that total as subq glargine insulin.  (Of course, there are many other aspects of DKA/HHS management which could be a separate POTD; I’m just highlighting some key points here.)

• Search for and open the order set “ED DKA/HHS Ordering”

• Scroll down to “insulin” and check the “insulin 100 units in NS 100ml” infusion. You will need to double click the order to input a dose.

  • Of note, the dose is listed as units/hr and should be calculated as 0.1u/kg/hr. If your patient weighs 70kg, you would give 7 units per hour.

• If you want to bridge to subq insulin, go back to the same “ED DKA/HHA Ordering” but scroll down to “basal/long acting insulin”

• Select “insulin glargine (100 units/ml) basal." Double click the order to input a dose.

  • Remember the dose will be 50% of the total IV insulin given.

Hyperkalemia is treated with a rapid bolus of IV insulin intended to shift potassium into the cells. Be sure to give this insulin with dextrose to prevent hypoglycemia.

• Search for the “ED Hyperkalemia Order Set”

• Select “insulin lispro (100units/ml) injectable IV push”

  • This will default to a dose of 5 units. You can re-dose again if needed. 

Sources:

Our lovely ED Pharmacy team

https://www.uptodate.com/contents/general-principles-of-insulin-therapy-in-diabetes-mellitus?search=insulin&source=search_result&selectedTitle=2%7E150&usage_type=default&display_rank=1

https://rushem.org/2021/05/16/basic-management-of-diabetesnot-just-for-internists/

https://rebelem.com/benefit-initial-insulin-bolus-diabetic-ketoacidosis/

POTD: Dextrose Containing Fluids

During my very brief stint as your TR I have received two separate requests to discuss dextrose-containing fluids so for today’s POTD we’re going to review the use of these dextrose fluids based on their various formulations. 

Dextrose containing fluids are often used in the management of hypoglycemia. Hypoglycemia is defined as an abnormally low plasma glucose level, typically below 60 or 70 mg/dl in adults. Oral repletion is preferred in patients who are awake, alert, and able to swallow. However, for patients with severe hypoglycemia or altered mental status, you likely need to give intravenous dextrose containing fluids. These fluids are commonly referred to by the percent of glucose present in the solution, such as D50, D10, D5, etc.

D50 contains 25g of glucose in 50mL of water. This usually comes as a prefilled syringe and is commonly referred to as “an amp of D50.” Admittedly this is the dextrose containing fluid I find myself ordering the most for acute hypoglycemia. It is readily available (can be found in any of the ED omnicells) and provides a quick bolus of glucose with about five times the amount of glucose present in a normal adult’s blood. However, D50’s hypertonic nature increases the risk of vascular and tissue damage. If administered into a small vein D50 can be irritating and may cause thrombophlebitis. Additionally, it is also prone to extravasation from the vein leading to skin irritation and, in severe cases, local scarring or skin necrosis. Given these complications, some people advocate for the use of D10 instead.

D10 often comes as 10g of glucose in 100mL of fluid. This fluid has a lower osmolarity compared to D50, which reduces the risk of extravasation and thrombophlebitis. The lower concentration of D10 also allows for easier titration to ensure the patient becomes normoglycemic without overshooting and causing hyperglycemia. From my googles and discussions, the primary defense against using D10 in acute hypoglycemia seems to be a concern about the time required to give D10 as compared to D50. However, it’s important to note that one amp of D50 should be infused over 2-3 minutes to avoid extravasation. Studies show that a 200mL bolus of D10 (containing 20g of glucose) can be administered via pressure bag and will enter the patient’s bloodstream as quickly as slow pushing an amp of D50 (containing 25g of glucose). At Maimo, D10 can be found in the ED pharmacy, but after pharmacy leaves at night you would have to get it sent down from central pharmacy (unless you’re in peds, where there is usually a few bag of D10). 

Speaking of pediatrics… the treatment of hypoglycemia is slightly different in children. To minimize vascular complications associated with highly concentrated dextrose fluids, we opt for using weight based volumes of more dilute fluids, such as D10 or D25.

The general rule of thumb is neonates and infants (less than 1 year old) should get D10, while toddlers and children (1-8 years old) should get D25. Adolescents (greater than 8 years old) can be given D50. Regardless of the dextrose concentration, the volume administered should provide 0.5g dextrose per kg. To conveniently calculate the dose in milliliters, we use the “Rule of 50” – multiply the type of dextrose solution by a factor of 5, 2, or 1 (ml/kg) to give a total of 50.

• D10: 10 x 5 = 50, so give 5ml/kg

• D25: 25 x 2 = 50, so give 2ml/kg

• D50: 50 x 1 = 50, so give 1ml/kg

Overall these rules can be summarized as:

• Neonates and infants <1 YO, give D10 at 5 ml/kg

• Toddlers and children 1-8 YO, give D25 at 2ml/kg

• Adolecents > 8YO, give D50 at 1ml/kg

Of note, we do not have D25 fluids in the Maimo ER so usually I’ve seen people give D10 regardless of the patient’s age. Though you can always get D25 from PICU or central pharmacy in a pinch you can always make it out of an amp of D50. To make D25, discard 25mL from the D50 ampule and then add 25mL of NS or sterile water back into the ampule. Similarly, to make D10, discard 40mL from the D50 ampule and replace it with 40mL of NS or sterile water.

And last but not least, D5 is another fluid option with 5g of dextrose in 100ml of fluid. This is another commonly used dextrose-containing fluid that can be found in all the ED Omni cells. However, this fluid is too dilute to be recommended as a bolus treatment for acute hypoglycemia. Instead, where it shines is as a maintenance fluid to maintain normoglycemia and prevent rebound hypoglycemic events.

Sources:

https://www.emdocs.net/em3am-hypoglycemia/

https://www.aliem.com/d50-vs-d10-severe-hypoglycemia-emergency-department/

https://pemcincinnati.com/blog/521-50-dextrose-volume-hypoglycemia/

POTD: Ultrasound Guided Access

A few weeks ago one of our lovely interns asked me “how do you know when to put in an ultrasound IV versus a midline?” To which I replied, “blood pressure and vibes.” But in hindsight… I fear that may not be the most helpful answer so I’m going to spend today’s POTD reviewing the various intravenous catheters we place under ultrasound guidance and when to use them.

Ultrasound-guided IV: This is your typical peripheral catheter placed into a vein (usually the upper arm) for the purpose of blood draws, medication administration, and contrast infusion. These are indicated in patients who have poor vasculature such that our excellent nurses can’t obtain IV access. You can theoretically place any size catheter, but most often you will use an 18g or 20g. 

Midline: An intermediate between an ultrasound guided IV and a central line. Like an ultrasound IV, they are placed in a large vein in the patient’s upper arm. However, it’s longer and has thicker walls than a peripheral IV catheter which reduces the risk of the line getting dislodged. Thus, midlines can be used for medications with high risk for extravasation (i.e. vasopressors, calcium chloride, hypertonic saline). When placing a midline, you should maintain a sterile field as these can be left in for weeks. At Maimo we have both single lumen (3Fr with one 18g channel x 10cm long) and double lumen (4 Fr with two 18g channels x 20cm long) midlines. Single lumens are slightly easier, faster, and less painful to insert. Double lumens allow you to give multiple medications simultaneously. Before inserting a midline assess the current and anticipated needs of your patient to decide if they need a single or double lumen. Some people opt to place a midline in any north side patient who is ill-appearing and definitely getting admitted to save you and the patient from future pokes.

Now here’s where things can get confusing because we use multiple terms to describe very similar procedures so stick with me here…

Central Venous Line: Triple lumen catheter placed into the internal jugular, subclavian, or femoral vein. These catheters are versatile and can be used for various purposes, including medication administration, blood draws, fluid resuscitation, and hemodynamic monitoring. They are useful for patients who require more secure and definitive access compared to a midline, or when a midline can’t obtained. Triple lumen CVCs are typically 20cm long and have a 7Fr diameter, with one 16g and two 18g channels.  

Trialysis: Another triple lumen catheter placed into the internal jugular, subclavian or femoral vein. This catheter is unique from the above CVC due to its larger channels which have a 13Fr diameter, with one 17g and two 12g channels. The larger diameter allows the trialysis to be used for all the typical central line indications plus dialysis.

Cordis: Large bore single lumen catheter placed in the internal jugular, subclavian, or femoral vein. Unlike the CVC and trialysis, the cordis is shorter (10cm long) with a larger diameter (9Fr with one 11g channel). This allows the cordis to have a much higher flow rate compared to other lines, so it is placed in patients requiring rapid transfusion, usually of large volume blood products.