Fasting before Surgery: What have you been told?

I’m having myself a little surgery in 11 days, and I’m starting to make some preparations. Went in for the pre-op consultation today and talked details with the surgeon. He passed me a piece of paper with my preparation instructions, and I scanned immediately for the fasting times. The dreaded fasting times.

Just about every surgery I’ve ever had has occurred after my developing diabetes, so I have no recollection of what they tell a non-D. My guess is it’s much the same… Nothing past midnight… and maybe nothing but clear liquids until 4 hours before… and nothing at all inside of that. I get that few people like fasting before surgery, but this has always been a nightmare for me, and my strategy, absurd as it was, was always to just jack up my numbers so there was no chance of a crash. For obvious reasons, that’s just dumb. And I won’t do that anymore. Also of note is that only within the last couple of years has a medical professional somewhere along the way taught me it’s okay to take glucose tablets even while fasting… And that’s helped. As has being on a pump… So now I just feel like I’m complaining, but I still want to ask the question. As diabetics, what are you guys asked to do regarding fasting? Has it always been the standard? Have you ever had a doctor make accommodations in any way? I will offer up that I have had a couple of doctors make accommodations, and because they’ve ever been made, I can’t understand why they can’t always be made. And I am talking about for general anesthesia.

I know I’m rambling, but this has been on my mind for many years… and this is why it’s so frustrating. Most places will tell you to fast past midnight regardless of the time of your surgery. So if your surgery is at 8:00 am, fine, 8 hrs. If it’s at 12:00 pm… 12 hours. Ask if it’s okay to eat until 4:00 am, and they look at you like you’re out of control.

This isn’t important, and I really can handle the fasting now so I’m not sure why I’m posting at all, I’ve just been curious a long time. It has felt to me that fasting for these set times maybe could be more flexible.

Still rambling.


In my experience they will deliberately schedule diabetics for first thing in the morning to minimize fasting times, instruct them to take no bolus insulin after midnight, and eat nothing after midnight. They’ve also told me that clear liquids with sugar (eg apple juice) is ok if necessary… this isn’t their first rodeo, I bet you wouldn’t believe what percentage of their patients are on insulin… you’ll be ok!


I just had surgery on the 14th of August, I had to get clearance from my endocrinologist and my cardiologist, I had to stop my warafin 5 days before and endo wanted me to be stable at around 130 at surgery start, the aniestegologis actually wanted training from me on my cgm and checked while I was under.
Now for your question, I was on clear diet the day before with nothing 6 hours before, I survived on jello and gatorade. Then clear diet afterward, was kept in for two days afterward. Surgery lasted over 5 hours, after 3 hours they put me on glocuse drip.
Hope yours goes better than expected.


@Nickyghaleb. My last 4 surgeries I have had to fast, one for 14 hours. The Endo\Surgery team was explicit regarding my insulin use pre-surgery. What happens before I arrive is what happens, with the caveat that I would not show up to surgery with a bg higher than 250. Period. I made basal bolus corrections as needed up until I checked in. On one surgery I still had 4 units IOB pre-op. I also spent extra time with the anesthesiologist showing him\her how to operate the pump and use the Dexcom. I stayed tethered to my pump and Dexcom the entire time.

My basal is well tuned, and I was able to fast with minor if any corrections. On one surgery they did allow me to inhale a pack of Smarties just before the pre-op nurse checked me in. Regarding food, the biggest concern is undigested food in your stomach that could regurgitate and choke you during anesthesia.

Liquids, including coffee more than 4 hours before surgery were fine. I found the pre-op nurses to be very accommodating with my blood sugar’s as long as I was able to demonstrate that I was able to tightly control them.

The recovery nurses were also great, except they kept pushing high sugar items post op. (They were awesome with the fentanyl though…)

Nikki you’ll pull through this with flying colors just because you are Nikki. I hope for you a speedy recovery with very little or no pain. I’m around if you need someone to yell at, LOL. I’m here for you, whatever you need.


Thank you, @Sam, @T1john, and @elver. That’s all good information…and some very kind words. I didn’t realize I was nervous. :roll_eyes:

I was going to stay up and respond to everything, but I think I’ll make myself shut out the lights and drift off with your positive thoughts. Argue with you guys tomorrow. :thinking:

Just kidding. :grin:

What time is your surgery?

You don’t normally eat when you are asleep, right? So there is nothing different there.

So what are the specifics of the schedule?

I mean, eat dinner, maybe have a little sugar at night if you need it for low BG, and go to sleep. The only difference might be skipping breakfast before you go to the hospital.

I’d suggest cutting your basal by 20% at night and then go to 0% an hour before surgery.


My endo advised me to go to 50% basal when I wake the morning of the surgery, and correct to a normal in-range BG. That worked ok for me.


8:00 am—arrive at 6. I know this is going to be fine. It’s just not my favorite thing to do, and I have a long history of really screwing it up. I also can do things with my numbers now I never could before. It was just a long consultation yesterday, and apparently it got inside my head.

you don’t? :rofl::rofl:

You make it sound so simple. I once had brain surgery… and happened to have NO handle on my diabetes… and was so worried about crashing that I ate pizza, a cheeseburger, some chips, a candy bar—probably some cokes… all before going to sleep. I am so sad to say this is a true story. Not only was I doubled over with abdominal pain the morning of, which sucked all by itself, but my blood sugar was so high they couldn’t do my surgery on schedule. And I had to walk laps in my surgery gown… for like an hour. :rofl::rofl:

I’ve got a pump and sugar tabs now. And I will take all of these reduction suggestions and wade my way through it. And stop with all the drama. :smiley:


Thank you, @bkh. You guys have given me some numbers… I appreciate numbers. :smiley:

1 Like

Just thinking about this… for a surgery of what duration? My doctor thinks it will be at least 2 hours… and that is barring something slowing it down. He also anticipates there’s going to be something that slows it down. So—I have to assume this will be 2-3 hours. Would you still recommend that 0 for an hour prior? I do know I can handle a lot longer suspends while I’m sleeping, so maybe it will turn out fine, but I also think as long as 4 hours (longer if I have to be awake to resume??) could send me sky-bound. What do you think?


Chilidogs and Fire Hot Wings.

Just to give the Surgical Team something to be amused about.



My T1D child recently had surgery. Minor but still with general anesthesia. And as with any surgery always the remote risk of the surgery being extended longer than anticipated.

The Ped Endo team prepared instructions for the Surgical Team.

Immediately prior to surgery we asked the Anesthesiologist Doc if we could keep the Dexcom display. The Doc was completely on board. They were still going to do a fingerstick with the hospital meter every 30 minutes but the Anesthesiologist Doc liked the idea of being able to visually see the Dexcom cgm data in addition to their fingersticks. So we had the iPhone running the Dexcom G6 Mobile App and unlocked so the screen and left the phone on the bed so the surgical team could simply glance at the phone without having to touch it.

EDIT: No BG issues at all during the surgery.


Division of Endocrinology & Diabetes

Day Surgery Recommendations
For Patients on Insulin Pump

Patient Name: MRN:
Expected Date/Type of Procedure:

Please schedule patient for first case

Patient Home Diabetes Management:

Diabetes Regimen: Insulin Pump
Current Insulin Pump: T:Slim with CGM
CGM Type: Dexcom

Long/Intermediate Acting Insulin: Basaglar
Long Acting Insulin Dose for Pump Malfunction: 24 units

Insulin to Carb Ratio: 1: 12am 8 5am 5.5 10:30am 6 10pm 8
Insulin Sensitivity Factor: 1:35 mg/dL
Day: 100 mg/dL, Night: 120 mg/dL
Basal Rates: 12am 0.65 2am 1.0 12pm 0.88 4pm 1.75 6pm 1.81 8pm 1.45 10pm 1.3

Ketone Management: Correction Factor

Pre-operatively – Home Instructions:

Follow pre-operative feeding instructions provided by surgical team
Insulin Recommendations: Recommendations to family for insulin dosing day prior to and morning of surgery (choose one):

Continue usual basal rates and boluses for carbohydrates and correction of high blood sugars up until the time of admission.

Change the battery, infusion set and refill the pump reservoir 8-24 hours before surgery. Infusion set should not be placed near the surgical field.
Bring extra infusion sets, reservoirs, and insulin to the hospital on the day of surgery.

Check blood sugar immediately upon waking up in the morning.
Treat hypoglycemia with clear carb-containing fluid (ex. Apple Juice).
Treat hyperglycemia using usual correction boluses – can give every 3 hours as needed.

Pre-operatively – Hospital Instructions

  • Please note that the following recommendations are with use of aspart insulin (Novolog) – clinically equivalent insulin formulations are lispro (Humalog and Admelog) and glulisine (Apidra)

Blood sugar should be checked by pre-operative staff immediately upon arrival to the hospital or surgical facility.

For hyperglycemia (>240 mg/dl), treat with insulin bolus with pump or subcutaneous injection and check for urine ketones.
Usual correction factor for this patient: 1 unit Novolog* lowers blood sugar by 35mg/dl. Correct to a goal of 150 mg/dl.
If ketones are present (moderate or large urine ketones, or beta hydroxybutyrate level > 1.5 mmol/) contact the diabetes consult service (pager ) for management recommendations.
Consider rescheduling elective procedures in the presence of elevated, persistent ketonuria AND blood glucose > 400.
For hypoglycemia (<80 mg/dl or symptomatic), treat with intravenous dextrose (2-3ml/kg of D10W) and recheck blood sugar in 20 minutes.
Disconnect the insulin pump before MRI scans or at anesthesia/sedation team request. Consider disconnecting the pump for CT scans, interventional radiology procedures, and radiation therapy. Pump can safely be disconnected for 1 hour without giving Novolog. Disconnecting for longer than 2 hours without Novolog will result in hyperglycemia and possibly ketones.

Check blood sugars after inducing anesthesia/sedation and airway is secured. Continue to check blood sugars hourly.
For Hyperglycemia (>240 mg/dl) - Give Novolog insulin every 2 hours as needed – refer to dose recommendation for hyperglycemia (section 2) above.
For hypoglycemia (<80 mg/dl) - Give IV dextrose bolus (2-3ml/kg D10W) and recheck blood sugar in 20 minutes.
Recurrent or refractory hypoglycemia should be treated with additional IV boluses of dextrose or initiation of dextrose infusions (D5W at maintenance rates)

If the insulin pump is accidentally or unexpectedly dislodged or removed, can:
Give subcutaneous injections every 2 hours. Use the correction factor recommendation for hyperglycemia (see section 2) above
Start a continuous Regular insulin infusion – see below section for dosing recommendations for insulin infusion - titrate hourly for goal blood sugars 100-150


Allow child to take fluids/food post-operatively per surgical protocol.
Initiate continuous dextrose containing fluids IV (D5 and 1/2NS at maintenance) if child is unable to meet maintenance oral intake
Once child is able to tolerate PO intake, family may resume home insulin regimen unless otherwise directed by the Diabetes Consult service.
Check blood sugars every 2 hours. May give Novolog insulin correction every 3-4 hours as needed for hyperglycemia according to dose guidelines in section 2 above.
Call Diabetes Consult service (pager# ) for:
Persistent low blood sugars (below 80 mg/dl)
Persistent high blood sugars requiring more than 2 corrections with Novolog as described above
All patients requiring an overnight hospital admission
At time of discharge, advise family to:
Check blood sugar every 2 hours for first 4 hours. After the first 4 hours, family may resume checking blood sugars according to usual routine.
Bolus via pump to correct for high blood sugar readings using usual correction factor.
Bolus via pump to cover all meals and snacks using usual insulin:CHO ratio.
Check for and treat ketones as per usual protocol
Additional instructions: none

For patients requiring an Insulin Infusion (consider for any procedure that is long in duration or may interfere with oral feeding post-op). If an infusion is necessary, please see below recommendations:

Order insulin infusion (Regular Insulin - 0.02 units/kg/hour) from pharmacy the night before surgery. Actual insulin infusion rate will be determined by blood sugar upon arrival in the morning (see below).

Disconnect insulin pump and return device to parents

Begin insulin infusion and D-10 IVF simultaneously within 30 minutes after insulin pump is disconnected.

Initial intravenous insulin infusion recommendations for this patient:

  • 10% Dextrose containing IVF @ maintenance
  • Regular insulin @ 0.02 – 0.05 units/kg/hour:
    Select 0.02 units/kg/hour if blood sugar is 80- 200 mg/dl at beginning of infusion
    Select 0.03 units/kg/hour if blood sugar is 200-300 mg/dl
    Select 0.04 units/kg/hour if blood sugar is 300-400
    Select 0.05 units/kg/hour if blood sugar is > 400 mg/dl at beginning of infusion
    Check blood sugars hourly while on insulin infusion. Titrate infusion (by increments of 0.01 units/kg/hour) and IVF to keep blood glucose levels 80-180 mg/dl.

Dip all urine for ketones (or send for STAT urinalysis). If foley catheter in place, test urine for ketones every 4 hours or every 1-2 hours if blood sugar > 240.

For patients who will be discharged within an hour after the insulin infusion is discontinued:

When patient is ready to come off insulin infusion
1. Patient/Family should prime the pump and confirm basal rates
2. Patient/Family should insert the pump infusion set.
3. Discontinue the insulin infusion and instruct family to reconnect to insulin pump,
resume usual basal rates.
Please note: Patient must reconnect to pump within 10-15 minutes after
insulins infusions has been discontinued.
4. Follow post-operative instructions above

For patients who will remain in the hospital after the insulin infusion is discontinued:
Call Diabetes Consult service (pager# )

Signature of Diabetes Provider:

Pediatric Nurse Practitioner
Division of Endocrinology/Diabetes


Nigerian Prince…I arrived at hospital at 115, and coasted over 3 hours to 95. My gasser pre-surgery had me go to 50% basal 60 minutes prior,based on a bg of 95. I showed him how to operate the pump, alarms, and do temp rates pre-surgery just in case, and never untethered or took my Dex off. The alarms he actually used. Basal/Bolus were handled through IV. I resumed my regime in post-op.


I should not have said it like that. It certainly depends on several things.

The reason I said to do that is because in a fasting state, you may have more of a chance of dropping from normal basal.

If you are above 100 and not showing any signs of dropping, and you have not taken any insulin in the previous several hours, like for corrections or what-not, than an hour of zero basal is definitely overkill.

But what if you were high 2 hours before and you corrected? You might be dropping at the time of surgery. Then it starts to get a bit dicey!

So doing an hour of ZB might be a safety measure. But not a hard and fast rule to do no matter what.

I guess a better answer I should have given you is “it depends”.

Like with running, you know what do to under various circumstances. Sometimes you take insulin and carbs at 70. Sometimes you take carbs at 150. There are no absolutes. It really depends on what your BG is doing that morning.

To be on the safe side, if you have been fasting, have a bit longer ZB than you might if you were eating normally. Make sense?

Also consider, if you are 150, they might slice away on you. If you are 70, they might send you home and tell you to come back another day. Who knows what silliness they will do!

So my recommendation was just overly-cautious. But just apply what makes sense depending on what is happening to your BG that morning. 30 minutes of ZB? 60 minutes of ZB? Right before you start?

The right time to make that call is…the morning of your surgery. Not now.

I have had this same conversation with DM a lot. She asks me what to do with her basal “tomorrow”. And I answer, “I will tell you tomorrow…”


this has always been my experience, too. i have always been the very first one to go under the surgeon’s knive. i wont even bother schedualing a surgery if it is NOT the very first thing in the AM. (but for me, i just wanted to put out there that prepping for a colonoscopie is my idea of a nightmare. SO, that being said, i am going to have the CAT scan version of a colonoscopie rather than the invasive one.)

sorry if i didnt really answer your question.


@T1john, how did everything go?! I can’t believe I didn’t think to ask. :woman_facepalming:


Also interesting.

…okay wow. I don’t know if your endo is just doing what all pediatric endos are doing, or if my endos have never done what all other endos are doing, but I’ve never seen such a comprehensive surgery plan. Down to the time things will happen after the procedure. It’s really impressive. I’ve had huge surgeries since developing diabetes, and every single time my endos fled like inmates on the loose.

I marked the two most interesting parts, but I realized they make sense. It appears they’re not recommending any kind of basal reduction before admission (or to skip correction boluses) which is probably why they can state so definitively that an hour suspend will be fine. I’m not so sure it will be, but without carbs on board, I’m also not sure it won’t.

This is great to read because I’ve always been terrified of doing any boluses at all leading up to a procedure, and this is telling me I can certainly do better than just skipping the dose altogether. That will help me for sure. Thank you, @Thomas, for posting this!


I really like our Ped Endo team.

I do not think they are typical.


Not to good, had over 35 polyps removed (they stopped counting) had cardiac problem during surgery hence the stay. They sent 35 to the lab, 25 were cancerous, 5 HGD, and 5 just polyps. Have 18 serguical clips to close wounds.
Took the test last week, mabey and no signs of spreading. Have been really sick since surgery they are still debating chemo, but put me on high dose sensetick thc for vomiting which helps alot with sleeping, but hungry all the time. Have hard time keeping anything down. Have had probably every test there is at this point, 3 last week alone. One good thing is I have top gastrointestinal doc around.
Enough I really hope all goes great for you, and you got the race Sunday.


Wow, @T1john. I am really sorry to hear it. That’s a lot on top of the a lot you had going on already. I’m glad to hear of your top doctor… it’s hardly enough to cancel out everything else you’ve got going on, but it’s something. You know I wish you the best of luck on all these tests and hope they got everything in time. :confused: