Insulin Pumps and Surgery
By M.E.Welch AS, CPhT
Recently I was admitted to a VA Hospital to undergo a vascular procedure that would restore blood flow to my leg. The procedure was needed as I had a shattered heel bone. The Achilles tendon had ripped the bone apart. The feeling of the pain was not dissimilar to being hit by a pro hockey players slap-shot striking the back of my foot. Being a T1 diabetic complicates the process of surgery, especially as I wear an insulin pump and a CGM (Continuous Glucose Monitor). With Insulin Pumps and Surgery, unexpected problems can arise. My surgeon was concerned about hypoglycemia.
The relevancy of this is that my surgeon did not seem to know the first thing about an insulin pump, or how it functioned. The ramifications when it came to Insulin Pumps and Surgery, specifically performing surgery on a patient in this case seemed to perplex him. He spent a good deal of time looking at my pump and seemed quite concerned about its function(s) and how it might complicate the surgery he was about to perform. I am not an Endocrinologist, however; I do know that the pump is essential to my well being. I was also wearing a CGM (Constant Glucose Monitor) that seemed to cause him even more concern.
The physician decided to turn the pump off before surgery which absolutely left my Endocrinologist aghast post surgery. There was no consult between the Surgeon and Endocrinologist before the surgery’s commencement and there obviously should have been. Prior to the surgery; during the pre-op it became well disclosed that I was a type-1 diabetic and reliant on my insulin pump. When is concerns Insulin Pumps and Surgery consults should be mandatory if the surgeon has not been properly trained concerning insulin pumps and CGM’s.
Where did the questions/problems first arise and why?
I have discussed this with my Diabetes Doctor (Endocrinologist) at length and we both came to the agreement that a large part of the confusion leading to problems is a lack of furthering education within the medical professions involved. Not only the Surgeon, but the pre-op personnel such as General Practitioner, Anesthesiologist, Nurses and other staff that a patient passes through before hitting the cutting table. All of these people should raise a flag that the patient is wearing an insulin pump and a CGM monitor. Consultations should become mandatory at that point if the surgeon has any questions or concerns before picking up the scalpel.
If my story causes you alarm it probably should and you would not be alone. Most non-diabetes specialists may have encountered users of insulin pumps but how many know how to handle the situation properly. I fear that some are simply taking their best guess. This may not be good enough and could lead to dire consequences for the patient under their charge.
Things are slowly changing for the better. My Endocrinologist is now planning to go to her department head with this situation and the recommendation that furthering education is not only needed but should be required. I agree.
Furthermore, as in a lot of cases, the US can lag behind when it comes to certain issues including the medical field although the NIH (National Institute for Health) seems to be catching up. It surprises me that the manufacturers of these insulin pumps were not leading the charge for professional education sooner and it is still lacking, even with new graduating physicians.
1st ed. 2019 Edition
This book addresses key principles in the optimal management of diabetes to facilitate smooth and safe anesthesia and surgery with the best possible outcomes. It addresses a range of topics, including: diabetic emergencies, glycemic control in emergencies, the routine perioperative setting, preoperative evaluation in routine and emergency surgery, intra- and post-operative management for neurosurgery, cardiothoracic surgery, gestational diabetes, bariatric surgery and other major surgeries.
Below is an excerpt from The Royal College of Physicians, London, England, UK, ET AL dated June, 2013.
Insulin pumps in hospital: a guide for the generalist physician
Pump therapy entails infusion of short-acting insulin (typically NovoRapid or Humalog) from a reservoir within the pump via plastic tubing into a fine-bore cannula placed in the subcutaneous tissue. The cannula is typically sited on the abdominal wall (although other areas can also be used, and needs to be changed every 3 days. The cannula can be inserted by hand or by utilizing a purpose-designed device. In most models, the needle component of the cannula is removed after insertion, leaving a very fine plastic tube sitting in the subcutaneous tissues. CSII delivers insulin in two patterns: a pre-programmed continuous background insulin infusion (the rate usually varies over the 24-h period), with additional insulin boluses for food or to correct hyperglycemia. People using CSII do not take any additional long-acting insulin: both background and bolus insulin are delivered by the pump. The basal infusion rates are pre-programmed by the patient or his/her diabetes specialist, but can be adjusted by the touch of a button. Basal insulin will continue to run until the insulin cartridge is empty. Insulin boluses are delivered as required under the patient’s direction; most pumpers make use of an inbuilt ‘bolus calculator’, which utilizes known variables for that individual (insulin: carbohydrate ratio, insulin sensitivity and target blood glucose range) in conjunction with situation-specific data (current capillary glucose level, estimated carbohydrate intake and time since last insulin bolus). The pump and tubing can be removed for up to 1 h leaving the cannula in situ, for example for swimming, bathing or contact sports, such as boxing or rugby. Some pumps are waterproof and, therefore, can be kept on for prolonged aquatic pursuits.
What can go wrong and what to do about it?
People using CSII do not take any additional long-acting insulin. Therefore, any interruption to insulin delivery from the pump (eg if the tubing has an air block or the cannula is kinked or dislodged) results in immediate insulin deficiency. Hyperglycemia and DKA can develop quickly, unless the problem is identified and rectified, for example by re-siting the cannula, refilling the insulin reservoir, changing the tubing, or by starting alternative insulin, such as an intravenous infusion. Technical problems with the pumps can occur; the pump manufacturing companies offer round-the-clock telephone support and are typically able to provide a replacement pump within 24 h if required. All patients using pumps are advised to retain a supply of their pre-pump insulin for use in an emergency situation, for example, in case of pump failure or damage.
Pump patients and surgery
There are national guidelines for the peri-operative management of diabetes, but because there are few data on the use of CSII during surgery, recommendations for pump users are based on expert opinion. Fasting is not usually a problem when on CSII; therefore, being ‘nil by mouth’ does not necessarily mean removal of the pump or the need for IV insulin, especially if the starvation period is likely to be short.
Most patients will be able to manage their pump post sedation or post anesthesia as safely as any patient using standard insulin therapy and are more likely to achieve stable glucose control. Hence, it is not necessary to admit day-case patients overnight for VRIII simply because they manage their diabetes by CSII. However, some patients will feel unable to self-manage following the procedure and should discuss this with their diabetes pump team in advance. They might require alternative management, such as prior conversion back to MDI insulin, or hospital admission for IV insulin. For minor procedures (i.e. expected to eat and/or drink within 2–3 h) under general anesthetic or sedation, the pump can remain in situ
. Pre-procedure, the patient should ensure that: their cannula is sited away from the operative site and is accessible to the healthcare team; the pump contains new batteries; the insulin reservoir is full; and capillary glucose is in the acceptable range pre-procedure (ie 4–12 mmol/l). The theatre team must monitor the patient’s capillary glucose levels at least hourly, and start VRIII if any reading is greater than 12 mmol/l. Post procedure, a correction dose might be required, and possibly a temporary increase in basal rates to counteract the stress response to surgery. For any major surgical procedure, where a prolonged period of fasting is expected, CSII should be stopped and replaced by VRIII until the patient is sufficiently recovered and eating again.
As it pertains to Insulin Pumps and Surgery, most patients are safest continuing to use their pump as their form of blood glucose control when admitted to a hospital, unless incapacitated. The increasing use of CSII by patients with T1DM makes it likely that non-diabetologists will have a ‘pump encounter’ in the future. Although this partial review provides the generalist physician with a framework to managing such patients, one should always seek specialist diabetes advice when available. The full review can be found here.
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