Diving by diabetic patients using a subcutaneous insulin pump
Dear colleagues,
I am involved in writing a Dutch guideline for diving by patients with diabetes. We are of course using the 2005 DAN/UHMS "Diabetes and recreational diving" workshop proceedings as a basis.
One specific issue we are struggling with is what the best advice may be for divers with diabetes that use a subcutanous insulin pump.
Of course, these pumps must be disconnected prior to diving. There are then two options:
1) leave the patients without insulin during the dive and to re-attach the pump after the dive. The risk is that if this takes too long, the type I diabetic patient may become ketotic of even ketoacidotic. Allthough this will take several hours to develop and the diver will generally be back on the insulin by then, is this a safe option?
2) switch the patient to a classic combination of long-acting insulin with bolusinjections of short-acting insulin for the day. This allows for a tailored basal dose of insulin during the dive and thereby prevents keto(acido)sis. However, making such a drastic switch in insulin-treatment carries the risk of inappropriate dosing.
Do any of you have experience with such patients?
Best regards,
Peter
My pump is an Animas 2020 which can be disconnected for up to an hour. It is okay to disconnect the pump when at the gym or swimming so I presume it is fine to disconnect the pump for diving as long as the dive is for less than an hour. After the dive the pump is then re-connected with no adverse effects on the patient.
Can't say I have any experience of diving and insulin pumps. The problem is that diving can be associated with signficant drops in BSL - possibly relating to the increased inspired oxygen pressure as this is a well-recognised complication of hyperbaric oxygen treatment.
The key to successful manangement is allowing the BSL to rise prior to diving and then disconnecting for a short period (up to an hour sounds good to me). The sugar needs to be estimated several times and appropriate action taken during a diving day.
The SPUMS has a recently published guideline on diving for those with insulin dependent diabetes and a careful plan would have to be approved by both diabetologist and the diving doctor based on the guideline.
The biggest hurdle may be the lack of appropriately trained and resourced dive instructors and training agencies. I am not aware of an official training setup in NSW aimed at qualifying novice divers who use inslulin. Would love to know if one exists!
I am happy to try and assist in getting people with diabetes what they need to succesfully dive, but it will not be straighforward.
Mike
Thank you for your responses, Jenny and Mike !
Jenny: I think it is a valuable suggestion to take experiences from other sports into account when deciding on this issue. In fact, I think it is imperative that a diver with type I diabetes is experienced in regulating his/her blood suger in relation to exercise above water before even considering doing so under water.
I absolutely agree with Mike, and this is also included in the UHMS consensus document from 2005, that blood suger glucose trends rather than just single pre-dive values are key in understanding what is going to happen during the dive. When a pump is involved, this principle is of course heavily affected by the sudden stop in insuline administration when it is disconnected. Disconnecting the pump prior to the dive will generally cause a rise in blood sugar, but exercise and factors such as increased pO2, will lead to decreases in blood glucose. It is clear that a diver needs to start with low-intensity, short dives and expand on this experience step-by-step whilst carefully documenting the experience in the log book (glucose trends, carbohydrate intake, pre/postdive values). Published experiences with type I diabetic novice divers (Pollock et al. UHM 2006, vol 33, No 2) show rapid learning curves and predominantyl hyperglycemia btw. These series did not include divers using a subcutaneous pumps though.
Mike- when you refer to the SPUMS guideline, do you mean the 'suggested assessment for the diver with diabetes' published in Diving and Hyperbaric Medicine in the september issue of 2010?
I think we all agree that disconnecting a pump for an hour or so should be safe. I've also understood from Chris Edge in the UK that he also advises divers to disconnect the pump rather than shifting to a long-acting insuling. I'm still wondering how much margin there is in the maximal acceptable timeframe as doing one hour of diving means a substantially longer period of disconnecting the pump. Disconnecting the pump will need to be done prior to donning the wetsuit and the diver needs to be on deck, out of the wetsuit and with all materials at hand to reconnect it. And what if the diver makes a mistake navigating and needs soms additional surface time to return to the exit point?
I suppose it is a matter of individual learning curves and tailored choices. For now, my conclusion is that disconnecting the pump without a switch to long-acting insulin is the general advice.
Thank you all again.
Peter
One of my registrars had an insulin pump. We disconnected it prior to her doing a chamber dive and monitored her BSL pre during and post the pressurization. She tended to drop he BSL as we see in our patients. I think that this would be the best idea.
Denise