Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT05442918 |
| Other study ID # |
StVincentsMelbourne |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
January 15, 2020 |
| Est. completion date |
December 12, 2020 |
Study information
| Verified date |
June 2022 |
| Source |
St Vincent's Hospital Melbourne |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
The investigators propose a multicenter prospective study in patients undergoing either an
elective bariatric procedure or an elective benign procedure, including laparoscopic/open
cholecystectomy, laparoscopic/open hiatus hernia repair, laparoscopic/open inguinal hernia
repair, laparoscopic/open umbilical hernia repair or laparoscopic ventral wall hernia repair.
Perioperative blood ketone and venous blood gas levels will be measured pre-surgery,
post-surgery and on post-operative days until discharge.
Our primary research objective is to clarify the expected perioperative ketone and blood gas
levels in elective bariatric patients who have been on a VLCD and fasting for surgery,
compared to elective surgical patients who have only been fasting prior to surgery.
Description:
Bariatric surgery is fast becoming a mainstream option for achieving long-term weight loss in
the morbidly obese population due to the paucity of other effective alternatives. It is
indicated in those with a Body Mass Index (BMI) >40, or those with an obesity-related
comorbidity with a BMI >35. One of the most common of these comorbidities is Type 2 Diabetes
Mellitus (T2DM).
In the weeks preceding bariatric surgery, it is routine for patients to be placed on a very
low calorie diet (VLCD). The aim is to reduce abdominal wall thickness, visceral adiposity
and hepatomegaly. Overall, this contributes to reduced technical difficulties at operation.
VLCD achieve rapid weight loss in the short term by inducing ketosis. This is achieved by
reducing the consumption of carbohydrate and fat, while increasing protein intake. The
depletion of caloric intake leads to decreased glucose stores. This then leads to a metabolic
shift towards production of ketone bodies, which are produced by the liver via the oxidation
of fatty acids. Ketones are then transported to tissue to take over the role of glucose as
the main energy source for the central nervous system. The objective is to reduce fat mass
without causing excess loss of muscle mass.
Overall the VLCD regime, via the induction of ketosis, is very successful in weight
reduction. However this mechanism of action, and the production of ketone bodies, is now
being questioned in those prescribed a new class of glucose lowering medication used to treat
T2DM.
Sodium-glucose co-transporter-2 (SGLT2) inhibitors, also called gliflozins, are medications
that reduce absorption of glucose in the kidney thus increasing excretion via urine. Phase 3
trials have shown them to be safe for treatment of T2DM however; however concern has been
raised about development of a euglycaemic diabetic ketoacidosis. It is thought to occur when
stress hormones lead to increased ketosis in patients taking SGLT2 inhibitors, which appear
to alter insulin production. This situation can occur in the perioperative period if the
SGLT2 inhibitors have not been correctly withheld pre-operatively.
Current guidelines from the Australian and New Zealand College of Anaesthetists recommend the
cessation of SLGT2 inhibitors 3 days prior to surgery. If this has not occurred, they state
blood ketones should be tested. If the blood ketones are >0.6, it is a strong recommendation
to postpone non-urgent surgery. Ketone and base excess levels are then used to monitor
patients in the perioperative period.
The confounding factor in these patients now presents itself- what are the expected blood
ketone levels in bariatric patients who have been on two week of pre-operative VLCD and are
fasting for surgery?
