Does starvation before the surgery result in hypoglycaemia during surgery, or are children without diabetes able to regulate their perioperative blood sugars effectively?

July 12, 2010

July 12, 2010

Kathryn Jones and Ralph Mackinnon, Medical Student and Consultant Paediatric Anaesthetist respectively (Royal Manchester Children's Hospital)

In [children] is [prolonged preoperative fasting] associated with [perioperative/postoperative hypoglycaemia]?

A child requires a surgical procedure and therefore must be kept nil-by-mouth for several hours prior to the operation. This precaution reduces the volume and acidity of gastric contents, thereby reducing the risk of aspiration. Although surgery may increase blood glucose via a systemic stress response, the period of pre-operative starvation may cause children to become profoundly hypoglycaemic(as they are less able to regulate their blood sugars effectively than adults). This problem is contributed to by the fact that the fasting period is often longer than planned because of bigger surgical lists or poor planning. Are current fasting practices getting the correct balance between prevention of complications and safe blod sugars?

MEDLINE 1950 – June week 1 2010
EMBASE 1980 to 2010 Week 23
CINAHL 1982 to June week 1 2010
Using the OVID interface.

((exp Preoperative Period/ or exp Preoperative Care/ or preoperative.mp.) OR (exp Anesthesia, General/ or exp Anesthesia/ or Anesthesia, Intravenous/ or an*esthesia.mp. or exp Anesthesia, Inhalation/) OR (an*esth$.mp.)) AND (Fasting.mp. or exp Fasting/) AND ((exp Hypoglycemia/) OR (hypoglyc$.mp.)) (limit 9 to (english language and humans and ("newborn infant (birth to 1 month)" or "infant (1 to 23 months)" or "preschool child (2 to 5 years)" or "child (6 to 12 years)" or "adolescent (13 to 18 years)"))

MEDLINE found 45 results, of which 23 were relevant and of sufficient quality to be included. Three of these papers were review articles and as such not suitable for full critical appraisal but will be discussed in a later section.
One of the papers could not be obtained using the John Rylands University Library’s Inter-library loans service, and could therefore not be appraised.
EMBASE and CINAHL found no further papers.
Searching of the references and hand searching found 3 more relevant papers.

Being hypoglycaemic is problematic during surgery as it can affect the way in which a child behaves physiologically, both when under anaesthetic and when regaining consciousness afterwards. It is therefore important to prevent this occuring, whilst balancing this with the prevention of aspiration pneumonitis.
The findings of the papers studied are extremely variable. Some of the older papers (Thomas et al, Watson et al, Bevan et al and Allison et al) found worryingly high occurance of severe hypoglycaemia. Several of the papers found that hypoglycaemia was affecting a smaller but significant minority of children (Shah et al, O'flynn et al, Welborn et al and Jensen et al).
Despite variation in definitions of hypoglycaemia and results, there is a common trend running throughout many of the papers. This is that the youngest, and therefore smallest, children are less able to regulate their blood sugars effectively following a period of starvation. This was the case in many of the papers studied, as demonstrated by Payne et al (16), who found that 36% of those children over 1 year but under the 3rd centile for weight were hypoglycaemic when anaesthetic was induced, and found hypoglycaemia at some point during the anaesthetic (BM< 3mmol/L) in 11% overall.
However, several of the papers read demonstrated that the children studied were able to readily regulate their blood sugars without becoming hypoglycaemic (Somboonviboon et al, Van der Walt et al, Shah et al, Aun et al, Nilsson et al and Srinivasan at al).
All papers that measured blood glucose postoperatively confirmed the expected hypothesis that blood glucose would increase after surgery due to a physiological stress response. One or two children did not fit this pattern, but many of these were hypoglycaemic before surgery and may have behaved differently because of this.
Many of the papers studied were several decades old and only obtained data from a small cohort; therefore perhaps more detailed research into the area is required in the form of large randomised control trials comparing starved children to those allowed a source of glucose pre-operatively. Further evidence may add weight to one side of the argument and enable clinicians to decide on a definite ‘safe’ fasting time, or on whether to provide pre-operative glucose.

It is difficult to draw a definite conclusion on the issue with such varied results; however the research and this paper have highlighted the issue as an important one which must be considered further due to the potentially disastrous consequences of prolonged hypoglycaemia. Many of the papers suggest that children are able to regulate their blood sugar without food, as long as fasting is not protracted. An important trend in many papers is that younger or lighter children are the ones becoming hypoglycaemic, perhaps indicating that specific care must be taken when considering the length of pre-operative fast in this group of patients. Almost all of the papers showed that children remained asymptomatic despite having low blood sugars, perhaps suggesting that much hypoglycaemia goes undetected in clinical practice where blood sugars are not measured as routine at induction of anaesthetic.

1. Murat. I et al. Perioperative Fluid Therapy in Pediatrics
2. Gupta. P et al. Preoperative Fasting and Plasma Glucose levels in Children
3. Bush. G et al. Severe hypoglycaemia associated with preoperative fasting and intraoperative propranolol. A case report and discussion
4. Somboonviboon. W et al. Blood Glucose Concentration in Pediatric Outpatient Surgery
5. Somboonviboon. W et al. Blood Glucose Concentration in Pediatric Outpatient Surgery
6. Phillips. S et al. Preoperative fasting for paediatric anaesthesia- Review Article
7. Aun. C et al. Preoperative Fasting in Children- Review Article
8. Huang SJ et al. Prolonged fasting in pediatric outpatients does not cause hypoglycemia
9. Amponsah. G et al. Blood sugar concentrations in children undergoing surgery under general anaesthesia
10. Shah. M et al. The effect of Pre-anaesthetic fasting on blood glucose level in children undergoing surgery
11. Shah. M et al. The effect of Pre-anaesthetic fasting on blood glucose level in children undergoing surgery
12. Aun. C et al. Paediatric glucose homeostasis during anaesthesia
13. Long. T et al. An unusual case of symptomatic hypoglycaemia in a child
14. O'Flynn. P et al. Fasting in children for day case surgery
15. Van der Walt et al. A Study of Preoperative Fasting in Infants Aged Less Than Three Months
16. Welborn. L et al. Perioperative blood glucose concentrations in pediatric outpatients
17. Van der walt. J et al. The effect of different Pre-operative feeding regimens on plasma glucose and gastric volume and pH in Infancy
18. Redfern. N et al. Blood Glucose in anaesthetised children
19. Payne et al. Plasma glucose levels in the peri-operative period in children
20. Srinivasan. G et al. Glucose homeostasis during Anaesthesia and Surgery in Infants
21. Nilsson. K et al. Blood-Glucose Concentrations During anaesthesia in Children
22. Jensen et al. Preoperative starvation and blood glucose concentrations in children undergoing inpatient and outpatient anaesthesia
23. Allison et al. Pre-operative starvation in children -The role of alanine in blood glucose homeostasis
24. Bevan et al. Acid base changes and Anaesthesia-The influence of pre-operative starvation and feeding in paediatric surgical patients
25. Ffoulkes. D et al. Effect of anaesthesia and surgery on blood sugar and carbohydrate tolerance in African Children
26. Ware et al. Postoperative Hypoglycaemia in small children
27. Thomas et al. Hypoglycaemia in Children before operation: Its incidence and prevention
28. Watson et al. Blood glucose levels in children during surgery