Individual research recommendation details

Recommendation ID

NG180/6

Question

What is the optimal timing of administration of carbohydrate drinks as part of a preoperative fasting strategy?

Any explanatory notes
(if applicable)

Why the committee made the recommendations

Oral fluids

Some evidence showed that drinking water until 2 hours before surgery reduces postoperative headaches, nausea and vomiting. The committee noted that many patients are not aware of this and that there is a widespread belief that fluids should be avoided before surgery. They agreed that there was sufficient evidence to recommend drinking clear fluids before surgery, and that the benefits should be explained to patients.

There was not enough evidence to justify the routine use of preoperative carbohydrate drinks for most types of surgery. A small amount of evidence suggested reductions in postoperative thirst and headache in people given a carbohydrate drink before surgery. However, the evidence did not show any substantial benefits in terms of patient satisfaction or the occurrence of other side effects.

The committee noted that people having major abdominal surgery may need longer postoperative fasting periods and therefore might benefit more than others from preoperative carbohydrate drinks. Some evidence also suggested that length of hospital stay after major abdominal surgery is reduced in people given a preoperative carbohydrate drink. For these reasons, the committee agreed that carbohydrate drinks could be considered for people having this type of surgery.

There was no evidence on the best time to give preoperative carbohydrate drinks or clear fluids so the committee made a recommendation for research on preoperative carbohydrate drinks.

Intravenous fluids

A small amount of evidence suggested a possible reduction in mortality when intravenous crystalloid, rather than colloid, is used for intraoperative fluid management. However, there was also evidence showing that crystalloids resulted in a clinically important increase in nausea and vomiting. The committee were aware that crystalloid use has become more common after reports of increased risks of acute kidney injury, coagulopathy and mortality with colloid. They also noted that crystalloid is less expensive than colloid. They concluded that crystalloid should be considered for intraoperative fluid maintenance.

Cardiac output monitoring

Older evidence suggested that cardiac output monitoring reduces some complications. However, the relevance of this evidence to current practice was unclear because of subsequent improvements in perioperative care such as better preoperative risk assessment and advancements in surgical techniques. More recent evidence also supported the use of cardiac output monitoring to reduce complications, but this evidence was from 1 small study. The committee agreed that cardiac output monitoring should be considered on a case-by-case basis.

Blood glucose control in hospital

There was no evidence that tight blood glucose control in hospital improves outcomes for people with type 2 diabetes or those without diabetes. In addition, there was evidence suggesting that tight blood glucose control increases episodes of hypoglycaemia. The committee therefore concluded that tight blood glucose control is not necessary for people in these 2 groups.

Surgical safety checklists

Evidence showed that using the World Health Organization (WHO) surgical safety checklist (SSC) reduces complications and mortality. Although the SSC is mandatory in NHS practice, the committee were aware from their experience that completion of the checklist varies. They reasoned that the occurrence of preventable 'never events' could be associated with this variation in completion of the SSC. They therefore decided to make a recommendation to highlight the importance of completing the SSC.

In the committee's view, reducing 'never events' should be a primary focus of surgical safety checklists. They agreed that adding steps to the SSC could help to achieve this and should be considered whenever relevant events are reported.

How the recommendations might affect practice

Oral fluids

Current clinical practice on allowing oral fluids before surgery varies, with some services offering carbohydrate drinks before surgery, some allowing clear fluids until 2 to 4 hours before surgery, and others advising people to fast from midnight before surgery. The committee noted that more centres are moving away from traditional preoperative fasting regimens and using the more liberal regimen of clear fluids up to 2 hours before surgery. This recommendation is expected to increase the number of services adopting more liberal regimens.

Intravenous fluids

The use of intravenous crystalloid for intraoperative fluid maintenance reflects current practice and is not expected to result in a change in practice.

Cardiac output monitoring

The recommendation on cardiac output monitoring reflects current practice and is not expected to lead to major changes in practice.

Blood glucose control in hospital

Blood glucose control varies in current practice, although there has been a shift away from tight control because of concerns about hypoglycaemic events. The recommendation is expected to change practice in services that still use tight blood glucose control for people with type 2 diabetes or without diabetes. It may also prevent operations being cancelled unnecessarily on the basis of blood glucose levels.

Surgical safety checklists

The recommendations are expected to reinforce use of the SSC in current practice. Modifying the SSC to address risks highlighted in national patient safety alerts and 'never events' reports is expected to reduce the number of preventable 'never events' that occur.

Source guidance details

Comes from guidance

Perioperative care in adults

Number

NG180

Date issued

August 2020

Other details