How Strong is the Case for Unrestricted Clear Fluids in Day Cases?

Peter Russell

March 15, 2019

The case for allowing unrestricted consumption of clear fluids for many patients prior to surgery has now been demonstrated in more than 30,000 individuals at a UK hospital, specialists have said.

Guidance on pre-operative fluids fasting policy has continued to evolve, with current European guidelines encouraging intake of fluids up to 2 hours before general anaesthesia. However, theatre delays and cancellations, and patients self-imposing longer fasting times, can often significantly increase this fasting period.

Changing Policy

In October 2014, Torbay Hospital Day Surgery Unit in Devon instituted a policy in which patients were encouraged to drink clear fluids up until transfer to theatre.

A study, first published online in 2017 in the European Journal of Anaesthesiology , examined outcomes for approximately 11,500 day-case patients who received either sedation, general anaesthesia, or regional anaesthesia before and after the policy change.

The data suggested that the liberal consumption of clear fluids before the induction of scheduled day case anaesthesia reduced the rates of postoperative nausea and vomiting.

The study, covering a period between November 2013 and February 2016, represented approximately 78% of all day-case patients before the change in fluids policy and 74% after the change.

Nausea rates within 24 hours of surgery were 3.8% when fluid intake was unrestricted compared with 5.2% when patients did not drink within 2 hours of surgery.

The corresponding rates of vomiting were 2.2% after the unrestricted fluid policy was introduced compared with 2.8% before.

'Continued Success'

The first author of the study, Graham McCracken, a registrar in anaesthesia and intensive care medicine, then working for Torbay and South Devon NHS Foundation Trust, said that subsequent results since the study period had shown continued success for the policy.

He told Medscape UK: "Upwards of 30,000 patients now have gone through that policy, and we know of two cases of pulmonary aspiration of gastric contents during that time, both of which were in patients who had risk factors anyway. They both had a BMI of 35 or over and one of them possibly had a history of reflux."

He added that "we know that the normal rate for patients aspirating is about 1 in 8000 in patients similar to ours, so it's very much in keeping with normal expectancy".

Dr McCracken said the policy change at Torbay reflected an understanding of gastric physiology following research showing that the stomach empties half of its contents approximately every 12 to 15 minutes, and an acknowledgement of the comparatively greater time delay between a patient being called for surgery and the induction of anaesthesia. "It's trying to combine the pragmatic nature of theatre – of sending for patients and transfer – and gastric emptying," he said.

"Certainly, the feedback and the reaction to this paper has been almost completely positive," Dr McCracken said.

Risk is 'Virtually Nil'

An accompanying commentary to the original paper, written by three specialists in anaesthesia from the UK, Norway, and Germany, two of whom contributed to the European Society of Anaesthesiology pre-operative fasting guidelines, pointed out the limitations that not all risk factors for nausea and vomiting had been accounted for in patients included in the study, and that it was not known how many patients in the 'liberal' group had actually drunk clear fluids within the preoperative 2-hour time frame.

However, they said: "The study confirms what we know from case reports and other studies; the risks from a liberal fluid policy are virtually nil and there is no reason to postpone or cancel an otherwise low-risk patient simply because of fluids consumed within the 2-h period."

European Journal of Anaesthesiology: May 2018 - Volume 35 - Issue 5 - p 337–342doi: 10.1097/EJA.0000000000000760 PONV


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