Fasting Not Starving! Dr David Rowe FANZCA VMO Anaesthetist Armidale Rural Referral Hospital Rural SIG meeting Cradle Mountain July 2015

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1 Fasting Not Starving! Dr David Rowe FANZCA VMO Anaesthetist Armidale Rural Referral Hospital Rural SIG meeting Cradle Mountain July 2015

2 Fasting or Starving? Outline Challenge dogma Why do we fast before an Anaesthetic? How long should we fast before and Anaesthetic? Effects of prolonged starvation Preventing Starvation Carbohydrate drinks Fasting in practice in Armidale Updated hospital fasting guideline

3 Challenge Dogma Nil by Mouth from Midnight! Clear Fluids = WATER!

4 Why do we Fast? Prevention of Aspiration of stomach contents Incidence 1 in Mortality 1 in Mendelson labours Solid material - Airway obstruction - Death Liquid Aspiration Cyanosis / Dyspnoea Chemical pneumonitis More Acidic worse injury

5 How do we fast? Rate of emptying depends on what is in the Stomach Solids Fats > Protein > Carbohydrates Generally accepted as 6hrs Liquids Clear Fluids accepted as 2hrs Definition fluid you can read text through Excluded fluids Milky drinks / Carbonated drinks Others Breast Milk infants Accepted as 3-4hrs

6 Challenge Dogma Prolonged fast is a better fast! Acidic Gastric juices constantly secreted Result Larger Gastric Volume More likely to aspirate Lower ph ie More Acidic More toxic Recommendation Encourage clear fluids up to 2-3hrs Pre-Op

7 Effects of Prolonged Starvation Patients Dehydration / Headache Hunger / Thirst Anxiety Physiology Catabolic state Muscle proteins broken down Insulin Resistance

8 Lessons from ICU / Sports Physiology Goal directed therapy O 2 optimisation improves outcomes in ICU Prevention of O 2 debt (lactate accumulation) from anaerobic metabolism VO 2 max athletic anaerobic threshold Exceed > Fatigue / impaired performance

9 Lessons from ICU / Sports Physiology Carbohydrate Loading Several days of CHO s increase Glycogen stores Prolongs time to onset of fatigue in athletes at 75-85% of VO 2 max If we accept parallels between major surgery and major athletic endeavour can sports nutrition principles improve surgical outcomes?

10 Carbohydrate Drinks preop Complex Carbohydrates Malto-dextrins (12%) Handled by the stomach like a Clear Fluid ERAS Enhanced recovery after Surgery 800mls night before 400mls 2-3hrs before Surgery

11 Carbohydrate Drinks ERAS Benefits of CHO Drinks Reduced Dehydration Safe Anaesthesia with empty Stomach Metabolically Fed state Reduced insulin resistance Reduces Catabolism Preserves muscle function grip strength

12 Carbohydrate Drinks Are They Safe? Increased Gastric volume? Meta-analysis clears faster Paracetamol absorbed faster with cup of tea Evidence to support usual administration of medications pre-op. Diabetics? No delay in gastric emptying No increase in hyperglycaemia Take normal oral hypoglycaemic medications with CHO preload

13 Carbohydrate Drinks Conclusions from ERAS 17 elements in ERAS Protocol Only 2 improve outcome independently Oral Pre-Load Reduced intra-operative iv fluids

14 Applying what we know Clear fluids should be encouraged up to 2-3hrs pre-op Smaller / less acidic Gastric Volume Carbohydrate drinks should be given to all patients Regular medications should be given at the normal time e.g. Analgesia best if given regularly Anti-hypertensives Needed for Pts BP to be normal

15 Introducing CHO Drinks to ARRH The Drink preop 200ml bottles from Nutricia How to take it 2 Bottles at Breakfast time, after normal meal last night Bowel Prep 4 Bottles night before Who can give it? Nursing Staff Dietary supplement Does not need to be prescribed

16 Introducing CHO Drinks to ARRH Flowcharts

17 Fasting in Armidale - Study Baseline Group 4 week period (Oct / Nov 2014). Standard fasting information given to patients Am list solid / water Pm list solid / water All patients through OT Questionnaire Time since last Ate / Drank - and details of what. Estimated time since last calorie intake How they felt Hunger / Thirst / Headache / Anxiety

18 Fasting in Armidale - Study preop Drink Group 4 week period (March 2015). Revised fasting information given to patients Am list solid / PreOp Drink Pm list solid / PreOp Drink All patients through OT Questionnaire Time since last Ate / Drank - and details of what. Estimated time since last calorie intake How they felt Hunger / Thirst / Headache / Anxiety

19 Fasting in Armidale Results Demographics 70% 60% 50% 40% 30% Baseline preop 20% 10% 0% Returns Male Female Bowel prep

20 Fasting in Armidale Results preop 115 / 152 = 76% Palatable 94 / 115 = 82% Bad Taste

21 Fasting in Armidale Results Reasons for not consuming 25 No preop 37 /152 = 24%

22 Fasting in Armidale Results Time Since.. (Hrs) Baseline preop Last Ate Last Drank Last Calories

23 Fasting in Armidale Results Incidence of Pre-Op.. (%) 60% 50% 40% 30% 20% 10% 0% Hunger Thirst Headache Anxiety Tiredness Nausea

24 Challenge Dogma Nil by Mouth from Midnight! Clear Fluids = WATER! No More!!