The document discusses preoperative metabolic conditioning and fasting guidelines. It summarizes several studies that show: 1) Clear fluids can be consumed up to 2 hours before surgery and solid foods up to 6 hours with no increased risk of complications. 2) Preoperative carbohydrate loading improves postoperative insulin sensitivity, muscle mass, and cardiac and organ function compared to fasting. 3) Preoperative nutritional support is recommended for patients with severe pre-existing nutritional risk or those requiring prolonged postoperative fasting.

1. Preoperative metabolic conditioning J.-Philipp Breuer Departments of Anaesthesiology and Intensive Care Medicine Campus Charité Mitte und Campus Virchow-Klinikum CHARITÉ – Universitätsmedizin Berlin

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3. ± 49 min ± 30 min 5 h 8 min 3 h 8 min 4 h 30 min 4 h 30 min to 20 h 15 h 12 h 30 min 14 h 20 min 12 h 28 min Solids Fluids 95 % CI SD Range Median Mean 2 Number of cases 6 4 2 0 8 10 12 1 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Fasting (h) Preoperative Fasting (n = 153) Pearse et al Eur J Anesthesiol 1999 Preoperative metabolic conditioning

4. Early morning  postabsorptive status  Liver glykogen   Proteolysis/lipolysis  C ontrolled catabolism Operation  stress metabolism  Stress hormones  , cytokines   Hypercatabolism Substrat supply  insulin   Glykogen synthesis & peripheral glucose up-take   Anabolism Hunger metabolism & Operation Breuer et al Akt Ernähr Med 2006 Preoperative metabolic conditioning

5. Perioperative Nutrition Metabolic impact Hyperglycemia Morbidity, Mortality Protein breakdown Depletion Rehabilitation – Length of stay Insulin resistance Intracellular energy sources Oxidative stress Organ function Intestinal barriers Bacterial translocation Insufficient nutritional status + Surgical trauma Breuer et al Akt Ernaehr Med 2006 Preoperative metabolic conditioning

6. Cochrane-Analysis 38 randomized controlled comparisons (22 trials) Objects: perioperative complications & comfort “ […] no evidence to suggest a shortened fluid fast results in an increased risk of aspiration or related morbidity […].” Level of Evidence = 1a “ […] appraise this evidence for themselves and […] adjust any remaining standard fasting policies for patients that are not considered `at risk´ during anaesthesia.” Grade of Recommendation = A Brady et al The Cochrane Collaboration 2003 Preoperative metabolic conditioning

7. Clear fluids up to 2 hours before induction of anesthesia Solid food (small meal or milk) up to 6 hours before anesthesia Stellungnahme der DGAI und des BDA. Anaesth Intensivmed 2004 Spies, Breuer et al Anaesthesist 2003 Preoperative metabolic conditioning Update on preoperative fasting

8. Clear fluids shortly before surgery - Discomfort & Outcome - Thirst / Hunger  Anxiety  Postoperative pain  PONV  Dehydration  Postoperative delirium  Brady et al The Cochrane Database 2003 Castillo-Zamora et al Paediatr Anaesth 2005 Maharaj et al Anesth Analg 2005 Hausel et al B J Surg 2006 Radke et al Anaesth Intensivmed 2007 Preoperative metabolic conditioning

9. Preoperative Metabolic Conditioning Feeding vs Fasting before Stress stimmulus Stress hormons  Hemostasis  Intenstinal barrier function  Bacterial translocation  M uscle function  Cardiac performance  Bouritius JPEN 2008 Ljungqvist et al Circ Shock 1987 Eshaili et al Eur J Surg 1991 Ljungqvist et al Can J Physiol Pharm 1986 Friberg et al Surg Res Comm 1994 Bark et al Eur J Surg 1995 Aligobevic et al Circ Shock 1993 Nettelbladt et al Nutrtion 1996 Van Hoorn Nutrition 2005 Preoperative metabolic conditioning

10. E nhanced R ecovery A fter S urgery (ERAS) / Fast-Track-Chirurgie Kehlet et al Am J Surg 2002 Preoperative metabolic conditioning Schwenk et al Int J Colorectal Dis 2008 Preoperative fasting  CHO Load POD 0 from 2. postoperative hour  tea, protein drinks/ yoghurt POD 1 regular food + protein drinks POD 2 regular food + 1,5L fluids to drink

11. Postoperative Insulin Resistance Thorell et al. Curr Opin Clin Nutr Metab Care 1999 p < 0.001, ANOVA n = 6-13 Insulin sensitiviy (%) Lapar. Cholecyst- ectomy Hernio- tomy Chole- cyst- ectomy Colo- rectal- surgery Preoperative metabolic conditioning 0 20 40 60 80 100

12. Change in insulin sensitivity (%) 0 -10 -20 -30 -40 -50 -60 Glc i.v. Control p < 0.01 0 -10 -20 -30 -40 -50 -60 Placebo p < 0.05 Verum Ljungqvist et al J Am Coll Surg 1994 Soop et al Am J Physiol Endokrinol Metab 2001 Glucose i.v. before cholecystectomy Glucose oral before hip replacement n = 15 n = 12 Preoperative metabolic conditioning

13. Preoperative carbohydrates & Skeletal muscle mass Double blind, randomised, placebo-controlled Yuill et al Clin Nutr 2005 TSF = triceps skinfold thickness, AMC = mid-arm muscle circumference (CHOD = 12.6g CHOD/100mL) Evening before surgery: 800mL (Placebo/CHOD) Morning 2 hours before surgery: 400mL (Placebo/CHOD) N = 65 Preoperative metabolic conditioning p=0.05

14. Preoperative Carbohydrates & Skeletal muscle mass randomised, controlled Noblet et al Colorec Dis 2006 n = 12, CHOD (100g/800mL evening + 50g/400mL 3h preop) n = 11, Water (800mL evening+ 400mL 3h preop) n = 12, Fasting (NPO after midnight) Preoperative metabolic conditioning 10 5.7 13 p=0.01 p=0.06 -11% p=0.05 -8% p=0.7 -5% p=0.6

15. Carbohydrates before cardiac surgery Double blind, randomised, placebo-controlled Breuer et al Anesth Analg 2006 Preoperative metabolic conditioning

16. van Hoorn et al Nutrition 2005 Preoperative metabolic conditioning

17. Cardiac function van Hoorn et al Nutrition 2005 Preoperative metabolic conditioning

18. Energy status lung van Hoorn et al Nutrition 2005 liver intestine Preoperative metabolic conditioning Oxidative stress

19. Ischemia/Reperfusion model Randomization sham fasted I/R fasted I/R CHOD Parameters of organ dysfunction Kreatinin, Urea Asymmetrical dimethylarginine (ADMA) Interleukin (IL)-6 van Hoorn Clin Nutr 2005 Preoperative metabolic conditioning

20. Renal function van hoorn Clin Nutr 2005 Liver glycogen Sham I/R CHOD I/R fasted Sham I/R CHOD I/R fasted Preoperative metabolic conditioning

21. van hoorn Clin Nutr 2005 ADMA IL-6 Sham I/R CHOD I/R fasted Sham I/R CHOD I/R fasted Preoperative metabolic conditioning

22. „ From the metabolic and nutritional point of view, the key aspects of perioperative care include: avoidance of long periods of pre-operative fasting; re-establishment of oral feeding as early as possible after surgery; integration of nutrition into the overall management of the patient; […]“ Weimann et al Clin Nutr 2006

23. ESPEN – Guidelines Enteral Nutrition 2006 ( oral nutritional supplements & tube feeding) A = ≥ one randomised study, B = non-randomised study, C = clinical experience, experts´ opinion Weimann et al Clin Nutr 2006 Indications – perioperative Patients with severe nutritional risk prior to major surgery  nutritional support for 10 to 14 days ( A ) Weight loss 10-15% within 6 months BMI < 18,5 kg / m 2 Subjective Global Assessment Grad C Serum Albumin < 30 g / l Initiate nutritional support … even in patients without obvious undernutrition, if it is anticipated that the patient will be unable to eat for more than 7 days perioperatively ( C ) in patients who cannot maintain oral intake above 60% of recommended intake for more than 10 days ( C ) Preoperative physical and metabolic conditioning 21st ESICM Annual Congress Lisbon 2008

24. Preoperative Immunonutrition 13 RCTs / gastrointestinal cancer n=1269 not significant postoperative mortality OR = 0.91 (p= 0.84) significant postoperative infection rate OR =0.41 (p<0.00001) length of hospital stay WMD=-3.48 (p<0.00001) Zheng et al Asia Pac J Clin Nutr 2007

25. Prehabilitation in Elderly Patients abdominal or cardiac surgery: n= 275 elderly patients fewer postoperative complications shorter postoperative length of stay improved quality of life reduced declines in functional disability orthopaedic surgery: quality of life or recovery not improved Carli et al Curr Opin Clin Nutr Metab Care 2005

26. Conclusions Preoperative fasting from midnight is unnecessary in most patients  clear fluids up to 2h and solids up to 6h before surgery Prior to major surgery  Recommendation of CHO-Loading Patients with severe nutritional risk prior to major surgery  preoperative nutritional intervention plus delay of operation Prehabilitation prior to surgery  in abdominal and cardiac surgery recommended

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