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Nutritional Care of the Bariatric Patient in Critical Care Christine Ward Bariatric Dietitian September 2011. Aim . To identify factors that may impact on the nutritional care of the bariatric patient group Why this group may require a Critical Care admission?
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Nutritional Care of the Bariatric Patient in Critical CareChristine WardBariatric DietitianSeptember 2011
Aim • To identify factors that may impact on the nutritional care of the bariatric patient group • Why this group may require a Critical Care admission? • What are the potential issues regarding feeding? • Which BMR estimation equation is most appropriate for the bariatric patient?
Factors that may impact on nutritional care of bariatric patients • Obese patients generally viewed as over nourished • Potentially deficient in a number of nutrients • Respond to injury differently; can not utilise/mobilise fat stores for energy as well as lean counterparts • Will draw on lean mass for energy • Considered that they may already metabolically stressed due to obesity • 2 weeks Pre-operative dietary restriction ~1000kcal/day
Type of Surgery Laparoscopic Procedures • Restrictive • Adjustable Gastric Band • Sleeve Gastrectomy • Restrictive and Malabsorptive • Roux-en-Y-Gastric Bypass • Duodenal Switch /BPD
Critical care admission? • Planned Critical Care • Clotting issues thrombolysis • CPAP: patient not independent
Unplanned Bariatric patients in Critical Care • Undiagnosed sleep apnoea • Prolonged ventilation • Large bleeds - liver • Conversion to open procedure • Rhabdomyolysis, renal failure, sepsis, respiratory failure • Anastomotic leak or stricture ERI: 5% patients (6-20% cited in many papers)
Feeding Route? • Usual Protocol post surgery • Oral Route • Immediately post bariatric surgery if gut intact • day 1; sips, • day 2; clear fluid, • day 3; free fluid • Use of nutritional supplements, high protein where appropriate
Enteral or Parenteral Nutrition • ? NG, NJ , gastrostomy / jejunostomy • Altered gastrointestinal anatomy/function • Which feed? • TPN • How soon? • ?Within 48 hours or ? NICE 2006 • Re-feeding issues K, Mg, PO, thiamin • Biochemistry monitoring (daily or as local protocol) • Is it possible to meet nutritional requirements? • Overfeeding vs. under feeding
Risks from nutritional support for the obese patient • Overfeeding • Increase C02 , breathing and prolonged mechanical ventilation • Promotes fat infiltration of liver (esp. CHO) • Cautious administration of CHO (dextrose) fat and fluid for obese with T2DM, Congestive heart failure, metabolic syndrome (exacerbation of conditions)
Hypo energetic feeding and protein sparing • Improved glucose control • Improved serum iron binding and albumin • Appropriate energy deficit without increasing lean tissue catabolism can be achieved • Dickerson et al 2004, Choban et al 2005, 1997 50% of energy requirements and 2.1g protein /kg IBW resulted in N balance
Aim of nutritional support in critically ill patients? • Meeting measured energy requirements vs. preservation of lean body mass vs. risks of under or overfeeding
BMR Prediction Equations (Schofield) • Criticism of current PENG guidance • Estimations equations based on healthy population • Inappropriate use of stress factors; overestimates • Use of static variable such as weight, the body’s physiology ?temperature and respiration rate • Based on a linear relationship between weight and BMR
However • Findings from Horgan and Stubs 2003 re-examination of Schofield equation: • Small numbers of obese patients • BMI>30 =4.5% • The linear relationship between BMR, weight, height and age only evident to a weight of ~ 70-75kg
BMR Prediction Equations • Over estimates requirements for high BMI • Adipose tissue to lean tissue relationship 75:25 • Main determinant of BMR is lean tissue • Obese have a higher absolute BMR due to a greater total mass of metabolically active tissue • BMR /Kg is lower due to the higher proportion of adipose tissue • BMR/Kg of fat free mass for most subjects is the same
Henry/Oxford Equations 2005 • Based on studies from 1914-2005 • 10,552 BMR values • Rigorous evaluation of methodology • Advantages • Contains a more representative sample of the world population
SACN recommendations (draft)(www.sacn.gov.uk) • Use of Henry BMR equations • Weight only • Height and weight • Henry found no significant advantage in ht & wt equation • For predicting BMR using weight only • (height difficult to obtain in clinical setting) • Launch later this year
Assessment prior to feeding • As you would for other obese or lean individual • Up to date weight crucial • Scales suitable for purpose, bed, hoist, stand on, • Immediately pre-surgical for bariatric patients available • Reported weight or estimated • Knowledge of patient background, • type of surgery, • nutritional intake prior to surgery, • amount of weight loss/time • Potential for nutritional deficiencies
Calculating nutritional requirements? Energy requirements Non stressed • Feed to BMR using actual body weight with -400-1000kcal for decrease in energy stores Mild to moderate stress: • Calculate as normal • Omit stress and activity avoiding adverse effects of overfeeding Severe stress • Might be necessary to add a stress factor to BMR
Obesity Double Check In order of decreasing accuracy / evidence • Ireton Jones energy equations (critically ill but not ventilated) • Adjusted average weight (PENG pocket guide4) • 19-21 kcal/kg actual body weight (critically ill only) Glynn 1999, Alberda 2002
Protein Requirements4 • 0.2g N/kg Actual body weight x 6.25 • And where • BMI >30 use 75% of the value estimated from actual weight • BMI> 50 use 65% of the value estimated from actual weight
Fluid Requirements4 • Very individual; ventilation, • The guidelines err on side of caution • Fluid requirements not a linear relationship with weight, • Avoid fluid overload • Consider, is volume sensible? 2000-3000mls • Have losses been taken into account
Final thoughts • Estimated Energy requirements only starting point • Review and monitor patient regularly • Consider duration of nutritional support? • Are nutritional goals being met? • Requirements change: patients clinical condition, nutritional status, stress level, prognosis • Never blindly follow guidelines: clinical judgement required
References • American Society for Metabolic and Bariatric Surgery Guidelines 2008 • Ernst B, Thurnheer M, Schmid S M, Schultes B. Evidence for the necessity to systematically assess micronutrient status prior to bariatric surgery. Obesity Surgery. 2009; 19:66-73 • Flancbaum L, Belsley S, Drake V, et al. Preoperative nutritional status of patients undergoing Roux-en-Y gastric bypass for morbid obesity. J Gastrointest Surg. 2006;10(7):1033-7 • A Pocket Guide to Clinical Nutrition. 3rd Edition. The Parenteral and Enteral Nutrition Group of the British Dietetic Association. 2007 • Cheatham ML, Safcsak K, Brezinski SJ, et al Nitrogen balance, protein loss and open abdomen. Crit Care Med. 2007;35:127-131