Perfusion & Morbid Obesity…

2. Perfusion & Morbid Obesity… ….as it relates to HYPER-PERFUSION of the obese patient.

3. OBJECTIVES .....to provide you with a method of calculating a realistic Body Surface Area (BSA) for the Obese population. I’ll do this by showing you current and acceptable data regarding BSA calculations using Ideal Body Weight as based on Body Mass Index (BMI) versus using the patients current obese body weight. .....to get you to rethink how you make you perfusion flow calculations and the need to make your calculations at a BMI of 27, for any obese patient with a BMI over 27, regardless of gender or age. A BMI of 27 is closer to an Ideal Body Weight.

5. In 1943, Metropolitan Life Insurance Company used a Height and Weight Table for their underwriters to use when they wrote an insurance policy

6. …..in 1983 the table was revised and published as seen here

8. Do you fit their “Ideal Profile” ? • Find your height • Using their body type category find your max weight • How many here fit the profile? • I never weighed 197 even when assigned to the Second Marines!

12. Using the graphic from the back of the clip board: a patient height of 6 foot and 2 inches and a weight of 260 pounds, their BSA would be….

14. Is that 2.44 ? …..the point is that the outcome is dependent on the start and end point and the thickness of the line drawn, not to mention the accuracy of the height and weight. Fortunately for our patients we now have the math and programs that do the calculation once we enter the height and weight.

15. Body Mass Index • In the middle 1800’s Adolphe Quetelet, a Belgian mathematician, invented this index. Quetelet’smath was used to show the probability of normal distribution of heights of French conscripts and the chest circumference of Scottish soldiers. • Lost in history his math emerged in “useful” medical math calculations in 1970 and is now used to grade levels of “obesity” • Became internationally popular in the 1980’s • June 1998 – National Institutes of Health (NIH) gave approval for the current BMI standards • What is Body Mass Index (BMI) ?

16. Body Mass Index, better know as BMI, is a number or INDEX, that relates a persons weight to their height. The calculation in metric measurements is weight in kilograms(Kg) divided by height in meters squared. Using previous weight and height of 6’ 2” & 260 lbs. 6’ 2” = 188 cm 260 lbs. = 118.2 kg 118.2 / (1.88)squared = 118.2 / 3.53 = 33.5

17. Obesity N.I.H and the World Health Organization have defined Obesity: “Obesity is defined as a Body Mass Index (BMI) over 30.

18. The National Institutes of Health now defines under weight, normal weight, overweight and obesity according to BMI. Overweight is a BMI of 25 – 29.9 Obese is a BMI of 30 or more

23. W.H.O. Obesity and overweight Updated March 2013 • Worldwide obesity has nearly doubled since 1980. • In 2008, more than 1.4 billion adults, 20 and older, were overweight. Of these over 200 million men and nearly 300 million women were obese. • 35% of adults aged 20 and over were overweight in 2008, and 11% were obese. • 65% of the world's population live in countries where overweight and obesity kills more people than underweight. • More than 40 million children under the age of five were overweight in 2011. • Obesity is preventable !!

26. In this issue of Health & Wellness: • Talks about how BMI does not address muscle massand that most professional athletes would be considered obese as indicated by their BMI. • Talks about BMI and that it is not an indicator of overall health, having a normal BMI does not equate to being healthy. • That using BMI to classify a persons weight must take into account their body composition and/or body type • Asks who or what is to “BLAME” for the Obesity Epidemic? • Gives some keys to weight loss • Talks about Bariatric medicine.

27. Remember the Met Life Chart from 1983? It seems that the growing obesity issue has brought about an adjustment in that table:

28. 1983 Met Life Chart

29. New “Obese” Met Life Chart

30. Side by Side of Met Life “OLD 1983” 6’2” – 260 lbs. “NEW” 6’2” – 260 lbs. (Weight for Small, Medium and Large Frames) (MINimum weight, max weight for preferred, Max weight for MOST conditions, and Max weight for Consideration)

33. What is the point ? The point is: we have been dealing with an obese population for some time and those of us who use a BSA calculation that is based on the obese patients current weight have more than likely been hyper-perfusing that patient. The point is:the obese population is not getting thinner and more than likely will be getting less healthy, over time. The point is:depending on the overall health condition of the obese population (smoker, black lung, COPD, or any pulmonary system compromise) over perfusion can cause a “wet lung” situation. Do we “OVER PERFUSE ? Let’s revisit the patient we referenced earlier. He was 6’ 2” and 260 lbs.

34. 6 foot 2 inch & 260 pounds Current Weight of 118.2 kg Using 95kg, weight for a BMI of 27 188cm & 118.2kg = BSA 2.44 • 1.8 = 4.4 • 2.0 = 4.9 • 2.2 = 5.4 • 2.4 = 5.9 • 3.0 = 7.3 188cm & 95kg = BSA 2.22 • 1.8 = 3.9 • 2.0 = 4.4 • 2.2 = 4.8 • 2.4 = 5.3 • 3.0 = 6.6

35. FLOW comparison of CW vs BMI of 27 This patient is an old 2 ppd smoker who stopped smoking 17 years ago. • 1.8 - 4.4 vs 3.9 a difference of 500 ml of flow • 2.0 - 4.9 vs 4.4 a difference of 500 ml of flow • 2.2 - 5.4 vs 4.8 a difference of 600 ml of flow • 2.4 - 5.9 vs 5.3 a difference of 600 ml of flow • 3.0 - 7.3 vs 6.6 a difference of 700 ml of flow

36. Is this patient going to be over perfused? • Is the BSA for current weight going to be used? • Is the higher perfusion flow and compromised pulmonary bed going to cause third spacing? • Is the loss of circulating volume going to lead to added crystalloid and potentially more third spacing? • Will this patient need blood post pump because of volume shifts? • Will this patient spend and extra 12 to 24 hours on the ventilator due to pulmonary issues related to pump lung?

37. NO ! • Because this patient was me 10 years ago and I asked my perfusionist to pump my ideal weight at BMI 27. • Because I asked my perfusionist to use serial venous blood gases to guide his flows. • Because he was able to flow at a lower level, he didn’t drive third spacing. • Because the third spacing was minimal in the pulmonary bed and pump lung did not occur.

38. Let’s look at some examples of obese patients and the potentials for hyper-perfusion:

39. Flow differences in the “Obese” & “Very Obese” Current2.4 @ Weight BMI of 27 BMI SEXHeightkg BSAWeightBSACW27Difference F 5’ 5”96.82.0372.7 1.804.874.32550 ml M 6’ 1” 126.42.4893.2 2.185.955.23720 ml M 5’ 9” 114.12.2884.1 2.005.474.8670 ml F 4’ 10” 89.61.8659.5 1.52 4.463.65810 ml F 5’ 2” 104.62.0366.8 1.684.94.0900 ml M 5’ 8” 122.72.3280.5 1.945.6 4.61000 ml F 5’ 4” 116.02.1770.5 1.765.214.21000 ml M 5’ 11” 130.52.2888.0 1.935.474.6870 ml

40. Consequences of Adult Overweight and Obesity: • Diabetes • Heart Disease • Stroke • Dyslipidemia • Hypertension • Liver disease • Gallbladder disease • Kidney disease • Asthma • Sleep Apnea • Chronic Back pain This is a short list. I do not want to add to their problem. I use a more Ideal Body Weight. By using the patients height I use the weight for a BMI of 27 for that height.

42. In closing: • Consider the impact this has on your obese patients • Discuss this with your surgeon and implement, if they are agreeable • Use the weight for BMI of 27 • Even if you have a venous sat monitor, document serial venous gases • ALL other perfusion parameters should be as you normally do • Document BOTH numbers on your chart so you can see the flow range, from Ideal Body Weight BSA to Current Weight BSA (2.4 = 5.3 > 5.9)