CRITICAL CARE CASE STUDY - Weebly



Name: Dawn Ortiz

Parenteral Nutrition Support Case Study

A 60 yo male was admitted to the hospital after several days of worsening abdominal pain and nausea for which over-the-counter antacids provided no relief. His medical history was significant for hyperlipidemia; his surgical history was significant for recent knee surgery, hernia repair, and an appendectomy. He reported no known allergies.

On physical exam, the patient was found to be a well-nourished male, height 6'2" and weight 235 lbs. His vital signs were stable. Abdominal findings included tenderness in the left and right lower quadrants, normal bowel sounds, and no organomegaly. An abdominal series demonstrated a high-grade small bowel obstruction. A nasogastric tube was placed to decompress the patient's stomach. An enema was also given. Intravenous fluids were provided for hydration.

Laboratory values are as noted.

|TEST |NORMAL RANGE |ADMISSION VALUE |

|Hemoglobin |11-15 g/dl |16.9 |

|Hematocrit |32-45% |48.2 |

|Glucose |67-109 mg/dl |138 |

|BUN |8-25 mg/dl |19 |

|Creatinine |0.4-1.4 mg/dl |0.9 |

|Na |135-145 mEq/l |141 |

|Potassium |3.6-5.1 mEq/l |3.8 |

|Chloride |98-110 mEq/l |102 |

|Alkaline phosphatase |45-135 IU/l |92 |

|Triglyceride |< 250 mg/dl |103 |

|Calcium |8.5-10.5 mg/dl |8.4 |

|Magnesium |1.3-1.9 mg/dl |1.8 |

|Phosphorus |2.7-4.5 mg/dl |3.7 |

On hospital day 2, the patient was taken to the operating room and underwent an exploratory laparotomy and lysis of adhesions. Postoperatively, he received intravenous fluids. His nasogastric tube remained on continuous suction with high volume outputs ranging from 1200 to 1800 ml per day.

On postoperative day 6, the patient was referred to the nutrition support service for initiation of TPN due to delayed return of bowel function and prolonged post-operative ileus. His weight was now 220 pounds. Part of this weight loss could be attributed to a net negative fluid balance resulting from large volume nasogastric drainage. Vital signs were stable and his lungs were clear. His abdomen was soft and nontender. He had minimal bowel sounds and had not passed any flatus. The nasogastric tube was still suctioning and had been draining approximately 1700 ml per day. His urine output was adequate.

The decision was made to begin TPN. Although the patient had no pre-existing nutritional deficits, he had experienced significant weight loss during the hospitalization and continued to have high-output nasogastric drainage. A triple-lumen catheter was inserted into the superior vena cava. Placement was confirmed by x-ray.

Questions

1. List at least 5 indications for the use of TPN:

• Ulcerative colitis

• Bowel obstruction

• Short bowel syndrome (from surgery)

• Patient is well nourished and will need TPN for at least 5 days or more

• The patient is malnourished with a non-functional gut (start slow within 24-48 hours)

• Intractable vomiting

• Mabsorption in the gut

2. Name 5 contraindications for giving a patient TPN

• The gut is functioning and there is no GI distress

• The patient is well nourished and will not need TPN for a minimum of 5 days

• The patient is at risk for infection

• EN may start within 5 days

• Ethically, TPN should not be used to prolong life without quality of life in the eyes of the patient, family and medical support team

3. Calculate the patient's energy and protein needs. Show your calculations and weight basis.

Weight loss: 235# to 220# in 8 days, start feeding low and slow with initial goal rate as follows for patient with small bowel obstruction (feeding weight= 100 kg):

Energy needs: 20-25 kcal/kg ( 2000-2500 kcal/day, slowly increase needs to goal rate of 30 kcal/kg( 3000 kcal/day

Protein needs: 1.5-2 g/day( 150-200 g/day

4. Calculate the patient's fluid needs.

Output from NG tube = 1700 mL; approximate urine output= 1000 mL

Fluid needs: 2700 + 500 ( 3200 mL/day

Or 40 mL/kg ( 4000 mL/day

 

5. Make recommendations for dextrose, amino acids, lipid and total volume for the TPN solution. (Calculate based on the example given in the TPN worksheet). The solution will be given as a three-in-one admixture.

2700 calories and

175 grams protein

in total volume of 3600 mL.

1. Amino Acids:

Step1: 175g : 1.5 liter = 263 g/L

Step2: 175g x 4 kcal/g = 700 kcal

2. Dextrose:

Goal… about 55% of total calories

Step1: 2700kcal x 0.55 = 1485 kcal

Step2: 1485kcal / 3.4 kcal/g = 437g

Step3: 437g x 1.5 liter = 656 g/L

3. Fat

Remainder of calories

515kcal / 10 kcal/g = 52g

The recommended TPN solution would be:

TPN 150 mL/hour

Amino acids 263 g/L

Dextrose 437 g/L

Fat 52 g/day

to provide 2700 calories and 175 grams protein per day

6. List four potential complications of TPN

• Blood glucose management

• Matching insulin requirements

• Fluid management

• Electrolyte balance

7. List the labs and nutritional parameters for monitoring TPN.

At my hospital, we have a nutrition support team consisting of an endocrinologist, nutrition pharmacist and the dietitians to monitor all the TPN patients.

• Check BMP, Mg and Phos daily until stable then PRN

• Weight and I/O daily

• Check INR weekly or more often if pt on an anticoagulant medication

• Calcium PRN

• TG and CMP weekly

• Prealbumin at TPN initiation and then every 5-7 days

• Per nutrition assessment: CRP, ammonia, selenium, copper, zinc and B12

• Vitamin D at least monthly

• Ft4 and TSH monthly

8. What lab value is used to monitor lipids?

  Triglycerides. Lipids should be withheld from TPN if TG ≥ 300 mg/dL.

9. List the consequences of excess fat administration:

 

The administration of excess lipids in a TPN solution may result in hyperlipidemia, cholestasis, diabetes, sepsis, pancreatitis and hepatic steatosis from altered lipid metabolism. 2.5 gm fat/kg/day is the upper limit for lipids in a TPN solution per day.

10. Describe three-in-one admixture or total nutrient admixture (TNA). List the advantages and disadvantages:

In a three-in-one solution dextrose, amino acids and lipids are hung together in one bag.

Pros: less nursing time, decreased chance of outside contamination

Cons: limited additives, cannot see particulate matter 

11. What is the maximal amount of carbohydrate tolerated?

The maximum amount of carbohydrate tolerated in PN is 5 mg/kg/min and if the patient is critically ill only 4 mg/kg/min.

12. List the consequences of excessive carbohydrate administration.

Excessive carbohydrate may cause the patient to become hyperglycemic, and more serious complications such as hepatic steatosis. High carbohydrate may also raise the respiratory quotient to greater than 1, causing respiratory issues, and possibly cause lipogenesis.

13. Name 4 differences between TPN and PPN.

• Total Parenteral Nutrition means that the patient is receiving their total nutrition from TPN, while Peripheral Parenteral Nutrition means the patient is receiving partial nutrition from PPN and relying on other sources for the rest.

• TPN is administered in a higher concentration than PPN

• TPN is only delivered through a large vein, such as the superior vena cava, whereas PPN can be delivered through smaller, peripheral veins.

• TPN is used for more long term use than PPN.

14. What is the maximum osmolality recommended for PPN? Why is this important?

PPN osmolality should be kept between 600-900 mOsm/L. This is important to not fluid overload the veins, which may result in thrombophlebitis.

15. Define cyclic TPN. What are the advantages? What needs to be considered prior to changing from continuous to cyclic TPN?

Cyclic TPN is 10-16 hour infusion, which mimics the circadian rhythm of eating and fasting. This is less taxing than continuous TPN on the digestive and endocrine systems thus reducing hepatic complications. Therefore cyclic TPN may improve quality of life. When switching from continuous to cyclic TPN, the nutrition support team make sure the patient has demonstrated tolerance to final solution and rate. The infusion period should be 4 hour increments reaching goal in 2-3 days with tapering TPN at start and end of infusion.

16. Complete the following cyclic TPN calculation: 65 yom receiving TPN for 16 hours daily. Total volume needed is 1700ml. What is the 1 hour taper up and taper down rate? What is the maximum infusion rate?

Total volume: 1700 mL

Max infusion rate: 1700 mL/15 = 113mL/hr

1 hour up and down taper rate: 133mL/2 = 57mL/hr

17. A septic patient needs high protein. They have CHF so are on a fluid restriction. TPN order is 6% amino acids, 15% dextrose and 150ml IL at 40 ml/hr. The pharmacy calls to tell you they can’t make the TPN. Why? How much fluid would you need to make this TPN? (Remember, you need 100ml fluid to compound 10 gm amino acids and 100ml fluid to compound 70 gm dextrose + an additional 100-200 ml for the electrolyte, vitamins, etc)

40 mL/hr of TPN only provides 960 mL total volume.

15% of 960 mL= 144 g dextrose requiring 5 mOsm per gram (720 mL)

6% of 960 = 58 g protein requiring 10 mOsm per gram (580 mL)

150 mL lipids

100 mL for electrolytes

Therefore the minimum fluid necessary for this solution would be 1550 mL total volume and 65 mL/hr.

18. A patient may receive Propofol in the ICU. What is propofol? How many kcals/ml does it contain? How may this impact your nutrition recommendations?

Propofol slows the activity of the brain and nervous system, which helps relax patients before or after surgery. It is also often used to help sedate patients on a ventilator. Propofol is a lipid solution containing 1.1 kcal/mL which must be incorporated into the total amount of fat and calories the patient is receiving.

19. What type of IVF should be avoided in the dehydrated patient and why? What type of IVF should be given?

An isotonic solution such as lactated ringers or normal saline should be used to treat volume depletion dehydration. Isotonic solutions have the same tonicity as plasma creating an environment where water does not enter or leave the cell. D5 is a good treatment for hypernatremic dehydration, because it does not contain sodium chloride. A hypotonic solution such as ½ normal saline is not a good option to treat dehydration because the cells will draw the water in.

20a. Why is normal saline considered isotonic?

Isotonic solutions have an osmolality of 240 - 340 mOsm/L. NS has an osmolality of 280-300 mOsm/L.

20b. Why is 1/2 normal saline considered hypotonic?

Hypotonic solutions have an osmolality of less than 240 mOsm/L. 1/2NS has an osmolality of 154 mOsm/L.

20c. Why is a solution of 5% dextrose in normal saline considered hypertonic?

A hypertonic solution is one that has an osmolality greater than 340 mOsm/L. 5% dextrose has an osmolality of 560 mOsm/L. Patients administered this type of IV must be watched for fluid overload. Also the dextrose must be calculated into the patient’s total calories being administered.

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