Jay Porter
11.17.14
Answer Guide for Medical Nutrition Therapy: A Case Study Approach 4th
ed.
Case 29 – Metabolic Stress and Trauma: Open Abdomen
I. Understanding the Disease and Pathophysiology
1.
The patient has suffered a gunshot wound to the abdomen. This has resulted in an open abdomen.
Define open abdomen. The medical record describes the use of a wound “vac.” Describe this
procedure and its connection to the diagnosis for open abdomen.
An open abdomen is a procedure where the abdomen is left open after surgery to reduce the build
up of pressure within the abdominal cavity. A wound “vac” is the technique of vacuum-assisted
closure for the abdomen. A wound “vac” would be a used to close up the open abdomen and
reduce the risk of infection from the surgery.
2.
The patient underwent gastric resection and repair, control of liver hemorrhage, and resection of
proximal jejunum, leaving his GI tract in discontinuity. Describe the potential effects of surgery on
this patient’s ability to meet his nutritional needs.
Discontinuity of the GI tract could lead to malabsorption of many nutrients. If GI function is
compromised, alternative strategies for appropriate nutrient supply should be issued, such as
parenteral nutrition feeding, to ensure adequate kcal and protein needs. Failing to meet these
increased needs of calories and protein could delay wound healing and lead to nutrient
deficiencies.
3.
The metabolic stress response to trauma has been described as a progression through three phases:
the ebb phase, the flow phase, and finally the recovery or resolution. Define each of these and
determine how they may correspond to this patient’s hospital course.
The three phases of physiological responses to stress are Ebb, Flow, and Recovery. Ebb phase
typically occurs 2-48 hours and is associated with hypovolemia, tissue hypoxia, and decreased
cardiac and urinary output. Flow phase is dependent on the severity of the stress and characterized
by hypermetabolism and catabolism. Flow phase can also disrupt immune and hormonal signaling.
Recovery phase is the final step to the response to stress in which the body returns to normal
metabolic rate where we see a decrease in the hypermetabolic state and normal hormonal
responses. Nutrition support becomes the priority during the recovery phase as we can begin to
meet the body’s protein needs.
4.
Acute-phase proteins are often used as a marker of the stress response. What is an acute-phase
protein? What is the role of C-reactive protein in the nutritional assessment of critically ill trauma
patients? What other acute-phase proteins may be followed to assess the inflammatory stress
response?
Acute phase proteins are released by the liver during the inflammatory response. Acute phase
proteins are used to provide a negative feedback for the body during an inflammatory response. Creactive protein is a member of the acute-phase protein family that is released by the liver in
response to cytokine production from macrophages and neutrophils. CPR can be used as a
measure for the degree of inflammation during stress or trauma. Other acute phase proteins to
follow would be ceruloplasmin and ferritin.
II. Understanding the Nutrition Therapy
5.
Metabolic stress and trauma significantly affect nutritional requirements. Describe the changes in
nutrient metabolism that occur in metabolic stress. Specifically address energy requirements and
changes in carbohydrate, protein, and lipid metabolism.
The energy requirements of metabolically stressed patients are increased dependently on the
severity of the trauma. During a state of metabolic stress, substrate metabolism is abnormal
compared to normal conditions. Hypermetabolism, protein abnormalities, increased lipolysis, and
altered carbohydrate metabolism can be a result of stress related to trauma. Abnormal
carbohydrate metabolism related to trauma increases gluconeogenesis and reduces clearance of
serum glucose resulting in hyperglycemia. Lipolysis is increased due to a need for an alternative
energy source because of the reduced clearance of glucose from blood. Protein abnormalities are a
result of increased catabolism of protein and are shown by negative nitrogen balances for the
patient.
6.
Are there specific nutrients that should be considered when designing nutrition support for a
trauma patient? Explain the rationale and current recommendations regarding glutamine, arginine,
and omega-3 fatty acids for this patient population.
Carbohydrates, fats, proteins, and electrolytes should all be carefully considered when designing a
nutritional support formula for trauma patients. Increased protein needs, increased lipolysis, and
risk of refeeding syndrome are cases that need to be addressed for patient’s safety and wound
healing. Glutamine, arginine, and omega-3 fatty acids are known for their roles in wound healing
and immune response. Glutamine can play an essential role in gluconeogenesis and protein
synthesis. They body’s stores of glutamine are significantly decreased during times of metabolic
stress. Arginine has a high nitrogen content and can be beneficial in attempting to restore a
patient’s nitrogen balance to within normal limits while also thought to be an important player in
the immune response during a recovery from trauma. Omega-3 fatty acids are known for their
anti-inflammatory properties which is beneficial for recovery and mediating immune response.
7.
Using current evidence-based guidelines, explain the decision-making process that would be applied
in determining the route for nutrition support for the trauma patient.
ASPEN’s guidelines for the provision and assessment of nutrition support therapy for adult
critically ill patients states that enteral feedings should be started early within the first 24-48 hours
following admission and advanced toward feeding rate goal over the next 48-72 hours. Patients in
the ICU that have an absence of bowel sounds and/or evidence of passage of flatus and stool are
not required for the initiation of EN feedings. Parenteral nutrition should not be initiated
immediately postoperative; 5-7 days should separate the operation and PN initiation. PN should
only be initiated if nutrient needs are not being met by EN feedings.
III. Nutrition Assessment
8.
Calculate and interpret the patient’s BMI.
BMI: 102.7/(1.782) = 32.4 kg/m2 - Obese Class I
9.
What factors make assessing his actual weight difficult on a daily basis?
Assessing Mr. Perez’s weight on a daily basis is difficult due to his frequent trips to surgery and
VAC device.
10. Calculate energy and protein requirements for Mr. Perez. Use at least two methods (including the
Penn State) to estimate his energy needs. Explain your rationale for using each one. For the Penn
State calculation, the minute ventilation is 3.5 L/minute and the maximum temperature is 39.2.
Penn State: (.85 * Harris-Benedict) + Ve(33) + Tmax(175) - 6433
= (.85*2166) + (3.5*33) + (39.2*175) - 6433
= 2383.6 kcal/d * IF
= 2383.6*1.3
= 3098.7 kcal
25-30 kcal/kg:
25*102.7 = 2567.5 kcal
30*102.7 = 3081 kcal
11.What does indirect calorimetry measure?
Indirect calorimetry measures the respiratory differences of oxygen and carbon dioxide. IC can be
used to calculate a resting metabolic rate by measuring the caloric needs during a resting state
through the collection of expired air.
12. Compare the estimated energy needs calculated using the predictive equations with each other and
with those obtained by indirect calorimetry measurements.
Metabolic cart measurements for Mr. Perez show a REE of 3657 kcals. This resting energy
estimate is ~500 kcals greater than both the Penn State equation estimation and the 30 kcal/kg
estimation.
13. Interpret the RQ value. What does it indicate?
Mr. Perez’s RQ is 0.76. A RQ near 0.7 indicates the use of fats as the primary substrate for energy
needs.
14. What factors contribute to the elevated energy expenditure in this patient?
Multiple factors can contribute to the elevated energy expenditure seen in Mr. Perez’s IC. Trauma
from the GSW, multiple surgeries, and parenteral nutrition can all contribute to estimated caloric
needs.
15. Mr. Perez was prescribed parenteral nutrition. Determine how many kilocalories and grams of
protein are provided with his prescription. Read the nutrition consult follow-up and the I/O record.
What was the total volume of PN provided that day?
The current nutrition support is: Destrose: 140, CAA: 60, FAT/L: 20 goal Rate: 135 mL/hr.
Additionally Propofol @35 mL/hr to provide an additional 924 kcal. These combine to give Mr.
Perez a total of 3888 kcal and 194 g protein.
16. Compare this nutrition support to his measured energy requirements obtained by the metabolic cart
on day 4. Based on the metabolic cart results, what changes would you recommend be made to the
TPN regimen, if any? What are the limitations that prevent the health care team from making
significant changes to the nutrition support regimen?
The resting energy expenditure that was calculated by the metabolic cart shows Mr. Perez’s REE
is 3657 kcal/d. The TPN that is being provided supplies Mr. Perez with more than his resting
needs.
17. The patient was also receiving propofol. What is this, and why should it be included in an
assessment of his nutritional intake? How much energy did it provide?
Propofol is a relaxing agent given to patients who are going to receive anesthesia for surgical
procedures. Propofol provides significant amount of calories as lipids so it should be included
within the nutrition prescription. Mr. Perez’s dose of Propofol supplied 924 kcals.
18. The RD recommended that trickle feeds be initiated. What is this and what is the rationale? The RD
recommended the formula Pivot 1.5 for these trickle feeds. What type of formula is this, and what
would be the rationale for choosing this formula?
Trickle feeding is a very slow rate of enteral nutrition feeding, this would be important as to begin
to utilize the GI tract again since Mr. Perez has been on PN feedings for a few days. This slow
feeding would be beneficial since Mr. Perez has received many abdominal surgeries with his open
abdomen and VAC system. Pivot 1.5 is a formula designed for patients who are under metabolic
stress, surgical trauma, and burns. Pivot 1.5 has a very high protein content to help promote
protein synthesis and wound healing. Pivot 1.5 is designed to be well tolerated so this would be a
beneficial formula to choose for Mr. Perez’s trickle feeding to initially try to regain major function
of the GI tract.
19. List abnormal biochemical values for 3/29, describe why they might be abnormal, and explain any
nutrition-related implications.
Normal Value
Sodium
Patient’s Value
3/29
146
BUN
23
8-18
Creatinine Serum
Glucose
Phosphate
Osmolality
1.4
164
2.2
309.3
0.6-1.2
70-110
2.3-4.7
285-295
Protein
5.2
6-8
Albumin
Prealbumin
Alkaline
Phosphatase
ALT
AST
CPK
C-Reactive
Protein
HDL-C
VLDL
LDL
Triglycerides
1.4
3.0
540
3.5-5
16-35
30-120
435
190
182
245
4-36
0-35
55-170
<1.0
Trauma
Sustained
inflammation
40
110
140
274
>45
7-32
<130
40-160
Trauma, Diet
HbA1C
PT
INR
7.1
9
0.6
3.9-5.2
12.4-14.4
0.9-1.1
Cardiovascular
disease
Insulin resistance
Reason for
Abnormal Value
136-145
Loss of fluid
from GSW
Nutrition-Related
Implications
Risk for
Hypertension if
sustained,
Electrolyte
balance
Dehydration
Trauma
Hyperglycemia
Fluid loss
Hydration,
Electrolyte
balance
Delayed wound
healing, Edema
Truama, Surgery
PTT
WBC
RBC
Hematocrit
Specific gravity
Protein
Glucose
Ketones
Bact
Mucus
Yeast
21
15.2
3.2
35
1.045
Positive
Positive
Positive
5
5
2
24-34
4.8-11.8
4.5-6.2
40-54
1.003-1.030
Negative
Negative
Negative
0
0
0
20. Current guidelines recommend using a nitrogen balance study to assess the adequacy of nutrition
support.
a.
According to the Powell (2012) article (see bibliography below), what adjustments should be
made to assess for nitrogen losses through fistulas, drains, or wound output?
Achieving a positive nitrogen balance is a primary goal for nutritional support when
patients are in need of additional protein as a result of trauma. Patients who retain an
open abdomen after surgery are at increased risk for increased protein loss. Drains
collected from the open abdomen contain water, electrolytes, and proteins. Since these
proteins lost from drains are not incorporated in the calculation for nitrogen balance there
is a risk of improper protein feedings. If this additional loss of protein isn’t accounted for
wound healing and recovery from trauma could be severely delayed and compromised.
b.
A 24-hour nitrogen collection is completed for Mr. Perez with results of UUN 42 g. Calculate
his nitrogen balance.
Nitrogen Balance = (24 hour Protein Intake/6.25) - (24 hour Urinary Urea Nitrogen + 4)
Nitrogen Balance = (194/6.25) - (42 + 4)
Nitrogen Balance = -15
IV. Nutrition Diagnosis
21. Identify the nutrition diagnosis you would use in your follow-up note. Complete the PES statement.
Altered GI function RT gun shot wound trauma and surgery AEB gastric resection and repair
and altered lab values.
22. For the PES statement that you have written, establish an ideal goal (based on the signs and
symptoms) and an appropriate intervention (based on the etiology).
Parenteral nutrition feedings to meet increased needs for protein and calories.
Transition from PN to EN.
VI. Nutrition Monitoring and Evaluation
23. What are the standard recommendations for monitoring the nutritional status of a patient receiving
nutrition support?
Monitoring of electrolyte balances (phosphate, potassium, magnesium), blood glucose, and fluid
balance.
24. Hyperglycemia was noted in the laboratory results. Why is hyperglycemia of concern in the critically
ill patient? How was this handled for this patient?
Hyperglycemia is of concern because it is the most common problem with PN feedings and
contributes to the metabolic stress Mr. Perez is experiencing. Dextrose feeding should be reduced
to prevent hyperglycemia and related issues. Trickle feeding is a good way to improve tolerance
through the GI absorption and decrease complications from intolerances to feedings.
25. What would be the standard guidelines and subsequent recommendations to begin weaning TPN
and increasing enteral feeds?
Gradual reduction of TPN should be supplemented with increased EN feeding support. Monitoring
of the patient’s tolerance to EN feeding should be the determining factor for the rate for reduction
of TPN.