Ch 13: Complications of EN Flashcards
Most common problem r/t N/V
Delayed gastric emptying
Potential causes of N/V
- diabetic gastropathy
- hypotension
- sepsis
- stress
- anesthesia/surgery
- infiltrative gastric neoplasms
- autoimmune diseases
- surgical vagotomy
- opiate analgesics (morphine sulfate, codeine, fentanyl)
- anticholinergics (chlordiazepoxide HCl and clidinium bromide)
- excessive rapid infusion of formula
- infusion of cold solution or one containing high amounts of fat and fiber
Interventions for N/V
- Reduce or d/c all narcotics
- Switch to low-fiber low-fat and/or isotonic formula
- Administer feeds at room temperature
- Temporarily reduce feeding rate by 20-25 ml/hr
- Change infusion from bolus to continuous
- Prokinetics (metoclopramide or erythromycin)
What should you do if N/V occurs as rate of administration or bolus volume increases?
Reduce to greatest tolerated amount and reattempt advancement after symptoms subside
If these attempts fail, obtain SB access
ASPEN/SCCM stance on routine checks of GRV in critically ill patients
ASPEN/SCCM does not recommend routine checks of GRV in critically ill patients
What should you monitor in patients who c/o nausea with EN?
stool frequency
Causes of distention and nausea
- Obstipation or fecal impaction can lead to distention and nausea
- Cdiff can cause distention and vomiting
Distention/bloating can be caused by:
- GI ileus
- obstruction
- obstipation
- ascites
- diarrheal illness
- rapid formula administration
- infusion of very cold formula, use of fiber formula (fermentation)
Suspect ileus or bowel obstruction based on & how to confirm?
- physical exam and symptoms
- can be confirmed by a flat and upright abdominal x-ray
* Impractical in hospitalized patients
* “Plain” films may be nondiagnostic
What is an appropriate screening method if ileus or obstruction is suspected?
Plain radiology
When distention and question of feeding tube placement:
Contrast + follow up x-ray or fluoroscopy
- Continue EN if intestinal appearance is normal, even with distention
- Hold feeds if motility is poor, bowel is markedly dilated, or discomfort is too severe
Maldigestion & clinical manifestations
Impaired breakdown of nutrients into absorbable forms (e.g., lactose intolerance)
Clinical manifestations: bloating, abdominal distention, diarrhea
Malabsorption
: defective mucosal uptake and transport of nutrients (fat, CHO, protein, MN, lytes, water) from the small intestine
Clinical manifestations of Malabsorption
- unexplained weight loss
- steatorrhea
- diarrhea
- signs of macro or MN deficiency (anemia, tetany, bone pain, pathologic fractures, bleeding, dermatitis, neuropathy, glossitis)
Screening methods for malabsorption:
- Gross/microscopic exam of stool
- Qualitative determination of fat and protein content of a random stool collection
- Measurement of serum carotene concentration
- Measurement of serum citrulline levels
- Measurement of d-xylose absorption
- Radiologic exam of intestinal transit time and motility
When lab data, history, and/or radiologic exam suggest maldigestion/malabsorption, diagnosis can involve:
- I/Os (stool collections for quantitative fecal fat assessment)
- Endoscopic SB BX – diagnosis of celiac disease, tropical sprue, Whipple disease
- Tests for maldigestion/absorption of specific nutrients:
* Lactose tolerance test
* Schilling test to screen for abnormal absorption of B12
* EFA profile for lipid malabsorption
* Radioisotopic test to identify iron, calcium, AA, folic acid, pyridoxine, and Vit D malabsorption
Causes of maldigestion/malabsorption:
- Gluten sensitive enteropathy
- Crohn’s disease
- Diverticular disease
- Radiation enteritis
- Enteric fistulas
- HIV
- Pancreatic insufficiency
- SBS
- SIBO
Use of semi-elemental formulas when malabsorption is suspected
Weak data supports use of predigested enteral formulas to prevent intolerance when malabsorption is suspected
What is the most commonly reported GI side effect in patients receiving EN?
Diarrhea
Definitions of diarrhea
Abnormal volume or consistency of stool
- > 500 mL output x24 hours
- > 3 stools/day for at least 2 days
Normal stool water is
250-500 mL/day
Etiologies of diarrhea
- medications
- primary GI disease
- bacterial infection
Less likely causes of diarrhea:
- characteristics of the formula (osmolality, fat content),
- specific components of the formula (lactose)
Drug-induced diarrhea can be caused by:
- 10-20g sorbitol can cause GI side effects like diarrhea
- Drugs with effects on the gut – abx, PPIs, prokinetics
- Abx-associated diarrhea (AAD) is a common medication effect (25% treated with abx)
- Cdiff affects 10-20% of those who develop AAD
Most drugs and lytes (potassium) should be
mixed with 30-60 mL water per 10-mEq dose to avoid direct irritation of gut
GI diseases that can cause maldigestion or secretory diarrhea
- IBD
- SBS
- gluten-sensitive enteropathy
- AIDS
PN vs EN in GI diseases
- PN may be required in some disease states
- In other diseases, special enteral products are proposed to facilitate absorption
mOsm of TF vs Electrolytes
- Highest osmolality of a TF is ~750 mOsm/L which is ~2.5x greater than serum
- Electrolyte supplements have osmolalities that range from 5000-7000 mOsm/L – more likely to cause osmotic diarrhea
Suspicion that EN is causing osmotic diarrhea:
switch to isotonic formula
Formula dilution
has not been shown to improve tolerance and it contaminates the formula
Lactose and illness
Patients can develop transient lactase deficiency during illness
What formulas are recommended in most patients starting EN
Polymeric enteral formulas with intact protein
Management strategies of diarrhea
- Medical assessment to rule out infectious or inflammatory causes of diarrhea, fecal impaction, diarrheagenic meds
- Use antidiarrheal agent (loperamide, diphenoxylate, paregoric, octreotide) when Cdiff is ruled out or is being treated
- Change formula type (intact protein to peptide-based formula)
- Add soluble or insoluble fiber to medication regimen or change the TF formula to one with fiber – except in critically ill patients
- Multiple small studies have demonstrated adding soluble fiber to EN improves diarrhea and adding fiber to EN is the recommended SOC
- Continue EN as tolerate and initiate supplemental PN
Fiber-containing enteral formula vs modulars
Fiber-containing enteral formula preferred > modulars because the latter can clog feeding tubes
Fiber as an intervention with diarrhea/TF
Addition of fiber to EN regimen or changing TF formula should NOT be primary intervention OR the end of the evaluation/intervention for diarrhea
Bacterial overgrowth in the GI tract can cause
- severe enteritis with diarrhea
- abdominal cramps and pain
- hypoalbuminemia
- protein catabolism
- cachexia
- fever
- sepsis
SIBO increasingly seen in which patient populations?
s/p Roux-en-Y GBP surgeries
SIBO & hydrogen breath tests
Hydrogen breath tests can provide false-negative results
Consider SIBO as differential diagnosis if
patient with prolonged abx therapy who presents with bloating, abdominal pain, and/or unexplained catabolism/hypoalbuminemia
Prolonged use of what drug increases risk of SIBO?
broad-spectrum abx
SIBO treatment:
often empiric and includes abx – nonabsorbable abx are preferred
What patients are at greater risk for morbidity and mortality r/t formula contamination?
- Neonates
- Critically ill and immune-suppressed patients
- Compromised gastric acid microbial barrier
Open delivery systems & hang time
- provide TF via syringe or poured into bag
- Hang time of 4-12 hours
Closed delivery systems –
- prefilled, sterile bottles or non-air dependent containers accessed via spike or screw-top tubing
- Hang time of 24-48 hours
Hang time of reconstituted powdered formulas or formulas with added modulars delivered by gravity drip or pump
should not hang for >4 hours at room temperature
Powdered formulas vs liquid formulas
- Powdered formulas are not required to be sterile and can contain contaminants
- Liquid formulas undergo heat sterilization
What should you do with excess formula when preparing a feed?
Refrigerate excess formula that is leftover after intended volume is poured into a feeding system – max 24-48 hours
Use of a blender to add CHO and protein modulars to a formula
carries a high risk for contamination during mixing and should be avoided
Formula containers, hang time, bags
- Clean lids of cans with isopropyl alcohol and let dry before pouring formula into delivery receptacle
- Do not add additional formula to the feeding bag until the previous formula has infused
- Feeding bag should be changed every 24 hours
Closed delivery systems still carry a risk of contamination d/t
attachment tubing (touch contamination)
Reduce the incidence of diarrhea in closed systems (ex: spike sets) by
replacing the tubing for closed systems every 24 hours
Contamination can occur in a retrograde manner if
endogenous microorganisms (stomach, throat, lungs) reproduce within the feeding tube and then migrate into the enteral delivery system
Checking GRV & risk of contamination
Checking GRV pulls potentially pathogenic microorganisms up the feeding tube and can lead to a contaminated feeding tube hub and contaminated gloves
Y-ports of enteral delivery systems
are used to deliver meds and water flushes to minimize disconnection of enteral formula
Lopez valves are 3-way stopcocks that are frequently attached to enteral feeding tubes that
do not contain a clamp (NG, balloon gastrostomy, balloon gastrojejunostomy, jejunostomy tubes)
* Swivel to block or allow fluid passage
* One study suggests changing Lopez valves at intervals of 3 days or less (or even at each tubing change) to avoid development of bacterial biofilm
What type of water should be used in formulas or modulars that require reconstitution or dilution?
sterile water
Small bowel dilation is rarely found in
uncomplicated constipation
In patients who have constipation and require a fluid restriction:
use a stool softener (docusate sodium or docusate calcium, or various emollients) and a laxative or cleansing enema
Chronic use of stimulants (senna) often results in
tachyphylaxis and is not indicated
If adding fiber to the enteral regimen, administering a minimum of _ _ _ can help prevent solidification of waste in the colon and constipation
1 mL of fluid per kcal
What is recommended in prevention of constipation in hemodynamically stable patients?
Short-chain fibers
In older adults, impaction may be the cause of
confusion and agitation
ASPEN/SCCM recommends avoiding fiber in patients who are
not hemodynamically stable
What is typically seen in ischemia with EN?
Nonocclusive bowel necrosis (NOBN)
- associated with a high degree of morbidity and possibly with death
Populations that may be at greater risk for NOBN
- Neonates
- Critically ill and immune-suppressed patients
- Compromised gastric acid microbial barrier
All reports cite _ _ _ as precipitating factors for NOBN
hypotension and/or hypovolemia
Aspiration of saliva is normal during
sleep
Progression of aspiration to aspiration PNA is hard to predict and may depend on
quantity and acidity of formula in addition to particulates and contaminants in the formula
Risk factors for aspiration:
- low HOB
- vomiting
- gastric TFs (vs SB feeds)
- low Glascow coma score (GCS)
- GI reflux disease
Pulmonary aspiration can occur when a patient inhales
oropharyngeal and gastric secretions
After an episode of emesis and regurgitation, aspiration of TF or vomit can be presumed if patient develops
- dyspnea, cyanosis, and agitation
- and if there is evidence of new infiltrate on chest film
FD&C Blue No. 1 dye & TFs/checking aspiration risk
- Blue discoloration of body parts and fluids
- Refractory hypotension, metabolic acidosis, and death reported
Why is checking tracheal secretions with glucose oxidase strips not fully accurate?
High tracheal concentrations of glucose can be found in aspirates of nonfed patients and those with hyperglycemia, as well as in aspirates of some blood
Accuracy of GRV measurements can be influenced by numerous factors including:
- diameter and position of feeding tube tip
- number and location of tube’s openings
- patient’s position (altering level of stomach fluid)
- skill of the clinician
Raising HOB 30-45 degrees during gastric feeds has been associated with
decreased esophageal and pharyngeal reflux of gastric contents and a lowered incidence of aspiration PNA
2016 ASPEN/SCCM guidelines re: GRV
- Suggest not using GRV as part of routine ICU care in patients receiving EN
- If GRV still being used, recommend avoid holding EN for GRVs <500 mL in the absence of other signs of feeding intolerance (quality of evidence: low)
G-tubes and GRV
Gastrostomy tubes are positioned in the anterior abdomen and are unlikely to allow full withdrawal of stomach contents during GRV checks
* GRV >100 mL with g-tube has been suggested as trigger for evaluation of GI symptoms
TF patients should be assessed for signs of TF intolerance – abd distention, feeling of fullness, discomfort, N/V at _ _ _ hour intervals
4 hour
If tube placement is questionable,
a radiograph should be obtained
Unless a patient is vomiting, GRV of _ _ _ should be re-instilled to replace _ _ _
- GRV of 250 mL
- replace fluid, lytes, and feeding formula
Measures to reduce aspiration risk:
- HOB elevation at least 30-45 degrees or positioning patient upright in chair
- If contraindicated, reverse Trendelenburg position
- Good oral care BID (with chlorhexidine in critically ill patients)
- Continuous TF schedules
- Use of minimal sedation techniques
- Appropriate and timely oropharyngeal suctioning (ex: prior to lowering HOB, deflating cuff of trach, or extubation)
Potassium – a total body deficit of _ _ _ is required before serum levels drop below normal
80 mEq
Absorption of glucose from continuous feeds is more affected by:
A- the rate of CHO delivery
B- glycemic index
Absorption of glucose from continuous feeds is more affected by the rate of CHO delivery than glycemic index (which refers to rate of glucose increase after a bolus)
Dehydraton is associated with
- increased risk of falls
- pressure ulcers
- constipation
- UTIs
- respiratory infections
- medication toxicities
Persistent dehydration can lead to:
delirium, renal failure, coma, and death
Which age group is at a greater risk for dehydration?
Older adults are at greater risk for dehydration – have lower water reserves d/t decreased LBM that occurs with aging
Early signs of dehydration:
- Dry mouth and eyes
- Thirst
- Light-headedness (especially when standing)
- Headache
- Fatigue
- Loss of appetite
- Flushed skin
- Heat intolerance
- Dark urine with strong odor
Tongue dryness can be a quick, reliable, cost-effective way to
identify dehydration in older adults
*** As long as other etiologies of dry mouth – diuretic and anticholinergic use – are ruled out
Signs of progressive dehydration:
- Dysphagia
- Clumsiness
- Poor skin turgor (sternum: more than 2 seconds)
- Sunken eyes with dim vision
- Painful urination
- Muscle cramps
- Delirium
Lab results for dehydrated patients usually show an elevation, relative to pre-dehydration levels:
- Elevation of BUN, plasma osmolality, Hct
- Serum Na levels can be elevated, low, or normal - dependent on etiology of dehydration
In dehydration, BUN level usually rises out of proportion to the usual BUN-Cr ratio of
20:1
Evaluate in context of nutrition state and underlying renal function
BUN reflects
protein intake, hydration status, and renal function
Example: a severely cachectic pt with renal failure, a Cr level significantly lower than 1 mg/dL, a BUN >100 mg/dL, and a BUN:Cr ratio > 100:1 may still be adequately hydrated
Dehydration – urine-specific gravity and urine output
Elevated urine-specific gravity > 1.028 + low UOP usually reflects dehydration
Normal urine-specific gravity: 1.010 to 1.025
Minimum UOP required to remove waste:
30 mL/hr ~ 700 mL/day
UOP for adults:
0.5-2 mL/kg/hr
Output of at least _ _ _ is useful as a guideline for adequate UOP
1 mL/kg/hr
For pts with fever: increase fluid by _ _ _ % per degree Celsius above _ _ _
Increase fluid by 12% per degree Celsius above 37.8
