EN/PN study guide

What symptoms are G-tubes prone to causing in patients?

leakage, skin irritation, nausea, vomiting, bloating

What form of starch goes from the mouth to stomach?

partially hydrolyzed starch in form of oligosaccharides and shorter polysaccharides. amylase is inactivated by HCl

What is aspiration?

when regurgitated fluid enters the lungs, leading to infection or aspiration pneumonia

Can hypertonic solutions be given via central access?

yes, because the large vena cava dilutes PN via its large blood volume and high blood flow rate

Why would we want to feed someone in the jejunum past the ligament of Trietz and not into the stomach to avoid stimulating the pancreas?

Feeding infused into the jejunum beyond the ligament of Treitz may bypass the cephalic, gastric, and intestinal phase of stimulation of pancreatic secretion, is less likely to stimulate CCK and secretin, and may stimulate inhibiting polypeptides

Explain a gastrostomy and jejunostomy EN feeding.

It is a surgically placed tube directly into the stomach or jejunum by making a small incision in the abdominal wall (stoma) and is usually done during another preplanned surgery. This is used if EN is needed for more than a few weeks

Why is severe diarrhea a contraindication for enteral nutrition?

It results in electrolyte imbalance, dehydration, perianal skin breakdown, and wound contamination. Formula content may cause diarrhea: the type and amount of fiber, FODMAP content, osmolality, delivery mode, EN contamination, medication, infections (C. diff) **per ASPEN, clinicians need to look at the source of diarrhea before stopping EN. (Infectious diarrhea vs. osmotic diarrhea)

When would we transition someone from a nasal tube to a G-tube?

When the patient needs to be feed for a longer period of time

What is short bowel syndrome?

a group of problems related to poor absorption of nutrients. Short bowel syndrome typically occurs in people who have. had at least half of their small intestine removed and sometimes all or part of their large intestine removed.

What two things contribute to hypertonicity in PN formula?

amino acids and dextrose, not fat *as long as patient does not have delayed blood lipid clearance, lipids can be given peripherally even when other PN is given centrally

What symptoms are J-tubes prone to causing in patients?

increased chance of diarrhea

What is an ileus?

loss of peristalsis w/o structural obstruction

Glutamine is a key transporter of nitrogen, carbon, or ATP?

nitrogen

What steps can be taken to prevent dumping syndrome with EN?

tapering up infusion rates of EN, using continuous instead of bolus feeds, and using a isotonic formula

What happens to the bile salts in fat digestion?

the bile salts reach the ileum of the small intestines and enter the portal circulation into the liver (known as the enterohepatic circulation) to be recycled and used again

What occurs in the proximal 2/3rds of the jejunum in terms of fat digestion?

the monoglycerides and FAs are transported and absorbed across the hepatic enterocytes and packaged up to form chylomicrons that are transported into lymphatics to be circulated throughout the body

What is a PEG-J tube?

the tube enters the stomach and is fed through to the jejunum, rather than entering the body directly to the level of the jejunum. Also good for long-term

Explain what central access of PN is.

venous access delivered to the superior vena cava or right atrium. Access is achieved by catheter (tunneled or not) into the chest, or a PICC line, which is peripherally inserted (arm) and threaded up to the chest.

Explain a percutaneous endoscopic gastrostomy (PEG) and percutaneous endoscopic jejunostomy (PEJ) or PEG-J tube.

A lighted endoscope fed through the mouth down into the stomach (or jejunum) to guide where the abdominal incision is made and to guide placement of G-tube or J-tube once inserted in the incision. Good for months to years. Long-term EN support.

What is hypertonic?

A solution with a higher salt concentration than in the cells (cells shrink) LESS WATER THAN IN CELL

What is isotonic?

A solution with the same salt concentration as in cells

What is gastroparesis?

Stomach emptying is delayed so there is an increased risk for aspiration

What are trophic feeds?

a small volume of balanced enteral nutrition insufficient for the patient's nutritional needs but producing some positive gastrointestinal or systemic benefit. (about 10-15 mL/kg/d)

Explain what peripheral access of PN is.

achieved via a short IV cannula in the hand or arm and shouldn't be used for more than 10-14 days. PPN is used when central access is contraindicated or for short term PN.

What steps can be taken to prevent dumping syndrome with oral intake?

avoid fluids with meals, avoid fatty foods, avoid high sugar foods

Should EN be initiated in patients with acute pancreatitis?

enteral nutrition significantly reduces the mortality rate of severe acute pancreatitis compared to parenteral feeding. To maintain gut barrier function and prevent early bacterial translocation, enteral feeding should be commenced within the first 24 h of hospital admission. can be gastric or jejunal feeding of standard polymeric formula

Define continuous drip feeds.

given at a steady flow rate for as many hours is required to administer nutrients for the day assuming flow rate at 24-hours requires pt to be tethered to an IV pole or pump

What do bile salts from gallbladder do?

help with emulsification of lipids that allow for digestion by pancreatic lipase that break down TGs further into micelles (made up of bile salts, FAs, monoglycerides, cholesterol, phospholipids)

What are some reasons enteral access may not be able to be achieved or maintained?

hemodynamic instability, active GI bleeding, and severe neutropenic fever

Where does fat digestion begin?

in the mouth with lingual lipase and the further in the stomach with gastric lipase.

When would a nutritionally-at-risk patient unlikely to achieve sufficient oral or EN intake need to initiate PN?

within 3-5 days

how do we verify tube placement?

x-ray

What vitamins do not rely on fat absorption and digestion?

B vitamins and C

What hormones are produced in small intestines to digest fats?

CCK and secretin that are stimulated by fat droplets and stomach acid

Explain a nasoduodenal (ND) and nasojejunal (NJ) EN feeding.

It is a flexible tube that is fed through the nose, down the back of the throat, and terminates in the small intestines. This is more for short-term access only.

With PPN, it's important to maintain formula osmolarity below ______________________________. Why?

900-1000 mOsm/L to lower the risk of phlebitis (inflammation of vein) or thrombosis (blood clotting) due to large shifts into vascular compartments

Formulas with added fiber.....

contribute to normal bowel function, help patients with diarrhea and/or constipation BUT may clog tubes

What vitamins rely on fats to be absorbed in the jejunum?

A, D, E, K

When would a well-nourished stable patient who is unable to meet at least 50% of nutritional needs PO or via EN need to initiate PN?

initiate PN after 7 days

What are the 5 main indicators for enteral nutrition?

1. protein-energy malnutrition and inadequate oral nutrient intake for >5 days 2. meeting <50% of nutrient needs for 5-7 days 3. severe dysphagia 4. coma 5. low output enterocutaneous fistula

What is the ligament of trietz?

Ligament found at the transition from duodenum to jejunum (suspensory ligament)

Why are MCTs used in hydrolyzed formulas?

MCTs don't require emulsification and can be absorbed without transforming back to TGs

Where does the mechanical and chemical digestion of protein begin? With what enzyme?

Mechanical digestion in the mouth Chemical digestion in the stomach, with pepsinogen converted to pepsin (by HCl) that hydrolyzes peptide bonds. This breaks down protein into large polypeptides

What is a polymeric formula?

Polymeric/standard formulas are whole-nutrient formulas and require a functioning gastrointestinal tract that can absorb whole nutrients. - a type of enteral feeding formula

Are hydrolyzed formulas hypo- or hypertonic?

hypertonic, which can lead to excess fluid in the GI tract causing cramping, vomiting, nausea, and diarrhea

When can gut atrophy occur?

if the gut is not utilized for 2 or more weeks

What is diarrhea after tube feeding often due to? (6)

infections (gastroenteritis), antibiotics, medications with sorbitol, malabsorption, formula intolerance, and even rapid infusion/bolus feeds (manifests later than dumping syndrome)

Define bolus feeds.

intermittent feedings given several times throughout the day, often at meal times. Pts often transition from continuous drip in the hospital to bolus feeds when they leave to have more mobility during the day **bolus feeds may be difficult to tolerate, especially with post-pyloric access

What are some reasons for a mechanical bowel obstruction?

intestinal stenosis or stricture inflammatory disease severe adhesions

What are some reasons someone may need bowel rest?

ischemic bowel (lack of blood flow to bowels), severe pancreatitis, chylous fistula (leakage of lymphatic fluid)

When would NG, ND, and NJ tubes not be used?

long-term EN feedings or vomiting that could displace the tubes

Explain hydrolyzed formulas. Why are these used?

monomeric formula, pre-digested protein and carbs, fat in form of MCTs or oils Used with jejunal access, short bowel syndrome, and patients with impaired ability to digest nutrients.

How can osmolarity be calculated?

multiply dextrose (g/L) by 5 and amino acids (g/L) by 10 and add 300-400 for vitamins and minerals.

What is PPN typically used for?

only use PPN for supplemental PN or as a bridge to other therapy because large amounts can't be provided through small peripheral vein and they can't tolerate hypertonic solutions

Where does the last part of protein digestion occur?

polypeptides are further hydrolyzed by brush border enzymes (dipeptidase and amino peptidase) into tripeptides, dipeptides, and amino acids that are carried to the liver to synthesize new proteins or stored in form of glucose (glycogen) in the liver or FAs (triacylglycerides/TAGs) in adipose tissue

What are some reasons for motility disorders?

prolonged ileus, pseudo-obstruction, severe adhesions

Specialty formulas with glutamine can improve _____________ and _____________ metabolism and prevent ____________ atrophy.

protein and glucose metabolism and prevent GI atrophy

How can regurgitation of formula be prevented?

raising patients bed to at least 30 degrees

What is important to check before bolus feeds are given? and every 3-5 hours with continuous feeds?

residuals of 100-150 mL may indicate an obstruction or poor motility

What part of starch is not digested in small intestines? Where does it go?

resistant starch and it goes to the colon and undergo fermentation by the gut microbiota to form SCFAs

What are some reasons impaired absorption or loss of nutrients may occur?

short bowel syndrome bariatric surgery complications (high output intestinal fistula)

Where does most of the digestion and absorption of starch take place?

small intestines where pancreas releases more alpha-amylase that further breaks down glycosidic bonds

When would a controlled carb formula be used?

some institutions utilize controlled CHO formulas for patients with diabetes

Glutamine requirements are increased during....

stress (trauma, burns, sepsis, surgery, catabolic state)

Low CHO/high fat formulas can facilitate ______________ weaning because excess CHO is converted to ________ releasing CO2 (which is difficult to clear with impaired respiratory function)

ventilator weaning fat

What are examples of "prognosis that doesn't warrant aggressive nutrition support"?

1. if patient has intact, functioning GI tract with anorexia nervosa 2. if patient has mild dysphagia that can eat IDDSI foods and/or oral nutrition supplements 3. patient who is not at risk for malnutrition

What are the 5 indicators of parenteral nutrition?

1. inability to achieve or maintain enteral access 2. impaired absorption or loss of nutrients 3. mechanical bowel obstruction 4. need for bowel rest 5. motility disorders

What are the 4 aspects of gut atrophy?

1. inflamed intestinal cells, 2. blunt or malformed villi 3. leaky channels between intestinal cells 4. translocation of lumen contents into the blood stream

What are the 6 contraindications for enteral nutrition use?

1. intestinal obstruction, ileus, or hypo motility 2. severe diarrhea or vomiting 3. severe hemodynamic instability 4. major upper GI bleeding 5. prognosis doesn't warrant aggressive nutrition support 6. high output enterocutaneous fistula (>500 ml/d)

When would a moderately or severely malnourished patient in which oral intake or EN is not possible need to initiate PN?

ASAP

What is protein-energy malnutrition?

According to World Health Organization, protein energy malnutrition (PEM) refers to "an imbalance between the supply of protein and energy and the body's demand for them to ensure optimal growth and function".

In adult patients with ECF, what is the preferred route of nutrition therapy (oral diet, EN, or PN)?

After stabilization of fluid and electrolyte balance, we suggest that oral diet or EN may be feasible and tolerated in patients with low-output (<500 mL/d) ECF (suggesting no distal obstruction). However, patients with high-output ECF (>500 mL/d) may require PN to meet fluid, electrolyte, and nutrient requirements to support spontaneous or surgical closure of the ECF.

What is an enterocutaneous fistula?

An enterocutaneous fistula (ECF) is an abnormal connection that develops between the intestinal tract or stomach and the skin. As a result, contents of the stomach or intestines leak through to the skin. Most ECFs occur after bowel surgery.

Explain a nasogastric EN feeding.

It is a flexible tube that is fed through the nose, down the back of the throat, and terminates in the stomach. This is more for short-term access only.

Why might EN be preferred over PN in coma patients?

It is less expensive than parenteral nutrition and is preferred in most cases because of less severe complications and better patient outcomes, including infections, and hospital cost and length of stay. If the gut works, use it!!

What are the signs and symptoms of shock?

Cool, clammy skin Pale or ashen skin Bluish tinge to lips or fingernails (or gray in the case of dark complexions) Rapid pulse Rapid breathing Nausea or vomiting Enlarged pupils Weakness or fatigue Dizziness or fainting Changes in mental status or behavior, such as anxiousness or agitation

When would a metabolically unstable patient need to initiate PN?

Delay PN until condition is improved

Explain a healthy gut vs. gut atrophy.

Healthy gut: well-formed intestinal cells, normal villi, and effective tight junctions Gut atrophy: leaky gut (not tight junctions), villi atrophy, and bacterial translocation due to leak gut

What is the difference between an ileus and bowel obstruction?

Ileus and intestinal obstruction have similarities. However, ileus results from muscle or nerve problems that stop peristalsis. Known as a on-mechanical obstruction of bowel usually secondary to inhibition of peristalsis. Small bowel obstruction defined as mechanical obstruction of small bowel due to adhesions, mass, volvulus or other internal or external compression. a type of ileus known as paralytic ileus can cause a physical block due to a food buildup in the intestines.

Soluble fiber is converted to ________________ which is used by gut bacteria for food and helps maintain a health gut.

Short-chain fatty acids

Where would an EN tube be placed if someone had just had gastric surgery or has gastroparesis?

Since there is no need to avoid stimulating the pancreas, access just beyond the pylorus (in the duodenum) is sufficient.

Where is the main site of protein digestion and absorption?

The duodenum. polypeptides move from the stomach to the duodenum and are further broken down by enzymes (trypsinogen, chymotrypsinogen, and procarboxypeptidase) that are secreted by the pancreas

Explain how carbohydrates are digested?

The starch (amylose and amylopectin) are mechanically and chemically broken down. Chemical breakdown by alpha-amylase from salivary glands that break the glycosidic bonds of amylose and amylopectin.

What is the difference between dumping syndrome and diarrhea after rapid infusions/bolus feeds?

The timing of onset....dumping syndrome occurs within 15-60 minutes and diarrhea can occur later.

What are the brush border enzymes that break down starch in the small intestines?

These are inside the enterocytes...maltase, sucrase, and lactase

What is post-pyloric feeding? When would this be used?

This is when the feeding tube terminates beyond the stomach Use this to... 1. avoid stimulating the pancreas 2. due to recent esophageal or gastric surgery (risk of irritation and regurgitation) 3. due to severe gastroparesis

What are the indications for J-tube?

To avoid stimulating the pancreas if someone is having complications related to their G-tube such as leakage, skin irritation, nausea, vomiting, bloating

What is dumping syndrome? Explain the symptoms. What procedures is it usually seen after?

When gastric emptying is too rapid. It occurs when hypertonic contents enter the small intestine, causing an influx of fluid into the lumen. This leads to epigastric fullness, weakness, dizziness, vertigo, diaphoresis, tachycardia, and/or abdominal cramping. Seen after bariatric surgery, gastric resection, esophageal pull-up surgery, and sometimes with post-pyloric EN access. *can occur within 1 hour of eating or EN administration.

What does secretin stimulate?

bicarbonate secretion from pancreas to increase intra-lumenal pH for optimal environment of fat digestion

Define combination feeds.

bolus feeds during the day and continuous feeds at night.

What 3 hormones stimulate the release of pancreatic enzymes/juices?

colecystokinin (CCK) secretin vasoactive intestinal peptide (VIP)

What are some conditions that result in use of PN instead of EN or oral nutrition?

conditions that result in intestinal failure... ex: short bowel syndrome (extensive surgeries) inflammatory bowel disease (crohns) small bowel tumors mesenteric root or retroperitoneum tumors congenital malformations of the gut (small bowel atresia, gastroschisis, and aganglionosis) nectrotizing enterocolitis (NEC) absorptive impairment **don't need to know all of these for exam just name a few

What is dysphagia? How is it diagnosed?

difficulty swallowing A videofluoroscopy assesses your swallowing ability. It takes place in the X-ray department and provides a moving image of your swallowing in real time. You'll be asked to swallow different types of food and drink of different consistencies, mixed with a non-toxic liquid called barium that shows up on X-rays.

What are some examples of central line PN placement?

distorted local anatomy (such as for trauma), infection overlying the insertion site, or thrombus within the intended vein. Relative contraindications include coagulopathy, hemorrhage from target vessel, suspected proximal vascular injury, or combative patients.

What occurs when jejunal access feeds are directly given a hypertonic formula?

dumping syndrome: manifests as dizziness, sweating, tachycardia, cramping onset is between 15-60 minutes after feeds

What is starch used for after digestion in small intestine?

energy or stored as glycogen in the liver

What is a high-output fistula a contraindication for EN?

enteral nutrition in high output fistula was found useless, and didn't provide any benefit to the patients, and had compounded metabolic and management complications. EN does not replace the large amounts of fluid lost as quickly as it should.

What does CCK stimulate?

gallbladder contraction and release of pancreatic juice from pancreas

What are some examples of complications with PEG/PEJ tubes?

gastric content leakage, skin irritation, aspiration (PEG), and bleeding or bowel perforation (PEJ)

Define cyclic feeds.

given at a faster rate over a shorter period of time, and thus a faster flow rate must be tolerated. It's often used overnight so patients can freely move around during the day, or if a patient has a treatment schedule during the day (like chemotherapy) that precludes day time feeding.