Book questions Flashcards
The administration of 1 liter 0.9% sodium chloride (NaCl) to a normonatremic patient will increase the intravascular and interstitial fluid compartments by:
- 1000 mL and 0 mL, respectively
- 0 mL and 1000 mL, respectively
- 750 mL and 250 mL, respectively
- 250 mL and 750 mL, respectively
- 250 mL and 750 mL, respectively
A solution of 0.9% NaCl (154 mEq/L) is isotonic and, 4. therefore, does not contribute to an osmotic gradient. Isotonic saline enters and remains in the ECF. Thus, administering
1 liter 0.9% NaCl expands the ECF by 1 liter. The intravascular volume accounts for 25% of the ECF and will expand by 250 mL. The remaining 750 mL will be distributed to the interstitial fluid compartment.
Assuming the same weight and serum sodium concentration, which of the following patients has the greatest free water deficit?
1. A 35-year-old man
2. A 75-year-old man
3. A 35-year-old woman
4. A 75-year-old woman
- A 35-year-old man
The correct answer is 1. Free water deficit is calculated as follows:
Free Water Deficit = TBW × [1 – (140/Serum Sodium)]
where free water deficit and total body water (TBW) are measured in liters and serum sodium is measured in mEq/L. Given the same body weight and serum sodium concentration, the only variable is the percentage of TBW. The percentage of TBW increases as the proportion of lean body mass (LBM) to adipose tissue increases. In general, the percentage of TBW decreases with age and is lower in females than in males. Younger men would be expected to have the highest proportion of LBM and
the highest percentage of TBW and would therefore have the largest free water deficit.
A patient with severe intractable nausea and vomiting is at risk for which of the following acid-base disorders?
- Hyperchloremic metabolic alkalosis
- Hyperchloremic metabolic acidosis
- Hypochloremic metabolic alkalosis
- Hypochloremic metabolic acidosis
The correct answer is 3. Gastric fluids contain approximately 130 mEq chloride (Cl–) per liter and are very acidic (pH 1 to 2). Losing large amounts of gastric fluids via vomiting, especially for a prolonged period of time, can result in a hypochloremic metabolic alkalosis as the loss of acid from the stomach leaves the body with a relative excess of alkali.
Metastatic calcification is a complication of
1: hyperkalemia
2: hypokalemia
3: hyperphosphatemia
4: hypophosphatemia
3: hyperphosphatemia
A patient has had a NG tube to suction for 48 hours secondary to a post-operative ileus. Which of the following electrolytes will be lost?
1: Bicarbonate
2: Potassium
3: Calcium
4: Phosphorus
2: Potassium
A patient in your intensive care unit has acute severe diarrhea. Which of the following acid-base disorders is likely to occur?
1: Metabolic acidosis
2: Metabolic alkalosis
3: Respiratory acidosis
4: Respiratory alkalosis
1: Metabolic acidosis
Which of the following practices is most likely to succeed in improving oral nutrient intake in patients with a prolonged history of weight loss due to poor intake, nausea, and depressed appetite?
- Providing a high-energy oral liquid supplement 3 times daily
- Offering 6 small, low-fat meals daily
- Ordering fiber-supplemented snacks 3 times daily
- Planning primarily solid meals and limiting fluids
- Offering 6 small, low-fat meals daily
When patients experience a prolonged negative B energy balance, the stomach’s adaptive accommodation function declines; therefore, patients may not be able to consume their goal nutrient targets in 3 regular-sized meals because of a feeling of fullness.1 Eating 6 small meals may be a more realistic option. To address nausea, measures should be taken to prevent slowing of gastric emptying, which could potentiate nausea. These measures may include limiting high-fat foods. Providing high-energy or high-fiber supplements initially may not be the best
recommendation because, like fat, energy density and fiber content can slow gastric emptying. Answer D is not a good choice because providing fluids, not limiting them, facilitates gastric
emptying.
Which of the following statements explains why fermentable fiber is a beneficial addition to enteral formulas?
- Colonic bacteria act on the fiber to produce short-chain fatty acids (SCFAs) that provide an energy source to the intestinal mucosa.
- Colonic bacteria act on the fiber to produce SCFAs, which, in turn, exert trophic effects on the intestinal mucosa.
- Fermentable fiber may help control diarrhea by slowing gastric emptying.
- All of the above.
- All of the above.
Although more confirming evidence is needed, the addition of fermentable
fibers to enteral formulas likely has multiple beneficial effects, both in the healthy gut and in the malfunctioning gut. Fermentable fibers (eg, pectin, gums, fructooligosaccharides [FOS]) are metabolized by colonic bacteria to produce SCFAs. SCFAs have multiple benefits for the colonic mucosa. These benefits include providing a significant source of energy for and exerting trophic
effects on the intestinal lining. However, fiber is not recommended for patients with diarrhea caused by Clostridium difficile pseudomembranous colitis (PMC) or during low-flow states.
Which of the following is the largest component of total energy expenditure (TEE)?
- RMR
- Thermogenic effect of digestion
- Physical activity
- Metabolic stress
- RMR
The thermogenic effect of digestion is generally thought to contribute no
more than 10% to TEE. Activity contributes 5% to 30% to TEE. With the exceptions of burn and sepsis, metabolic stress contributes less than 50% to TEE. However,min almost all situations, RMR constitutes 60% to 75% of TEE.
Which of the following is the most commonly used method for assessing energy expenditure?
- Indirect calorimetry (IC)
- Predictive equations
- The reverse Fick equation
- Doubly labeled water
- Predictive equations
Most nutrition support feeding regimens are based on predictive equations used to assess energy expenditure. The measurement of energy expenditure via IC is more accurate
than predictive equations but is underused because the equipment is expensive to purchase and operate, and because some patients cannot be measured for various technical and physiological reasons.
Which parameter is measured when using IC?
- Heat loss
- Catabolic rate
- Gas exchange
- Free energy balance
- Gas exchange
Indirect calorimeters measure respiratory gas exchange (the difference between inspired and expired oxygen and carbon dioxide). If proper testing conditions are observed,
respiratory gas exchange is equivalent to metabolic gas exchange (the consumption of oxygen and production of carbon dioxide [CO2] at the cellular level). Gas exchange data are converted to RMR using the Weir equation
You are determining the energy intake target for a 53-year-old, critically ill, male patient who is about to start enteral feeding. He is 170 cm in height and weighs 150 kg. His body mass index (BMI) is 51.9 and his ideal body weight is 70 kg. Body temperature is 37.3 degrees Celsius and minute ventilation
is 12.5 L/min. Based on the 2016 American Society for Parenteral and Enteral Nutrition (ASPEN) guideline for calculating a goal energy intake for such a critically ill patient, 1 what energy value would you use as the basis for the feeding plan?
- 1750 kcal/d (25 kcal per kg ideal body weight)
- 1225 kcal/d (70% of the calculated 25 kcal per kg ideal body weight)
- 2250 kcal/d (25 kcal per kg adjusted body weight)
- 2615 kcal/d (Penn State equation)
- 1750 kcal/d (25 kcal per kg ideal body weight)
The ASPEN guideline states that the goal intake for all classes of obesity should not exceed 65% to 70% of target energy expenditure as measured by IC.
For class III obesity (BMI equal to or greater than 40), an intake of 22 to 25 kcal per kg ideal body weight is recommended.
The Penn State equation (answer D) has been validated as being among the most
accurate ways of calculating energy expenditure up to a BMI of at least 80. However answer D is incorrect if following the ASPEN guideline because that guideline emphasizes the kcal/kg method. The patient has class III obesity; therefore, ideal body weight would be used for the calculation,
making answer 3 incorrect because it uses adjusted body weight. Answer B is incorrect because the guideline already factors the 30% reduction in the energy calculation into the standard; therefore, if the energy expenditure were calculated and then multiplied by 70%, the effect would be to reduce the energy intake target to about 50% of expenditure.
Glucose and galactose gain access to enterocytes via
- Glucose-dependent insulinotropic polypeptide (GIP)
- Glucokinase
- Enterokinase
- Sodium-glucose transporter 1 (SGLT-1)
- Sodium-glucose transporter 1 (SGLT-1)
The presence of which of the following facilitates the absorption of sodium in the lumen of the small intestine
1. Glucose
- Potassium
3 .Vitamin D
- Protein
- Glucose
Which of the following is true about the net chemical reaction of glucose catabolism?
- Pyruvate is the final product.
- Oxygen is required for adenosine triphosphate (ATP) synthesis.
- Both water and carbon dioxide (CO ) are produced.
- CO is produced but water is not. 2
- Water is produced but CO is not
- Both water and carbon dioxide (CO ) are produced.
The correct answer is 3. Pyruvate is the final product of glycolysis. When pyruvate leaves the cytoplasm and enters the mitochondria, it loses CO2. The acetyl group then transfers to coenzyme A
(CoA) and forms acetyl-CoA. In aerobic conditions, pyruvate can be further oxidized during cell respiration. In anaerobic conditions, pyruvate can be broken down into lactate. Both metabolic
pathways can produce ATP. After all energy has been released from the glucose moiety, CO2 and water are the final products.
Which of the following incorrectly pairs a metabolic process with its site of occurrence?
- Glycolysis and cytosol
- Tricarboxylic acid (TCA) cycle and mitochondrial membrane
- ATP phosphorylation and cytosol and mitochondria
- Electron transport chain and mitochondrial membrane
- Oxidative decarboxylation of pyruvate and mitochondria
- Tricarboxylic acid (TCA) cycle and mitochondrial membrane
The correct answer is 2. The TCA cycle is the metabolic reaction of cell respiration, which occurs inside the eukaryotic mitochondrion (not on the mitochondrial membrane). Glycolysis occurs in the cytoplasm. ATP phosphorylation occurs both during glycolysis (in the cytoplasm) and the TCA cycle (in the mitochondrion). The electron transport chain is a carrier mechanism within the inner mitochondrion. The oxidative decarboxylation of pyruvate occurs in the mitochondrion.
Which of the following is least likely to occur during oxygen debt?
- Buildup of lactic acid
- Buildup of pyruvate
- Decrease in pH
- Increased fatigue
- Shortage of ATP
- Buildup of pyruvate
Under anaerobic conditions, pyruvate accepts a hydrogen atom from nicotinamide adenine dinucleotide plus hydrogen (NADH), forming nicotinamide adenine dinucleotide (NAD+) and lactic acid. At physiological pH, lactic acid is dissociated into lactate and
protons. Thus, the local pH decreases. Using this pathway, only 2 ATPs can be generated. A shortage of ATP is possible, leading to muscle fatigue.
What are some of the possible ramifications of activation of the enzyme, phospholipase A 2?
- Cyclooxygenase (COX)–dependent, eicosanoid-mediated inflammatory reactions
- Enzymatic degradation of resolvins and protectins
- Desaturation of linoleic acid within lipids
- Chylomicron maturation
- Cyclooxygenase (COX)–dependent, eicosanoid-mediated inflammatory reactions
Arachidonic acid (AA), common to membrane phospholipids, usually occupies the sn-2 position within lipids and is almost always found at this position within the important membrane phospholipid phosphatidylinositol. During membrane cell signaling events, a
possible outcome is the activation of phospholipase A2, the enzyme that acts on membrane phospholipids to release fatty acids from the sn-2 position. Release of AA sets in motion subsequent intracellular metabolic activity via the COX pathway that leads to the synthesis of the 2-series of prostaglandins, including prostaglandin E (PGE2), and thromboxanes, including thromboxane A2 .
How might propofol, when provided to patients within a 10% (w/v) lipid injectable emulsion (ILE), increase risk of hypertriglyceridemia?
- Propofol causes acute uptake of triglycerides (TGs) by the microvilli of the small intestine.
- Propofol is known to activate the release of TGs from adipose tissue.
- The increased presence of liposomes in the propofol ILE may interfere with chylomicron and pseudo-chylomicron metabolism.
- The presence of sedative in the ILE prevents phospholipid formation, which results in an
increased level of TGs in the blood.
- The increased presence of liposomes in the propofol ILE may interfere with chylomicron and pseudo-chylomicron metabolism.
Hypertriglyceridemia may be caused by interference with chylomicron and
pseudo-chylomicron metabolism as a result of the presence of liposomes within the ILE. Liposomes are formed during the emulsification process when parenteral ILE is produced. These liposomes are usually metabolized in a manner similar to the metabolism of pseudo-chylomicrons, but their presence may lead to the formation of a spherical bilayer of phospholipid and cholesterol known as lipoprotein-X. This lipoprotein inhibits both lipoprotein lipase and hepatic lipase enzymatic activity, and thus can interfere with the proper metabolism of the TGs that are part of the structure of chylomicrons and pseudo-chylomicrons. This interference and the accumulation of endogenous cholesterol can subsequently lead to an increase in circulating TGs and cholesterol. Because 10%
(w/v) ILE contains a greater number of liposomes relative to 20% (w/v) ILE as a result of the relative ratio of phospholipid emulsifier to oil, the former formulation places the patient at greater risk for hypertriglyceridemia
Which ionized form of a short-chain fatty acid (SCFA; up to 6 carbons in length) is thought to be the most important to colonic health and why?
- Myristate
- Caproate
- Butyrate
- Valerate
- Butyrate
SCFAs such as acetate, propionate, and butyrate are primarily produced in
the colon by bacteria and can serve as important energy sources for colonic tissue. Butyrate in particular is thought to modify inflammatory activity and promote colon health. For example, when applied directly to the colon, butyrate can attenuate the inflammatory activity seen in ulcerative
colitis. In addition, the fermentation of carbohydrate (fiber) and the production of SCFAs in the colon, especially butyrate production, appear to act as antitumorigenic stimuli.
Which of the following statements is true relating to hydrochloric acid (HCl) and protein digestion?
- HCl aids in the conversion of pepsin to pepsinogen.
- HCl denatures protein structures to make them more susceptible to enzymatic action.
- HCl is secreted by the parietal cells within the duodenum in response to dietary proteins.
- HCl’s release is stimulated by the hormone insulin.
- HCl denatures protein structures to make them more susceptible to enzymatic action
Denaturing protein structures, making them more susceptible B to enzymatic action, is a primary role of HCl. HCl plays several roles in protein digestion, including conversion of
the proenzyme pepsinogen to its active form pepsin. HCl is secreted by the parietal cells within the stomach, not the duodenum. HCl secretion is stimulated by gastrin, not insulin.
Proteins perform all the following physiological functions except:
- Provide a major source of energy.
- Maintain acid-base balance.
- Contribute to immune defense.
- Serve as a mode of transport for substances
- Provide a major source of energy
Carbohydrates and fats are the major energy source in the human diet. Protein is not preferentially used as a source of energy in health. Protein is used as the body’s primary
buffer to maintain acid-base balance. All cells of the immune system (ie, white blood cells,
macrophages, and so on) are made up of proteins. Proteins are the primary carriers for substances such as minerals, vitamins, and hormones.
Which of the following is an example of a patient condition anticipated to manifest with a severe systemic inflammatory response?
- Anorexia nervosa with body mass index (BMI) of 15
- Major depression with compromised dietary intake and 5% loss of body weight
- Homebound older adult with restricted access to food and 10% loss of body weight
- Thermal burn injury of second and third degrees covering 15% body surface area
- Thermal burn injury of second and third degrees covering 15% body surface area
The burn injury is significant and will be associated with D severe systemic inflammatory response. The diagnosis, clinical signs, physical examination data, and laboratory indicators for such a patient will support this conclusion. The other answers describe states of
starvation that are not likely to be associated with severe systemic inflammatory response.
A physician informs you that a patient has a serum albumin of 2.8 g/dL and prealbumin of 14 mg/dL and asks whether these laboratory findings mean the patient is malnourished. What is the most
appropriate response?
- The patient’s protein intake is inadequate, and the patient should receive prompt nutrition support.
- Together, these markers indicate that the patient has moderate protein-energy malnutrition.
- Consideration of medical history, clinical diagnosis, and laboratory signs of the inflammatory response would help you interpret these findings.
- For most hospitalized patients, albumin and prealbumin have excellent sensitivity and specificity to identify malnutrition.
- Consideration of medical history, clinical diagnosis, and laboratory signs of the inflammatory response would help you interpret these findings.
By themselves, these proteins should be interpreted with caution because they lack specificity and sensitivity as indicators of nutrition status. Both albumin and prealbumin may be reduced by the systemic response to injury, disease, or inflammation. Patients with low
albumin or prealbumin levels may or may not be malnourished. The patient’s medical history, clinical diagnosis, and laboratory signs of the inflammatory response can help clarify whether inflammation is present and whether the patient is malnourished.
Which of the following is one of the best validated screening indicators for malnutrition risk?
- Patient reports a nonvolitional weight loss.
- Patient reports following a low-carbohydrate, weight loss diet.
- Patient is 2 days status post laparoscopic cholecystectomy.
- Patient reports a recent flu-like febrile illness.
- Patient reports a nonvolitional weight loss.
Of the options provided, the only well-validated indicator to screen for
malnutrition risk is a nonvolitional weight loss. The other options might be noted in screening and assessment but are not themselves validated measures of malnutrition risk.
Which of the following is a benefit of EN compared with parenteral nutrition (PN) or no nutrition?
1.Maintenance of normal gallbladder function
2. Reduced gastrointestinal (GI) bacterial translocation
3. More efficient nutrient metabolism
4. All of the above
- All of the above
EN provides nutrients to the small intestine, stimulating D the release of
cholecystokinin, which helps maintain normal gallbladder function and reduce the risk of cholecystitis. Luminal nutrients provide GI structural support and help maintain the gut-associated and mucosa-associated lymphoid tissues vital to immune function. Immunoglobulin A (IgA), which is secreted within the GI tract in response to intraluminal nutrients, can prevent bacterial adherence and translocation. Nutrients from EN more closely mimic normal oral feeding, and undergo first-pass
metabolism, promoting more efficient nutrient utilization
High-protein hypocaloric EN feeding providing 65% to 70% of energy needs, as determined by indirect calorimetry (IC), is recommended for intensive care unit (ICU) patients with which of the following conditions?
- Malnutrition
- Obesity
- Liver failure
- Acute respiratory distress syndrome (ARDS)
- Obesity
Patients with malnutrition should receive more than 80% of their estimated nutrient needs within 48 to 72 hours of intubation. Delays in initiating and advancing EN result in greater energy and protein deficits, which may contribute to higher infection and mortality rates. Studies indicate obese patients benefit from low-calorie, high-protein feedings to minimize the metabolic complications of feeding, preserve lean body mass (LBM), and mobilize fat stores. In patients with ARDS, studies indicate no difference in outcomes between those receiving eucaloric feedings and those receiving trophic feedings
Risk factors for aspiration include all of the following except:
- Malnutrition
- Use of naso-/oro-feeding tube
- Bolus EN feeding
- Supine position
- Malnutrition
Although malnutrition may result in generalized weakness and contribute to swallow dysfunction, malnutrition by itself is not recognized as a risk factor for aspiration. Conditions that manipulate or affect the function of the lower esophageal sphincter, such as the
presence of a feeding tube in the esophagus, increase the risk of reflux and thus aspiration. Bolus feedings, which increase the volume of contents in the stomach, and the supine position also increase
the risk of reflux.
The use of 0.1N hydrochloric acid is most effective for clearing catheter occlusions due to precipitation of
A. calcium-phosphate
B. tobramycin
C. phenytoin
D. lipid residue
A. calcium-phosphate
thrombolyticsare NOT effective against every occlusion
The use of 0.1N hydrochloric acid has been reported effective in clearing catheters with crystalline occlusions because its acidic pH is favorable for calcium and phosphate solubility. Clinicians should be aware, however, that direct infusion of hydrochloric acid into the venous system can be associated with fever, phlebitis, and sepsis. For catheter occlusions due to precipitates associated with medications in the high pH range such as tobramycin and phenytoin, sodium bicarbonate 1 mEq/mL has been anecdotally reported to be effective. Seventy percent ethanol is the most effective solvent to dissolve lipid residue.
An alert and oriented adult patient is receiving a continuous infusion of a standard, fiber-containing EN formulation through an 8-Fr nasogastric (NG) tube. Drugs administered by bolus administration
through the side port of the tube are phenytoin suspension 400 mg daily and nizatidine 150 mg every 12 hours. The feeding tube becomes occluded and must be removed. A new tube is placed because a
long-term tube will not be considered until after a swallow study is completed 2½ weeks from now. Which of the following measures is most appropriate for preventing occlusion of the new tube?
- Replace the 8-Fr tube with an 18-Fr NG tube.
- Flush the feeding tube with 15 mL of water before and after administering each medication.
- Discontinue the fiber-containing enteral feeding formulation, and initiate feeding with a fiber-free formulation.
- Hold the feeding infusion for 2 hours before and after administering phenytoin.
- Flush the feeding tube with 15 mL of water before and after administering each medication.
The most likely cause of the feeding tube occlusion is B improper flushing technique. The tube should be flushed with a minimum of 15 mL of water before and after each medication, but 30 mL is commonly recommended and may be required to properly flush longer or larger tubes. Although the risk of occlusion is potentially greater with an
8-Fr small-bore tube than with an 18-Fr tube, the discomfort associated with such a large-bore tube would make it a poor choice for nasoenteral access in an alert patient, especially when needed for more than 2 weeks. Switching from a fiber-containing to a fiber-free EN formulation would have little influence on risk of tube occlusion. The fiber used in EN formulations has been processed to a degree that makes its viscosity similar to that of polymeric, fiber-free formulations. Holding the feeding infusion for 2 hours before and after phenytoin administration has been recommended as a method to enhance drug absorption; it would not be expected to influence tube occlusion.