Decreased surfactant production in the preterm lung is a problem because surfactant
dilates the bronchioles, decreasing airway resistance.
provides transportation for oxygen to enter the blood supply.
keeps the alveoli open during expiration.
causes increased permeability of the alveoli.
The Correct Answer is C
Choice A) dilates the bronchioles, decreasing airway resistance: This is not the correct function of surfactant.
Surfactant is a substance that reduces the surface tension of the fluid that lines the alveoli, which are the tiny air sacs in the lungs where gas exchange occurs. Surfactant does not affect the diameter of the bronchioles, which are the small airways that branch from the bronchi. Bronchodilation and bronchoconstriction are regulated by the autonomic nervous system and various mediators, such as histamine, epinephrine, and acetylcholine.
Choice B) provides transportation for oxygen to enter the blood supply: This is not the correct function of surfactant. Surfactant does not transport oxygen or any other gas. Oxygen diffuses from the alveoli into the capillaries, where it binds to hemoglobin in the red blood cells. The red blood cells then transport oxygen to the tissues via the blood circulation. Surfactant does not play a role in this process.
Choice C) keeps the alveoli open during expiration: This is the correct function of surfactant. Surfactant prevents the alveoli from collapsing during expiration by lowering the surface tension of the fluid that lines them. This allows for easier breathing and better gas exchange. Without enough surfactant, the alveoli tend to collapse and stick together, causing atelectasis, which is a condition where some or all of a lung collapses. Atelectasis can lead to hypoxia, respiratory distress, and infection.
Choice D) causes increased permeability of the alveoli: This is not the correct function of surfactant. Surfactant does not increase or decrease the permeability of the alveoli, which is the ability of substances to pass through them.
Permeability of the alveoli depends on several factors, such as pressure gradients, solubility, molecular size, and membrane thickness. Increased permeability of the alveoli can occur in conditions such as acute respiratory distress syndrome (ARDS), where fluid leaks into the alveolar space and impairs gas exchange. Surfactant does not cause this condition, but it can be affected by it.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Choice a) D5W intravenously is incorrect because this is not the preferred method of feeding for a hypoglycemic infant. D5W stands for dextrose 5% in water, which is a solution that contains glucose and water. It can be used to treat hypoglycemia by providing a source of energy and fluid to the infant. However, it has several disadvantages, such as requiring an invasive procedure, increasing the risk of infection, causing fluid overload or electrolyte imbalance, and stimulating insulin secretion, which can lead to rebound hypoglycemia. Therefore, D5W intravenously should be reserved for severe cases of hypoglycemia that do not respond to oral or enteral feeding.
Choice b) Formula via nasogastric tube is incorrect because this is not the first-line option of feeding for a hypoglycemic infant. Formula is an artificial substitute for breast milk that contains nutrients and calories to support the infant's growth and development. It can be given via nasogastric tube, which is a tube that passes through the nose and into the stomach, when the infant cannot suck or swallow effectively. However, formula has several disadvantages, such as being less digestible, less immunogenic, and less adaptable than breast milk, as well as increasing the risk of necrotizing enterocolitis, allergy, or infection. Therefore, formula via nasogastric tube should be used only when breast milk is unavailable or contraindicated.
Choice c) Breast milk is correct because this is the best and most recommended type of feeding for a hypoglycemic infant. Breast milk is the natural and optimal food for infants that contains all the nutrients and antibodies they need to grow and thrive. It can be given directly from the breast or expressed and fed by bottle or cup. Breast milk has several advantages, such as being easily digestible, enhancing immune function, promoting bonding, and adjusting to the infant's needs. Breast milk also contains lactose, which is a natural sugar that can raise the blood glucose level of the infant without causing a spike in insulin secretion. Therefore, breast milk should be offered to the hypoglycemic infant as soon as possible after birth and at regular intervals thereafter.
Choice d) Glucose water in a bottle is incorrect because this is not an appropriate type of feeding for a hypoglycemic infant. Glucose water is a solution that contains glucose and water. It can be given by bottle or cup to provide a quick source of energy to the infant. However, it has several disadvantages, such as providing no other nutrients or calories, interfering with breastfeeding, causing diarrhea or dehydration, and stimulating insulin secretion, which can lead to rebound hypoglycemia. Therefore, glucose water in a bottle should be avoided or used sparingly for mild cases of hypoglycemia that do not respond to breast milk.
Correct Answer is B
Explanation
Choice A) Wrap the cord loosely with a sterile towel saturated with warm normal saline: This is not an appropriate action because it does not relieve the compression of the cord, which can cause fetal hypoxia and acidosis. The cord should be kept moist, but not wrapped around anything.
Choice B) Place a sterile gloved hand into the vagina and hold the presenting part off the cord while calling for assistance: This is the correct action because it prevents further descent of the fetus and reduces the pressure on the cord, which can improve fetal oxygenation and blood flow. The nurse should also elevate the woman's hips and place her in a knee-chest or Trendelenburg position to reduce gravity. The nurse should call for immediate assistance and prepare for an emergency cesarean section.
Choice C) Increase the IV drip rate: This is not an appropriate action because it does not address the cause of the variable decelerations, which is cord compression. Increasing the IV fluid may cause fluid overload and worsen maternal and fetal outcomes.
Choice D) Administer oxygen to the woman via mask at 8 to 10 L/minute: This is not an appropriate action because it does not relieve the cord compression, which is the main threat to fetal well-being. Oxygen administration may be helpful in some cases of fetal distress, but it is not sufficient in this situation.
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