This case study addresses nutrition, feeding, and lactation issues in very low birth weight infants with chronic lung disease. The focus is on the time period before and after hospital discharge.
Participants should be able to satisfy the following learning objectives:
Amy is an ex-25-week, 686-gram Caucasian female with chronic lung disease born March 6, 1999 to a 25 year-old gravida 2 para 1 woman. Amy’s mother and father have been married for 7 years and have a 4-year-old son. They have a very supportive family with no significant past medical history. Amy’s Apgar scores were 6 at one minute and 7 at five minutes.
Amy was intubated immediately after birth and given positive pressure ventilation due to prematurity. She was placed on the high frequency oscillator on March 22 because of ventilator instability (her FiO2 was increasing and her saturations were decreasing). Her respiratory status then stabilized, and Amy was placed back on conventional mechanical ventilation on March 30. She was extubated on May 6 and placed on 40% oxygen via nasal cannula. She had to have several doses of lasix administered throughout her hospital course in an attempt to improve her pulmonary status, and was finally placed on chronic diuretics at the end of June to try to decrease her oxygen requirement. She was discharged on 15cc/minute flow oxygen.
Gradually, enteral feeds were advanced to 1 cc every 4 hours on March 10 and then to 1 cc every hour on March 12. On March 13, Amy developed hyperglycemia (glucose = 211), increased ventilatory requirements, and increased abdominal girth. A gastrointestinal ileus was suspected, so enteral feeds were held. In addition, the dextrose concentration in Amy's parenteral nutrition was decreased to 6%. Gradually, the parenteral dextrose concentration was increased and Amy reached full parenteral nutrition support on March 17. Trophic feeds were reinitiated on March 18 at 0.5 cc of breastmilk every hour and were slowly increased to 3 cc every hour on April 10. Approximately 3 cc of enteral feeds per hour will meet 50% of Amy’s total fluid needs; therefore Amy had reached half-feeds via enteral nutrition at 3 cc per hour.
Similac Human Milk Fortifier was added to the breastmilk on April 10 when Amy reached half feeds. In addition, the team began to taper Amy’s parenteral nutrition support at this point. On April 14, Amy reached full enteral feeds (6 cc every hour of breastmilk plus Similac Human Milk Fortifier), and parenteral nutrition support was subsequently discontinued.
MCT oil was added to feeds to increase the energy density to 27 kcal/oz. A vitamin supplement and iron supplement were added on April 27.
Amy began nippling some of her enteral feeds (about 15% of total feeds) through a bottle nipple on May 8. She still tired with feeding and experienced increased respiratory rate, increased FiO2, and choking as feedings progressed, so remaining volumes from each feeding were delivered through tube feedings. On May 14 Amy breastfed at the breast for the first time. By May 28, Amy was nippling 26% of her feeds, and going to breast at least once a day. She continued to experience increased respiratory rate, FiO2 and choking with feedings. She did better with feedings at the breast than those delivered by bottle. However, by June 5, Amy was still only able to nipple ~25% of feeds due to respiratory distress and choking. At this time, Amy was approaching discharge status, and the only remaining medical concern was her inability to nipple all of her feeds. Amy’s parents were reluctant to participate in a home tube feeding program, so plans were made to discharge her only when she was able to nipple 100% of feeds. MCT oil was discontinued on June 14, which decreased the energy density of her feeds to 24 kcal/ounce.
A Physical Therapy evaluation on June 15 revealed that Amy was able to take approximately 50% of her feeds by nipple. She had occasional spontaneous mild apneic episodes associated with her feedings. She would stop sucking every 3-4 sucks to pant and catch her breath. She also exhibited increased work of breathing and increased respiratory rate with her feeds that would interfere with her ability to suck continuously. It was determined that she simply lacked the respiratory support to continue sucking. The conclusions to the feeding observation were that Amy was ready to nipple from a coordination/maturation standpoint but lacked the respiratory support to feed adequately.
Date |
Weight (g) |
Length (cm) |
OFC (cm) |
| 3/6/99 | 686 | ||
| 3/23/99 | 892 | ||
| 3/29/99 | 964 | ||
| 4/5 | 1090 | ||
| 4/12 | 1066 | 34.3 | 26 |
| 4/21 | 1142 | 34.5 | |
| 4/27 | 1252 | 37.7 | |
| 5/11 | 1664 | 39.2 | 29.5 |
| 5/18 | 1918 | 42.5 | |
| 5/26 | 2205 | 31 | |
| 6/7 | 2578 | 44.1 | |
| 6/14 | 2871 | 44.5 | 33.75 |
| 6/25 | 3130 | 46.9 | |
| 6/28 | 3230 | 47.2 | 35.5 |
By June 22, Amy was still nippling only 30-68% of feeds. Her parents were anxious to bring her home, so they reluctantly agreed to learn to tube feed Amy at home. Therefore preparation for discharge to home included partial tube feedings. Amy’s nippling abilities dramatically increased during the last week of her hospitalization, and she was discharged home on July 2 nippling all of her feeds, however still experiencing some increased respiratory rate and FiO2 as well as some (although less frequent) choking with feeds. Tube feeding equipment was provided to the family, in case it would be needed. The family insurance coverage did not cover the cost of the pump rental at home. The family would need to pay $95 out-of-pocket each month for the pump rental.
At hospital discharge Amy was scheduled for follow up at a pediatric pulmonary clinic in one month. One reason for the pulmonary clinic visit was to assess feeding concerns and the possibility of gastrostomy tube placement if compromised respiratory status continued to inhibit Amy’s ability to feed.
Breastmilk at the breast as much as possible. Delivered by bottle or through nasogastric tube: expressed breastmilk with added formula to concentrate feedings to 24 kcal per ounce or standard infant formula concentrated to 24 kcal/ounce on demand for a minimum of 130 cc/kg/day and a maximum of 160 cc/kg/day. Her parents were provided with tube feeding equipment at home in case it was needed to assist Amy in achieving adequate nutritional intake.
A home health care organization would visit the family at their home daily for 1.5-2 hours per day for the first 2 weeks following discharge. Amy was also discharged home on home oxygen with spot oximeter checks. Her follow-up appointments included her Primary Care Physician the first week following discharge, a pediatric pulmonary clinic visit one month after discharge, and high-risk infant follow-up clinic 4 months following discharge.
The first days at home were difficult for Amy and her family in terms of breastfeeding, but within a month the outlook was improving. A follow-up phone call by the hospital-based lactation consultant on July 5 found that Amy was not breastfeeding at the breast at home. Amy’s mother wanted to breastfeed and was frustrated with not being able to overcome the challenges of nippling at the breast for the first days at home. The lactation consultant continued to follow the family with phone calls, and by August 5 Amy was nursing at the breast 2 or 3 times each day.
Amy and her mother attended her one-month follow-up visit at the pediatric pulmonary clinic to discuss any questions or concerns and to determine her level of improvement. Amy’s mother was still expressing her breastmilk, and Amy was still receiving breastmilk fortified with Similac powder to ~24 kcal/oz. At this visit, Amy’s mother revealed that Amy had been feeding fairly well, with minimal issues. She had a small amount of emesis following feeds, however it was not significant and didn’t appear to upset Amy. She still required supplemental oxygen, especially with feeding and other activities. She was feeding every 3-4 hours and taking 3-4 ounces per feed. It took approximately 60 minutes to finish each bottle. In addition Amy was nursing at the breast 2 to 3 times a day.
Amy’s mom expressed the desire to feed Amy exclusive breastmilk at this time for several reasons. She wanted to focus on nursing at the breast, and did not want to have to offer Amy bottles at each feeding. She was spending considerable time expressing her milk with either an electric or a manual pump at least 5-6 times per day for 15-25 minutes at each time. It also took time to clean the pump, bottles and nipples and to prepare bottles for each feeding.
Occasionally, extended family members and friends helped with chores and child care, but most of the time, Amy’s mom was home alone with both children during the day.
What was Amy’s corrected age at discharge? What are the percentiles for each of Amy’s discharge anthropometric measurements based on her corrected age? What was Amy’s corrected age at her one-month follow-up visit? Based on her follow-up physical exam, what are the percentiles for each of her measurements? What conclusions can you make based on your findings? Plot each of these measurements on the WHO growth chart.
| Corrected Age at discharge: 2 weeks | Corrected Age at one-month follow-up: 6 weeks |
Based on these measurements, it appears that Amy is experiencing catch-up growth. She has crossed percentiles on the weight gain chart; weight is at the 50th-75th percentile. In addition, she has crossed percentiles on her growth chart and is now at the 50th percentile. Her head growth has remained constant, in the same growth chart channel. Her weight gain and growth status indicate that Amy is receiving an adequate nutritional intake to support the increased work of breathing as well as growth and weight gain.
Which factors that occurred early in Amy’s life put her at risk for osteopenia?
The primary risk factor for Amy was the fact that she received her nutrients exclusively via total parenteral nutrition (TPN) for greater than 3 weeks. TPN does not supply sufficient levels of calcium and phosphorus for adequate bone mineralization in preterm infants because in high concentrations these minerals will precipitate in the TPN solution. Calcium and phosphorus deficiency can result in osteopenia and is a major contributor to rickets and fractures in preterm infants. In addition, Amy received several doses of Lasix, a calcium-wasting diuretic, and a chronic course of diuretics after discharge as treatment for her chronic lung disease.
What are interventions in the NICU that could help decrease Amy’s risk of developing osteopenia?
As soon as Amy is able to take at least one-half of her nutrients enterally, it is important to provide her with an adequate source of calcium, phosphorus, and vitamin D to ensure adequate bone mineralization. Breastmilk has insufficient amounts of vitamins D and K, folic acid, iron, calcium and phosphorus to meet the needs of very low birth weight (VLBW) infants. Therefore, breastmilk is fortified with a human milk fortifier such as Similac Human Milk Fortifier or Enfamil HMF, which should bring the content of vitamins and minerals up to adequate amounts for preterm infants. In addition, because Amy may not be able to consume the volume of fortified breastmilk needed to obtain optimal nutritional status, it is often necessary to provide a low-birth-weight vitamin supplement. Once Amy reaches approximately 2.5 kg, preterm human milk fortifier should be discontinued due to potential vitamin A and D toxicity.
When should a multivitamin be recommended?
VLBW infants have increased vitamin and mineral needs during the first weeks and months of life to promote optimal growth and development, especially of the lungs and bones. It is unclear exactly what level of vitamins and minerals are needed or how long these increased needs persist. The National Research Council has established standards for vitamin and mineral intakes. Because breastmilk does not provide adequate amounts of vitamin D, vitamin K, folic acid, calcium, phosphorus, and iron, a multivitamin should be provided to all exclusively breastfed VLBW infants. If a formula-fed infant is taking at least 32 ounces of formula per day, the infant should be obtaining adequate amounts of vitamins and minerals. If the infant is only able to take 16-32 ounces per day, one-half of a multivitamin should be provided per day. If the infant takes less than 16 ounces of formula per day, one full multivitamin should be provided per day to meet recommended daily intakes of vitamins and minerals.
Calculate Amy’s average weight gain from March 29 to April 12. Is this appropriate? Why or why not?
During this period, Amy was gaining an average of 7 grams per day. This is lower than the recommended rate for preterm infants (15 g/kg/day). Possible reasons for this poor growth include inadequate energy intake, respiratory distress, infections, or inappropriate isolette temperature causing more energy to be devoted to maintaining body temperature. This weight gain pattern may also reflect changes in fluid status and delayed diuresis. Weight gain during the period from March 6 through March 23 was 206 grams during a time when early diuresis might be expected to occur.
Calculate Amy’s average weight gain from discharge to her follow-up visit. Is this appropriate? Why or why not?
Amy’s average weight gain from discharge to follow-up was approximately 40 grams/day. Her rate of growth averaged 6.8 cm/month (2.2 mm/day). Goal rates of gaining and growing for a preterm infant of Amy’s age are 25-35 g/day and 3 cm/month (1 mm/day). Therefore, Amy is exhibiting catch-up growth, which is defined as rates of weight gain and growth greater than expected for term infants of the same corrected age.
How many ounces of formula was Amy taking per day at her follow-up visit? How many kilocalories is this? How many kilocalories per kilogram is this? Is this appropriate? Why or why not?
Since Amy consumes approximately 4 ounces of formula every 4 hours, she takes in a total of 24 ounces of formula per day. Her formula is breastmilk plus Similac powder concentrated to 24 kcal/ounce. Therefore, each day, she consumes approximately 576 kcal, or 125 kcal/kg. The expected intake for an infant with Chronic Lung Disease ranges from 120 kcal/kg to 180 kcal/kg. Therefore, based on Amy’s current growth rate, she is consuming adequate energy for lung growth and development as well as catch-up growth.
At what age did Amy begin nippling her feeds? What age would you expect preterm infants to begin nippling feeds? Why?
Amy was 34 weeks corrected gestational age when she began nippling her feeds. Non-nutritive sucking, characterized by short, rapid bursts of 2 sucks per second and not associated with swallowing, begins around 18-24 weeks gestation. True nutritive sucking, characterized by a pattern of short sucking bursts followed by swallowing 1-4 times per burst, does not begin until 32-36 weeks gestation. Preterm infants may begin to nipple some feeds by 34 to 36 weeks. Developmental limitations and physical conditions must be taken into account when determining nippling expectations.
The infant’s physical condition greatly influences the timing of initiation of and advancement to complete nipple feeding. Physical condition variables that influence feeding outcomes include duration of assisted ventilation, duration of supplemental oxygen, and weight. Infants requiring mechanical ventilation are generally tube fed during their first weeks or months of life. They often experience delayed initiation of nipple feedings. Infants requiring supplemental oxygen may tire during nipple feeding and may not be able to nipple 100% of feeds. Other respiratory difficulties, including irregular breathing, apneic spells, and bradycardia may interfere with feeding by causing the infant to choke and/or tire easily. These infants may develop oral aversive behaviors.
Why was it necessary to add Similac Human Milk Fortifier and MCT oil to Amy’s feeds?
Energy needs of infants with Chronic Lung Disease range from 120 kcal/kg to 180 kcal/kg, depending on the severity of illness. Until the infant reaches 2.5-3.0 kg body weight, a premature formula (or a human milk fortifier added to breastmilk) is recommended to meet increased energy, protein, vitamins, calcium, and phosphorus. In Amy’s case, Similac Human Milk Fortifier was added to breastmilk to increase the energy density to 24 kcal/ounce and to provide the extra protein, vitamins and minerals that she needed for lung repair and growth and to ensure bone mineralization. Often, however, breastmilk plus fortifier does not provide enough energy to support a recommended growth rate of 15 g/kg/day.
Modular components may be added to increase energy density above 24 kcal/ounce. MCT was added to increase energy intake because medium chain triglycerides are more readily absorbed and may be used when immaturity or GI conditions impair digestion and absorption of long chain fatty acids.
How would you respond to Amy’s mother when she expresses interest in exclusively breastfeeding Amy at the breast?
There are two primary concerns regarding placing Amy exclusively at the breast to feed. First, many very low birth weight infants are not successful in transferring the milk from the breast primarily due to feeding limitations of the infant. Breastfeeding at the breast requires different feeding skills than bottle feeding. Since Amy has already demonstrated feeding difficulties and respiratory changes with feeding she may not be able to obtain an adequate volume of breastmilk to sustain growth through breastfeeding alone until her respiratory condition and/or feeding capabilities improve.
The second concern is that breastmilk has a lower energy density (20 kcal/oz) than the fortified breastmilk that Amy is receiving in her bottle (24 kcal/oz). Therefore, Amy would have to consume a greater volume of breastmilk at the breast than she would have to with fortified breastmilk to meet her energy needs. It is likely that Amy’s growth velocity would slow down as a result of a suboptimal energy intake. However, some infants can tolerate some daily feedings at 20 kcal/oz if they receive more energy dense feedings at other times in the day.
Because Amy was showing adequate growth it would be reasonable to begin to increase the number of times that Amy is put to breast each day. The remainder of her feeds could be delivered 3 to 4 times a day with a bottle and 24 kcal/ounce feedings. The increased frequency of nippling would help enhance Amy’s mother’s milk supply and might provide pleasurable times for Amy and her mother. Amy’s mother may benefit from ongoing consultation with a lactation consultant. It is critical to closely monitor Amy’s weight trends during this transition period.