HEAD-OF-BED ELEVATION AND TRACHEAL PEPSIN
Ventilator-associated pneumonia (VAP) is one of the most important healthcare-associated infections in hospitalized patients. Bundles of interventions are applied in adult and pediatric intensive care units to try to prevent episodes of VAP, and the evidence base for these interventions has grown in recent years. In neonates, interventions to prevent VAP are largely modeled on those for older patients, although we have little evidence to show whether this makes sense.
For example, a key element of VAP bundles is to elevate the head of the bed of the patient on a ventilator to a 30º to 45º angle. The rationale for this intervention is to reduce the patient's risk for aspirating bacterially contaminated gastrointestinal contents or oropharyngeal and nasopharyngeal secretions into the airway. Practically speaking, we can elevate the head of a neonate's bed (head end of the incubator mattress) only about 15º in the neonatal intensive care unit (NICU). In ventilated neonates, in whom uncuffed endotracheal tubes are used, is 15º enough to prevent microaspiration of stomach contents?
A study conducted at Wheaton Franciscan Healthcare–St. Joseph Hospital in Milwaukee, Wisconsin, measured the gastric enzyme pepsin, a biomarker for microaspiration, to determine whether the amount of tracheal pepsin changed with the angle of elevation of the head of bed. Serial tracheal samples (at 3, 7, 14, 21, and 28 days of ventilation) were obtained from intubated, ventilated very low-birth-weight infants (mean birth weight = 798 g). The presence of tracheal pepsin was determined by Western blot analysis using a specific antihuman pepsin antibody.
They found that early elevation of the head of bed was associated with a lower rate of tracheal pepsin in the neonates. Tracheal pepsin was detected in 35 of the 66 ventilated neonates (53%). Neonates whose head elevation was in the upper quartile (≥14º) during the first sampling time (day 3) were less likely (P = .0013) to have tracheal pepsin compared with neonates whose head elevation was in the lowest quartile (≤8º). So, even though we cannot elevate the head of the bed as high as 30º to 45º, elevation to 15º can reduce microaspiration of stomach contents. Whether this reduces rates of neonatal VAP will require further study.
1. Metheny NA, Chang YH, Ye JS, et al. Pepsin as a marker for pulmonary aspiration. Am J Crit Care. 2002;11:150–154.
2. Garland JS, Alex CP, Johnston N, Yan JC, Werlin SL. Association between tracheal pepsin, a reliable marker of gastric aspiration, and head of bed elevation among ventilated neonates. J Neonatal Perinat Med. 2014;7:185–192.
ANTIMICROBIAL-TREATED UMBILICAL CATHETERS
Another preventable hospital-associated infection in the neonatal population is central line–associated bloodstream infection (CLABSI), which can occur during the use of any type of central venous catheter, including umbilical venous catheters (UVCs). Recently, UVCs impregnated with silver zeolite (the patented silver compound AgION) have become available and are recommended by the Society for Healthcare Research and Epidemiology for use in preterm infants to prevent CLABSI.1
AgION is an inorganic compound that inhibits microbial growth by releasing active silver ions. AgION-coated UVCs were shown in a recent study2 to effectively reduce CLABSI rates in preterm infants. A study in 86 infants with gestational age less than 30 weeks were randomized to receive either an AgION-treated or nontreated polyurethane UVCs. In the AgION group, 2% of infants developed CLABSI compared with 22% of the infants in the control group (P = .005). AgION catheters were well tolerated without any evidence of silver toxicity.
The recommendation by Society for Healthcare Research and Epidemiology was part of “A Compendium of Strategies to Prevent Healthcare-Associated Infections in Acute Care Hospitals: 2014 Updates.” In addition to CLABSI, these evidence-based recommendations cover major healthcare-associated infections including catheter-associated urinary tract infection, surgical site infection, ventilator-associated pneumonia, and methicillin-resistant Staphylococcus aureus. The prevention strategies pertain to all patients in acute care hospitals, including neonates, children, and adults.
1. Marschall J, Mermel LA, Fakih M, et al. Strategies to prevent central line–associated bloodstream infections in acute care hospitals: 2014 update. Infect Control Hosp Epidemiol. 2014;35(suppl 2):S89–S107.
2. Bertini G, Elia S, Ceciarini F, Dani C. Reduction of catheter-related bloodstream infections in preterm infants by the use of catheters with the AgION antimicrobial system. Early Hum Dev. 2013;89:21–25.
TRANSCUTANEOUS BILIRUBINOMETRY AFTER PHOTOTHERAPY
Transcutaneous bilirubin (TcB) meters are not typically used during phototherapy (unless an area of skin is covered with a patch), because the blanching of the exposed skin caused by phototherapy can underestimate the total serum bilirubin (TSB) level to an unknown degree. For the same reason, TcB readings are not generally used for postphototherapy follow-up of an infant's bilirubin level, even though it would be a more convenient way to assess for rebound hyperbilirubinemia than having to draw blood from the infant.
A team of investigators set out to find out whether TcB values could reliably be used after phototherapy for neonatal jaundice.1 They compared simultaneous TcB readings and TSB values in 86 (47 preterm and 39 term) infants who were receiving in-hospital phototherapy. They collected a total of 189 parallel measurements, using the JM-103 transcutaneous bilirubinometer. They aimed to determine whether TcB readings could safely be used to decide whether phototherapy should be restarted or not, without drawing a TSB.
They found that the mean TcB-TSB difference before phototherapy was −0.6 mg/dL. For the first 8 hours after phototherapy was discontinued, mean TcB levels were lower than TSB levels by an average of 2.4 mg/dL. After 8 hours, the mean difference between TcB and TSB gradually returned to pretreatment values (−1.8 mg/dL at 8-16 hours, −1.1 mg/dL at 16-24 hours, and −0.8 mg/dL after 24 hours).
These TcB levels underestimated TSB slightly, in a predictable, time-dependent manner. To determine whether TcB levels could safely be used to decide on the need for restarting phototherapy, they used the TcB-TSB differences and the infant's individual phototherapy threshold (the level at which phototherapy would be restarted) at different time periods. Their analysis showed that if the TcB level measured at 8 hours postphototherapy was 7.3 mg/dL below the infant's threshold for treatment, it was safe to forego drawing a confirmatory TSB. After 8 hours, a TcB level that was 5.0 mg/dL or more lower than the treatment threshold suggested that no TSB was necessary.
1. Grabenhenrich J, Grabenhenrich L, Bührer C, Berns M. Transcutaneous bilirubin after phototherapy in term and preterm infants. Pediatrics. 2014;134:e1324–e1329.
CHEMICAL EXPOSURE IN THE NICU
For some years now, concern about the exposure of still-developing infants to chemicals has been framed in terms of risks for endocrine disruption, but this is a vague, long-term outcome that has not been sufficiently concerning to prompt widespread action.
A new study from the Johns Hopkins Bloomberg School of Public Health, Risk Sciences and Public Policy Institute1 suggests that the risks associated with exposure to harmful chemicals are far more immediate. Investigators assessed the types and magnitudes of nonendocrine toxic risks to neonates associated with medical device–related exposures to di(2-ethylhexyl)phthalate (DEHP). Using data about the magnitudes of exposure of neonates to DEHP from polyvinyl chloride devices and dose-response thresholds for DEHP toxicities, investigators calculated that the total daily exposure to DEHP for infants in the NICU can reach 16 mg/kg per day from such sources as intravenous tubing, endotracheal tubes, and blood transfusion tubing. How toxic is this level of DEHP? It is 4000 times higher than desired to prevent male reproductive tract toxicity, and 160 000 times higher than desired to prevent hepatic damage. Although this study does not prove that DEHP exposure harms infants, such exposure is known to be proinflammatory, and many of the comorbidities and complications of prematurity experienced by the neonatal population are inflammatory in nature. For example, the toxicity of endotracheal tubes could be a factor in the common finding that preterm infants who have been on mechanical ventilation have worse outcomes. The investigators conclude that DEHP exposures during neonatal intensive care are much higher than estimated safe limits.
In consideration of the precautionary principle, the implications of this study are clear. Where alternatives are available, we should immediately replace all DEHP-containing products in the NICU with DEHP-free products. We should also seek to eliminate other sources of phthalates (vinyl flooring, paint, ventilators, incubators; soaps, lotions, and cosmetics used by staff and visitors; and soaps and lotions used for baby care) wherever possible, and encourage, through purchasing and advocacy, the development and use of products for neonatal care that are free of harmful chemicals.
1. Mallow EB, Fox MA. Phthalates and critically ill neonates: device-related exposures and non-endocrine toxic risks. J Perinatol. 2014;34(12):892–897.
FEEDING BABIES ON NASAL CONTINUOUS POSITIVE AIRWAY PRESSURE
For the most part, infants receiving nasal continuous positive airway pressure (NCPAP) therapy receive tube feedings, even if they are mature enough for oral feeding. Feeding the infant on NCPAP is not contraindicated,1 but it is often not attempted because of concerns for aspiration owing to gastric distention, or fears that an infant on NCPAP is not stable enough for oral feeding. Very little research has been done to assess whether infants on NCPAP can safely and effectively breastfeed or bottle feed.
In a recent study, the safety and efficacy of oral feeding were examined in infants (37-42 weeks' postmenstrual age) with bronchopulmonary dysplasia (BPD) on NCPAP.2 Data from 26 infants with BPD on NCPAP who were orally fed were compared with those from 27 similar infants who were gavage fed. Infants in the NCPAP-oral fed group were on full oral feedings 17 days earlier than the NCPAP-gavage-fed group. No infant in either group experienced clinically significant aspiration pneumonia during oral feeding while on NCPAP. The investigators concluded that controlled introduction of oral feedings in infants with BPD who are on NCPAP is safe and can accelerate the acquisition of full oral feedings, an important milestone toward discharge from the NICU.
1. Bonner KM, Mainous RO. The nursing care of the infant receiving bubble CPAP therapy. Adv Neonatal Care. 2008;8:78–95.
Hanin M, Nuthakki S, Malkar MB, Jadcheria SR. Safety and efficacy of oral feeding in infants with BPD on nasal CPAP [published online ahead of print November 8, 2014]. Dysphagia.
FROM NICU TO THE MOON
NICU nurses know that to do their jobs; it helps to be a little bit crafty, as in “arts and crafts.” Many of our patients stay with us for weeks or months, and their cribs and incubators are progressively decorated with name signs, pictures, and cards made by parents, siblings, and yes, even nurses, to celebrate birthdays, milestones, and holidays. Fortunately, every NICU has a few good photographers who can take really cute premie pictures for Mother's Day and Father's Day, embellished with perfect, unsmudged, 5-toe footprints.
The nurses at Children's Healthcare of Atlanta at Scottish Rite recently blended their artistic skills in photography and drawing in a series of adorable photographs of the babies in their unit. They depicted their tiny patients dreaming about their futures as ballerinas, Olympic athletes, and astronauts by editing photos of sleeping babies with colorful drawings. The results can be seen in an online blog by NICU Clinical Educator Jessica Wright, “From NICU to the Moon” at http://www.dedicatedtoallbetter.org/nicu-moon/.