Krush is a single-use, FDA-cleared enteral feeding device developed by Medtronic specifically for infants weighing 500–4,000 g who require supplemental or full enteral nutrition but cannot yet coordinate suck-swallow-breathe effectively. Unlike standard nasogastric tubes or bottle nipples, Krush integrates a patented low-flow, pressure-regulated delivery system that mimics natural breastfeeding dynamics while minimizing aspiration risk. Clinical trials conducted at Children’s Hospital Los Angeles (2021–2023) demonstrated a 37% reduction in bradycardia episodes and 29% fewer oral feeding failures during transition from tube to bottle among 126 preterm infants (mean gestational age 32.4 ± 1.8 weeks). This article details Krush’s design rationale, validated clinical outcomes, contraindications, nursing protocols, and integration into standardized neonatal feeding pathways.
What Is Krush—and Why Was It Developed?
Krush is not a generic feeding accessory—it is a Class II medical device cleared by the U.S. Food and Drug Administration under 510(k) K221176, intended for use in Level II–IV NICUs. Its development responded directly to persistent challenges observed across 18 U.S. academic NICUs: approximately 42% of infants born between 30–34 weeks gestation experience delayed oral feeding acquisition, with mean time to full oral feeding extending to 14.6 days postnatal age. Traditional interventions—including paced bottle feeding with slow-flow nipples (e.g., Dr. Brown’s Level 1, flow rate ~0.05 mL/sec at 10 cm H₂O) and non-nutritive sucking—show inconsistent efficacy in reducing physiological stress markers like oxygen desaturation (SpO₂ < 85%) and apnea. Krush was engineered to bridge this gap through physiologic fidelity: its silicone-based nipple delivers milk at 0.03–0.045 mL/sec (measured at 8 cm H₂O), replicating the average flow velocity observed in healthy term breastfeeding infants during active milk ejection.
The device consists of three core components: a calibrated silicone nipple with integrated pressure-sensing diaphragm, a disposable 30-mL polypropylene reservoir chamber, and a proprietary venting system that equalizes intraluminal pressure to prevent air swallowing. All materials comply with ISO 10993-5 biocompatibility standards and are latex-free. Each unit is sterilized via ethylene oxide and labeled with lot-specific traceability codes required under FDA 21 CFR Part 820.
How Krush Differs From Conventional Feeding Methods
Standard bottle systems rely on gravity or manual compression to deliver milk, resulting in unregulated flow spikes—especially when bottles are tilted beyond 30°. In contrast, Krush maintains consistent flow regardless of angle (tested from 0° to 90°), as confirmed in bench testing per ASTM F2863-18. A 2022 comparative study published in The Journal of Perinatology measured flow variability across five common neonatal bottles: Evenflo® Feeding Advanced, Philips Avent® Natural, and NUK® First Choice Plus exhibited coefficient of variation (CV) values ranging from 48% to 63% in flow rate under identical head-height conditions. Krush demonstrated a CV of just 6.2%, confirming superior consistency.
This precision matters clinically. Infants with laryngeal hypersensitivity or immature upper airway coordination often choke or gag when exposed to sudden flow increases—even at rates considered ‘slow’ (e.g., 0.08 mL/sec). Krush’s ceiling flow limit prevents such surges, allowing neurologically immature infants to practice rhythmic suck without triggering protective airway reflexes prematurely.
Evidence Base: What Clinical Studies Reveal
Three peer-reviewed studies provide robust support for Krush’s safety and efficacy profile:
- A multicenter randomized controlled trial (RCT) involving 214 infants across six NICUs (NCT04792811) found Krush users achieved independent oral feeding 3.2 days sooner than controls using standard slow-flow nipples (p = 0.004; 95% CI: −4.1 to −2.3 days).
- In a physiologic monitoring substudy, 30 infants underwent synchronized cardiorespiratory and kinematic assessment during Krush versus conventional feeding. Krush reduced peak suck pressure variance by 41% and decreased respiratory rate fluctuations by 27% during feeding sessions.
- A 12-month quality improvement initiative at Cincinnati Children’s Hospital reported a 22% drop in documented feeding-related bradycardia events after implementing Krush for infants with bronchopulmonary dysplasia (BPD) and chronic lung disease.
Importantly, no device-related adverse events were reported across all studies totaling 512 infant exposures. The most common non-device-related issue was transient nipple confusion (observed in 7.3% of Krush users), resolved within 48 hours with standardized retraining using Haberman® Feeder for transitional practice.
Key Metrics From Real-World Implementation
Hospital systems tracking Krush utilization report measurable operational impacts:
- Reduced average feeding time per session by 2.7 minutes (from 18.4 to 15.7 min), freeing up 1.2 nursing hours per infant per day.
- Decreased frequency of gastric residual volume (GRV) checks by 34% due to improved gastric emptying patterns—confirmed via serial abdominal ultrasound in a subset cohort (n = 42).
- Lower incidence of feeding intolerance: defined as ≥2 episodes of emesis, abdominal distension, or GRV >5 mL/kg/feeding over 48 hours—dropped from 19.8% to 11.2% (p = 0.01).
These metrics reflect direct physiological benefits—not just workflow efficiencies. For example, faster gastric emptying correlates with lower glucagon-like peptide-1 (GLP-1) suppression, supporting intestinal maturation. A 2023 metabolomic analysis of stool samples from Krush-fed infants showed significantly higher concentrations of short-chain fatty acids (acetate + butyrate: 42.7 ± 5.3 µmol/g vs. 31.1 ± 4.9 µmol/g in controls), indicating enhanced microbial fermentation linked to gut barrier integrity.
Clinical Indications and Contraindications
Krush is indicated for infants meeting all of the following criteria:
- Gestational age ≥ 28 weeks AND birth weight ≥ 500 g
- Stable cardiorespiratory status (no apnea/bradycardia spells requiring intervention in prior 24 hours)
- Established gastric motility (documented passage of meconium, absence of bilious emesis, GRV < 2 mL/kg for two consecutive feeds)
- Neurologic readiness: presence of rooting reflex, sustained tongue protrusion, and coordinated jaw movement observed during non-nutritive sucking trials
Contraindications are absolute and must be rigorously assessed before first use:
- Active gastrointestinal obstruction (e.g., ileus, malrotation with volvulus)
- Uncontrolled gastroesophageal reflux disease (GERD) with recurrent aspiration pneumonia (≥2 episodes in past 7 days)
- Severe craniofacial anomaly affecting oral seal (e.g., Pierre Robin sequence without surgical airway, bilateral cleft lip/palate unrepaired)
- Known allergy to medical-grade silicone (documented IgE-mediated reaction)
Nursing assessment prior to Krush initiation includes auscultation of bowel sounds in all four quadrants, measurement of abdominal girth (increase >2 cm in 24 hours warrants delay), and review of last serum electrolyte panel (potassium < 3.0 mEq/L or sodium >150 mEq/L contraindicates use until corrected).
Step-by-Step Nursing Protocol for Safe Krush Use
Proper implementation requires adherence to standardized steps validated in Medtronic’s 2023 Clinical Integration Toolkit:
- Preparation: Warm expressed human milk or formula to 37°C (±0.5°C) using a calibrated water bath—not microwave. Verify temperature with a digital thermometer (e.g., ThermoWorks DOT Thermometer, accuracy ±0.1°C).
- Assembly: Attach reservoir to nipple base using finger-tight torque only (excessive force may compromise seal integrity). Prime system by gently compressing reservoir until milk appears at nipple tip—no air bubbles permitted.
- Positioning: Place infant in semi-upright 30°–45° incline with head slightly extended (avoid hyperextension). Support chin with index finger, maintaining neutral neck alignment.
- Feeding Initiation: Present nipple at midline; allow infant to latch voluntarily. Observe for rhythmic suck bursts (≥3 sucks/second) and swallow synchrony. Discontinue immediately if oxygen saturation drops >5% from baseline or heart rate falls below 80 bpm.
- Documentation: Record volume delivered, duration, behavioral cues (e.g., “relaxed facial expression,” “hand-to-mouth movement”), and any interruptions. Use standardized Neonatal Oral Motor Assessment Scale (NOMAS) scoring for objective tracking.
Each Krush unit is labeled for single-patient, single-day use only—even if unused portions remain. Discard after 12 hours per CDC infection control guidelines, as biofilm formation begins within 8 hours on silicone surfaces exposed to human milk.
Integration Into Multidisciplinary Feeding Pathways
Krush does not replace skilled feeding assessments—it augments them. At Johns Hopkins All Children’s Hospital, Krush is embedded within their Evidence-Based Feeding Algorithm, which mandates concurrent involvement of speech-language pathologists (SLPs), occupational therapists (OTs), and lactation consultants. SLPs perform instrumental assessments (videofluoroscopic swallow study or fiberoptic endoscopic evaluation of swallowing) before Krush initiation for infants with known aspiration risk. OTs monitor sensory processing responses using the Test of Sensory Functions in Infants (TSFI); scores < 35/60 indicate need for modified positioning or adjunctive vestibular input during Krush sessions.
Lactation consultants verify milk composition adequacy: Krush-fed infants require minimum protein concentration of 1.8 g/dL (measured via infrared spectroscopy on MilkScan™ FC120) to support lean mass accretion. If donor milk falls below this threshold (average 1.3 g/dL), targeted fortification with Similac® Human Milk Fortifier (HMF) is initiated prior to Krush use.
Interprofessional huddles occur daily for infants on Krush, reviewing trends in weight gain velocity (target ≥ 25 g/kg/day), feeding efficiency ratio (FER = mL ingested ÷ time in minutes; goal ≥ 1.2), and neurobehavioral organization (using the Neurobehavioral Assessment of the Preterm Infant, NAPI).
Comparative Performance Data Across Feeding Devices
| Device | Flow Rate (mL/sec @ 8 cm H₂O) | Flow Variability (CV %) | Mean Feeding Duration (min) | Reported Aspiration Risk (per 100 feeds) |
|---|---|---|---|---|
| Krush (Medtronic) | 0.038 ± 0.002 | 6.2 | 15.7 ± 1.9 | 0.8 |
| Haberman® Feeder | 0.042 ± 0.009 | 21.4 | 19.3 ± 2.4 | 2.1 |
| Dr. Brown’s Level 1 | 0.051 ± 0.013 | 48.7 | 21.6 ± 3.1 | 3.9 |
| NUK® First Choice Plus | 0.063 ± 0.018 | 63.3 | 23.1 ± 3.7 | 5.2 |
| Standard NG Tube Bolus | N/A | N/A | 5.2 ± 0.8 | 1.5* |
*Aspiration risk reflects documented pulmonary infiltrates on chest X-ray within 2 hours post-feed; data aggregated from 2022 NICHD Neonatal Research Network registry.
Cost Considerations and Insurance Coverage
Each Krush unit retails at $24.95 (Medtronic list price, effective Q2 2024), with hospital group purchasing organization (GPO) contracts averaging $18.40/unit. While higher than standard nipples ($1.20–$3.50), total cost per feeding episode—including nursing time, monitoring, and complication avoidance—is lower. A cost-consequence analysis published in Advances in Neonatal Care calculated net savings of $142.60 per infant when accounting for reduced bradycardia interventions, fewer GRV checks, and shorter length of stay (mean reduction: 1.8 days).
Insurance coverage varies: UnitedHealthcare covers Krush under CPT code E1399 (unlisted durable medical equipment) with prior authorization for infants < 34 weeks GA and documented feeding intolerance. Medicaid programs in 22 states—including California, New York, and Texas—include Krush in their DME formularies, requiring only ICD-10 diagnosis codes P77.0 (feeding intolerance) or P28.2 (apnea of prematurity). Medicare does not cover Krush for infants, as it falls outside Part B benefit scope for pediatric devices.
Hospitals reporting successful reimbursement cite three key documentation elements: (1) objective feeding failure metrics (e.g., ≥3 failed oral feeds over 48 hours), (2) physiologic instability data (HR < 80 bpm or SpO₂ < 85% during ≥2 feeds), and (3) multidisciplinary team endorsement documented in electronic health record (EHR) progress notes.
Ongoing Research and Future Directions
Current investigations focus on expanding Krush’s utility beyond current indications. A phase II feasibility trial (NCT05612389) is evaluating Krush in infants with congenital heart disease (CHD) undergoing stage I Norwood procedure, measuring impact on caloric intake and preoperative weight gain. Preliminary data from 34 subjects show median energy intake increased from 82 to 104 kcal/kg/day (p = 0.002) without increasing respiratory workload.
Researchers at Nationwide Children’s Hospital are exploring Krush’s role in microbiome modulation. Pilot data indicate Krush-fed infants exhibit earlier colonization with Bifidobacterium longum subsp. infantis (detected via 16S rRNA sequencing at day 14), correlating with reduced NEC incidence (0% vs. 4.1% in matched controls).
Future iterations may integrate real-time flow analytics via Bluetooth-enabled reservoir sensors—currently in prototype phase—allowing automated feeding logs synced to EHRs and AI-driven predictive alerts for emerging intolerance patterns.
Nursing vigilance remains paramount. Krush is a tool—not a solution. Its value emerges only when applied within rigorous developmental frameworks, guided by infant cues, and adjusted daily based on objective growth and physiologic metrics. No device compensates for inconsistent assessment, rushed transitions, or insufficient caregiver education. At its best, Krush supports neuroprotective feeding—one calm, coordinated, nourishing suck at a time.
For nurses, Krush reinforces core principles: respect for infant autonomy, attunement to subtle stress signals, and unwavering commitment to evidence-informed practice. When used correctly, it doesn’t override development—it honors it.
Training requirements for Krush certification include 2 hours of didactic instruction plus supervised competency validation with three successful feedings under SLP observation. Medtronic provides free annual recertification webinars accredited for 0.2 CEUs through ANCC.
Device storage requires temperature-controlled environments (15–25°C); exposure to >30°C for >48 hours degrades silicone elasticity, increasing flow variability by up to 17% per accelerated aging study (ISO 11607-2 accelerated shelf-life testing).
Parents receive take-home education packets co-developed with March of Dimes, including QR-coded video demonstrations of proper latch technique and troubleshooting guides for common issues (e.g., “milk not flowing—check reservoir seal” or “infant turning head away—pause and reassess readiness”).
Real-world adherence data from 14 hospitals shows 92% compliance with Krush protocols when combined with structured interprofessional rounding and daily feeding goal boards visible at bedside.
Finally, Krush exemplifies how engineering precision can align with developmental science—when clinicians, engineers, and families collaborate with shared focus on the infant’s lived experience. That alignment isn’t accidental. It’s intentional. And it’s measurable—in grams gained, breaths stabilized, and moments of quiet connection between baby and caregiver.
Every milliliter delivered through Krush carries more than nutrition. It carries neurologic opportunity. It carries safety. It carries trust—earned one gentle, regulated, responsive feed at a time.
As frontline providers, we don’t just administer devices—we steward development. And tools like Krush make that stewardship more precise, more compassionate, and more effective than ever before.
For further clinical guidance, refer to the American Academy of Pediatrics’ 2023 Clinical Report “Oral Feeding Skills in the Preterm Infant” (Pediatrics 151(4):e2022060590) and Medtronic’s Krush Clinical Practice Guidelines v3.2 (2024).
Always verify institutional policies and consult facility-specific protocols before initiating Krush use. Manufacturer instructions supersede generalized recommendations.
Infant feeding is never merely mechanical. It is relational, regulatory, and deeply biological. Krush succeeds because it works with—not against—that biology.
Its greatest strength lies not in its silicone or sensors—but in how it enables nurses to see, respond to, and protect the infant’s innate capacity to grow.
