Cardiorespiratory events with bolus versus continuous enteral feeding in healthy preterm infants

Effect of different tube feeding methods on gastroesophageal reflux features in preterm infants: a pH-impedance monitoring study

A stepwise approach is currently considered the best choice to manage gastroesophageal reflux (GER) in preterm infants. This study aimed to evaluate the effect of different tube feeding techniques on GER frequency and features in symptomatic tube-fed preterm neonates. Tube-fed infants < 34 weeks' gestation were eligible for this prospective, bicentric, cross-over study if, due to GER symptoms, they underwent a diagnostic 24-h combined pH and multiple intraluminal impedance (pH-MII) monitoring. During the monitoring period, each infant received the same feeding cycle, repeated twice: continuous tube feeding, bolus feeding followed by tube feeding permanence and by tube feeding removal. The impact of these three feeding modalities on pH-MII GER features was assessed. Thirty-one infants were enrolled. Despite a low number of reflux episodes, a significant decrease in total GERs (P < 0.001), in GERs detected by pH monitoring (P < 0.001), and in both acid and non-acid GERs detected by MII (P < 0.001 and P = 0.009, respectively) was observed in association with continuous feeding compared to bolus feeds, followed or not by tube feeding removal. Compared to continuous feeding, both bolus feeding modalities were associated with a significantly higher number of proximal GERs (P < 0.001). No difference in any pH-MII parameter was observed in relation to tube feeding persistence after bolus feeding administration.

CONCLUSIONS

Continuous feeding and boluses may have a different impact on pH-MII GER features in symptomatic tube-fed preterm infants, whereas the permanence of the feeding tube across LES did not seem to worsen GER indexes.

WHAT IS KNOWN

• Due to the functional and anatomical immaturity of the gastrointestinal tract, gastroesophageal reflux (GER) is common in preterm infants. • A stepwise therapeutical approach which firstly undertakes conservative strategies is the most advisable choice to avoid potentially harmful pharmacological overtreatments in the preterm population.

WHAT IS NEW

• Continuous feeding and boluses may have a different impact on GER features assessed by pH-MII monitoring in tube-fed preterm infants. • The permanence of the feeding tube during or after the feeding period did not seem to worsen GER occurrence. • By reducing GER features, especially acid GER, continuous feeding may potentially contribute to limit the need for antiacid medications in this population.

Oxygenation Instability during Bolus versus Continuous Feeding among Very Low Birth Weight Premature Infants, Supported by Noninvasive Ventilation: A Randomized Prospective Study

OBJECTIVE

This study aimed to compare oxygenation instability, as documented by the oxygen saturation (SpO2) histograms, during bolus (over 30 minutes) versus continuous (over 2 hours) feeding among very low birth weight (VLBW) premature infants, supported with noninvasive ventilation (NIV).

STUDY DESIGN

This was a randomized prospective study. VLBW infants supported with NIV received three consecutive feeds in a random order of bolus-continuous-bolus or continuous-bolus-continuous. During each feed, 30 minutes and 2 hours histograms were documented.

RESULTS

Twenty-four infants (birth weight [mean ± standard deviation, SD] 820 ± 168 g, gestational age [mean ± SD] 27.0 ± 1.6 weeks) were included in our study (12 infants started with bolus feeding and 12 with continuous feeding) and 72 histograms were obtained (36 during bolus feeding and 36 during continuous feeding). No differences in mean fraction of inspired oxygen (FiO2), and number of apnea events were observed between the two feeding modes. Oxygenation instability as assessed by time spent in different SpO2 ranges and histogram types (stable or unstable) was comparable during bolus and continuous feedings. Changing feeding mode from bolus to continuous or vice versa did not significantly change the oxygenation instability of the group, though individual infants did show a consistence response to feeding length changes.

CONCLUSION

Among VLBW infants supported with NIV, oxygenation instability, as documented by SpO2 histograms, was comparable between bolus and continuous feedings. Individual infants may benefit from specific feeding length, and this can be easily demonstrated by the SpO2 histograms.

KEY POINTS

· Feeding length did not affect oxygenation instability of preterm infants on noninvasive respiratory Support.. · Oxygen saturation histograms allow objective quantification of oxygenation instability at the bedside.. · Individual infants benefit from specific feeding length, as demonstrated by SpO2 histograms..

Enteral Nutrition in Preterm Infants (2022): A Position Paper From the ESPGHAN Committee on Nutrition and Invited Experts

OBJECTIVES

To review the current literature and develop consensus conclusions and recommendations on nutrient intakes and nutritional practice in preterm infants with birthweight <1800 g.

METHODS

The European Society of Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Committee of Nutrition (CoN) led a process that included CoN members and invited experts. Invited experts with specific expertise were chosen to represent as broad a geographical spread as possible. A list of topics was developed, and individual leads were assigned to topics along with other members, who reviewed the current literature. A single face-to-face meeting was held in February 2020. Provisional conclusions and recommendations were developed between 2020 and 2021, and these were voted on electronically by all members of the working group between 2021 and 2022. Where >90% consensus was not achieved, online discussion meetings were held, along with further voting until agreement was reached.

RESULTS

In general, there is a lack of strong evidence for most nutrients and topics. The summary paper is supported by additional supplementary digital content that provide a fuller explanation of the literature and relevant physiology: introduction and overview; human milk reference data; intakes of water, protein, energy, lipid, carbohydrate, electrolytes, minerals, trace elements, water soluble vitamins, and fat soluble vitamins; feeding mode including mineral enteral feeding, feed advancement, management of gastric residuals, gastric tube placement and bolus or continuous feeding; growth; breastmilk buccal colostrum, donor human milk, and risks of cytomegalovirus infection; hydrolyzed protein and osmolality; supplemental bionutrients; and use of breastmilk fortifier.

CONCLUSIONS

We provide updated ESPGHAN CoN consensus-based conclusions and recommendations on nutrient intakes and nutritional management for preterm infants.

'Propped and prone' positioning reduces respiratory events in spontaneously breathing preterm infants: A randomised triple crossover study

AIM

We compared effects of infant positioning and feed-rate interventions on respiratory events and oximetry parameters in spontaneously breathing preterm infants born <32 weeks gestation managed in a neonatal unit.

METHODS

A randomised triple crossover design was employed. n = 68 infants underwent three test conditions A: control (supine/flat, gravity bolus feeds), B: position intervention (propped/prone) and C: feed-rate intervention (continuous pump feeds) in randomised sequence over three consecutive days. Primary outcomes were number of events (apnoea, bradycardia and desaturation) and percentage time SpO₂  < 80% over 24 h. The secondary outcome was percentage time SpO₂  ≥ 88%. Treatment effects were estimated using linear mixed-effects models.

RESULTS

Propped/prone positioning significantly reduced events and improved percentage time SpO₂  < 80% and ≥88% compared to both other conditions (all P < 0.001). Outcomes for the feed-rate intervention were not significantly different to control.

CONCLUSIONS

Alternative infant positioning should be considered in preterm infants managed in the neonatal unit.

Continuous nasogastric milk feeding versus intermittent bolus milk feeding for preterm infants less than 1500 grams

BACKGROUND

Milk feedings can be given via nasogastric tube either intermittently, typically over 10 to 20 minutes every two or three hours, or continuously, using an infusion pump. Although the theoretical benefits and risks of each method have been proposed, their effects on clinically important outcomes remain uncertain.  OBJECTIVES: To examine the evidence regarding the effectiveness of continuous versus intermittent bolus tube feeding of milk in preterm infants less than 1500 grams.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to run comprehensive searches in the Cochrane Central Register of Controlled Trials (CENTRAL 2020, Issue 7) in the Cochrane Library; Ovid MEDLINE and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions; and CINAHL (Cumulative Index to Nursing and Allied Health Literature) on 17 July 2020. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs and quasi-RCTs comparing continuous versus intermittent bolus nasogastric milk feeding in preterm infants less than 1500 grams.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed all trials for relevance and risk of bias. We used the standard methods of Cochrane Neonatal to extract data. We used the GRADE approach to assess the certainty of evidence. Primary outcomes were: age at full enteral feedings; feeding intolerance; days to regain birth weight; rate of gain in weight, length and head circumference; and risk of necrotising enterocolitis (NEC).

MAIN RESULTS

We included nine randomised trials (919 infants) in this updated Cochrane Review. One study is awaiting classification. Seven of the nine included trials reported data from infants with a maximum weight of between 1000 grams and 1400 grams. Two of the nine trials included infants weighing up to 1500 grams. Type(s) of milk feeds varied, including human milk (either mother's own milk or pasteurised donor human milk), preterm formula, or mixed feeding regimens. In some instances, preterm formula was initially diluted. Earlier studies also used water to initiate feedings. We judged six trials as unclear or high risk of bias for random sequence generation. We judged four trials as unclear for allocation concealment. We judged all trials as high risk of bias for blinding of care givers, and seven as unclear or high risk of bias for blinding of outcome assessors. We downgraded the certainty of evidence for imprecision, due to low numbers of participants in the trials, and/or wide 95% confidence intervals, and/or for risk of bias. Continuous compared to intermittent bolus (nasogastric and orogastric tube) milk feeding Babies receiving continuous feeding may reach full enteral feeding almost one day later than babies receiving intermittent feeding (mean difference (MD) 0.84 days, 95% confidence interval (CI) -0.13 to 1.81; 7 studies, 628 infants; low-certainty evidence).  It is uncertain if there is any difference between continuous feeding and intermittent feeding in terms of number of days of feeding interruptions (MD -3.00 days, 95% CI -9.50 to 3.50; 1 study, 171 infants; very low-certainty evidence). It is uncertain if continuous feeding has any effect on days to regain birth weight (MD -0.38 days, 95% CI -1.16 to 0.41; 6 studies, 610 infants; low-certainty evidence). The certainty of evidence is low and the 95% confidence interval is consistent with possible benefit and possible harm. It is uncertain if continuous feeding has any effect on rate of gain in weight compared with intermittent feeding (standardised mean difference (SMD) 0.09, 95% CI -0.27 to 0.46; 5 studies, 433 infants; very low-certainty evidence). Continuous feeding may result in little to no difference in rate of gain in length compared with intermittent feeding (MD 0.02 cm/week, 95% CI -0.04 to 0.08; 5 studies, 433 infants; low-certainty evidence). Continuous feeding may result in little to no difference in rate of gain in head circumference compared with intermittent feeding (MD 0.01 cm/week, 95% CI -0.03 to 0.05; 5 studies, 433 infants; low-certainty evidence). It is uncertain if continuous feeding has any effect on the risk of NEC compared with intermittent feeding (RR 1.19, 95% CI 0.67 to 2.11; 4 studies, 372 infants; low-certainty evidence). The certainty of evidence is low and the 95% confidence interval is consistent with possible benefit and possible harm.

AUTHORS' CONCLUSIONS

Although babies receiving continuous feeding may reach full enteral feeding slightly later than babies receiving intermittent feeding, the evidence is of low certainty. However, the clinical risks and benefits of continuous and intermittent nasogastric tube milk feeding cannot be reliably discerned from current available randomised trials. Further research is needed to determine if either feeding method is more appropriate for the initiation of feeds. A rigorous methodology should be adopted, defining feeding protocols and feeding intolerance consistently for all infants. Infants should be stratified according to birth weight and gestation, and possibly according to illness.

Cardiovascular and cerebrovascular responses to cardio-respiratory events in preterm infants during the transitional period

KEY POINTS

Non-invasive simultaneous multiparametric monitoring allows the in vivo evaluation of cerebral and cardiovascular haemodynamic responses to different types of recurrent episodes of intermittent hypoxia and/or bradycardia, also defined as cardio-respiratory events (CRE), in preterm neonates during postnatal transition. By decreasing left cardiac output, bradycardia further contributes to cerebral hypoxia during CRE. The presence of a haemodynamically significant patent ductus arteriosus results in a deeper impairment of cerebral oxygen status in response to CRE, whereas the brain-sparing remodelling of the fetal circulation resulting from placental insufficiency is associated with more favourable haemodynamic responses to intermittent hypoxia. During transition, the haemodynamic impact of CRE is influenced not only by the event type, but also by specific clinical features; this highlights the importance of developing individualized approaches to reduce the hypoxic burden in this delicate phase.

ABSTRACT

The present observational prospective study aimed to investigate cerebral and cardiovascular haemodynamic responses to different types of cardio-respiratory events (CRE) in preterm infants during postnatal transition, as well as evaluate the impact of relevant clinical characteristics. Infants with gestational age (GA) <32 weeks and/or birth weight <1500 g were enrolled after birth. Cerebral oxygenation index (cTOI), fractional oxygen extraction (cFTOE), cardiac output (CO), cardiac contractility (iCON) and systemic vascular resistances (sVR) were simultaneously monitored over the first 72 h by near-infrared spectroscopy and electrical velocimetry. CRE were clustered into isolated bradycardia (IB), isolated desaturation (ID) and combined desaturation/bradycardia (DB). For each parameter, percentage changes from baseline (%Δ) were calculated. The impact of different CRE types and clinical variables on %Δ was evaluated with generalized estimating equations. In total, 1426 events were analysed. %ΔcTOI significantly differed among ID, IB and DB (P < 0.001), with the latter showing the greatest drop. %ΔcFTOE decreased significantly during DB (P < 0.001) and ID (P < 0.001) compared to IB. DB and IB were associated with more negative %ΔCO (P < 0.001) and more positive %ΔsVR (P < 0.001) compared to ID. A slight iCON reduction was observed during DB compared to ID (P = 0.043). Antenatal umbilical Doppler impairment, GA and the presence of a haemodynamically significant patent ductus arteriosus had a significant independent impact on %ΔcTOI, %ΔcFTOE and %ΔCO. During the transitional period, the haemodynamic responses to CRE are influenced by the event type and by specific neonatal characteristics, suggesting the importance of targeted individualized approaches for minimizing the risk of cerebral injury in the preterm population.

Apnea in preterm neonates: what's the role of gastroesophageal reflux? A systematic review

A causal relationship between gastro-esophageal reflux (GER) and apnea in preterm infants has been frequently hypothesized and is currently debated. The present study aims at reviewing the currently available scientific evidence, in order to clarify the role of GER on the occurrence of apnea and to help improving the clinical management of apneic preterm neonates. We performed a systematic literature search to identify all the clinical studies on preterm neonates that properly assessed the relationship between apnea and GER. Two-hundred and fifty-two papers, including 32 reviews and meta-analysis, were screened. Out of them, only 7 were included in the final analysis according to the selected criteria. Among them, 3 studies reported an increased frequency of apnea after reflux compared to reflux-free period and 4 denied a significant temporal relation. In conclusion, a minority of apneic events occurs soon after GER episodes. Whether this happens by chance or because of a causal relationship is still impossible to define. Based on the available data, empirical treatment with acid inhibitors is not recommended in neonates with apnea unless a proven temporal relation is shown by simultaneous esophageal pH-impedance and polysomnography or cardiorespiratory monitoring and in the absence of a clear clinical benefit.

Cardiorespiratory Events in Infants Born Preterm during the Transitional Period

OBJECTIVE

To investigate the features of cardiorespiratory events in infants born preterm during the transitional period, and to evaluate whether different neonatal characteristics may correlate with event type, duration, and severity.

STUDY DESIGN

Infants with gestational age (GA) <32 weeks and/or birth weight <1500 g were enrolled in this observational prospective study. Heart rate (HR) and peripheral oxygen saturation (SpO₂) were recorded continuously over the first 72 hours. Cardiorespiratory events of ≥10 seconds were clustered into isolated desaturation (SpO₂ <85%), isolated bradycardia (HR <100 bpm or <70% of baseline), or combined desaturation/bradycardia and classified as mild, moderate, or severe. The daily incidences of isolated desaturation, isolated bradycardia, and combined desaturation and bradycardia were analyzed. The effects of relevant clinical variables on cardiorespiratory event type and severity were assessed using generalized estimating equations.

RESULTS

Among the 1050 events analyzed, isolated desaturations were the most frequent (n = 625) and isolated bradycardias the least common (n = 171). The number of cardiorespiratory events increased significantly from day 1 to day 2 (P = .028). One in 5 events had severe characteristics; event severity was highest for combined desaturation and bradycardia (P < .001). Compared with other event types, the incidence of combined desaturation and bradycardia was inversely correlated with GA (P = .029) and was higher with the use of continuous positive airway pressure (P = .002). The presence of a hemodynamically significant patent ductus arteriosus was associated with the occurrence of isolated desaturations (P = .001) and with a longer duration of cardiorespiratory events (P = .003).

CONCLUSIONS

Cardiorespiratory events during transition exhibit distinct types, duration, and severity. Neonatal characteristics are associated with the clinical features of these events, indicating that a tailored clinical approach may reduce the hypoxic burden in preterm infants aged 0-72 hours.

Pre-discharge Cardiorespiratory Monitoring in Preterm Infants. the CORE Study

Objective: Ensuring cardiorespiratory (CR) stability is essential for a safe discharge. The aim of this study was to assess the impact of a new pre-discharge protocol named CORE on the risk of hospital readmission (RHR). Methods: Preterm infants admitted in our NICU between 2015 and 2018 were randomly assigned to CORE (exposed) or to standard (not-exposed) discharge protocol. CORE included 24 h-clinical observation, followed by 24 h-instrumental CR monitoring only for high-risk infants. RHR 12 months after discharge and length of stay represent the primary and secondary outcomes, respectively. Results: Three hundred and twenty three preterm infants were enrolled. Exposed infants had a lower RHR (log-rank p < 0.05). The difference was especially marked 3 months after discharge (9.09 vs. 21.6%; p = 0.004). The hospital length of stay in exposed and not-exposed infants was 39(26-58) and 43(26-68) days, respectively (p = 0.16). Conclusions: The CORE protocol could help neonatologists to define the best timing for discharge reducing RHR without lengthening hospital stay.

Continuous Feedings Are Not Associated With Lower Rates of Gastroesophageal Reflux When Compared With Bolus Feedings

Gastroesophageal reflux disease is common in children with gastrostomy tubes. Clinicians often transition to continuous feedings in an attempt to reduce reflux burden, though there is limited data to support this practice. In this retrospective study, we analyzed 24-hour multichannel intraluminal impedance with pH studies in 18 children with gastrostomy tubes receiving exclusive enteral nutrition with a combination of daytime bolus and overnight continuous feedings. There were no significant differences in the rate of reflux (reflux events per hour) between no feeding, bolus feeding, and continuous feeding periods overall or stratified by prior fundoplications (P > 0.40). After adjusting for age, BMI, feeding rate, and feeding volume in multivariate analysis, there were no significant differences in the risk of reflux between different feeding periods. These results suggest that continuous feedings may not offer a significant advantage in reducing reflux burden.

Continuous feeding versus intermittent bolus feeding for premature infants with low birth weight: a meta-analysis of randomized controlled trials

Background/objectives

Clinical risks and advantages of both continuous feeding and intermittent feeding for preterm infants have been presented in previous studies. To determine the most appropriate feeding method for low-birth-weight infants, a meta-analysis was conducted.

Subjects/methods

Articles related to this topic were searched in PubMed, EMBASE, and Cochrane Library electronic database from the onset to May 2019. Heterogeneity analysis was performed with Chi-square and I² test. Pooled analysis was based on fixed effects model, if heterogeneity between the eligible studies was negligible (I² < 50%, P > 0.05). In contrast, a random effects model was carried out. The quality of including studies were evaluated by Cochrane assessment tool.

Results

A total of 1030 articles identified. Altogether, eight articles including 707 infants were included in final analysis based on eligibility criteria. In continuous feeding infants, time to achieving full feeds was longer (weight mean difference 0.98 (95% CI 0.26–1.71, P = 0.008) days) compared with intermittent feeding infants. Pooled analysis indicated there were no significant difference in other variables such as feeding intolerance, duration of hospitalization, days to regain birth weight, days to first successful oral feeding, duration of parenteral feeding, weight growth, length increment, head circumference growth, proven necrotizing enterocolitis, and probable necrotizing enterocolitis. In subgroup analysis for birth weight (<1000 g and >1000 g), we did not identify significant difference in time to full feeds, time to regain birth weight, and duration of hospitalization.

Conclusions

Intermittent feeding may be more beneficial for low-birth weight infants, However, well-designed studies and evidenced-based clinical practice are required to determine the most appropriate feeding method for premature infants with low birth weight.

Temporal Progression of Fatty Acids in Preterm and Term Human Milk of Mothers from Switzerland

We longitudinally compared fatty acids (FA) from human milk (HM) of mothers delivering term and preterm infants. HM was collected for 4 months postpartum at 12 time points for preterm and for 2 months postpartum at 8 time points for term group. Samples were collected from the first feed of the morning, and single breast was fully expressed. FA were analyzed by gas chromatography coupled with flame ionization detector. Oleic, palmitic and linoleic acids were the most abundant FA across lactation and in both groups. Preterm colostrum contained significantly (p < 0.05) higher 8:0, 10:0, 12:0, sum medium chain fatty acids (MCFA), 18:3 n-3 FA compared to term counterparts. Preterm mature milk contained significantly higher 12:0, 14:0, 18:2 n-6, sum saturated fatty acids (SFA), and sum MCFA. We did not observe any significant differences between the preterm and term groups for docosahexaenoic acid, arachidonic acid and eicosapentaenoic acid at any stage of lactation. Overall, preterm milk was higher for SFA with a major contribution from MCFA and higher in 18:2 n-6. These observational differences needs to be studied further for their implications on preterm developmental outcomes and on fortification strategies of either mothers’ own milk or donor human milk.

A Strategy to Reduce Critical Cardiorespiratory Alarms due to Intermittent Enteral Feeding of Preterm Neonates in Intensive Care

Background

Many preterm infants require enteral feeding as they cannot coordinate sucking, swallowing, and breathing. In enteral feeding, milk feeds are delivered through a small feeding tube passed via the nose or mouth into the stomach. Intermittent milk feeds may either be administered using a syringe to gently push milk into the infant’s stomach (push feed) or milk can be poured into a syringe attached to the tube and allowed to drip in by gravity (gravity feed). This practice of enteral feeding is common in neonatal intensive care units. There is, however, no evidence in the literature to recommend the use of one method of feeding over the other.

Objective

The aim of this study was to investigate which of the two methods of feeding is physiologically better tolerated by infants, as measured by the incidence of critical cardiorespiratory alarms during and immediately after feeding.

Methods

We conducted a prospectively designed observational study with records of all feeding episodes in infants of gestational age less than 30 weeks at birth and with a minimum enteral intake of 100 mL/kg/day. In total, 2140 enteral feeding episodes were noted from 25 infants over 308 infant-days with records for several characteristics of the infants (eg, gestational age), feeding (eg, the position of infants), and of nursing-care events before feeding (eg, diapering). Logistic regression with mixed effects was used to model cardiorespiratory alarms for the push and gravity methods of feeding.

Results

After adjustments were made for all confounding variables, the position of infants was found to be statistically significant in changing the outcome of critical alarms for the two methods of feeding (P=.02). For infants in the lateral position, push feeds led to 40% more instances of one or more critical cardiorespiratory alarms in comparison with the gravity method. Both methods of feeding created a statistically comparable number of alarms for infants in the prone position.

Conclusions

This study provides objective data that may assist in optimizing enteral feeding protocols for premature infants. The incidence of critical cardiorespiratory alarms for infants in the lateral position can be lowered by the use of gravity instead of push feeding. No differences were observed between the two types of feeding when infants were in the prone position.

Feeding Problems and Their Underlying Mechanisms in the Esophageal Atresia-Tracheoesophageal Fistula Patient

Feeding difficulties such as dysphagia, coughing, choking, or vomiting during meals, slow eating, oral aversion, food refusal, and stressful mealtimes are common in children with repaired esophageal atresia (EA) and the reasons for this are often multifactorial. The aim of this review is to describe the possible underlying mechanisms contributing to feeding difficulties in patients with EA and approaches to management. Underlying mechanisms for these feeding difficulties include esophageal dysphagia, oropharyngeal dysphagia and aspiration, and aversions related to prolonged gastrostomy tube feeding. The initial diagnostic evaluation for feeding difficulties in a patient with EA may involve an esophagram, videofluoroscopic imaging or fiberoptic endoscopic evaluation during swallowing, upper endoscopy with biopsies, pH-impedance testing, and/or esophageal motility studies. The main goal of management is to reduce the factors contributing to feeding difficulties and may include reducing esophageal stasis, maximizing reflux therapies, treating underlying lung disease, dilating strictures, and altering feeding methods, routes, or schedules.