Lesson
The Enteral Decision
Use the gastrointestinal tract when it can safely receive and absorb nutrients, but separate a functioning gut from a patient who is not yet adequately resuscitated.
- Indications and goals
- Hemodynamic stability
- Contraindications
- Early critical care feeding
Oral intake cannot safely meet the target
Digestion and absorption are usable
Resuscitation is complete and stable
Choose oral, gastric, or postpyloric delivery
Prefer the gut when it is usable
Enteral nutrition delivers nutrients through the gastrointestinal tract by mouth or feeding tube. It supports gut structure and function, avoids central venous access, and is generally preferred to parenteral nutrition when digestion and absorption are adequate. It does not replace an oral diet when safe oral intake can meet the patient's needs.
Connect the route to its advantages
Enteral nutrition generally costs less than parenteral nutrition and uses the gastrointestinal tract, helping prevent intestinal atrophy. Infection, hyperglycemia, cholelithiasis, and cholestasis are concerns with parenteral nutrition, but comparative benefits depend on the patient and treatment setting. The 2022 ASPEN guideline found no significant clinical-outcome difference between early exclusive enteral and parenteral nutrition with similar energy delivery in critically ill adults who were candidates for enteral feeding; either route was acceptable during the first ICU week. The supporting interventions lasted only 5 to 7 days, so this finding does not establish equal outcomes for prolonged treatment or patients unable to tolerate enteral nutrition. Consider gastrointestinal suitability, tolerance, cost, and practical delivery rather than promising fewer infections solely from the route. Enteral feeding still requires aspiration precautions and nutrition and hydration monitoring.
Recognize the patient who needs support
Assess nutrition support when safe oral intake cannot meet the patient’s needs. Relevant settings include dysphagia associated with neurologic disease or cancer treatment, critical illness, and requirements that cannot be met orally. These settings prompt assessment rather than establish an indication by diagnosis alone. Confirm that the proposed route can safely deliver nutrients to a functioning gastrointestinal tract. Selected patients with gastric outlet obstruction may be candidates for feeding beyond the obstruction when the small bowel is usable; complete intestinal obstruction requires withholding enteral feeding and clinical assessment. Match initiation to nutrition risk, anticipated intake, perfusion, and tolerance. Expected duration also guides access selection. A diagnosis or fixed day count alone does not establish a feeding indication.
Do not feed through active instability
Suspected bowel ischemia or complete intestinal obstruction requires withholding enteral feeding and urgent clinical assessment. The 2016 SCCM/ASPEN guideline advises withholding feeding during hemodynamic instability until resuscitation and stability are achieved. If vasopressor requirements escalate or new abdominal findings suggest ischemia, hold feeding and reassess; merely stopping advancement can leave an unsafe infusion running. Stable low-dose vasopressor support does not automatically exclude carefully monitored feeding. Assess the whole clinical pattern: the 2023 ASPEN practice tool states that lactate alone is not an established measure of enteral tolerance.
Use early feeding with clinical judgment
The 2016 SCCM/ASPEN guideline recommends considering enteral nutrition within 24 to 48 hours for critically ill adults unable to maintain oral intake, after adequate resuscitation and stabilization. Apply nutrition risk as well as timing: patients with low nutrition risk, normal baseline nutrition status, and low disease severity may not require specialized nutrition therapy during the first ICU week. Reassess risk daily. Early initiation does not mandate immediate full-rate feeding; choose dose and advancement according to the patient's perfusion, tolerance, and refeeding risk.
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Lesson
Access and Route Selection
Access is chosen by expected duration, anatomy, gastric emptying, aspiration risk, procedural burden, and the therapies that must pass through the tube.
- Gastric versus postpyloric
- Nasal versus percutaneous
- Placement confirmation
- ENFit safety
Gastric or postpyloric
Bolus, intermittent, continuous when tolerated
Controlled small bowel delivery
Gastrostomy or jejunostomy
Name where the tube ends
A nasogastric tube passes through the nose into the stomach. A gastrostomy reaches the stomach through the skin; PEG denotes a percutaneous endoscopic gastrostomy. A jejunostomy reaches the jejunum, part of the small intestine; PEJ denotes a percutaneous endoscopic jejunostomy. Gastric and jejunal access are different destinations, so identify the actual tube tip rather than treating every feeding tube as a nasogastric tube.
Separate duration from destination
Nasogastric tubes are primarily used for short-term support. A longer anticipated course calls for reassessment of access, but duration and tube destination are separate questions: a gastrostomy reaches the stomach, while a jejunostomy reaches the small intestine. Longer support does not by itself mean that the tube must end in the jejunum. Check whether the stomach is usable, identify the actual tube tip, and assess the patient before choosing the access procedure. Tube feeding can supplement other intake or provide complete nutrition support.
Start with the stomach when appropriate
Use gastric access when the stomach functions adequately and there is no severe emptying disorder or gastric outlet obstruction. Gastric feeding offers bolus, intermittent, and continuous schedule options; choose among them according to tolerance and aspiration risk. Nasal access is usually for shorter support, while longer support warrants individualized assessment for percutaneous access. Duration does not determine the tip destination by itself. Review anatomy and contraindications before placement; head or facial injury can make a nasal route unsuitable.
Move beyond the pylorus for a reason
Postpyloric delivery places the tip in the duodenum or jejunum. Consider it when severe gastroparesis, gastric outlet obstruction, or persistent gastric intolerance prevents an adequate gastric plan, or when aspiration risk warrants small bowel access. This choice does not eliminate aspiration: oral secretions and reflux can still be aspirated. Use a controlled schedule matched to tolerance. The 2024 AuSPEN pediatric consensus recommends continuous pump delivery for children receiving jejunal feeds because jejunal reservoir capacity is limited. Adult schedules remain individualized; the 2017 ASPEN safe-practice guidance describes periodic continuous jejunal feeding, including nocturnal schedules, rather than requiring every patient to remain connected for 24 hours.
Confirm before first use
The 2017 ASPEN safe-practice recommendations call for a properly obtained and interpreted radiograph showing the entire tube course and tip before an adult's blindly placed short-term feeding tube is first used for feeds, fluids, or medications. Air auscultation alone is unreliable, and absence of respiratory symptoms does not establish placement. Mark and document external length, check securement, and reassess possible migration; hold use until the intended position is confirmed when location is uncertain. A previous image establishes location only at that time. Pediatric and neonatal confirmation requires a population-specific protocol that weighs radiation exposure, availability, and misplacement risk. The same recommendations support two nonradiologic methods, such as length measurement and aspirate pH testing, when repeated imaging is not feasible, with radiography for inconclusive results. They identify radiography as best practice for high-risk children, including neonates and sedated or critically ill children. Neither population should rely on auscultation alone.
Prevent wrong-route connections
Enteral-specific connectors such as ENFit are designed to reduce wrong-route connections between enteral and nonenteral systems, including intravenous lines. Before each use, verify the connection and trace the line from the patient to its source; repeat this check when replacing equipment or transferring care. Label enteral equipment and use a compatible enteral syringe, but do not rely on color or labels alone. Never force a connection or modify a connector to defeat its safety features. Check device-specific compatibility before using an enteral transition adapter. A connector that fits does not confirm the tube tip or establish that a medication formulation is suitable for that tube.
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Lesson
Delivery and the Feeding Prescription
The prescription links a daily nutrient and fluid target to a formula, route, rate, schedule, flush plan, and advancement strategy.
- Bolus, intermittent, and continuous delivery
- Daily volume targets
- Rate calculations
- Advancement and interruptions
What must reach the patient
Volume divided by running hours
Continuous, cyclic, intermittent, bolus
Account for every interruption
Match method to access and tolerance
Bolus and intermittent schedules provide separate feedings rather than an uninterrupted infusion. Gastric bolus feeding can fit meals and home routines when tolerated and aspiration risk is low. Continuous infusion offers controlled delivery for patients at high aspiration risk or unable to tolerate gastric boluses; small bowel delivery also requires a tolerance-based schedule. A cyclic pump schedule runs during a defined part of the day, leaving time off feeding. That interval can support activity and home routines, but it does not guarantee appetite or adequate oral intake. Match the method, rate, and running hours to the tube tip, patient condition, prescribed daily volume, and tolerance.
Prescribe the full system
Name the product, access site, method, goal rate or volume, schedule, advancement, water flushes, and monitoring. A rate without a duration does not define daily delivery. For example, 60 mL per hour for 20 hours provides 1,200 mL, not the 1,440 mL that would be delivered over 24 hours.
State how a calculated rate is rounded
Divide the prescribed daily volume by the actual feeding hours to calculate mL per hour. A hypothetical 1,800 mL target over 22 hours requires 81.818... mL per hour, or 81.8 mL per hour to the nearest tenth. That rounded rate delivers 1,799.6 mL over 22 hours, so it approximates the target rather than equaling it exactly. Use the stated rounding instruction and check the resulting volume; a calculation alone does not establish a safe patient-specific pump setting.
Advance according to risk
Individualize advancement according to perfusion, gastrointestinal tolerance, access site, nutrition risk, and electrolyte status. A stable patient with an established tube may progress differently from a patient recovering from shock or starting postpyloric feeding. The 2020 ASPEN refeeding consensus recommends checking potassium, magnesium, and phosphate before nutrition begins and delaying initiation or increases in calories when these levels are severely low until corrected. Other low levels in a patient at refeeding risk warrant supplementation and consideration of delaying advancement. Monitor the clinical pattern, glucose, fluid balance, and electrolytes during cautious initiation; a precipitous fall or levels that are difficult to correct require prompt reassessment of energy delivery and electrolyte treatment. Include calories from intravenous dextrose when assessing refeeding exposure rather than advancing by the clock alone.
Manage interruptions deliberately
Procedures, medication windows, tube problems, and routine care can reduce the amount of nutrition received. Assess which holds are necessary, minimize avoidable interruptions, and document actual feeding time and volume. A volume-based protocol specifies a daily volume goal and permits adjustments within prescribed limits to account for missed delivery. Reassess the tube destination, patient condition, and tolerance before increasing the rate; the protocol is not permission for unrestricted catch-up feeding. Compare delivery records with the expected volume rather than relying on pump settings alone.
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Lesson
Formula Selection and Hydration
Match formula composition to nutrient, volume, digestion, absorption, electrolyte, and tolerance needs; greater complexity does not establish greater benefit.
- Polymeric and peptide-based formulas
- Caloric density
- Fiber and disease-specific products
- Free water and renal solute load
Use when digestion and absorption work
Consider for a defined absorption or tolerance problem
Check product water and daily volume
Formula plus flushes plus other intake
Read energy from the stated formula label
For the nutrition-label calculations used here, carbohydrate and protein provide 4 kcal per gram and fat provides 9 kcal per gram. A hypothetical serving labeled 240 kcal with 16 g protein, 23 g carbohydrate, and 9 g fat supplies 64 kcal from protein, 92 kcal from carbohydrate, and 81 kcal from fat using those factors. Protein contributes 64 divided by the stated 240 kcal times 100, or 26.7% to the nearest tenth. Use the label's declared total when a question asks for the percentage of labeled calories; the simple 4/4/9 sum, 237 kcal in this example, need not exactly match that declared total. Enteral carbohydrate energy must not be confused with the 3.4 kcal per gram used for parenteral dextrose.
Scale nutrients to the amount actually received
Apply the delivered fraction of the labeled serving to its energy and nutrient amounts. If the hypothetical 240 kcal serving above is 240 mL and only 180 mL is delivered, the patient receives 180 divided by 240, or three quarters of a serving: 180 kcal and 12 g protein. Half of the full labeled serving supplies 46 kcal from carbohydrate. Count the amount received after spills or incomplete delivery. These are stated-label exercises; verify the actual product and serving information before calculating a clinical prescription.
Use standard formulas when digestion works
Standard polymeric formulas provide intact protein and are appropriate for many patients with adequate digestion and absorption. The 2016 SCCM/ASPEN guideline recommends a standard polymeric formula when initiating enteral nutrition in critically ill adults. Peptide-based formulas contain hydrolyzed protein; amino-acid-based elemental formulas provide free amino acids. Fat composition and energy density vary by product. Consider a hydrolyzed formula for a defined absorption or tolerance problem rather than choosing greater hydrolysis merely because it sounds easier to absorb. Review the actual composition, patient response, evidence, and cost.
Use density to solve a volume problem
Higher energy density can deliver the same energy in less formula volume. For example, the 2016 SCCM/ASPEN guideline suggests considering energy-dense formulas for critically ill adults with acute respiratory failure who need volume restriction, especially with volume overload; this is an expert-consensus recommendation. Energy density alone does not establish free-water delivery, viscosity, or renal solute load. Use product data and the volume actually received to calculate formula water, then compare all fluid sources with the individualized target. Do not assume formula volume equals water or that a concentrated formula meets hydration needs.
Treat fiber and specialty claims carefully
Match fiber use to bowel function and patient stability. In critically ill adults, the 2016 SCCM/ASPEN guideline advises against routine mixed-fiber formulas solely to prevent diarrhea. Selected stable patients with persistent diarrhea may warrant a fiber strategy after reviewing medications and other causes. Avoid both soluble and insoluble fiber when a critically ill patient is at high risk of bowel ischemia or has severe dysmotility. Disease-specific formulas need a rationale based on composition, clinical evidence, tolerance, and cost; a diagnosis or higher price alone does not establish superiority. Selected indications exist, so assess the individual need rather than applying a blanket specialty-formula rule.
Distinguish renal solute load from formula water
Protein metabolism produces urea, and electrolytes also contribute to the solutes cleared in urine. Because urine cannot be concentrated without limit, a higher excretory solute load can require more urinary water at the same concentrating capacity. When available water is insufficient, this can increase dehydration risk. The 2005 Institute of Medicine water report supports this mechanism; it also describes a small study in which higher protein intake did not increase urine volume when water was freely available. A higher solute load therefore does not by itself establish dehydration or a fixed additional water dose. Review formula composition, all delivered water, losses, and renal function together.
Build the water prescription
Review formula free water, scheduled tube flushes, medication flushes, oral fluids, and intravenous fluids together. Count each source once, using the volume actually received. Compare that total with an individualized daily target to estimate supplemental water. Reassess fluid balance, ongoing losses, renal function, sodium status, and any fluid restriction; a change in formula volume or other intake changes the remaining requirement. Prescribe water delivery in amounts and at a pace suited to the patient and access route. A patency flush schedule does not by itself establish that hydration needs are met.
Account for each water source once
In a hypothetical water-budget exercise, 1,200 mL of formula labeled 80% water provides 960 mL of water. Add 300 mL of scheduled water flushes, 40 mL of separate medication water, and 100 mL of oral water: 1,400 mL total. Against a stated 1,500 mL daily target, 100 mL remains. These amounts are separate contributions, so do not count a medication flush again as a scheduled flush or add the entire formula volume a second time. Use what was actually delivered. The stated label and target are exercise inputs; this arithmetic does not establish a patient-specific water requirement or a safe flush schedule.
Reassess hydration signals in context
Inadequate fluid intake during tube feeding can contribute to hypernatremia. Rising blood urea nitrogen (BUN) and reduced urine output also warrant assessment: dehydration can raise BUN, but impaired kidney function can do so as well. Review formula water content, delivered feeding volume, flushes, medication fluids, other intake, losses, and renal status instead of diagnosing the cause from formula density or BUN alone. Tailor the correction to the patient; adding fluid without assessing the total intake and the risk of fluid accumulation can be inappropriate.
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Lesson
Medication Administration Through Enteral Access
Safe medication delivery requires a dosage-form review, absorption-site review, drug-specific feeding plan, and flush sequence for every administration.
- Do-not-crush formulations
- Drug and nutrient interactions
- Flush sequence
- Tube site and dosage form
Crushability, release, hazard
Gastric conditions and absorption site
Never mix into formula
Protect dose and tube patency
Review the dosage form before altering it
Do not crush extended-release, delayed-release, enteric-coated, sublingual, buccal, or hazardous products unless a trusted drug-specific source explicitly permits an alternative technique. Immediate-release tablets may be crushable, and some capsules may be opened, but each product must be checked. Select a compatible liquid or alternative route when possible.
Check liquids as carefully as tablets
A liquid oral formulation is not automatically suitable for a feeding tube. Both solid and liquid dosage forms can be incompatible, and drug or nutrient interactions can reduce effect or increase toxicity. Consult the exact product's labeling before choosing a formulation or altering it. Do not add a medication directly to the nutrition formula; an oral route designation alone does not establish tube compatibility.
Separate medications from formula and each other
Pause feeding for medication administration and tube flushing. Give each compatible medication separately, flushing before the first drug, between drugs, and after the final drug. Do not add medications directly to formula or combine different drugs in one syringe. Use a clean enteral syringe and the approved preparation instructions; the 2017 ASPEN safe-practice guidance recommends purified water for medication preparation and surrounding flushes. Choose flush amounts with the patient’s fluid needs and restrictions in mind. Restart feeding promptly after administration unless a drug-specific interaction or clinical condition requires a longer hold. A brief administration pause and a prolonged feeding-separation interval serve different purposes.
Manage interactions by mechanism
Calcium, magnesium, and iron in feeding products can chelate tetracyclines, fluoroquinolones, and levothyroxine, reducing bioavailability. Feeding can also reduce phenytoin exposure, while formula binding and vitamin K content can affect warfarin response. These are different mechanisms. Check the exact product's administration instructions and monitor the appropriate clinical endpoint or concentration; do not apply one medication's feeding interval to every drug.
Distinguish ciprofloxacin formulations
The oil-based ciprofloxacin oral suspension illustrates why a liquid is not automatically tube compatible: it can adhere to the feeding tube. The immediate-release tablet is the formulation described for crushing and mixing with water, with water flushing before and after administration. Verify the exact product's labeling and tube instructions before selecting it. This formulation distinction does not remove the separate absorption interaction with calcium, magnesium, or iron in feeds, and it does not authorize crushing an extended-release tablet.
Reconcile warfarin with the feeding plan
Feeding products can bind warfarin and lower its availability; their vitamin K content can also lower the INR. Keep vitamin K exposure consistent, review changes in formula and delivery schedule, and monitor INR rather than changing the dose from the formula name alone. The feeding-separation plan described here for warfarin is one hour before and one hour after administration. Coordinate that plan with the medication order and nutrition delivery; do not copy it to another drug.
Monitor phenytoin when feeding changes
Enteral feeding can reduce phenytoin absorption and produce subtherapeutic concentrations. Review the formulation, actual administration, feeding schedule, seizure control, and serum phenytoin concentration when exposure changes. Do not respond to a falling concentration with an automatic dose increase before checking delivery and interactions. Phenytoin also has dose-related toxicity and substantial protein binding, so concentration interpretation must account for the patient's clinical state and albumin, kidney, and liver function. A phenytoin-specific separation plan may hold feeding for one to two hours before and after the dose. Confirm the actual product's administration instructions and prescribed plan; a warfarin schedule does not establish a phenytoin schedule.
Respect the tube tip
Identify and document the tube’s entry point and distal tip when reviewing a medication order. Jejunal delivery bypasses gastric conditions and may bypass a drug’s primary absorption site, so an oral or gastric administration method cannot automatically be transferred to a jejunal tube. Review the exact drug, dosage form, dissolution requirements, and administration site; obtain a suitable formulation or alternative route when needed. Sorbitol-containing or highly osmolar liquids can contribute to gastrointestinal symptoms, especially with small bowel delivery. Follow product-specific dilution instructions rather than assuming every liquid is compatible, and count preparation and flush water in the fluid plan.
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Lesson
Monitoring and Complication Prevention
Tolerance is a clinical pattern. Integrate delivered volume, symptoms, examination, stool, fluid balance, glucose, electrolytes, access integrity, and infection risk.
- Aspiration prevention
- Diarrhea and intolerance
- Tube obstruction and displacement
- Refeeding and metabolic monitoring
Assess rate, disease, infection, drugs
Watch refeeding and hydration
Migration, clogging, leakage
Audit holds, pump, preparation
Prevent aspiration with a bundle
For critically ill adults receiving gastric enteral nutrition, use coordinated aspiration precautions: elevate the head of the bed 30 to 45 degrees when clinically feasible, confirm the intended tube position before use and reassess when migration is suspected, and minimize unnecessary sedation while maintaining appropriate comfort and care. Assess gastric emptying and the patient's ability to protect the airway; consider postpyloric access for high aspiration risk and continuous delivery when gastric boluses are not tolerated. The 2016 SCCM/ASPEN guideline advises against adding blue dye or methylene blue to formula as aspiration markers. A single residual volume does not establish aspiration or normal tolerance. Apply age- and condition-specific positioning guidance rather than transferring this adult ICU bundle to infants.
Use gastric residuals selectively
The 2016 SCCM/ASPEN adult ICU guideline advises against routine gastric residual volume monitoring and against automatically holding feeding for a residual below 500 mL when other intolerance signs are absent. Values in the 200 to 500 mL range still warrant aspiration-risk assessment and preventive measures. This is not a universal safety cutoff: the 2023 ASPEN practice tool, in its vasopressor-administration guidance, describes a reasonable hold above 300 mL based on limited, low-quality evidence. Follow the applicable clinical setting and institutional protocol rather than combining these thresholds into one rule. Assess residual trends with vomiting, distention, pain, hemodynamics, stool, available imaging, and aspiration risk. Neither a value below 500 mL nor omission of routine residual checks establishes normal tolerance or removes the need for clinical monitoring.
Find the cause of diarrhea and clogging
Assess diarrhea with the clinical examination, stool pattern, fluid and electrolyte status, and a review of medications, infection, formula composition, delivery, and contamination. Antibiotics, laxatives, and sorbitol-containing preparations are possible contributors; formula osmolality alone does not establish the cause. The 2016 SCCM/ASPEN guideline advises against automatically interrupting feeding for diarrhea in critically ill adults while evaluating its cause. For an uncomplicated clogged tube, check for kinks and follow the institutional declogging procedure. Warm water with gentle back-and-forth syringe movement is the initial approach for trained staff. Avoid acidic beverages, forceful pressure, and improvised objects. If water fails, escalate through the approved protocol rather than improvising an enzyme mixture or device.
Monitor delivery and metabolic safety
Compare the prescribed regimen with the formula and water actually delivered, including interruptions and their causes. Track weight trend, intake and output, hydration and volume status, gastrointestinal symptoms, glucose, sodium, potassium, magnesium, phosphate, and kidney function. Set the monitoring interval according to acuity, the stage of feeding, and clinical changes rather than applying one schedule to every patient. For patients at refeeding risk, check and treat potassium, magnesium, and phosphate abnormalities during cautious initiation; severely low levels warrant delaying initiation or calorie increases until corrected. Rapid falls or levels that are difficult to correct require prompt reassessment, electrolyte treatment, and adjustment of energy delivery. Inspect tube position, patency, and the access site; report new pain, excess leakage, redness, or swelling. Reduce contamination risk with hand hygiene, aseptic handling, and manufacturer and facility instructions for preparation, storage, hang time, and equipment changes. Do not top off a feeding container or reuse equipment labeled for single use. Fever or diarrhea warrants clinical assessment of contamination and other possible causes rather than a diagnosis based on a handling error alone.
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Module practice
Check the connections.
Each attempt draws 10 questions from the complete 108 question bank.
Each attempt draws a fresh set and rearranges the answer choices.
References
Current clinical foundation.
Core source material was synthesized with the following contemporary guidance. Verify local policy and current guidance before applying clinical information.
- Institute of Medicine. Dietary Reference Intakes: Water, 2005, Chapter 4
- ASPEN practice tool: enteral nutrition in patients with fat malabsorption, 2023
- ASPEN practice tool: hypoallergenic formula composition and pediatric indications, 2023
- McGrath et al. AuSPEN clinical consensus on jejunal tube feeding in children, 2024
- FDA. Tips for Health Care Providers to Reduce Medical Device Misconnections
- FDA. Enteral Small-Bore Connector Misconnection Guidance, 2015
- SCCM/ASPEN. Adult Critical Care Nutrition Guideline, 2016
- ASPEN. Enteral Nutrition Indications in Critical Illness Practice Tool, August 2023
- ASPEN. Safe Practices for Enteral Nutrition Therapy, 2017
- ASPEN. Adult Critical Care Nutrition Guideline, 2022: Selected Nutrition-Support Questions
- ASPEN. Consensus Recommendations for Refeeding Syndrome, 2020
- FDA medical device connector safety resources