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Questioning common nursing practices: What does the evidence show?


To meet the needs of patients and their families, healthcare practice must be based on current research and the best evidence. Many definitions of evidence-based practice (EBP) exist. All share similar elements—critical review of current research and examination of other forms of evidence, including national and local guidelines for practice, practice consensus documents, benchmark data, quality improvement studies, and population or patient perspectives.

To embrace EBP, nurses must critically examine multiple forms of evidence. No longer is it acceptable to resist changing a practice simply because the task or skill in question “has always been done that way.” To move nursing practice forward, we must question practices and continually review available evidence to ensure a given practice benefits patients. By doing this, nurses can lead healthcare reform through embracing EBP that results in better care. This article discusses the evidence on several common nursing practices and makes recommendations to help improve outcomes.

Assessing pain in nonverbal adults

Pain is a subjective experience, defined by whatever the patient says it is and existing whenever the patient says it exists. It’s best assessed by patient self-report, which clinicians should elicit routinely and repeatedly, and then implement appropriate interventions.

Assessing and managing pain is a nursing care priority for all patients—even those who can’t communicate verbally. Obvious challenges arise when a patient can’t give a self-report due to severe illness, altered cognition, or use of equipment (such as a mechanical ventilator) that inhibits communication. We now have a large body of evidence to guide nursing management of pain, including pain in nonverbal adults. To meet the pain-management needs of nonverbal adults, assess frequently for behavioral changes, anticipate pain after certain procedures, use patient surrogate reporting, and administer analgesic trials (and evaluate the patient’s response).

Current evidence shows the most effective way to assess nonverbal adults for pain is to follow an evaluation hierarchy. (See Hierarchy of pain assessment techniques by clicking the PDf icon above). In nonverbal patients, pain assessment relies less on vital-sign assessment and more on observing behaviors, checking for potential causes of pain, and eliciting information from the patient’s surrogates. Vital-sign changes are misleading as a primary indicator of pain because they may stem from underlying physiologic conditions, hemodynamic changes, and medications. Only limited evidence suggests vital-sign assessment alone should be used to gauge pain. Nonetheless, vital-sign changes may suggest the need for further assessment for pain or other stressors. More importantly, absence of vital-sign changes doesn’t indicate absence of pain.

You can use several valid and reliable observational and behavioral scales to aid pain assessment in nonverbal patients. But be aware that these scales don’t evaluate pain intensity, especially in patients receiving sedatives.
Patients with advanced dementia require additional behavioral observation. As dementia progresses, self-reporting ability
decreases. EBP suggests nurses should assess for pain and intervene appropriately in patients (including dementia patients) with conditions that typically cause pain, such as chronic arthritis, low back pain, and neuropathies. Pain-related behaviors or indicators may include changes in facial expression, verbalizations and vocalizations, changes in activity patterns or routines, rubbing a body part, and altered interpersonal interactions (such as agitation, restlessness, and combativeness). The City of Hope Pain and Palliative Care Resource Center offers a comprehensive list of resources and valid, reliable tools for assessing pain in elderly patients with cognitive impairment. (Visit

Implications for practice

The potential for unrelieved, unrecognized pain is greatest in patients who can’t verbalize their discomfort. No patient’s pain should go untreated during an acute hospitalization. To meet patients’ needs, nurses should use valid, reliable pain assessment tools. Current best evidence suggests that when providing care to patients who can’t self-report pain, clinicians should assess pain frequently using a behavioral pain scale and information obtained from surrogates, assess for subtle changes in observed behaviors, and initiate an analgesic trial.

Assessing gastric residual volume

Why do nurses assess gastric residual volume (GRV)? Many believe the purpose is to gauge the patient’s tolerance of tube feeding and risk for aspiration. But the evidence shows that checking GRV doesn’t provide reliable information on tube-feeding tolerance, aspiration risk, or gastric emptying. In fact, it may lead to patient underfeeding. Studies show the most common reasons for stopping enteral feeding include high GRV, supine patient positioning for procedures or nursing care, diarrhea, and preprocedural protocols. Little evidence supports stopping or withholding tube feeding to reposition patients.

Similarly, the value of assessing GRV in evaluating tube-feeding tolerance isn’t well defined, and scant evidence exists to guide nurses in obtaining an accurate GRV. Most guidelines suggest using a large-volume syringe (60 mL) to aspirate fluid effectively, as smaller-volume syringes may collapse the tube. Likewise, it’s easier to obtain GRV from larger-bore tubes (14 to 16 French) than smaller-bore tubes (8 to 12 French). Also, placing a tube near the gastroesophageal junction promotes aspiration of contents. Evidence also questions the accuracy of GRV obtained from postpyloric tubes as these tubes have a small diameter, and in this part of the GI system, contents are propelled forward, making accurate GRV measurement difficult.

What’s more, we have little evidence to define how much volume constitutes a high GRV. Typically, at any given time the stomach contains approximately 180 mL of fluid (such as saliva and gastric secretions). When assessing GRV, clinicians should include this native
volume in interpreting the volume extracted from the gastric tube.
Current evidence shows high GRV ranges from 150 to 500 mL of aspirate. But a single elevated GRV requires no action—only ongoing monitoring. Caregivers shouldn’t stop enteral nutrition on the basis of a single high GRV, although serial high GRVs may warrant additional interventions, such as consideration of prokinetic agents to promote gastric motility.

Using an evidence-based nutritional protocol can minimize unnecessary withholding of enteral feedings and help meet patients’ nutritional needs more reliably. If serial GRV measurements are high, explore the cause of enteral-feeding intolerance (such as bloating, abdominal pain, or changes in patient condition). To avoid underfeeding, once the patient can tolerate tube feedings, question the need to keep checking GRV.

Likewise, using GRV to assess aspiration risk isn’t evidence based. Research has found patients may aspirate with a GRV of 5 to 500 mL, and in many cases aspiration is clinically silent. Patient characteristics, not GRV assessment, increase the aspiration risk. The risk rises with an altered level of consciousness, critical illness, and mechanical ventilation. Interventions to reduce risk include keeping the head of bed above 30 degrees, evaluating the need for agents that increase gastric motility, and considering postpyloric enteral feeding if intolerance persists.

On the other hand, GRV monitoring can be used to assess gastric tube location. After radiography confirms accurate gastric-tube placement, GRV assessment (including evaluation of aspirate appearance and changes) may aid ongoing tube-placement assessment.

Implications for practice

GRV assessment isn’t a reliable way to assess tube-feeding tolerance or aspiration risk. Maximizing nutrition is essential to patient health. Meeting patients’ nutritional needs hinges on using evidence-based enteral feeding protocols that guide GRV assessment frequency, prokinetic agents, and other variables of intolerance. Assessing aspiration risk should be driven by severity of illness and interventions that compromise the gag reflex.

Nurses must challenge the current practice of using GRV as a primary assessment variable to determine tube-feeding tolerance and aspiration risk. EBP suggests that relying on GRV alone may adversely affect patient outcomes.

Using the Trendelenburg position to treat hypotensive episodes

In the late 1800s, Friedrich Adolf Trendelenburg placed patients supine with the head of the bed tilted 45 degrees downward to aid visualization of abdominal organs for surgical procedures. Today, some clinicians use this position, now called the Trendelenburg position, to treat hypotensive episodes. They believe this position shifts intravascular volume from the lower extremities and abdomen to the upper thorax, heart, and brain, improving perfusion to these areas.

But as far back as the 1960s, researchers found undesirable effects of the Trendelenburg position, including decreased blood pressure, engorged head and neck veins, impaired oxygenation and ventilation, increased aspiration risk, and greater risk of retinal detachment and cerebral edema. Evidence shows that while this position shifts fluid, it adversely engorges the right ventricle, causing it to become dilated, which further reduces cardiac output and blood pressure. It also impairs lung function by compromising pulmonary gas exchange. Abdominal contents shift upward, increasing pressure on and limiting movement of the diaphragm and reducing lung expansion. Lung compliance, vital capacity, and tidal volumes decrease while the work of breathing increases. The result is impaired gas exchange—hypercarbia and hypoxemia. Evidence also suggests that when obese patients are placed in Trendelenburg position, lung resistance increases significantly and pulmonary gas exchange worsens.

Implications for practice

The Trendelenburg position has little, if any, positive effect on cardiac output and blood pressure. It impairs pulmonary gas exchange and increases the aspiration risk. The evidence doesn’t support its use to treat hypotension. However, evidence-based practice does support elevating the lower extremities—without using a head-down tilt position—to mobilize fluid from the lower extremities to the core during hypotensive episodes. Sometimes called a modified Trendelenburg position, this position has been found to support blood pressure without the negative consequences of the traditional Trendelenburg position.

Ensuring that healthcare practices are based on the best evidence can improve patient safety. To safely and effectively manage acutely ill patients, clinicians must evaluate traditional practices and systems.

Visit for a complete list of references.

Mary Beth Flynn Makic is a research nurse scientist in critical care and an associate professor (adjoint) at the University of Colorado in Aurora. Carol A. Rauen is an independent Clinical Nurse Specialist and education consultant as well as a staff nurse in the emergency department at the Outer Banks Hospital in Nags Head, North Carolina. Kathryn T. VonRueden is a Clinical Nurse Specialist at the R Adams Cowley Shock Trauma Center at the University of Maryland Medical Center in Baltimore and an assistant professor at the University of Maryland School of Nursing.

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