Until recently, healthcare practitioners have answered questions about clinical practices with their best guesses, intuition, and tradition. But evidence-based practice (EBP) compels us to use solid scientific evidence instead, and to base nursing protocols on this evidence. As defined by the Institute of Medicine, EBP is the integration of the best research, clinical expertise, and patient values when making decisions about patient care.
This article discusses three commonly performed acute-care nursing practices that are not based on evidence:
• instilling normal saline solution (NSS) into the patient’s endotracheal tube before suctioning
• turning critically ill patients manually every 2 hours
• relying on the Glasgow Coma Scale (GCS) alone for routine neurologic assessment.
When these practices were introduced, no research supported them. Yet many practitioners keep performing them, despite recent research that suggests they should be changed. This article examines these three practices critically.
Instilling NSS before ET suctioning: Helpful or harmful?
For years, nurses and respiratory therapists have been taught to instill 5 ml of sterile NSS into a patient’s endotracheal (ET) tube before suctioning. According to the traditional theory, this practice decreases mucosal viscosity, eases secretion removal, and improves oxygenation. Although at one time the theory seemed to make sense, research from the past 20 years shows it’s incorrect. Here’s what current research (primarily involving adults) tells us:
• Instilling NSS before suctioning decreases oxygen saturation and forced expiratory volume (a sign of bronchospasm).
• This practice may increase the risk of hospital-acquired pneumonia (HAP), as bacteria from the nurse’s thumb may contaminate the rim of the NSS vial when the vial top is popped off.
• Successful humidification requires small particle size in the form of ultrasonic nebulization, not bolus administration.
• No studies show that NSS instillation yields benefits. On the contrary, studies prove that this practice can lower oxygenation levels and increase the risk of HAP.
Consequently, the current EBP recommendation is not to instill NSS during routine ET suctioning.
Mobility matters: Are we moving critically ill patients enough?
For years, nurses have recognized that proper patient positioning helps prevent skin breakdown, mobilizes secretions, and provides comfort. But many nurses fail to consider the impact of various positioning strategies on pulmonary gas exchange, ventilator weaning outcomes, and prevention of muscle deconditioning in intensive care unit (ICU) patients.
A busy healthcare environment can pose a challenge to frequent repositioning—especially with critically ill patients. One prospective longitudinal observational study of a critical care unit found that over an 8-hour period, only 2.7% of observed patients experienced position changes every 2 hours, and more than half were supine for 4 to 8 hours.
The solution is to improve nurses’ awareness of the importance of proper positioning on both short- and long-term patient outcomes. If we don’t pay enough attention to this care activity, it’s likely to be neglected. Evidence shows that for many critically ill patients, turning every 2 hours isn’t frequent enough to preserve the lung’s oxygenating ability or prevent HAP. When a patient is at risk for HAP or ventilator-acquired pneumonia (VAP), continuous lateral rotation therapy (CLRT) should be used.
Research on the positioning of critically ill patients tells us that:
• for patients with consolidated pneumonia in one lung, positioning with the “good” lung down improves oxygenation. The goal is to match alveoli with perfused capillaries. Despite mechanical restriction in the downward position, the healthy lung has enough functioning alveoli to match gravity-dependent perfusion and thus promote effective gas exchange.
• mobilizing intubated patients progressively from a dangling position to standing and then to walking is safe.
• breathing and oxygenation improve at higher elevations of the head of the bed, as long as the elevation is hemodynamically tolerable.
• during ventilator weaning, patients with large abdomens seem to breathe more easily and have larger spontaneous tidal volumes when the head of the bed is elevated 45 degrees and the bed is in reverse Trendelenburg position.
• prone positioning improves oxygenation, but has not been shown to affect mortality risk. Consider prone positioning if conventional strategies for lung recruitment have failed.
• in ICU survivors, the deconditioning that occurs during hospitalization can lead to functional physical limitation that proves to be a major complication 1 year later.
Barriers to mobility
Hemodynamic instability is the main reason why critically ill patients stay in the supine position for extended periods. When you consider the factors that affect tolerance of position changes, you realize these patients are clearly at risk for such negative effects as hypotension. After a change in the body’s gravitational plane, the cardiovascular system normally tries to adjust in two ways:
• The shift in plasma volume may send messages to the autonomic nervous system telling it to change vascular tone.
• An inner ear or vestibular response affects the cardiovascular system.
Critically ill patients commonly have poor vascular tone, a dysfunctional autonomic feedback loop, or low cardiovascular reserve. Also, they’ve established equilibrium in a single position over time. For those who become hemodynamically unstable after manual turning, the solution is to gradually retrain them, using CLRT, to tolerate a position change.
Clearly, we don’t have all the answers on when and how often these patients should be turned, but we do know that ensuring patient mobility makes a difference. The evidence shows that making mobility a core component of care reduces patients’ feelings of powerlessness, promotes secretion management, helps prevent muscle wasting, improves gas exchange, and decreases the incidence of atelectasis and VAP.
Glasgow Coma Scale: Is it enough for a comprehensive neurologic assessment?
For decades, we’ve known that neurologic assessment is the best way to detect onset or progression of brain injury. Assessment findings reflect pathophysiology and response to both progression of injury and therapeutic interventions. Optimally, earlier identification of responses to or progression of injury and to therapeutic interventions should guide the direction of care.
The GCS was introduced in 1974 as a way to standardize patient evaluation and improve communication among healthcare workers about a patient’s neurologic status. Over the last few decades, the GCS has been used extensively and has been incorporated into many critical care flowsheets, emergency medicine documentation forms, and other clinical grouping systems. It’s widely used to predict neurologic and clinical outcomes.
The GCS assigns a separate numerical value to a patient’s response in three spheres—motor response, verbal response, and eye opening. Such responses reflect how movement is stimulated in the extremities, the patient’s ability to interact, and the brain’s arousal mechanisms. Each response is scored individually; then the three scores are totaled. The lowest total score is 3; the highest is 15, which indicates the patient is alert; oriented to person, place, and time; and able to follow simple commands.
Where the GCS falls short
Although the GCS has distinct benefits, scoring hinges on the patient’s ability to respond to stimulation and interact with the clinician. The GCS doesn’t assess brainstem reflexes, and has limited value for patients with deep sedation, neuromuscular blockade, intubation and controlled ventilation, and some psychiatric or metabolic disorders.
A patient receiving deep sedation and analgesia has a drug-induced depression of consciousness. In this case, relying solely on the GCS may lead to an incomplete neurologic evaluation.
When given in appropriate doses, neuromuscular blocking agents produce a state of skeletal muscle relaxation in which the patient could be awake and responsive, yet appear to be otherwise because the drug prevents a response to stimulation. Depending on the GCS in this case is inadequate.
Also, the GCS doesn’t uniformly assess verbal response in intubated patients. Tracheal intubation and controlled ventilation interfere with verbal response to the GCS, as the artificial airway impedes speech. Thus, a fully awake and interactive patient may have a misleadingly low verbal response score. To address this, clinicians should focus on arousal, consciousness, and patient interaction; if the patient is interactive and communicative, document this fact accordingly.
Such disorders as delirium, catatonia, and psychogenic coma also can interfere with valid GCS determination. Delirium is a cognitive disorder; catatonia and psychogenic coma can occur in certain psychiatric disorders. The GCS may not even detect these states.
To compensate for these shortcomings, other neurologic assessment tools have been developed. For instance, the FOUR (Full Outline of UnResponsiveness) Score scale evaluates eye response, motor response, brainstem reflexes, and respiration. Easy to use, it provides information the GCS doesn’t, yielding a more comprehensive picture of a patient’s degree of responsiveness. In particular, it recognizes such disorders as locked-in syndrome (in which the patient is aware but unable to respond except by tracking or blinking). It also can help predict in-hospital mortality.
For optimal neurologic evaluation, the best EBP recommendation is to use the GCS with greater accuracy and consistency—while using additional neurologic assessment tools that yield information that the GCS alone can’t.
More evidence means better outcomes
All nurses want to provide the best possible patient care. To do this, we must change our practices when the research shows that such a change would better serve patients. Nursing practice is always evolving. We must constantly ask ourselves whether we’re providing the best care possible given the current available evidence. If the answer is no, we must work to change that practice and implement protocols and standards that will bring greater patient benefit.
Ackerman M, Mick D. Instillation of normal saline before suctioning in patients with pulmonary infections: a prospective randomized controlled trial. Am J Crit Care. 1998;7:261-266.
Raymond S. Normal saline instillation before suctioning: helpful or harmful? A review of the literature. Am J Crit Care. 1995;2:467-473.
Bailey P, Thomsen GE, Spuhler V, et al. Early activity is feasible and safe in respiratory failure patients. Crit Care Med. 2007;35:139-145.
Vollman K. Ventilator-associated pneumonia and pressure ulcer prevention as targets for quality improvement in the ICU. Crit Care Nurs Clin North Am. 2006;18:453-467.
Glasgow Coma Scale
Arbour R. Intracranial hypertension: monitoring and nursing assessment. Crit Care Nurse. 2004;24(5):19-34.
Teasdale G, Jennett B. Assessment of coma and impaired consciousness: a practical scale. Lancet. 1974;2:81-84.
Visit www.AmericanNurseToday.com/journal for a complete list of selected references.
Carol A. Rauen is an Independent Clinical Nurse Specialist and Education Consultant and a staff nurse at the Washington Hospital Center in Washington, D.C. Kathleen Vollman is a Clinical Nurse Specialist, educator, and consultant with Advancing Nursing, LLC in Northville, Mich. Richard B. Arbour is a Clinical Nurse Specialist at Albert Einstein Medical Center in Philadelphia, Pa. Marianne Chulay is a consultant in clinical research and critical care, as well as coeditor of AACN Advanced Critical Care, based in Gainesville, Fla.