Are we doing what is best for our patients with the current evidence available to us?Nursing has deeply rooted traditions. As far back as Florence Nightingale in the 19th century, nurses prided themselves on patient advocacy, infection control (before germ theory), and physical care of the entire body, not limiting the focus to management of disease or signs and symptoms.1 These early roots established the philosophy of nursing. Nurses labeled what they do as caring or the art of nursing.Critical care nurses find themselves in a unique situation. We have our feet deeply rooted in the art of nursing. Yet our hands and minds reach for the scientific basis that our highly technical, physiological, and pharmacological specialty requires. To base our practice on science, we must use research to answer questions, establish protocols, and promote critical thinking and decision making at the bedside. Doing so requires us to be willing and able to change practices, regardless of the tradition and commonly held beliefs, if validated, reliable, and useful evidence leads to such change. Nurses are at the forefront of evidence-based approaches.2The Institute of Medicine defines evidence-based practice (EBP) as “the integration of best research, clinical expertise, and patient values in making decisions about the care of individualized patients.”3 Research findings are a collection of facts. They become evidence when the findings are relevant and useful in particular clinical circumstances.4 Using research to guide clinical decision making is a shift in culture from basing decisions on opinion, past experiences, and precedents to basing decisions on science, research, and evidence.5 The Agency for Healthcare Research and Quality published Making Health Care Safer: A Critical Analysis of Patient Safety Practices.6 This document outlines 79 evidence-based practices and targets related to patient safety. The 11 recommendations with the strongest research support have a direct connection to critical care practice (Table 1).In this article, we cover 7 evidence-based practice (EBP) recommendations that clinicians should consider implementing into their practice. Much of this research is not new and has met with resistance at the bedside despite clear evidence that it represents best practice. We also address the traditional approach and offer recommendations for implementing the changes. Marianne Chulay addresses instillation of normal saline (physiological salt solution) with endotracheal suctioning and verification of nasogastric tube placement. Elizabeth Bridges reviews the current evidence and recommendations for accurate measurement of blood pressure and selection of electrocardiography leads. Kathleen Vollman delineates the research and recommendations for patients’ positioning and mobility. Richard Arbour discusses use of the Glasgow Coma Scale in neurological assessment and management of intracranial hypertension.Most hospital policies and procedures for management of artificial airways include instilling 5 to 10 mL of normal saline before endotracheal suctioning is done.7 This nursing and respiratory therapy routine was advocated as a way to improve oxygenation and removal of secretions by thinning thick secretions and stimulating coughing to assist with mobilization of secretions. Although instillation of normal saline is a long-practiced suctioning intervention, no research has ever documented the benefit of this practice, and some researchers have found the practice potentially harmful.In most experimental studies8–13 on the effect of instillation of normal saline before endotracheal suctioning, oxygen saturation or PaO2 was evaluated as the primary end point; in only a single study14 was mixed venous oxygenation evaluated. In these studies, oxygen saturation was significantly lower with instillation of saline than with no instillation of saline,8–10 or the results of the 2 methods (saline vs no saline) did not differ.11,12 In no studies to date did instillation of normal saline before suctioning improve oxygen saturation compared with suctioning without instillation of saline.An interesting finding in studies8–13 that showed decreases in oxygenation after instillation of saline before suctioning was that return to baseline oxygenation levels did not occur until at least 3 to 5 minutes after the suctioning procedure was finished. Although the decrease in oxygenation with instillation of normal saline may not be dramatic, it is far from a transient derangement.Several researchers9,12,15,16 have attempted to determine if more secretions are removed with suctioning when normal saline is instilled than when suctioning is done without instillation of saline. By weighing the volume of secretions removed during suctioning, the researchers hoped to quantify differences between the 2 methods of suctioning. However, in all but a single study, researchers did not take into account the weight of the saline instilled in their calculations, creating a serious flaw in the experimental design of the study and negating the results. In the one, small study16 (N = 12) in which the weight of the saline was taken into account, serious flaws in the study design (lack of randomization of the interventions) make the results invalid.Although an alleged benefit of instillation of saline is improvement in removal of secretions, to date no adequately reported scientific studies support that contention. This lack of research is no doubt partly due to the methodological issues associated with the measurement of secretion volumes in clinical studies, meriting further research to determine the best way to quantify removal of pulmonary secretions.17Although clinicians often believe that instillation of normal saline “thins” thick pulmonary secretions, no research has ever shown that this belief is correct. In fact, experts in airway humidification long ago pointed out the fallacy of this notion, because small-particle humidification, not administration of a fluid bolus, is required to achieve any semblance of incorporation of fluid into thick secretions.18(p504) And even small-particle humidification falls short of actually “thinning” secretions noticeably. Experts18–20 recommend systemic hydration to decrease the viscosity of pulmonary secretions, because thick secretions reflect dehydration of mucous glands. The topical application of a 5- or 10-mL bolus of normal saline to thick mucus will not lead to incorporation of the saline into the mucus.21For clinicians who believe that normal saline thins secretions, try the following experiment to see for yourself what impact administration of a bolus of normal saline has on thick secretions.22 The next time you use suctioning, use a mucus trap to collect some of the thick secretions. Then, insert 5 to 10 mL of normal saline into the trap and observe how the saline remains separate from the mucus, even after vigorous shaking. Let the mixture sit a while to validate that even with exposure over time, the mucus and fluid remain separate from each other. If normal saline cannot thin thick secretions in a mucus trap with really vigorous shaking, it certainly cannot do it in a patient’s lungs.In 2 studies,23,24 researchers reported that instillation of normal saline may place the patient at risk for hospital-acquired pneumonia. Rutula et al23 found that the rims of the individual-dose vials of normal saline were often contaminated with bacterial organisms just before insertion of the fluid into the endotracheal tube. On the basis of the type of bacterial organisms found on the rim, they hypothesized that the contamination of the vial had occurred when clinicians had “popped” the top off the vial with a thumb. Although the researchers23 did not evaluate infection of patients, introduction of bacterial organisms because of contamination during administration of the fluid is certainly theoretically possible.In a laboratory study24 of endotracheal tubes that had recently been removed from patients in the intensive care unit (ICU), the amount of bacteria evacuated from the end of endotracheal tubes was 5 times greater when a bolus of normal saline was administered through the endotracheal tube before the suction catheter was introduced than when a suction catheter alone was passed through the endotracheal tube. The investigators24 hypothesized that a similar high load of bacterial contamination of the pulmonary system might occur when normal saline is instilled into the endotracheal tube during suctioning. The instillation of normal saline may act as a vehicle to “wash” the bacteria that normally cling to the inner aspects of the artificial airway into the lung, potentially leading to infection. Hagler and Traver24 did not evaluate clinical infection; however, they pointed out that instillation of saline before endotracheal suctioning may have some unintended outcomes.Although the normal saline that is instilled should be sterile and without preservatives, isolated cases of outbreaks of bacterial pneumonia due to vials of normal saline contaminated during the manufacturing process have been reported.25,26In several reports7,27–29 since 1996, researchers have described how often nurses and respiratory therapists instill normal saline before endotracheal suctioning. In most of the studies,7,27,29 25% to 33% of nurses routinely or frequently instilled normal saline before suctioning. Twice as many respiratory therapists as nurses instilled normal saline.7,29 In a 1996 survey,28 pediatric critical care nurses almost universally instilled normal saline before doing suctioning. Most of the hospitals surveyed indicated that instillation of normal saline before endotracheal suctioning was included in the hospital’s policy/ procedure for suctioning.7Resources for EBP recommendations are unanimous in their recommendation that instillation of normal saline should not be performed as a routine step with endotracheal suctioning. From reviews19,20,30,31 of the literature on the topic to national guidelines32–34 for EBP procedures, experts in airway management practices reiterate that despite some practitioners beliefs, no credible, scientific information supports the routine use of instillation of normal saline with endotracheal suctioning. In addition to the lack of any theoretical benefit, no studies have shown that instillation of normal saline is beneficial to patients, and some researchers have found it detrimental.The incidence of inadvertent placement of gastric or postpyloric tubes into the lungs, instead of the gastrointestinal system, with blind insertion at the bedside is not clearly known. Most of the information about inadvertent placement has come from case reports.35,36According to 2 research studies done to determine the sensitivity and specificity of capnography for detecting inadvertent pulmonary placement of gastric and postpyloric tubes, the incidence of pulmonary placement was 11% (11 of 100 attempts) when verified by chest radiography37 and 20% (4 of 20 attempts) when verified by carbon dioxide waveforms.38 Even if the actual clinical incidence is lower than observed in these limited studies, the complications associated with a feeding tube placed in the lung can be lethal; thus, a 100% effective method for verifying proper location of such tubes is needed.A variety of methods have been advocated to detect when a gastric or postpyloric tube has been introduced into the pulmonary system: auscultation during air insufflation through the tube, pH testing of aspirated fluid, visual inspection of aspirated fluid, detection of carbon dioxide in the tube, and radiographic tube verification.Auscultation over the gastric abdominal area during rapid insufflation of air into the distal end of a gastrointestinal tube is commonly performed after a tube is inserted. Research on air insufflation has never documented that this technique is accurate for identifying inadvertent intubation of the lungs. Numerous case reports of documented inadvertent pulmonary intubation despite auscultation over the gastric area of air during insufflation, though, have been published.36,39,40 In the early 1990s, researchers found that air insufflation with auscultation over the gastric area could not be used to predict the inadvertent placement of a gastric tube into the lungs.39 Because of the proximity of the lungs and stomach, it is not surprising that the sounds created by air insufflation through the tube could easily be transmitted to adjacent areas, causing clinicians to err in determining proper tube placement.Another technique that has been advocated over the years to identify inadvertent pulmonary intubation with gastric tubes is measuring the pH of fluids aspirated immediately after tube placement.41,42 It was hypothesized that because pulmonary secretions have an alkaline pH and gastric contents have an acidic pH, this simple bedside procedure could allow quick identification of tube location. Because a variety of situations can alter the pH of the gastric contents from acid to alkaline (drugs that change gastric pH, enteral feeding) and such situations are common in critically ill patients, the usefulness of this technique is limited. The outcome of pH testing is helpful only if the fluid tested is acidic, thus verifying gastric placement. If the fluid is alkaline, the gastric contents may be alkaline or the tube may be in the lung. Because of the lack of specificity of the pH technique and the numerous situations and conditions that lead to alkaline gastric contents, experts36,43–45 no longer advocate the use of pH testing to verify tube location.Visual inspection of the color of fluid aspirated from the tube has been advocated as a method to differentiate gastric fluid (green, dark yellow) from pulmonary fluid (white, light yellow). In the only study46 in which visual inspection of fluid was evaluated as a way of determining gastric or pulmonary location of the tube, visual inspection was a poor predictor of tube location. Similar to gastric pH, the colors of gastric and pulmonary secretions are altered by a variety of conditions, making development of a standard difficult.Most recently, in several small studies,37,38,47–51 investigators evaluated the use of devices to measure the presence of carbon dioxide in the tube as a way to determine if the lungs have been inadvertently entered. Because carbon dioxide is present only in exhaled pulmonary gases and not in the gastric contents, this technique may be helpful in differentiating between the 2 locations. In studies37,38,47–50 in which end-tidal carbon dioxide monitors or disposable, color-indicator carbon dioxide devices were connected to the gastrointestinal tube during insertion, detection of carbon dioxide with the devices allowed successful detection of gastric tubes that had been placed in the lungs. In all but a single study,51 no instances of false identification of pulmonary placement were noted.37,38,47–50 The results of these studies show promise for finding a bedside technique that allows accurately detection of inappropriate pulmonary intubation. Because of the consequences of missing an incorrect placement of a gastric tube, additional studies are need to validate carbon dioxide detection techniques in larger and more diverse populations of patients and in a variety of clinical situations. Of particular interest is the ability of multiple caregivers to correctly interpret the color indications displayed by the disposable carbon dioxide device and to determine if fluid obstruction in the gastrointestinal tube and/or contamination of the carbon dioxide indicator affects the accuracy of the device.At this time, national guidelines and expert opinion indicate that the best method for confirming the location of blindly inserted gastrointestinal tubes is chest radiography.36,43–45,52,53 The radiopaque marker on each tube makes radiographic detection of inadvertent pulmonary placement clear, because the tube marker is easily seen by a radiologist in the right or left main bronchus, structures easily discerned on a chest radiograph.Use of radiography to validate placement of small-bore gastrointestinal tubes is a clinically common policy in many facilities because inadvertent pulmonary intubations are thought to be more common with this type of tube. However, in a study by Burns et al,50 the incidence of pulmonary intubations did not differ between large- and small-bore gastric tubes. At this time, national guidelines recommend that proper placement of gastric tubes should be confirmed by radiographic means.In addition to the national guidelines54 for blood pressure measurement, a growing body of evidence supports specific procedural techniques that will improve the accuracy and reliability of noninvasive and invasive measurement of arterial blood pressure.55The American Heart Association recommendations for correct sizes of blood pressure cuffs are summarized in Table 2. Selection of the appropriate cuff size is important because a cuff that is too small yields an overestimation of blood pressure and a cuff that is too large yields an underestimation of blood pressure.56As with intra-arterial blood pressure monitoring,57–59 the appropriate reference level for noninvasive measurement of blood pressure is the heart54 (Figure 1). Blood pressure will be overestimated if the arm is below the heart and underestimated if the arm is positioned above the heart. Correct positioning of the arm is particularly important if the patient is sitting up or standing. If the arm is parallel to the patient or supported on the arm-rest, the systolic and diastolic blood pressures may be 10 mm Hg higher than if the arm is supported horizontally at heart level (level of the midsternum),60–65 and in patients with hypertension, the difference in arm position can cause an overestimation of systolic blood pressure 20 mm Hg.64 With the patient supine, the arm should be supported at the level of the phlebostatic axis (one-half the distance from the sternum to the back) rather than placed on the bed, a situation that causes an overestimation of systolic and diastolic blood pressures of 3 to 5 mm Hg.61,62,66 If a patient is in a lateral recumbent position, the noninvasive measurements of blood pressure taken from the “up arm” may be 13 to 17 mm Hg lower than measurements in supine patients, and blood pressure measurements from the “down arm” are either inconsistent or similar to measurements obtained with the patient supine.67–69Obesity alone does not affect the accuracy of blood pressure measurements.70 Blood pressure measured in the forearm can be used if a correct cuff cannot be found54,71,72; however, blood pressure in the forearm may be higher than blood pressure in the upper arm. For example, in a study73 of patients who were morbidly obese, only 19% had systolic and 28% had diastolic blood pressure measurements in the forearm within 10 mm Hg of the measurements in the upper arm.The challenge with measuring blood pressure in patients who are morbidly obese is finding an appropriately sized cuff, although new cuffs are being developed that have long length but normal width. For every 5-cm increase in arm circumference (starting at 35 cm), use of a standard cuff leads to an overestimation of systolic blood pressure by 3 to 5 mm Hg and diastolic blood pressure by 1 to 3 mm Hg compared with an appropriately sized large cuff.74 To size the cuff correctly, measure the circumference of the patient’s arm midway between the elbow and the wrist. Cuff size should be similar to that specified in the guidelines for upper arm circumference (Table 2). The cuff should be centered between the elbow and wrist, and the arm should be supported at the level of the heart.60–64No evidence-based guidelines are available for noninvasive measurement of blood pressure in patients with arrhythmias. Current recommendations based on the American Heart Association consensus54 for auscultated blood pressure in patients with arrhythmias are (1) measure the blood pressure 3 times and use the mean value, and (2) in patients with severe bradycardia, slow deflation of the cuff (target in bradycardia, 2 to 3 mm Hg per pulse) to prevent underestimation of systolic blood pressure and overestimation of diastolic blood pressure. A potential limitation of the use of oscillometric measurement of blood pressure in patients with marked arrhythmias is that with this method the maximal oscillation (mean arterial pressure) is detected and the systolic and diastolic blood pressures are estimated. In patients with atrial fibrillation or frequent ectopy, the beat-to-beat variability of stroke volume and the height of the oscillation may preclude the accurate measurement of the mean arterial pressure and thus the systolic and diastolic blood pressures. Conversely, auscultated systolic blood pressure may be overestimated or underestimated on the basis of selection of the first Korotkoff sound. In a comparison75 of 3 sets of auscultated and oscillometric measurements of blood pressure in patients with rate-controlled atrial fibrillation, the mean (standard deviation) measurements of blood pressure for each method were as follows: mm mm mm mm These findings that the methods are Because the for oscillometric blood pressure the results of a single study cannot be to If a patient is an oscillometric cuff at the results should be by The accuracy of oscillometric measurements of blood pressure in patients with atrial fibrillation has not been practice of oscillometric pressure to determine if an arterial pressure system is accurate and to to the arterial pressure or the cuff pressure is not evidence The following should be when this practice. the and measurements of blood pressure are not the As a blood pressure into the it is with an increase in systolic blood pressure and a decrease in diastolic blood the mean arterial pressure is more measurements of systolic blood pressure are lower than measurements of systolic blood pressure by 7 to mm Hg and are similar to or higher than diastolic blood pressure by 1 to mm the mean arterial pressure is the differences in systolic blood pressure change with the as systolic blood and and the as = In addition to an for or in blood pressure over time to guide clinical decisions is the more important clinical are the blood pressure is if a method accurately blood and the aspects of the method have been pressure particularly with blood to be which may lead to an overestimation of systolic pressure and an underestimation of diastolic A evidence-based for for an invasive catheter is in Table to in this are (1) an on of the and pressure during of the and (2) the use of the the system with 10 mL of through the to any The should never be performed when the catheter is in place in a patient because of the risk of air this the was of pressure with a blood had and were The addition of the the and evidence-based are also available to a system it is in use in a is performed for 3 primary detection of and of the and of the a system, a chest lead or should be used instead of lead for the of of an requires the following in lead right arm on left left arm at position, left at the for lead and for lead However, the system is not as accurate as system for the of vs The for the of cannot be to For example, in a study by and the in from that in in of cases with vs and use of in 20% compared with use of and the most for the of (Figure 2). a lead or that allows of the between the and the may also in the (Table the of for it is not for baseline the or may be a of however, this change can be by than of mm or of greater than 1 to 2 mm (Figure who have or who have may have of which are often of or without or For example, in a of 11 of in patients, had transient and of these had in of of in patients after an or were detected and of were might be if is is the lead with the maximal (Figure during an or a The usefulness of the on the of the The is useful in detecting after a However, et found that when the was of were not Of leads and did not show in of may be detected in multiple leads for a If is not the leads that are most and specific for detecting should be (Table of the recommendations for are based on expert The which represents the of and is measured from the of the to the the to the baseline (Figure to in identifying this is to a the of the of the the end of the is this the If a is the is measured from the of the to the between the and the (Figure however, if the is large and with the it should be included in the may the best between the and the If a is the of the return of the to baseline should be has been on how to measure the during atrial is to take the from the and and the 2 The lead should be used for the is related to heart it must be or to a heart of The most commonly used to the is the which is the by the of the in is about the use of the because it results in an underestimation of the at heart and of it at high heart normal is than in and than in for is greater than and for is greater than A
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