Starting the Research Process

Nursing Research January/February 2010 Vol 59, No 1, 18–25 Effectiveness of an Aspiration Risk-Reduction Protocol Norma A. Metheny 4Jami Davis-Jackson 4Barbara J. Stewart b Background: Aspiration of gastric contents is a serious prob- lem in critically ill, mechanically ventilated patients receiving tube feedings. b Objectives: The purpose of this study was to evaluate the effectiveness of a three-pronged intervention to reduce as- piration risk in a group of critically ill, mechanically ventilated patients receiving tube feedings. b Methods: A two-group quasi-experimental design was used to compare outcomes of a usual care group (December 2002 YSeptember 2004) with those of an Aspiration Risk- Reduction Protocol (ARRP) group (January 2007 YApril 2008). The incidence of aspiration and pneumonia was compared between the usual care group ( n= 329) and the ARRP group ( n= 145). The ARRP had three components: maintaining head-of-bed elevation at 30 -or higher, unless contraindicated; inserting feeding tubes into distal small bowel, when indicated; and using an algorithmic approach for high gastric residual volumes. b Results: Two of the three ARRP components were imple- mented successfully. Almost 90% of the ARRP group had mean head-of-bed elevations of 30 -or higher as compared to 38% in the usual care group. Almost three fourths of the ARRP group had feeding tubes placed in the small bowel as com- pared with less than 50% in the usual care group. Only three patients met the criteria for the high gastric residual volume algorithm. Aspiration was much lower in the ARRP group than that in the usual care group (39% vs. 88%, respectively).

Similarly, pneumonia was much lower in the ARRP group than that in the usual care group (19% vs. 48%, respectively). b Discussion: Findings from this study suggest that a combi- nation of a head-of-bed position elevated to at least 30 -and use of a small-bowel feeding site can reduce the incidence of aspiration and aspiration-related pneumonia dramatically in critically ill, tube-fed patients. b Key Words: enteral nutrition &preventive measures &respiratory aspiration F requent aspiration of gastric contents predisposes tube- fed patients to pneumonia, especially those who are critically ill and mechanically ventilated. Airway protection from regurgitated gastric contents often is impaired in these patients by underlying illness, sedation, or both. A number of interventions have been proposed to minimize aspiration. For example, a research-based guideline issued by the Centers for Disease Control and Prevention recommends a head-of-bed position elevated to at least 30 -to reduce risk for aspiration- related pneumonia (Tablan et al., 2004). Further, a fre- quently cited study of aspiration in mechanically ventilated patients found that aspiration was significantly more likely when patients were supine; however, it also occurred when they were semirecumbent (Torres et al., 1992). Findings from the Torres et al. (1992) study are convincing in that the methods used to detect aspirati on were scientifically sound (radiolabeled enteral formula and comparisons between organisms found in the subjects’ stomachs and lungs). Other investigators have found that r isk for pneumonia is increased by a low backrest elevated position (Grap et al., 2005). In- vestigators have shown that written medical orders for head-of- bed elevation are helpful in encouraging staff to maintain the appropriate backrest elevation (Helman, Sherner, Fitzpatrick, Callender, & Shorr, 2003). There is widespread agreement that an elevated head-of-bed position is helpful in reducing aspiration and pneumonia (Grap et al., 2005; Tablan et al., 2004; Torres et al., 1992). A distal small-bowel feeding site has also been recom- mended to reduce aspiration risk, although it is less well sub- stantiated by research; presumably a small-bowel feeding site reduces the likelihood of gastroesophageal reflux (Heyland, Drover, Dhaliwal, & Greenwood, 2002). Studies of the re- lationship between small-bowel feedings and aspiration have produced conflicting results. For example, in a study of 33 critically ill patients, Heylan d, Drover, MacDonald, Novak, and Lam (2001) used radiolabe led formula to assess the extent of aspiration when feed ing tubes were situated in var- ious segments of the gastroint estinal tract. The rate of as- piration was 5.8% in the stomach ( n=21),4.1%inthefirst portion of the duodenum ( n= 8), 1.8% in the second portion of the duodenum ( n= 3), and 0% in the fourth portion of the duodenum ( n= 1). Overall, patients fed in the stomach tended to have more microaspiration than patients fed beyond the pylorus (7.5% vs. 3.9%, p= .22). When the 18 Nursing Research January/February 2010 Vol 59, No 1 Norma A. Metheny, PhD, RN, is Professor, School of Nursing, Saint Louis University, Missouri.

Jami Davis-Jackson, MSN, RN, ACNP-BC, is Nurse Practitioner, Department of Heart Services, Barnes-Jewish Hospital, St. Louis,Missouri.

Barbara J. Stewart, PhD, is Professor Emeritus, Oregon Health and Science University, Portland. Copyright @ 20 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 10 logarithmic mean of the radioactivity count was compared across groups, there was also a trend toward increased microaspiration (1.9 vs. 1.4 counts/g, p= .09) in patients fed into the stomach (Heyland et al., 2001). However, also using radiolabeled enteral formula, other investigators found no significant difference in aspiration in 27 patients fed in the stomach and 24 fed transpylorically (7% vs. 13%, respec- tively; Esparza, Boivin, Hartshorne, & Levy, 2001). Al- though Heyland et al. (2001) and Esparza et al. used a reliable test for aspiration, both studies had relatively small sample sizes. Another problem with the Esparza et al. study was failure to provide information about the degree of as- piration encountered in patients fed in different portions of the small bowel. Despite the conflic ting research findings regard- ing feeding tube location, many physicians prefer small-bowel feedings in patients at high risk for aspiration, provided the procedure can be performed at the bedside by bedside nurses (Heyland, Cook, & Dodek, 2002). There is evidence that bed- side nurses can be taught how to successfully place feeding tubes into the distal small bowel (Welch, 1996). Finally, an algorithmic approach to deal with high gastric residual volumes (GRVs) has been proposed (Bourgault, Ipe, Weaver, Swartz, & O’dea, 2007; Kattelmann et al., 2006).

For example, it has been recommended that gastric feedings be interrupted when a residual volume of 500 ml or more is identified (McClave et al., 2002), and it has been suggested that prokinetic drugs be initiated when GRVs of 250 ml or greater are identified (Booth, Heyland, & Paterson, 2002; Nguyen et al., 2007). A drawback to the use of prokinetics is their potential to produce undesirable side effects, such as dystonic reactions (Dubow, Leikin, & Rezak, 2006; Kenney, Hunter, Davidson, & Jankovic, 2008; Pasricha, Pehlivanov, Sugumar, & Jankovic, 2006; van der Padt, van Schalk, & Sonneveld, 2006). Although the effects of single risk factors for aspiration have been studied previously, no studies were identified in which the combined effects of postpyloric tube site, head-of- bed elevation, and GRV were evaluated. Because it is likely that a combination of aspiration-risk-reducing interventions will be more beneficial than a single intervention, the study reported here was used to evaluate the effectiveness of a three- prongedinterventiontoreduceaspirationriskinagroupof critically ill, mechanically ventilated tube-fed patients.

Methods Design A two-group quasi-experimental design was used to compare outcomes of a usual care group with those of an Aspiration Risk-Reduction Protocol (ARRP) group. Both groups in- cluded critically ill, mechanically ventilated tube-fed patients cared for in the same intensive care units (ICUs). The primary outcomes of interest were the frequency of aspiration and the incidence of pneumonia. A secondary outcome was the use of hospital resources (length of hospitalization, length of inten- sive care stay, and number of days of mechanical ventilation).

The study was approved by the appropriate institutional review boards. A secondary data analysis was performed on the usual care group. Patients in the usual care group who had surgically or endoscopically placed tubes were eliminated from the analysis for the work reported here. Setting Both phases of the study took place in the same five ICUs at a Level 1 trauma center in the Midwest. Major services pro- vided in the ICUs included neuromedicine/neurosurgery, trauma/surgery, and general medicine/pulmonary medicine.

Subjects The usual care group ( n= 329) was studied prospectively between December 2002 and Sep tember 2004 (Metheny et al., 2006). The ARRP group ( n= 145) was studied prospectively between January 2007 and April 2008. Inclusion criteria for the ARRP group were the same as for the usual care group:

(a) admitted to one of the five ICUs at the study site, (b) age Q18 years, (c) informed consent of patient or legal guardian, (d) mechanical ventilation, and (e) medical order for blind insertion of feeding tube at bedside. Exclusion criteria were as follows: (a) pneumonia present before tube feeding started, and (b) medical order for surgically or endoscopi- cally placed feeding tube. All patients who met the criteria were invited to par- ticipate for a 3-day period. Although the ARRP was im- plemented for all tube-fed patients in the ICUs, data were collected only on those who gave informed consent. Regis- tered nurse research assistants were present 16 hours a day, 7 days a week, to recruit patients, to obtain informed con- sents, and to collect data. The same measurements were made on the usual care group and ARRP group.

Independent Variable The independent variable consisted of the two treatment conditions (usual care and the ARRP). Usual care was defined as the absence of a systematic approach to minimize risk for aspiration. In 2002 Y2004, standing medical orders on the ICUs did not routinely in- clude information about head-of-bed elevation, and nurses did not chart head-of-bed angles on the patients’ flow sheets. Further, no formal program was in place to teach ICU nurses how to place small-bowel feeding tubes. Fi- nally, there was no standardized approach for dealing with high GRVs. The ARRP had three components: (a) maintain head-of- bed elevation at 30 -or higher, unless medically contra- indicated; (b) insert feeding tube into distal small bowel, when requested by the attending physician; and (c) initiate an algorithmic approach for high GRVs. Before initiation of the study in 2007, the hospital nurs- ing practice committee and the ICU medical directors ap- proved the ARRP for use in the ICUs, and 2 months before data collection, an advanced practice nurse skilled in critical care and nasoenteral tube placement initiated an educational program to introduce the protocol to the ICU staff. This nurse was present 40 hours a week during the ARRP phase of the study to encourage adoption of the protocol in the ICUs involved. Coaching by the advanced practice nurse con- sisted of a combination of teaching, training, and counsel- ing designed to promote diffusion of the ARRP components.

The advanced practice nurse also provided monthly feedback about implementation of the interventions and reinforced desired behaviors by emphasizing successful aspects of the protocol delivery. Nursing Research January/February 2010 Vol 59, No 1 Reducing Risk for Aspiration in Tube-Fed Patients 19 Copyright @ 20 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 10 Maintain Head-of-Bed Elevation at 30 oor Higher, Unless Med- ically Contraindicated Attending physicians were encour- aged to write orders for the desired head-of-bed elevation, and this action promoted appropriate patient positioning.

Also, bedside nurses were encouraged to record head-of-bed angles at hourly intervals on t he patients’ ICU flow sheets; this action reminded the nurses to check the bed position frequently and make corrections as necessary.

Insert Feeding Tube Into Distal Small Bowel, When Requested by Attending Physician Physicians were informed that the advanced practice nurse would assist ICU nurses with small- bowel tube insertions at the bedside. Thus, physicians were able to write orders more freely for bedside small-bowel tube insertions when they were deemed important for high- risk patients. The advanced practice nurse demonstrated small-bowel tube insertion to bedside nurses who were un- skilled in this procedure and coached these nurses during small-bowel tube insertions until they gained proficiency in the procedure. A videotape of a successful tube insertion was made available in all of the ICUs for nurses to view at their discretion to facilitate learning further. The tube insertion procedure consisted of several steps. First, the patient’s attending p hysician was contacted to ob- tain permission to administer metoclopramide, 10 mg, in- travenously. If permission was o btained, the medication was administered 10 minutes before introduction of the feeding tube through the patient’s mouth or right or left naris (whichever was most appropriate ). Metoclopramide increases gastric and small intestinal moti lity and thus facilitates place- ment of a feeding tube into the small bowel (Rohm, Boldt, & Piper, 2009). The feeding tube was advanced to the 55- to 60-cm mark, and an attempt was made to aspirate gastric contents. If an aspirate was obtained, its pH was measured with a pH test strip and the ap pearance of the aspirate was observed. If the pH was 6 or higher and the aspirate had the appearance of sputum, the tu be was removed and a second attempt was made to insert the tube via the esophagus into the stomach. A pH less than 6 and an aspirate with a gastric appearance were used as an indi cation of tube placement in the stomach. The feeding tube was advanced gently with a rotating motion. When the 90- to 100-cm mark was reached, another attempt to aspirate fluid was made. This attempt was facilitated by injecting 30 ml of air through the tube to force the tube’s ports away from the intestinal mucosa. An aspirate pH Q6withbilestainingwasusedasanindication of tube placement past the pylorus. A confirmatory radio- graph was obtained to determine actual tube location.

Detect and Manage High GRVs The algorithmic approach used to manage high GRVs during gastric feedings is de- picted in Figure 1.

Measurements Measurements performed on the usual care and ARRP groups are summarized in Table 1 and described later. All of the registered nurse data collectors were trained by the principal investigator and the project director on scoring of the measurements before data collection.

Pepsin Assay to Detect Aspiration of Gastric Contents Bedside nurses collected tracheal secr etions in sputum traps during routine suctioning (between 0800 and 2400 hours) on Days 1, 2, and 3. The specimens were treated and frozen at j20 -C in a hospital laboratory before being transported to a research laboratory for pepsin analysis. The immunoassay used for pepsin analysis has been described previously (Metheny et al., 2006). In an animal model study, the assay was shown to have a sensitivity of 92.5% and a specificity of 100% (Metheny et al., 2004). The same biochemist, blinded to patients’ clinical status, in terpreted all of the assays and recorded the results as either po sitive or negative. A positive reading indicated that the specimen contained pepsin in a concentration Q1Hg/ml. The percentage of pepsin-positive tracheal secretions was calculated for each patient. The mean number of tracheal secretions assayed per patient was 15.9 (SD = 4.7) in the usual care group and 13.1 ( SD =4.2)inthe ARRP group.

Clinical Pulmonary Infection Score The Clinical Pulmonary Infection Score (CPIS) descri bed in Table 2 was used to assess for pneumonia at the end of Days 1, 2, 3, and 4 (Luna et al., 2006). Data on infiltrates were obtained from radiographic reports. The first blood gas of the day was used to calculate the oxygenation PaO 2/FiO 2ratio. Bedside nurses estimated the volume and appearance of tracheal secretions at the time of routine suctioning. Blood leukocyte data were obtained from laboratory reports, and temperature data were obtained from the medical records. When an infiltrate was present, a FIGURE 1. Algorithm outlining actions for high gastric residual volumes observed during gastric feedings. 20 Reducing Risk for Aspiration in Tube-Fed Patients Nursing Research January/February 2010 Vol 59, No 1 Copyright @ 20 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 10 CPIS score Q6 was used as a proxy for pneumonia. The same individual, blinded to the pepsin assay results, calculated all of the CPIS scores. In an earlier study, investigators found sig- nificant agreement ( r= .96) between the simplified CPIS results and 34 bronchoalveolar lavages ( pG.001; Metheny et al., 2006). Another group of investigators compared postmortem examinations of 38 patients who had died after at least 72 hours of mechanical ventilat ion and compared their CPIS scores with bronchoscopic and histological techniques; accord- ing to their findings, the CPIS had a sensitivity of 72% and a specificity of 85% for pneumonia (Papazian et al., 1995).

Use of Hospital Resources Information needed to calculate hospital length of stay, ICU length of stay, and ventilator days was obtained through chart review.

Head-of-Bed Angle During both phases of the study, regis- tered nurse data collectors determined hourly backrest angles from digital readouts available o n the patients’ beds (Stryker Medical, Kalamazoo, MI). During the ARRP phase of the study, the bedside nurses were encouraged to use the beds’ digital readouts to determine hourly backrest elevations and to record their findings on the patients’ flow sheets. The same beds were in use during both phases of the study. In a previous study, investigators compare d 1,002 readings made between digital readouts on the Stryke r Apex or Stryker EPIC II Criti- cal Care beds and those obtained from a handheld angle reader; the Pearson correlation was .87, pG.001. However, the mean bed readouts tended to be higher than the mean readings obtained from the handheld device (21.3 T13.3 vs. 18.9 T11.7; Metheny et al., 2006). Feeding Tube Site Radiographic confirmation of tube lo- cation was obtained immediately after tube insertion; also at this time, the length of tubing extending from the exit site was measured with a centimeter tape. This measure was repeated at 4-hour intervals between 0800 and 2400 on Days 1,2,and3;alsoassessedatthesetimeswerethepHandthe appearance of fluid aspirated from the feeding tubes. The efficacy of these measures in detecting tube dislocation has been described previously (Metheny et al., 2005). When there was concern about possible tube dislocation, the need for a radiograph was discussed with the patient’s at- tending physician. In addition, reports of radiographic stud- ies performed on Days 1, 2, and 3 were reviewed to observe for radiographic evidence of tube movement. About half of the patients had at least one treatment-related X-ray during the study period that included information about the feeding tube’s location.

Residual Volumes From Feeding Tubes Research nurses used 60-ml syringes to measure volumes from feeding tubes every 4 hours. Approximately 30 ml of air was injected into the q TABLE 1. Patient Measurements, Scoring, and Frequency Measurements Scoring Frequency Aspiration of gastric contents (pepsin immunoassay performed on tracheal secretions) 1 = present, 0 = absent Each time patient is suctioned Pneumonia (simplified CPIS) Range 0 Y10 Every 24 hours Q6 positive for pneumonia Days 1, 2, 3, 4 Use of hospital resources Hospital length of stay Time of discharge or death ICU length of stay Days Ventilator use Head-of-bed angle 0 -Y90- Every hour Feeding site Stomach First portion of duodenum Second and third portion duodenum Fourth portion of duodenum Proximal jejunum Time of initial X-ray and every 4 hours thereafter Level of consciousness (GCS) Range 3 Y15 Every 4 hours Level of sedation (Vancouver Interaction and Calmness Score) Range 10 Y60 Every 4 hours GRV Number Q250 ml Every 4 hours APACHE II score 0 Y71 At time of admission to ICU Note. CPIS = Clinical Pulmonary Infection Score; ICU = intensive care unit; GCS = Glasgow Coma Scale; GRV = gastric residual volume;APACHE II = Acute Physiology and Chronic Health Evaluation II. q TABLE 2. Simplified CPIS Component Value Points Temperature ( -C) Q36.5 and e38.4 0 Q38.5 and e38.9 1 Q39.9 and e36.0 2 Blood leukocytes per mm 3 Q4,000 and e11,000 0 G4,000 or 911,000 1 Tracheal secretions Few 0 Moderate 1 Large 2 Purulent +1 Oxygenation (PaO 2/FiO 2mm Hg) 9240 or presence of ARDS 0 e240 and absence of ARDS 2 Chest radiograph No infiltrate 0 Patchy or diffuse infiltrate 1 Localized infiltrate 2 Note. CPIS = Clinical Pulmonary Infection Score; ARDS = acute respiratory distress syndrome. Nursing Research January/February 2010 Vol 59, No 1 Reducing Risk for Aspiration in Tube-Fed Patients 21 Copyright @ 20 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 10 feeding tube before each attempt to withdraw fluid from the tube, then slow and steady negative pressure was applied with the plunger. The procedure was repeated until no more fluid could be withdrawn. The total volume of fluid removed from the feeding tube was reported in milliliters. Policy at the data collection site called for returning a GRV of 200 ml or less to the patient and discarding of any amount greater than 200 ml.

Level of Consciousness The Glasgow Coma Scale (GCS), adjusted for use with intubated patients, was used by the research nurses to assess patients’ level of consciousness at 4-hour intervals from 0800 through 2400 hours. Scoring of the GCS is based on three components (best eye response, best motor response, and best verbal response). The worst possible total score is 3, and the best possible total score is 15. Because all of the patients were intubated tracheally, the verbal response was scored as generally unresponsive, ability to converse is in question, or appears able to converse. In a prospective, ob- servational study, two observers determined the GCS of 39 poisoned patients; the weighted kappa score for the total GCS was .85, and the weighted kappa scores for individual com- ponents of the GCS ranged between .63 and .78 (Heard & Bebarta, 2004). In a review of published studies in which GCS was used, the tool was found to have good reliability (intraclass correlation coefficient, .8 to 1.0 for trained users); further, it was found to have well-established cross-sectional construct validity (Prasad, 1996).

Level of Sedation The Vancouver Interaction and Calmness Scale was used to assess patients ’ level of sedation (de Lemos, Tweeddale, & Chittock, 2000). This scale was developed for use with adult, critically ill, mechanically ventilated patients, and it consists of two 5-item subscales quantifying inter- action along a continuum from 5 to 30 points; the scores may range from 10 to 60. A low score indicates a high level of sedation. The tool’s developers report interrater reliability forthetwoscalesas.89and.90andinternalconsistencyas .95 for both subscales (de Lemos et al., 2000).

Severity of Disease The Acute Physiology and Chronic Health Evaluation II (APACHE II) score was calculated at the time of the patient’s admission to the ICU. This tool is designed to measure the severity of disease for adult patients admitted to ICUs. The tool has three components: acute physiology score, age, and chronic health. Overall, an integer score from 0 to 71 is computed on the basis of temperature, mean arterial pressure, heart rate, respiration rate, oxygen- ation, serum sodium, serum potassium, serum creatinine, hematocrit, white blood count, GCS score, age, and chronic health points (Knaus, Draper, Wagner, Zimmerman, 1985).

Higher scores imply more severe disease state and greater risk for death. The acute physiology score component of the APACHE II instrument is highly reproducible (intraclass correlation coefficient = .90), and the age component of the instrument has an even higher reproducibility (intraclass correlation coefficient = .998). The chronic health compo- nent of the instrument does not fare as well (kappa = .66; Damiano, Bergner, Draper, Knaus, & Wagner, 1992).

Other Observations Demographic information was obtained by chart review. The number of vomiting episodes was de- termined by interviewing bedside nurses and by chart review. Data Analysis Simple descriptive statistics were used to describe the sam- ple. To determine the effect of the ARRP on frequency of aspiration, we used a ttest for independent groups to com- pare patients in the usual care and ARRP groups on the mean percentage of pepsin-positive tracheal secretions. To deter- mine the effect of the ARRP on the incidence of pneumonia, we used a ztest for comparing proportions in independent groups to compare the proportion of usual care patients with the proportion of ARRP patients with a positive CPIS for q TABLE 3. Description of Usual Care and ARRP Groups Variable Usual care (n= 329) ARRP group (n= 145) Age (years) 52.5 T18.1 48.8 T17.8* Gender Female 42.9% 35.2% Male 57.1% 64.8% APACHE II 22.7 T6.4 19.5 T5.7** Service Neuromedicine/neurosurgery 30.4% 33.2% Trauma/surgery 39.8% 44.8% General medicine/pulmonary medicine 29.8% 22.1% Level of consciousness (mean GCS score) 7.0 T2.8 6.9 T2.2 Level of sedation (mean Vancouver Interaction and Calmness Score) 35.7 T4.1 36.5 T4.1* Feeding site Stomach throughout study 47.7% 27.6%** Small bowel throughout study 40.7% 69.7% Switch from stomach to small bowel 4.0% 0.0% Switch from small bowel to stomach 7.6% 2.8% Type of device during gastric feedings 10-Fr polyurethane tube 47.1% 75.0%** 14- to 18-Fr polyvinyl chloride tube 52.9% 25.0% Type of device during small-bowel feedings 10-Fr polyurethane tube 100% 100% One or more GRVs Q250 ml in gastric-fed patients 15.9% 7.5% Vomited at least once 5.8% 5.5% Mean backrest elevation ( -) 23.7 T12.4 37.8 T9.1** Mean percent backrest elevation Q30- 37.7% 88.4%** Died during hospitalization 19% 14% Note. ARRP = Aspiration Risk-Reduction Protocol Group; APACHE II = Acute Physiology and Chronic Health Evaluation II.*pe.05. **pe.001. 22 Reducing Risk for Aspiration in Tube-Fed Patients Nursing Research January/February 2010 Vol 59, No 1 Copyright @ 20 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 10 pneumonia on Day 4. Significant baseline differences be- tween the two groups were controlled for in the analyses. To evaluate the effect of the ARRP on hospital resources, we compared usual care and ARRP groups using a ztest from the Mann YWhitney U test because the secondary outcomes of hospital length of stay, ICU length of stay, and days of ventilator use had skewed distributions.

Results Descriptive Data Descriptive data on both groups are provided in Table 3. As shown in Table 3, the ARRP and the usual care groups did not differ in gender, level of consciousness, and service that provided care. However, the ARRP group was younger, had a lower mean APACHE II score, and was less sedated than the usual care group. The mean head-of-bed elevation was significantly higher in the ARRP group than that in the usual care group (37.8 -T 9.1 -vs. 23.7 -T 12.4 -, respectively, pG.001). Fur- ther, a mean head-of-bed elevation Q30 -was achieved in 88% of the ARRP group as opposed to 38% of the usual care group ( pG.001; Figure 2). Physicians included orders for the desired head-of-bed angle in 90% ( n=130)ofthe 145 ARRP patients. Bedside nurses charted the head-of-bed angle in 44% of the possible observations. As shown in Figure 3, a small-bowel feeding site was achieved in 72.4% of the ARRP group compared with 48.3% of the usual care group ( pG .001). Further, tube placement past the proximal duodenum was achieved in 53.1% of the ARRP group com pared with 18.2% of the usual care group ( pG.001). Three patients in the ARRP group met the criteria for im- plementation of the high GRV algorithm depicted in Figure 1.

One patient had nine high GRVs (ranging between 300 and 700 ml), a second had two high GRVs (both 350 ml), and a third had one GRV of 325 ml. However, physicians chose not to implement the algorithm in any of the cases.

Effect of the ARRP on Aspiration, Pneumonia, and Use of Hospital Resources Aspiration was significantly lower in patients in the ARRP group than that in usual care group, as evidenced by a lower mean percentage of pepsin-positive tracheal secretions (12.4% T21.8% vs. 30.9% T24.2%, pG.001). Aspirating at least once was half as likely in the ARRP group as in the usual care group (39.3% vs. 88.4%, pG.001). Further, pneumonia occurred in less than one fifth of the ARRP group but in nearly half of the usual care group (19.3% vs.

48.2%, p G .001; Figure 4). The ARRP patients were hospitalized on average 2.2 fewer days than usual care pa- tients (25.1 T14.9 vs. 27.3 T13.4, zfrom Mann YWhitney U test = j2.39, p= .017), and the average ICU length of stay for ARRP patients was 1.9 fewer days than for usual care patients (21.3 T10.5 vs. 19.4 T12.1, zfrom Mann Y Whitney U test = j2.46, p= .014). Finally, ARRP patients averaged 1.5 fewer days of mechanical ventilation than the usual care patients (16.2 T9.7 vs. 17.7 T9.8, respectively, zfrom Mann YWhitney U test = j1.46, p= .14; Figure 5). When the usual care and the ARRP groups were compared on the outcome variables using age, APACHE II, and sedation as covariates, the results were nearly identical.

Discussion Success in Delivery of the ARRP Two of the three components of the ARRP were imple- mented successfully. That is, almost 90% of the ARRP group FIGURE 2. Comparison of percentages of mean head-of-bed elevations equal to or greater than 30 -in the usual care and ARRP groups. FIGURE 3. Comparison of feeding tube sites in the usual care and ARRP groups.

FIGURE 4. Comparison of aspiration and pneumonia (present or absent) in the usual care and ARRP groups. Nursing Research January/February 2010 Vol 59, No 1 Reducing Risk for Aspiration in Tube-Fed Patients 23 Copyright @ 20 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 10 had mean head-of-bed elevations of 30 -or higher and almost three fourths had feeding tubes placed in the small bowel (most beyond the proximal duodenum). Successful implementation of a head-of-bed elevated po- sition probably was influenced by a number of factors. Writ- ten medical orders regarding the desired backrest angle eliminated the possibility of elevating the backrest inap- propriately and reminded staff of the importance of proper positioning. Frequent documentation of the backrest angle ensured corrections as needed. Also, the documentation probably enhanced the nurses’ sense of responsibility for appropriate patient positioning. A factor that also may have had a significant effect on the greater use of an elevated head-of-bed position in the ARRP group, as compared with the usual care group, was the growing number of publications emphasizing the need for an elevated head-of- bed position to prevent pneumonia (Grap et al., 2005; Tablan et al., 2004). Successful implementation of small-bowel feeding tube insertions also probably was influenced by several factors.

Many physicians prefer small-bowel feedings in patients at high risk for aspiration, provided the procedure can be performed at the bedside by bedside nurses, and in this study, the educational program provided by the advanced practice nurse allowed a cadre of bedside nurses in the five ICUs to significantly improve their success in placing small- bowel feeding tubes. Poor use of the algorithm was due to reluctance of the attending physicians to prescribe prokinetic agents for the three patients who met the criteria in the algorithm depicted in Figure 1. In all three cases, the physicians expressed con- cern about recent published reports of possible undesirable effects associated with prokinetic agents (Dubow et al., 2006; Kenney et al., 2008; Pasricha et al., 2006; van der Padt et al., 2006).

Improvement in Outcomes To determine if younger age, better APACHE II score, and lower level of sedation had a significant effect on outcomes (aspiration and pneumonia), we entered these factors as covariates in the analyses. These factors had no significant effect on outcomes when the two groups were compared. The combination of an elevated head-of-bed position and a mid-to-distal small-bowel feeding site probably contributed to the significantly less aspiration and pneumonia in the ARRP group than that in the usual care group. The shorter hospital and ICU lengths of stay in the ARRP group were modest and doubtless influenced by the lower incidence of pneumonia.

Head-of-Bed Elevation The supine position is a well-recognized risk factor for aspiration. As indicated earlier, there is a wide- spread agreement that an elevat ed head-of-bed position is helpful in reducing aspiration and pneumonia (Grap et al., 2005; Tablan et al., 2004; Torres et al., 1992).

Small-Bowel Feeding Site Findings from the study reported here support those of other investigators who used a sensitive and specific test for aspiration of gastric contents (Heyland et al., 2001).

Gastric Residual Volume Because the algorithm for high GRVs during gastric feedings was not implemented in the three ARRP patients with one or more GRVs Q250 ml, it was not possible to determine what effect it might have had on their rates of aspiration (which ranged between 50% and 100%). The study reported here adds to the evidence that an ele- vated head-of-bed position is helpful in preventing aspiration and pneumonia; further, it adds to the evidence that a distal small-bowel feeding site is associated with less aspiration than is the gastric feeding site. It is regrettable that the GRV component of the protocol could not be implemented and evaluated.

Strengths of the Study The highly sensitive and specific pepsin assay allowed an accurate comparison of the two groups on aspiration, and the large sample size provided adequate power to compare the usual care and ARRP groups on the major outcome variables (aspiration and pneumonia). The presence of skilled regis- tered nurse research assistants for 16 hours a day, 7 days a week throughout both phases of the study allowed for uniformity in data collection procedures.

Limitations A limitation of the study was the 28-month time lapse be- tween the end of the usual care phase of the study and the beginning of the ARRP phase. It is conceivable that changes that occurred in the clinical site during that period could have accounted for some of the differences in out- comes. Another limitation was our sole reliance on the Clinical Pulmonary Infection Score to estimate the incidence of pneumonia.

Conclusions Findings from this study suggest that a combination of a head-of-bed position elevated to at least 30 -and the use of a small-bowel feeding site (especially beyond the first por- tionof the duodenum) can reduce the incidence of aspiration and aspiration-related pneumonia dramatically in critically ill, mechanically ventilated patients. It is highly probable that the presence of a skilled critical care nurse with special training in the placement of small-bowel feeding tubes played a signifi- cant role in encouraging ICU personnel at the study site to adopt the aspiration-reducing interventions and bring about the desired outcomes shown in this study. q FIGURE 5. Comparison of use of hospital resources by the usual care and ARRP groups.

24 Reducing Risk for Aspiration in Tube-Fed Patients Nursing Research January/February 2010 Vol 59, No 1 Copyright @ 20 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 10 Accepted for publication August 17, 2009.

This study was funded by the National Institute of Nursing Research,grant no. R01NR05007.

Corresponding author: Norma A. Metheny, PhD, RN, School ofNursing, Saint Louis University, 3525 Caroline Mall, St. Louis, MO63104 (e-mail: [email protected]).

ReferencesBooth, C. M., Heyland, D. K., & Paterson, W. G. (2002). Gastro-intestinal promotility drugs in the critical care setting: A systematicreview of the evidence. Critical Care Medicine, 30 (7), 1429 Y1435. Bourgault, A. M., Ipe, L., Weaver, J., Swartz, S., & O’dea, P. J.(2007). Development of evidence-based guidelines and criticalcare nurses’ knowledge of enteral feeding. Critical Care Nurse, 27(4), 17 Y22, 25 Y29. Damiano, A. M., Bergner, M., Draper, E. A., Knaus, W. A., &Wagner, D. P. (1992). Reliability of a measure of severity of illness:Acute physiology of chronic health evaluation VII. Journal of Clinical Epidemiology, 45 (2), 93 Y101. de Lemos, J., Tweeddale, M., & Chittock, D. (2000). Measuringquality of sedation in adult mechanically ventilated critically illpatients. The Vancouver Interaction and Calmness Scale. SedationFocus Group. Journal of Clinical Epidemiology, 53 (9), 908 Y919. Dubow, J. S., Leikin, J., & Rezak, M. (2006). Acute chorea associatedwith metoclopramide use. American Journal of Therapeutics , 13(6), 543 Y544. Esparza, J., Boivin, M. A., Hartshorne, M. F., & Levy, H. (2001).Equal aspiration rates in gastrically and transpylorically fedcritically ill patients. Intensive Care Medicine, 27 (4), 660 Y664. Grap, M. J., Munro, C. L., Hummel, R. S. 3rd, Elswick, R. K. Jr.,McKinney, J. L., & Sessler, C. N. (2005). Effect of backrestelevation on the development of ventilator-associated pneumo-nia. American Journal of Critical Care, 14 (4), 325 Y332. Heard, K., & Bebarta, V. S. (2004). Reliability of the GlasgowComa Scale for the emergency department evaluation of poi-soned patients. Human & Experimental Toxicology ,23(4), 197 Y200. Helman, D. L. Jr., Sherner, J. H. 3rd, Fitzpatrick, T. M., Callender,M. E., & Shorr, A. F. (2003). Effect of standardized orders andprovider education on head-of-bed positioning in mechanicallyventilated patients. Critical Care Medicine, 31 (9), 2285 Y2290. Heyland, D. K., Cook, D. J., & Dodek, P. M. (2002). Prevention ofventilator-associated pneumonia: Current practice in Canadianintensive care units. Journal of Critical Care ,17(3), 161 Y167. Heyland, D. K., Drover, J. W., Dhaliwal, R., & Greenwood, J.(2002). Optimizing the benefits and minimizing the risks of enteralnutrition in the critically ill: Role of small bowel feeding. Journal of Parenteral and Enteral Nutrition, 26 (Suppl. 6), S51 YS55. Heyland, D. K., Drover, J. W., MacDonald, S., Novak, F., &Lam, M. (2001). Effect of postpyloric feeding on gastroeso-phageal regurgitation and pulmonary microaspiration: Resultsof a randomized controlled trial. Critical Care Medicine, 29 (8), 1495 Y1501. Kattelmann, K. K., Hise, M., Russell, M., Charney, P., Stokes, M., &Compher, C. (2006). Preliminary evidence for a medical nutritiontherapy protocol: Enteral feedings for critically ill patients. Journal of the American Dietetic Association ,106 (8), 1226 Y1241. Kenney, C., Hunter, C., Davidson, A., & Jankovic, J. (2008).Metoclopramide, an increasingly recognized cause of tardivedyskinesia. Journal of Clinical Pharmacology ,48(3), 379 Y384. Knaus, W. A., Draper, E. A., Wagner, D. P., & Zimmerman, J. E. (1985). APACHE II: A severity of disease classification system.Critical Care Medicine, 13 (10), 818 Y829. Luna, C. M., Aruj, P., Niederman, M. S., Garzon, J., Violi, D.,Prignoni, A., et al. (2006). Appropriateness and delay to initiatetherapy in ventilator-associated pneumonia. European Respi- ratory Journal, 27 (1), 158 Y164. McClave,S.A.,DeMeo,M.T.,DeLegge,M.H.,DiSario,J.A.,Heyland, D. K., Maloney, J. P., et al. (2002). North AmericanSummit on Aspiration in the Critically Ill Patient: Consensusstatement. Journal of Parenteral and Enteral Nutrition, 26 (Suppl. 6), S80 YS85. Metheny, N. A., Clouse, R. E., Chang, Y. H., Stewart, B. J.,Oliver, D. A., & Kollef, M. H. (2006). Tracheobronchial as-piration of gastric contents in critically ill tube-fed patients:Frequency, outcomes, and risk factors. Critical Care Medicine, 34(4), 1007 Y1015. Metheny, N. A., Dahms, T. E., Chang, Y. H., Stewart, B. J., Frank,P. A., & Clouse, R. E. (2004). Detection of pepsin in trachealsecretions after forced small-volume aspirations of gastric juice.Journal of Parenteral and Enteral Nutrition, 28 (2), 79 Y84. Metheny, N. A., Schnelker, R., McGinnis, J., Zimmerman, G.,Duke, C., Merrit, B., et al. (2005). Indicators of tubesite duringfeedings. Journal of Neuroscience Nursing, 37 (6), 320 Y325. Nguyen, N. Q., Chapman, M., Fraser, R. J., Bryant, L. K., Burgstad,C., & Holloway, R. (2007). Prokinetic therapy for feed intoler-ance in critical illness: One drug or two? Critical Care Medicine, 35(11), 2561 Y2567. Papazian, L., Thomas, P., Garbe, L., Guignon, I., Thirion, X.,Charrel, J., et al. (1995). Bronchoscopic or blind sampling tech-niques for the diagnosis of ventilator-associated pneumonia.American Journal of Respiratory and Critical Care Medicine,152 (6 Pt. 1), 1982 Y1991. Pasricha, P. J., Pehlivanov, N., Sugumar, A., & Jankovic, J.(2006). Drug insight: From disturbed motility to disorderedmovement VA review of the clinical benefits and medicolegal risks of metoclopramide. Nature Clinical Practice. Gastro- enterology & Hepatology ,3(3), 138 Y148. Prasad, K. (1996). The Glasgow Coma Scale: A critical appraisalof its clinimetric properties. Journal of Clinical Epidemiology, 49(7), 755 Y763. Rohm, K. D., Boldt, J., & Piper, S. N. (2009). Motility disordersin the ICU: Recent therapeutic options and clinical practice.Current Opinion in Clinical Nutrition and Metabolic Care , 12(2), 161 Y167. Tablan, O. C., Anderson, L. J., Besser, R., Bridges, C., Hajjeh, R.,Centers for Disease Control, & the Healthcare InfectionControl Practices Advisory Committee. (2004). Guidelines forpreventing health-care-associated pneumonia, 2003: Recom-mendations of CDC and the Healthcare Infection Control Prac-tices Advisory Committee. Morbidity and Mortality Weekly Report. Recommendations and Reports ,53(RR-3), 1 Y36. Torres, A., Serra-Batlles, J., Ros, E., Piera, C., Puig de la Bellacasa,J., Cobos, A., et al. (1992). Pulmonary aspiration of gastriccontents in patients receiving mechanical ventilation: The effect ofbody position. Annals of Internal Medicine, 116 (7), 540 Y543. van der Padt, A., van Schalk, R. H., & Sonneveld, P. (2006).Acute dystonic reaction to metoclopramide in patients carryinghomozygous cytochrome P450 2D6 genetic polymorphisms.Netherlands Journal of Medicine ,64(5), 160 Y162. Welch, S. K. (1996). Certification of staff nurses to insert enteralfeeding tubes using a research-based procedure. Nutrition in Clinical Practice ,11(1), 21 Y27. Nursing Research January/February 2010 Vol 59, No 1 Reducing Risk for Aspiration in Tube-Fed Patients 25 Copyright @ 20 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 10