JSTOR

Study Design

This study is part of a larger project focusing on the prevention of hospital‐acquired infections in US hospitals.^10‐12 We combined quantitative and qualitative data to allow for a more detailed analysis of the complex phenomena that are inherent in the delivery of healthcare services.^13,14 First, in May 2005, we sent a survey to the lead infection control professionals (ICPs) at 719 US hospitals. The survey sample consisted of all Department of Veterans Affairs (VA) medical centers (n = 119), which are part of the country’s largest centralized healthcare delivery system, and a national, stratified, random sample of non‐VA general medical and surgical hospitals with 50 or more beds and an ICU (n = 600). Data were also obtained from the 2005 American Hospital Association (AHA) database and the 2003 Area Resource File.¹⁵

The survey responses were then used to implement a stratified purposeful sampling strategy,¹³ resulting in the selection of 14 hospitals for an in‐depth qualitative investigation. We first stratified by hospital size, then looked at our quantitative results to determine the typical infection control practices used by hospitals in each stratum, and selected hospitals with typical uses as well as hospitals with atypical uses of specific practices. The selection of hospitals also focused on achieving the maximum variation in the other relevant variables, such as whether the hospital was a VA or non‐VA facility. Semistructured telephone interviews were conducted with key stakeholders at all 14 hospitals, and 6 of the 14 hospitals were subsequently selected for a visit.

Institutional review board approval was obtained from the VA Ann Arbor Healthcare System as well as from each of the hospitals that were visited.

Survey Measures

At each acute care facility, respondents were asked how frequently certain infection control practices were used for adults who received mechanical ventilation. Frequency of practice was measured on a scale from 1 to 5 (in which 1 indicated “never” and 5 indicated “always”), with “regular use” defined as a rating of 4 or 5. Practices of interest included the use of semirecumbent positioning, the use of antimicrobial mouth rinse, aspiration of subglottic secretions by using specialized endotracheal tubes, and the use of specialized kinetic beds that oscillate. These practices were selected because there is supporting evidence for each in the literature, and they are all discussed in the Centers for Disease Control and Prevention (CDC) guidelines for preventing healthcare‐associated pneumonia.³

We also asked respondents whether the facility had a hospital epidemiologist, whether the lead ICP was certified in infection control and epidemiology, and whether the facility was participating in a collaborative effort to encourage use of infection control practices. Academic affiliation was defined as having residency training approval by the Accreditation Council for Graduate Medical Education as specified in the AHA database. The AHA database was also used to derive a measure of nurse staffing (full‐time equivalent nurses per adjusted average daily census), which has been shown to be related to patient outcomes and safety.^16‐18

Qualitative Data Collection

A total of 38 semistructured telephone interviews were conducted at 14 hosptals. The interviews were audio recorded and transcribed. Multiple interviews were conducted at each hospital (2–4 interviews ranging from 29 to 92 minutes) to get the perspectives of staff in different positions. The telephone interviews were conducted during the period from July 2005 to May 2006. The first point of contact was the lead ICP. Thereafter, we used a snowball technique whereby interviewees were asked to recommend other potential interviewees, particularly individuals who were involved in decisions related to the use of at least 1 of the infection control practices of interest. Interviewees were asked to identify which practices their organization used to prevent VAP and to discuss the decision‐making process that led their organization to use those practices (see Appendix). Interviewees were also asked about practices that were not used and why.

During the period from October 2006 to October 2007, there were 48 additional interviews conducted during visits to 6 hospitals. The hospital visits provided an opportunity to gather more in‐depth information and to confirm or explore issues mentioned during the telephone interviews. Interviewees from a wide variety of staff positions were purposefully selected because they provided different perspectives (eg, senior executives) or because they were directly involved in infection control (eg, hospital epidemiologists).

Statistical Analysis

Given our stratified sampling approach, survey data were analyzed by using sample weights based on the probability of selection in each stratum, which resulted in estimates that represented the full population of VA hospitals and non‐VA acute care hospitals with 50 or more hospital beds and an ICU. Results were reported either as weighted proportions or as weighted mean values, with 95% confidence intervals (CIs). We used weighted logistic regression to determine which hospital characteristics (as described above) were associated with the use of each infection prevention practice, while simultaneously adjusting for other factors such as the facility’s number of ICU beds. Logistic regression results were presented as odds ratios (ORs) with 95% CIs. All reported P values are 2 tailed, and all analyses were conducted using Stata, version 9.0 (StataCorp).

The qualitative analysis was conducted using rigorous qualitative procedures.^13,19 First, we established a preliminary codebook that was based on our study’s conceptual model. This codebook was revised by having 4 members of the research team independently code 2 transcripts and then meet to discuss the codes. Because of the complex and dense nature of our data and our use of interpretive codes, we chose a consensus approach to coding the data.^20,21 Two team members coded each transcript independently and then discussed the coded transcript and resolved any discrepancies. The interviews and codes were entered into a qualitative computer analysis program (NVivo7; QSR International). Our qualitative analysis was guided by quantitative findings and sought to explain and confirm those findings. We also identified factors, in addition to those included in our quantitative analysis, that influenced the use of VAP prevention practices, and we explicitly sought out and highlighted examples that were contrary to expected findings, to ensure the rigor of our analysis.

Quantitative Survey

The survey response rate was 72%. Table 1 shows the characteristics of the responding hospitals. In our sample, 83% of the hospitals reported regularly using semirecumbent positioning, 40% regularly used antimicrobial mouth rinse, 21% regularly used subglottic secretion drainage, and 18% regularly used kinetic beds.

Table 1.  Characteristics of Hospitals Responding to a Survey Determining Practices Used to Prevent Ventilator‐Associated Pneumonia

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Multivariable logistic regression analysis (Table 2) revealed that hospitals participating in a collaborative were more than twice as likely to use semirecumbent positioning (OR, 2.6 [95% CI, 1.44–4.80]). Higher nurse‐staffing levels also appeared to be associated with the use of semirecumbent positioning (OR, 1.8 [95% CI, 0.91–3.58]), although this association was not statistically significant ( ). Finally, if the ICP was certified in infection control, the facility was significantly more likely to report regular use of subglottic secretion drainage (OR, 2.4 [95% CI, 1.21–4.65]). None of our measured characteristics were associated with use of kinetic beds or antimicrobial mouth rinse.

Table 2.  Results of Multivariable Logistic Regression Analysis to Determine Regular Use of Practices to Prevent Ventilator‐Associated Pneumonia

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Qualitative Themes

The characteristics of the 14 hospitals where telephone interviews took place and of the 6 hospitals where in‐person interviews took place that were included in the qualitative phase of the study are shown in Table 3, and the characteristics of all interviewees are shown in Table 4. Of particular interest with regard to our quantitative data was the contrast between the use of semirecumbent positioning and the use of subglottic secretion drainage, because, according to the CDC guidelines for preventing healthcare‐associated pneumonia, implementation of both practices is suggested and both are supported by suggestive clinical or epidemiologic studies or by strong theoretical rationale (ie, category II recommendations).³ Thus, we used qualitative data to identify underlying mechanisms that would help explain these results. The following 3 themes emerged from the qualitative analysis: (1) the use of collaboratives and practice “bundles”; (2) nurse‐staffing levels and the role played by nurses in the use of infection controal practices; and (3) the perceived level of evidence supporting a practice.

Table 3.  Characteristics of the Hospitals Where Interviews Took Place to Understand Regular Use of Practices to Prevent Ventilator‐Associated Pneumonia

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Table 4.  Characteristics of the 86 Hospital Staff Members Interviewed to Understand Regular Use of Practices to Prevent Ventilator‐Associated Pneumonia

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Collaboratives. Qualitative analysis confirmed the association between the participation in a collaborative and the use of semirecumbent positioning, but it revealed no association between collaborative participation and the use of subglottic secretion drainage. In particular, participation in a collaborative was identified as positively influencing the use of semirecumbent positioning, by focusing attention on the practice and by encouraging systematic monitoring, feedback, and reinforcement. A physician administrator at one hospital stated that “for many years people have tried to…advocate for semirecumbent positioning but it’s always been sort of a flavor of the month…the [collaborative] initiative began to focus on how to hardwire some of these not totally exotic practices…” A nurse at another facility noted that “…it wasn’t until the [collaborative] that all the intensivists were fully behind the whole project…once the graphs started going up, once people started seeing results, it was just part of their normal daily practice.”

Nurse staffing. Although staffing levels were not explicitly discussed during our interviews, our qualitative analysis revealed, as suggested by our quantitative data, that nurses play an important role in the use of semirecumbent positioning. Likewise, there was essentially no mention in our interviews of the active involvement of nurses in the use of subglottic secretion drainage. When describing the use of semirecumbent positioning, the interviewees identified nurses as key facilitators at several hospitals, although a few also mentioned nurses as barriers to the practice (often due to nurses' resistance or misperceptions).

While describing the role of nurses in successfully implementing the use of semirecumbent positioning, a chief of staff noted that “…the nurses are really outstanding and they…actually make it [semirecumbent positioning] happen…it doesn’t depend on the vagaries of which attending is on call.” Similarly, when asked who promoted the use of semirecumbent positioning, a nurse at one facility stated that “…it was just the nursing staff, the charge nurses, it was me [a nurse] going around talking about it.”

Although nurses were identified as key facilitators, they were also described by some as potential barriers to the regular use of semirecumbent positioning. The nurse manager of a medical ICU explained how she encountered resistance from some nurses: “…many of my nurses have been here many years…so when you have evidence‐based practice and you have to make changes, it’s just hard switching.” In addition, nurses’ misperceptions were another common issue. As described by an ICU nurse, “…probably the biggest challenge was that the nurses thought that they were already putting the head of the bed up 30° but if you looked at the angle of the bed it was only 20.”

Nurses also facilitated the use of this practice (ie, semirecumbent positioning) by regular monitoring. One nurse described how she and other staff nurses would ask why the head of the bed was not up, thereby becoming, as she phrased it, “the head of the bed police.…” However, other professional staff were also involved in monitoring this practice at some hospitals. For example, a respiratory therapist described how a pharmacist became involved with monitoring: “he was checking off all of these items…he started out with just the sedation and the weaning protocol and, he thought well, I may as well add that [monitoring head of bed elevation].…”

Perceived level of evidence. None of our respondents described any debate about the evidence supporting semirecumbent positioning to prevent VAP. As the director of a medical ICU observed, “something like head of bed, you’d say, there’s no downside.” This general acceptance, with little discussion of the evidence, is in strong contrast to how decisions to use or not use subglottic secretion drainage were made at several hospitals. An ICP at one hospital that was not using subglottic secretion drainage explained that “there certainly is interest by our intensivists…they think it shows promise…[but] they’re not convinced there’s definitive evidence that it prevents VAP.” At another hospital, a critical care physician explained the lack of use of subglottic secretion drainage this way: “Well because I think if you look at the literature, it’s a little bit questionable and it really looks like oral decontamination by frequent mouth washing is probably sufficient.”

At hospitals using subglottic secretion drainage, it was often used only for certain patients or on a trial basis, and, even at these hospitals, the perception of the evidence was mixed. The hospital epidemiologist at one hospital that had used subglottic secretion on a trial basis stated “I think that the recommendations in the CDC guideline…might be a tad more enthusiastic than the number of studies and the data actually support.” When asked about why they were using subglottic secretion drainage, a physician explained “I think a series of articles over the years that suggested they significantly reduced VAP. It was the biologic plausibility that made sense.”

Other reasons for not using, or for selectively using, subglottic secretion drainage were cost and mechanical issues, such as tube rigidity. However, as one physician noted, “if you look at them, they’re not that expensive…so I don’t think honestly that that’s a very strong argument, although it is the argument that everyone raises.” Furthermore, in several cases, the concerns expressed were based on hearsay and not personal experience. For example, as described by a physician, “I’d heard from everybody I’d asked that these [subglottic secretion drainage endotracheal tubes] were hard to keep patent, to make actually work, that they took a lot of tinkering…they kept clogging and it was like a nightmare.”