Knowledge of pressure ulcer prevention: a cross-sectional and comparative study among nurses

Pressure ulcers are a common problem in health care and represent a significant burden on patients, their relatives and caregivers [1, 2]. Annual national prevalence surveys, conducted since 1998, indicate that an average of 18.1% of the patients in hospitals in the Netherlands suffer from pressure ulcers [3, 4]. Recent studies conducted in Europe, the United States, Canada and Australia have provided estimates of pressure ulcer prevalence in hospitals ranging from 8.3% to 25.1% [5‐9]. The costs of prevention and treatment of pressure ulcers are considerable [10, 11]. Estimations for 1998 revealed that more than 1% of the health care budget in the Netherlands was spent on pressure ulcer care. Hence, prevention and proper treatment deserve greater attention [11].

Various preventive measures are being used in nursing practice [1, 12]. To address the prevention and treatment of pressure ulcers in a more systematic way, a set of national guidelines based on expert opinions was developed in 1985, and revised in 1992, by the Dutch Institute for Health Care Improvement (CBO) [13, 14]. Despite nurses' positive attitudes towards pressure ulcer prevention [15], various studies have revealed a gap between theory and practice [1, 16, 17].

In 1991, Eggink investigated this gap between theory and practice by assessing nurses' knowledge of the 1985 Dutch national guidelines [18, 19]. Although knowledge among health care staff is in itself not enough to ensure implementation of guidelines, it is a prerequisite, along with insight and skills, for the implementation process [20]. The results of the study by Eggink [18] confirmed earlier research revealing that the usefulness of the preventive measures considered in the 1985 national pressure ulcer guideline was insufficiently known among nurses employed in Dutch hospitals. Preventive measures that were not evidence-based were nevertheless still being applied, and sometimes interventions that are known to be useful to prevent pressure ulcers were withheld from patients who needed them. Various other studies have confirmed the lack of knowledge about pressure ulcer prevention. Pieper and Mott [21] showed that registered nurses had insufficient knowledge about pressure ulcers, and Panagiotopoulou and Kerr [22] showed that nurses' average level of agreement with expert opinion regarding the value of preventive measures was a mere 50%. Despite the publication of research findings that support the importance of using evidence-based guidelines, studies have found that guidelines are frequently not implemented and nurses' performance is often based on intuition, experience or habit [23‐25].

Because the 1985 and 1992 national guidelines were based on expert opinions rather than evidence, there has been a growing debate about the usefulness of preventive measures. In 2002, a new national set of guidelines was published, based on evidence and expert opinions [12].

Increased consideration is currently being given to pressure ulcers in the Netherlands, as a result of the development of updated pressure ulcer guidelines, publications in professional journals, increased involvement of nurse specialists for pressure ulcers and the implementation of the Annual National Prevalence Pressure Ulcer Surveys [3, 4]. In addition, Halfens et al. [26] showed that participation in the Annual Prevalence Surveys resulted in organizations engaging in activities to improve the prevention and treatment of pressure ulcers. Bours et al. [27] described the positive effect of monitoring pressure ulcers each year and giving feedback to hospitals on the use of effective preventive interventions.

These developments might be expected to have resulted in health care institutions and nurses being familiar with the value of preventive measures. In this study, we investigated the development of nurses' knowledge in this respect, to assess whether it has changed over time and whether being employed in an organization that is auditing pressure ulcer prevalence influences nurses' knowledge. The following research questions were formulated:

1. What do nurses employed in Dutch hospitals know about the value of the preventive measures for pressures ulcers considered in the 2002 Dutch Guideline on Pressure Ulcers?

2. Is there a difference in knowledge about the value of the measures to prevent pressure ulcers considered in the 2002 Dutch Guideline on Pressure Ulcers between nurses employed in hospitals that participate in the Annual National Prevalence Surveys and nurses employed in non-participating institutions?

3. Is there a difference between the knowledge among nurses employed in Dutch hospitals in 1991 and those employed in 2003 as regards the value of the preventive measures for pressure ulcers considered in the Dutch Guideline on Pressure Ulcers?

The present study used a cross-sectional design to examine current knowledge among nurses regarding the usefulness of measures to prevent pressure ulcers. In addition, a comparative design was used to assess whether nurses' knowledge had changed between 1991 and 2003. Secondary analyses were conducted to test whether nurses' knowledge about the usefulness of preventive measures used the same classification as that used in the national guideline.

The results of the present study show that the knowledge among nurses employed in Dutch hospitals about the usefulness of preventive measures mentioned in the national Guideline on Pressure Ulcers [12] is moderate. Knowledge about non-useful measures in particular seems to be poorly disseminated, whereas useful measures are better known among nurses. In addition, we found that being employed in a hospital that monitors pressure ulcers annually does not lead to better knowledge about preventive measures.

Comparing our results with a similar study conducted in 1991 [18, 19], we can conclude that despite the increased attention and new developments in the area of pressure ulcer care, knowledge about useful measures has not greatly increased. A considerable number of nurses still evaluated useful measures incorrectly in 2003, and the knowledge about non-useful measures had actually decreased. Against our expectations, results showed that the usefulness of a few measures was better known in 1991 than in 2003. Apparently, nurses in 2003 were not aware of the changes in the guidelines regarding the usefulness of these measures, which in the 1985 Consensus on Pressure Sore Prevention were regarded as 'sometimes useful', while in the 2002 version they are regarded as 'not useful'. Nurses' judgements on these measures in 2003 were comparable to those of the nurses in 1991. It seems likely that the nurses in the 2003 sample had not familiarized themselves with the updated guidelines or had not received up-to-date information about pressure ulcer prevention.

We used a 70% cut-off point (i.e. judging 70% of the measures correctly) to identify nurses having sufficient knowledge, which could be regarded as mild. Even at this cut-off level, however, only a small number of nurses met the criterion. A higher cut-off point, making the criterion stricter, would have led to even more nurses being labelled as not having sufficient knowledge. Nevertheless, the results obtained with the current cut-off point give some indication of the level of knowledge.

Apparently, the efforts to disseminate knowledge about the prevention of pressure ulcers have not led to major improvements in knowledge. Although it might be thought that the difference in the percentage of nurses with sufficient knowledge could be explained by demographic differences between the 2003 and 1991 study populations, logistic regression analyses showed that none of the demographic variables had a significant influence.

Our figures may even overestimate the nurses' actual knowledge. It is known that postal surveys are susceptible to positive selection bias [28, 29], and respondents tend to differ from the underlying population [30]. In view of the response rate and composition of the sample in the 2003 study and the difference in availability and coverage of the Verpleegkunde Nieuws professional journal between 1991 and 2003, it seems likely that it was especially the more interested nurses who responded in the 2003 study, which may have resulted in a biased impression of the knowledge of nurses in general. The average actual knowledge among all nurses is therefore probably poorer. Nevertheless, the results give some idea of the knowledge among nurses employed in hospitals.

Results of the present study confirm those of Pieper and Mott [21] and Panagiotopoulou and Kerr [22]. Sinclair et al. [31] and Gunningberg [32], who assessed the knowledge among nurses before implementing an educational programme, also reported that knowledge regarding pressure ulcer prevention among nurses was moderate.

With hindsight, use of the term 'viscoelastic mattresses and pillows' may have caused information bias. A considerable proportion of the nurses answered 'don't know' to this question, or did not answer the question at all. A more detailed description or brand names of these support surfaces would probably have changed the distribution of answers and provided a better idea of the knowledge about these devices.

Principal Factors Analyses showed that a factor solution consistent with the two-category classification of preventive measures in the 2002 national guideline only explained 13.1% of the variance of the construct we measured. Streiner and Norman [33] provide an explanation for these outcomes. Whereas in most situations, measured variables are defined by the construct and are expected to be correlated, in our study it was the variables which defined the construct: the knowledge about usefulness was defined by the individual questions about preventive measures. Despite the low degree of explained variance, the specific variables do matter. Our Principal Factors Analyses therefore have to be regarded as confirmatory, in that they were intended to test whether nurses' knowledge had the same classification as the classification used in the national guideline. Another explanation for our findings could be the poor agreement in judgments about the usefulness of preventive measures. A result showing more convergent validity would probably have been obtained if nurses' opinions about usefulness had been more homogeneous.

Apparently, the preventive measures recommended in the guidelines are not very well known among nurses. Pressure ulcer prevention guidelines rarely seem to be based on scientific evidence, but rather on expert opinion. Moreover, the dissemination of knowledge among nurses is also influenced by the known barriers to the use of guidelines, like lack of staff and time [15], and probably by the quality of the guidelines. For instance, measures such as 'using a cradle' and 'reactivation and mobilisation by paramedics' are not clearly classified as non-useful by the 2002 Dutch Guideline on Pressure Ulcers. Although experts consider them not useful, they acknowledge that they may be useful in some cases. The equivocal expert judgments regarding massage [34] and the use of sheepskins [35] cause confusion as well. Therefore, the distribution of answers (tables 2 and 3) is not surprising and the conclusions about correct judgments have to be interpreted with caution. For this reason, we recommend further research to test the effectiveness of these preventive measures and to implement more evidence-based guidelines instead of opinion-based guidelines.

The implementation of guidelines and their translation into practice remains difficult [36]. Grol and Wensing [37] stated that the process of implementing guidelines is influenced by several factors, including interest and commitment to guideline development. In 2005, Clarke et al. [38] studied which strategy would be best to effectively implement pressure ulcer guidelines. They concluded that implementing these guidelines demands a comprehensive approach. To increase nurses' knowledge about prevention of pressure ulcers, guidelines should be implemented in a systematic and meticulous way. Constant attention to prevention remains essential. In the Netherlands, the government has taken an important step by considering the presence of pressure ulcers as a quality indicator of care. With adequate policy and management, awareness among health care organizations of the need to reduce the prevalence of pressure ulcers will hopefully affect the level of awareness among their staff. However, based on the present study and the research by Buss et al. [23], which found that nurses do not seem to have the intention to change their preventive actions, we recommend further research to study which tailored approach would help change nurses' knowledge, beliefs and performance regarding pressure ulcer prevention. Potentially useful interventions in this respect include education and refresher courses for nurses in the context of a comprehensive approach.

In conclusion, Dutch hospital nurses' knowledge regarding the usefulness of measures to prevent pressure ulcers seems to be moderate. Being employed in an organization that monitors pressure ulcer care hardly affects this knowledge. Besides, knowledge about prevention has not improved over time. Apparently, activities undertaken to reduce the prevalence of pressure ulcers have had little or no effect on nurses' knowledge. Adequate dissemination of pressure ulcer prevention guidelines seems a prerequisite to improving the quality of pressure ulcer prevention.