Teaching chronic obstructive airway disease patients using a metered-dose inhaler

Asthma and chronic obstructive airway disease (COAD) are chronic inflammatory disorders of the airways which are usually associated with widespread airway obstruction that is often relieved by treatment. β2-adrenoreceptor agonists and corticosteriods are the mainstay of the management of this disease. The preferred route of administration of these agents is by inhalation. This allows the drug to be delivered directly to the airway with more rapid relief and fewer side effects than systemic route. The main disadvantage of metered-dose inhaler (MDI) use is that the correct use requires good technique; mainly, coordinating the beginning of inspiration with the actuation of the inhaler. Several studies indicated that 24% —89% of patients have poor technique when using the MDI.1,2 To solve this problem, detailed patient education by medical personnel has been recommended.3 In Hong Kong, physicians may tend to rely on the patients’ reading the package insert because of limited consultation time. Under such circumstances, nursing and pharmacy staff may play active roles in teaching patients using MDIs.4,5 Therefore, the aim of this study was to evaluate the ability of patients to use MDI and the effectiveness of the teaching program. METHODS All patients who attended the Out-patient Department of Tung Wah Hospital between September 2004 and January 2005 and fulfill the inclusion criteria were invited to participate in the study. The inclusion criteria includes: patients who are at least 18 years old, patients who were treated with MDIs for at least 3 months, patients who can hear a voice at conversational level and have adequate vision to receive the MDI demonstration. Patients with cognitive impairment and illness affecting ability to use the inhaler were excluded. All participants will be interviewed by one of the investigators using a standardized record form. The record form design was based on a modification of a pre-existing design.5,6 The correct use of the inhaler is categorized into nine steps: (1) remove cover, (2) shake inhaler well, (3) hold inhaler upright, (4) exhale gently, (5) place mouthpiece, (6) activate canister once at the beginning of inhalation, (7) inhale slowly and deeply, (8) hold breath at least 10 seconds, (9) breath out slowly. The participant was asked to demonstrate one full inhalation with a placebo inhaler. A score of 1 was given for each step performed correctly and 0 for each step performed inadequately or skipped. Following the initial assessment, trained staff administered the teaching program prior to reassessment. The reassessment was carried out in the same way as prior to teaching and by the same investigator. The teaching program consists of detailed verbal instruction of correct inhalation technique followed by a demonstration of the correct steps. The participant was then provided with a placebo inhaler for practice. The investigator continued to review MDI technique until the participant is able to perform all steps correctly or a maximum training period of 30 minutes has elapsed. All data were analyzed using SPSS 11.0 for Windows. Descriptive statistics was obtained for demographic variables. The dependent variable used in the analyses was correct inhaler technique immediately after instruction. Since all steps of the MDI technique are not equally important, we used a conservative definition of correct technique proposed by Gray and his colleague.7 If a patient can perform steps 6, 7 and 8 correctly, he is defined to have correct inhaler technique. For the analysis of the relationship between the demographic variables and inhalation skill, we used Fisher's exact test. Changes in pre- and post-teaching demonstration scores were performed using a paired t test. The P value <0.05 was considered significant. This study was approved by Institutional Review Board of University of Hong Kong. RESULTS Demographic characteristics Twenty-eight subjects were enrolled into the study. Table 1 summarizes the demographic characteristics of study participants.Table 1: Characteristics of subjects (n=28)Demonstration score Percent mean scores ± standard deviation (SD) before and after instruction were 61±28 and 89±11 respectively. The score after instruction was significantly higher than that achieved before instruction (P<0.001). When using the MDI, over 50% of subjects performed <5 steps correctly and only 3 subjects (11%) could perform all steps correctly. The most frequent problem being failure to coordinate actuation with inhalation and to hold breath after inhalation (steps 6 to 8). The inhaler technique was improved by counseling and the percentage of subjects performing step 6 correctly increased from 46% to 82%, step 7 from 36% to 79% and step 8 from 40% to 86% (Fig.). The number of subjects that could perform all steps correctly also increased from 3 to 11.Fig.: Percent demonstration score for each step.Univariate analysis Fifteen (66%) of the 28 subjects demonstrated correct MDI technique. Table 2 lists subject characteristics for correct and incorrect MDI users after teaching session.Table 2: Factor associated with correct MDI use after instructionIndependent variables that were significantly associated with correct user of MDI included sex and smoking status. Men were more likely to use MDI correctly: 77% of men used MDI correctly, but only 33% of women used MDI correctly. Non-smokers were more likely to have correct inhaler technique, whereas smokers were less likely. No significant association was observed between age, drinking, education level or living condition and correct MDI technique. DISCUSSION Metered-dose inhalers (MDIs) are widely used for the management of airway disease. The success of therapy depends on the correct inhaler technique. Studies reported that between 24%—89% of patients might have poor inhaler technique.1,2 The improper use of the device may be correctable with proper counseling.3 In this study, one tenth of patients who were on inhaler therapy had not received any training from a health professional. This is inconsistent with current guidelines which recommend that the inhaler should only be prescribed after patients have received training in the use of the device and have demonstrated satisfactory technique.8 The reason for this inconsistence is unclear but may be due to limited consultation time of physicians in Hong Kong. Kelling and colleagues9 also reported that physicians were generally unable to use MDIs properly despite their frequent prescription of such devices to patients. Under such circumstance, nurses and pharmacists may play active roles in teaching patients the use of MDIs. Self and coworkers10 have demonstrated that allied health professionals were effective in instructing asthmatic patients regarding the use of MDIs. Our results showed that nurses’ and pharmacists’ counseling was very effective in improving patients’ skills in use of MDIs. The mean percent demonstration score before teaching sessions was only 61 and this was significantly increased to 89 after instruction. For individual steps in using MDI, the steps most patients performed incorrectly were coordination of actuation with inhalation and to hold their breath after inhalation (steps 6 to 8). Similar results have been found in other studies.5,11 Although instruction increased the number of patients performing these steps correctly, there were still around 20% of the patients who could not perform these steps properly. Therefore we believe further instructions are needed. If the patient is unable to use MDI correctly after repeated instruction, an alternative device, such as dry powder inhaler or a spacer device, may be considered. However, because of limited counseling time and manpower, it may not be possible to recheck the inhaler technique of all patients. In such a situation, factors that are associated with correct or incorrect MDI technique may be useful in identifying high-risk patients who would benefit from further instruction. In our study, female patients and current smokers were likely to incorrectly use MDIs. Age was not a factor determining correct MDI technique in this study which is inconsistent with previous reports.12,13 However, Gray and coworkers7 showed that it is cognitive function but not age which predicts the correct inhaler technique. Since impaired cognitive function is more prevalent in older populations, the relationship between proper MDI performance and increasing age may be related to cognition but not age. Therefore, the discrepancy between our results and others may be explained by different inclusion criteria. Patients with cognitive impairment were excluded from our study but cognitive function was not controlled in other studies. Education was also not related to correct MDI technique. However, Williams and colleagues14 showed that inadequate literacy was strongly correlated with improper MDI use. This discrepancy may be explained by different teaching methods. Other investigators may rely on written or verbal materials while in this study we teach patients via demonstration. Demonstration clearly showed every step and even patients with inadequate literacy could understand. We found that men were more likely to have correct MDI technique than women. Similar results have been reported by Goodman and coworkers.15 Explanation for this finding is unclear. Gray et al found hand strength to be an independent predictor of correct MDI technique. Adequate hand strength is required to depress the canister and therefore decreased hand strength is associated with poor technique. There is a relationship between gender and hand strength. Men are more likely to have stronger hand strength than women. This may explain why women are more likely to have incorrect MDI technique than men. Smokers were more likely to be associated with incorrect MDI use. The underlying mechanism for this observation is unclear. As severity of airway disease is related to smoking, it may be disease severity rather than smoking which was associated with correct MDI technique. However, the disease severity was not assessed in our study and may require further evaluation. A few limitations of our study should be noted. First, the sample size of this study is small. Second, we used a conservative definition of correct MDI technique as proposed by Gray et al,7 which may not be accepted by other investigators. Finally, the disease severity has not been examined in the study. In conclusion, our results highlight the impact of pharmacists’ and nurses’ counseling and demonstration of the correct use of MDI. Smoking and female gender have been identified as two characteristics predicting incorrect MDI technique. Therefore, smokers and female patients may need closer follow-up.