Educational intervention for collecting sputum for tuberculosis: a quasi-experimental study 1

Abstract Objective: to evaluate the quality of the sputum sample before and after the Nursing guidance to patients. Methods: this is a quasi-experimental research design, single group type, before and after, non-randomized study. The study enrolled patients with suspected pulmonary tuberculosis, respiratory symptomatic patients for over three weeks, aged over 18 years, of both genders and without tuberculosis history in the last two years. The educational intervention consisted of individualized guidance on the collection of sputum sample, which was based on the guidelines of the Ministry of Health of Brazil and on the explanatory folder delivery. Results: in this study participated 138 patients with suspected pulmonary tuberculosis. The results showed significant increase of the samples with purulent particles, volume greater than 5 mL and increased rate of patients diagnosed with tuberculosis, after the educational intervention. Conclusion: it was shown that after the educational intervention, it was observed sputum samples with better quality, with satisfactory aspect and volume for the effectiveness of the bacilloscopic examination.


Introduction
The early diagnosis is one of the priority strategies for the control of tuberculosis (TB), a disease that remains a serious public health problem of worldwide magnitude. Of the 5.4 million new cases reported in 2013, over 80% presented the pulmonary form of the disease (1) .
The diagnostic confirmation is based on the clinical and epidemiological history, radiological examinations, tuberculin skin test, bacteriological tests (bacilloscopy and culture), and biochemical and molecular tests (2) .
Although the expectation of expansion of the rapid test for detecting TB is high for all global health services, bacilloscopy remains the priority method, especially in developing countries, because it is simple, fast, inexpensive and, when properly executed, it allows to identify about 70% of cases of pulmonary TB (3) .
It is worth mentioning that regardless of the technological innovations introduced to diagnosis, the quality of sputum sample plays a central role, since the accuracy of any laboratory results of TB diagnosis depends on the quality of a collected sample (4) .

Accordingly, the efficiency in the detection of new TB
cases is intrinsically related to the quality of the sample and this, in turn, depends on the quality of the guidance on how to properly collect the material. In the context of TB care, the nurse has assumed an important role in the prevention and control of the disease, which ranges from actions such as identification of respiratory symptoms to discharge of the confirmed cases (6) . In this sense, the clinical nursing practice, supported by the Evidence-Based Practice (EBP), is of fundamental importance since it guides the management and care decision process of Nursing (7) . This, in turn, is based on problem identification, consensus of the relevant scientific evidence, implementation of these in professional practice and evaluation of the results achieved (8) , a process which should be in line with the preferences of the patient. Thus, the use of EBP represents a qualifier for the health care at different levels of care, resulting in a better clinical practice (7) .
This study is justified by the few evidence found (9-14) ,
It is observed that, in terms of aspect and volume of the sample, patients after the educational intervention were able to produce more samples with purulent particles and satisfactory volumes than before the intervention. This association was statistically significant. Regarding the bacilloscopic results, it was observed an improvement in the bacilloscopic diagnosis.
However, these results were not statistically significant.
The evolution in the aspect of sputum samples before and after intervention is presented in Table 2.  Table   3, it is observed the proportion of cases diagnosed per each sputum collection stage.

Discussion
The The decrease in the percentage of samples with aspect of saliva, after the intervention, was also observed in another study (12) . If the sample is inappropriate (that is, only saliva), it may not be possible to find bacilli, even though the patient is bacillipherous (6) . Thus, it is evident that after the qualified instructions, as recommended, patient is able to reduce the number of samples with aspect of saliva, which consequently reduces the probability of false negatives.
Other studies have shown the positive effect of guidelines on the quality of the sample (9,11-13) . It was identified a positivity rate from 12.0 to 15.0% higher among patients who properly received the recommended guidelines by means of protocols (9,12) .
The sensitivity of the bacilloscopy test for pulmonary TB showed significant improvement when the sample volume was equal or higher than 5mL (12) .
However, both the aspect and volume are important so that diagnostic tests for pulmonary TB present improved effectiveness.
Although the relationship between the bacilloscopic results and the intervention did not shown statistically significant difference, it is important to emphasize that, as shown in Table 3, there was a significant difference from the clinical point of view, since a single undiagnosed case has epidemiological importance on TB control and it contributes to the perpetuation of the disease transmission chain.
As shown in a recent study (17) , it is assumed that, within one year, a diseased or a bacillipherous individual can infect around 10-15 people with whom they maintained contact, because while they do not start treatment, they will continue to spread bacteria to the rest of the population. Once infected, about 5 to 10% of people develop the disease, half of them during the first two years after infection, and half of them later, depending on the immune conditions of the host and the reactivation of the bacilli from their latent state.
It is emphasized the importance of sputum collection usually carried out in two different locations.
According to the program rules, the first is performed in the health service and represents an important contribution to the initial screening of cases. The second is usually performed at home, as it raises the identification potential due to the possibility of sputum collection at better physiological conditions (greater amount of material produced during the nocturnal rest) and at better safety conditions of the individual, since this procedure is performed at home. In recent studies, it was found that collection performed in the morning leads to improved efficiency in detecting AARB than the local collection (18)(19) .
Although it was identified a percentage of 52.2% take into account the patients' heterogeneity. This reinforces the hypothesis that improvement in the quality, quantity and bacilloscopy results of the third sample is due to the intervention proposed in this study.

Conclusion
The study showed that, after the educational