The group of professionals who performed their activities in clinical care (CCU) and intensive care (ICU) units were similar in relation to all variables analyzed, showing that the sample is homogeneous, which allows making comparisons between them and infer that the results obtained may be more related to the intervention or the work environment.
The fact that most professionals in the CCU group report working very frequently in CPR situations stands out, even though it is known that CPA is more prevalent in critical units [15]. CPR situations involve emotional aspects, such as the self-confidence of the first responder, control of emotions to employ knowledge and practice [16], thus, even in a lower frequency, the occurrence of CPA in non-critical units may lead to this subjective interpretation in professionals (of acting too frequently in CPA), since it is not something long awaited by the patient’s clinical condition, usually more stable than in patients in critical units.
The results of the theoretical and practical evaluation before T1 showed that both groups had a low level of theoretical and practical knowledge in CPR. These data differ from the study that evaluated the knowledge of the nursing team in BLS and showed that the highest rates of hits were related to the highest level of education, specialization in critical areas, time of experience below five years and previous training in ACLS, while the lowest rates of hits were associated with work in non-critical areas [12].
In our study, the similarity in the level of theoretical and practical knowledge between the groups can be attributed to the characteristics of the institution. Since it is a tertiary hospital, a health reference for the surrounding region, it offers specialized care to the clinically more complex patient, requiring professionals to be more qualified, regardless of the sector they act in. This may also explain the fact that CCU professionals have the perception of acting very frequently in CPR situations.
Immediately after T1, competencies were apprehension in both groups; however, the ICU group obtained a higher knowledge score, confirming the tendency of greater theoretical support in critical care professionals. Another study also showed this difference, a mean number of 12.6 ± 3.4 questions in critical unit nursing professionals and 9.4 ± 4.4 questions in non-critical unit, after initial training [17]. The approach of contents more present in the practice of professionals working in critical care such as CPA rhythms, ventilation and compression/ventilation ratio in intubated patients may have contributed to a higher final grade. Critical care nursing professionals are related to the critically ill patient, with older age, cardiovascular diseases, using vasoactive medications, continuous monitoring and ventilation [15, 18].
The improvement of the results after T1 in both groups confirms the literature data that demonstrate the importance of training to improve CPR skills. This improvement happens due to intervention and is independent of the group being trained, because studies involving laypeople [19], students [20] and health professionals [21] also observed knowledge superior to the initial one. A study with nurses showed a significant increase in the average level of knowledge and practice after a formal training program [22].
Six months after T1, knowledge and practice decreased significantly in both groups, remaining stable, without significant reductions, until the ninth month. The fact that the ICU group had a higher score in the theoretical contents after training was not enough to ensure a difference between both over time, another aspect is that skills and knowledge also deteriorate at different levels, as observed in the discrepancy between the scores of the theoretical and practical tests.
Retaining CPR skills, even in health professionals, is challenging. A study that evaluated the impact of a formal training program certified in CPR on the knowledge and skill of nurses for a period of six months showed greater acquisition of skills immediately after training, however, after six months, there was greater knowledge retention [22]. In our study, there was greater retention for skills, and the approach of basic and advanced support elements in the written test and only of the basic support for practical simulation may have contributed to this difference.
Although some advanced support techniques improve survival, basic support interventions are determinant in increasing survival rates, because the success of resuscitation depends mainly on the effectiveness of the initial actions [7].
The knowledge scores after T2, differently from the first, were similar in both groups, and the scores were higher in relation to T1. For the practice, the T2 had the same effect in both and the scores were the same observed in T1, showing that the retraining improved the knowledge, especially that of the CCU group. Any previous training is associated with better CPR skills, as it helps in learning and fixing the contents [12, 23]. Another study indicated a positive association between the performance of participants in CPR, the frequency of training and whether CPR training was offered in the workplace [24].
The terms learning and retention are different. Learning refers to the individual's ability to grasp new information or knowledge that has been instructed by an intervention; retention refers to the ability to keep what has been learned over time [22, 25].
After six months without training, knowledge and skills have been reduced in both groups and characteristics peculiar to the work sector do not ensure differences in retention. After retraining, however, it was observed that, from the sixth to the ninth month, the CPR skills did not regress to the ICU group and at the end of nine months, this group had superior practical skills. In this sense, one may infer that greater exposure to the CPA event may have contributed to a greater retention of practice in the ICU group by the end of the study.
Professionals from non-critical sectors face CPA situations and the need for CPR less often, but this fact does not keep them from experiencing these events, thus being imperative that they also have ideal skills [12]. Moreover, it is suggested that, when CPR is performed infrequently, knowledge and skills are lost more quickly [17].
As described in the literature, knowledge and skills in CPR decay six months or even before this period and that recycling training should focus on the performance of psychomotor skills and the improvement of self-confidence and should therefore be performed every 3 to 6 months [9, 17, 26]. Nevertheless, in this study, the time of nine months was effective for both groups, since the scores remained much higher than those observed before T1.
In relation to the training strategy employed, studies have been developed, seeking to identify which training method can favor greater acquisition and retention of CPR skills, and show that training in high fidelity simulation is superior to training in low fidelity CPR mannequins [27, 28]. Nevertheless, the theoretical and practical training using low fidelity simulation improved and helped the retention of the knowledge and skills of professionals.
Our study has some limitations. First, as it was conducted in a single institution, our data cannot be generalized to different institutions and countries. Second, the small sample size. Statistically, no control was used for factors that may influence outcomes. The two groups analyzed had very similar personal and professional characteristics, despite working in different contexts. Nevertheless, the group that worked in an intensive care unit retained more practical skills in CPR, which is a very relevant fact.
The study was also conducted in a simulated environment rather than observing the nurses and nursing technicians performing CPR in a real-life situation. In addition, the teaching sessions, both theory and practice, were conducted within a shorter period of time than the AHA’s BLS course. Thus, our training program differs significantly from the AHA standard course. It was designed to be shorter to minimize disruption in service, as most of the professionals were expected to return to the work area as soon as possible.
A strong point of our study is that it shows how the retention of knowledge and skills varies with the length of training and with the work unit of professionals, and that a retraining every nine months managed to maintain knowledge at 80% and skills in 94.4% using a low-cost model, which may favor its replication in institutions with more limited resources. Another aspect is that it highlights the importance of continuing health education in CPR to maintain adequate professional performance in situations involving cardiac arrest.