INTRODUCTION

Heart failure (HF) is a syndrome characterized by signs and symptoms such as dyspnea, fatigue and edema, which lead to decreased exercise tolerance, greater functional dependence and impaired performance in activities of daily living (ADL), as well as limitations in social life and, consequently, decreased quality of life^1-5.

HF has a significant economic impact due to the high cost of treatments, the person's disability and lack of productivity, as well as high mortality rates^6,7. It affects an estimated 20 million people worldwide, with a predicted 25% increase in prevalence by 2030, and a doubling of the inherent costs is expected⁸. It represents in Portugal more than 50,000 hours of hospitalization, corresponding to about 12% of in-hospital deaths⁹.

HF is classified according to the patient's functional status using the New York Heart Association (NYHA) scale^10,11 into 4 classes, according to table 1.

The treatment of HF is multifactorial, including a wide variety of pharmacological therapies and non-pharmacological interventions, such as cardiac rehabilitation (CR). CR can be defined as a sum of activities that favorably influence the underlying causes of cardiovascular disease, so that the patient can effectively manage their therapeutic regimen and achieve functional, psychological and social maximization, in order to resume their role in society ^12-14.

Physical exercise (PE) is a safe, afordable and viable therapeutic resource, being a crucial component of CR. According to the recommendations of the European Society of Cardiology, patients with HF should be included in aerobic training programs, in order to promote their functional capacity (FC) and improve the characteristic symptoms of HF^1,4,13. The performance of regular physical activity in people with stabilized chronic HF is directly related to the decrease in cardiovascular mortality, improvement quality of life, decrease hospitalization rates and even reduced intolerance to physical exercise itself, being essential its inclusion in the daily clinical practice of all centers that provide care to patients with HF ^4,13,15. Aerobic training (AT) is the best-founded training typology for the treatment of people with chronic HF^1,10,11, and there is no minimum beneficial limit for it, that is, the minimum amount of exercise performed by the patient will always benefit from not performing any type of training or physical activity¹. The beneficial effects of PE are related to the improvement of cardiovascular and respiratory function, that is, increased maximum oxygen consumption, decreased myocardial oxygen consumption, decreased blood pressure (BP) and heart rate (HR) at rest, increase in the threshold of anginal symptoms and lameness, as well as control and reduction of cardiovascular risk factors (CRF)^16,17.

The PE prescription is based on Frequency, Intensity, Time and Type of exercise (FITT), which must be adjusted according to the type of care (inpatient or outpatient), the stage of the disease (acute or chronic) and the limitations or motivation of the person^10,17. Despite all the benefits and recommendations for its application in an inpatient context, PE training is however largely underused¹⁰, and there is still not enough reasoning to prove its level of effectiveness and safety when implemented in people hospitalized for decompensated HF.

Some of the factors that lead to this underutilization are related to the physiological limiting mechanisms characteristic of the disease, namely the decrease cardiac output, decrease contractility, diastolic impairment, increase peripheral vascular resistance, mitral regurgitation, chronotropic incompetence, inadequate distribution of the blood flow to skeletal muscle and endothelial dysfunction. All these physiological characteristics of HF compromise the performance and effectiveness of PE training; however, it is known that regular PE training promotes the reversal of most of these mechanisms by the autonomic modulation it produces, contributing not only to promote an increase in PE tolerance but also to improve the patient’s prognosis^18,19.

During the training session, there are numerous physiological responses that must be monitored in order to ensure the patient's safety. Thus, the following situations constitute clinical risk criteria: 1) diastolic blood pressure (DBP) ≥110 mmHg; 2) decrease in systolic blood pressure (SBP) > 10 mmHg during PE with an increase in its intensity; 3) significant ventricular or atrial arrhythmias, with or without associated signs/symptoms; 4) second or third degree atrioventricular block; 4) signs/symptoms of PE intolerance, such as subjective perception of effort (SPE) greater than 8 on the modified Borg scale, angina, severe dyspnea and changes in the electrocardiogram (ECG) suggestive of myocardial ischemia^15,17,20. In addition to these recommendations, the existence of falls and any muscle damage, such as adverse events resulting from PE training, should also be considered.

Thus, it is understood the importance of PE training in promoting the patient’s FC and also as a supporting mechanism to the treatment and clinical stabilization, and it should be implemented whenever possible and using adequate monitoring.

The purpose of this case study is to assess the safety and effectiveness of an exercise training plan targeted at a complex cardiac patient.

METHODOLOGY

Case study based on the guidelines of CAse REport (CARE), since they allow the design of a more logical and clear case study structure, presenting a proposal for its organization in several relevant items. The items were fulfilled and the necessary adaptation was made to the case in question²¹.

The data presented refer to a person admitted due to decompensated heart failure in a hospital in the northern region of the country, belonging to the District of Porto; which was part of a longitudinal study of the randomized experimental type. The patient in question proved to be a particular case of interest as, during the initial training sessions, his HR always exceeded the defined safety limits. However, according to a team consensus, it was decided to keep training with adequate surveillance, in order to assess its effectiveness in cardiac modulation and increase in functional capacity. In an initial phase, this patient quickly reached HR values ​​of around 140 bpm, which is an indication to interrupt training, however we understand that if we did so, we would greatly limit the progression in training and compromise the functional gain expected from the performance of physical exercise training. In the aforementioned study in which the patient is inserted (ERIC-HF: Early Rehabilitation in Cardiology - Heart Failure), the participants are submitted to an aerobic training protocol with progressive levels of intensity, during the hospitalization period. Functional capacity is assessed at admission using the Barthel Index (BI) and London Chest of Daily Living Activities (LCADL) and at discharge with the same instruments, plus the 6-minute walk test (P6MM). The progression through the physical exercise program is evaluated based on the recording of the training volume performed, namely the number of laps performed on the trademill, the number of meters walked and the number of steps covered, according to the training protocol (Table 2) with the time spent in each training session also being registered.

The criteria for inclusion in the study are 1) being over 18 years-old; 2) hospital admission for decompensated heart failure and 3) ability to provide informed consent.

As this is an intervention in patients in the clinical stabilization phase, exclusion criteria for the implementation of the training program were defined. These criteria are manifested as temporary, that is, if the clinical condition that determines the non-start of the training program is resolved, the person can restart the training protocol again: 1) osteoarticular pathology compromising exercise performance; 2) inotropic drugs in perfusion; 3) dysrhythmias and/or precordial pain in the last 24 hours; 4) acute pulmonary edema in the last 12 hours; 5) SBP > 180 mmHg or <80 mmHg; 6) need for continuous oxygen therapy > 3 l/min; 7) glycemic decompensation in the last 12 hours.

All data protection rules and obtaining free and informed consent were complied with. The aforementioned study is authorized by the ethics committee of the hospital where it is decorated and is registered on the clinicaltrials.gov platform with the identification number: NCT03838003.

To describe the data, the Microsoft Excel program was used, namely to build the tables and graphs.

CASE PRESENTATION

Rehabilitation Nursing Assessment

In order to assess the functional status and degree of management capacity of the therapeutic regimen of Mr. F.S: 4 instruments were used at different times, namely: BI, LCADL, T6MM and Heart Failure Self-Care Scale (EAIC).

The LCADL scale is assessed on admission and every 2 days until discharge, in order to measure the impact that dyspnea - the main symptom of HF - has on the person's ADL performance^22,23.

The BI was assessed at admission and at discharge, allowing for the identification of other self-care limitations not resulting from HF^(24.25).

The T6MM was implemented as soon as the patient presented aerobic capacity to perform it, being repeated at the time of discharge, in order to assess the evolution of their functional capacity. This is an easy-to-administer, cheap and safe test that allows you to assess submaximal functional capacity. The person should walk at the maximum possible speed^26,27; however, since ADL are not performed at maximum speed, in an inpatient context, the person can walk at their usual speed, as some researchers have tested^{(28 -30)}. It should be noted that gait ability is a reliable indicator of functional capacity^26,31.

The EAIC was only assessed on admission as it allows understanding the degree of knowledge that the patient has about their clinical condition as well as the strategies use to keep themselves as healthy as possible, ending with an assessment of the person's perception of their ability to assess their overall health status. The use of this instrument allows the rehabilitation nurse to identify which areas of Knowledge and Learning Skills should be worked on³².

Since the main rehabilitation intervention in this clinical situation focuses on aerobic exercise training, hemodynamic parameters are also evaluated allowing the assessment of the degree of clinical safety for performing the various exercises, as well as determination of the intensity of the training to be performed. These parameters correspond to the safety indicators previously mentioned, namely: systolic and diastolic blood pressure (before and immediately after the end of the training session), heart rate HR at rest and during training (with special attention to the maximum value of HR reached), SPE at rest, during training and at the end of it. In addition to these parameters, it was also verified in all training sessions the existence of some of the previously defined exclusion criteria.

Rehabilitation Nursing Diagnoses

The rehabilitation nursing diagnoses inherent in this clinical case were defined respecting the language of the International Classification for Nursing Practice (ICNP®) version 2015³³; however some of the focuses used are not yet parameterized, so the inherent interventions they are not fully described according to CIPE. The following are focuses of attention and respective rehabilitation nursing diagnoses:

Rehabilitation Nursing Interventions - aerobic exercise training protocol

The interventions described below refer mostly to the training plan carried out by Mr. F.S., as well as the evolution data throughout it. Several identified diagnoses (Table 3) result from the person's physical deconditioning and, as such, their resolution is largely related to the improvement in functional capacity resulting from exercise training.

The identified focuses of attention, namely 1) ventilation, 2) activity intolerance and 3) Self-care physical activity, are closely linked to each other and the resolution of formulated diagnoses, producing health gains sensitive to rehabilitation nursing care, are essentially due to the exercise plan implemented. The ventilation focus is the most relevant at an early stage, since if ventilation is compromised it will not be possible to progress in the intensity of the training plan, as oxygen supply is essential for good exercise performance and how such resolution of the diagnosis “compromised ventilation” requires immediate attention, resorting to functional respiratory re-education. After optimizing ventilation, it is possible to progress in the training plan, promoting the resolution of the diagnosis "high degree of activity intolerance", since the person will be able to obtain better physical conditioning by performing the ADL in an increasingly autonomous and unrestricted manner. , being later possible to reach higher levels of aerobic capacity, contributing to the resolution of the diagnosis "compromised physical activity self-care", whose functional content is related not only to physical capacity but also to the promotion of knowledge about exercises and their benefits .

The implementation of an exercise plan necessarily implies its planning, in accordance with internationally defined prescription criteria¹⁷. In this way, the planning of the implemented training protocol is presented (Figure 1):

Figure 1 Training protocol implemented 

The implementation of the exercise protocol took place after the first 24 hours of hospitalization, and the patient signed an informed consent for this. In each session, the clinical safety criteria were always verified, as well as the criteria previously defined as exclusion. As this is a training program that takes place during the clinical stabilization phase, it was not always possible to implement the 2 sessions daily for clinical reasons, namely fasting for diagnostic exams or even refusal by the person on certain days.

It should be noted that the relevance of this clinical case is centered on the fact that Mr. FS has performed most of the training sessions with HR values ​usually outside the parameters defined as standard, however the implementation of this training protocol was targeted of consensus of the multidisciplinary team (nurses, specialist nurse in rehabilitation nursing and assistant physician) and with its implementation, the modulating effect of physical exercise on HR was notorious.

RESULTS

The implementation of the aerobic training protocol, integrated in the aforementioned research study, allowed the sick person to improve their functional capacity and, consequently, resolve the altered nursing diagnoses. Concomitantly, and this being one of the most relevant aspects of this clinical case, the effect of cardiac modulation by exercise was noticeable. The importance of this effect is linked to the fact that the maladjusted chronotropic response is a limiting factor to the continuity of exercise, namely, a HR value above 30 bpm compared to the value at rest is an indication to discontinue the exercise. In this clinical situation, the intention is precisely to modulate the HR by exercise, since the pharmacological measures would not be fully effective, in order to allow the sick person to improve their FC.

The planning of the sessions with the respective volume of training performed is presented below, as well as the vital parameters evaluated - important in determining the intensity of the training and its safety (Table 4).

According to the data presented in Table 4, it is verified that Mr. FS performed bidaily training on most days, reaching a progressively greater training volume and exercise time in each session, maintaining a speed of about 3km/h on the march. Regarding the hemodynamic parameters directly related to training safety - BP and HR - there is a tendency for the SBP values ​​to decrease after training, as well as the maximum HR during exertion. It should be noted that the patient in question was not on negative chronotropic medication. The subjective perception of exertion measured by the modified Borg scale is manifested in a range of values ​​considered as mild to moderate (0 to 4).

For a better interpretation of the results, two graphs representing the volume of training performed are presented below, namely the number of meters covered (Graphic 1) and the variation in HR at rest and during effort (Graphic 2).

Graphic 1 meters covered during training. 

Graphic 2 HR variation at rest and maximum 

Observing the above graphics, a positive progression in training volume can be seen: progressively higher number of meters covered, adding stair training, also with a positive trend. By analyzing the second graphic, it is possible to identify two important findings: the decrease in HR on exertion and the approximation of this value to the value at rest, revealing a smaller range of values.

During hospitalization, the patient underwent 2 gait tests, one on the 1^st day, being able to walk for 6 minutes, occurring on the 4^th day of hospitalization and the second on the date of discharge. The results are shown in Table 5:

It can be verified, by analyzing Table 5, a positive difference between the 2 tests, of 85 meters, as well as a negative difference in the subjective perception of effort of 2 values. Also HR and TA values show a decrease between the 2 tests.

DISCUSSION

Based on the results presented, it is clear that the implementation of the ERIC-HF training protocol in Mr. F.S. may have been decisive in the modulation of HR, also promoting an improvement in his functional capacity measured by the T6MM.

The effect of aerobic training on the autonomic nervous system translates into a modulation of HR, that is, an adaptation of muscle fibers and sympathetic stimulation during activity, so that an unreasonably high HR is not reached, thus compromising the cardiac function and consequently the effectiveness of training³⁴. Several studies have analyzed this modulating effect of exercise in patients with stabilized HF; however, there is no evidence in relation to patients undergoing clinical stabilization. However, we can verify that this effect is also likely to occur in patients in an inpatient context, contributing this as another factor that corroborates the beneficial effect of exercise training.

Clearly, the pharmacological therapy implemented during hospitalization allows contributing to the patient's clinical stabilization; however the drugs administered to this person have no potential effect in terms of HR modulation, since were not prescribed beta-blockers or other drugs with negative chronotropic effect.

Regarding functional capacity, the difference of 85 meters in the distance walked between the 2 tests performed by the patient translates into a considerable improvement, which we can classify as clinically significant^35-38. Walking ability is accepted as an excellent indicator to infer autonomy in performing ADL and consequently infer about their functional capacity.

The joint analysis of these hemodynamic and functional parameters, such as HR and FCmeasured by the T6MM, are fundamental to understand that even in a phase of clinical instability, the specialized and differentiated intervention of the rehabilitation nurse can be decisive, especially in patients with pathologies that limit self-care such as HF.

Despite the evidence of a significant gain in functional capacity and the verified cardiac modulation, it is important to carry out the analysis of other similar clinical cases in patients included in the aforementioned study, so that it is possible to verify whether it is in fact a trend or whether these results may be associated with specific individual characteristics of Mr. FS

FINAL CONSIDERATIONS

This case study allowed us to validate the effectiveness of the rehabilitation nursing interventions in this patient, within the scope of the planning and implementation of physical exercise training aimed at cardiac patients undergoing clinical stabilization. Since the competence in physical exercise is included in the profile of the specialist nurse in rehabilitation nursing, it is essential to develop more rehabilitation programs in this direction and with evidence of health gains for the patient, sensitive to nursing care.

Throughout the implemented program, it was essential to assess the patient's progress in terms of exercise tolerance and autonomy to perform activities of daily living, due to a reduced sensation of dyspnea. It was essential to monitor these gains through the various functional assessment instruments, and it was also essential to strictly record the various training sessions, with regard to the volume, frequency and type of training performed by the patient, as a way of confirming the rigor of the planning of the exercise.

No adverse events arising from the implementation of the training protocol were recorded, thus revealing the safety of the implemented rehabilitation care, according to the previously defined planing.

More studies are needed and with more numerous samples, in order to unequivocally validate the impact that physical exercise training can have on cardiac modulation and on the promotion of functional capacity.