Our results suggest that the use of a nurse-led program based on Johnson's model can improve system equilibrium when individualized comprehensive care is provided even for patients undergoing CABG surgery. According to these results, the intervention based on Johnson's behavioral model reduced the patient's problems in terms of the affiliative sub-system. In their study determining the effect of a nursing care program using Johnson's behavioral system model in heart failure patients in Mashhad hospitals in 2020, Rahmani et al. observed no significant change in the two intervention and control groups as far as the affiliative subsystem was concerned [16], which is not consistent with the results of the present study. This discrepancy could be explained by a number of factors such as different research populations, intervention methods, lengths of intervention, care environments, and patients with different problems.
The intervention in the present study also reduced the patient's problems in terms of the subsystem of aggressive-protective. These results are in agreement with those of Ghanbari Afra and Mohammad Hoseini who conducted a case study evaluating the effect of Johnson's behavioral system model on the care of a patient with heart failure in a hospital affiliated to Qom University of Medical Sciences. They showed that after using Johnson's model, the patient's unstable behaviors were reduced in terms of the aggressive-protective subsystem [19]. Johnson's behavioral system model emphasizes the evaluation of, and intervention with, the individual's behavioral system in a non-invasive manner. Therefore, in order to improve the disease symptoms, nursing interventions such as providing the patient with an opportunity to talk about their anger and using family support can reduce patient problems in this subsystem.
Based on the findings of the present study, there was a decrease in the patient's problems with regard to the dependency subsystem. In line with the results of our study, Karkhah et al. reported improvement in the dependency subsystem as a result of a nursing care program based on Johnson's behavioral model in a patient with hematoma of the wrist joint who was admitted in Poursina Hospital in Rasht, Iran, in 2020 [20]. Suffering from heart disease is a source of stress for the patient and the family, and as a critical condition, it can disrupt the functioning and dynamics of the individual and the family. The nurse's reaction to the disease has therefore a profound effect on the patient's health and ultimately their recovery.
Our results also showed a reduction in the patient's problems with respect to the eliminative subsystem. Nooraldini et al. studied the effect of a nursing process based on Johnson's behavioral system model in stroke patients, and detected inefficiency in the eliminative subsystem, which was related to the side effects of drugs causing constipation. Their nursing interventions included training on the consumption of laxative foods, increasing fluid intake to 6–8 glasses per day, drinking one glass of water on an empty stomach, walking for 30 minutes daily, and taking laxatives as prescribed by the doctor. At the end of the two-month period after the nursing intervention, the patient experienced improvement in terms of the eliminative subsystem and was able to control urine and feces [21], which is in line with the results of the present study.
According to the results of this study, the patients' problems regarding the ingestive subsystem were reduced. In Karkhah et al., the interventions performed to diagnose anorexia included the following: checking the patient’s nutritional status, water and electrolytes, checking the patient's weight, asking the family for help in decorating the patient's food, and encouraging the patient to frequently consume food in small quantities. Based on their results, the patient's unstable behaviors regarding the ingestive subsystem were reduced following the use of Johnson's behavioral system model [20], which is in line with the results of the present study. Disease-associated malnutrition has detrimental effects on the healing process, leading to an increase in infection, delayed recovery, prolonged hospitalization, increased hospital costs, and mortality. Since the ingestive subsystem is concerned with the patient's ability to drink and eat sufficient liquids and food, have a proper appetite, and obtain dietary and medicinal information [22], it improves the nutritional status of the individual.
Based on the findings of the present study, the patient's problems were improved in terms of the restorative sub-system. Payamani et al. evaluated a nursing process based on Johnson's behavioral system model in patients with multiple sclerosis. Fatigue related to muscle weakness from doing housework and spasm was diagnosed based on the client's statement. Their nursing interventions included learning to restore energy by resting between daily activities, stopping work before excessive fatigue, not doing heavy work and activities, dividing daily tasks into 24 hours, and taking prescribed medications on time. Their results showed that after nursing interventions, the client's muscle weakness and spasm improved [15], which is consistent with the results of the present study. Fatigue is one of the most common and uncomfortable side effects in heart patients, and when it becomes severe, it has an immense impact on daily functioning and quality of life. To manage fatigue, pharmacological and non-pharmacological interventions are performed. Johnson's behavioral system model is widely used as an effective non-pharmacological treatment in heart patients.
The results of our study showed that the patient's problems were also reduced as far as the achievement subsystem was concerned. The results of Rahmani et al.'s study showed that positive changes in the dependency sub-system in the intervention group were significantly high, which is consistent with the results of the present study. Adherence to treatment, which is defined as the extent to which individuals' behavior conforms to health or treatment recommendations, regular use of medications, and adherence to therapist recommendations, is a complex behavioral process affected by factors such as therapist interaction and health care system. Care models not only guarantee the targeted, regular, controlled and effective care of the patient, but also provide the possibility of high and medium quality care by nurses [16].
Based on the results of this study, our intervention did not have a statistically significant effect on the sexual subsystem. In the study of Nooraldini et al., sexual dysfunction was diagnosed in relation to the complications of the disease (as determined by the patient's statement of decreased libido and sexual desire for the spouse). Their nursing interventions included teaching the clients to communicate verbally and non-verbally with their spouses, facilitating counseling with a clinical psychologist, and counseling with the spouses. Their results showed that at the end of the two-month period after the nursing process, the patient had improved in matters related to sexual activities, which is not consistent with our results [21]. This discrepancy can be explained by the fact that Nooraldini et al.'s study was a case report while ours is a clinical trial. The purpose of the sexual sub-system is to generate expectations in sexual relations, and its task is to expand the self-concept with sexual self-identity. Like all other subsystems, this subsystem changes constantly due to maturity, experience, and learning [23].
In the current study, the restorative sub-system was affected by the intervention more than other sub-systems. It seems that Johnson's behavioral systems model can help increase the restorative subsystem of patients by performing interventions such as "enhancing the ability to control and manage fatigue", which becomes the basis for regaining their strength.
It important to note that the present study suffered from a number of limitations including the small sample size and conducting the intervention in only two hospitals, which may affect the generalizability of our findings. Therefore, similar studies using larger sample sizes and being conducted in multiple settings is recommended.
Implications for practice
One of the clinical implications that emerged from this study was that nursing care should include support, nurturing, restraint, inhibition, and facilitation, as these improve the behavioral system as a whole. A second clinical implication is to provide care based on the importance and severity of changes in the equilibrium state of each human behavioral subsystem since these changes ultimately affect the entire behavioral system.