Modulating Elements of Nurse Resilience in Population Care during the COVID-19 Pandemic

COVID-19 has significantly affected the work environment of nurses. In the face of the challenges posed by stressors in clinical practice, some nurses adapt and prove to be resilient. In the face of the COVID-19 pandemic, the nature of care itself and the new ways of working are potentially very stressful. We aim to analyze the resilience of care nurses to the psychological impact of the COVID-19 pandemic. This study is a systematic review of nurse caregiver resilience to the COVID-19 pandemic in 2021. Our search was conducted in the WOS, Medline/PubMed, Cochrane, BVS/LILACS, and Cuiden databases. The inclusion criteria were: studies published in Spanish or English; carried out from March 2020 to May 2021 on nurses caring for patients with COVID-19; and investigating the factors influencing the psychological impact, resilience, strategies to develop it, and interventions to promote it during this pandemic and others, such as SARS, MERS, or ebola. The quality of the studies and the risk of bias were evaluated following ICROMS, STROBE and AMSTAR-2 criteria. Twenty-two studies were selected. Most of the studies highlighted the presence of stressors in nurses, emphasizing those of the environment, which converged in dysfunctional responses that hurt their resilience. The most persuasive factors were social and organizational support. Coping strategies developed by nurses and especially interventions by organizations were detected as instruments to foster resilience, but have not been well researched. Resilience has a key moderating role in mitigating the psychological impact of nurses in the face of the COVID-19 pandemic.


Introduction
In 2018, the International Council of Nurses (ICN) and the World Health Organization (WHO) launched the Nursing Now movement to raise the status and profile of nurses, capping it off with the year 2020 [1]. The iconic year of nurses sees the emergence of COVID-19, an emerging infectious disease caused by the new SARS-CoV-2 coronavirus, which was first identified in Wuhan on 31 December 2019 [2]. The WHO declared the disease a pandemic on 11 March 2020 due to its rapid spread in most countries of the world [3]. COVID-19 has been a dramatic global disruption, as the global number of deceased and infected patients with this disease was 4.7 million and 229.6 million, respectively, as of September 2021 [4]. The latest ICN analysis shows that as of November 2020, the number of nurses who have died after contracting COVID-19 is 1500, as many as in World War I [5]. This figure, which Int. J. Environ. Res. Public Health 2022, 19, 4452 2 of 20 includes nurses from only 44 of the world's 195 countries, is known to be a low estimate of the actual number of deaths.
Nurses are particularly at risk of psychological problems due to the highly stressful work situations to which they are exposed; this fact can be more challenging when applied in the context of a pandemic, as working in the face of such a situation can be exhausting [6]. Currently, nurses have not only experienced an increase in the volume and intensity of their work [7] but have to adapt to new protocols and new normality. A Spanish study showed that one in seven healthcare workers tested positive for a disabling mental disorder during the first wave of the COVID-19 pandemic, such as major depressive disorder, generalized anxiety disorder, panic attacks, and post-traumatic stress disorder [8]. In previous epidemics or pandemics [9,10], nurses presented the highest levels of occupational stress and distress compared to other personnel involved, indicating that they may have subsequently developed mental disorders. However, in the face of the negative consequences of stressors in clinical practice, there are nurses who demonstrate resilience after being exposed to a traumatic event and are successful in the face of the same challenges and limitations [11]. The American Psychological Association [12] defines resilience as the ability to adapt to adversity, trauma, tragedy, threats, or other significant sources of stress and, from this, seek a drive to cope and emerge successfully.
From the nursing discipline and perspective, this concept is related to Dorothy Johnson's Behavioral Systems Model, which focuses on how present or potential stress can affect a person's ability to adapt. For Johnson, the person is an interactive, interdependent, and integrated behavioral system with patterned, repetitive, and intentional forms of behavior [13,14]. The author reflects in her model that the human system is constantly subjected to stressors [14][15][16], which correspond to internal or external stimuli that produce tension and a certain degree of instability, giving rise to constructive or destructive behavioral changes, which can lead to equilibrium or imbalance. In view of this, the objective of the model is to maintain and recover equilibrium, helping the person to achieve an optimal level of functioning. This is why it is directly related to the term resilience [13], which is being increasingly researched within the field of nursing, since it is a capacity that is influenced by various factors and which allows the person to continue to project him/herself despite destabilizing events, both in patients and in the nursing staff itself. It has been shown that the most resilient nurses can better tolerate the hostile environment of pain, suffering, and death that they encounter throughout the workday [17], an environment that is especially aggressive during the pandemic.
Given the continuous exposure of nurses to human suffering and an adverse work environment, resilience has become so important that it is considered an inherent characteristic of nurses during the course of healthcare; there is evidence that resilience ameliorates the effects of work stress and largely avoids its long-term consequences [13]. Resilient nurses are seen as a crucial element in an ever-changing healthcare system [18], especially during the new SARS-CoV-2 pandemic situation.
In view of the above, it is relevant to explore care nurses' resilience in the face of the impact of the COVID-19 pandemic. Researching this could allow us to identify which aspects modulate its development, obtaining information on those nurses who prosper and continue to find satisfaction in their profession despite the current challenges and problems posed by this pandemic. This study aims to answer the research question: "Does resilience modulate the psychological impact on nurses of the COVID-19 pandemic?". Additionally, therefore, the aim of this study is to analyze the resilience of care nurses to the psychological impact of the COVID-19 pandemic.

Design
Systematic review was conducted between March 2020 and May 2021 according to PRISMA guidelines [19].

Protocol Development and PICO Question
The review protocol was developed to meet PRISMA [19], which was designed to answer PICO (Population, Intervention, Comparison, Outcome).
However, the stated focus question, "Does resilience modulate the psychological impact of nurses in the face of the COVID-19 pandemic?" was an adaptation of a PIO format question (Population, Intervention, Outcome) [20]: nurses (P), resilience (I), and psychological impact in the face of the COVID-19 pandemic (O).
The protocol for this review was not registered due to the rush to collect data in the midst of the pandemic and the desire to share our findings quickly.

Inclusion Criteria
We included studies published in Spanish or English; conducted (from March 2020 to May 2021) on nurses who cared for patients with COVID-19; investigating the influential factors of the psychological impact, resilience, strategies to develop it, or interventions to promote it during this pandemic and during others, such as SARS, MERS, or Ebola.

Exclusion Criteria
We excluded studies conducted on pediatric nurses, literature reviews, and papers that did not meet the necessary methodological quality.

Search Strategy
An exhaustive search was initiated in different databases. Electronic databases: Web of Science, Medline/Pubmed, Cochrane Collaboration (The Cochrane Library), BVS Biblioteca Virtual en Salud/LILACS, and CUIDEN. Subsequently, a manual review of the bibliographic references of the selected articles was carried out in order to include other potentially valid studies for the review. The keywords used concerned Medical Subject Headings (Mesh) [21]: nursing/nurses; coronavirus infections; resilience, psychological; adaptation, psychological; burnout, psychological; stress, psychological; uncertainty. In order to combine these terms, AND and OR were used as Boolean operators. Truncation operators were used as accuracy operators. Two researchers reviewed the selected and eliminated papers; if there were any discrepancies, a third reviewer intervened to decide their inclusion or exclusion.
The search strategy consisted of elaborating different search strings based on the above descriptors and free text (Table 1).

Study Variables
The variables in the review were: influential factors on the psychological impact of the COVID-19 pandemic, behavioral responses exhibited by nurses, level of nurses' resilience, influential factors on observed resilience, resilience-development strategies, and healthcare organization interventions to promote resilience in professionals.
Documentary quality assessment: Documentary quality was assessed through levels of evidence of effectiveness according to the Joana Briggs Institute (JBI) [22]; these are designed to align with the GRADE approach to pre-ranking findings based on the study design, which are then upgraded or downgraded depending on a number of factors.
Regarding the tool used to assess the methodological quality and the risk of bias of the articles, ICROMS [23] was used; it brings together different quality and methodological bias tools in a single document, allowing the quick and efficient selection and evaluation of different aspects and indicators of methodological quality. The tool consists of two parts: a list of quality criteria specific for each study design, as well as criteria applicable across all study designs by using a scoring system, and a "decision matrix", which specifies the robustness of the study by identifying minimum requirements according to the study type and the relevance of the study to the review question. The decision matrix directly determines inclusion or exclusion of a study in the review. ICROMS was used to analyze the quality and bias of the qualitative studies, whose minimum score was 16.
To assess the quality of systematic reviews, the AMSTAR-2 [24] tool was used, which was developed to evaluate systematic reviews. It allows a more detailed evaluation of the SRs that also include non-randomized studies of health interventions, which are increasingly incorporated in the SR. This questionnaire contains 16 domains with simple response options: "yes", when the result is positive; "no", when the standard was not met or there is insufficient information to answer; and "partial yes", in cases where there was partial adherence to the standard. Amstar-2 identifies the quality of reviews as high, moderate, low, or critically low quality.
Quality assessment of the cross-sectional studies in this review was performed using the STROBE [25] tool. The STROBE Statement is a list composed of 22 points that are considered essential for adequate communication of observational studies, allowing a critical evaluation of them. The cutoff score was 18/22.
An increase in tension and stress among nurses was detected compared to before the pandemic [33]. The most notable responses included fear, helplessness, discomfort with the scarcity and prolonged use of PPE, emotional distress, perception of providing poor nursing care [29,31,36,38,42,45], and concern and uncertainty for their safety and that of their families [29,36,38,40,42], even to the point of considering leaving the profession [36,38]. Physical symptoms related to the psychological burden were also detected [31,32,36,41].
An increase in tension and stress among nurses was detected compared to before the pandemic [33]. The most notable responses included fear, helplessness, discomfort with the scarcity and prolonged use of PPE, emotional distress, perception of providing poor nursing care [29,31,36,38,42,45], and concern and uncertainty for their safety and that of their families [29,36,38,40,42], even to the point of considering leaving the profession [36,38]. Physical symptoms related to the psychological burden were also detected [31,32,36,41].
Among the strategies developed by the nurses to favor their resilience and mitigate the psychological impact, the following prevailed: seeking socio-familial support [28,38,42,43], carrying out recreational and health-promoting activities [28,42,44], seeking information sources on psychological resources and clinical practice [29,42,43], and developing a positive and tenacious attitude [38,[42][43][44][45]. These strategies helped to stabilize the nurses emotionally and strengthen their resilience. The strategy they used the least was seeking professional psychological support [29,30,38,42].
Research indicated that nurses tended to adopt positive strategies in the face of the psychological impact of the COVID-19 [43] pandemic [28,29,38,42]. It was found that women were less likely to use coping strategies [28,29] and that nurses who suffered stress due to insufficient preparation and fear of contagion did not establish adequate strategies [29,33].
Concerning interventions to favor resilience and reduce the psychological impact of nurses in the face of this pandemic, the following were highlighted: offering training and clear instructions on the approach to patients with COVID-19, improving the working environment and working conditions, providing optimal protective material, promoting basic needs, and psychoemotional management [31,34,38,39,42,46,47]. Two articles classified interventions in terms of temporality, i.e., those to be carried out before exposure to the outbreak [42,46] (such as the provision of optimal education and training for the management of patients' psychological problems, diagnosis, and treatment; guidelines for infection prevention and control; resilience training to create a sense of preparedness for clinical practice); and during exposure [42,46] (such as providing personal protective equipment; favoring a good working environment; improving resilience through the adequate provision of information, psychosocial support, and treatment; monitoring the health status of professionals; and using various forms and contents of psychosocial support). Several barriers and guidelines were identified for the implementation of interventions to support nurses' resilience [44], such as the lack of awareness of practitioners' needs by organizations and limited resources, including a lack of materials, time, and staff skills.
The synthesis of the articles with the most relevant information from the retrieved documents can be seen in Table 2. The risk factors that had the greatest impact on the nurses were: direct contact with patients with COVID-19, doubt about the efficacy of PPE, younger age, and stigmatization. Working overtime and changing work routine was not a risk factor for the nurses in this study. Loneliness, sadness, fear, and concern for their family members were triggered as responses.
Faced with the stressors of the pandemic, nurses were more likely to develop positive strategies that were negatively related to psychological distress. Nurses who developed strategies such as overexertion in controlling coronavirus infection, avoidance, alcohol or drug use, and constructing false illusions were more likely to experience psychological distress.
The nurses in the study reported high levels of psychological resilience, which correlated positively with higher levels of perceived organizational support, leading to greater work engagement and quality of work. Resilience showed a mediating role between organizational support and nurses' work engagement.
Higher levels of resilience were also associated with having previously good emotional self-control and ability to adapt to challenges. The Chinese government issued a COVID-19 Disease Prevention and Control Plan, according to which Chinese hospitals were required to meet set standards and place special emphasis on developing organizational identity. Additional efforts were made to provide training and improve self-protection practices; protective measures were provided and evaluated, in turn improving nurses' resilience and work engagement. To investigate psychological abnormality in healthcare workers struggling with the COVID-19 epidemic and to explore associations between social support, resilience, and mental health.
Influencing factors in psychological impact and the psychological responses they can trigger in nurses.
Risk factors influencing worse mental health outcomes were: younger age and lower family and social support, observing the increasing number of COVID-19 cases and deaths, and not having experience in public health emergencies. They tended to develop psychological abnormalities in interpersonal sensitivity, emotional distress, hostility, and obsessivecompulsive behaviors in response.
The nurses in the sample presented moderate levels of resilience. Those who participated in previous epidemics had a significantly higher level of resilience compared to the others, which was associated with a better quality of the health interventions they provided. Perceived good social and organizational support, optimism, and tenacity were positively correlated with resilience and better mental health outcomes. To investigate the psychological impact and coping strategies of frontline medical personnel in Hunan province, adjacent to Hubei province, during the COVID- 19 outbreak between January and March 2020.
Stressors and protective factors of healthcare professionals and psychological effects generated by the impact of the COVID-19 pandemic.
The factors associated with stress were: younger age, shortage of PPE, working in front of patients on the frontline, and seeing news about the evolution of COVID-19. Longer shifts and overtime were not a stressor. The predominant responses induced were: loss of control, feeling of vulnerability, nervousness, hostility, tension, concern for their safety and that of their families, and intention to leave their post. The availability of strict infection control guidelines, specialized equipment, recognition of their efforts by the hospital administration and the government, and the reduction in cases reported by COVID-19 were assumed to be protective factors. The most commonly used strategies to reduce stress were applying strict protective measures, seeking help from family and friends, having a positive attitude towards oneself and one's work, and having a sense of humor. These strategies were mostly adopted by nurses compared to physicians and technicians. The least used strategy, in general, was to seek psychological support. Given the situation experienced by the nurses, in the survey, they expressed a number of interventions that could be made to promote their resilience and well-being: the availability of protective equipment, strict infection control guidelines, receiving specialized technical and emotional stress management training, and receiving support from hospital administration and government.   The most frequent stressors among the nurses were: lack of family support, work experience, time spent working in isolation rooms, prolonged use of PPE, and younger age. Among the responses triggered by this were: loneliness, guilt, fear of separation from their families, uncertainty, fear of infection, discomfort due to prolonged use of PPE, and concern about providing poor nursing care. The strategies adopted by the nurses to cope with stress were: acquiring training, seeking information on mental health, adopting a positive attitude, participating in health-promoting activities, and practicing relaxation techniques. The least used were those related to seeking professional psychological support. According to the nurses, the most effective main support interventions that could be adopted by the hospital to contribute to reducing stress and improving their resilience and well-being were: support from supervisors, provision of sufficient material, clear instruction on treatment procedures and on COVID-19, offering sufficient time off, professional promotion, and offering psychological services.  Among the most prominent interventions to foster resilience of health professionals in other outbreaks were: those related to working conditions (regular breaks, shorter working hours, team meetings, relaxation/recreation areas in workplaces, provision of epidemic training for professionals, training of professionals in helping patients and self); to support basic daily needs (food, rest); and those of psychological support (online, group therapies, etc.). A number of barriers were identified, such as lack of awareness of the needs of frontline workers by organizations and limited resources and guidelines, for the successful implementation of resilience-related interventions.  The nurses presented high levels of resilience, which were markedly higher than those obtained in other studies. Past experiences in public health emergencies and interventions developed by the hospital to foster organizational and social support, such as training of nurses to better manage the psychological problems of their patients and training on diagnostic guidelines and treatment of COVID-19 before entering the isolation ward. They were given priority access to PPE, a good working environment was fostered, flexible shifts were implemented according to work intensity, and a support team was established to protect the ward workforce. This notably influenced higher resilience scores in the nurses, considerably decreasing psychopathological symptoms, improving their sleep and eating quality, and leading to better mental health in nurses and quality results in their work. To analyze the cross-sectional effect of sources of stress during the peak of the COVID-19 pandemic on nurses' psychological distress, focusing on the mediating role of coping strategies, including problem-focused, emotion-focused, and resilience.
Stressors of nurses on the frontline of care for patients with COVID-19 and their response to those stressors.
Identified stressors: work overload, insufficient preparation to cope with work demands, and lack of support provoked fear of infection and death in nurses. Resilience is negatively and significantly related to psychological distress. Resilience can play an important role in improving mental health, but it will only reach higher levels and be a relevant mediator in the stressor-psychological distress relationship when the stressors have induced emotion-and problem-focused strategies. Individually, emotion-focused strategies combat psychological distress and are related to the development of resilience.
Problem-focused strategies alone are related to higher levels of psychological stress and distress in nurses. Nurses who experience stress due to insufficient preparation and fear of contagion do not implement adequate coping strategies and thus will not be able to acquire resilience. To explore how to develop and maintain the resilience of frontline healthcare professionals exposed to the working conditions of the COVID-19 outbreak.
Interventions before or during the outbreak to build nurse resilience.
Recommendations prior to the outbreak to promote resilience included: optimal provision of education, resilience training, and interventions to create a sense of preparedness for clinical practice. Recommendations during the outbreak consisted of: enhancing resilience through adequate provision of information, psychosocial support, and treatment; monitoring the health status of practitioners; and utilizing various forms and contents of psychosocial support.
AMSTAR-2 RATING Moderate JBI 4a-C Influencing factors in the psychological burden of nurses.
The relevant factors that were revealed as predictors of psychological burden in nurses were: being female, living with family members, being married, working in the emergency area or isolation room, not being trained for the integral management of the patient with COVID-19, and having a low economic level. The nurses perceived high hospital preparedness to correlate with moderate-high levels of resilience, decreasing the mean score of anxiety, stress, and depression. Factors such as age, experience, educational level, degree of trust in authorities, and perceived social and family support fostered resilience and reduced nurses' psychological burden. Hospital preparation, prevention, control, management, and containment of COVID-19, and government, social, and family support for nurses were relevant aspects that favored resilience.
Having a learning attitude, positive thinking, and acquiring updated training were resilience strategies for nurses to adapt psychologically in a more optimal way.

Discussion
This review was based on Dorothy Johnson's Behavioral Model [13][14][15][16]48] to broadly and holistically analyze the resilience of nurses in the face of the impact of the COVID-19 pandemic, which was a key competence to reducing or controlling the effects of the stress generated by this catastrophe. To this end, we explored the factors that influenced the psychological impact of the nurses, categorized by Johnson as internal stressing factors (ISF) and external stressing factors (ESF) [14], the behavioral and psychological responses in which they converged, as well as the determination of the nurses' resilience levels and the factors that influence it, classified as intrapersonal resilience factors (IRF) and environmental resilience factors (ERF), among other factors studied (Figure 2). health.

Discussion
This review was based on Dorothy Johnson's Behavioral Model [13][14][15][16]48] to broadly and holistically analyze the resilience of nurses in the face of the impact of the COVID-19 pandemic, which was a key competence to reducing or controlling the effects of the stress generated by this catastrophe. To this end, we explored the factors that influenced the psychological impact of the nurses, categorized by Johnson as internal stressing factors (ISF) and external stressing factors (ESF) [14], the behavioral and psychological responses in which they converged, as well as the determination of the nurses' resilience levels and the factors that influence it, classified as intrapersonal resilience factors (IRF) and environmental resilience factors (ERF), among other factors studied ( Figure 2). As in the current study, a high prevalence of stressors led to responses leading to psychological imbalance and distress in nurses in previous outbreaks, such as Ebola, H1N1, and SARS [49][50][51][52]. Evidence showed that female nurses had a significant risk of psychological distress, consistent with previous findings [49][50][51][52][53]. In this sense, nurses generally tend to be predominantly female, thus presenting higher additional workloads [54]. Being a nurse idiosyncratically implies having close contact with patients with COVID-19 and, therefore, a higher risk of becoming infected [33,38,39,43]; this aspect was identified as a key ESF for nurses in the context of this outbreak, as it has implications not only for their own health but also for that of their families [55].
It was detected that the preponderance of ESF has primarily induced dysfunctional psychological responses [33,36,38,39,42,43] in the affiliation, dependence, fulfillment, and aggression/protection subsystems, as well as dysfunctional physical responses [28,35,41,43] in the ingestion, elimination, and sexual subsystems, generating an imbalance in the nurses. This relates to Johnson's theory that a person's attempts to regain equilibrium in the face of a powerful force may require extraordinary energy consumption, even affecting biological processes [14]. These findings are in line with experiences in previous epidemics [52,56,57] and may indicate that mental disorders may develop in the long term.
The fundamentally low-moderate levels of resilience detected in nurses in the review [26,29,[33][34][35][36][37][38] were consistent with research conducted in other outbreaks, where concern was expressed about their low resilience [58][59][60][61]. Even resilient nurses were found to be stressed, albeit to a lesser degree. This fact is consistent with Jonhson's postulation that balance can also occur in illness [16]. Therefore, being resilient does not mean that nurses cannot experience feelings of emotional distress but rather that they have the skills to adapt to such a situation.
Nevertheless, the three studies that reported high levels of resilience [27,40,42] agreed that the aspects that marked this difference for other nurses were primarily related to ARF. This was in line with Johnson's approach, influenced by F. Nightingale, on the importance of approaching the person by focusing on his or her relationship with the environment, not with the disease [48]. The evidence was unanimous in indicating that the perception of social support was linked to less distress [29,[32][33][34][35]41], as this variable is an ERF known to be effective in reducing stress among nurses [13,62,63]. They especially valued social support from their families, a fact that is compatible with data from research on resilience. This may be the case because an individual's first social relationship is usually with his or her family. In the COVID-19 pandemic, this type of support was scarce [29,33,35,41], probably due to the isolating conditions caused by this virus, in addition to the fact that many were rejected by family and friends. Nurses not only had to deal with the COVID-19 pandemic but also with their concern for their families and the stigmatization of the public [31,41], so they had limited access to one of the key elements to foster their resilience, which in this study was a relevant ESF.
Because of this, organizational support from governments, hospitals, supervisors, and coworkers is especially important to fill this gap, being another ERF with an important positive influence on resilience [26,30,32,39,43]. Some studies state that higher levels of organizational support are significantly associated with effective work outcomes, fostering organizational identity, positive work attitudes, satisfaction, job commitment, and improved physical and mental health of nurses [62,64]. However, several articles in this review [26,29,[33][34][35][36]38] in which nurses had lower levels of resilience coincided with reporting a deficit of organizational support, making it a relevant ESF. Therefore, it was detected in this research that the fluctuation of resilience levels was significantly influenced by the presence of ERF.
The coping strategies developed by the nurses denoted a mediating role between resilience and stress. They were an effective tool to develop and reinforce IRF [27,28,30,31,37,41,43] and, at the same time, act primarily against EIFs since, due to the peculiarities of the transmission of this virus, the nurses had limited access to ARFs. Previous research has shown that problem-focused strategies are positively related to indicators of resilience, decreased stress, and psychological distress [65,66]; however, evidence from this study showed the opposite. This could occur because aspects such as the effort made to control the problems related to this virus, being permanently informed about it, and the fear of infection presented a relationship with greater stress, apart from the fact that they, in turn, were ISF detected in this review. Studies before the COVID-19 pandemic also concluded that emotion-focused strategies presented more inconsistent results in their relationship with nurses' well-being [66][67][68], but in this research, they presented a stronger connection with resilience. This could be because these types of strategies included, for example, adopting a positive attitude, performing relaxation techniques, or performing health-promoting activities [27,30,31,37,41,43], which were linked to a pragmatic way of embodying nurses' IRF.
Through this review, a group was revealed that requires special attention due to its greater vulnerability: nurses who are female, younger, and with less work experience [28,29,33] (three variables corresponding to ISF detected in this study). This could be related to the fact that many of this group are assigned jobs in special services or in areas of higher acuity/gravity. Additionally, some countries accelerated their final-year nursing students to join the nursing team earlier [69]. Mental health screenings would entail an approach that could help monitor both nurses' distress and the use of appropriate coping strategies. In fact, in this review, several studies [29,38,42] agreed that the strategy least used by nurses was seeking professional psychological support. We believe that this is due to the fear of being stigmatized for the use of this type of resource and reluctance to acknowledge the need for help.
Although relatively few studies investigated organizational interventions to promote nurses' resilience in the face of this pandemic, it is worth noting that the findings were extremely consistent, as the studies where higher levels of resilience were reported were those where organizational interventions were applied [27,40,42]. This lends confidence to the suggestion that implementing IRF and ERF through interventions are important targets for reducing the imbalance generated by both ISF and ESF and could even contain them and strengthen resilience. It may be too early to achieve published work in this area, but in other outbreaks or epidemics, common or similar barriers and facilitators were developed [44]; some research in other epidemics [70][71][72][73] suggests that providing education, training in resilience, providing psychological support, and providing the necessary resources are aspects that increase resilience and a sense of empowerment among nurses. This is consistent with previous experiences, in which it is reported that nurses repeatedly feel ignored by their managers when they raise concerns about their mental health [74].
Evidence from this study identified several barriers to the implementation of interventions by organizations, such as their lack of awareness of health workers' needs, along with resource constraints, including a lack of equipment, time, and staff skills. Organizational resilience [75] is defined as the ability of an organization to anticipate, prepare for, respond to, and adapt to incremental changes and sudden disruptions to survive and thrive, so this study shows that the impact of COVID-19 has been an additional assault on nurses' resilience, as nurses already had stressors in the healthcare environment before the pandemic [44,76]. The pandemic has also influenced the resilience of organizations, which was already impaired [75]. If organizations are weak, they will not be resilient and therefore will not be able to effectively develop interventions to develop competence in nurses, who in turn are part of these structures. Increasingly, evidence supports the close relationship between organizational resilience and outcomes [77], as nursing resilience must be approached as a collective and organizational responsibility, as it is not built alone, nor is it solely an individual responsibility.
Among the limitations found in this review, in addition to those of each of the papers reviewed (which, due to their design, do not generate a high level of evidence), it should be noted that in several cases, the interventions carried out by the organizations were communicated through brief comments, letters to the editor, editorials, or communications at congresses, probably driven by the urgent desire to share the findings during the period of the health crisis. By discarding these sources of information from the selection criteria, confidence that all relevant research was found is reduced.
The study results were collected in the most critical period of the pandemic, and therefore, some studies published later may not have been included in this review. Some psychosocially focused databases were not used, as a more clinical approach was intended; this may also have caused some articles to be missed. On the other hand, given that during the worst moments of the COVID-19 pandemic, scientific production was necessarily rapid and agile, it is logical that many cross-sectional observational articles were published, which we decided to include in the study despite the low evidence they provide. To evaluate them, we chose the STROBE tool, which, although it does not evaluate bias, is one of the tools used in Cochrane and is commonly used in published reviews, also of a systematic type.

Conclusions
Resilience has a key moderating role in mitigating the psychological impact of the COVID-19 pandemic on nurses in care, promoting their equilibrium, and promoting the quality of their work.
The COVID-19 pandemic has provoked massive exposure to stressors in nurses; external stressors are the main contributors to the responses generated, converging in those of psychological and physical etiology.
The levels of resilience of nurses in the face of this health crisis are predominantly low-moderate, whose fluctuation is due to the interaction between intrapersonal and especially environmental factors, along with the presence of stressors.
The strategies developed by nurses to cope with the psychological impact are useful to promote IRFs, partially promote ARFs, and combat SIFs. Identifying when nurses may possess factors that expose them to developing negative coping strategies, ineffective coping, and finding ways to foster more positive approaches to managing stress will be key to nurses ultimately achieving optimal levels of resilience while avoiding imbalances and the risks of adverse health consequences.
Interventions developed by healthcare organizations play the most relevant role in fostering nurses' resilience in the face of this pandemic, as it is through them that this skill can be holistically and comprehensively trained and promoted.