Introduction

Countries in Europe as well as the United States are in the process of widely adopting a pioneering approach to interdisciplinary collaboration wherein specialists in multiple fields work together with a common goal centered on the patient/family (Reeves et al., 2017). Under this approach, interdisciplinary members work together in a horizontal relationship, in which all positions are presumed to share common knowledge, skills, and values (Tamura, 2018). Whereas the primary aim of interdisciplinary collaboration in most countries is to improve the quality of medical care, in Japan, the primary aims include reducing physician burden (Tsuruta, 2019) and transferring skills from physicians to nurses or other healthcare professionals (Tamura, 2018). In other words, interdisciplinary collaboration in Japan is largely a complement to job sharing.

In intensive care units (ICUs), interdisciplinary collaboration is vital to providing safe and effective care to patients (Aghamohammadi et al., 2019; Reader et al., 2009), and physician–nurse collaboration is associated with improved long-term patient outcomes (Baggs et al., 1999). However, nurses struggle in the decision-making process of patient care in the ICU (Coombs & Ersser, 2004), and lack of collaboration is a contributing factor for both burnout and turnover (Sundin-Huard, 2001). In recent reports, lack of cooperation has been found to be a factor in burnout for not only nurses but also ICU physicians (See et al., 2018; Welp et al., 2019). Hence, interdisciplinary collaboration is an important issue not only for patient care quality but also for ICU healthcare professionals.

In Japan, medical policies include the enhancement of interdisciplinary collaboration. Leadership is necessary to provide interdisciplinary collaboration and quality care, and good leadership has been shown to improve healthcare provider satisfaction (Kiwanuka et al., 2021). One of the effects of ICU leadership is improving the ability to make appropriate decisions (Brewster et al., 2020). This underscores the importance of leadership in bringing patients, families, and healthcare providers together to make decisions about patient care (Kiwanuka et al., 2021).

Currently, most ICU interdisciplinary collaboration leaders are physicians. However, hospital management systems require that physicians also work outside the ICU, making healthcare professionals other than physicians necessary to achieve effective interdisciplinary collaboration. The process of integrating interdisciplinary collaborations is complex, and historical hierarchical factors and boundaries must be overcome (Goldsberry, 2018). In fact, there are differences in perceptions of interdisciplinary collaboration in ICUs among different healthcare providers, and nurses and clinical engineers tend to be less satisfied with collaboration than physicians (Yamamoto, 2020). Nurses should develop leadership abilities to make autonomous decisions and take actions to better care for patients and their families.

The movement to promote team-based medical care has grown over the years, with its principles already woven into the essence of becoming a nurse (Ujike, 2016). Critical care nurses require a high level of practice to understand the complex medical conditions of their patients and to provide pain relief and promote physical functional recovery effectively. Nurses are the healthcare professionals who spend the most time with patients and their families and are thus in a good position to understand patient needs at an early stage (Lakanmaa et al., 2015). For example, ICU nurse leaders collaborate with various disciplines, including nursing, to meet the needs of patients and their families (Milner et al., 2020). In addition, they promote the release of physical restraints through appropriate assessments of patients under restraint (Kirk et al., 2015).

Practical ability in nurses requires leadership, the ability to exercise membership, and the ability to coordinate (Bender, 2016). Nurses work in a timely manner to provide the care necessary to meet the needs of patients and their families (Sakata & Murata, 2017).

Considering that each professional has been trained to provide effective team care with positive interpersonal interactivity, nurses are well qualified to lead teams (A. B. Hamric & Blackhall, 2007; Mayo et al., 2017). Leading the team also benefits the health professional as a whole (Cooper et al., 2019) to promote collaboration within the healthcare team with skilled practitioners and leaders as “bridging.”

According to Urisman et al. (2018), nurse participation in interdisciplinary rounds in the surgical ICU improves communication and collaboration among practitioners. Moreover, leadership is important for safe treatment in ICU incident rates (Pronovost et al., 2006). In other words, nurses should exercise leadership to improve patient and family care and coordinate with various healthcare providers for the smooth provision of medical care.

Having the coordination skills necessary to build excellent communication and relationships is critical to the development of leadership abilities (Tracy & O'Grady, 2019). This practice will promote interdisciplinary collaboration. However, the role of ICU nurses in interdisciplinary collaboration and leadership in patient care remains unclear. It is considered that clarifying this will help elucidate the impact of nurses on interdisciplinary collaboration and lead to the development of nurses who are better prepared to promote interdisciplinary collaboration.

This study was designed to determine the relationship between leadership ability in critical care nurses and interdisciplinary collaboration.

Methods Definition of Terms

Nursing leadership is defined as follows: Nurses should take the initiative to influence relevant healthcare providers, patients, and patient families to provide patient-centered care. In addition, as patient advocates with the aim of providing patient-centered care, nurses influence the patients, patient families, and healthcare providers. This is required of all nurses who practice care.

Coordination is defined as smoothly providing necessary care to patients and their families by conducting activities that facilitate interdisciplinary and patient–family relationships.

Research Design and Participants

The design of this study was cross-sectional. The survey questionnaire used to collect data targeted 400 institutions with a certified ICU (as of April 2016) in Japan. This survey was conducted by mail, and the number of facilities targeted was determined based on the assumption of a 30% response rate. The institutes were asked by letter to participate in the research, with 168 agreeing to participate.

A total of 3,324 nurses, including certified nurses (CNs), certified nurse specialists (CNSs), nurse practitioners (NPs), and nurse managers, who had worked in their respective ICUs for at least 3 years were enrolled as participants. In Japan, CNS and CN qualifications may be obtained after completing a master's degree at least 5 years after obtaining a nursing license. CN is a qualification that a nurse who has been qualified as a nurse for ≥ 5 years may obtain after receiving 6 months of professional education. In this study, CN, CNS, and NP are identified collectively as advanced practice nurses (APNs). Three years or more of clinical experience was specified in this study based on Benner's (1999) “The Five Dreyfus Model Stages” statement that quality of care is ensured by grasping the whole experience and working with the medical team.

The Investigation Nursing leadership ability (primary outcomes)

Leadership ability was defined based on the perspective presented in Oba (2009). With permission, we used a leadership practice index (Self-Assessment Inventory of Leadership role for staff nurses, SAIL; Cronbach's α = .90; Oba, 2009) for data collection. This scale was developed based on the idea that leadership, which includes nurses' influence on others, is necessary to providing patient-centered care. SAIL addresses five factors and consists of 20 items scored on a 5-point Likert scale ranging from 1 (not at all or not) to 5 (always present or sufficient). Scores for the five subscales and the entire scale (20–100 points) were calculated, with higher scores associated with better nursing leadership ability. The five SAIL subscales include (a) sharing of a common goal with patients (Are patient intervention goals set equally well by the patient and nurse?), (b) self-realization of the importance of relationship building with the patient (Is the interaction between the patient and the nurse centered on the patient?), (c) providing flexible care services (Does the financial instruments' business operator provide flexible and appropriate assistance in accordance with the situation?), (d) interdisciplinary collaboration (What is the quality of response by healthcare providers during delivery of care?), and (e) sense of professionalism and willingness to provide the best possible care (question the identity and ethics of nurses). Furthermore, collaboration with multiple healthcare providers includes receiving expert advice from other disciplines, discussing the role of nurses with other healthcare providers during care, and asking other healthcare providers to cooperate with the care plan.

Perception of interdisciplinary collaboration (secondary outcomes)

The items related to the actual state of interdisciplinary collaboration were the presence of interdisciplinary conferences, opportunities to discuss at conferences, interdisciplinary joint study meetings, consultation opportunities and protocols for medical teams, and authority transfer. In addition, the degree of leadership and coordination among team members for collaboration in the ICU, the degree of difficulty in collaboration, and the degree of collaboration among different professions were measured using a visual analog scale (1–100). To be recognized as team members, the participants were required to answer affirmatively to two questions and to freely describe their conscious acts as promoting interdisciplinary collaboration. Next, the education, experience of interprofessional education, existence of professional qualification, ICU management system, and basic attributes of the participants were investigated. The ICU management system is divided broadly into four categories: first, an intensivist (physician with a specialty in intensive care) who has full responsibility for patient care (closed ICU); second, the management system (work with the patient's primary physician) in which the ICU intensivists are involved in all treatment decisions for patients admitted to the ICU (mandatory critical care consultation; semi ICU-M); third, a management system that involves intensivists only when consulted by the patient's primary physician (electric critical care consultation; semi ICU-E); and fourth, a management system in which there is no intensivist in the ICU and the patient's primary physician is responsible for treatment (open ICU).

Moreover, the level of interdisciplinary collaboration across the ICU to which each participant belonged was determined using the Collaboration and Satisfaction About Care Decisions (CSACD) questionnaire (Baggs, 1994). The reliability of this scale was previously confirmed (Cronbach's α = .95), and it was reverse-translated into Japanese and used with the permission of the developer. The content validity of the Japanese version was confirmed using confirmatory factor analysis (adjusted goodness of fit index = .88, goodness of fit index = .94, comparative fit index = .96, root mean square error of approximation = .05), and the Cronbach's α was .94. The CSACD consists of seven items related to collaboration (range: 7–49 points) and two items related to satisfaction with collaboration (range: 2–14 points). This questionnaire is scored using a 7-point Likert scale, with higher scores associated with higher degrees of multidisciplinary collaboration in the ICU. Finally, the conscious acts of nurses related to interdisciplinary collaboration were investigated based on their free-form description.

Data Collection

A survey request form describing the purpose of this study, an anonymous self-administered questionnaire, and a return envelope were sent to ICU nurses at the 168 institutions that had cooperated in the survey in advance. The nurses confirmed the purpose and method of the survey in writing, and those who agreed to participate filled out the questionnaire and then returned it by mail. The survey period was from April to September 2016.

Data Analysis

Descriptive statistics were calculated for each question item. After checking the description normality, we calculated the estimation statistics. Next, using SAIL as the dependent variable and the others as the independent variables, we compared the items or independent variables using a t test or one-way analysis of variance. When a difference fell below the 5% significance threshold, we conducted a Tukey's multiple comparison test. When no equal group variance could be assumed, Welch's test was used. When the significant difference was less than 5%, we used the Games–Howell's multiple comparison method. The causal relationship of SAIL was examined using multiple regression analysis (forced input method). All of the statistical data were analyzed using the statistical analysis software SPSS Statistics Version 25 (IBM Inc., Armonk, NY, USA) and AMOS 4.0 (IBM Japan Ltd.) with the supervision of a statistics expert. A p value of < 5% was considered statistically significant, and the data were expressed as mean ± SD.

The contents of the free-form description were analyzed using a text mining software program (IBM SPSS Text Analytics for Surveys [TAFS] 4.0). For the primary analysis, keywords were analyzed, and synonyms and unnecessary words in the extracted keywords (following the concept) were arranged. Next, modification analysis was performed. After the concept was extracted, the category was created using a linguistic method, followed by confirmation and manual correction. After calculating the basic statistics, we estimated the other items to be related to the categories derived by TAFS (binary data), and the significance was analyzed using a χ2 test.

Ethical Considerations

The investigator's ethics review committee approved this study (approval number: 27-337: 8222). As explained in writing, participation in this study was wholly voluntary, and each participant provided informed consent. The questionnaire was filled out and submitted anonymously.

Results Participant Demographics

Participant characteristics are summarized in Table 1. The 2,062 valid responses gave a valid response rate of 62.0%. Of these, 696 (33.8%) responded that they were writing free-form description/opinion. The ICU management system provided the characteristic data for the participants. The largest number of participants were from open ICU (827 [40.1%]), followed by semi ICU-M (622 [30.2%]), semi ICU-E (458 [22.2%]), and closed ICU (155 [7.5%]). Furthermore, 124 (6.0%) were APNs (i.e., CNs, CNSs, or NPs).

Table 1. - Participant Characteristics (N = 2,062) ICU Management System, n (%) Characteristic Total n (%)
(N = 2,062) Closed ICU
(n = 155) Semi ICU-M
(n = 622) Semi ICU-E
(n = 458) Open ICU
(n = 827) Age (years; M and SD) 34.3 7.1 34.6 7.0 34.1 7.2 35.2 7.5 34.3 7.5 Clinical experience (years; M and SD) 12.4 7.2 12.7 6.8 12.1 6.9 12.9 7.1 12.4 7.2 Female 1,707 82.8 133 85.8 524 84.2 386 84.3 664 80.3 Education  High school or associate degree 1,553 75.3 115 74.2 444 71.4 342 74.7 652 78.8  Undergraduate 469 22.7 36 23.2 164 26.3 107 23.3 162 19.6  Master's or doctorate degree 40 1.9 4 2.6 14 2.3 9 2.0 13 1.6 Interprofessional education 280 13.6 18 11.6 88 14.1 69 15.1 105 12.7 Position  Head nurse 151 7.3 17 11.0 43 6.9 31 6.8 60 7.3  Deputy manager 218 10.6 24 15.5 64 10.3 51 11.1 79 9.6  No position 1,693 82.1 114 73.5 515 82.8 376 82.1 688 83.2 Degree of overtime (M and SD) 3.1 1.0 3.2 1.1 3.0 1.0 3.1 1.0 3.0 1.0 Degree of staffing sufficiency (M and SD) 2.8 1.1 2.7 1.1 2.8 1.0 2.8 1.1 2.8 1.2 Number of ICU beds (M and SD) 9.5 4.8 11.1 5.0 10.3 5.4 9.3 7.7 8.7 4.1 APNs in ICU 1,715 83.2 132 85.2 552 88.7 375 81.9 656 79.3 APNs 124 6.0 10 6.5 33 5.3 29 6.3 52 6.3

Note. ICU = intensive care unit; APNs = advanced practice nurses; Semi ICU-M = the intensivist is not the patient's primary attending physician, but every patient admitted to the ICU receives a critical care consultation (mandatory critical care consultation); Semi ICU-E = the intensivist is involved in the care of the patient only when the attending physician requests a consultation (electric critical care consultation).

Nursing Leadership Abilities

The Cronbach's α coefficients for the SAIL subscales I, II, III, IV, and V in this study were .83, .81, .83, .76, and .89, respectively, and was .90 for the SAIL total score. Qualified nurses scored significantly higher on all items than nonqualified nurses (p < .001) and nurses in higher position (p < .001). Conversely, no significant differences were found in the presence of APN in the institutions (p = .321) or in the ICU management system (p = .116; Table 2).

Table 2. - Self-Assessment Inventory of Leadership Role for Staff Nurses Score (SAIL Score; N = 2,063) Factor SAIL a p I II III IV V Total Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Total score 20.3 3.6 15.6 2.1 14.9 82.3 10.2 2.2 10.8 2.3 71.8 9.5 ICU management system b .116 c  Closed ICU 20.7 3.8 15.8 2.1 15.2 2.4 10.5 2.3 11.0 2.5 73.1 9.7  Semi ICU-M 20.2 3.6 15.6 2.1 14.9 2.3 10.2 2.1 10.6 2.4 71.5 9.4  Semi ICU-E 20.5 3.5 15.7 2.1 14.9 2.3 10.2 2.1 11.0 2.3 72.3 9.1  Open ICU 20.2 3.7 15.5 2.1 14.8 2.3 10.1 2.3 10.8 2.3 71.5 9.7 Professional qualification < .001 d  APNs 22.3 3.7 16.7 2.1 16.5 2.0 10.9 2.1 12.4 2.1 78.8 9.5  Not APNs 20.2 3.6 15.5 2.1 14.8 2.3 10.1 2.2 10.7 2.3 71.3 9.3 APNs in ICU .321 d  Yes 20.4 3.6 15.6 2.0 14.9 2.3 10.2 2.2 10.8 2.3 71.9 9.4  No 19.8 3.9 15.6 2.1 15.0 2.4 9.9 2.3 10.9 2.4 71.3 9.7 Position < .001 d  Head nurse or deputy manager 20.8 6.5 16.1 2.2 15.7 2.2 10.7 2.0 11.8 1.8 74.9 8.9  No position 20.2 6.9 15.5 8.2 14.7 2.3 10.1 2.2 10.6 2.4 71.2 9.4

Note. SAIL = Self-Assessment Inventory of Leadership role for staff nurses; ICU = intensive care unit; APN = advanced practice nurse.

a SAIL subscales: I, the sharing of a common goal with patients; II, self-realization of the importance of relationship building with the patient; III, providing flexible care services; IV, interdisciplinary collaboration; V, sense of professionalism and willingness to provide the best possible care. b ICU management system: Semi ICU-M, intensivist intervening for all patients admitted to the ICU was designated as mandatory critical care consultation; Semi ICU-E, the facility where the intensivist intervenes was designated as electric critical care consultation. c One-way analysis of variance. d Student t test.

Perception of Interdisciplinary Collaboration

The results of participant perceptions of interdisciplinary collaboration are summarized in Table 3. In the ICU, 1,591 (77.2%) had attended interdisciplinary conferences, 1,239 (60.1%) had joined interdisciplinary joint study sessions, and 1,626 (78.9%) had related protocols. For the question “Who do you recognize as team members?” less than 50% of the respondents chose patients and their families. Moreover, regarding collaboration with multiple healthcare providers in the ICU, nurse–nurse collaboration was the highest (mean ± SD = 81.5 ± 17.8), followed by physician–nurse collaboration (65.9 ± 22.9). The degree of difficulty in interdisciplinary collaboration in the ICU was 50.9 ± 26.0, and the extent to which nurses coordinated collaboration among team members was 45.2 ± 30.6.

Table 3. - Factors Related to Collaboration Factor ICU Management System Total (N = 2,062) Closed ICU
(n = 155) Semi ICU-M
(n = 622) Semi ICU-E
(n = 458) Open ICU
(n = 827) M SD M SD M SD M SD M SD Holding multidisciplinary conferences (n and %) 1,591 77.2 131 84.5 537 86.3 339 74.0 584 70.6 Conference attendance 3.2 1.3 3.3 1.3 3.3 1.4