Conceptual and operational definitions of the components of the nursing diagnosis Acute Pain (00132)

ABSTRACT Objective: to develop the operational and conceptual definitions of the defining characteristics and related factors of the nursing diagnosis Acute Pain (00132) for nonverbal critically ill patients. Method: integrative literature review in the databases/libraries: Medical Literature Analysis and Retrieval System Online (MEDLINE via Pubmed), Cochrane Library, The Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Latin American & Caribbean Health Sciences Literature (LILACS). Results: 799 results were found in the literature, of which 80 studies were selected for full text reading and 16 were used in the elaboration of definitions for the 17 defining characteristics and three related factors of the nursing diagnosis. The gray literature, ie, thesis, dissertations, books, guidelines and dictionary was also explored to ensure the robustness needed to clarify the topics not covered by the studies. Conclusion: the definitions aim to facilitate the identification of the nursing diagnosis for nonverbal critically ill patients and to support future teaching and research on the nursing diagnosis of Acute Pain (00132).


Introduction
Pain is defined as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage" (1) , and it can be influenced by multiple factors. It is the most common subjective condition to lead people to see a health professional (2).
In the intensive care unit (ICU), pain is a consequence of therapeutic and diagnostic procedures, an inadequate pain relief can have deleterious effects on patients, such as altered respiratory mechanics, increased cardiac demand, muscle spasms, contractions and even muscle rigidity (3) .
On the other hand, pain can be difficult to assess in critically ill patients, delaying their treatment. A study conducted through post-discharge interviews with ICU patients found that 63% had had moderate to severe pain during their stay in the ICU and had difficulties to communicate their pain to the health team (4) .
Verbal communication is gold-standard for assessing pain. However, the inability to communicate verbally, present in many patients in intensive care units, does not negate the possibility that they are experiencing pain and need to have treatment (1) .
Due to this problem, statistics for pain prevalence are practically non-existent for nonverbal patients and patients suffering from severe illnesses or with cognitive impairment are often excluded from pain prevalence studies (5) . However, a large study called Thunder II (3) listed procedures that can cause pain. In adults, the procedures with higher levels of pain were turning in bed, drain removal, wound care, tracheal suctioning with a lower score, and central catheter placement. These are common procedures, constantly performed in ICUs.
Therefore, it is fundamental to study, identify and control pain in this environment.
In their daily practice, ICU nurses must have quick decision-making skills based on the observation of physiological and behavioral changes in patients. The direction of the nursing care depends on the nurses' rapid observation, since complications that affect the recovery of their patients can be prevented (2) . This rapid assessment is expressed through the identification of the nursing diagnosis (ND). For this, nursing professionals can rely on their own taxonomies, such as the NANDA International classification (NANDA-I) (6) , which provides standardized terms and helps making the best choice of interventions to achieve favorable nursing outcomes, always taking the nurses' clinical judgment into account (7) . In order to make an ND, the nurse needs to assess the signs and symptoms presented by the patient, which are called defining characteristics (DC), and identify the contributing factors that led to that ND, called related factors (RF). Studying all these elements is essential, revising and evaluating their application in different populations and addressing as many indicators and terms as possible in order to determine accuracy and support their use in diverse populations.
These studies aim to improve the DCs commonly identified for the NDs (8) . Currently, these studies proposed by nurses have sought to study these DCs in specific populations. Therefore, NDs are based on evidence that can be generalized (8) and used by nursing professionals.
These validation studies provide refinement and improvement of classifications, which favors the exercise of critical thinking and decision-making and improves communication and standardized nursing records (7) . Therefore, the objective of this study is to develop conceptual and operational definitions of each DC and conceptual definitions of the related factors present in NANDA-I (6) for the ND Acute Pain (00132). The development of the definitions aims to support nurses in the identification of these characteristics in the population and represents the initial phase of the validation study.

Method
The methodological process of this integrative review was in agreement with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes -PRISMA (9) . This process consisted of the following steps: identification of the problem; literature search; evaluation and selection; analysis and presentation of data (10) .
The selected studies were thoroughly read and data were extracted using an instrument validated in Brazil (11) , which included the identification of the study, setting of the study, the characteristics of the journal, the methodological characteristics and an assessment of methodological rigor. After data extraction, an information table was constructed with data from the studies: authors, title, journal, country, language, year of publication, objective, design, population, result and level of evidence. The level of evidence was classified in seven levels (12) : level I, evidence from a systematic review or meta-analysis of all relevant randomized controlled trials or from guidelines based on systematic reviews of randomized controlled trials; level II, evidence obtained from at least one well-designed randomized controlled www.eerp.usp.br/rlae 3 Correia MDL, Duran ECM. trial; level III, evidence from well-designed controlled trials without randomization; level IV, evidence from cohort or case-control studies; level V, evidence from systematic reviews of descriptive and qualitative studies; level VI, evidence from a single descriptive or qualitative study; level VII, evidence from the opinion of authorities and/ or reports of expert committees. Thus, a dictionary (13) , two dissertations (14)(15) , a thesis (16) , two books (17)(18) and a guideline (19) were included, totaling 23 items that supported the development of conceptual

Results
The studies selected supported the development of this study. None of them had level of evidence I or II, due to the characteristics of the subject; however, they provided valuable contributions that supported the development of the definitions.

Title Country Year Objective
Vital signs are not associated with selfreported acute pain intensity in the Emergency Department (20) Canada 2016 To determine the association between self-reported pain intensity and vital signs Emergence delirium or pain after anaesthesia--how to distinguish between the two in young children: a retrospective analysis of observational studies (21) Italy 2016 To identify individual observational variables of the domains commonly used in the PAED, FLACC, CHIPP and CHEOPS scales, which can distinguish delirium from pain.

Experiences of individuals with suicidal ideation and attempts (22) Colombia 2016
To explore the experiences of people who have attempted suicide Understanding Pain and Depression in Back Pain: the Role of Catastrophizing, Help-/Hopelessness, and Thought Suppression as Potential Mediators (23) Germany 2016 To examine the influence of catastrophizing, help-/hopelessness and thought suppression as potential mediators in the relation between pain and depression Diagnósticos de enfermagem identificados em pacientes onco-hematólogicos: mapeamento cruzado (24) Brazil 2015 To compare free terms from nursing records with a standard nursing diagnosis classification.
Pain Assessment: validation of the physiologic indicators in the ventilated adult patient (25) China 2015 To validate the discriminant and criterion validity of physiologic indicators for pain assessment in nonverbal patients Pain assessment using self-reported, nursereported, and observational pain assessment tools among older individuals with cognitive impairment (26) Malaysia 2015 To compare self-reported pain, nurse-reported pain and an observational pain tool to assess the performance and accuracy of these tools among older patients with cognitive impairment. Pain-related evaluation and interventions in children in the anesthetic care unit (28) Brazil 2013 To assess pain, changes in vital parameters and prescription of analgesics to preschoolers in the immediate postoperative period of general surgery, during their stay in the post-anesthetic care unit.
Clinical validation of the nursing diagnosis labor pain (29) Brazil 2013 To verify the frequency of the DCs of the ND "labor pain" among parturients in the active phase of labor.
Acceptance, cognitive restructuring, and distraction as coping strategies for acute pain (30) Germany 2013 To explore the effects of acceptance, distraction and cognitive restructuring on pain tolerance and intensity.
Behavioral pain indicators in people with intellectual disabilities: a systematic review (31) The Netherlands 2013 To identify behavioral pain indicators in people with intellectual disabilities.
Postoperative pain and analgesia: analysis of medical charts records (32) Brazil 2013 To analyze records of postoperative pain and analgesia on patients' medical charts.
Patterns and clinical correlates of pain among brain injury patients in critical care assessed with the Critical Care Pain Observation Tool (33) South Korea 2013 To assess the patterns and clinical correlates of acute pain in brain injury patients during the critical care period using the CPOT.
Description of behaviors in nonverbal critically ill patients with a traumatic brain injury when exposed to common procedures in the intensive care unit: a pilot study (34) Canada 2013 To explore pain-related behaviors of TBI patients when exposed to a painful procedure (turning), compared to rest and noninvasive blood pressure monitoring in the ICU.

and the McGill Pain
Questionnaire (29) . Some specific instruments were also used to assess pain in the articles selected: the PAINAD (Pain Assessment in Advanced Dementia) (26) was used for patients with dementia, the FLACC (Faces, Legs, Activity, Cry, and Consolability) (21) , the CHIPP (Children's and Infants' Postoperative Pain) (21) and the CHEOP (Children's Hospital of Eastern Ontario Pain) (21) for children and PBAT (Pain Behavior Assessment Tool) (34) and CPOT (Critical-Care Pain Observation Tool) (27,34) , both observational tools, were used for patients who couldn't communicate.
Regarding the method, there were descriptive and qualitative studies, systematic reviews of the literature and of patient records, observational studies and controlled studies without randomization.
The operational and conceptual definitions of the  (20) in which the person in pain (14) makes a verbal report (13) characterizing pain intensity (32) , that is, the person evaluates and quantifies their level of pain; Operational definition: Verbal report of conscious and minimally verbal person (33) , requested to quantify their pain using standardized scales appropriate for their age group/ clinical condition and translated and validated in Brazil.

Self-report of pain characteristics using standardized pain instrument (e.g., McGill Pain Questionnaire, Brief
Pain Inventory) -Conceptual definition: It is a subjective evaluation (20) in which the person in pain (14) makes a verbal report (13) characterizing aspects of their pain other than intensity: location (32) , quality (18,28,30,(32)(33) , duration (28) , improvement and worsening factors (32) , factors associated (32) , affective influence (28) ; Operational definition: Verbal report of conscious and minimally verbal person (33) , requested to evaluate their pain regarding location, quality, duration, improvement and worsening factors and affective influence, using standardized scales appropriate for their age group/clinical condition and translated and validated in Brazil.

Distraction Behavior -Conceptual definition: It is
the lack of concentration in the surroundings (13) ; little attention to environmental stimuli (30) ; lack of attention (14) .
It is an adaptation behavior (30) to a painful event, through which the person remains distracted and away from the real world; Operational definition: Identified through concentrated observation (18) to recognize the individual oblivious to the environment.
Protective Behavior -Conceptual definition: Reaction to external aggression (physical examination, procedures) in an attempt to protect or defend (13) the area of the body affected by pain; Operational definition: Identified through concentrated observation (18) to spot the individual flinching the region of the body affected by the pain when it receives stimuli (touch, compression, physical contact).
Hopelessness -Conceptual definition: It's an emotion (23) related to lack of hope (13) , of trust in something positive (13) and of meaning of life (24) . It is a negative subjective and discourse analyses) (18) to recognize negative verbal reports about the future regarding the pain. E.g.: "This pain will never go away", "This pain will kill me".
Diaphoresis -Conceptual definition: It is the secretion of sweat (13) and perspiration in abundance (16,35) , as an answer from the autonomic nervous system to the stress (35) caused by pain; Operational definition: Identified through inspection (18) of evident perspiration on the face, hands, armpits and skin folds (18) . It can be confirmed by using a paper towel on the visually affected site (16) .
Self-focused -Conceptual definition: Focus is the point to which something converges (13) . Self-focus is a strategy to conserve energy; the individual on pain tries to protect himself, saving energy to go through the period of suffering. This is done through immersion in oneself and self-centering, to concentrate all vital force to cope with the moment of pain; Operational definition: Identified through observation (18) to recognize an individual who is not very communicative, and may have closed eyes and little contact with others.
Narrowed focus -Conceptual definition: Focus is the point to which something converges (13) . An individual with narrowed focus uses it as a self-protection mechanism, preventing that other people or the environment bring more suffering than the pain already endured. This resource is a defense mechanism against external aggressions that could delay recovery or increase suffering; Operational definition: Identified through observation (18)  Protective Behavior -Conceptual definition: Voluntary or involuntary body movement (13) revealing an intention to relieve pain of a certain area of the body; Operational definition: Identified through concentrated observation (18) to perceive the individual touching, holding or compressing a body part affected by pain.

Appetite change -Conceptual definition: Change
in the desire to eat (13) (increase, decrease or absence of habitual food intake), regardless of the type of food offered (14) , initiated with (and because of) the occurrence of painful event (14) ; Operational definition: Identified through the verbal report of changes in food intake and/ or observation of the food intake pattern (16) .
Change in physiological parameter (e.g., blood pressure, heart rate, respiratory rate, oxygen saturation, and end-tidal CO 2 ) -Conceptual definition: Changes in vital signs caused by the release of catecholamines (25) as a response to painful stimuli: *increase in blood pressure: blood pressure is the force of blood against the side walls of blood vessels. Systolic blood pressure (SBP) is the maximum pressure perceived during contraction of the left ventricle or systole. The diastolic blood pressure (DBP) corresponds to a period of rest between each contraction.
The mean arterial pressure (MAP) is the pressure that forces the blood towards the tissues and it corresponds to the mean of the entire cardiac cycle. This is an arithmetic mean between systolic and diastolic pressures, since diastole lasts longer (18) . Reference values: SBP greater than or equal to 140mmHg and/or DBP greater than or equal to 90mmHg (19) ; MAP between 70 and 105 mmHg (17) ; *increase in heart rate: number of heart beats in one minute. In the normal adult it varies from 60 to 100 beats www.eerp.usp.br/rlae 7 Correia MDL, Duran ECM.
per minute (18) ; *increase in respiratory rate: number of respiratory cycles in one minute. In normal adults it varies from 10 to 20 breathes per minute (18)  Positioning to ease pain -Conceptual definition: Unusual body posture (15) adopted by the individual in an attempt to avoid or minimize pain (14) ; Operational definition: Identified through concentrated observation (18) of the posture adopted, looking for fetal position, child's pose or other postures (15) .
Proxy report of pain behavior/activity change (e.g., family member, caregiver) -Conceptual definition: Exposition, description or narration (13) of a caregiver, family member or member from the health team familiar with the behavior of the person, about a change in their behavior (26) that Physical injury agent (e.g., abscess, amputation, burn, cut, heavy lifting, operative procedure, trauma, overtraining) -Conceptual definition: Something that causes an injury (pathological or traumatic tissue damage) (13) related to a physical event of an accidental or surgical damage on organic tissues.

Discussion
The symptom of pain is a pressing issue among hospitalized patients, since millions of people suffer from pain as a result of trauma, surgery or diseases (36) (37)(38)(39) , which makes this study even more important.
Moreover, since the conceptual and operational definitions clarify and reinforce the items in an ND, this study contributes to the development of specific language, which allows for future discussions on the best available evidence on these components and their applicability to specific populations.
Validation studies provide refinement and improvement of classifications, which favors the exercise of critical thinking and decision-making and improves communication and standardized nursing records (7) .
The use of standardized language favors universality and dissemination of information. Therefore, it also benefits teaching activities, since students can better understand the phenomenon studied.
The present study aimed to elaborate the conceptual and operational definitions of the DCs and the conceptual definitions of the RFs of the ND Acute Pain (00132), addressing nonverbal patients in the ICU. The importance of describing this phenomenon is evident, since it can provide the scientific support for nurses to identify an ND that represents, in fact, the patient's response (40) .
In addition, the knowledge about the conceptual and operational definitions can support nursing teaching and future researches of the phenomenon.
In addition to the frequency of the ND, it is relevant to determine the accuracy of the defining characteristics for specific populations. This knowledge can help understanding how the human response is presented, with its antecedents and consequences, and can also support a quality care (40) . A content validation study developed with nurses from the Czech Republic (41) found that the DCs positioning to ease pain, observed evidence of pain, verbal report of pain, protective gestures, protective behavior, changes in heart rate, expressive behavior and sleep disorders were considered by the nurse judges as major DCs, that is, the DCs that best defined patients with This way, the patient also benefits, since the nurse will have consistent evidence to make an ND and determine the next stages of the nursing process (40) .

Conclusion
Pain is a frequent event in ICU patients and this study considers particularly those who can not communicate.
The main characteristic of this population hinders the identification of clinical evidences that lead to the ND Acute Pain.
Despite the scarcity of studies addressing this issue for this population, there are methods to describe and evaluate data that allow studying this phenomenon with the use of procedures that are commonly present in critical care.
This way, the use of proper procedures and the identification of the defining characteristics and related factors of this ND must be in the methodology that will lead to the accuracy of these elements for this population.