Rev. Latino-am. Enfermagem Artigo Original the Nursing Diagnosis of Risk for Pressure Ulcer: Content Validation Cássia Teixeira Dos Santos 2

Objective: to validate the content of the new nursing diagnosis, termed risk for pressure ulcer. Method: the content validation with a sample made up of 24 nurses who were specialists in skin care from six different hospitals in the South and Southeast of Brazil. Data collection took place electronically, through an instrument constructed using the SurveyMonkey program, containing a title, definition, and 19 risk factors for the nursing diagnosis. The data were analyzed using Fehring's method and descriptive statistics. The project was approved by a Research Ethics Committee. Results: title, definition and seven risk factors were validated as " very important " : edema, impaired circulation, and decrease in oxygenation and in tissue perfusion. The risk factor of hyperthermia was discarded. Conclusion: the content validation of these components of the nursing diagnosis corroborated the importance of the same, being able to facilitate the nurse's clinical reasoning and guiding clinical practice in the preventive care for pressure ulcers. 1 Paper extrated from Master's Thesis " Development and content validation of nursing diagnosis risk of ulcer pressure " , presented to Escola de


Method
This is a Diagnostic Content Validation (DCV) study of the components of the ND of Risk for pressure ulcer, through the opinion of specialists (11) . The sample was made up of 24 nurses, members of skin and wound care study groups, from five hospitals in the southern region of Brazil, and one in the southeastern region.
The specialists were selected according to the following inclusion criteria: to participate or have participated in a skin and wound care study group for, at least, one year; to have had clinical practice in skin care, particularly in care for patients at risk for PU, for at least one year; to use a PU prevention and treatment protocol with application of the Braden scale as the instrument for predicting risk; and to respond to the instrument within the time period established of 60 days. Those nurses who met the inclusion criteria but who were absent from work during the period of the study due to holiday, absence and/or leave were excluded from the study.
For data collection, the SurveyMonkey program was used, available free of charge on the Internet, in which was created a questionnaire with a link generated automatically, which was sent by email to the study participants. The responses were stored on the program's database. The first part of the instrument contained data on the specialists' characterization and professional and academic profile. The second part of the instrument focused on data of the DCV of the ND Risk for pressure ulcer, and contained the title and definition of this new ND, in which the specialists were to place an "X" on a five point Likert-type scale, covering one of the following possibilities: 1 -strongly disagree; 2 -disagree; 3 -do not know; 4 -agree, and 5 -strongly agree. Following that, the instrument presented the risk factors which made up the ND with their respective conceptual definitions and, in addition, a five point Likert scale in which the specialists were to mark one of the following alternatives: 1-does not indicate risk for PU; 2 -indicates little risk for PU; 3indicates moderate risk for PU; 4 -indicates high risk for PU and 5 -indicates a very high risk for PU. Along with the data collection instrument, the respondents were also sent an informative pamphlet on how to fill out the instrument and return it to the researcher, and on the ethical aspects of the study. The return of the filled-out instrument was taken as acceptance to participate in the study. The analysis related to the ND's DCV was also statistical, taking into account the score attributed by the specialists to each one of its components and, based on that, the weighted average of the same indicated on the Likert scale with variation between 1 and 5 points, where: 1=0; 2=0.25; 3=0.50; 4=0.75 and 5=1 (11) .
Any component (title, definition, risk factor) which received a mean greater or equal to 0.80 was considered "very important"; those with a mean below 0.80, but above 0.50, as "important"; and those with a mean equal to or less than 0.50 were discarded, as they were not considered important for this ND in the specialists' opinion (11) . The project was approved by the Research Ethics Committee, under Protocol 13-0034.

Results
The study involved the participation of 24 specialist nurses, the large majority of whom were female  (Table 1). Source: Santos (7) .
*median (25%-75%) The content validation of the ND Risk for pressure ulcer included the analysis of the title, definition and 19 risk factors which make up the same.
The title and the definition were validated with a mean of ≥ 0.80 (Table 2).

Components of the ND Risk for pressure ulcer Mean
Title -Risk for pressure ulcer 0.92 Definition -Risk of tissue damage in the skin and underlying tissue, as a result of compression of the soft tissues generally over a bony prominence, during a time period capable of causing local ischemia and, consequently, necrosis 0.87 Source: Santos (7) .
Nineteen risk factors for the ND Risk for pressure ulcer were submitted to DCV. Seven (56.8%) were validated as "very important", with a mean of ≥ 0.80 (Table 3).
(continue...) been used both for developing new NDs and for refining those already existing, with a view to greater accuracy (7) .
Among the limitations of validation studies is the initial difficulty for defining the inclusion criteria for specialists, as there is no consensus in the literature in relation to the ideal number for the sample, besides the difficulty of finding nurse specialists in the areas of interest for investigation (8)(9)(10) . However, Similarly, the definition of the ND also presented a mean which showed agreement among the specialists, which demonstrates clarity and objectivity, based in the physiopathology and etiology of the PU.
The importance of a specific ND, with a clear title and definition regarding the risk of PU, has been evidenced by studies (12)(13)(14) which have demonstrated that this clinical situation is common, both in patients  (17) .
The risk factor of skin moisture received a mean of 0.88, reaffirming its importance for the development of PU. The exposure of the skin to humidity, principally to urine and feces, associated with abrasive forces such as surface friction and shearing forces, predisposes to an increase in irritation, causing maceration and ulceration and -once the PU is installed -the prognosis is negative regarding healing (14) .
The risk factor of malnutrition was validated with a mean of 0.84. Under conditions of weight loss, the musculature becomes hypertrophic, and the thin panniculus causes a break in the skin. With deficiency in nutrients, change also takes place in tissue healing, in the inflammatory reaction, and in the immune function when exposed to pressure. Poor nutrition can also be associated with low weight, indicated by the Body Mass Index (BMI <20), which favors the development of PU over the bony prominence, associated with pressure (13,(18)(19) .
The risk factor of alteration in sensations was validated with a mean of 0.82. Reduction in sensation occurs due to illnesses which trigger this form of harm, such as neurological ones, or through the use of analgesics and sedatives which, besides reducing sensation to physical stimulus, harm mobility. This is due to reduction of the normal stimulus to pain, leading the patient not to relieve prolonged pressure (19) .
Eleven risk factors were considered "important" by the specialists, with means between 50 and 80 points: In the light of the numerous illnesses related to the circulation, this risk factor deserves attention and has been described in research on PU (12,21) , principally among older adults, whose circulatory system is impaired by the characteristics of senescence.
The risk factor of dehydration was validated with a mean of 0.77. Dehydration impairs the vital functions of circulation, reducing the oxygenation of the tissues.
It is known, furthermore, that deficit in ingesting liquids causes reduction in the skin turgor, this becoming increasingly fragile, which, coupled with the forces of abrasion (friction, pressure and shearing), increases the risk of ulceration (18) . in nutrients. When the tissue fluid increases and leaks outside the cells, the pressure on the blood vessels increases and, therefore, the blood flow and oxygenation of the tissues reduce, favoring ulceration (19) .
The risk factor of obesity was validated with a mean of 0.70. In obesity, there is the formation of adipose tissue, which reduces the vascularization of the skin surface, which can favor ischemia in the tissues and the development of PU, when some area of the body is subjected to pressure. Associated with this, the obese individual may have other comorbidities such as diabetes mellitus, making her still more vulnerable to PU (13,(18)(19) .
The risk factor of decrease in serum albumin level was validated with a mean of 0.68. Albumin is the most abundant protein in the plasma, used for determination of nutritional status. In low concentration, it causes changes in oncotic pressure and the formation of edema, which compromises the diffusion of oxygen and nutrients to the tissues, predisposing to hypoxia and cell death (13,18) .
The risk factor of anemia was validated with a mean of 0.70. This consists of the reduction in the quantity of hemoglobin in the blood stream, which is responsible for transporting oxygen to cells and tissues. The reduction of oxygen for the fibroblasts, cells responsible for healing of the tissues, reduces the formation of collagen and increases the tissue's susceptibility by precipitating ischemia and necrosis (13,19) . Supporting this, one study factors such as immobility, malnutrition or obesity and extremes of age (prematurity or aging), makes the risk of PU imminent (18) .
The results obtained in this study were sent to the Diagnosis Development Committee (DDC) of the NANDA-I, responsible for analyzing proposals for new diagnoses for this taxonomy, and were approved and published in its most recent edition (6) with some modifications such as maintaining the risk factor of hyperthermia.

Conclusion
The DCV of the new Nursing Diagnosis Risk for Pressure Ulcer, undertaken by specialist nurses, It is also understood that the classification systems