Nursing diagnosis risk of infection in patients in the postoperative period: a cross-sectional study


Fabiane Rocha Botarelli1, Quéren Jemima Rodrigues Queiroz2, Ana Paula Nunes de Lima Fernandes1, Jéssica Naiara de Medeiros Araújo1, Marcos Antonio Ferreira Júnior1, Allyne Fortes Vitor1

1Federal University of Rio Grande do Norte
2Natal Hospital Center

Aim: To compare the risk factors associated with the nursing diagnosis risk of infection in patients during the postoperative period, according to the taxonomy of NANDA-I, with factors present in patients with established infection.
Method: an analytical, cross-sectional study with 80 patients in the postoperative period.
Results: risk factors: inadequate primary defense (ruptured skin and invasive procedures), smoking and inadequate secondary defense by the suppressed inflammatory response were statistically significant in patients at risk of infection. In the group of patients with an established infection, there was a positive association for inadequate primary defense (ruptured skin and invasive procedures) and decreased hemoglobin.
Discussion: for an overall assessment of the predictive factors for infection, an integrated multifactorial analysis, including the whole perioperative period is required.
Conclusion: inadequate primary defense for invasive procedures and ruptured skin and decreased hemoglobin were factors associated with both the risk and for the presence of infection.
Descriptors: Nursing Diagnosis; Infection; Risk Factors; Postoperative Complications.



Faced with this problematic area, the World Health Organization chose to focus on actions aimed at surgical safety in health care as the second Global Challenge for Patient Safety. The campaign "Safe Surgery Saves Lives" provides protocols in order to reduce the occurrence of adverse events and incidents, as well as mortality from surgical procedures(2-3).

In this context, we emphasize the importance of nursing diagnoses (ND), which are an essential stage of the nursing process, established by accurate clinical judgment in identifying human responses to health conditions or vulnerability. This is done by collecting data obtained from the patient’s history and physical examinations, and providing support to the selection of nursing interventions, monitored by the nursing results(5).

The International NANDA taxonomy (NANDA-I) consists of a system of nursing diagnosis classification that instrumentalizes nurses to improve clinical reasoning for correct identification of ND, in order to guide the assistance and provide transformation of practice(6).

In this study, emphasis was given to the Domain 11 Security/Taxonomy protection of NANDA-I, as defined as: being out of danger, injury, or damage to the immune system; conservation against loss and safety protection; and the absence of hazards. In this area, the nursing diagnosis (ND) was called the risk of infection, the increased risk of being invaded by pathogenic organisms(6).

Based on these, this study aimed to compare the risk factors associated with the nursing diagnosis risk of infection in patients in the postoperative period, according to the taxonomy of NANDA-I, with the factors present in patients with established infection.



This was an analytical, cross-sectional study conducted in a university hospital in the city of Natal, Rio Grande do Norte, Brazil. The population consisted of patients admitted to the surgical units of this institution in the postoperative period.

The sample size calculation was based on the formula developed for studies with an infinite population, namely: N= (Zα P. Q.)/E2, where N = sample size; Z = confidence level; P = prevalence of patients treated in surgical units; Q = prevalence complement (1-P); E= sampling error. A confidence level of 95% and a sample error of 5% were adopted. After calculation, the sample consisted of 80 individuals.

For the sample, participants who were present in the respective units at the time of data collection were considered. Samples were of the consecutive type, that is, the selected individuals were grouped sequentially.

Inclusion criteria: postoperative patients who had been hospitalized in the surgical clinic unit of the hospital, aged 18 years or older, who were cognitively and emotionally capable of answering the questions and being submitted to a physical examination. Exclusion criteria: patients who had emergency situations during the time of data collection.

For analysis of the cognitive conditions of the selected patients, the examiners applied the Mini Mental State Examination test (MMSE). The score for the inclusion of participants considered suitable by the examination took place as follows: >15 points (if illiterate), >22 points (if patients had 1 to 11 years of study) and >27 points (if patients had over 11 years of study). For the analysis of emotional conditions, the participants who considered themselves fit at the time of data collection were included.

Data collection occurred from October to December 2012, through a questionnaire consisting of a history and a physical examination script, based on the Taxonomy II of NANDA-I, with emphasis on Domain 11 Security/Protection.

Figure 1 presents the risk factors assessed according to Taxonomy II of NANDA-I and the method for obtaining data for the study. Risk factors: changes in the pH of the secretions, decreased ciliary activity, premature rupture of membranes, stasis of body fluids, prolonged rupture of membranes, malnutrition, and inadequate vaccination were not included for evaluation because of the impossibility of measurement or by the inadequacy of the specific clinical condition after surgery.


Picture 1 - Risk factors evaluated in the ND Infection Risk of the taxonomy II of NANDA-I in patients in the postoperative period. Natal, 2012.
Nursing Diagnosis: Infection Risk
Domain 11: Safety/Protection
Definition: Risk of being invaded by pathogenic microorganisms
Risk factors Assessment
Increased environmental exposure to pathogens Unit nursing records assessment
inadequate primary defenses  
Inappropriate peristalsis Physical exam
Ruptured skin (* CV ** PI) Physical exam
Smoking Anamnesis
Traumatized tissue (trauma, tissue destruction) Physical exam
Inadequate secondary defenses  
Haemoglobin decreased Anamnesis (laboratory data)
immunosuppression Anamnesis (immunosuppressive drugs)
leukopenia Anamnesis (laboratory data)
Suppressed inflammatory response Anamnesis (anti-inflammatory drugs)
Chronic disease (diabetes, obesity) Anamnesis
Invasive procedures Physical exam and anamnesis
Subtitle: * VC-venous catheter; ** IP-invasive procedure.
Source: Prepared by the authors, 2012.


For diagnostic inference, the diagnostic reasoning process of Gordon was used(7). Thus, the most important data related to the real needs of patient identification was collected, interpreted and grouped, according to the similarity of the information or the existence of any relationship between them. Subsequent to this, there was the selection of the diagnosis by comparing the related factors contained in the ND infection risk of the Domain 11 Security/Protection of NANDA-I with data obtained in the patient assessment. After this last step, each researcher performed the diagnostic inference individually, and then there was a meeting between the researchers to analyze the agreement and consensus in the assessment of the diagnosis, in order to indicate the permanence or exclusion of patients in this study.

The data was entered electronically in a Microsoft Excel spreadsheet®, in which the sociodemographic and clinical variables, the presence of the ND risk of infection and risk factors were recorded. Later, the data was processed and analyzed by a statistical package using descriptive statistics, with the presentation of frequency distribution, mean, standard deviation, and confidence intervals (95% CI). To verify the normality of the findings, we used the Kolmogorov-Smirnov test. The significance level was 5%.

The statistical chi-square test and Fisher's exact test were used to verify the association between the categorical variables of interest, with a significance level of p<0.05. The Phi coefficient, which aims to estimate the intensity of the relationship between two dichotomous and qualitative variables, was used as a measure of association. Its measurement reduces the significance of the prediction error obtained in the chi-square test, which makes it the most accurate analysis. Their values ranged from 0 (no relation) to 1 (perfect relationship) and had the following combination of scores: 0-0.2 (negligible); >0.2-0.4 (weak); >0.4-0.6 (moderate); >0.6-0.8 (b) and >0.8-1.0 (very b).

This study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, with the opinion number 121,028, in accordance with the provisions of Resolution No. 466/12 of the National Health Council, which sets the legal and ethical principles governing scientific research involving human subjects(8).



As shown in Table 1, of the 80 participants, 60% were male and 40% female, with a mean age of 47.46 (± 16.15) and the majority, 70%, had been submitted to abdominal surgery.


Table 1 - Socio-demographic and clinical characteristics of patients in the postoperative period. Natal, 2012.
Variables n % *IC (95%)
Male 48 60 (48,4 - 70,8)
Female 32 40 (29,2 - 51,6)
Type of surgery      
Abdominal 56 70 (58,7 - 79,7)
Head / Neck 10 12,5 (6,2 - 21,8)
Thoracic 8 10 (4,4 - 18,8)
Orthopedic 5 6,3 (2,1 - 14,0)
Vascular 1 1,3 (0,0 - 6,8)
Presence of infection 36 45 (33,8 - 56,5)
Total 80 100  
  Media **DP ***K-S (Valor p)
Age (years) 47,46 16,15 0,586
Subtitle: * CI - confidence interval; ** SD - Standard Deviation; *** K-S - Kolmogorov-Smirnov test
Source: Prepared by the authors, 2012.


It was found that the entire sample had problems related to infection, both by the risk inferred by the ND Risk of Infection in 55% of patients or by the condition set and found by the records in medical charts in 45% of participants.

For describing the results, the group (PI) included participants with the presence of infection and the group (RI) included those with the infection risk. As to the average age, both groups showed similar results, with 47.93 (±16.14) years for the RI group and 46.89 (±16.36) years for the PI group. Regarding the number of days after surgery, the mean RI group was 2.94 (±2.10) days, which approximated to (±2.61) days for the PI group. These three variables showed normal distribution by the Kolmogorov-Smirnov test and a statistically significant association (p<0.001).

Table 2 lists the risk factors found in both groups and the statistical association of each. In the RI group, a statistically significant association was found for: the primary defense being inadequate for invasive procedures (p<0.0001) with the strength of the association being b by the phi coefficient 0.660 (p<0.0001); the primary defense was inadequate for broken skin (p<0.0001), with strength of association being very b by the phi coefficient 0.849 (p<0.0001); lower hemoglobin (p=0.021) in association with a weak force by the phi coefficient 0.258 (p=0.021); smoking (p=0.027), with the strength of association being weak by the phi coefficient 0.247 (p=0.027) and inadequate secondary defense by the inflammatory response was suppressed by the use of anti-inflammatory drugs (p=0.027) with the strength of association being weak by the phi coefficient 0.234 (p=0.037).

In the IP group, the risk factors with a statistically significant association were: the primary defense was inadequate for invasive procedures (p<0.0001) with strength of association being weak by the phi coefficient 0.392 (p<0.0001); the primary defense was inadequate for broken skin (p<0.0001) with force by association showing a moderate phi coefficient 0.595 (p<0.0001) and decreased hemoglobin (p=0.001) with the strength of association being weak by the phi coefficient 0.364 (p=0.01). (IS THIS WHAT YOU MEAN?)


Table 2 - Association of NANDA-I Taxonomy II risk factors among participants in postoperative with the ND risk of infection (RI) and participants with the presence of infection (PI). Natal, 2012.
   Group IR Group PI
Risk factors p valor Phi p valor Phi
Chronic disease - Obesity 0,475¹ - 0,207¹ -
Chronic Disease - Diabetes Mellitus 0,083² - 0,260² -
inadequate primary defense < 0,0001² 0,660 p<0,001 < 0,0001² 0,392
(Invasive procedures) p<0,001
inadequate primary defense < 0,0001² 0,849 < 0,0001² 0,595
(Ruptured skin) p<0,001 p<0,001
Inadequate primary defense 0,027² 0,247 0,258² -
(Smoking) p=0,027
inadequate primary defense 0,086¹ - 0,086¹ -
(Traumatized tissue)
inadequate secondary defense 0,045¹ 0,234 0,248¹ -
(Suppressed inflammatory response) p=0,037
Haemoglobin decreased 0,021² 0,258 0,001² 0,364
p=0,021 p=0,01
Subtitle: 1- Fisher's exact Test, 2-Chi-square test; * Phi-phi coefficient. RI: Risk of infection; PI: Presence of infection
Source: Prepared by the authors, 2012.


For the comparison of the predictive factors for infection between the groups, it was found that there was a positive association for the inadequate primary defense for invasive procedures, inadequate primary defense for broken skin, and decreased hemoglobin. As for the strength of association of these variables between groups, there was convergence to the decrease in hemoglobin (weak), little difference in the strength of association for broken skin (very b in the RI group and moderate in the PI group), and much disagreement for inadequate primary defense for invasive procedures (b in the RI group and weak in the PI group).



Most of the participants were young adults, with an average age of 47.46 years. At this stage, the risk of infection may occur due to clinical conditions in the preoperative phase and the presence of comorbidities. A recent study identified 100% RI in adults and elderly patients; however, the elderly ones were more susceptible due to losses in the functional capacity of the skin, especially in the subcutaneous tissue, sebaceous and sweat glands by dryness, and cutaneous weakness(10).

As for the postoperative days, it was observed that both groups had a similar average number of days. However, the occasion of this finding indicates great concern in terms of the small number of days after surgery and the finding of the presence of infection in a significant number of the population.

The postoperative time is an important risk factor, because the longer the stay, the greater the exposure to pathogens, the greater the manipulation of the surgical wound, and the greater the likelihood of developing an infection(11).

For an overall assessment of the predictors of infection, an integrated complex and multifactorial analysis, including the whole perioperative period, is required. Thus, not only should the time after surgery be taken into consideration, but also the preoperative clinical condition, the surgical technique, the technical skill of the surgeons, environmental conditions and the number of people in the operating room, the condition of the surgical materials, the quality of the care provided, and the risks of the postoperative period.

By analyzing these events in hospitals with large movements of students in training, studies have shown that residents with few technical skills increase the surgical time and cause greater exposure of tissues, with the consequent reduction of the systemic defenses and emergence of infections(10,12).

In this context, the World Alliance for Patient Safety has an important contribution in proposing the second global challenge that gives priority attention to the fundamentals and practices of surgical safety and prevention of surgical site infections, safe anesthesia, confident surgical teams and indicators of surgical care(2,3).

Therefore, the surveillance described in this Alliance comprises the continuous and systematic collection, analysis, evaluation and dissemination of data of interest in patient safety. Among its methods, the monitoring of nursing has a prominent position(2-3), in this sense, regarding the evaluation of nurses to surgical patients, the use of the NANDA-I taxonomy enables the identification of the ND risk of infection of the Domain 11 Security/Protection, as well as the implementation of interventions and evaluation of the expected health outcomes.

In other studies, the ND has been identified in almost 100% of patients throughout the perioperative period, especially in the postoperative period, by the biggest risk factors, such as surgical trauma for invasive procedures, broken skin for other invasive procedures, decreased hemoglobin by blood loss and inflammatory response suppressed by the use of anti-inflammatory drugs(13,14).

Regarding the results of this study, 100% of the sample had problems related to infection; when the ND was not inferred, it was found that the participant already presented some type of infection. As for the risk factors that were related to infection, the inadequate primary defenses for broken skin and invasive procedures had a positive association for the two groups and the correlation strength by the phi coefficient was very b and moderate, respectively.

Similar results were observed in a study in which all participants had skin integrity impaired by secondary mechanical factors and invasive procedures. The findings showed that the act of submitting to invasive procedures (p<0.0001) and the broken skin condition (p<0.0001), which is required in most surgical procedures, increases the likelihood of the risk of infection. The loss of the skin's protective barrier facilitates the infection process by exposure, in addition to hampering or impairing the arrival of amino acids, glucose and oxygen to the tissue, which are necessary to maintain its protective function(10,11,14).

Another risk factor with a positive association to the groups was decreased hemoglobin, but with poor correlation of strength in both. A cross-sectional study involving patients in the postoperative period found that of those who received a blood transfusion, 26.7%, had developed infection. The greater the surgical time, the greater the likelihood of significant blood loss, which may result in the need for a blood transfusion and the patient’s exposure to another means of infection. Furthermore, an intraoperative blood transfusion with allogeneic leukocytes containing components has been suggested as a predictor of infection(15). Moreover, the presence of anemia in postoperative patients impacts on their immunity and susceptibility to infections with increased morbidity and mortality(12).

Smoking and suppressed inflammatory response were risk factors associated with the RI group, but with weak correlation strength. Despite the lack of statistical significance for the PI group, literature data indicate that these characteristics have played an important role in determining the likelihood of infection after surgery. Prior clinical conditions, such as patients with chronic diseases, smokers, those who are hypertensive or obese have demonstrated greater predisposition to infections(10,11,13).

A cohort study that analyzed infection predictors of postoperative myocardial revascularization surgery patients identified smoking as a risk factor for infection (p=0.001). Individuals who smoke presented decreased defense mechanisms for the respiratory system. Thus, the intubation required in some surgical procedures exposes the airway to pathogens and increases the risk of infection(16).

The limitations of this study were that the sample obtained in the population in a specific condition after surgery was small for the generalization of the results and the time of recruitment was short to allow a representative sampling.

However, the findings do contribute to guiding future studies that will present more evidence to investigate the association of risk factors described in NANDA-I with the occurrence of infection, as well as to support the inclusion of new factors for the nursing surveillance of patients’ safety in operative conditions.



When relating the risk factors of the RI group with the characteristics of the PI group, it was observed that the primary defense was inadequate for the invasive procedures and broken skin, and decreased hemoglobin showed a positive association, such as predictors of infection.

Based on clinical reasoning of the assessment of the ND risk of infection of the NANDA-I taxonomy, it was realized that their risk factors allowed the indication of the relationship with the occurrence of infection in patients in the postoperative period.

In addition, this study allowed a preliminary analysis of the risk factors that must be evaluated by nurses to determine the ND risk of infection and to support actions to prevent this. As surgical site infections are a major threat to patient safety, it is of paramount importance to make use of the recommendations of the World Patient Safety Alliance with regard to safe surgery, in order to minimize their occurrence.

Due to the high presence of NDs under the study in patients in the postoperative period, it is suggested that studies with a larger sample and more evidence are performed, as well as the analysis of other predictive factors for infection that are not described in the taxonomy of NANDA-I. This recommendation for further research is based on the assertion that the early identification of risk factors promotes interventions that decrease the possibility of infection and favor safe care.



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All authors participated in the phases of this publication in one or more of the following steps, according to the recommendations of the International Committee of Medical Journal Editors (ICMJE, 2013): (a) substantial participation in the planning or preparation of the manuscript or the collection, analysis or interpretation of data; (b) elaboration of the work or performance of critical review of the intellectual content; (c) approval of the submitted version. All authors declare for any purposes that the content related to all aspects of the manuscript submitted to OBJN is their responsibility. They ensure that the issues related to the accuracy or completeness of any part of the article have been properly investigated and resolved; thus exempting the OBJN of any joint participation in any imbroglios on the matter at hand. All authors declare that they have no conflict of interest, whether financial or relationship, to influence the drafting and/or interpretation of the findings. This statement has been digitally signed by all authors as recommended by the ICMJE, whose model is available in http://www.objnursing.uff.br/normas/DUDE_final_13-06-2013.pdf



Received: 08/21/2015
Revised: 05/20/2016
Approved: 05/21/2016