RESEARCH ARTICLES

Characterization of infections related to health care in a neonatal intensive care unit

Cecília Olívia Paraguai de Oliveira^I; Nilba Lima de Souza^II; Edna Marta Mendes da Silva^III; João Batista da Silva^IV; Eider Maia Saraiva^V; Clara Tavares Rangel^VI

^IUndergraduate Student in Nursing, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil, E-mail: cecília_olivia@yahoo.com.br,
^IIProfessor, PhD, Nursing Department Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil, E-mail: nilbalima@ufrnet.br.
^IIINurse, Federal University of Rio Grande do Norte, Januário Cicco Maternity School, Hospital Infection Control Committee, Natal, Rio Grande do Norte, Brazil, E-mail: ednaguga@hotmail.com.
^IVPhD Student, Federal University of Rio Grande do Norte, Postgraduate Program in Health Sciences. Assistant Professor at the State University, Rio Grande do Norte. Natal, Rio Grande do Norte, Brazil, E-mail: joaobatista@uern.br.
^VUndergraduate student in Medicine, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil, E-mail: eidersaraiva@hotmail.com.
^VIUndergraduate Student in Nursing, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil, E-mail: claratrl@hotmail.com.

ABSTRACT

This study aimed to characterize neonatal infections related to health care in a neonatal intensive care unit (NICU) of a maternity school in Natal, Rio Grande do Norte, Brazil. This is a quantitative, retrospective and documentary study which was conducted through a questionnaire applied to 70 newborn medical records, who were hospitalized at the NICU in 2009. The annual nosocomial infection rate was approximately 14.6%, with a total of 100 cases of infection, 90% related to the bloodstream. Intrinsic and extrinsic risk factors were considered for the neonate, highlighting as intrinsic factors, birth weight and gestational age at delivery, and as extrinsic factors, invasive procedures and the high rate of hospital permanence. It was concluded that the occurrence of infection was more frequent in premature infants weighing less than 1,500g, and the bloodstream was the primary patient infection site , diagnosed by clinical and hematological parameters.

Keywords: Nosocomial infection; neonatal nursing; neonatal intensive care unit; epidemiologic surveillance.

INTRODUCTION

The occurrence of nosocomial infection has been identified as an important public health problem in Brazil and in the world. It is defined as what is acquired after the patient's admission and manifests during their hospitalization or even after discharge, when related to hospitalization or hospital procedures¹.

Recently, some authors have suggested adopting the denomination infection related to health care (IRHC), as to recognize that such injuries do not occur exclusively in hospitalization situations, but that they may be due to the patients' contact with other types of care modalities².

The NICU is a point-of-care for high complexity patients, which makes it essential to investigate nosocomial infection cases, viewing different factors such as the extreme susceptibility of these patients; the emergence of increasingly resistant bacteria, due to indiscriminate use of antibiotics; the lack of a systematized nursing work process; and the high hospital cost for this treatment. It is, however, a complex matter in which all the efforts to improve this problem are of paramount importance, making evident need to do surveillance of the IRHC for the neonatal population.

Thus, the objective of this study was to characterize the neonatal infections related to health care in a NICU at a maternity hospital.

LITERATURE REVIEW

The IRHC in neonatology contemplates the care-associated infections, such as those related to its failure. This new concept is to create a greater scope for the prevention of infections in the prenatal , perinatal and neonatal periods³.

In the neonatal period, the IRHC acts as an important limiting factor for life, increasing morbidity and mortality in this age group. In these neonates, the infection via hospital occurs within the first 48 hours of life, having as a vehicle the mother, the hospital environment, equipment or the health team³.

The Ministry of Health, whose actions are oriented measures of nosocomial infection control, classifies all neonatal infections as hospital origin, except those that are acquired via transplacentals or associated with the rupture of amniotic membranes for a period exceeding 24 hours before delivery^1,3.

The IRHC affect more than 30% of the neonates, and when compared to the pediatric population of a greater age, their rates can be up to five times higher⁴. In Brazil, perinatal infections reported in 2010, septicemia was the most prevalent (27.9%) among the causes of late neonatal death (when the child is between 28 and 365 days of life)⁵.

The literature shows that the development of IRHC in neonates is related with the overcrowding of the units, the shortcomings of human resources, the infrastructure of health services, use of invasive procedures for long periods, as also to the factors of the newborn, such as gestational age at birth and birth weight^6,7. It is common knowledge that the incidence of IRHC in neonates is also related with the use of a central venous catheter and mechanical ventilation⁸. Other studies also confirm that care practices by nursing staff, as instrumentation of the newborn, also have a relationship with the IRHC⁹.

In Brazil, the number of IRHC is greater in university hospitals or schools, by caring for patients of greater severity, submitted to more complex and invasive procedures. It is known that the great flow of professionals and students also increases the incidence of IRHC^7,10.

Currently, there are no national consolidated data on the incidence of IRHC in neonatal units of intensive and intermediary care; there are only regional studies, which may vary according to the type of health care unit analyzed. This results in the need for new studies that might be indicators that govern control and reduction actions of IRHC in newborns.

METHODOLOGY

This is a descriptive study, a quantitative, retrospective, including the charts of all newborns (NBs) admitted to the NICU of the Maternity School Januário Cicco (MEJC) who acquired nosocomial infection (NI) late in the period January-December, 2009. This Maternity is situated in Natal, capital of the State of Rio Grande do Norte, Brazil.

This research field was chosen because it is a outsourced referential care unit for pregnancy and birth risk in the state of Rio Grande do Norte and the fact that the institution is a teaching and university hospital and have a NICU, and through this, implement actions with the nursing staff with the aim of preventing injuries to neonatal health.

70 Records were investigated in accordance with the notification of hospital infection recorded by the Commission of Nosocomial Infection Control), regarding newborn infants admitted to the NICU in the selected time period.

The criteria for the diagnosis of IH used were the settings from the Centers of Disease Control and Prevention (CDC), criteria of the National Nosocomial Infections Surveillance System (NNIS) and Decree no. 2,616 /98 of the Brazilian Ministry of Health, involving the patient's clinical, hematological factors and/or microbiological tests. For this study was considered, all the bacterial infections that occurred 48 hours after the birth, according to the criteria for the classification of nosocomial infection of the CDC and the Ministry of Health, proven or not by cultures^2,11.

The data were collected in the period from January to June of 2011 in the records of NRs and in the notification records of the IH formulated in accordance with criteria of the NNIS, completed and analyzed by the multi professional team of the CCIH at MEJC. All cases of NI were detected by means of an active search by professionals this committee.
A form was used with closed ended questions, containing two parts, the first relating to obstetric and neonatal data; and second, the variable objects of studies, which are considered to be risk factors for IRHC.

The information collected was stored in a specific database for the study, then analyzed by means of thesoftware Statistical Package for the Social Sciences (SPSS), version 17.0, through descriptive statistics.

This study was approved by the Research Ethics Committee of the University Hospital Onofre Lopes (CEP-HUOL) under protocol No.559/11. The Free and Informed Consent Form was signed by the director of the institution, as it is a retrospective study with a documentary analysis.

RESULTS AND DISCUSSION
 
In the year 2009, there were 607 newborns admitted in the NICU of MEJC at the selected time period. Of these, 70 have acquired at least a nosocomial infection, of whom 40 (57%) were male, and 30 (43 %) were females.

Some neonates presented more than one infection, totaling 100 late neonatal infections, which represented an average annual neonatal nosocomial infection rate of approximately 14.6%. Studies show that this rate usually varies between 5.9 and 39.6 %, depending on the characteristics of the unit and the NBs¹².

In relation to infected sites, six were identified. The primary bloodstream infections (sepsis) predominated, with 72 (72%) of the cases. Of these, 65 (90%) were without microbiological confirmation, considered as clinical sepsis, and the 7 remaining (10%) with microbiological confirmation (laboratorial sepsis). The number of newborns with clinically diagnosed sepsis was higher than the laboratory sepsis, because of the difficulty of the blood culture being positive, when the presence of biochemical entities which indicate a greater probability of a systemic infectious process, such as C-Reactive Protein¹³. There are studies that show that the CRP can also be used as a prognostic index for the monitoring of treatment⁹.

The second largest occurrence was pneumonia, with 13 (13%) cases, and the remaining were ocular infection, meningitis, enterocolitis and skin. These data are consistent with the literature, regarding the sepsis, the site of higher prevalence of the late neonatal infections^14,16, following in the second place to pneumonia in critically ill newborns¹⁷.

There was no difficulty in isolating the pathogens on cultures, in relation to the collection of this material, in terms of results, the most negative, mainly in blood cultures, showing an inconsistency with the patient's clinical profile. This fact may be related to lack of the microbiological identification automated method and the small volume of blood collection required in neonates (1 mL). Thus, of the 100 infections in the different sites submitted, only 13 (13%) had a microbiological confirmation, among them, the predominant etiologic agents were: 4 (31%), Pseudomonas aeruginosa, 4 (31% ), coagulase-negative Staphylococcus and 2 (15%) Klebsiella pneumoniae.

The coagulase-negative Staphylococcus was present in several studies as the predominant microorganism in IRHC in neonates, especially as regards the blood cultures^13,16,18. Some authors consider that the presence of this agent can be attributed to contamination, since these bacteria are naturally present on the skin of the patient and the health professionals, and can contaminate the sample during collection or laboratory handling13. This article highlights the need to address this in training courses for the incorporation of infection preventive measures, independent of the procedure to be performed, involving the practice of critical thinking¹⁹.

In 2009, the year of the survey data, there was no predetermined criteria by the CDC for the diagnosis of infections specifically in neonates, which in part made this work difficult, considering that the symptomatology of the IRHC, mainly to the bloodstream, is unspecific and can be confused with other diseases, and that thorough assessment of the patient's clinical and laboratory examinations is important. Already in 2010 the National Health Surveillance Agency (ANVISA) announced national criteria for IRHC in neonatology, which had recently been adopted by the CCIH of service, thereby facilitating the identification of current cases and reclassification of some old cases³.

It is worth pointing out that 100% of NBs made use of antimicrobials in the early hours of hospital admission, regardless of the diagnostic confirmation. In the literature, it is reported that the sensible use of antibiotics is recommended as an appropriate measure in NICU, but is not commonly practiced²⁰. The excessive use of these antibiotics facilitates the colonization of gram-negative hospital aerobics, and, in addition, the increase in the spectrum of antimicrobial activity does not always represent an advantage, since when very large it can provide the onset of a super-infection^10.21. Thus, the rational use of antimicrobial agents in the NICU becomes an essential weapon system in the prevention of nosocomial infections.

The risk factors were classified considering the NB's own intrinsics, and the extrinsic, related to the environment. The key in this age group are: intrinsics - low birth weight; prematurity; degree of immunological development; severity of the underlying disease; extrinsic - period of hospitalization; use of invasive procedures²². The intrinsics, 57 (81.4 %) neonates had a gestational age less than 37 weeks at birth. This is a risk factor for the bloodstream infections, since the risk of sepsis is inversely proportional to gestational age²³.

The selected sample, showed that 44 (62.9%) of the infants had low birth weight. Of these, 23 (32.9%) were born weighing between 1.001G and 1,500g and 21 (30%) weighing less than 1,001G. The literature shows that the NICU the incidence of IRHC increases the greater the prematurity and/or lower weight of the newborn^21,24. The premature NBs are the most group vulnerable to nosocomial infection, by a greater exposure to invasive procedures and severity of their current state²⁵.

Immunological status is considered an intrinsic risk factor. Newborns with less than 34 weeks of gestation did not have enough maternal antibodies, the defense system is immature, there is a deficiency in the production of humoral and cell factors, as well as deficits in the functioning of T cells, phagocytes and complement, all promoting the hematogenous spread of the infectious agent^26.27. The skin of the preterm newborn has a functional and immunological impairment and its barrier function and, in addition, can be easily damaged by serving as a gateway to the bloodstream organisms²⁰.

In relation to more relevant complications in the pregnancy period, it was emphasized that the rupture of amniotic membranes, with 36 (51.4%) cases, followed by hypertensive syndromes, with 27 (38.6%). Ruptured membranes occurring within six hours before delivery was recorded in 50 (71.4%) cases, while 13 (18.6%) showed this in a period of more than six hours, and in 7 (10%) there was no record.

Regarding the type of delivery, there was a fair distribution, for normal delivery, as well as for cesarean delivery. Respiratory distress at birth and need for intensive care was a common situation in 67 (95.7%) of the NB.

In relation to extrinsic factors, the use of invasive procedures totaled 206, with predominance of oro-gastric tube insertion, totaling 64 (31%) interventions, followed by invasive mechanical ventilation, with 51 (25%), and umbilical catheterization, with 48 (23%). It is worth pointing out that 39 (55.7%) NBs were submitted to three cited invasive procedures at admission. Recent studies report that it is an incumbency of clinicians to minimize risk of infection by performing invasive procedures only when necessary, and in the safest aseptic conditions²⁰. The primary bloodstream infections related to central catheters are the most common in NICU, and are in a large part explained by an inappropriate implantation technique and/or lack of continuous care at the site20. Other studies corroborate the findings of this present study^10,13,18.

Considering the asymmetric distribution of the data in relation to the days of admission to the NICU was taken the median (med=36) as a reference. It was observed that 36 neonates (51.4%) remained hospitalized for a period less than or equal to 36 days. The residence time in the NICU is one of the main risk factors for colonization and infection by hospital microorganisms. Early contact with the mother and breastfeeding promotes the colonization of the newborn by agents of maternal microbiota, protecting them, in part, against the colonization by hospital pathogens^14,18,21.

CONCLUSION

This study demonstrates that the nosocomial infections acquired by newborns in the year of 2009 in the MEJC NICU were more frequent in premature infants, weighing less than 1,500g), having the bloodstream as the main infection site diagnosed by clinical and hematologic evaluation of the patient. The main risk factors were related to the use of invasive procedures, such as the oro-gastric tube, invasive mechanical ventilation and the umbilical catheter, in addition to the severity of the underlying disease and hospitalization time.

The insertion of some invasive procedures, as well as the continuous assessment of all of them, and the evaluation of the patient's clinical status, are responsibilities inherent to the nurse, who should be able to prevent and identify signs and symptoms that may indicate the presence of nosocomial infection.

Thus, it is recommended that the nurses use nursing care systematization as a tool to minimize the risk factors and indices of IRHC in NICU, and, thus, raise efforts to reduce the high rates of morbidity and mortality in the neonatal period, having as a presupposition that a considerable proportion of nosocomial infections can be avoided with the implementation of prevention measures based on adequate technical and epidemiological knowledge, in addition to the administrative support from the institution.

As the limitations of this study, a deficiency was observed in the microbiological confirmation of the cultures, which could overestimate the number of primary infections in the bloodstream, given the high number of clinical sepsis cases. In addition to this, in the year regarding the collection and analysis of the survey data, there were no criteria determined by the CDC for the diagnosis of IRHC in neonates, which made it difficult in part this work by does not exist until then criteria of bloodstream infection specific to newborns. Therefore, a thorough evaluation of the medical charts of neonates for identification of the primary site of infection was of extreme importance.

The study has shown to be relevant with regard to the surveillance of nosocomial infections in neonates, to characterize these events in a local approach, emphasizing the importance of making prevention and control measurements, in order to reduce the indiscriminate use of antibiotics empirically, educating health professionals in relation to the asepsis when performing invasive procedures, thinking of a more secure NICU.

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Received: 20.04.2012
Approved: 24.01.2013