Variables associated with peripherally inserted central catheter related infection in high risk newborn infants 1

OBJECTIVE: to relate the variables from a surveillance form for intravenous devices in high risk newborn infants with peripherally inserted central catheter related infection. METHODOLOGY: approximately 15 variables were studied, being associated with peripherally inserted central catheter related infection, this being defined by blood culture results. The variables analyzed were obtained from the surveillance forms used with intravenous devices, attached to the medical records of newborn infants weighing between 500 and 1,499 g. The statistical association was defined using the Chi-squared and Student t tests. The study was approved by the Research Ethics Committee of the Instituto Fernandes Figueira under process N. 140.703/12. RESULTS: 63 medical records were analyzed. The infection rate observed was 25.4%. Of the variables analyzed, only three had a statistically-significant relationship with the blood culture - the use of drugs capable of inhibiting acid secretion, post-natal steroid use, and undertaking more than one invasive procedure (p-value of 0.0141, 0.0472 and 0.0277, respectively). CONCLUSION: the absence of significance of the variables of the form may be related to the quality of the records and to the absence of standardization. It is recommended that the teams be encouraged to adhere to the protocol and fill out the form.


Introduction
Peripherally Inserted Central Catheters (PICC) are increasingly used in Neonatal Intensive Care Units (NICU) due to their characteristics of ease of insertion and prolonged period of use. However, their use presents risks related to handling, such as mechanical complications and problems resulting from infectious processes (1)(2) .
In order to increase the safety of using these devices, international organizations, including the Center for Disease Control (CDC), have established protocols for the prevention of infection related to the intravascular catheter, which standardize the practice of insertion and maintenance of venous catheters, including the PICC.
Adherence to the protocol requires well-trained teams and periodical monitoring of the procedures and actions defined, through standardized instruments (checklists) or surveillance forms (3) .
In general, the checklists or the surveillance forms are developed in accordance with norms and recommendations from regulatory agencies, and are constructed based on a consensus among the professionals involved with the care processes, often without a process of validating the instrument used. In this regard, it is necessary to identify whether the items used in these documents are relatable to the outcome of infection.  (4) or who were transferred due to any situation were excluded from the study. The sample size was calculated considering a prevalence of infection due to use of the PICC of 20%, a confidence level of 95%, and an error level of 10%.
Based on these parameters, the minimum sample necessary for calculating the frequency of infection is 61 NB. The Student t-test was adopted for analysis of the statistical association of numerical variables, and the Chi-squared or Fisher tests were adopted for categorical variables with the infection. A level of significance of 5% was adopted for all the analyses.

Results
A total of 63 medical records were analyzed, of which 53.9% (34/63) were of male NB. This population's mean birth weight was 1,105.15±235.2 grams (median of 1,115 grams), the gestational age was of 31±2.5 weeks (median of 31), Apgar at the 1 st minute of 1 to 9 (median of 6) and at the 5 th minute of 4 to 10 (median of 9) and the length of inpatient treatment was 42.5±23.1 days (median of 36.5 days).
In relation to the care provided, it was ascertained that 81% (51/63) of the NB received some sort of ventilatory support, and that 86.2% (28/51) had records for CPAP and mechanical ventilation. Invasive procedures were observed for 100% of the NB, with 82.4% (52/63) having records of more than one invasive procedure. The variables analyzed are described in Table 1. When the blood culture was related to the use of  Table 2.   (Table 3). that effectively used, in relation to the blood culture (Table 4). Records referring to undertaking pre-puncture aseptic procedures were found in 75% (

Discussion
The study assessed the relationship between the blood culture result in the variables of the surveillance form for intravascular devices for high-risk NB using PICC in a NICU. The infection rate calculated in this study was shown to be similar to that of other studies (1,5) .
The association observed between the results of the blood culture and the use of drugs capable of inhibiting acid secretion (Ranitidine), post-natal steroids (Hydrocortisone and Dexamethasone) and undertaking more than one invasive procedure has already been described as a risk factor for late-onset sepsis in NB.
In the case of ranitidine, the action inhibiting the secretion of acid from the gastric juices, a substance which has an effect on pathogenic agents, would increase the probability of infection. In relation to the use of post-natal steroids, the frequency of positive blood cultures may be explained by the action of these drugs on the immune system (6)(7) . The simultaneity of invasive procedures was also shown to be an important factor in the predisposition to infection, which can be explained by the larger number of gateways for pathogenic agents and by the larger number of devices to be handled (4) .
In relation to the length of the PICC, the mean estimated to be inserted in the NB was 21.3 cm.
However, what was observed was that only 10.0 cm were effectively inserted. This situation may represent an increased risk for infection, as the un-inserted portion of the PICC is subject to colonization through handling and through contact with the microbiota of the NB's skin, in this way possibly becoming a focus for the migration of microorganisms to the blood stream (3) .
The analysis of the pre-puncture asepsis actions evidenced chlorhexidine and PVP-I as the products used most, this last not being recommended for NB below 2,500 g, due to the transcutaneous absorption of the iodine, which can lead to hypothyroidism (12) .

Conclusion
The quality of the records was shown to be an important stage for recovering the care history for the PICC and the surveillance of the same, pointing to the need to raise the teams' awareness regarding commitment to keeping records up-to-date, complete, and appropriately filled out. The use of standardized forms is recommended, with closed and categorized questions, periodic training, and encouragement for the teams to adhere to the protocol and to fill out the form.
It is also recommended that further studies be