# Intelligent Neonatal Sepsis Early Diagnosis System for Very Low Birth Weight Infants
## 3 Materials And Methods
### Data Collection  
Clinical data used in this study were obtained from each patient's electronic medical records and included the following parameters:  
1. **birth weight** ;
2. **gestational age**;
3. **general aspect of the patient;
4. **presence of sepsis symptoms:** body temperature (fever, hypothermia), cardiovascular instability (bradycardia or tachycardia, rhythm irregularity, urine amount! 1 mL/kg/h, hypotension, impaired peripheral perfusion), skin and subcutaneous lesions (petechiae, sclerema), respiratory instability (apnea or tachypnea, increased oxygen demand, increased need for ventilation support), gastrointestinal (food intolerance, abdominal distension), non-specific (irritability lethargy, hypotension);
5. **positive culture for pathogens until 7 days before the suspicion of sepsis: LONS pathogens**, i.e., coagulase, negative staphylococci, _Staphylococcus aureus_, group B _Streptococcus_, _Enterococcus_ spp., _Escherichia coli_, _Klebsiella_ spp, _Serratia_ spp., _Enterobacter_ spp., _Pseudomonas_ spp., _Acinetobacter baumannii_, _Candida_ spp. ;
6. **value of C-reactive protein (CRP);
7. **value of procalcitonin (PCT);**
8. **metabolic acidosis (blood gas pH);**
9. **days with central venous catheter (CVC);**
10. **patient intubation**;
11. **HeRO score acquired every hour**. The authors found it interesting to include data related to the presence in NICU of patients with positive cultures for aggressive pathogens, notoriously responsible for late onset sepsis, both at the time of the suspicious episode and up to 7 days before. This is for the purpose of considering as a risk factor the microbiological data of the patient and more generally the pathogenic flora present in the NICU. One or more clinical cases have been extracted from patient data according to the manifestations of at least one of the following events that raised the suspicion of sepsis:  
1. the positivity of HeRO;
2. the presence of symptoms;
3. the positivity of the inflammation indexes. In particular, if the event was the positivity of the HeRO score, all analysed parameter values were referred to the next 24 h, whereas if the event was the presence of symptoms and/or the positivity of the inflammation indexes, all analysed parameters values were referred to the previous 24 h. In 17 patients out of 21, alerts were observed that raised the suspicion of sepsis for a total of 30 alerts (or clinical cases). In 10 clinical cases out of 30, sepsis diagnosis was then confirmed. The studied cohort also included four patients that neither presented any signs of sepsis, nor were affected by sepsis. Figure 1 reports the distribution of the studied clinical cases. \begin{table}
\begin{tabular}{c c} \hline \hline
**Population Characteristic** & **Distribution Median (SD)** \\ \hline Birth weight & 937.0 (288.6) g \\ Gestational age & 27.5 (2.4) weeks \\ Male percentage & 47.6\% \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Population characteristics. The HeRO duet is a medical device that supports medical personnel in diagnosis with high predictivity if it is used together with anamnestic and laboratory clinical findings. It allows intervening with antibiotic therapies also in correspondence with one of the first reported peaks, thus preventing short- and long-term complications associated with serious sepsis. In fact, as is well known in the literature, the first antibiotic administration, being always the most effective, would lead to a decisive intervention on the patient, if carried out in a timely manner [19]. The HeRO duet was designed to non-invasively predict neonatal sepsis and works by getting data from a generic device used to monitor vital functions. The HeRO duet detects the data concerning the ECG waveforms from the physiological monitor, which are subsequently transmitted in the form of an analogue signal via a cable connected to the AD2-DAD data acquisition device. The Drager C500 monitor(www.draeger.com) was used in this study.