Incidence of respiratory viruses in preterm infants submitted to mechanical ventilation

Amaç

 

1 .To verify the incidenee of infection by respiratory viruses in preterm infants submitted to mechanical ventilation. 2.To evaluate the clinical, laboratorial and radiological patterns of viral infections among hospitalized children in the Neonatal Intensive Care Unit (NICU) with respiratoty failure.

Yöntem

Seventy preterm infants were studied prospectively from November 2000 through July 2002. All neonates had the following protocol investigations: clinical, radiological and laboratorial data, including specific exams for respiratory viral pathogens: indirect immunofluorescence assay (IFA) with monoclonal antibodies and viral cultuıe from nasopharyngeal aspirates. The presence of respiratory viruses in children's nasopharyngeal was assessed at admission in the NICU and throughout the mechanical ventilation period. Blood culture was used for bacterial investigation.

Bulgular

Respiratory viruses were diagnosed in 20 preterm neonates (28.6%) with respiratory failure and that were submitted to mechanical ventilation. The most common admitting diagnose was hyaline membrane disease 18 (90.0%). Respiratory syncytial virus was detected in nine neonates (12.8%), Influenza A virus in eight (11.4%), Respiratory syncytial virus plus Influenza A virus in two (2.8%), and Influenza A virus plus Parainfluenza virus type 3 in one infant (1.4%). Most of the neonates with viral infection had the following characteristics: female 14 (70.0%), with average gestational age of 32.5 weeks (range 27.5-36.5 weeks) and with average birth weight of 1553 g (range 830-3050 g). The average age of hospital admission was 13 days of life (range 1-33 days). The main risk factors were: no breast feeding (p=0.022) and family history of respiratory infection (p=0.046). The most frequent clinical signs were: cyanosis in 17 cases (85.0%); fever in 10 (50.0%); rhinorrhea, wheezing and apnea in eight (40.0%); bradycardia in six (30.0%); and vomiting plus diarrhea in four neonates (20.0%). Eighteen neonates (90.0%) developed pneumonia during hospitalization while six infants (30.0%) presented sepsis. Respiratory viruses were associated to bacteria in six cases (30.0%). An alveolar infiltrate was present in 13 (72.2%), an interstitial infillrate in five (27.8%) and atelectasis in 11 (61.1%) of the 18 patients with pneumonia. The average duration of mechanical ventilation was 17 days (range 1-96 days). From 20 preterm neonates with viral infection, only one unfortunately died.

Sonuç
 

Although the majority of viral respiratory infections have a benign clinical course, some patients can present a serious clinical picture, mainly when the respiratory viruses involve preterm newborns. İt is important to emphasize the need for early etiological diagnosis of these infections in order to choose the appropriate therapeutics and control the spread of the viral pathogens within the neonatal units.