الفهرس 
MECHANICAL VENTILATIONOnly 14 pages are availabe for public view
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Abstract
Mechanical ventilation is one of the most common therapies in the newborn intensive care unit (NICU), and is associated with increased morbidity and mortality. The effects of positive pressure ventilation especially the HFOV on hemodynamic parameters are known to be complex and contradictory.
This aim of the present study was to compare the hemodynamic effects of the two modalities of assisted ventilation CMV and HFOV at the same mean airway pressure, assessed by Targeted Neonatal Echocardiography.
This randomized control study was conducted from January 2013 till May 2015 in the neonatal intensive care unit (NICU) of Pediatric Hospital, Ain Shams University, Cairo, Egypt. 58 neonates were included in our study, 29 on conventional mechanical ventilation and 29 on high frequency oscillatory ventilation.
Neonates included were those requiring ongoing intensive care and mechanical ventilation, whether preterms or full terms. Patients with Patent Ductus Arteriosus (PDA) were also included. Both groups were of matched gestational age, postnatal age, gender and surfactant administration.
Patients with major congenital cardiac malformations, who were early transfered to another unit, failed to get a parental consent or had no matched patient in the other group were excluded from our study. Patients who were shocked, if a preterm requires adrenaline infusion or if a term requires more than 2 boluses were also excluded from our study.
All patients were subjected to the following:
Full medical history
Thorough clinical examination
Laboratory investigations, CBG, CBC, CRP and Blood culture
Chest X-ray
Transcranial ultrasound
Targeted Neonatal Echocardiography
The studied neonates included 34 males and 24 females, 32 preterm and 26 full term. 10 of our patients were in the first 2 days of life while the rest were older than 2 days of life. 30 were born by spontaneous vaginal delivery and 28 by cesarean section.
We found that most of our patients were ventilated due to congenital pneumonia followed by post operative recovery and RDS. 29% of the patients had sepsis evidenced by positive blood culture, thrombocytopenia and elevated CRP level.
The patients were divided into 2 equal comparable groups, one on CMV and the other on HFOV. There was a significant decrease of pCO2 in neonates on HFOV versus those on CMV.
Cranial ultrasound revealed 11 of the enrolled patients had intracranial hemorrhage. There was a non-significant difference between CMV and HFOV as regards the presence of intracranial hemorrhage.
TNE results showed highly significant positive correlation between the LVEDD and weight. Most importantly, TNE results showed no significant differences between CMV and HFOV when the same PAW was applied. We also divided patients according to their gestational age, postnatal age, presence of sepsis, presence of PDA and surfactant replacement therapy if received into groups. Each group was furtherly divided according to the mode of ventilation and compared according to TNE parameters. There was no statistical significant difference between the two modes of ventilation, indicating no hemodynamic adverse effect of HFOV when compared to CMV on same PAW.
Furthermore, we investigated 11 neonates, each of them had two echocardiographic studies by the same investigator during CMV and HFOV when same PAW was applied in less than 4 hours. Echocardiographic studies were performed immediately before the patients were switched from CMV to HFOV and then repeated at a median time of 1 hr (range, 0.5-1.5) after initiating HFO. There was no statistical significant difference as regards the TNE parameters between the 2 modes of ventilation.
In our study, eight patients were diagnosed RDS. 75% of them received surfactant. We made a comparison between those who received surfactant once and those who did not. We found that there was a significant decrease in the PAW used in both groups. There was a significant difference between these 2 groups as regards the TNE parameters (pulmonary artery pressure, RVO, Ejection fraction and shortening fraction).
In addition, we compared patients with patent ductus arteriosus to those who had an obliterated ductus. We found that SVC flow, LVO, RVO, pulmonary artery pressure was higher in patients with a PDA than in those with obliterated ductus.In conclusion, in all our preterm and full term ventilated neonates, we found no significant hemodynamic effect of HFOV rather than CMV when used with the same mean airway pressure.
Wide spread use of high frequency ventilation in neonates is recommended whenever needed since it has no significant hemodynamic effect rather than conventional mechanical ventilation when used on the same mean airway pressure