Effects of positive and negative pressure ventilation on cerebral blood volume of newborn infants.
The effects of intermittent positive airway and continuous negative extrathoracic pressure ventilation on cerebral blood volume in preterm infants were studied using near infrared spectroscopy. In 12 infants continuous negative extrathoracic pressure caused a median decrease in cerebral blood volume of 0.14 ml/100 ml brain (95% confidence intervals (CI) 0.035-0.280) compared with no respiratory support. Oxygenated and deoxygenated haemoglobin also decreased, implying increased venous drainage as the main effect. In 17 infants intermittent positive pressure ventilation also caused a median reduction in cerebral blood volume of 0.06 ml/100 ml brain (95% CI 0.010-0.115) compared with endotracheal positive airway pressure. Deoxygenated haemoglobin increased by 0.07 ml/100 ml brain (95% CI 0.010-0.100) while oxygenated haemoglobin decreased by 0.10 ml/100 ml brain (95% CI 0.005-0.175). The increase in deoxygenated haemoglobin implies decreased venous drainage and the decrease in oxygenated haemoglobin implies that other factors may also be significant. Heart rate, blood pressure and oxygen saturation were monitored continuously and remained stable.
Palmer
K S
KS
Academic Department of Paediatrics, School of Postgraduate Medicine and Biological Sciences, Keele University, North Staffordshire Hospital, Stoke-on-Trent, UK.
Spencer
S A
SA
Wickramasinghe
Y A
YA
Wright
T
T
Southall
D P
DP
Rolfe
P
P
D001784:Blood Gas Analysis; D001810:Blood Volume / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D007385:Intermittent Positive-Pressure Ventilation; D010108:Oxyhemoglobins / Q000032:analysis; D012127:Respiratory Distress Syndrome, Newborn / Q000097:blood / Q000503:physiopathology* / Q000628:therapy; D013055:Spectrophotometry, Infrared; D013997:Time Factors; D015919:Ventilators, Negative-Pressure
D010108:Oxyhemoglobins