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Biomedical subjects

Steven L Olsen

Publications and source records attributed to Steven L Olsen.

4 recordsLinked to original sources
PubMed2003

Exhaled nitric oxide and tracheal endothelin-1 in preterm infants with and without RDS.

We measured exhaled nitric oxide and tracheal aspirate endothelin-1 to determine relationships between these substances and alterations in pulmonary gas exchange during respiratory distress syndrome (RDS) in comparison to those obtained from control preterm infants without RDS. Eight infants with RDS had measurements made at 24 hr and again at 48-72 hr. Eight control infants were studied once at 24-48 hr of life. Exhaled gas was analyzed on-line, and minute excretion of NO (V(NO)) was calculated. ET-1 was determined by immunoassay. Median V(NO) at 24 hr in RDS was 0.405 nl/min/kg (range, 0.30 -0.79), which subsequently declined by 48-72 hr to 0.166 nl/min/kg (P < 0.01). The V(NO) in RDS infants was significantly higher than time-matched V(NO) in controls, with a median of 0.099 nl/min/kg (range, 0.03-0.27; P < 0.001). ET-1 was not correlated with initial V(NO) in the RDS or control patients. In conclusion, in RDS, V(NO) decreases as gas exchange improves. ET-1 is detectable in tracheal aspirate samples in both groups of infants.

Body Fluids↗
PubMed2002

Platelet endothelial cell adhesion molecule-1 and capillary loading in premature infants with and without chronic lung disease.

It was our objective to quantify platelet endothelial cell adhesion molecule-1 (PECAM-1) by immunohistochemistry in control infants of 22-50 weeks postconceptual age, and to correlate it with varying degrees of neonatal chronic lung disease (CLD). We tested the hypothesis that the density of PECAM-1 staining will positively correlate with increasing gestational age (GA) and the inflammatory process in CLD. A library of postmortem lung tissue of infants receiving ventilator care was accessed. The population consisted of 35 control infants exposed briefly to oxygen and positive pressure ventilation, and 31 infants who were 23-30 weeks GA with mild to severe CLD. A monoclonal anti-human PECAM-1 antibody was used to stain 5-microm paraffin sections. The slides were viewed at a magnification of x 40 by a blinded examiner. Twenty consecutive fields from standardly expanded tissue samples were viewed, and the volume density of PECAM-1 (V(V PECAM)) per parenchyma was measured, using point counting. In addition, 1-microm sections from 15 controls and 5 infants with CLD were stained with Toluidine blue and viewed under oil at a magnification of x 100, and the volume density of capillaries (V(V CAP)) and capillary load (CL) were calculated. The V(V PECAM) increased significantly with GA in controls (r = 0.72, P < 0.001). There was no relationship between V(V PECAM) and severity of CLD. Both V(V CAP) and CL increased significantly with GA (r = 0.93, P < 0.001; r = 0.94, P < 0.001, respectively). The infants with CLD had a normal or increased V(V CAP) and CL compared to controls. In summary, V(V PECAM), V(V CAP), and CL increased significantly with gestational age in control infants, but the postconceptional age range in CLD infants was too short to determine whether the V(V PECAM) changed. Infants with CLD had normal or increased V(V CAP) and CL compared to controls. The PECAM-1 immunostain does not appear to be a sensitive method for assessing capillary density in infants with CLD. These findings of normal or increased capillary load may represent a vascular adaptation for the lack of secondary septation and decreased surface area in CLD.

Age Factors↗
PubMed2002

Crossover trial comparing pressure support with synchronized intermittent mandatory ventilation.

OBJECTIVE: To compare pressure support ventilation (PSV) with volume guarantee (VG) to synchronized intermittent mandatory ventilation (SIMV) in infants with respiratory distress syndrome (RDS). STUDY DESIGN: A randomized, crossover study design was used. We enrolled 14 infants [BW (mean+/-SD) 2.5+/-0.7 kg, GA 34+/-2 weeks, age 49+/-26 hours]. Subjects received 4 hours of each mode of ventilation, with the first mode selected randomly. End expiratory volume (EEV) was measured during both ventilatory modes. RESULTS: Minute ventilation was greater with PSV+VG than with SIMV (p=0.012). This occurred despite no difference in p(a)CO(2). Mean airway pressure was higher during PSV+VG (p=0.023). There was no difference in the arterial/alveolar oxygen tension (a/A) ratio or in the specific dynamic compliance (sCdyn). CONCLUSION: Because of an increase in V(E) with PSV+VG, and no difference in the a/A ratio or sCdyn, we do not recommend the routine use of PSV+VG for this population.

Carbon Dioxide↗