ABSTRACT
<p><b>OBJECTIVE</b>To study the characteristics and role of dynamic pressure-volume curve (P-V curve) in neonatal mechanical ventilation.</p><p><b>METHODS</b>A dynamic P-V curve was automatically drawn by the Stephanie ventilator. The slope rate of dynamic P-V curve was measured in 25 neonates who received mechanical ventilation 1, 24, 48 and 72 hrs after ventilation and before weaning from ventilation. Minute-ventilation (MV), mean airway pressure (Pmean), and fraction of inspired oxygen (FiO2) were recorded. The patterns of dynamic P-V curve during abnormal ventilation (resistance to ventilator, part or complete airway obstruction, airway leaking and tracheal catheter exodus) were observed.</p><p><b>RESULTS</b>With the improvement of pulmonary disease, the slope rate of P-V curve and MV increased, Pmean and FiO2 decreased, and the P-V curve shifted to the volume axle. The slope rate of curve 48 and 72 hrs after ventilation and before weaning from ventilation (1.05+/-0.48, 1.10+/-0.42 and 1.13+/-0.37 mL/cmH2O respectively) increased significantly compared with that 1 hr after ventilation (0.76+/-0.53 mL/cmH2O) (p<0.05 or 0.01). Abnormal ventilation led to abnormal appearance of dynamic P-V curve.</p><p><b>CONCLUSIONS</b>The increasing slope rate of dynamic P-V curve and the curve shifting to volume axle in neonatal mechanical ventilation may be associated with the improvement of pulmonary disease. The appearance changes of the curve may be of value in the assessment of abnormal ventilation.</p>
Subject(s)
Female , Humans , Infant, Newborn , Male , Lung , Lung Diseases , Respiration, Artificial , Respiratory MechanicsABSTRACT
<p><b>OBJECTIVE</b>To study the value of apolipoprotein H (apoH) gene expression in peripheral blood mononuclear cell (PBMC) and urinary N-Acetyl-beta-D-Glucosaminidase (NAG) and retinal-binding protein (RBP) in the early diagnosis of renal function damage in neonates.</p><p><b>METHODS</b>Sixty sick neonates who renal function damage probably occurred were enrolled. The blood and urinary samples were collected twice within 48 hrs following admission, with an interval of 12-24 hrs. Expression of apoH gene in PBMC was determined with RT-PCR. The levels of blood urea nitrogen (BUN) and creatinine, and urinary activities of NAG and RBP were measured with enzymatic reaction.</p><p><b>RESULTS</b>The abnormal rates of blood apoH and urinary NAG and RBP were 73.3%, 83.3% and 76.7%, respectively in the first detection. The second detection for blood apoH and urinary NAG and RBP showed abnormal rates of 70.0%, 66.7% and 76.7%, respectively. There were no significant differences in the abnormal rates between the three markers either in the first or the second detection (P>0.05). Beside there were no significant significances in the abnormal rates between urinary NAG and blood BUN in the second detection, the abnormal rates of blood apoH and urinary NAG and RBP in both detections were significantly higher than those of BUN or creatinine (P<0.01 or 0.05).</p><p><b>CONCLUSIONS</b>There are identical values of blood apoH gene expression and urinary NAG and RBP in the early diagnosis of renal function damage in neonates. The above three markers are more sensitive to early renal function damage than blood BUN and creatinine.</p>