Pediatric research
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This study was designed to evaluate the effect of normothermic partial bypass, or venoarterial extracorporeal membrane oxygenation (ECMO), on cerebral autoregulation. Fourteen newborn lambs, 1-7 d of age, were randomized into two groups: control (ligation of right carotid artery and jugular vein without ECMO; n = 7) and ECMO (ligation with placement on routine venoarterial ECMO at 120-150 mL/kg/min; n = 7). After 1 h of ECMO or stabilization in controls, cerebral autoregulation was evaluated by lowering cerebral perfusion pressure (CPP) by increasing intracranial pressure through infusion of artificial cerebrospinal fluid into the lateral ventricle. ⋯ Cerebral oxygen consumption decreased from baseline (4.2 +/- 1.1 mL/100 g/min) to 4.0 +/- 0.7 and 3.2 +/- 1.3 mL/100 g/min at CPP of 39-25 and < 25 mm Hg, respectively, in the ECMO group. In the control group, cerebral oxygen consumption was unchanged from baseline (4.2 +/- 1.1 mL/100 g/min) until CPP was reduced to < 25 mm Hg (3.2 +/- 1.3 mL/100 g/min). When CBF autoregulation was altered, i.e. when total CBF decreased, right-left hemispheric CBF differences were noted in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Pain perception and effectiveness of the eutectic mixture of local anesthetics in children undergoing venipuncture.
The emulsion of lidocaine and prilocaine (EMLA) is effective in preventing the pain of venipuncture in children. It is therefore important to identify children who could benefit the most from EMLA. We studied the safety and feasibility of two methods of application of EMLA (patch and cream) in a randomized, open-label trial of EMLA patch versus EMLA cream in 160 children with chronic diseases undergoing venipuncture. ⋯ Children recently diagnosed had higher visual analogue scores than those with a long history of chronic disease. We concluded that EMLA patch and cream have a similar efficacy in children undergoing venipuncture. Young children recently diagnosed with chronic disease are most likely to benefit from EMLA.
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Transmission pulse oximetry is used for monitoring in many clinical settings. However, for fetal monitoring during labor and in situations with poor peripheral perfusion, transmission pulse oximetry cannot be used. Therefore, we developed a reflectance pulse oximeter, which uses the relative intensity changes of the reflected red and infrared light (red/infrared ratio) to measure the arterial oxygen saturation. ⋯ A calibration curve for the relationship between red/infrared ratio and arterial oxygen saturation was obtained from 53 measurements in four fetal lambs, by linear regression analysis [red/infrared = 4.088-(0.038. SaO2), r = 0.96]. In these experiments, the pulse oximeter showed a precision of 4.7% oxygen saturation around the calibration curve, with a 95% confidence interval of +/- 9.4%.
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We studied the distribution of systemic blood flow during venoarterial extracorporeal membrane oxygenation (ECMO) in newborn lambs. We used a three-compartment model that defined partitioning of blood flow to the heart, upper body (brachiocephalic trunk), and lower body (descending aorta). The method used concurrent left ventricular and arterial cannular injections of radiolabeled microspheres to calculate compartment flows and solve the system of equations that defined the partition model. ⋯ However, blood flow from the ECMO circuit was preferentially directed to the upper body. Coronary arterial and abdominal organ blood flow was predominantly derived from the left ventricle at both ECMO flow rates. Coronary arterial blood flow did not significantly change on ECMO (253 +/- 45 mL/min/100 g at 50 mL/min/kg ECMO flow; 246 +/- 50 mL/min/100 g at 100 mL/min/kg ECMO flow) compared to baseline (186 +/- 31 mL/min/100 g).(ABSTRACT TRUNCATED AT 250 WORDS)
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We assessed pulmonary function in 14 mechanically ventilated newborn very low birth weight infants with idiopathic respiratory distress syndrome by means of a face-out, volume displacement body plethysmograph and nitrogen washout analyses. Specially designed computer programs were used for calculations of lung volumes, ventilation, gas mixing efficiency, and mechanical parameters. ⋯ No correlations between positive end-expiratory pressure and mean airway pressure versus compliance, resistance, or FRC could be found. Neither could correlations be found between FRC and compliance or FRC and the calculated right to left shunt.