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Background and aims: Aortic pulse wave velocity (aPWV) estimates aortic stiffness and predicts cardiovascular mortality risk in adults. Since children with kidney disease are at high risk for cardiovasular mortality later in life, it would be important to detect advanced arterial stiffening early. There are different ways to assess aPWV. This study compares aPWV values of young individuals measured by applanation tonometry (SphygmoCor) and with a new oscillometric device (Vicorder). Methods: aPWV in 131 healthy children (age 6-18 years) was measured 1. by sequential tonometry and 2. by oscillometry in a synchronic manner. SphygmoCor aPWV was calculated with distance 1 (dist.1) [=(Suprasternal notch(SSN) to Umbilicus(Umb)) + (Umb to A.fem.) - (SSN to A.car.)]. For Vicorder 3 additional distances were measured and used: dist.2 [=(SSN to Umb) + (Umb to A.fem.)]; dist.3 [=SSN to A.fem.]; dist.4 [=(SSN to A.fem.) - (SSN to A.car.)]. Results: Mean SphygmoCor aPWV was 4.9±0.6 m/s. Vicorder aPWV were 4.6±0.6 m/s (dist.1; r=0.46 for correlation with Sphygmocor; p< 0.0001); 5.3±0.7 m/s (dist.2; r=0.44; p< 0.0001); 5.2±0.7 m/s (dist.3; r=0.45; p< 0.0001); 4.6±0.6 m/s (dist.4; r=0.46; p< 0.0001). Using dist.1, the lowest deviation was seen (11.3±8.1%). Conclusions: The variability between both methods is well acceptable using dist.1. Since the Vicorder is easier to handle, needs less operator training and measurements are done more quickly, it seems the appropriate device for larger cohort studies in children.

A new procedure for real time, nonradiographic determination of endotracheal tube position with a magnetic field interference sensing technique was evaluated in cadavers. Each prototype tube incorporates a magnetically detectable marker at a specific distance from its distal tip, which varies with tube size. Transcutaneous determination of tube position is accomplished with a portable instrument that emits visual and aural signals of intensity proportionate to the alignment and proximity of the instrument sensing probe with the tube's magnetic marker. In the preclinical studies the magnetic marker was positioned so that the maximum signal intensities were obtained when the instrument probe was located at the upper edge of the suprasternal notch. Studies were carried out in 25 cadavers adhering to the protocol utilizing six tube sizes. In each case radiographic analysis confirmed distal tip placement to be above the carina, estimated at the 4th/5th vertebral space, and within the middle third of the trachea below the suprasternal notch. We conclude that this method will reduce the need for X-ray confirmation of tracheal tube position in pediatrio patients and that testing in living, intubated infants is warranted.

Shoulder umbilical length (SUL) &/or total body length (TBL) have been been traditional parameters used to estimate internal umbilical catheter (cath) length. To improve these estimates & to act quickly in emergencies when traditional measurements may be difficult to measure or calculate from nomograms, the reliable weight variable in predicting internal length was used. 35 Sick NB with inserted UA lines (using Dunn's Graph of SUL) & cath tips between T6 & T10 vertebra, by (x-rays) were studied. Independent variables measured on each patient included SUL, TBC, birth weight, distance between suprasternal notch & symphisis pubis, total cath length before insertion & external length of cath after insertion. Dependent variable was calculated portion of cath within the patient.

The combination of 2-dimensional real-time and pulsed Doppler echocardiography provides a noninvasive method of measuring blood flow and has been used to study blood flow at the lower thoracic level of the descending aorta (DA) in the human fetus. Using these techniques, we evaluated the proportion of cardiac output distributed through the DA in 13 term newborn infants (mean±SEM BW 3551±95 g, GA 40.1±0.3 w). Blood flow velocity was measured using a 3.5 MHz, range gated, pulsed Doppler velocity meter with the transducer positioned in the suprasternal notch. Blood flow in the ascending aorta (AA) was measured at the aortic root level and descending flow below the isthmus. The internal diameter of the AA was assessed at the level of the aortic valve using M-mode echocardiography and the diameter of the DA in the posterior atrioventricular groove with the use of the 2-D long axis view. Blood flow in the AA was 789±42 ml/min and in the DA 499±26 ml/min indicating that 63.5% of the left ventricular output is distributed through the DA. The mean blood flow velocity was comparable at both sites, whereas the mean diameter of the DA was 19% smaller than the diameter of the AA. In healthy term newborn infants approx. 2/3 of cardiac output is directed to the DA and 1/3 to brachial and carotid arteries. The changes in aortic blood flow are correlated with the changes in aortic diameter.

In order to meet metabolic demands, oxygen delivery(DO2)must be sufficient. However, in children with acute respiratory failure (ARF), DO2 is often partially estimated because cardiac output(CO) is rarely taken into account. This work reports the effects of mechanical ventilation with PEEP (CPPV) on DO2. Methods : 7 newborns (GA : 34±2wks) with hyaline membrane disease and 3 children (5-10mos-12yrs) with ARF were evaluated. SaO2 was measured using Nellcor (tcSO2). The mean ascending aortic velocity was measured from suprasternal notch using a Pulsed-Doppler Vingmed SD-100 while the aortic diameter was measured at the aortic leaflets level. CO was automatically measured and averaged every 2.5 sec. Whithout modifying other settings, PEEP was stepwise increased and Paw, tcPO2, tcSO2 and CO were measured. Thus, DO2 may be non-invasively measured in children. The stepwise increments in PEEP and Paw induced both an increase in arterial oxygenation and decrease in CO, leading to the concept of using the minimal effective or “optimal” PEEP in ARF.

The initial or continuing patency of systemic-to-pulmonary artery anastomoses is often difficult to establish clinically. A continuous murmur may or may not be present, especially immediately postoperatively, or it may be masked. Increase in PaO2 may be helpful, but occasionally aortography is necessary to confirm patency. The purpose of this study was to use RGPD to identify the flow characteristics of systemic-pulmonary artery shunts. RGPD is a noninvasive bedside technique which allows evaluation of flow by placing a Doppler sample beam within an echocardio-graphically defined cavity. With the transducer placed in the suprasternal notch, the sample Doppler beam was placed within the right pulmonary artery (RPA). Flow characteristics were described by both a time interval histogram (TIH) and by an audible signal (AS). Thirty-eight children were studied by RGPD. Ten normal children had neither systolic nor diastolic RPA turbulence. Nineteen subjects with valvar pulmonic stenosis had RPA systolic turbulence by TIH and AS. Nine children (age 1 day-10 years) had Blalock-Taussig (4) or Waterston-Cooley (5) shunts. Seven were evaluated within 1 week postoperation. Shunt patency was confirmed by autopsy (2), catheterization (2) or by Pa02 rise (5). Suprasternal RGPD showed RPA systolic and diastolic turbulent flow in 9 of 9 by TIH and AS; in 6, a shunt murmur was not audible at the time of RGPD. RGPD is a useful noninvasive bedside test which effectively confirms surgical shunt patency.