The proper tidal volume target using volume guarantee ventilation in the course of neonatal respiratory distress syndrome: a crucial endpoint.

Volume guarantee ventilation (VGV) is an optional ventilation mode which has become the most widely and extensively studied in the last 10 years in premature infants. Nonetheless, theoretical expected endpoints are intriguing and even though VGV has not yet become 'the' standard ventilation mode, a great deal of information has been acquired and stored. In our experience, VGV during the course of respiratory distress syndrome is useful and can be considered a standard ventilation mode. Weaning occurs in real time as described earlier, and synchronized intermittent positive pressure ventilation and pressure support ventilation (PSV) seem to be the preferred combined modes. Management during the acute phase requires more care since several sudden changes take place in both the lung mechanics and clinical behavior. The software is designed to protect the lung, and subsequently, sudden changes in lung compliance following iatrogenic procedures such as surfactant administration are powerfully counteracted. VGV has been extensively studied and the proposed algorithm has been found to function as planned. Although the 'superiority' of one method over another cannot be demonstrated, the use of new technologies require 'a staff learning curve' and homogeneity of treatment, while at the same time other factors, such as patient heterogeneity or illness phase, should be taken into due account.

Volume targeted ventilation (volume guarantee) in the weaning phase of premature newborn infants.

OBJECTIVE: Several options are currently available in neonatal mechanical ventilation: complete breathing synchronization (patient triggered ventilation, synchronized intermittent positive pressure ventilation--SIPPV); positive pressure flow-cycled ventilation (pressure support ventilation, PSV); and volume targeted positive pressure ventilation (volume guarantee, VG). The software algorithm for the guarantee volume attempts to deliver a tidal volume (Vt) as close as possible to what has been selected by the clinician as the target volume. Main objectives of the present study were to compare patient-ventilator interactions and Vt variability in premature infants recovering from respiratory distress syndrome (RDS) who were weaned by various ventilator modes (SIMV/PSV + VG/SIPPV + VG and SIMV + VG). METHODS: This was a short-term crossover trial in which each infant served as his/her own control. Ten premature infants born before the 32nd week of gestation in the recovery phase of RDS were enrolled in the study. All recruited infants started ventilation with SIPPV and in the weaning phase were switched to synchronized intermittent mandatory ventilation (SIMV). Baseline data were collected during an initial 20-min period of monitoring with the infant receiving SIMV alone, then they were switched to SIPPV + VG for a 20-min period and then switched back to SIMV for 15 min. Next, they were switched to PSV + VG for the study period and switched back to SIMV for a further 15 min. Finally, they were switched to SIMV + VG and, at the end of monitoring, they were again switched back to SIMV alone. RESULTS: Each mode combined with VG discharged comparable Vts, which were very close to the target volume. Among the VG-combined modes, mean variability of Vt from preset Vt was significantly different. Variability from the target value was significantly lower in SIPPV and PSV modes than in SIMV (P < 0.0001 and P < 0.04 respectively). SIPPV + VG showed greater stability of Vt, fewer large breaths, lower respiratory rate, and allowed for lower peak inspiratory pressure than what was delivered by the ventilator during other modes. No significant changes in blood gases were observed after each of the study periods. CONCLUSIONS: With regards to the weaning phase, among combined modes, both of the ones in which every breath is supported (SIPPV/PSV) are likely to be the most effective in the delivery of stable Vt using a low working pressure, thus, at least in the short term, likely more gentle for the neonatal lung. In summary, we can suggest that the VG option, when combined with traditional, patient triggered ventilation, adheres very closely to the proposed theoretical algorithm, achieving highly effective ventilation.

Diagnostic protocol for lymphoscintigraphy in newborns.

The purpose of this methods paper is to offer pediatricians and nuclear medicine physicians a diagnostic protocol for performing lymphoscintigraphy in newborns that may be useful for enhancing diagnosis and management of newborns with congenital lymphatic abnormalities. Indications for lymphoscintigraphy, choice of tracer, optimal dose, routes of administration, methods of data acquisition, timing, and interpretation of results for newborns are presented and discussed.

A randomised control study comparing the Infant Flow Driver with nasal continuous positive airway pressure in preterm infants.

OBJECTIVE: To compare the effectiveness of the Infant Flow Driver (IFD) with single prong nasal continuous positive airway pressure (nCPAP) in preterm neonates affected by respiratory distress syndrome. DESIGN: Randomised controlled study. PATIENTS: Between September 1997 and March 1999, 36 preterm infants who were eligible for CPAP treatment were randomly selected for either nCPAP or IFD and studied prospectively for changes in oxygen requirement and/or respiratory rate. The requirement for mechanical ventilation, complications of treatment, and effects on mid-term outcome were also evaluated. RESULTS: Use of the IFD had a significantly beneficial effect on both oxygen requirement and respiratory rate (p < 0.0001) when compared with nCPAP. Moreover, O(2) requirement and respiratory rate were significantly decreased by four hours (p < 0.001 and p < 0.03 respectively). The probability of remaining supplementary oxygen free over the first 48 hours of treatment was significantly higher in patients treated with the IFD than with nCPAP (p < 0.02). IFD treated patients had a higher success (weaning) rate (94% v 72 %) and shorter duration of treatment (49.3 (31) v 56 (29.7) hours respectively; mean (SD)), although the difference was not significant. CONCLUSIONS: IFD appears to be a feasible device for managing respiratory distress syndrome in preterm infants, and benefits may be had with regard to oxygen requirement and respiratory rate when compared with nCPAP. The trend towards reduced requirement for mechanical ventilation, shorter clinical recovery time, and shorter duration of treatment requires further evaluation in a multicentre randomised clinical trial.

[2,3 diphosphoglycerate in preterm newborns]. / 2,3 difosfoglicerato nel neonato pretermine.

BACKGROUND: It has been largely shown that during the first month of life, in the preterm neonate Hb levels and Hct percentages rapidly decrease, high HbF concentration persists and a high oxygen affinity occurs. Data are needed to establish the level at which 2,3 dyphosphoglycerate (2,3 DPG) interacts with the regulation of oxygen affinity. SUBJECTS AND METHODS: 24 samples, from eight uncomplicated preterm newborns (34.1 +/- 1.83 GW, 1869 +/- +/- 291 BW) obtained at the same time as those required for the clinical management of the infants, were collected on the 2nd, 7th and 14th day of life. Blood gases, total hemoglobin and hematocrit were obtained from 0.3 ml arterialised capillary blood. Assays of 2,3 DPG were made separately on 0.4 ml venous blood. RESULTS: As expected tHb concentration and Hct percentages significantly decreased from day 2 to day 14 in all eight cases. On the contrary 2,3 DPG and p50 values remained stable. Subsequently throughout the study period all neonates had an increased 2,3 DPG/Hb ratio that was significantly related with p50 at standard conditions (p < 0.05). CONCLUSIONS: Stable 2,3 DPG concentrations during all study period have been detected. The subsequent significant increased 2.3 DPG/Hb, ratio related to increased p50 values, could have a key role in a physiological mechanism aimed to ensure adequate oxygen delivery to the tissues and to counteract the higher oxygen affinity of fetal hemoglobin. A wider sample is needed to validate this hypothesis.

[Nosologic evaluation of Noonan syndrome and description of nine cases]. / Inquadramento nosologico della sindrome di Noonan e descrizione di nove casi.

Noonan syndrome was first described over 20 years ago by Noonan and Ehmke. They defined a specific group of nine patients with valvular pulmonary stenosis who, in addition, had short stature, mild mental retardation, hypertelorism and unusual facies. The incidence of Noonan syndrome has been estimated to be between 1 in 1000 and 1 in 2500 live births. The primary biochemical defect in Noonan's syndrome is unknown. We analyzed 9 patients (5 males and 4 females) in an age range of 6 months to 10 years and 3 months with Noonan syndrome. Patients were diagnosed as having the syndrome if they had characteristic facies and a normal karyotype, plus one of the following signs: cardiac defects, short stature or undescended testes. All patients have ocular anomalies (epicanthal folds, ptosis of eyelids, hypertelorism, downslanting palpebral fissures and ocular proptosis). Congenital heart malformations are present in 8 patients and the more frequent cardiopath is pulmonary valve stenosis due to a dysplastic or thickened valve. Short stature is present in 6 patients and 3 of them are actually on treatment with rhGH. A moderate-mild mental retardation is present in 6 patients. Case n. 9 had a syringomyelia and tethered cord. These malformations are rarely reported in Noonan's syndrome.

[Seckel's syndrome]. / La sindrome di Seckel.

The case of a girl with Seckel syndrome, born of an epileptic mother who was taking anticonvulsant drugs, is reported. The patient, admitted to our clinic for short stature, presented some signs of Seckel syndrome: microcephaly, a "bird headed" profile with receding chin and forehead and large beaked nose. Microcephaly and a low birth weight are present in Seckel syndrome, but also in the newborn of epileptic mothers who received anticonvulsive drugs. In the present paper the Authors questioned if the described syndrome was caused by the use of antiepileptic drugs during pregnancy, or epilepsy of the mother, or if it was casual.