Positional effects on lung mechanics of ventilated preterm infants with acute and chronic lung disease.

BACKGROUND: The role of prone position in preterm infants has not been completely clarified. We investigated prone versus supine posture-related changes in respiratory system resistance (Rrs) and reactance (Xrs) measured by the Forced Oscillation Technique (FOT) in mechanically ventilated preterm newborns. METHODS: Patients were studied in the supine versus prone positions in random order. Oxygen saturation, transcutaneous partial pressure of oxygen (ptcO2 ), carbon dioxide (ptcCO2 ), Rrs and Xrs were measured in each position. RESULTS: Nine patients with respiratory distress syndrome (RDS) and nine with evolving broncho-pulmonary dysplasia (BPD) were studied. Rrs was, on average, 9.8 (1.3, 18.3 as 95%CI) cmH2 O*s/l lower in the prone compared to the supine position (P = 0.02), while no differences in Xrs, ptcO2 , ptcCO2 , and breathing pattern were observed between postures. Only patients with evolving BPD showed a significant reduction of Rrs from 69.0 ± 27.4 to 53.0 ± 16.7 cmH2 O*s/l, P = 0.01. No significant correlations were found between changes in lung mechanics and ptcO2 , ptcCO2 , or breathing pattern. CONCLUSIONS: On short-term basis, prone positioning does not offer significant advantages in lung mechanics in mechanically ventilated infants with RDS, while it is associated with lower Rrs values in patients with evolving BPD.

Relationship between respiratory impedance and positive end-expiratory pressure in mechanically ventilated neonates.

PURPOSE: To evaluate the feasibility of forced oscillation technique (FOT) measurements at the bedside and to describe the relationship between positive end-expiration pressure (PEEP) and lung mechanics in different groups of ventilated infants. METHODS: Twenty-eight infants were studied: 5 controls, 16 newborns with respiratory distress syndrome (RDS) and 7 chronically ventilated newborns that developed bronchopulmonary dysplasia. An incremental/decremental PEEP trial was performed by changing PEEP in 1-min steps of 1 cmH(2)O between 2 and 10 cmH(2)O. Forced oscillations at 5 Hz were superimposed on the ventilator waveform. Pressure and flow, measured at the inlet of the ETT, were used to compute resistance (Rrs) and reactance (Xrs). RESULTS: In controls Rrs and Xrs were on average 41 ± 21 and -22 ± 6 cmH(2)O s/l respectively and were almost unaffected by PEEP. RDS infants presented similar Rrs (48 ± 25 cmH(2)O s/l) and reduced Xrs (-71 ± 19 cmH(2)O s/l) at the beginning of the trial. Two behaviours were observed as PEEP was increased: in extremely low birth weight infants Xrs decreased with PEEP with marked hysteresis; in very low and low birth weight infants Xrs and Rrs were less PEEP dependent. Chronically ventilated infants had very high Rrs and very negative Xrs values at very low PEEPs (121 ± 41 and -95 ± 13 cmH(2)O s/l at PEEP = 2 cmH(2)O) that markedly changed as PEEP exceeded 3-4 cmH(2)O. CONCLUSIONS: Rrs and Xrs measurement in preterm newborns is feasible, and data are representative of the lung mechanics and very sensitive to its changes with PEEP, making FOT a promising technique for the non-invasive bedside titration of mechanical ventilation in preterm newborns.

[Contact dermatitis of the hands in housewives: preliminary data of a multicenter study]. / Indagine sulla dermatite da contatto delle mani delle casalinghe: dati preliminari di uno studio multicentrico.

The preliminary results of a survey carried out by the Institutes of Dermatology of Bari and Florence Universities and by the Clinica del Lavoro of Milan University are analyzed. The survey, whose aim is to identify the causes of contact dermatitis on housewives' hands and whose conclusions are forecasted for June 1990, will examine 1,650 female people, 1,050 of which are ill and 600 are case-controls. The results of the first 617 cases (514 ill and 103 case-controls) are reported. The anamnesis has shown that the hands (in 488 cases) are the most affected part of the body, that the most frequent symptoms are itch and burning sensation (in 410 cases), and that cosmetics, followed by detergents and softeners, are considered by the patients among the products more responsible for these symptoms. The allergic tests, even if with a different percentage of incidence, have shown metals (above all nickel), rubber additives and resins as the main aptens. Another survey, also in progress, concerning the search of metals in detergents and in washing waters for pollution caused by abrasives, pots, Inox sinks, pipes and tabs of the water system, is reported.

[Dermatopathies in the domestic worker: the Lombard experience]. / Dermopatie nel lavoro domestico: l'esperienza lombarda.

In order to identify the etiopathogenesis of cutaneous diseases in housewives, a questionnaire was made, and the gathered data are here described. 1,824 people have answered this questionnaire: 1,007 have reported lesions with a suspicious immunological pathogenesis. The commercial products which were reported as a cause of the dermatitis have been 834. In a group of 142 housewives (86 with allergic contact dermatitis and 56 with irritative contact dermatitis), the allergic sensitizations to the chemicals in the detergents were tested. 21% of the cases had positive cutaneous reactions for nickel salts and 8.4% for chromium salts. The analysis in atomic absorption method of these metals in 34 commercial products has shown their presence in almost all the samples. Hypothesis are formulated to find the source of these polluting substances. The aims and the methods of a investigation carried out on 1.800 housewives, who are going to be controlled in order to estimate the prevalence, the clinical kinds and the etiopathogenesis of dermatitis related to house work, are described. The study will be carried out at the Occupational Health Institute "Clinica del Lavoro L. Devoto" of Milan and at the Dermatological Departments of the Universities of Bari and Florence.