THE HUMPHREY ADE SYSTEM: EVALUATION IN PAEDIATRIC USE

The Humphrey ADE single lever parallel form breathing system was evaluated in 17 children whose lungs were ventilated mechanically, mean age 28 (range 9-58) months, weight 13.3 (8.3-18.0) kg and in 10 spontaneously breathing children, age 50.7 (18-99) months and weight 17.5 (10.9-24.3) kg. During controlled ventilation in the E mode, the ADE behaved in a manner similar to the Jackson-Rees modification of Ayre's T-piece with the fresh gas flows (FGF) set either according to weight or at a standard 3 litre min-1. After 5 min hand ventilation in the A mode with FGF 3 liter min-1 the mean end-tidal partial pressure of carbon dioxide was 5.3 (SD 0.8) kPa (range 4.1-7.7 kPa). Whilst breathing spontaneously in the A mode, no patient experienced rebreathing at FGF 3 litre min-1; rebreathing started at 124 (31.6) ml kg-1 min-1. The ADE circuit performed satisfactorily in all three modes. During controlled ventilation in the E mode, FGF should be adjusted according to the standard formulae recommended for the T-piece circuit. During hand ventilation in the A mode, an FGF greater than 3 litre min-1 should be used.