Flow Meter Block for Boyles Anaesthetic Machine - 1960s
Date of manufacture:
This flow meter block from the 1960's has no emergency oxygen facility. That has been moved to the distal end of the manifold so that oxygen will still be available if there had been some leak or disconnection in the chain of vaporisers. Later, emergency oxygen would be delivered to the anaesthetic gas outlet, wherever that was located. The flows are oxygen 0 - 5 L/min, carbon dioxide, 0 - 2 L/min., Cyclopropane 0 - 750 ml/min and nitrous oxide 0 - 10 L/min. The carbon dioxide would have been used to assist ether inductions that were still practiced on patients with full stomachs, and to encourage the previously hyperventilated patients to breathe. Note that the oxygen flow is insufficient to deliver 100% oxygen to an adult in a non-rebreathing circuit.