Biphasic Cuirass Ventilation
Biphasic Cuirass Ventilation
Biphasic Cuirass Ventilation
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External High Frequency Oscillation in Normal Subjects and in Patients with Acute<br />
Respiratory Failure<br />
Al-Saady NM, Fernando SS, Petros AJ, Cumin AR, Sidhu VS and Bennett ED<br />
Department of Medicine, St. George's Hospital Medical School, London<br />
External high Frequency oscillation was performed on 20 healthy volunteers using a cuirassbased<br />
system, the Hayek Oscillator. Five-min periods of oscillation were carried out on each subject at<br />
frequencies of !,2, 3, 4 and 5 Hz. Effective ventilation was measured in terms of the fall in alveolar partial<br />
pressure of carbon dioxide immediately after oscillation. The optimum frequency for oscillation<br />
was 1-3 Hz but most of the subjects were adequately ventilated over a wide range of frequencies. Thus, the<br />
Hayek Oscillator is capable of adequately ventilating normal subjects by means of chest wall oscillation.<br />
We also compared external high frequency oscillation with intermittent positive<br />
pressure ventilation in five patients with respiratory failure. Using the same<br />
inspired oxygen fraction, the external high frequency oscillation replaced<br />
intermittent positive pressure ventilation for a 30-min period. External high<br />
frequency oscillation improved oxygenation by 16% and reduced the arterial<br />
carbon dioxide by 6%. These preliminary findings suggest that normal subjects<br />
and intensive care unit patients can be adequately ventilated by means of external<br />
high frequency oscillation.<br />
Anaesthesia 50 (12): 103 -5, December 1995
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