Original communication| Volume 69, ISSUE 2, P309-313, February 1971

An inexpensive bedside analogue computer for measuring respiratory work and certain other parameters

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      We have constructed a small inexpensive bedside computer that measures: (1) pulmonary power, (2) pulmonary minute work, (3) respiratory airflow, (4) minute volume, (5) intrapleural pressure or respirator pressure when a respirator is used, (6) peak inspiratory flow, (7) peak expiratory flow, (8) mean tidal volume, (9) resistance, (10) compliance, and (11) work: ventilation ratio.
      More work is required to ventilate a patient after all operations, and the work expenditure is proportionately greater than the increase in ventilation. This decreased efficiency is paralleled by a decrease in compliance, the latter representing distensibility of the lungs. This is further illustrated by the observation that tidal volume did not change significantly throughout the postoperative period.
      Respiratory resistance showed no immediate change; however, this parameter may be a good indicator of late airway obstruction.
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