Flow volume loop with increased resistance

Flow volume loops may be displayed on an anesthesia machine with inspiration above the horizontal axis, and volume increasing from left to right. When displayed this way, breaths progress in a clockwise direction, as shown by the arrows in this figure. The normal curve is shown by the solid line. The dashed line shows the curve with increased lung resistance. Normalization of the flow volume loop can be used to monitor treatment. For further information, refer to UpToDate content on monitoring pulmonary mechanics during mechanical ventilation in anesthesia.