Calculating pulse pressure variation

Pulse pressure is the difference between systolic and diastolic blood pressure. The phases of respiration, denoted by positive (inspiration) and negative (expiration) deflections, reflect those for patients on mechanical ventilation (these would be different if the patient was spontaneously breathing and can vary depending upon the mode of ventilation). PPV can be calculated as follows: PPV = 100 × (PPmax – PPmin) / ([PPmax + PPmin] / 2).