How to Calculate a CPIS Score

The Clinical Pulmonary Infection Score is an algorithm used to determine the pre-test probability of a ventilated patient being infected with a ventilator-associated pneumonia to decide whether there is any benefit to obtaining a respiratory cultures in order to make the diagnosis. The CPIS takes into account the patient's temperature, white blood cell count, if there are any tracheal secretions, the ratio of the patient's arterial oxygen partial pressure to the fraction of oxygen in the inspired air, and the results of a chest x-ray. A score greater than six indicates that a respiratory culture obtained via bronchoalveolar lavage or mini-BAL may be beneficial.

Instructions

• 1

  Check the patient's temperature and record CPIS points. For a temperature greater than or equal to 39.0C or less than or equal to 36.5C, record two points. If the temperature is greater than or equal to 38.5C or less than or equal to 38.9C, record one point. If the patient's temperature is greater than or equal to 36.5C or less than or equal to 38.4C, record zero points.

• 2

  Look at the patient's WBC count to determine the next component of the CPIS. If the WBC count is less than 4,000 or greater than 11,000 with 50 percent bands, record two points. If the WBC count is less than 4,000 or greater than 11,000, record one point. If the WBC count is greater than or equal to 4,000 or less than or equal to 11,000 record zero points.

• 3

  Examine the patient for tracheal secretions. If there are purulent secretions, meaning secretions that are green or yellow and suggestive of infection, record two points. However, if the secretions are non-purulent, record one point. If there are no secretions, record zero points.

• 4

  Calculate the ratio of the arterial partial pressure of oxygen, as determined from an arterial blood gas, to the fraction of inspired oxygen, which is based on the ventilator settings. For a ratio greater than 240, record zero points and for a ratio less than or equal to 240 record two points.

• 5

  Examine the chest x-ray to determine the next component of the CPIS. A chest x-ray showing a patchy infiltrate adds two points, while one showing diffuse infiltrates adds one point, and an x-ray showing no infiltrates earns no points.

• 6

  Total the points. A score greater than six indicates that respiratory cultures obtained via bronchoalveolar lavage will be helpful in diagnosing VAP.