This Clinical Pulmonary Infection Score (CPIS) for VAP calculator assists in the diagnosis of ventilator associated pneumonia and offers risk stratification. Below the form you can find more on how the score is calculated and how it reflects on the probability of pulmonary infections.
How does the Clinical Pulmonary Infection Score (CPIS) calculator work?
This is a health tool used to evaluate the existence of a clinical pulmonary infection, often in conjunction with other diagnostic means for ventilator-associated pneumonia (VAP).
The original study concerned the comparison between the clinical characteristics of diagnostic testing with blind endotracheal sampling with bronchoscopically obtained samples in the diagnosis of VAP.
As a clinical measure, this Clinical pulmonary infection score - CPIS calculator helps the clinician decide whether the patient in question would benefit from a pulmonary culture testing.
By using the CPIS, unnecessary antibiotic administration due to treatment of colonized patients is prevented and the incidence of misdiagnosed VAPs is lowered.
The six variables investigated are described below:
■ Temperature in Celsius degrees – checks whether the patient is febrile or not.
■ Blood leukocytes /mm3 – evaluates the number and whether there are more than 50% band formations.
■ Tracheal secretions – assesses the presence of non purulent or purulent secretions or the entire absence.
■ Oxygenation, PaO2/FiO2 in mmHg – oriented around the 240 cut off point with or without ARDS (Acute respiratory distress syndrome) which is defined as PaO2/FiO2 <200, PCWP <18, and acute bilateral infiltrates.
■ Pulmonary radiography – evaluates the presence or absence of infiltrates and in the former case, their aspect, whether diffuse or localized.
■ Culture of tracheal aspirate – assesses whether the pathogenic bacteria is in rare/ light quantity, moderate or heavy quantify and if it is seen on gram stain.
The fever and extent of oxygenation impairment are reflective of pneumonia symptoms and the overall score correlates with VAP presence, although quantitative microbiological criteria should still be put in place.
At the same time oxygenation measure and the blood leukocyte count are the only variables to weight on the mortality diagnosis from the six presented.
Subsequent validation studies could not strengthen the low and limited specificity and sensitivity of CPIS (compared to the quantitative cultures of bronchoalveolar lavage fluid) and the tool could not be validated for other pulmonary conditions such as COPD or acute lung injury.
Another criticism of the model is that inter observer variability is substantial, thus making it imposible to use in randomized clinical trials.
CPIS score interpretation
Each of the six parameters used in the CPIS is awarded a different number of points depending on the answer choice selected. The answers are placed on an ordinal scale from 0 to 2 points, where 0 indicates low aspect closer to normal and 2 suggests a more severe aspect of the parameter.
The overall result ranges from 0 to 12, 0 being normal and 12 being high risk for VAP.
In the original study there is a cutoff for high risk situated at 6 points. Scores below 6 indicate a low risk of pulmonary infection while scores of 6 and above indicate a high risk.
VAP medical guidelines
Ventilator-associated pneumonia is responsible for more than a quarter of ICU acquired infections and accounts for more than one half of antibiotic use in the same department, not to mention the morbidity rates.
While hospitals are determined to lower these rates, it is still obvious that specific diagnostic and prevention tools are required as up to date there is no gold standard for this condition.
The Harborview Medical Center has devised a therapeutic algorithm, extracts of which are presented in the following paragraphs.
The clinical suspicion of VAP should be based on:
■ x-ray criteria;
■ One or more of the following: fever, purulent endotracheal secretions, leukocytosis;
■ No introduction of new antimicrobials for more than 72 hours.
If the patient is hemodynamically stable the indication is for bronchoscopy but if not, the clinician can choose whether to perform it or not. At this stage CPIS result can be taken in consideration.
Different antibiotic therapies are recommended, depending on whether the patient has been hospitalized for more or less than 4 days and whether the diagnosis is of early or late VAP.
Antimicrobial treatment can be discontinued if bronchoalveolar lavage is less than 104 CFU/mL or brush specimen less than 103 CFU/mL. In case the values are yet above the specified limits, the antimicrobial should be de-escalated.
1) Rea-Neto A, Cherif N, Youssef M et al. (2008) Diagnosis of ventilator-associated pneumonia: a systematic review of the literature. Crit Care; 12(2): R56.
2) Zilberberg MD, Shorr AF. Ventilator-Associated Pneumonia: The Clinical Pulmonary Infection Score as a Surrogate for Diagnostics and Outcome. Oxford Journals Medicine & Health Clinical Infectious Diseases V51, IS 1Pp. S131-S135.
3) Schurink CA, Van Nieuwenhoven CA, Jacobs JA, Rozenberg-Arska M, Joore HC, Buskens E, Hoepelman AI, Bonten MJ. (2004) Clinical pulmonary infection score for ventilator-associated pneumonia: accuracy and inter-observer variability. Intensive Care Med; 30(2):217-24.
4) Croce MA, Swanson JM, Magnotti LJ, Claridge JA, Weinberg JA, Wood GC, Boucher BA, Fabian TC. (2006) The futility of the clinical pulmonary infection score in trauma patients. J Trauma; 60(3):523-7; discussion 527-8.28 Jan, 2016