Cam Icu Calculator

Delirium is defined by a disturbance of attention and awareness that develops acutely and fluctuates, and the CAM-ICU is built to detect exactly that pattern in patients who cannot speak because they are intubated. The algorithm mirrors the diagnostic definition rather than summing symptoms: Feature 1 captures acute change or fluctuation from baseline, Feature 2 captures inattention, and delirium requires both, plus either Feature 3 (level of consciousness altered, meaning any RASS other than 0) or Feature 4 (disorganized thinking). Inattention is measured objectively with the ten-letter Attention Screening Examination, in which the patient squeezes on each A in the sequence SAVEAHAART; more than 2 errors is positive. Feature 4 uses four yes-or-no questions plus a two-part finger command, with more than 1 error scored positive. A RASS of -4 or -5 makes the assessment invalid, because an unarousable patient cannot demonstrate attention; the correct action is to defer, not to record a negative. Reported sensitivity in validation studies is roughly 93 to 100 percent with specificity of 89 to 100 percent, though real-world performance in units without ongoing training is considerably lower, which is the main practical limitation. Prevalence in mechanically ventilated cohorts commonly runs 60 to 80 percent. The tool detects delirium but does not grade its severity, and it does not distinguish delirium from an unrecognized structural or metabolic brain injury, so a newly positive result still warrants a clinical explanation.

The parent instrument, the Confusion Assessment Method, was developed by Sharon Inouye and colleagues and published in Annals of Internal Medicine in 1990. It condensed psychiatric diagnostic criteria for delirium into four operational features that a non-psychiatrist could apply at the bedside, and it became the most widely used delirium instrument in general medicine and geriatrics. It could not be used in intensive care, however, because its features depend on verbal responses that an intubated patient cannot give. E. Wesley Ely and colleagues at Vanderbilt University adapted it for that population, replacing spoken answers with squeeze-to-signal and picture-recognition tasks, and published the CAM-ICU validation in 2001 in both JAMA and Critical Care Medicine. In the same year, Bergeron and colleagues published the Intensive Care Delirium Screening Checklist as an alternative approach. The CAM-ICU was pushed into routine practice by the recognition through the 2000s that delirium duration independently predicts mortality and long-term cognitive impairment among survivors. The Society of Critical Care Medicine named it, alongside the ICDSC, as a recommended screening tool in the 2013 pain, agitation and delirium guidelines and again in the 2018 PADIS update, where delirium monitoring became the D element of the ABCDEF bundle. Its pairing with the RASS, which supplies both the gate for assessability and Feature 3, dates from the original ICU adaptation.