Response

Abstract

On behalf of my coauthors I would like to thank Dr Reade for his comments and questions. He asks if nurses were able to make subjective delirium assessments on patients who had RASS scores of −4 and −5 and were thus rated as “unable to assess” by the CAM-ICU raters. The answer is that it was left to the nurses’ discretion not to rate patients if they were comatose. No patients who had RASS scores of −4 or −5 were subjectively rated by the nurses.Reade points out a sentence in our abstract regarding the use of objective criteria with the CAM-ICU allowing “detection of delirium in more patients,”1(pe12) that we could have more clearly stated as follows: “While the overall delirium incidence found with the CAM-ICU was lower than subjectively rated, objective criteria helped detect delirium in a significant number of patients who were subjectively rated ‘non-delirious.’”He states that we implied, “that the CAM-ICU is the only correct method for identifying delirium.” This was not our intention. In fact, we emphasized that “the CAM-ICU is not a gold standard for diagnosis of delirium.”1(pe18) The truth is that most of the world uses a subjective and variable method by which to pay attention to delirium, and thus subjectivity is part of usual care in many ICUs. Our methodology, chosen a priori and based on previous literature showing that subjectivity misses hypoactive delirium,2 was to consider a formal and validated mechanism as the formal and definitive approach to study discrepancy between the two. At the same time, however, we clearly stated the fact that the CAM-ICU can miss cases of delirium. We would like to take the opportunity to emphasize, that any other validated delirium instrument might have served a similar purpose as a comparator to variable and loose subjective “guestimates.”Reade criticizes the expression CAM-ICU delirium, because CAM-ICU positivity “does not necessarily universally equate to the pathophysiological condition being sought. . . .” The expression CAM-ICU delirium was only chosen to express exactly what Reade pointed out: delirium assessment was done with the CAM-ICU in our study. It is true, however, that out of the nearly dozen DSM-IV validation studies of the CAM-ICU, it has been absolutely consistent that CAM-ICU specificity is exceedingly high. Better said, although sometimes the CAM-ICU may miss some delirium (eg, patients with lower severity of illness, whose inattention is better diagnosed with a 10- to 30-minute instrument), when it is positive it is highly likely to represent delirium in all patient populations studied to date.Reade stated that “concluding a bedside nurse was wrong to administer sedation . . . simply because their CAM-ICU was negative . . . ignores the realities of ICU practice.” The reality in many countries is that drugs must be prescribed by physicians. So, it is the physicians’ responsibility to verify or exclude delirium, pain, or other reasons for disorientation such as an underlying dementia. It is also a reality of ICU practice that physicians mostly rely on the nurses’ subjective clinical impressions, because they are present at the bedside much more often than physicians.We agree with Reade that it would be interesting to determine whether or not patients treated according to subjective impressions have better outcomes as compared to those treated according to objective delirium criteria.