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Predictors of PTSD in Ventilated ICU Patients
Abstract & Commentary
By David J. Pierson, MD, Editor, Professor, Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, is Editor for Critical Care Alert.
Synopsis: Among survivors of critical illness requiring mechanical ventilation who were followed up at 6 months, symptoms of PTSD were more common in women, in those under age 50, and in those who had received higher doses of lorazepam during their ICU stay.
Source: Girard TD et al. Crit Care. 2007 Feb 22;11(1):R28 [Epub ahead of print].
This pilot study from the Medical and Coronary ICUs at Vanderbilt University Medical Center sought to identify factors associated with the development of symptoms of post-traumatic stress disorder (PTSD) following critical illness. The authors prospectively evaluated all English-speaking patients without underlying neurological impairment who required mechanical ventilation during the study period. In those enrolled, they recorded demographics, ICU admission diagnoses, APACHE II score, and Charlson Comorbidity Index, and evaluated them daily for delirium using the CAM-ICU scale previously developed by the authors. They also recorded all doses of sedatives and narcotic analgesics administered to the patients. They then followed the patients up at 6 months using a validated 2-part questionnaire (the PTSS-10) for assessing symptoms of PTSD.
A total of 280 of the 555 patients potentially eligible for inclusion in the study were excluded according to a priori criteria, leaving 275 enrolled patients, 96 of whom died during hospitalization and 179 were potentially eligible for follow-up. Of the 179, 86 were lost to follow-up, 23 died within 6 months, and 27 were judged too ill at 6 months to participate or declined to participate. Thus, 43 patients (24% of those eligible at discharge) were included in the follow-up study. Of these, 6 (14%) scored more than 35 points on the PTSS-10, consistent with a diagnosis of PTSD. These 6 patients were compared to the others who were evaluated at 6 months to look for associations and potential predictors of the disorder.
Female patients had more PTSD than males on multivariable analysis. High levels of PTSD symptoms were less likely to occur in older patients, with these symptoms significantly less likely in those older than age 50. Although overall the amount of sedatives (benzodiazepines and/or propofol) and opioids administered to the patients did not correlate with development of PTSD, the total dose of lorazepam was positively associated with PTSD by both univariate and multivariable analysis. The duration of delirium did not differ among patients who did and did not develop PTSD.
This small but carefully done prospective study found PTSD in 14% of patients who survived a critical medical illness requiring mechanical ventilation. PTSD symptoms were more likely to occur in women, in patients older than age 50, and in patients who received higher cumulative doses of lorazepam.
Only 6 patients met diagnostic criteria for PTSD in this study. Thus, it should be regarded as a pilot study, as the authors emphasize, and its results should be interpreted cautiously. For example, one must not read too much into the association between lorazepam dose and PTSD, given the small numbers involved and the fact that no association was evident for midazolam, the other benzodiazepine commonly used. However, it is becoming increasingly clear from this and other studies that PTSD occurs in a significant minority of patients who survive a critical illness. As the authors point out, patients and their families should be made aware of this complication, and clinicians following patients after hospital discharge should be prepared to recognize and deal with PTSD if it occurs.