Prolonged infusion of sedatives and analgesics in adult intensive care patients: A systematic review of pharmacokinetic data reporting and quality of evidence

Differential Effects of Gamma-Aminobutyric Acidergic Sedatives on Risk of Post-Extubation Delirium in the ICU: A Retrospective Cohort Study From a New England Health Care Network

OBJECTIVES

To evaluate whether different gamma-aminobutyric acidergic (GABAergic) sedatives such as propofol and benzodiazepines carry differential risks of post-extubation delirium in the ICU.

DESIGN

Retrospective cohort study.

SETTING

Seven ICUs in an academic hospital network, Beth Israel Deaconess Medical Center (Boston, MA).

PATIENTS

Ten thousand five hundred and one adult patients mechanically ventilated for over 24 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We tested the hypothesis that benzodiazepine versus propofol-based sedation is associated with fewer delirium-free days within 14 days after extubation. Further, we hypothesized that the measured sedation level evoked by GABAergic drugs is a better predictor of delirium than the drug dose administered. The proportion of GABAergic drug-induced deep sedation was defined as the ratio of days with a mean Richmond Agitation-Sedation Scale of less than or equal to -3 during mechanical ventilation. Multivariable regression and effect modification analyses were used. Delirium-free days were lower in patients who received a high proportion of deep sedation using benzodiazepine compared with propofol-based sedation (adjusted absolute difference, -1.17 d; 95% CI, -0.64 to -1.69; p < 0.001). This differential effect was magnified in elderly patients (age > 65) and in patients with liver or kidney failure (p-for-interaction < 0.001) but not observed in patients who received a low proportion of deep sedation (p = 0.95). GABAergic-induced deep sedation days during mechanical ventilation was a better predictor of post-extubation delirium than the GABAergic daily average effective dose (area under the curve 0.76 vs 0.69; p < 0.001).

CONCLUSIONS

Deep sedation during mechanical ventilation with benzodiazepines compared with propofol is associated with increased risk of post-extubation delirium. Our data do not support the view that benzodiazepine-based compared with propofol-based sedation in the ICU is an independent risk factor of delirium, as long as deep sedation can be avoided in these patients.

Clinical phenotypes of delirium during critical illness and severity of subsequent long-term cognitive impairment: a prospective cohort study

BACKGROUND

Delirium during critical illness results from numerous insults, which might be interconnected and yet individually contribute to long-term cognitive impairment. We sought to describe the prevalence and duration of clinical phenotypes of delirium (ie, phenotypes defined by clinical risk factors) and to understand associations between these clinical phenotypes and severity of subsequent long-term cognitive impairment.

METHODS

In this multicentre, prospective cohort study, we included adult (≥18 years) medical or surgical ICU patients with respiratory failure, shock, or both as part of two parallel studies: the Bringing to Light the Risk Factors and Incidence of Neuropsychological Dysfunction in ICU Survivors (BRAIN-ICU) study, and the Delirium and Dementia in Veterans Surviving ICU Care (MIND-ICU) study. We assessed patients at least once a day for delirium using the Confusion Assessment Method-ICU and identified a priori-defined, non-mutually exclusive phenotypes of delirium per the presence of hypoxia, sepsis, sedative exposure, or metabolic (eg, renal or hepatic) dysfunction. We considered delirium in the absence of hypoxia, sepsis, sedation, and metabolic dysfunction to be unclassified. 3 and 12 months after discharge, we assessed cognition with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). We used multiple linear regression to separately analyse associations between the duration of each phenotype of delirium and RBANS global cognition scores at 3-month and 12-month follow-up, adjusting for potential confounders.

FINDINGS

Between March 14, 2007, and May 27, 2010, 1048 participants were enrolled, eight of whom could not be analysed. Of 1040 participants, 708 survived to 3 months of follow-up and 628 to 12 months. Delirium was common, affecting 740 (71%) of 1040 participants at some point during the study and occurring on 4187 (31%) of all 13 434 participant-days. A single delirium phenotype was present on only 1355 (32%) of all 4187 participant-delirium days, whereas two or more phenotypes were present during 2832 (68%) delirium days. Sedative-associated delirium was most common (present during 2634 [63%] delirium days), and a longer duration of sedative-associated delirium predicted a worse RBANS global cognition score 12 months later, after adjusting for covariates (difference in score comparing 3 days vs 0 days: -4·03, 95% CI -7·80 to -0·26). Similarly, longer durations of hypoxic delirium (-3·76, 95% CI -7·16 to -0·37), septic delirium (-3·67, -7·13 to -0·22), and unclassified delirium (-4·70, -7·16 to -2·25) also predicted worse cognitive function at 12 months, whereas duration of metabolic delirium did not (1·14, -0·12 to 3·01).

INTERPRETATION

Our findings suggest that clinicians should consider sedative-associated, hypoxic, and septic delirium, which often co-occur, as distinct indicators of acute brain injury and seek to identify all potential risk factors that may impact on long-term cognitive impairment, especially those that are iatrogenic and potentially modifiable such as sedation.

FUNDING

National Institutes of Health and the Department of Veterans Affairs.