Caring for Critically Ill Patients with the ABCDEF Bundle: Results of the ICU Liberation Collaborative in Over 15,000 Adults

Abstract

Objective: Decades-old, common ICU practices including deep sedation, immobilization, and limited family access are being challenged. We endeavoured to evaluate the relationship between ABCDEF bundle performance and patient-centered outcomes in critical care.

Design: Prospective, multicenter, cohort study from a national quality improvement collaborative.

Setting: 68 academic, community, and federal ICUs collected data during a 20-month period.

Patients: 15,226 adults with at least one ICU day.

Interventions: We defined ABCDEF bundle performance (our main exposure) in two ways: 1) complete performance (patient received every eligible bundle element on any given day) and 2) proportional performance (percentage of eligible bundle elements performed on any given day). We explored the association between complete and proportional ABCDEF bundle performance and three sets of outcomes: patient-related (mortality, ICU and hospital discharge), symptom-related (mechanical ventilation, coma, delirium, pain, restraint use), and system-related (ICU readmission, discharge destination). All models were adjusted for a minimum of 18 a priori determined potential confounders.

Measurements and results: Complete ABCDEF bundle performance was associated with lower likelihood of seven outcomes: hospital death within 7 days (adjusted hazard ratio, 0.32; CI, 0.17-0.62), next-day mechanical ventilation (adjusted odds ratio [AOR], 0.28; CI, 0.22-0.36), coma (AOR, 0.35; CI, 0.22-0.56), delirium (AOR, 0.60; CI, 0.49-0.72), physical restraint use (AOR, 0.37; CI, 0.30-0.46), ICU readmission (AOR, 0.54; CI, 0.37-0.79), and discharge to a facility other than home (AOR, 0.64; CI, 0.51-0.80). There was a consistent dose-response relationship between higher proportional bundle performance and improvements in each of the above-mentioned clinical outcomes (all p < 0.002). Significant pain was more frequently reported as bundle performance proportionally increased (p = 0.0001).

Conclusions: ABCDEF bundle performance showed significant and clinically meaningful improvements in outcomes including survival, mechanical ventilation use, coma, delirium, restraint-free care, ICU readmissions, and post-ICU discharge disposition.

Figure 1.

Association between proportional performance of the ABCDEF bundle and patient-related outcomes. Each panel shows the adjusted hazard ratio and 95% CI for the specified outcome, comparing patients with a given proportion of eligible ABCDEF bundle elements performed on a given day with patients with none of the bundle elements performed that day. The gray line at 1.0 indicates no association. Hazard ratios are adjusted for baseline, ICU admission characteristics, and daily covariates, measured the same day as bundle performance. For example, assuming all other covariates are equal, a patient who had 60% of the ABCDEF bundle elements for which he/she was eligible has on average about 1.4 times the likelihood of being discharged from the ICU on a given day as a patient with none of the bundle elements performed. All three outcomes were significant (p < 0.0001). The covariates adjusted for include demographic variables (age, sex, race, ethnicity, body mass index, residence before admission, mobility restriction before admission), admission features (diagnosis, hospital type [community vs. teaching], and ICU type), and daily ICU characteristics on the day of bundle exposure (receipt of medications, including benzodiazepines, opioids, propofol, dexmedetomidine, typical/atypical antipsychotics; comfort care order; mechanical ventilation; coma). We also adjusted for delirium on the day of bundle exposure when looking at the association between the bundle and delirium. Patients were “eligible to receive” elements A, C, D, and E on all ICU days. Patients were eligible for element B if sedated (part 1, SAT) and/or mechanically ventilated (part 2, SBT), and were eligible for element F if family or another caregiver was present. Therefore, patients were eligible for a maximum of seven and a minimum of four elements on any given day; proportion of elements performed is the number of elements performed, divided by the elements the patient was eligible to receive.

Figure 2.

Association between proportional performance of the ABCDEF bundle and symptom-related outcomes. These data represent the relationship between the proportion of eligible ABCDEF bundle elements performed on a given day and the probability of a daily clinical outcome the following day. For example, the upper left-hand panel represents the relationship between proportion of eligible elements performed on a given day and the probability that the patient would be mechanically ventilated the following day. Lines and confidence bands represent the probability of the outcomes and the 95% CI, adjusted for potential confounders measured at baseline, ICU admission, and daily [Au: daily what?] while in the ICU. Relationships between proportion of elements performed and each outcome were significant (all p < 0.0001). Patients were “eligible to receive” elements A, C, D, and E on all ICU days. Patients were eligible for element B if sedated (part 1, SAT) and/or mechanically ventilated (part 2, SBT), and were eligible for element F if family or another caregiver was present. Therefore, patients were eligible for a maximum of seven and a minimum of four elements on any given day; proportion of elements performed is the number of elements actually performed divided by the elements the patient was eligible to receive.

Figure 3.

Association between proportional performance of the ABCDEF bundle and system-related outcomes. These data show the adjusted probabilities of ICU readmission (p = 0.002) and discharge to a facility versus home (p < 0.0001), respectively, among ICU survivors, according to what proportion of eligible ABCDEF bundle elements were performed during the first 7 days of a patient’s ICU stay. Probabilities are adjusted for baseline, ICU admission, and summary ICU characteristics (e.g., total proportion of ICU days the patient received benzodiazepines). Patients were “eligible to receive” elements A, C, D, and E on all ICU days. Patients were eligible for element B if sedated (part 1, SAT) and/or mechanically ventilated (part 2, SBT), and were eligible for element F if family or another caregiver was present. Therefore, patients were eligible for a maximum of seven and a minimum of four elements on any given day; proportion of elements performed is the number of elements actually performed during the entire ICU stay (up to 7 days) divided by the elements the patient was eligible to receive during that time.