ABCDEF (A2F) Bundle

ABCDEF (A2F) Bundle – Kaele Leonard


  • Post-Intensive Care Syndrome (PICS): complex constellation of cognitive, physical, and psychological impairments that impact most survivors of critical illness, leading to disability, frailty, and poor quality of life
    • Predicted by (1) duration of immobility and (2) delirium; very common in ICU pts
    • Both are reduced by >80% compliance with ABCDEF (A2F) Bundle concepts
  • ABCDEF (A2F) Bundle: Interprofessional, evidence-based safety bundle of care principles to help reduce LOS, mortality, bounce-backs, and the duration of ICU delirium and coma
    • Assess/Prevent/Manage Pain
    • Both SAT/SBT
    • Choice of Analgesia and Sedation
    • Delirium—Assess, Prevent, and Manage
    • Early Mobility and Exercise
    • Family Engagement and Empowerment
  • Goal: allow pt to “prove us wrong” about readiness for liberation from devices, sedatives, etc.
  • Evidence Associated with higher likelihood of ICU and hospital discharge and lower likelihood of death, mechanical ventilation, coma, delirium, physical restraint, ICU readmission, discharge to a destination other than home, and lower cost


Assess, prevent, and manage pain

  • Tools to assess pain using facial expressions, body movements, muscle tension, compliance with ventilator, or vocalization for extubated pts
    • Behavioral Pain Scale (BPS): scale 0-12, uncontrolled pain ≥ 5
    • Critical Care Pain Observation Tool (CPOT): scale 0-8, uncontrolled pain 3 if non-verbal pt
  • Uncontrolled pain increases risk for delirium, limits inspiratory effort and weaning from ventilator, and limits ability to mobilize
  • Treatment: multi-modal with parenteral opioids (e.g., fentanyl, dilaudid), neuropathic meds (e.g., gabapentin, ketamine), adjunctive non-opioids analgesics (e.g., acetaminophen, NSAIDs), nonpharmacologic interventions (repositioning, heat/cold)


Both spontaneous awakening trials (SATs) and spontaneous breathing trials (SBTs)

  • SATs = daily sedative interruptions
    • RN-driven protocol involving safety checklist: no active seizures, alcohol withdrawal, agitation, paralytics, myocardial infarction, or increased ICP
    • If pass SAT, then proceed to SBT
    • If fail SAT (anxiety, agitation, pain, resp distress) restart sedation at ½ doses
  • SBTs = PS ventilation (Fi02 ≤ 50%, PEEP ≤ 7.5; typically 40% and 5/5) for ≥ 30 minutes
    • RT or physician/APP-driven protocol with safety screen: passed SAT, O2 sat ≥ 88%, inspiratory efforts, no myocardial ischemia, no/low vasopressor support
    • If pass SBT, physician/APP judgment on extubation
    • If fail SBT (RR > 35 or < 8, O2 sat < 88%, resp distress, mental status change) restart full ventilatory support
  • Evidence:
    • Liberated pts from mechanical ventilation 3 days sooner, decreased ICU and hospital length of stay by 4 days, and 14% absolute reduction in mortality at 1 year


Choice of analgesia and sedation

  • Richmond Agitation-Sedation Scale (RASS): sedation and level of arousal assessment tool (Figure 1)
    • Target light sedation of RASS -1 to 0 with goal of (1) pt following commands without agitation and (2) limiting immobilization
    • Over-sedation:  hold sedatives till target, then restart at ½ prior dose
  • Analgosedation with focus on treating pain first and then adding sedation meds PRN
  • Sedatives: dexmedetomidine (dex) or propofol >>> benzodiazepines
    • Benzodiazepines increase risk of delirium in a dose-dependent fashion



Figure 1: Richmond Agitation-Sedation Scale (RASS)


Delirium - assess, prevent, and manage

  • Screening for delirium: q4hr using CAM-ICU (Figure 2)
    • Affects 60-80% of ventilated pts and associated with increased morbidity and mortality, longer ICU and hospital length of stay, long-term cognitive dysfunction
  • Risk factors and treatment: see Delirium topic under Geriatrics
    • Dr. Dre mnemonic:  Disease remediation (heart failure, COPD, and sepsis), Drug removal (benzos, anticholinergics, steroids) and Environment (hearing aids, eye glasses, mobilize the pt, normalize sleep wake cycle)


Early mobility and Exercise

  • Prolonged immobilization during critical illness leads to ICU-acquired weakness, associated with worse outcomes: mechanical ventilation, increased hospital length of stay, greater mortality, and greater disability
  • Consult PT/OT to initiate rehab at the beginning of critical illness
    • Can be done safely in pts receiving advanced support
    • duration of delirium, ICU and hospital length of stay, and improved return to independent functional status


Family engagement and empowerment

  • Especially important when pts are unable to communicate themselves
  • Incorporate family at the bedside and on rounds to learn pt preferences and values, engage in shared-decision making, and address questions and concerns
    • Associated with greater satisfaction with care and increased feelings of inclusion, respect, and understanding of the pt’s care
    • Can facilitate family decision to transition to comfort-focused care



Figure 2: Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)