Undersedation

Undersedation is a clinical condition in which a patient receives an insufficient depth of sedation or analgesia during anesthesia, procedural sedation, or critical care. It results in inadequate comfort, awareness or responsiveness and may necessitate additional dosing or escalation of care. It is distinguished from oversedation, which involves excessive sedation and potential respiratory compromise.

In surgical anesthesia, procedural sedation (for example, endoscopy or dental procedures), and intensive care settings with mechanical ventilation or invasive monitoring, the goal is to provide analgesia and anxiolysis while maintaining patient safety and airway control. The required depth of sedation varies by procedure, patient factors, and clinical goals.

Patients may remain anxious or in pain, move or resist, vocalize distress, and exhibit tachycardia, hypertension, crying or agitation. Inadequate sedation can lead to increased movement, procedure delays, poor imaging, self-harm risk, or failure to cooperate with airway management. It can also provoke stress responses that destabilize vital signs.

Causes include under-dosing due to miscalculation, rapid drug clearance, drug interactions, or use of short-acting agents; high pain or anxiety levels; high body mass or unusual physiology; equipment or monitoring failures; and inadequate assessment or failure to titrate to effect.

Management and prevention involve pre-procedure assessment of pain, anxiety, and airway risk; use of titratable sedation with validated scales such as the Richmond Agitation-Sedation Scale (RASS) or Ramsay scale to guide dosing; multimodal analgesia; careful monitoring of oxygenation, ventilation, and hemodynamics; readiness to provide airway support and reversal agents; and ensuring adequate monitoring and staffing to permit timely adjustment, with documentation of the depth of sedation and response to dosing.