An induced coma (also called therapeutic sedation or, in the post-cardiac arrest context, targeted temperature management with sedation) is a medically controlled state of unconsciousness. Sedative and anaesthetic medications are given intravenously to keep the patient deeply asleep, allowing the body to recover from the effects of cardiac arrest and enabling the critical care team to manage breathing via a mechanical ventilator and monitor organ function closely.
After cardiac arrest, sedation is typically used for one of two purposes. First, it is required as part of targeted temperature management (TTM), where the patient’s body temperature is lowered to 32 to 36°C for 24 hours to protect the brain from secondary injury after oxygen deprivation. A sedated, ventilated patient is also more stable for critical care monitoring and management in the hours immediately after resuscitation. Second, sedation allows the brain time to recover without the additional demands of consciousness, movement, and agitation.
Sedation is carefully titrated to achieve the required depth while avoiding excessive doses that could delay recovery or cause complications. The critical care team uses clinical assessment and sometimes brain monitoring to guide this. A sedation hold is performed once TTM is complete, gradually lightening sedation to allow the patient to wake and to enable neurological assessment.
For families, an induced coma can be a frightening and confusing experience. Their loved one appears unresponsive and deeply asleep, attached to multiple monitoring lines and a ventilator. The critical care team should explain what is happening and why, give regular updates, and involve families in the care plan. In most cases, the sedation phase lasts 24 to 48 hours, after which the team begins the process of waking the patient. See also: Targeted Temperature Management, Post-Intensive Care Syndrome.
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