Wooden chest rigidity is seen with

Fentanyl induced chest wall rigidity seen with high bolus dose of fentanyl. CWR related to opiate administration was first described by Hamilton and Cullen in 1953 . Following opiate administration, clinicians may observe significant difficulty with mask ventilation, respiratory arrest, and a rigid chest wall; this phenomenon has been noted with various opioid substances. The majority of repoed cases and physiologic studies focus on CWR occurring with high opioid doses --administeredas pa of anesthetic induction