What is the relationship between Fentanyl (a synthetic opioid) and chest wall rigidity?

From the Guidelines

Fentanyl can cause chest wall rigidity, especially when administered rapidly or in high doses, and this condition can be managed with neuromuscular blocking agents and immediate intubation and mechanical ventilation. This condition, also known as "wooden chest syndrome," involves severe muscle stiffness that can impair ventilation and make bag-mask ventilation difficult or impossible. According to 1, rapid administration of fentanyl has been associated with both glottic and chest wall rigidity, even with dosages as low as 1mg/kg. To prevent this complication, fentanyl should be titrated slowly over several minutes when used for treatment of pain, as recommended by 1.

Some key points to consider when administering fentanyl include:

• Administering fentanyl slowly (over 3-5 minutes) to reduce the risk of chest wall rigidity
• Using lower doses when possible (less than 5 mcg/kg) to minimize the risk of complications
• Having neuromuscular blockers immediately available when giving high-dose fentanyl
• Being prepared to rapidly secure the airway if chest wall rigidity occurs, as this complication can quickly lead to hypoxemia and respiratory failure if not promptly addressed
• Monitoring patients closely for signs of respiratory depression, which may last longer than the analgesic effect of fentanyl, as noted by 1

The mechanism of fentanyl-induced chest wall rigidity involves its action on mu-opioid receptors in the central nervous system, particularly in the striatum and basal ganglia, causing increased muscle tone. This effect is dose-dependent and more common in extremes of age (very young and elderly), highlighting the need for careful dose titration and monitoring in these populations. By prioritizing careful administration and monitoring, healthcare providers can minimize the risk of chest wall rigidity and ensure safe and effective use of fentanyl for pain management.

From the FDA Drug Label

Transient neonatal muscular rigidity has been observed in infants whose mothers were treated with intravenous fentanyl The relationship between Fentanyl and chest wall rigidity is that chest wall rigidity (referred to as muscular rigidity in the label) has been observed in infants whose mothers were treated with intravenous fentanyl. Key points:

• Muscular rigidity is noted in the context of neonatal effects.
• The label does not provide information on the incidence or severity of this effect.
• The information provided is based on the use of intravenous fentanyl in mothers during labor 2.

From the Research

Relationship Between Fentanyl and Chest Wall Rigidity

• Fentanyl, a synthetic opioid, has been associated with chest wall rigidity, a complication that can lead to respiratory failure 3, 4, 5, 6, 7.
• This condition is characterized by pronounced abdominal and thoracic rigidity, asynchronous ventilation, and respiratory failure 4.
• Chest wall rigidity can occur with analgesic doses of fentanyl and related compounds, and is not limited to anesthetic doses 3.
• The exact mechanism of fentanyl-induced chest wall rigidity is not fully understood, but it is thought to be related to the drug's effect on skeletal muscle rigidity 7.

Clinical Presentation and Treatment

• Patients with fentanyl-induced chest wall rigidity may present with severe ventilator desynchrony, hypercarbia, and decreased pulmonary compliance 5.
• Treatment options include ventilatory support, reversal with naloxone, and the use of short-acting neuromuscular blocking agents 3, 4, 6.
• Naloxone has been shown to be effective in reversing chest wall rigidity and improving ventilator compliance in patients with fentanyl-induced rigid chest syndrome (FIRCS) 4.
• Gradual reduction in fentanyl infusion can also lead to improvement in ventilation and reduction of episodes of reduced lung compliance 5.

Risk Factors and Patient Outcomes

• Fentanyl-induced chest wall rigidity can occur in patients of all ages, including infants and adults 3, 4, 5, 6, 7.
• The condition is often under-recognized, leading to increased morbidity and mortality 4.
• Prompt recognition and management of fentanyl-induced chest wall rigidity are necessary for improved patient outcomes 4, 6.
• Further research is needed to increase awareness and recognition, identify patient risk factors, and analyze the efficacy and safety of interventions 4.