Do bronchospasms cause resistance with Bag Valve Mask (BVM) ventilation?

Bronchospasms and Bag Valve Mask Ventilation Resistance

Yes, bronchospasms significantly increase resistance during Bag Valve Mask (BVM) ventilation, making effective ventilation more challenging and potentially requiring higher inspiratory pressures to achieve adequate chest rise. 1

How Bronchospasms Affect BVM Ventilation

• Bronchospasms cause severe bronchial constriction, which increases airway resistance and decreases lung compliance, making it more difficult to deliver effective ventilation with a BVM 1
• During bronchospasm, patients may exhibit wheezing, prolonged expiration, and increased work of breathing, all signs of increased airway resistance 1
• The narrowed airways require higher inspiratory pressures to achieve adequate tidal volumes and visible chest rise 1
• Standard pressure-relief valves on some BVM devices may prevent delivery of sufficient tidal volume in patients with bronchospasm-induced high airway resistance 1

Clinical Implications

• Two-person BVM technique is strongly recommended when ventilating patients with bronchospasms to overcome the increased resistance 1
• One rescuer should use both hands to maintain a tight mask-to-face seal while the second rescuer compresses the ventilation bag 1
• Patients with bronchospasms may require bypassing the pressure-relief valve on the BVM to achieve visible chest expansion 1
• Poor lung compliance and increased airway resistance from bronchospasms can make effective ventilation using alternative airway devices like laryngeal mask airways questionable 1

Potential Complications

• Excessive ventilation pressure when trying to overcome bronchospasm-induced resistance can lead to:
  • Increased intrathoracic pressure impeding venous return 1
  • Decreased cardiac output, cerebral blood flow, and coronary perfusion 1
  • Air trapping and barotrauma in patients with small-airway obstruction 1
  • Gastric inflation and increased risk of regurgitation/aspiration 1

Best Practices for BVM Ventilation with Bronchospasms

• Use only the force and tidal volume necessary to just make the chest rise visibly 1
• Give each breath slowly, over approximately 1 second, and watch for chest rise 1
• If the chest does not rise, reopen the airway, verify the mask-to-face seal, and reattempt ventilation 1
• Make sure the BVM device allows bypassing the pressure-relief valve if necessary 1
• Regularly aspirate airways to remove excessive secretions that may accompany bronchospasms 1
• Consider having a larger size BVM available, as adult self-inflating bags (1000 mL) may be needed to reliably achieve chest rise in patients with high resistance 1

Monitoring and Adjustments

• Closely observe for signs of effective ventilation such as bilateral chest movement 2
• Listen for equal breath sounds over both lung fields, especially over the axillae 2
• If bronchospasms are severe and BVM ventilation is ineffective, consider early transition to advanced airway management by experienced personnel 1
• Remember that bronchospasms may cause a decrease in oxygen saturation despite appropriate BVM technique 1

By understanding how bronchospasms increase resistance during BVM ventilation, healthcare providers can adjust their technique accordingly to ensure effective ventilation while minimizing potential complications.