Wednesday February 27, 2008
Ventilation during CPR - dangers of 'over-bagging'


Per new ACLS guidelines, the rescuer should deliver a tidal volume sufficient to produce chest rise (approximately 6 to 7 mL/kg or 500 to 600 mL) over 1 second with 8 to 10 breaths per minute.

The standard ventilation bag used in adult ICUs have capacity of 1600 ml ! and over enthuisatic bagging can lead to further deterioration of cardio-pulmonary status, particulary when ETT is already in place, where all tidal volume gets directly delivered to lungs. It may cause further decrease in cardiac output.

In case of face-mask ventilation, unrealized effect is over gastric inflation leading to regurgitation and aspiration. Moreover, gastric inflation elevate the diaphragm, restrict lung movement and decrease respiratory system compliance.

Sometime its preferable to do one hand bag ventilation rather than two hand ventilation to avoid 'over bagging'. Depending on hand size, grip strength, height and weight tidal volumes delivered by two hands significantly greater than those delivered by one hand.



Reference: click to abstract / article

1. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, Part 7.1: Adjuncts for Airway Control and Ventilation - Circulation. 2005;112:IV-51 – IV-57

2. Comparison of tidal volumes obtained by one-handed and two-handed ventilation techniques, American Journal of Critical Care, Vol 2, Issue 6, 467-473