Part 7.1: Adjuncts for Airway Control and Ventilation This section highlights recommendations for the support maximize arterial oxygen saturation and, in turn, arterial of ventilation and oxygenation during resuscitation and oxygen content. This will help support oxygen delivery the periarrest period. The purpose of ventilation during CPR (cardiac output x arterial oxygen content) when cardiac to output is limited. This short-term oxygen therapy does not tion of carbon dioxide. but research has not identified the produce oxygen toxicity optimal tidal volume, respiratory rate, and inspired oxygen oncentration required to do so. During the first minutes of ventricular fibrillation sudden cardiac arrest (VF SCA), rescue breaths are probably not as important as chest com- Bag-Mask Ventilation All healthcare providers should be familiar with the use of the pressions,because oxygen delivery to the tissues, including bag-mask device for support of oxygenation and ventila- the heart and brain, appears to be limited more by blood flow than by arterial oxygen content. Thus, during the first minutes the first few minutes of resuscitation or when placement of an of VF SCA the lone rescuer should attempt to limit interrup advanced airway is delayed or unsuccessful. Effective bag- provider must be careful to limit interruptions in chest mask ventilation requires adequate training and frequent check the rhythm The desirable components of a bag-mask device are Ventilation and compressions are both thought to be in Part 4: Adult Basic Life Support. "When using important for victims of prolonged VF SCA and for all mask device (ie, no advanced airway is in place), the victims of asphyxial arrest(eg, drowning victims and victims should deliver a tidal volume sufficient to produce chest rise of drug overdose with primary respiratory arrest) because (approximately 6 to 7 mL/kg or 500 to 600 mL) over I these victims are hypoxemic be efore arrest second.5 This volume of ventilation minimizes the risk of Because systemic and, therefore, lung perfusion is substan- gastric inflation. The rescuer should be sure to open the tially reduced during CPR, rescuers can support a normal airway adequately with a chin lift, lifting the jaw against the ventilation-perfusion match with a minute ventilation that is mask and holding the mask against the face, creating a tigl much lower than normal. During CPR with an advanced seal During CPR, give 2 breaths during a brief (about 3 to 4 seconds)pause after every 30 chest compressions. When an breathing(see Part 4: "Adult Basic Life Support")than that advanced airway(eg, endotracheal tube, esophageal-tracheal recommended in the ECC guidelines 2000. During the combitube [Combitube], or laryngeal mask airway LMA) prearrest and postarrest periods, the patient will require replaces the face mask, rescuers should deliver 8 to 10 breaths upport of oxygenation and ventilation with tidal volumes and respiratory rates that more closely approximate normal. per minute during CPR. Deliver each breath over about I Beyond the first minutes of cardiac arrest, tissue hyp second while chest compressions are delivered at a rate of 100 velops. CPR provides approximately 25% to 33% of per minute, and do not attempt to synchronize the compres ions with the ventilations ac outpu This low-flow state maintains a small but critical amount of blood flow to the heart and brain, but For ventilation of patients with a perfusing rhythm (ie, tissue hypoxia will persist until restoration of effective better pulmonary blood flow than is present during CPR) spontaneous perfusion. Additional factors that contribute to deliver approximately 10 to 12 breaths per minute(1 breath hypoxia include intrapulmonary shunting with microcircular- every 6 to 7 seconds). Deliver these breaths over I second tory dysfunction and attendant ventilation-perfusion abnor- when using a mask or an advanced airway malities. Some patients may also have underlying respiratory In patients with severe obstructive pulmonary disease and disease. Tissue hypoxia leads to anaerobic metabolism and increased resistance to exhalation, providers should try to metabolic acidosis. Acid-base imbalance occasionally blunts prevent air trapping that may result in inadvertent generation the beneficial effects of chemical and electrical therapy of intrinsic positive end-expiratory pressure(PEEP),So To improve oxygenation, healthcare providers should give called"auto-PEEP. "In patients with hypovolemia,auto- 100% inspired oxygen(Fio=1. 0)during basic life support PEEP may substantially reduce cardiac output and blood and advanced cardiovascular life support as soon as it pressure. To prevent this, use lower respiratory rates(eg, 6 to becomes available. High inspired oxygen tension will tend to 8 breaths per minute)in these patients, allowing more time for comple 2005;112:IV51IV57.) Bag-mask ventilation can produce gastric inflation with e 2005 American Heart Association complications, including regurgitation, aspiration, and pneu This special supplement to Circulation is freely available at http://www.circulationaha.org monia Gastric inflation can elevate the diaphragm, restrict lung movement, and decrease respiratory syster DOI: 10.1161/CIRCULATIONAHA 105 166556 IV-5IPart 7.1: Adjuncts for Airway Control and Ventilation This section highlights recommendations for the support of ventilation and oxygenation during resuscitation and the periarrest period. The purpose of ventilation during CPR is to maintain adequate oxygenation and sufficient elimina￾tion of carbon dioxide, but research has not identified the optimal tidal volume, respiratory rate, and inspired oxygen concentration required to do so. During the first minutes of ventricular fibrillation sudden cardiac arrest (VF SCA), rescue breaths are probably not as important as chest com￾pressions, because oxygen delivery to the tissues, including the heart and brain, appears to be limited more by blood flow than by arterial oxygen content. Thus, during the first minutes of VF SCA the lone rescuer should attempt to limit interrup￾tions in chest compressions for ventilation. The advanced provider must be careful to limit interruptions in chest compressions for attempts to insert an advanced airway or check the rhythm. Ventilation and compressions are both thought to be important for victims of prolonged VF SCA and for all victims of asphyxial arrest (eg, drowning victims and victims of drug overdose with primary respiratory arrest) because these victims are hypoxemic before arrest. Because systemic and, therefore, lung perfusion is substan￾tially reduced during CPR, rescuers can support a normal ventilation-perfusion match with a minute ventilation that is much lower than normal. During CPR with an advanced airway in place we now recommend a lower rate of rescue breathing (see Part 4: “Adult Basic Life Support”) than that recommended in the ECC Guidelines 2000. 1 During the prearrest and postarrest periods, the patient will require support of oxygenation and ventilation with tidal volumes and respiratory rates that more closely approximate normal. Beyond the first minutes of cardiac arrest, tissue hypoxia develops. CPR provides approximately 25% to 33% of normal cardiac output. This low-flow state maintains a small but critical amount of blood flow to the heart and brain, but tissue hypoxia will persist until restoration of effective spontaneous perfusion. Additional factors that contribute to hypoxia include intrapulmonary shunting with microcircula￾tory dysfunction and attendant ventilation-perfusion abnor￾malities. Some patients may also have underlying respiratory disease. Tissue hypoxia leads to anaerobic metabolism and metabolic acidosis. Acid-base imbalance occasionally blunts the beneficial effects of chemical and electrical therapy. To improve oxygenation, healthcare providers should give 100% inspired oxygen (FiO2
1.0) during basic life support and advanced cardiovascular life support as soon as it becomes available. High inspired oxygen tension will tend to maximize arterial oxygen saturation and, in turn, arterial oxygen content. This will help support oxygen delivery (cardiac output arterial oxygen content) when cardiac output is limited. This short-term oxygen therapy does not produce oxygen toxicity. Bag-Mask Ventilation All healthcare providers should be familiar with the use of the bag-mask device for support of oxygenation and ventila￾tion.2– 4 Bag-mask ventilation is particularly helpful during the first few minutes of resuscitation or when placement of an advanced airway is delayed or unsuccessful. Effective bag￾mask ventilation requires adequate training and frequent practice. The desirable components of a bag-mask device are listed in Part 4: “Adult Basic Life Support.” When using a bag￾mask device (ie, no advanced airway is in place), 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.5 This volume of ventilation minimizes the risk of gastric inflation. The rescuer should be sure to open the airway adequately with a chin lift, lifting the jaw against the mask and holding the mask against the face, creating a tight seal. During CPR, give 2 breaths during a brief (about 3 to 4 seconds) pause after every 30 chest compressions. When an advanced airway (eg, endotracheal tube, esophageal-tracheal combitube [Combitube], or laryngeal mask airway [LMA]) replaces the face mask, rescuers should deliver 8 to 10 breaths per minute during CPR. Deliver each breath over about 1 second while chest compressions are delivered at a rate of 100 per minute, and do not attempt to synchronize the compres￾sions with the ventilations. For ventilation of patients with a perfusing rhythm (ie, better pulmonary blood flow than is present during CPR), deliver approximately 10 to 12 breaths per minute (1 breath every 6 to 7 seconds). Deliver these breaths over 1 second when using a mask or an advanced airway. In patients with severe obstructive pulmonary disease and increased resistance to exhalation, providers should try to prevent air trapping that may result in inadvertent generation of intrinsic positive end-expiratory pressure (PEEP), so￾called “auto-PEEP.” In patients with hypovolemia, auto￾PEEP may substantially reduce cardiac output and blood pressure. To prevent this, use lower respiratory rates (eg, 6 to 8 breaths per minute) in these patients, allowing more time for complete exhalation. Bag-mask ventilation can produce gastric inflation with complications, including regurgitation, aspiration, and pneu￾monia. Gastric inflation can elevate the diaphragm, restrict lung movement, and decrease respiratory system compliance.4,6 –9 (Circulation. 2005;112:IV-51-IV-57.) © 2005 American Heart Association. This special supplement to Circulation is freely available at http://www.circulationaha.org DOI: 10.1161/CIRCULATIONAHA.105.166556 IV-51