The rescuer provides ventilation and oxygenation during CPR and peri-arrest stages. The goal for the treatment of a patient in cardiac arrest is to provide and maintain oxygenation and the appropriate expiration of carbon dioxide.

Ventilation and Oxygenation Administration During CPR

Blood flow, rather than arterial oxygen content, is the primary source of oxygen to the heart and brain during CPR. The importance of blood flow is one reason why it is suggested to give chest compressions without any rescue breaths during the first few minutes of CPR, and also why lay rescuers can perform compression-only CPR. 

A single rescuer is advised NOT to interrupt chest compressions for ventilation during the first few minutes of cardiac arrest. When planning to insert an advanced airway, rescuers must ensure the correct timing to prevent a delay in initial CPR and defibrillation, especially for cardiac arrest patients with ventricular fibrillation VF or pVT.

The team must avoid hyperventilation because it is a factor in poor outcomes. Lower ventilation rates can maintain the correct relationship between ventilation and perfusion.

Opening the Airway

In the majority of cases, the airway can be opened using the head tilt-chin lift maneuver. However, if the patient has a suspected spinal injury, rescuers must manually restrict the neck from moving to preserve the cervical spine from further injuries. In those cases, the jaw-thrust maneuver is used to open the airway without compromising the spinal cord. Immobilization devices can potentially interfere with airway patency, and their use is discouraged.

Head-tilt maneuver lifts the tongue and opens the airway.

For witnessed cardiac arrests, especially those with shockable rhythms, the patient briefly has adequate arterial oxygenation. The team should initiate chest compressions and delay ventilations for the first few cycles until the appropriate equipment arrives, such as an AED and airway or ventilation devices. However, for prolonged cardiac arrests, both ventilation and compressions are equally vital to maintaining oxygen levels in the blood and tissues.

Mouth-to-Mouth Rescue Breathing

If the unresponsive patient has a strong pulse but is not breathing, the rescuer must support the patient with ventilation. After activating EMS, the rescuer delivers mouth-to-mouth resuscitation by providing one breath every 6 seconds (10 breaths per minute). 

To provide mouth-to-mouth rescue breaths to a patient, the rescuer first opens the patient’s airway by tilting the forehead backward with one hand and lifting the chin upward with the other. The rescuer should use a barrier device if available. 

The rescuer pinches the patient’s nose closed using the same hand that is tilting the forehead backward, using their mouth to create a tight seal over the patient’s mouth. The rescuer should give 1 breath over 1 second. If correctly performed, there should be a visible chest rise from the patient.

The rescuer is encouraged to take in regular breaths rather than deep breaths while providing mouth-to-mouth ventilation to keep from getting lightheaded. This also prevents overinflation of the patient’s lungs. 

If a rescue breath was given with no discernable chest rise, the airway may not be significantly patent. The rescuer should reposition the patient’s head and perform another head tilt-chin lift maneuver.

Mouth-to-Barrier Device Breathing

There are several commercial barrier devices available to purchase. Many ACLS responders trained in their use choose to carry a barrier device with them in case of emergency. The manufacturer’s recommendations on storage should be followed closely as improper storage may render the device unusable.

If a barrier device is available, rescuers must not delay chest compressions while preparing the device. 

Although not routinely recommended, the trained rescuer may provide mouth-to-mouth breaths without a barrier device if one is not available.

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Related Video: Rescue Breathing for Adults

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Mouth-to-Nose and Mouth-to-Stoma Ventilation

When a situation prevents the provision of mouth-to-mouth ventilation, such as in certain cases of facial trauma, mouth-to-nose ventilation may be used. 

A tracheal stoma provides air passage directly to the trachea after a tracheostomy or laryngectomy. When providing ventilations through a stoma, the rescuer should produce a tight seal using a round pediatric face mask.

Mouth/Bag-to-Stoma

Providing ventilation requires practice, whether using rescue breathing, bag-mask ventilation, or with an advanced airway. The compression-to-ventilation ratio without an advanced airway is 30:2. If an endotracheal tube is in place, rescuers provide one ventilation every 6 seconds. Excessive ventilation rates are associated with poorer outcomes.

Bag-Mask Ventilation

This device remains the mainstay for providing positive pressure ventilation to patients. To deliver breaths from a bag-mask device, the rescuer ensures that the device can deliver at least 600 mL of tidal volume to the patient—enough to produce a chest rise. Breaths should be delivered over 1 second. 

The AHA recommends bag-mask ventilation be delivered by two rescuers. One rescuer is assigned to open the airway and create a seal with the mask over the patient’s mouth and nose. The other rescuer delivers rescue breaths by squeezing the volume of air in the bag over 1 second.

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Related Video: Understanding Bag Valve Mask Usage During CPR

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Related Video: Tips for Bagging

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Basic Airway Adjuncts

When positioning maneuvers do not adequately open and maintain the airway of a patient in respiratory arrest, the team must use basic airway adjuncts.

Oropharyngeal Airways

An oropharyngeal airway (OPA) moves the tongue forward and prevents it from occluding the airway, allowing uninterrupted airflow delivery to the patient. 

Using an inappropriately sized oropharyngeal airway or incorrectly inserting it can move the tongue towards the hypopharynx, causing airway obstruction. To provide the correct size OPA, the rescuer can measure from the tip of the patient’s earlobe to the tip of the nose. 

When inserting the OPA, the rescuer uses their thumb and index finger like a scissor to open the patient’s mouth. The OPA is first inserted upside down so that the tip is pointing toward the roof of the patient’s mouth. It is then rotated 180 degrees during insertion until the flange is resting on the patient’s lips or teeth. 

OPAs should only be used in unconscious patients without a gag reflex. Should the patient begin to gag or retch, the OPA needs to be removed immediately to prevent vomiting or aspiration.

To correctly size an OPA, measure from the corner of the mouth to the angle of the jaw.

Proper Placement of an OPA

Nasopharyngeal Airway

Although the nasopharyngeal airway (NPA) is a more flexible instrument than the OPA, it is also designed to open an unresponsive patient’s airway. Like the OPA, it can be used in conjunction with bag-mask ventilation. 

Nasopharyngeal airways should be used in unresponsive or semi-conscious patients with a gag or coughing reflex. Since it is inserted into the nares, patients with a clenched jaw or injury preventing access to the mouth can benefit from the NPA. The insertion should be done carefully and monitored due to the risk of airway bleeding after NPA placement.⁴⁹

To determine the correct NPA size, the rescuer should measure from the tip of the patient’s earlobe to the tip of their nose. The diameter of the NPA selected should approximate the diameter of the patient’s little finger. 

Before inserting the NPA, the tube should be lubricated first. The right nostril is the typical starting point as it is larger in the majority of the population. The rescuer pulls back on the tip of the patient’s nose gently. The NPA is placed with the bevel pointed towards the nasal septum and inserted along the natural curvature until the flange is seated at the entrance to the nostril. When meeting resistance, the rescuer should not force the tube. Instead, it should be removed, and placement attempted in the left nostril.

CT showing airway being maintained with NPA

Measure NPA from the nostril to the earlobe or tragus.

Suctioning

Mucus, blood, and vomitus can potentially obstruct the airways. Portable or wall-mounted suction devices can be utilized to remove secretions in the airway. 

The suction unit should be powerful enough to provide an airflow of > 40 L/min at the end of the delivery tube and a vacuum of > 300 mm Hg when the tube is clamped. The strength of the vacuum for both devices is adjustable for use in intubated patients. The least amount of pressure needed to clear secretions should be used. Excessive suction pressure can damage the soft tissues of the hypopharynx.

Suctioning requires the use of suction catheters. Soft and flexible silicone catheters should be used in the mouth, nose, or endotracheal tube for deep intratracheal suctioning. Rigid catheters (also known as Yankauer catheters) are capable of suctioning thick secretions but should only be used for suctioning the mouth and oropharynx.

Oral Suctioning of an Intubated Patient with a Rigid Catheter

Open Suctioning of a Patient With a Tracheostomy

Closed Suctioning of an Intubated Patient Using an Inline Suction Device

Advanced Airways

Commonly used advanced airways include endotracheal tubes, laryngeal mask airways, esophageal-tracheal tubes, and laryngeal tubes. Their use depends on the availability and training of the healthcare team. If the team is unable to insert an advanced airway during a respiratory arrest, bag-mask ventilation may suffice.

Ventilation with an Advanced Airway

ACLS teams must practice inserting advanced airways such as the endotracheal (ET) tube. They should understand that the risks and benefits of pausing chest compressions to intubate the cardiac arrest patient depend on the patient’s condition and the ACLS team’s skill.

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Studies do not report any benefits or disadvantages of placing an advanced airway earlier or later in resuscitation.⁵⁰ The decision for when to insert an airway is left to the team leader’s discretion. 

Intubating a patient can be done while CPR is ongoing, but chest compressions cannot be interrupted. If intubation disturbs chest compressions, advanced airway placement should be postponed unless the patient fails to exhibit improvement or does not demonstrate signs of ROSC. A bag-mask device can provide adequate ventilation while performing CPR. 

After successful insertion of an advanced airway, the ventilation provider should deliver one breath every 6 seconds while the chest compressor continues compressions at a rate of 100–120/min without any pauses. The compressor and ventilator shift roles after every 2-minute cycle to avoid fatigue.

Advanced Airway Placement Choice

Either a bag-mask or an advanced airway is suitable to provide oxygenation and ventilation when resuscitating a cardiac arrest patient. There are no studies that favor the use of endotracheal intubation over bag-mask ventilation.^51,52

If there is no improvement in the patient’s condition after several minutes of resuscitation, the team leader may order the insertion of an advanced airway as part of a step-wise approach in the treatment of the cardiac arrest patient. A trained member of the resuscitation team who knows how to insert an advanced airway then inserts an ET tube or a supraglottic airway device.

Laryngeal Mask Airway (LMA)

Another Laryngeal Mask Airway (LMA)

Laryngeal Tube Kit

Proper Oral Intubation Technique

Endotracheal Tube Placement

The task of inserting an endotracheal (ET tube) must be familiar to all resuscitation teams. Any member of the team may be required to either insert the ET tube or assist someone who will. The steps in endotracheal intubation are listed as follows:

• All necessary equipment is gathered and assembled.
• The patient is hyperoxygenated.
• Endotracheal intubation is performed.
• The cuff on the tube is inflated.
• The ET tube is then attached to the ventilation bag.
• Successful placement of the ET tube is confirmed via at least two methods, e.g., physical examination and continuous waveform capnography (or other methods such as CO₂ detectors or chest X-ray).
• The tube is measured at the teeth or lips and secured in place.
• The patient is monitored for signs of possible tube displacement.

Continuous waveform capnography is recommended to confirm the correct placement of an ET tube. Other devices, including nonwaveform CO₂ detectors such as an esophageal detector device, colorimetric devices, or ultrasound, may be utilized if continuous waveform capnography is unavailable.

If a previously stable patient suddenly deteriorates after successful endotracheal intubation, the responder must immediately evaluate the ET tube placement. The DOPE mnemonic can be used to diagnose the problem. 

DOPE stands for: 

• Displaced tube
• Obstructed tube
• Pneumothorax
• Equipment failure

A soft plastic foley clamp can be used to help keep IV lines organized and safe while monitoring the intubated patient.

Oxygen Dose During CPR

Supplementary oxygen should be given at the highest setting (100%) to provide the maximal available inspired oxygen dose. The theory behind this is to increase the oxygen content of arterial blood to mitigate ischemic effects in cardiac arrest. The aim is to restore the heart’s ability to resume its function and preserve the brain’s function to improve neurologic outcomes.

Passive Oxygen Delivery During CPR

The use of airway adjuncts such as a nonrebreather mask, oropharyngeal airway, or supraglottic airway can be attached to a high-flow oxygen delivery system to provide oxygen insufflation. During CPR, as the chest recoils, a certain amount of oxygen will enter the lungs and passively into the bloodstream.

Passive Oxygenation vs. Positive Pressure Ventilation During CPR

Passive oxygen administration is the provision of oxygen without providing any pressure. This can be accomplished through a nonrebreather mask, an oropharyngeal airway, or a supraglottic airway. Studies have compared passive oxygen administration with positive pressure ventilation via bag-mask ventilation or ET tube ventilation. Results showed that passive oxygen administration is associated with lower partial pressures of arterial carbon dioxide, but there was no improvement in outcomes.^53,54 

Another study assessed the administration of high-flow oxygen delivery, which was part of a resuscitation bundle by EMS, and it showed an improvement in survival with favorable neurologic outcomes.⁵⁵ This study included only patients with witnessed arrest with VF or pulseless ventricular tachycardia (pVT). A review on the topic published in 2018 again confirmed that continuous flow insufflation of oxygen does not hold an advantage for ROSC or survival in OHCA when compared to standard ventilation techniques.⁵⁶

The guidelines do not recommend the routine use of passive ventilation techniques during CPR with the present data. However, if well-trained EMS systems of care have bundled its use with minimal interruptions in chest compressions, then it may be acceptable for witnessed shockable OHCA.

Postintubation Airway Management

There is a risk of ET tube movement or dislodgement after insertion. The tube should be secured with tape or commercial devices that anchor it in place. The team must record the depth of the tube as marked at the front teeth after insertion and securing it in place. Applying adhesives to anchor the tube in place must not cause compression of the patient’s neck, which can obstruct circulation to and from the brain. 

After performing these procedures, a chest X-ray can be used to confirm the ET tube positioned just above the carina. However, obtaining an X-ray to confirm placement must not interfere with the resuscitation process.

X-Ray view of ET tube properly placed above the carina

X-ray view of right mainstem intubation with white markings on the left chest indicating no air movement

Automatic Transport Ventilators

Automatic transport ventilators (ATVs) are useful for allowing healthcare teams to perform other tasks while providing adequate ventilation and oxygenation. ATVs can only be applied to patients with an advanced airway in place. Teams must always have a backup device such as a bag-mask device in case the ATV fails.

Adjusting Patient Ventilator During Flight

Suctioning an ET Tube

When the team has established an ET tube, it is essential to suction the tube when necessary to maintain patency. Before suctioning, the patient should be assessed to avoid unnecessary suctioning. Even though suctioning helps remove secretions, it is also important to remember that suctioning removes oxygen from the airways.

Indications for suctioning during resuscitation might include:

• Audible secretions
• Decreased oxygen saturation levels
• Increased PaCO₂ levels
• Increased respiratory rate 
• Cyanosis
• Suspected ET tube obstruction
• Decreased or absent breath sounds

The steps for suctioning the ET tube can apply to the suctioning of any advanced airway. These steps include:

1. The patient is assessed to determine if suctioning is needed.
2. Appropriate equipment is prepared.
3. Suction pressure is set according to facility protocol.
4. The appropriate size suction catheter is determined based on double the ET tube size, e.g., a 7.0 mm ET tube would indicate the use of a suction catheter no larger than 14-French. 
5. Steps are taken to preoxygenate the patient.
6. The team wears personal protective equipment.
7. Suction depth is evaluated to determine the depth equivalent to approximately 1 cm beyond the length of the ET tube.
8. The suction catheter is removed from its sheath and inserted into the ET tube to the predetermined depth. Suction should NOT be applied during insertion.
9. As the catheter is being removed, suction is applied, but not for more than 10 seconds.
10. Oxygenation follows suctioning. A recovery period is allowed between suctioning passes, and no more than three passes should be performed during any suctioning session.
11. The patient is monitored following suction to determine success.

Closed systems are ideal because the suction setup is always ready. Closed systems avoid circuit disconnections and also protect the team from infectious exposure.

Closed (In-Line) Suction Device