When An Advanced Airway Is In Place Chest Compressions

When an advanced airway is in place, chest compressions become a critical component of cardiopulmonary resuscitation (CPR) that require precise execution to ensure optimal patient outcomes. The insertion of advanced airways like endotracheal tubes or supraglottic airways modifies traditional CPR protocols, emphasizing uninterrupted chest compressions synchronized with ventilations. This article delves into the nuances of chest compressions when an advanced airway is in place, exploring the techniques, importance, scientific underpinnings, and best practices that practitioners must master to provide effective resuscitation.

Understanding the Role of Advanced Airways in CPR

Advanced airways are crucial interventions in advanced cardiac life support (ACLS) that ensure a secure and patent airway, allowing for effective oxygenation and ventilation during resuscitation. Unlike basic airway maneuvers, which may be sufficient for spontaneous breathing or rescue breaths, advanced airways provide a more reliable and controlled method for delivering oxygen to the lungs, particularly in cases of prolonged arrest or when basic methods prove inadequate.

Types of Advanced Airways

• Endotracheal Intubation (ETI): This involves inserting a tube through the mouth or nose into the trachea, providing a direct route for ventilation. ETI requires skilled practitioners and is often considered the gold standard for airway management due to its ability to protect against aspiration and deliver precise tidal volumes.
• Supraglottic Airways (SGA): These devices, such as laryngeal mask airways (LMAs) and esophageal-tracheal Combitubes, are inserted blindly into the pharynx to provide ventilation without entering the trachea directly. SGAs are easier to insert than endotracheal tubes and can be used by a wider range of healthcare providers.

Advantages of Advanced Airways

• Improved Oxygenation and Ventilation: Advanced airways allow for the delivery of consistent and controlled breaths, ensuring adequate oxygenation and ventilation, which are vital for maintaining cellular viability during cardiac arrest.
• Aspiration Prevention: Endotracheal intubation provides a secure seal that prevents gastric contents from entering the lungs, reducing the risk of aspiration pneumonia.
• Medication Administration: Certain medications, such as epinephrine, lidocaine, and atropine, can be administered via the endotracheal tube if intravenous access is not immediately available.
• Continuous Monitoring: Advanced airways facilitate continuous monitoring of exhaled carbon dioxide (EtCO2), providing real-time feedback on ventilation effectiveness and perfusion.

The Modified CPR Protocol with Advanced Airway

Once an advanced airway is secured, the traditional 30:2 compression-to-ventilation ratio is abandoned in favor of continuous chest compressions with asynchronous ventilations. This modification is based on evidence that uninterrupted chest compressions improve coronary perfusion pressure and increase the likelihood of successful resuscitation.

Continuous Chest Compressions

• Rate: The recommended compression rate remains 100-120 compressions per minute. This rate ensures adequate blood flow to the heart and brain.
• Depth: Compressions should be performed to a depth of at least 2 inches (5 cm) but no more than 2.4 inches (6 cm) in adults. Adequate depth is crucial for generating sufficient cardiac output.
• Recoil: Full chest recoil is essential after each compression to allow the heart to refill with blood. Incomplete recoil can reduce the effectiveness of compressions.
• Minimizing Interruptions: Interruptions in chest compressions should be minimized to maintain consistent blood flow. Frequent interruptions can significantly decrease the chances of survival.

Asynchronous Ventilations

• Rate: Ventilations are typically delivered at a rate of 8-10 breaths per minute. This rate is sufficient to provide adequate oxygenation without interfering with chest compressions.
• Volume: Each breath should be delivered over 1 second, with sufficient volume to produce visible chest rise. Excessive ventilation can lead to gastric inflation and increased intrathoracic pressure, which can impair venous return and reduce cardiac output.
• Timing: Ventilations should be delivered independently of chest compressions, without pausing compressions. This asynchronous approach ensures continuous blood flow and oxygen delivery.

Techniques for Effective Chest Compressions

Performing effective chest compressions requires proper technique and adherence to established guidelines. Here are key considerations:

Hand Placement

• Adults: Place the heel of one hand on the lower half of the sternum, between the nipples. Place the other hand on top of the first, interlacing the fingers. Ensure that pressure is applied vertically to the sternum.
• Children: For smaller children, use one hand to perform compressions, while for larger children, use the same technique as for adults.
• Infants: Use two fingers (index and middle fingers) to compress the sternum, just below the nipple line. Alternatively, use the two-thumb encircling hands technique, especially when two rescuers are available.

Body Positioning

• Rescuer Position: Position yourself directly above the patient, with your shoulders aligned over your hands. This allows you to use your body weight to deliver effective compressions.
• Surface: Ensure that the patient is lying on a firm, flat surface. A soft surface can absorb the force of compressions and reduce their effectiveness.

Compression Technique

• Straight Arms: Keep your arms straight and use your upper body weight to compress the chest. Avoid bending your elbows, which can lead to fatigue and ineffective compressions.
• Consistent Rhythm: Maintain a consistent rhythm and avoid sudden or jerky movements. Smooth, rhythmic compressions are more effective at generating blood flow.
• Avoid Leaning: Avoid leaning on the chest between compressions, as this can prevent full chest recoil and reduce the effectiveness of subsequent compressions.

Scientific Basis for Continuous Chest Compressions

The shift towards continuous chest compressions with asynchronous ventilations is grounded in extensive research demonstrating its superiority over traditional CPR methods.

Coronary Perfusion Pressure (CPP)

CPP is the difference between aortic diastolic pressure and right atrial diastolic pressure. It is a critical determinant of myocardial blood flow during CPR. Studies have shown that continuous chest compressions increase CPP by maintaining higher aortic diastolic pressures, which in turn improve myocardial oxygen delivery.

Cerebral Blood Flow

Maintaining adequate cerebral blood flow is crucial for preventing neurological damage during cardiac arrest. Continuous chest compressions have been shown to improve cerebral perfusion by sustaining consistent blood flow to the brain, reducing the risk of hypoxic-ischemic injury.

Animal Studies

Animal studies have provided valuable insights into the benefits of continuous chest compressions. These studies have demonstrated that uninterrupted compressions result in higher rates of return of spontaneous circulation (ROSC), improved survival, and better neurological outcomes compared to traditional CPR with pauses for ventilation.

Human Studies

Clinical trials in humans have confirmed the findings from animal studies. Several studies have shown that continuous chest compressions are associated with higher rates of ROSC, improved survival to hospital discharge, and better neurological function in survivors of cardiac arrest.

Integrating Monitoring Technologies

Advanced monitoring technologies play a crucial role in optimizing chest compression effectiveness and guiding resuscitation efforts.

End-Tidal Carbon Dioxide (EtCO2) Monitoring

EtCO2 monitoring provides real-time feedback on the effectiveness of chest compressions and ventilation. A sudden increase in EtCO2 levels can indicate ROSC, while consistently low EtCO2 levels may suggest inadequate chest compressions or poor perfusion.

• Normal Range: During CPR, an EtCO2 level of at least 10 mmHg is generally considered acceptable, with higher levels indicating better perfusion.
• ROSC Indication: A sudden increase in EtCO2 to 35-40 mmHg or higher is a strong indicator of ROSC.

Arterial Blood Pressure Monitoring

Invasive arterial blood pressure monitoring can provide continuous assessment of blood pressure during CPR, allowing for more precise titration of vasopressors and other medications.

• Target Blood Pressure: The goal during CPR is to achieve a systolic blood pressure of at least 90 mmHg and a diastolic blood pressure of at least 40 mmHg.

Impedance Threshold Device (ITD)

An ITD is a valve that is placed between the endotracheal tube and the ventilation bag. It restricts airflow into the chest during recoil, creating a vacuum that enhances venous return and improves cardiac output. Studies have shown that ITDs can improve survival rates when used in conjunction with continuous chest compressions.

Addressing Common Challenges and Pitfalls

Despite the evidence supporting continuous chest compressions, several challenges and pitfalls can hinder their effectiveness.

Fatigue

Performing high-quality chest compressions is physically demanding, and rescuer fatigue can significantly reduce compression depth and rate. To mitigate fatigue:

• Teamwork: Rotate rescuers every 2 minutes to maintain compression quality.
• Mechanical Devices: Consider using mechanical chest compression devices, such as the LUCAS device or AutoPulse, for prolonged resuscitation efforts.

Interruptions

Frequent interruptions in chest compressions can decrease CPP and reduce the likelihood of ROSC. To minimize interruptions:

• Streamline Procedures: Plan and coordinate interventions to minimize pauses in compressions.
• Clear Communication: Use clear and concise communication to coordinate actions and avoid unnecessary interruptions.

Hyperventilation

Excessive ventilation can lead to gastric inflation, increased intrathoracic pressure, and impaired venous return. To avoid hyperventilation:

• Monitor Chest Rise: Deliver breaths slowly over 1 second, with sufficient volume to produce visible chest rise.
• Ventilation Rate: Maintain a ventilation rate of 8-10 breaths per minute.

Incorrect Hand Placement

Incorrect hand placement can result in ineffective compressions and potential injuries. To ensure proper hand placement:

• Landmark Identification: Clearly identify the correct landmark on the sternum before initiating compressions.
• Visual Confirmation: Visually confirm hand placement with each rescuer change.

Special Considerations

Certain patient populations and clinical scenarios require special considerations when performing chest compressions with an advanced airway.

Pregnancy

In pregnant patients, manual left uterine displacement (LUD) should be performed during chest compressions to relieve pressure on the inferior vena cava and improve venous return. If LUD is not effective, consider manual displacement.

Obesity

In obese patients, the increased chest mass may require greater force to achieve adequate compression depth. Use anatomical landmarks carefully to ensure correct hand placement.

Trauma

In patients with suspected or confirmed trauma, spinal stabilization should be maintained during chest compressions. Log-roll the patient as a unit to minimize spinal movement.

Hypothermia

Hypothermic patients may require prolonged resuscitation efforts, as the protective effects of hypothermia can extend the window of viability. Continue chest compressions until the patient is rewarmed to a normothermic temperature.

Training and Education

Effective implementation of continuous chest compressions requires comprehensive training and ongoing education for healthcare providers.

Basic Life Support (BLS)

BLS training should emphasize the importance of high-quality chest compressions and early defibrillation. Participants should be trained in proper hand placement, compression depth and rate, and minimizing interruptions.

Advanced Cardiac Life Support (ACLS)

ACLS training should cover the principles of advanced airway management, including endotracheal intubation and supraglottic airway insertion. Participants should be trained in the modified CPR protocol with continuous chest compressions and asynchronous ventilations.

Continuing Education

Regular continuing education is essential to reinforce knowledge and skills related to chest compressions and advanced airway management. Simulation-based training can provide valuable opportunities to practice these skills in a realistic setting.

The Future of Chest Compression Techniques

The field of resuscitation science is constantly evolving, with ongoing research aimed at improving chest compression techniques and patient outcomes.

Mechanical Chest Compression Devices

Continued advancements in mechanical chest compression devices may lead to more widespread adoption of these devices in clinical practice. Future devices may incorporate feedback mechanisms to optimize compression depth and rate.

Adjunctive Therapies

Research is ongoing to evaluate the potential benefits of adjunctive therapies, such as extracorporeal membrane oxygenation (ECMO) and targeted temperature management (TTM), in conjunction with continuous chest compressions.

Personalized Resuscitation

Future resuscitation protocols may be tailored to individual patient characteristics and clinical scenarios. This personalized approach could involve using advanced monitoring technologies to optimize chest compression techniques and guide medication administration.

Conclusion

When an advanced airway is in place, chest compressions take on a specialized role that demands a nuanced understanding and precise execution. The transition to continuous chest compressions with asynchronous ventilations is a cornerstone of modern resuscitation, supported by robust scientific evidence demonstrating improved outcomes. Mastering the techniques, integrating monitoring technologies, and addressing common challenges are crucial for healthcare providers to enhance their resuscitation efforts. As the field evolves, ongoing training, research, and the adoption of innovative technologies will further refine chest compression techniques, ultimately improving survival rates and neurological outcomes for patients experiencing cardiac arrest. The ability to deliver high-quality, uninterrupted chest compressions in conjunction with advanced airway management is a life-saving skill that every healthcare professional must strive to perfect.