Lesson 6 – Special Considerations in Artificial Ventilation

Special Populations in Ventilation

Special populations require specific ventilation adjustments. These include pediatric, geriatric, trauma, cardiac arrest, pregnant, COPD, asthmatic, and drowning patients. Each group presents unique challenges and understanding these differences is key for improving patient outcomes.

Pediatric Ventilation

Pediatric patients have higher normal respiratory rates and smaller tidal volumes compared to adults. This means they require more frequent ventilations but with less volume per breath. Be cautious of gastric distension, which can occur more easily and impair ventilation. Always use appropriately sized equipment such as masks, bags, and airway adjuncts. Children decompensate quickly, so maintaining adequate oxygenation is crucial. Refer to pediatric reference cards or tapes for age-appropriate rates and volumes.

Pediatric Airway Anatomy

Children have several anatomical differences that affect ventilation: a larger occiput that can flex the neck when lying flat and potentially obstruct the airway, a higher and more anteriorly positioned larynx, a larger tongue relative to the oral cavity which can obstruct the airway, and a softer and more compliant trachea that is at risk of collapsing under excessive pressure. Additionally, their overall airway diameter is narrower, so even minor swelling can impair airflow.

Geriatric Ventilation

Geriatric patients often have decreased lung compliance, meaning higher pressures are needed to achieve adequate tidal volumes. Osteoporosis increases the risk of rib fractures during chest compressions or aggressive BVM use. Decreased gag reflex and esophageal tone heighten the risk of aspiration. Comorbidities such as COPD or heart failure can complicate ventilation. Medications like beta-blockers or sedatives can affect respiratory drive and response to treatment. Always consider the patient's clinical picture and comorbidities when ventilating geriatric patients.

Trauma Ventilation

When ventilating trauma patients, always maintain C-spine precautions and prefer the jaw-thrust maneuver over head tilt-chin lift. Be cautious of pneumothorax, especially in chest trauma. Unequal chest rise or sudden difficulty ventilating may indicate pneumothorax. Facial or neck trauma can complicate ventilation and should be carefully monitored. External bleeding must be controlled, as significant blood loss can lead to shock and impact tissue oxygenation. In patients with suspected head injuries, avoid hyperventilation, as it can decrease cerebral blood flow; aim for normal EtCO2 levels unless directed otherwise.

Cardiac Arrest Ventilation

In single-rescuer CPR, use a 30:2 compression-to-ventilation ratio. For multiple rescuers and an advanced airway, provide continuous chest compressions with asynchronous ventilations at a rate of 10 breaths per minute. Avoid excessive ventilation as it can increase intrathoracic pressure and reduce venous return to the heart. Some protocols recommend passive oxygenation techniques in the early minutes of CPR. High-quality chest compressions remain the priority – ensure they are deep, fast, and allow full chest recoil.

Pregnant Patient Ventilation

In pregnant patients, especially in the third trimester, place the patient in a left lateral tilt position to relieve pressure on the inferior vena cava and improve venous return. Pregnant women have higher oxygen demand and lower functional residual capacity, which can lead to rapid desaturation. They are also at higher risk for aspiration due to decreased lower esophageal sphincter tone and increased abdominal pressure. In cardiac arrest, early activation of resources for a potential perimortem C-section can improve survival chances for both the mother and fetus.

COPD Ventilation

Patients with Chronic Obstructive Pulmonary Disease (COPD) are at risk for air trapping due to obstructed airways. Allow for a longer expiratory phase when ventilating. Mild hypercapnia is often normal in these patients, so do not aim for normal EtCO2 unless directed by medical control. Bronchodilators can help improve air movement. Non-invasive positive pressure ventilation (BiPAP or CPAP) may be helpful. These patients are also at higher risk for pneumothorax, especially when using positive pressure ventilation.

Asthma Exacerbation Ventilation

In asthma exacerbations, dynamic hyperinflation can occur, where air is trapped in the lungs due to airway constriction. Allow for a longer expiratory phase when ventilating and slow your ventilation rate. Bronchodilators are essential, and inline nebulizers should be considered when ventilating with a BVM. Be vigilant for signs of tension pneumothorax in severe asthma cases. If available, CPAP may be beneficial for some asthma patients. Severe asthmatics may have altered mental status due to hypercapnia and may need to be prepared for potential respiratory arrest.

Drowning Victim Ventilation

For drowning victims, the primary issue is often hypoxia, so start with ventilations as the priority. Be prepared for vomiting, which is common in drowning victims, and have suction available. CPAP may be useful for conscious patients with respiratory distress. Secondary drowning can occur, where pulmonary edema develops hours after the initial incident. Maintaining body temperature is critical, especially in cold water drownings – active rewarming may be necessary. With prompt, appropriate care, many drowning victims have excellent outcomes.

Secondary Drowning

Secondary drowning occurs when pulmonary edema develops hours after the initial drowning incident. It can cause delayed respiratory distress, which is crucial to monitor for in drowning victims.

Ventilation in Trauma

When ventilating trauma patients, always secure C-spine precautions, favoring the jaw-thrust maneuver over head tilt-chin lift. Monitor for pneumothorax in chest trauma, as unequal chest rise or difficulty ventilating may indicate its presence. Facial or neck injuries may complicate airway management. Control external bleeding, as blood loss can lead to shock, impacting oxygenation.

Ventilation in Cardiac Arrest

In cardiac arrest, the first priority is high-quality chest compressions. For single-rescuer CPR, maintain a 30:2 compression-to-ventilation ratio. With advanced airways, provide continuous chest compressions and asynchronous ventilations at a rate of 10 breaths per minute. Avoid excessive ventilation to prevent increased intrathoracic pressure and decreased venous return to the heart