In the high-stress prehospital environment, managing intubated patients effectively is crucial for their survival and long-term outcomes. While bag-valve-mask (BVM) devices are essential in emergencies, their prolonged use can lead to significant complications, particularly under the pressures of emergency calls. This article discusses why intubated patients in the prehospital setting should be transitioned to mechanical ventilators as soon as possible. We will explore the importance of humidifying and warming the air (with a disclaimer), maintaining adequate inspiratory pressure, ensuring alveolar compliance, delivering appropriate tidal volumes, and avoiding complications such as barotrauma and alveolar collapse. Additionally, we will discuss specific ventilator settings that help mitigate these complications, especially considering the stresses faced by prehospital providers. Furthermore, we will highlight how investing in ventilators can free up a provider’s hands, allowing them to focus on other critical aspects of patient care.
The Impact of Stress on BVM Use
Emergency calls in the prehospital environment are inherently stressful, often leading to an adrenaline surge in providers. This sympathetic response can result in the tendency to over-inflate, over-ventilate, and over-pressurize the air supplied by the BVM. These actions, while well-intentioned, can cause significant harm to patients. Mechanical ventilators offer a solution by providing consistent, controlled ventilation, mitigating the risks associated with manual BVM use under stress.
Humidifying and Warming the Air
When patients are intubated, the natural humidification and warming functions of the upper airway are bypassed. Delivering dry, cold air can lead to mucosal drying, increased secretions, and potential blockages of the endotracheal tube (ETT). Mechanical ventilators equipped with humidification systems provide warm, moist air, reducing these risks. This is crucial for maintaining mucosal integrity and preventing complications associated with prolonged intubation.
Disclaimer: Not all transport or emergency ventilators have humidification options, so providers must be aware of their equipment’s capabilities and the potential need for alternative humidification methods.
Maintaining Adequate Inspiratory Pressure
Peak Inspiratory Pressure (PIP)
Maintaining the correct inspiratory pressure is essential to prevent trauma to the airway and lungs. Excessive pressure can cause barotrauma, leading to alveolar rupture and pneumothorax. Mechanical ventilators allow precise control of Peak Inspiratory Pressure (PIP), which is the maximum pressure applied during inhalation. By setting an appropriate PIP, usually below 30 cm H2O, the risk of barotrauma can be minimized. This control is particularly important in stressful situations where providers may unintentionally apply excessive pressure using a BVM.
Ensuring Alveolar Compliance
Plateau Pressure (Pplat)
Alveolar compliance, or the ability of the alveoli to expand and contract with each breath, is critical for effective gas exchange. Mechanical ventilators can measure and control Plateau Pressure (Pplat), which reflects the pressure in the alveoli at the end of inspiration when airflow is momentarily paused. Maintaining a Pplat below 30 cm H2O helps ensure that the alveoli are not over-distended, thus reducing the risk of volutrauma and promoting optimal compliance.
Delivering Appropriate Tidal Volumes
Tidal Volume (VT) and Respiratory Rate (RR)
The correct volume of air delivered with each breath (tidal volume) is crucial to avoid volutrauma. Mechanical ventilators allow precise adjustment of Tidal Volume (VT), typically set at 6-8 mL/kg of predicted body weight. This ensures that patients receive the appropriate volume of air without over-distension of the lungs. Additionally, the Respiratory Rate (RR) can be set to match the patient’s metabolic needs, typically between 12-20 breaths per minute for adults. This helps prevent hyperventilation and breath stacking, common issues during stressful situations where manual BVM use can lead to excessive ventilation rates.
Avoiding Complications: Barotrauma and Alveolar Collapse
Positive End-Expiratory Pressure (PEEP)
Barotrauma and alveolar collapse are significant risks when using BVM for prolonged periods. The insertion of an ETT reduces the body’s natural ability to apply PEEP, which keeps the alveoli open at the end of each breath. Mechanical ventilators can provide consistent and adjustable PEEP, usually set between 5-10 cm H2O, to maintain alveolar patency and prevent collapse. This is critical for ensuring continuous gas exchange and preventing hypoxia.
Freeing Up Providers’ Hands
Most prehospital agencies operate with a two-person configuration, making efficient use of resources essential. Investing in ventilators not only enhances patient safety but also frees up one of the providers who would otherwise be manually operating the BVM. This allows the provider to focus on other critical aspects of patient care, such as administering medications, managing intravenous lines, or performing other necessary interventions. This improved efficiency can significantly enhance the overall quality of care delivered in the prehospital setting.
Detailed Ventilator Settings to Reduce Complications
Peak Inspiratory Pressure (PIP)
- Purpose: Prevents barotrauma by limiting the maximum pressure during inhalation.
- Setting: Typically set below 30 cm H2O.
- Benefit: Reduces the risk of lung injury due to excessive pressure.
Plateau Pressure (Pplat)
- Purpose: Measures alveolar pressure and helps assess lung compliance.
- Setting: Maintained below 30 cm H2O.
- Benefit: Prevents alveolar over-distension and promotes optimal compliance.
Tidal Volume (VT)
- Purpose: Ensures appropriate lung inflation without over-distension.
- Setting: 6-8 mL/kg of predicted body weight.
- Benefit: Reduces the risk of volutrauma by delivering precise volumes of air.
Respiratory Rate (RR)
- Purpose: Matches the patient’s metabolic needs and prevents hyperventilation.
- Setting: Typically 12-20 breaths per minute for adults.
- Benefit: Prevents breath stacking and ensures adequate ventilation without hyperventilation.
Positive End-Expiratory Pressure (PEEP)
- Purpose: Maintains alveolar patency and prevents collapse.
- Setting: Typically 5-10 cm H2O.
- Benefit: Enhances gas exchange and prevents hypoxia by keeping the alveoli open.
Call to Action for Prehospital Providers
To ensure the highest standard of care, it is imperative for prehospital providers to become proficient in the use of mechanical ventilators. Agencies should invest in these devices to improve patient safety and outcomes. The transition from BVM to mechanical ventilation can significantly reduce the risks of barotrauma, alveolar collapse, and other complications associated with improper ventilation techniques, particularly under the stress of emergency calls. Furthermore, the use of ventilators frees up a provider, enabling them to focus on other essential aspects of patient care.
By prioritizing the use of mechanical ventilators, prehospital care can be greatly enhanced, leading to better patient outcomes and a higher standard of care in emergency medical services. Prehospital providers must undergo regular training to stay updated with the latest advancements in mechanical ventilation and be prepared to deliver optimal care in the field.
In conclusion, while BVM devices are essential for initial resuscitation and short-term ventilation, mechanical ventilators provide superior control over airway pressures, tidal volumes, and humidification (when available), making them indispensable for the prolonged care of intubated patients. Prehospital providers must be trained in the use of these devices, and agencies should prioritize their availability to ensure the highest standard of care and improve patient safety, particularly in the high-stress environment of emergency medical services.
Disclaimer: AGC Med does not endorse the use of any specific product. Any products shown in this post are for demonstration purposes only.
