In GI endoscopy, the rising use of propofol sedation intensifies the challenge of hypoxemia. To ensure patient safety, diverse airway equipment is imperative, surpassing traditional methods like standard nasal cannulas.
Preventing life-threatening hypoxemia during GI endoscopy is paramount. Recognizing the limitations of conventional approaches highlights the critical role of specialized airway equipment, particularly continuous positive airway pressure (CPAP) devices.
Exploring the diverse landscape of airway tools tailored for GI endoscopy requires swift comprehension of their merits and drawbacks. This exploration emphasizes their varied physio-mechanical mechanisms, focusing on their collective contribution to maintaining airway patency and delivering high-flow oxygen.
In navigating this evolving landscape, embracing diverse airway equipment becomes a catalyst for innovation. This concise overview sets the stage for a deeper exploration into the pivotal role played by different airway devices in reshaping and safeguarding innovation in GI endoscopy.
High-Flow Nasal Cannula
Settings for Tubeless Anesthesia in GI Endoscopy: The application of the HFNC device in tubeless anesthesia for GI endoscopy involves initiating the oxygen flow rate at 4 L/min, progressively increasing to 15 L/min. This technique is especially effective when denitrogenation of the lungs, achieving 100% oxygen saturation with a tight-fitting face mask, precedes the administration of sedative agents.
Indications: HFNC in tubeless anesthesia for GI endoscopy is well-suited for patients undergoing routine and advanced procedures without the need for endotracheal intubation. It is particularly beneficial for individuals with obstructive sleep apnea, morbid obesity, chronic obstructive airway disease (COPD), pulmonary fibrosis, and those undergoing prolonged, complicated advanced endoscopic procedures.
- Prolonged Safe Apnea Time: HFNC extends the safe apnea time, providing optimal conditions for procedures without the need for intubation.
- Reduced Dead Space: HFNC, unlike noninvasive ventilation, minimizes dead space, enhancing efficiency during tubeless anesthesia.
- Positive Airway Pressure Effect: HFNC contributes to positive end-expiratory pressure, reducing the work of breathing and enhancing oxygenation, especially in patients with alveolar filling diseases.
- Adverse Effects: Potential adverse effects include rhinalgia, pharyngalgia, xeromycteria, headache, and barotrauma (e.g., pneumothorax and subcutaneous emphysema).
- Cost Considerations: The cost of HFNC devices may be a factor, especially considering changing insurance remuneration and decreasing payments for procedures.
- Study Limitations: Some studies demonstrate HFNC effectiveness, but concerns have been raised about methodology and ethical aspects, questioning the delayed implementation of interventions during desaturation.
Modified Bite Blocks
Goudra’s Bite Block: Goudra’s bite block, although not yet available on the market, introduces a unique approach by combining the elements of a face mask and airway within the endoscopy bite block. This design aims to deliver 100% oxygen to the laryngeal inlet, potentially providing continuous positive airway pressure (CPAP) and minimizing anatomical dead space. The device, connected to a Mapleson breathing system, offers the possibility of controlled positive pressure ventilation. As of now, its availability for clinical use remains pending.
Oxygen Providing Bite Blocks:
- Respa Oxygen Delivery Bite Block: Respa, a recent addition to the Endoscopy family of bite blocks in the United States, addresses the challenge of securing nasal cannulas during procedures. While its effectiveness and potential adverse effects are yet to be documented in studies, it presents a practical solution for oxygen cannula placement and retention during upper GI endoscopy under sedation.
- OxyShieldTM: OxyShieldTM, another endoscopic bite block with similar capabilities, ensures constant and guaranteed supplemental oxygen delivery. While the effectiveness of these devices in reducing hypoxemia incidence has not been extensively studied, their role in seamlessly integrating oxygen supplementation without significant practice changes makes them promising tools for tubeless anesthesia in GI endoscopy.
These modified bite blocks showcase innovative approaches to oxygen delivery, potentially enhancing the efficacy of tubeless anesthesia in GI endoscopy. While further research is needed to establish their effectiveness and safety, these devices offer practical solutions for oxygen supplementation during procedures without significant procedural adaptations.
Procedural Oxygen Mask® (POM®): The Procedural Oxygen Mask® (POM®) plays a crucial role in enhancing oxygenation during GI endoscopy by elevating oxygen concentration at the laryngeal inlet. Its design, featuring a self-sealing central aperture for endoscope insertion and an opening for gas sampling tubing, facilitates end-tidal carbon dioxide monitoring. Both the original POM® and an improvised version provide cost-effective alternatives to improve procedural safety and monitoring.
Endoscopy Face Masks:
- DEAS and VBM Endoscopic Masks: These modified face masks integrate intubation ports for upper GI endoscopy and bronchoscopy, aiming to provide positive pressure ventilation. However, their complexity and impracticality, especially for patients with airway challenges like obstructive sleep apnea, pose significant limitations.
- Endoscopic Nasal Mask: The endoscopic nasal mask, with its intricate design featuring a soft cushion, nasal aperture, and flexible connector, offers multifunctionality. While it can deliver oxygen via positive pressure, its complexity demands expertise for successful application.
Advantages and Disadvantages:
- Enhanced Oxygenation: These advanced airway devices contribute to improved oxygenation during GI endoscopy procedures.
- Monitoring Capability: Certain devices, like the POM®, enable end-tidal carbon dioxide monitoring, enhancing procedural safety.
- Cost-Effective Alternatives: Improvised versions of devices, such as the POM®, offer cost-effective solutions for achieving procedural objectives.
- Complexity and Impracticality: Face masks like DEAS and VBM Endoscopic Masks, despite their positive pressure ventilation capabilities, are criticized for their complexity and impracticality, particularly in patients with airway challenges.
- Expertise Requirement: The endoscopic nasal mask’s intricate design demands expertise for successful application, potentially limiting its widespread use.
Advanced Airway Devices
Employing advanced airway devices has become a hallmark in achieving tubeless anesthesia, eliminating the need for traditional intubation methods. Let’s delve into several innovative devices and techniques that revolutionize airway management during GI endoscopic procedures.
Nasopharyngeal Airway: A simple yet effective tool in tubeless anesthesia is the nasopharyngeal airway. At the forefront is the experience from the Hospital of the University of Pennsylvania, showcasing its success over a decade. Following appropriate preoxygenation, propofol administration, and mindful insertion, this airway device is connected to a Mapleson breathing system. It delivers high-concentration oxygen at the laryngeal inlet, offering continuous positive airway pressure (CPAP) and delaying hypoxemia. The technique proves versatile across various patient profiles and procedures.
Wei Nasal Jet Tube: The Wei nasal jet tube introduces innovation with two additional channels for jet ventilation and gas sampling. In clinical trials, its use demonstrated a reduction in hypoxia during propofol-sedated upper GI endoscopies. While considered experimental, this technique may find application in advanced procedures, offering an alternative to traditional approaches.
Gastro-Laryngeal Tube (G-LT): Designed for deep sedation or general anesthesia during GI endoscopy, the G-LT provides a dedicated channel for endoscope insertion. Though effective in maintaining airway patency, complications like sore throat and mucosal erosion have been reported. Balancing its benefits with potential risks is crucial, particularly considering the necessity for general anesthesia.
LMA®GastroTM Airway: The LMA®GastroTM Airway introduces a dual-channel design for pulmonary ventilation and gastroscope insertion. Deep general anesthesia is required for its placement. Initial studies affirm its safety and effectiveness, emphasizing its role in low-risk patients undergoing diagnostic upper GI endoscopy.
Indications for Endotracheal Intubation in GI Endoscopy
1. Complex and Prolonged Procedures:
- Indication: Endotracheal intubation is recommended for complex and prolonged GI endoscopic procedures that may extend beyond the typical duration manageable under conscious sedation.
- Rationale: Ensures a secure airway throughout the extended duration of the procedure, minimizing the risk of respiratory compromise.
2. Patients with High Anesthetic Risk:
- Indication: Individuals with high anesthetic risk factors, such as severe cardiopulmonary diseases or compromised respiratory function.
- Rationale: Endotracheal intubation provides controlled ventilation and airway protection, mitigating the risks associated with pre-existing medical conditions.
3. Uncooperative or Agitated Patients:
- Indication: Patients who are uncooperative, agitated, or unable to tolerate the procedure under conscious sedation alone.
- Rationale: Ensures the safety of both the patient and the endoscopist by preventing sudden movements or complications related to inadequate sedation.
4. Emergency Situations:
- Indication: Emergent GI endoscopic procedures performed in response to life-threatening conditions, such as acute upper gastrointestinal bleeding.
- Rationale: Facilitates rapid intervention and resuscitation without the constraints of conscious sedation, ensuring immediate control of the airway.
5. Risk of Aspiration:
- Indication: Cases where there is a heightened risk of aspiration due to the nature of the procedure or the patient’s medical history.
- Rationale: Endotracheal intubation provides a definitive barrier against aspiration, safeguarding the patient from pulmonary complications.
6. Interventional Endoscopy:
- Indication: Procedures involving complex interventions, such as endoscopic retrograde cholangiopancreatography (ERCP) or endoscopic ultrasound (EUS).
- Rationale: Ensures optimal conditions for the endoscopist to perform intricate maneuvers while maintaining patient safety through secured airway management.