Via Aerea Dr Pablo Román Laringoscopia directa 2

Intubación Endotraqueal y Laringoscopia Directa

Introducción a la Intubación Endotraqueal

• La clase se centra en la intubación endotraqueal mediante laringoscopia directa, dividida en dos partes: definiciones, indicaciones y beneficios.

• Se abordará el equipamiento necesario, incluyendo el laringoscopio y los tubos endotraqueales.

Fases de la Laringoscopia Directa

• La laringoscopia directa permite exponer la anatomía de la laringe para facilitar el pasaje del tubo endotraqueal.

• Se discutirán las técnicas de intubación orotraqueal, destacando la laringoscopia directa como la más común.

Técnicas de Intubación Orotraqueal

• Existen varias técnicas para realizar intubación orotraqueal: laringoscopía directa, indirecta y con videoscopio.

• Otras formas incluyen el uso de fibrobroncoscopios y técnicas menos comunes como la intubación retrógrada.

Beneficios de la Intubación Orotraqueal

• Permite mantener una vía aérea permeable y facilita ventilaciones manuales y mecánicas a altas presiones.

• Protege contra broncoaspiraciones gracias al balón de neumotaponamiento del tubo endotraqueal.

Indicaciones para Intubación Orotraqueal

• Indicada en pacientes inconscientes o aquellos que requieren asistencia respiratoria mecánica prolongada.

• También se utiliza para proteger vías aéreas en pacientes conscientes con trastornos glóticos.

Herramientas Utilizadas: El Laringoscopio

• El laringoscopio es esencial para realizar laringoscopía directa; modelos iniciales fueron diseñados por Miller (1941) y Macintosh (1943).

• Los modelos actuales han evolucionado con diferentes características, incluyendo variaciones en iluminación y diseño.

Ventajas del Diseño Curvo del Laringoscopio

• La rama curva mejora la línea de visión al comprimir componentes del piso de la lengua durante el procedimiento.

• Modelos articulados permiten levantar estructuras obstructivas como la epiglotis durante el procedimiento.

Componentes Comunes del Laringoscopio

• Todos los laringoscopios comparten componentes básicos: cuchilla, sistema de encastre, mango, fuente de alimentación e iluminación.

Laryngoscopy Techniques and Equipment Overview

Selection of Laryngoscope Size

• The choice of laryngoscope size is crucial; typically, size three is used for female patients and size four for male patients to ensure proper fit.

• Selecting a laryngoscope that is too long can lead to excessive traction force, while one that is too short may not reach the epiglottic region effectively.

Importance of Laryngoscope Components

• It’s essential to check the functionality of the laryngoscope's locking mechanism, as malfunctioning equipment can complicate procedures in the operating room.

• The handle of the laryngoscope varies in length and diameter based on specific indications; it usually contains the power source for illumination.

Illumination Standards

• Proper lighting is critical; ISO standards recommend at least 500 lumens, with 2000 lumens being ideal for optimal visibility during procedures.

Endotracheal Tube Characteristics

• The classic endotracheal tube commonly used features a transparent PVC design with an inflatable cuff, which includes indicators like a balloon inflation gauge.

• Understanding components such as the Murphy eye (a side opening on the distal end) and its bevel angle are important for effective intubation.

Tube Sizing Considerations

• When selecting an endotracheal tube size, factors include internal diameter and intended use (oral vs. nasal), with pediatric applications often requiring different sizing rules.

• The goal in choosing tube size is to minimize trauma to mucosal surfaces while ensuring adequate suction capability and airflow resistance management.

Variants of Endotracheal Tubes

• Various types exist beyond standard tubes: non-cuffed tubes are often preferred in pediatrics due to smaller airway diameters; preformed tubes are utilized in head and neck surgeries.

• Spiralized tubes feature metal rings that prevent collapse during bending but require assistance for insertion due to their inability to maintain curvature.

Specialized Intubation Tools

• Specific tools like the Brain tube facilitate blind intubation through a mask, designed with silicone tips for minimal trauma during insertion.

Anesthesia Induction and Intubation Techniques

Overview of Equipment for Anesthesia Induction

• The importance of avoiding the engagement of the E-tube against the anterior wall of the trachea is highlighted. Special double-lumen tubes are used for pulmonary ventilation and separation during procedures.

• Laser surgery requires specific tubes designed to prevent damage from laser effects, along with tubes that have an inspiration system above the cuff, commonly used in prolonged intubations in intensive care.

Pre-Induction Checklist

• A basic equipment checklist is essential before performing endotracheal intubation during anesthesia induction. This ensures all necessary tools are prepared for a safe procedure.

• It is recommended to develop personal checklists to enhance safety and preparedness prior to anesthesia induction.

Direct Laryngoscopy Technique

Static Phase Preparation

• The direct laryngoscopy technique is divided into static and dynamic phases; static involves patient positioning, while dynamic focuses on mouth opening and tube passage.

• Proper camilla height is crucial for ergonomic intubation; it should align with the operator's sternal notch, while head positioning should be at epigastric level for optimal ventilation access.

Importance of Head Positioning

• Correct head alignment significantly impacts airway management; historical theories by Bister and Marbeck emphasize aligning oral, pharyngeal, and laryngeal axes through proper neck flexion using a cushion under the head (7-10 cm).

• Achieving "sniffing position" enhances alignment among these axes, facilitating better visualization during intubation procedures. Incorrect hyperextension can misalign these axes leading to poor visibility.

Anatomical Considerations in Airway Management

Curves in Airway Anatomy

• In 2008, Veiser introduced concepts regarding primary oropharyngeal and secondary laryngotracheal curves that affect airway management strategies during intubation procedures. Understanding these curves aids in optimizing line-of-sight during direct laryngoscopy.

• Greenland's study utilizing MRI demonstrated that both traditional three-axis theory and two-curved models converge on "sniffing position" as optimal for visualizing airways effectively during intubation maneuvers.

Implications of Patient Positioning

• Patient positioning directly influences airway curvature; improper flexion or extension can distort anatomical relationships critical for successful intubation outcomes by affecting visibility angles during procedures.

Dynamic Phase of Laryngoscopy

Overview of the Dynamic Phase

• The dynamic phase involves lateral displacement of the tongue and compression of submandibular tissues to elevate the epiglottis, enhancing visibility of the glottis. This is crucial for facilitating tube delivery into the trachea.

Techniques for Mouth Opening

• The mouth can be opened using a digital pinch maneuver, where the thumb presses on the lower dental arch and the index finger on the upper arch, allowing for easier introduction of laryngoscope blades.

• An alternative method involves extending the patient's head carefully to avoid cervical spine injury while using a pinky finger to pull down on the chin, which opens both mouth and tongue.

Identifying Structures During Laryngoscopy

• As you introduce the laryngoscope, expect to first see structures like the palatine pillars; rotating it 90 degrees towards sagittal plane helps in identifying critical areas such as epiglottis.

• Gentle traction should be applied towards antero-superior direction without excessive force to prevent damage to incisors or other structures during visualization.

Intubation Techniques and Classifications

Introduction to Intubation

• The session will cover endotracheal intubation techniques via laryngoscopy, including visual classifications that guide decision-making based on visibility during procedures. Discussions will also include verification methods for correct intubation and complications associated with direct laryngoscopy.

Cormack-Lehane Classification

• Cormack-Lehane's classification categorizes glottic view into four grades:

• Grade 1: Full view of glottic opening.

• Grade 2: Partial view including epiglottis.

• Grade 3: Only epiglottis visible.

• Grade 4: No identifiable structures; only base of tongue may be seen.

Modifications in Classification

• Modifications have been made over time:

• Grade 2 split into 2a (posterior glottic view) and 2b (no glottic view but some arytenoid visibility).

• Grade 3 divided into 3a (epiglottis separable from pharyngeal wall) and 3b (epiglottis not separable). Grade four remains unchanged as no visibility exists at this level.

Implications for Decision-Making

Impact on Clinical Decisions

• Tim Cook developed a three-level grading system based on ease of intubation:

• Easy: Grades I & IIa.

• Restricted: Grades IIb & IIIa.

• Difficult: Grades IIIb & IV.

External Mobilization Maneuver in Laryngoscopy

Overview of the Burp Maneuver

• The external mobilization maneuver, known as the "Burp" maneuver (Back Up Right Pressure), is recommended to be performed by the person conducting laryngoscopy, with assistance from another individual to maintain position.

Decision-Making Based on Cormack Classification

• Decisions during laryngoscopy can be guided by the Cormack classification; easy laryngoscopies allow for direct intubation with an endotracheal tube without significant difficulty.

• For Cormack grades 2b to 3a, using a facilitator such as a bougie or guide is advisable to navigate under the epiglottis and facilitate intubation.

Challenges in Difficult Laryngoscopies

• In difficult laryngoscopies, facilitators may not help if they lead towards the esophageal opening; thus, using a video laryngoscope becomes essential when visibility is compromised.

Optimization Strategies for Intubation

• Each line of life in intubation has common optimization strategies including manipulations, use of assistants or accessories, and adjustments in suction type/size and oxygen flow.

Specific Interventions for Improved Visibility

• Positioning patients correctly (flexion and sniffing position) enhances visibility during laryngoscopy. Changing tube size can also aid passage if initial attempts fail.

Identifying Problems During Direct Laryngoscopy

Types of Challenges Encountered

• Three main challenges arise during direct laryngoscopy:

• Inability to visualize structures (vision problem).

• Difficulty delivering the tube from mouth to glottic opening (delivery issue).

• Tube reaching the larynx but failing to pass through glottis/trachea (passage issue).

Targeted Optimizations Based on Issues

• Not all optimizations are necessary for every problem; specific maneuvers target vision issues while others focus on delivery or passage problems.

Importance of Relaxation Techniques

• If visualization is adequate but tube passage fails due to closed vocal cords, relaxation techniques may be more effective than switching tools like video scopes.

Defining Optimal Direct Laryngoscopy Attempts

Key Components of Successful Laryngoscopy

• An optimal attempt involves ensuring static conditions before dynamic actions: proper patient positioning, appropriate equipment selection, and performing necessary maneuvers like Burp if needed.

Contextual Considerations During Procedures

• The best approach depends on real-time context; practitioners must assess their actions continuously and declare their best effort after three attempts if intubation fails.

Verifying Endotracheal Intubation Success

Clinical Examination Methods

• Verification methods include clinical examination signs such as direct visualization of tube placement and observing respiratory movements. However, these are not definitive indicators of successful intubation.

Objective Confirmation Techniques

Airway Management and Intubation Techniques

Importance of Diagnostic Tools in Airway Management

• The flexible bronchoscopy is noted for its 100% diagnostic capability when used correctly, though it is not commonly employed as a diagnostic tool.

• To rule out esophageal intubation, ultrasound is utilized as the gold standard method. The phrase "no trace, no place" emphasizes that without a proper sonographic trace, the tube should be removed.

Guidelines for Preventing Esophageal Intubation

• A series of criteria have been established for sustained exhalation of carbon dioxide to diagnose orotracheal intubation. Understanding these criteria is crucial.

• An atypical capnography curve (not showing a plateau or descending) indicates possible esophageal intubation, necessitating immediate removal unless risky.

Complications Associated with Intubation

• Common complications during intubation include dental injuries from excessive traction and soft tissue damage due to tube placement or facilitators.

• Inadequate planning can lead to bronchial aspiration; rapid sequence intubation is essential in patients with full stomachs to avoid this risk.

Physiological Considerations During Laryngoscopy

• Laryngoscopy can cause cervical spine injury if not performed carefully; adequate sedation and relaxation are critical to prevent bronchospasm and hemodynamic changes.

• Poor anesthetic management during laryngoscopy may trigger hypertension and tachycardia, particularly concerning in critically ill patients undergoing cardiac surgery.

Strategies for Successful Intubation Attempts

• Unrecognized esophageal intubation leads to stomach overdistension and potential severe hypoxia if ventilation continues improperly.

• Each failed attempt at intubation reduces the likelihood of success on subsequent tries; thus, maximizing the first attempt's effectiveness is vital.

Best Practices for Laryngoscopy

• After each unsuccessful attempt, it's important to reassess ventilation strategies and consider modifications before retrying laryngoscopy.

• The recommended maximum number of laryngoscopies is three attempts plus one by the most experienced operator present.

Conclusion and Further Reading Recommendations

• The presentation covered Cormack-Lehane classification levels of view during laryngoscopy, challenges faced during orotracheal intubation, detection methods for esophageal intubations, and associated complications.