NEET MDS Lessons
General Surgery
Intubation
Intubation is a critical procedure in airway management, and the choice of technique—oral intubation, nasal intubation, or tracheostomy—depends on the clinical situation, patient anatomy, and specific indications or contraindications.
Indications for Each Intubation Technique
1. Oral Intubation
Oral intubation is often the preferred method in emergency situations and when nasal intubation is contraindicated. Indications include:
- Emergent Intubation: Situations such as cardiopulmonary resuscitation (CPR), unconsciousness, or apnea.
- Oral or Mandibular Trauma: When there is significant trauma to the oral cavity or mandible that may complicate nasal access.
- Cervical Spine Conditions: Conditions such as ankylosis, arthritis, or trauma that may limit neck movement.
- Gagging and Vomiting: In patients who are unable to protect their airway due to these conditions.
- Agitation: In cases where the patient is agitated and requires sedation and airway protection.
2. Nasal Intubation
Nasal intubation is indicated in specific situations where oral intubation may be difficult or impossible. Indications include:
- Nasal Obstruction: When there is a blockage in the oral route.
- Paranasal Disease: Conditions affecting the nasal passages that may necessitate nasal access.
- Awake Intubation: In cases where the patient is cooperative and can tolerate the procedure.
- Short (Bull) Neck: In patients with anatomical challenges that make oral intubation difficult.
3. Tracheostomy
Tracheostomy is indicated for long-term airway management or when other methods are not feasible. Indications include:
- Inability to Insert Translational Tube: When oral or nasal intubation fails or is not possible.
- Need for Long-Term Definitive Airway: In patients requiring prolonged mechanical ventilation or airway support.
- Obstruction Above Cricoid Cartilage: Conditions that obstruct the airway at or above the cricoid level.
- Complications of Translational Intubation: Such as glottic incompetence or inability to clear tracheobronchial secretions.
- Sleep Apnea Unresponsive to CPAP: In patients with severe obstructive sleep apnea who do not respond to continuous positive airway pressure (CPAP) therapy.
- Facial or Laryngeal Trauma: Structural contraindications to translaryngeal intubation.
Contraindications for Nasal Intubation
- Severe Fractures of the Midface: Nasal intubation is contraindicated due to the risk of further injury and complications.
- Nasal Fractures: Similar to midface fractures, nasal fractures can complicate nasal intubation and increase the risk of injury.
- Basilar Skull Fractures: The risk of entering the cranial cavity or causing cerebrospinal fluid (CSF) leaks makes nasal intubation unsafe in these cases.
-
Contraindications for Oral Intubation
-
Severe Facial or Oral Trauma:
- Significant injuries to the face, jaw, or oral cavity may make oral intubation difficult or impossible and increase the risk of further injury.
-
Obstruction of the Oral Cavity:
- Conditions such as large tumors, severe swelling, or foreign bodies that obstruct the oral cavity can prevent successful intubation.
-
Cervical Spine Instability:
- Patients with unstable cervical spine injuries may be at risk of further injury if neck extension is required for intubation.
-
Severe Maxillofacial Deformities:
- Anatomical abnormalities that prevent proper visualization of the airway or access to the trachea.
-
Inability to Open the Mouth:
- Conditions such as trismus (lockjaw) or severe oral infections that limit mouth opening can hinder intubation.
-
Severe Coagulopathy:
- Patients with bleeding disorders may be at increased risk of bleeding during the procedure.
-
Anticipated Difficult Airway:
- In cases where the airway is expected to be difficult to manage, alternative methods may be preferred.
-
Contraindications for Tracheostomy
-
Severe Coagulopathy:
- Patients with significant bleeding disorders may be at risk for excessive bleeding during the procedure.
-
Infection at the Site of Incision:
- Active infections in the neck or tracheostomy site can increase the risk of complications and should be addressed before proceeding.
-
Anatomical Abnormalities:
- Significant anatomical variations or deformities in the neck that may complicate the procedure or increase the risk of injury to surrounding structures.
-
Severe Respiratory Distress:
- In some cases, if a patient is in severe respiratory distress, immediate intubation may be prioritized over tracheostomy.
-
Patient Refusal:
- If the patient is conscious and refuses the procedure, it should not be performed unless there is an immediate life-threatening situation.
-
Inability to Maintain Ventilation:
- If the patient cannot be adequately ventilated through other means, tracheostomy may be necessary, but it should be performed with caution.
-
Unstable Hemodynamics:
- Patients with severe hemodynamic instability may not tolerate the procedure well, and alternative airway management strategies may be required.
Tracheostomy
Tracheostomy is a surgical procedure that involves creating an opening in the trachea (windpipe) to facilitate breathing. This procedure is typically performed when there is a need for prolonged airway access, especially in cases where the upper airway is obstructed or compromised. The incision is usually made between the 2nd and 4th tracheal rings, as entry through the 1st ring can lead to complications such as tracheal stenosis.
Indications
Tracheostomy may be indicated in various clinical scenarios, including:
- Acute Upper Airway Obstruction: Conditions such as severe allergic reactions, infections (e.g., epiglottitis), or trauma that obstruct the airway.
- Major Surgery: Procedures involving the mouth, pharynx, or larynx that may compromise the airway.
- Prolonged Mechanical Ventilation: Patients requiring artificial ventilation for an extended period, such as those with respiratory failure.
- Unconscious Patients: Situations involving head injuries, tetanus, or bulbar poliomyelitis where airway protection is necessary.
Procedure
Technique
- Incision: A horizontal incision is made in the skin over the trachea, typically between the 2nd and 4th tracheal rings.
- Dissection: The subcutaneous tissue and muscles are dissected to expose the trachea.
- Tracheal Entry: An incision is made in the trachea, and a tracheostomy tube is inserted to maintain the airway.
Complications of Tracheostomy
Tracheostomy can be associated with several complications, which can be categorized into intraoperative, early postoperative, and late postoperative complications.
1. Intraoperative Complications
- Hemorrhage: Bleeding can occur during the procedure, particularly if major blood vessels are inadvertently injured.
- Injury to Paratracheal Structures:
- Carotid Artery: Injury can lead to significant hemorrhage and potential airway compromise.
- Recurrent Laryngeal Nerve: Damage can result in vocal cord paralysis and hoarseness.
- Esophagus: Injury can lead to tracheoesophageal fistula formation.
- Trachea: Improper technique can cause tracheal injury.
2. Early Postoperative Complications
- Apnea: Temporary cessation of breathing may occur, especially in patients with pre-existing respiratory issues.
- Hemorrhage: Postoperative bleeding can occur, requiring surgical intervention.
- Subcutaneous Emphysema: Air can escape into the subcutaneous tissue, leading to swelling and discomfort.
- Pneumomediastinum and Pneumothorax: Air can enter the mediastinum or pleural space, leading to respiratory distress.
- Infection: Risk of infection at the incision site or within the tracheostomy tube.
3. Late Postoperative Complications
- Difficult Decannulation: Challenges in removing the tracheostomy tube due to airway swelling or other factors.
- Tracheocutaneous Fistula: An abnormal connection between the trachea and the skin, which may require surgical repair.
- Tracheoesophageal Fistula: An abnormal connection between the trachea and esophagus, leading to aspiration and feeding difficulties.
- Tracheoinnominate Arterial Fistula: A rare but life-threatening complication where the trachea erodes into the innominate artery, resulting in severe hemorrhage.
- Tracheal Stenosis: Narrowing of the trachea due to scar tissue formation, which can lead to breathing difficulties.
Ludwig's Angina
Ludwig's angina is a serious, potentially life-threatening cellulitis or connective tissue infection of the submandibular space. It typically arises from infections of the teeth, particularly the second or third molars, and can lead to airway obstruction due to swelling. This condition is named after the German physician Wilhelm Friedrich von Ludwig, who first described it in the 19th century.
Etiology
-
Common Causes:
- Dental infections (especially from the lower molars)
- Infections from the floor of the mouth
- Trauma to the submandibular area
- Occasionally, infections can arise from other sources, such as the oropharynx or skin.
-
Microbial Agents:
- Mixed flora, including both aerobic and anaerobic bacteria.
- Common organisms include Streptococcus, Staphylococcus, and Bacteroides species.
Pathophysiology
- The infection typically begins in the submandibular space and can spread rapidly due to the loose connective tissue in this area.
- The swelling can lead to displacement of the tongue and can obstruct the airway, making it a medical emergency.
Clinical Presentation
-
Symptoms:
- Swelling of the submandibular area, which may be bilateral
- "Brawny induration" (firm, non-fluctuant swelling)
- Pain and tenderness in the submandibular region
- Difficulty swallowing (dysphagia) and speaking (dysarthria)
- Fever and malaise
- Possible elevation of the floor of the mouth and displacement of the tongue
-
Signs:
- Swelling may extend to the neck and may cause "bull neck" appearance.
- Trismus (limited mouth opening) may be present.
- Respiratory distress due to airway compromise.
Diagnosis
- Clinical Evaluation: Diagnosis is primarily clinical based on history and physical examination.
- Imaging:
- CT scan of the neck may be used to assess the extent of the infection and to rule out other conditions.
- X-rays may show air in the soft tissues if there is a necrotizing infection.
Management
Initial Management
- Airway Management:
- Ensure the airway is patent; this may require intubation or tracheostomy in severe cases.
Medical Treatment
- Antibiotics:
- Broad-spectrum intravenous antibiotics are initiated to cover both
aerobic and anaerobic bacteria. Common regimens may include:
- Ampicillin-sulbactam
- Clindamycin
- Metronidazole combined with a penicillin derivative
- Broad-spectrum intravenous antibiotics are initiated to cover both
aerobic and anaerobic bacteria. Common regimens may include:
Surgical Intervention
- Drainage:
- Surgical drainage may be necessary if there is an abscess formation or significant swelling.
- Incisions are typically made in the submandibular area to allow for drainage of pus and to relieve pressure.
Complications
- Airway Obstruction: The most critical complication, requiring immediate intervention.
- Sepsis: Can occur if the infection spreads systemically.
- Necrotizing fasciitis: Rare but serious complication that may require extensive surgical intervention.
- Thrombosis of the internal jugular vein: Can occur due to the spread of infection.
Prognosis
- With prompt diagnosis and treatment, the prognosis is generally good. However, delays in management can lead to significant morbidity and mortality due to airway compromise and systemic infection.