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

  1. 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.

  2. Obstruction of the Oral Cavity:

     • Conditions such as large tumors, severe swelling, or foreign bodies that obstruct the oral cavity can prevent successful intubation.

  3. Cervical Spine Instability:

     • Patients with unstable cervical spine injuries may be at risk of further injury if neck extension is required for intubation.

  4. Severe Maxillofacial Deformities:

     • Anatomical abnormalities that prevent proper visualization of the airway or access to the trachea.

  5. Inability to Open the Mouth:

     • Conditions such as trismus (lockjaw) or severe oral infections that limit mouth opening can hinder intubation.

  6. Severe Coagulopathy:

     • Patients with bleeding disorders may be at increased risk of bleeding during the procedure.

  7. Anticipated Difficult Airway:

     • In cases where the airway is expected to be difficult to manage, alternative methods may be preferred.

Contraindications for Tracheostomy

1. Severe Coagulopathy:

   • Patients with significant bleeding disorders may be at risk for excessive bleeding during the procedure.

2. 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.

3. Anatomical Abnormalities:

   • Significant anatomical variations or deformities in the neck that may complicate the procedure or increase the risk of injury to surrounding structures.

4. Severe Respiratory Distress:

   • In some cases, if a patient is in severe respiratory distress, immediate intubation may be prioritized over tracheostomy.

5. Patient Refusal:

   • If the patient is conscious and refuses the procedure, it should not be performed unless there is an immediate life-threatening situation.

6. 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.

7. Unstable Hemodynamics:

   • Patients with severe hemodynamic instability may not tolerate the procedure well, and alternative airway management strategies may be required.

SHOCK

Shock  is  defined  as  a  pathological  state  causing  inadequate  oxygen  delivery  to  the peripheral tissues and resulting in lactic acidosis, cellular hypoxia and disruption of normal metabolic condition.

CLASSIFICATION

Shock is generally classified into three major categories:

1.    Hypovolemic shock

2.    Cardiogenic shock

3.    Distributive shock

Distributive shock is further subdivided into three subgroups:

a.    Septic shock

b.    Neurogenic shock

c.    Anaphylactic shock

Hypovolemic  shock  is  present  when  marked  reduction  in  oxygen  delivery results from diminished cardiac output secondary to inadequate vascular volume. In general, it results from loss of fluid from circulation, either directly or indirectly.
e.g.    ?    Hemorrhage
    •    Loss of plasma due to burns
    •    Loss of water and electrolytes in diarrhea
    •    Third space loss (Internal fluid shift into inflammatory exudates in
        the peritoneum, such as in pancreatitis.)

Cardiogenic shock is present when there is severe reduction in oxygen delivery secondary to impaired cardiac function. Usually it is due to myocardial infarction or pericardial tamponade.

Septic Shock (vasogenic shock) develops as a result of the systemic effect of infection. It is the result of a septicemia with endotoxin and exotoxin release by gram-negative and gram-positive bacteria. Despite normal or increased cardiac output and oxygen delivery, cellular oxygen consumption is less than normal due to impaired extraction as a result of impaired metabolism.

Neurogenic shock results primarily from the disruption of the sympathetic nervous system which may be due to pain or loss of sympathetic tone, as in spinal cord injuries.

PATHO PHYSIOLOGY OF SHOCK

Shock stimulates a physiologic response. This circulatory response to hypotension is to conserve perfusion to the vital organs (heart and brain) at the expense of other tissues. Progressive vasoconstriction of skin, splanchnic and renal vessels leads to renal cortical necrosis and acute renal failure. If not corrected in time, shock leads to organ failure and sets up a vicious circle with hypoxia and acidosis.

CLINICAL FEATURES

The clinical presentation varies according to the cause. But in general patients with hypotension and reduced tissue perfusion presents with:
•    Tachycardia
•    Feeble pulse
•    Narrow pulse pressure
•    Cold extremities (except septic shock)
•    Sweating, anxiety
•    Breathlessness / Hyperventilation
•    Confusion leading to unconscious state

PATHO PHYSIOLOGY OF SHOCK

Shock stimulates a physiologic response. This circulatory response to hypotension is to conserve perfusion to the vital organs (heart and brain) at the expense of other tissues. Progressive vasoconstriction of skin, splanchnic and renal vessels leads to renal cortical necrosis and acute renal failure. If not corrected in time, shock leads to organ failure and sets up a vicious circle with hypoxia and acidosis.

CLINICAL FEATURES

The clinical presentation varies according to the cause. But in general patients with hypotension and reduced tissue perfusion presents with:
•    Tachycardia
•    Feeble pulse
•    Narrow pulse pressure
•    Cold extremities (except septic shock)
•    Sweating, anxiety
•    Breathlessness / Hyperventilation
•    Confusion leading to unconscious state

Dautrey Procedure

The Dautrey procedure is a surgical intervention aimed at preventing dislocation of the temporomandibular joint (TMJ) by creating a mechanical obstacle that restricts abnormal forward translation of the condylar head. This technique is particularly beneficial for patients who experience recurrent TMJ dislocations or subluxations, especially when conservative management strategies have proven ineffective.

1. Indications:

   • The Dautrey procedure is indicated for patients with a history of recurrent TMJ dislocations. It is particularly useful when conservative treatments, such as physical therapy or splint therapy, have failed to provide adequate stabilization of the joint.

2. Surgical Technique:

   • Osteotomy of the Zygomatic Arch: The procedure begins with an osteotomy, which involves surgically cutting the zygomatic arch, the bony structure that forms the prominence of the cheek.
   • Depressing the Zygomatic Arch: After the osteotomy, the zygomatic arch is depressed in front of the condylar head. This depression creates a physical barrier that acts as an obstacle to the forward movement of the condylar head during jaw opening or excessive movement.
   • Stabilization: The newly positioned zygomatic arch limits the range of motion of the condylar head, thereby reducing the risk of dislocation during functional activities such as chewing or speaking.

3. Mechanism of Action:

   • By altering the position of the zygomatic arch, the Dautrey procedure effectively changes the biomechanics of the TMJ. The new position of the zygomatic arch prevents the condylar head from translating too far forward, which is a common cause of dislocation.

4. Postoperative Care:

   • Following the procedure, patients may require a period of recovery and rehabilitation. This may include:
     • Dietary Modifications: Soft diet to minimize stress on the TMJ during the healing process.
     • Pain Management: Use of analgesics to manage postoperative discomfort.
     • Physical Therapy: Exercises to restore normal function and range of motion in the jaw.

5. Outcomes:

   • The Dautrey procedure has been shown to be effective in preventing recurrent TMJ dislocations. Patients often experience improved joint stability and a better quality of life following the surgery. Successful outcomes can lead to reduced pain, improved jaw function, and enhanced overall satisfaction with treatment.

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

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.

Suture Materials

Sutures are essential in surgical procedures for wound closure and tissue approximation. Various types of sutures are available, each with unique properties, advantages, and applications. Below is a summary of some commonly used suture materials, including chromic catgut, polypropylene, polyglycolic acid, and polyamide (nylon).

1. Chromic Catgut

• Description:

  • Chromic catgut is a natural absorbable suture made from collagen derived from the submucosa of sheep intestines or the serosa of beef cattle intestines. It is over 99% pure collagen.

• Absorption Process:

  • The absorption of chromic catgut occurs through enzymatic digestion by proteolytic enzymes, which are derived from lysozymes contained within polymorphonuclear leukocytes (polymorphs) and macrophages.

• Absorption Rate:

  • The absorption rate depends on the size of the suture and whether it is plain or chromicized. Typically, absorption is completed within 60-120 days.

• Applications:

  • Commonly used in soft tissue approximation and ligation, particularly in areas where a temporary support is needed.

2. Polypropylene (Proline)

• Description:

  • Polypropylene is a synthetic monofilament suture made from a purified and dyed polymer.

• Properties:

  • It has an extremely high tensile strength, which it retains indefinitely after implantation. Polypropylene is non-biodegradable, meaning it does not break down in the body.

• Applications:

  • Ideal for use in situations where long-term support is required, such as in vascular surgery, hernia repairs, and other procedures where permanent sutures are beneficial.

3. Polyglycolic Acid

• Description:

  • Polyglycolic acid is a synthetic absorbable suture formed by linking glycolic acid monomers to create a polymer.

• Properties:

  • It is known for its predictable absorption rate and is commonly used in various surgical applications.

• Applications:

  • Frequently used in soft tissue approximation, including in gastrointestinal and gynecological surgeries, where absorbable sutures are preferred.

4. Polyamide (Nylon)

• Description:

  • Polyamide, commonly known as nylon, is a synthetic non-absorbable suture that is chemically extruded and generally available in monofilament form.

• Properties:

  • Nylon sutures have a low coefficient of friction, making passage through tissue easy. They also elicit minimal tissue reaction.

• Applications:

  • Used in a variety of surgical procedures, including skin closure, where a strong, durable suture is required.

TMJ Ankylosis

Temporomandibular Joint (TMJ) ankylosis is a condition characterized by the abnormal fusion of the mandibular condyle to the temporal bone, leading to restricted jaw movement. This condition can significantly impact a patient's ability to open their mouth and perform normal functions such as eating and speaking.

Causes and Mechanisms of TMJ Ankylosis

1. Condylar Injuries:

   • Most cases of TMJ ankylosis result from condylar injuries sustained before the age of 10. The unique anatomy and physiology of the condyle in children contribute to the development of ankylosis.

2. Unique Pattern of Condylar Fractures in Children:

   • In children, the condylar cortical bone is thinner, and the condylar neck is broader. This anatomical configuration, combined with a rich subarticular vascular plexus, predisposes children to specific types of fractures.
   • Intracapsular Fractures: These fractures can lead to comminution (fragmentation) and hemarthrosis (bleeding into the joint) of the condylar head. A specific type of intracapsular fracture known as a "mushroom fracture" occurs, characterized by the comminution of the condylar head.

3. Formation of Fibrous Mass:

   • The presence of a highly osteogenic environment (one that promotes bone formation) following a fracture can lead to the organization of a fibrous mass. This mass can undergo ossification (the process of bone formation) and consolidation, ultimately resulting in ankylosis.

4. Trauma from Forceps Delivery:

   • TMJ ankylosis can also occur due to trauma sustained during forceps delivery, which may cause injury to the condylar region.

Etiology and Risk Factors

Laskin (1978) outlined several factors that may contribute to the etiology of TMJ ankylosis following trauma:

1. Age of Patient:

   • Younger patients have a significantly higher osteogenic potential and a more rapid healing response. The articular capsule in younger individuals is not as well developed, allowing for easier displacement of the condyle out of the fossa, which can damage the articular disk. Additionally, children may exhibit a greater tendency for prolonged self-imposed immobilization of the mandible after trauma.

2. Type of Fracture:

   • The condyle in children has a thinner cortex and a thicker neck, which predisposes them to a higher proportion of intracapsular comminuted fractures. In contrast, adults typically have a thinner condylar neck, which usually fractures at the neck, sparing the head of the condyle within the capsule.

3. Damage to the Articular Disk:

   • Direct contact between a comminuted condyle and the glenoid fossa, either due to a displaced or torn meniscus (articular disk), is a key factor in the development of ankylosis. This contact can lead to inflammation and subsequent bony fusion.

4. Period of Immobilization:

   • Prolonged mechanical immobilization or muscle splinting can promote orthogenesis (the formation of bone) and consolidation in an injured condyle. Total immobility between articular surfaces after a condylar injury can lead to a bony type of fusion, while some movement may result in a fibrous type of union.