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General Surgery - NEETMDS- courses
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General Surgery

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

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.

Cricothyroidotomy

Cricothyroidotomy is a surgical procedure that involves making an incision through the skin over the cricothyroid membrane, which is located between the thyroid and cricoid cartilages in the neck. This procedure is performed to establish an emergency airway in situations where intubation is not possible or has failed, such as in cases of severe airway obstruction, facial trauma, or anaphylaxis.

Indications

Cricothyroidotomy is indicated in the following situations:

  • Acute Airway Obstruction: When there is a complete blockage of the upper airway due to swelling, foreign body, or trauma.
  • Failed Intubation: When attempts to secure an airway via endotracheal intubation have been unsuccessful.
  • Facial or Neck Trauma: In cases where traditional airway management is compromised due to injury.
  • Severe Anaphylaxis: When rapid airway access is needed and other methods are not feasible.

Anatomy

  • Cricothyroid Membrane: The membrane lies between the thyroid and cricoid cartilages and is a key landmark for the procedure.
  • Surrounding Structures: Important structures in the vicinity include the carotid arteries, jugular veins, and the recurrent laryngeal nerve, which must be avoided during the procedure.

Procedure

Preparation

  1. Positioning: The patient should be in a supine position with the neck extended to improve access to the cricothyroid membrane.
  2. Sterilization: The area should be cleaned and sterilized to reduce the risk of infection.
  3. Anesthesia: Local anesthesia may be administered, but in emergency situations, this step may be skipped.

Steps

  1. Identify the Cricothyroid Membrane: Palpate the thyroid and cricoid cartilages to locate the membrane, which is typically located about 1-2 cm below the thyroid notch.
  2. Make the Incision: Using a scalpel, make a vertical incision through the skin over the cricothyroid membrane, approximately 2-3 cm in length.
  3. Incise the Membrane: Carefully incise the cricothyroid membrane horizontally to create an opening into the airway.
  4. Insert the Airway Device:
    • A tracheostomy tube or a large-bore cannula (e.g., a 14-gauge catheter) is inserted into the opening to establish an airway.
    • Ensure that the device is positioned correctly to allow for ventilation.
  5. Secure the Airway: If using a tracheostomy tube, secure it in place to prevent dislodgment.

Post-Procedure Care

  • Ventilation: Connect the airway device to a bag-valve-mask (BVM) or ventilator to provide oxygenation and ventilation.
  • Monitoring: Continuously monitor the patient for signs of respiratory distress, oxygen saturation, and overall stability.
  • Consider Further Intervention: Plan for definitive airway management, such as a formal tracheostomy or endotracheal intubation, once the immediate crisis is resolved.

Complications

While cricothyroidotomy is a life-saving procedure, it can be associated with several complications, including:

  • Infection: Risk of infection at the incision site.
  • Hemorrhage: Potential bleeding from surrounding vessels.
  • Damage to Surrounding Structures: Injury to the recurrent laryngeal nerve, carotid arteries, or jugular veins.
  • Subcutaneous Emphysema: Air escaping into the subcutaneous tissue.
  • Tracheal Injury: If the incision is not made correctly, there is a risk of damaging the trachea.

Sinus

It is a tubular track lined by granulation tissue and open at one end which is at the surface,

eg. Tuberculous Sinus

Fistula

A tubular track lined by granulation tissue and open at both ends.at least one of which communicates with a hollow viscus. it can be internal or external.

Causes

1. Inadequate drainage

  • Abscess bursting at the non dependent part
  • Incision at the non-dependent part.
  • Narrow outer opening leading to collection of exudates in the cavity.

2. Presence of foreign body like sequestrum or slough.

3. Persistence of infection.

4. When the track is lined by epithelium

5. Specific causes, TB., Syphilis, etc.

6. Marked fibrosis of the wall with obliteration of blood vessels.

7. Poor general condition causing delayed healing.

Treatment

1. control of specific infection,

2. Thorough excision of track to open up the cavity. Removal of foreign body and scraping of the epithelium

3. Through Scrapping of the wall to expose healthy tissue

4. Wound laid open and allowed to heal from the bottom leaving no pocket,

Zygomatic Bone Reduction

When performing a reduction of the zygomatic bone, particularly in the context of maxillary arch fractures, several key checkpoints are used to assess the success of the procedure. Here’s a detailed overview of the important checkpoints for both zygomatic bone and zygomatic arch reduction.

Zygomatic Bone Reduction

  1. Alignment at the Sphenozygomatic Suture:

    • While this is considered the best checkpoint for assessing the reduction of the zygomatic bone, it may not always be the most practical or available option in certain clinical scenarios.
  2. Symmetry of the Zygomatic Arch:

    • Importance: This is the second-best checkpoint and serves multiple purposes:
      • Maintains Interzygomatic Distance: Ensures that the distance between the zygomatic bones is preserved, which is crucial for facial symmetry.
      • Maintains Facial Symmetry and Aesthetic Balance: A symmetrical zygomatic arch contributes to the overall aesthetic appearance of the face.
      • Preserves the Dome Effect: The prominence of the zygomatic arch creates a natural contour that is important for facial aesthetics.
  3. Continuity of the Infraorbital Rim:

    • A critical checkpoint indicating that the reduction is complete. The infraorbital rim should show no step-off, indicating proper alignment and continuity.
  4. Continuity at the Frontozygomatic Suture:

    • Ensures that the junction between the frontal bone and the zygomatic bone is intact and properly aligned.
  5. Continuity at the Zygomatic Buttress Region:

    • The zygomatic buttress is an important structural component that provides support and stability to the zygomatic bone.

Zygomatic Arch Reduction

  1. Click Sound:

    • The presence of a click sound during manipulation can indicate proper alignment and reduction of the zygomatic arch.
  2. Symmetry of the Arches:

    • Assessing the symmetry of the zygomatic arches on both sides of the face is crucial for ensuring that the reduction has been successful and that the facial aesthetics are preserved.

Inflammation is the respone of the body to an irritant.

Stages of Inflammation

1. General: Temperature Raised. In severe cases bacteremia or septicemia ,rigors may occur.

2. Local: classical signs of inflammation are due to hyperemia and inflammation exudate

i) Heat:  inflammed area feels warmer than the surrounding tissues.

ii) Redness

iii) Tenderness: Due to pressure of exudate on the surrounding nerves  If the exudate is  under tension, e.g. a furuncle (boil) of the ear, pain is severe.

iv) swelling

v) Loss of function.

The termination of Inflammation

This may be by:1. Resolution 2. Suppuration 3. Ulceration 4. Ganangren s. Fibrosis

Management

i. Increase the patients resistance., Rest,  Relief of pain by analgesics,  Diet: High protein and high calorie diet with vitamins,  Antibiotics,  Prevent further contamination of wound.

Surgical measures

1. Excision: If possible as in appendicectomy.

2. Incision and drainage: If an abscess forms.

Advanced Trauma Life Support (ATLS)

Introduction

Trauma is a leading cause of death, particularly in the first four decades of life, and ranks as the third most common cause of death overall. The Advanced Trauma Life Support (ATLS) program was developed to provide a systematic approach to the management of trauma patients, ensuring that life-threatening conditions are identified and treated promptly.

Mechanisms of Injury

In trauma, injuries can be classified based on their mechanisms:

Overt Mechanisms

  1. Penetrating Trauma: Injuries caused by objects that penetrate the skin and underlying tissues.
  2. Blunt Trauma: Injuries resulting from impact without penetration, such as collisions or falls.
  3. Thermal Trauma: Injuries caused by heat, including burns.
  4. Blast Injury: Injuries resulting from explosions, which can cause a combination of blunt and penetrating injuries.

Covert Mechanisms

  1. Blunt Trauma: Often results in internal injuries that may not be immediately apparent.
  2. Penetrating Trauma: Can include knife wounds and other sharp objects.
  3. Penetrating Knife: Specific injuries from stabbing.
  4. Gunshot Injury: Injuries caused by firearms, which can have extensive internal damage.

The track of penetrating injuries can often be identified by the anatomy involved, helping to determine which organs may be injured.

Steps in ATLS

The ATLS protocol consists of a systematic approach to trauma management, divided into two main surveys:

1. Primary Survey

  • Objective: Identify and treat life-threatening conditions.
  • Components:
    • A - Airway: Ensure the airway is patent. In patients with a Glasgow Coma Scale (GCS) of 8 or less, immediate intubation is necessary. Maintain cervical spine stability.
    • B - Breathing: Assess ventilation and oxygenation. Administer high-flow oxygen via a reservoir mask. Identify and treat conditions such as tension pneumothorax, flail chest, massive hemothorax, and open pneumothorax.
    • C - Circulation: Evaluate circulation based on:
      • Conscious level (indicates cerebral perfusion)
      • Skin color
      • Rapid, thready pulse (more reliable than blood pressure)
    • D - Disability: Assess neurological status using the Glasgow Coma Scale (GCS).
    • E - Exposure: Fully expose the patient to assess for injuries on the front and back.

2. Secondary Survey

  • Objective: Conduct a thorough head-to-toe examination to identify all injuries.
  • Components:
    • AMPLE: A mnemonic to gather important patient history:
      • A - Allergy: Any known allergies.
      • M - Medications: Current medications the patient is taking.
      • P - Past Medical History: Relevant medical history.
      • L - Last Meal: When the patient last ate.
      • E - Events of Incident: Details about the mechanism of injury.

Triage

Triage is the process of sorting patients based on the severity of their condition. The term "triage" comes from the French word meaning "to sort." In trauma settings, patients are categorized using a color-coded system:

  • Red: First priority (critical patients, e.g., tension pneumothorax).
  • Yellow: Second priority (urgent cases, e.g., pelvic fracture).
  • Green: Third priority (minor injuries, e.g., simple fracture).
  • Black: Zero priority (patients who are dead or unsalvageable).

Blunt Trauma

  • Common Causes: The most frequent cause of blunt trauma is road traffic accidents.
  • Seat Belt Use: Wearing seat belts significantly reduces mortality rates:
    • Front row occupants: 45% reduction in death rate.
    • Rear seat belt use: 80% reduction in death rate for front seat occupants.
  • Seat Belt Injuries: Marks on the thorax indicate a fourfold increase in thoracic injuries, while abdominal marks indicate a threefold increase in abdominal injuries.

Radiographs in Trauma

Key radiographic views to obtain in trauma cases include:

  1. Lateral cervical spine
  2. Anteroposterior chest
  3. Anteroposterior pelvis

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