LARYNGOSCOPY

LARYNGOSCOPY


Introduction:

  • Laryngoscopy – Medical procedure for viewing vocal folds (vocal cords) & glottis.
  • Instrument used – Laryngoscope.
Important types of laryngoscope:

Macintosh type (MH-11): 

  • Most commonly used type.
  • Has curved blade.

Miller type:- 

  • Has straight blade

Fibreoptic laryngoscope:

  • Useful in difficult intubations.

Bullard laryngoscope: 

  • Contains fibreoptic channel visualizing laryngeal inlet directly.

McCoy laryngoscope:

  • Got a movable tip.

Magill type: 

  • Has straight blade.
  • Used for neonates.

Oxford infant blade:

  • Used for infants

Uses:

  • To facilitate tracheal intubation during GA or cardiopulmonary resuscitation.
  • Diagnostic or therapeutic procedures on larynx or other upper parts of tracheobronchial tree.

Types:

Direct laryngoscopy:

  • Direct visualization of larynx & hypopharynx

Indirect laryngoscopy:

  • An indirect visualization of larynx & hypopharynx.
  • Done by use of mirrors & light source at the back of the throat. (Image of larynx seen in mirror).

Microlaryngoscopy:

  • Laryngoscope is combined with operating microscope.
  • Started by Kleinsasser.
  • Provides excellent exposure of larynx to perform laryngeal microsurgeries (vocal cord cyst/nodule removal).
Technique for direct laryngoscopy:
  • Done in apnea with intermittent facemask inflation.
  • Inflation – Prevents hypoxemia & maintains inhalation anesthesia.

Precautions:

  • Usage of guard: Protects loose filled/capped teeth (especially upper incisors).

Components of direct laryngoscopy:

5 important components:

Optimal head & neck position:

  • Obtained by neck flexion, mivacurium & atlantooccipital joint extension.
  • Done by putting a small pillow under the occiput.

Optimal muscle relaxation:

  • Allows greatest exposure of larynx.
  • Prevents glottic closure. 

Drugs used: 

  • DOC – Succinylcholine for rapid (emergency) intubation.
  • Rocuronium, mivacurium & rapacuronium – Sch alternatives.

Optimal laryngoscope blade

  • Inserted from patient’s right side of mouth.
  • This prevents tongue blocking the larynx view.
  • Blade tip is advanced alongside tongue towards midline. 
  • In epiglottis, tip is inserted firmly but not forcibly into vallecula.
  • Hence, lifting epiglottis base forward to reveal cords. 
  • Curved laryngoscope blade preferred– Causes less stretching of faucial pillars than a straight blade.

Optimal external laryngeal manipulation:

  • Best maneuver – BURP (backward, upwards & to right pressure).
  • Backward & lateral pressure on larynx by anesthetist or assistant may help bring cords into view. 

Optimal use of introducer (bougie):

  • Gum elastic bougie (introducer) with coude tip – Single most useful aid for difficult direct laryngoscopy. 
  • Introduced into trachea & used as guide to railroad tracheal tube. 
  • Goal – To position endotracheal tube end @ 5 ± 2 cm proximal to trachea bifurcation i.e., carina.
  • Done with head & neck in neutral position. 
  • Neck flexion causes 2 cm ascent. 
  • Correct position of tip: 3 ± 2 cm from carina with flexed neck & 7 ± 2 cm from carina with extended neck.
Grading:
  • Cormack & Lehane grading:
  • Direct laryngoscopy grading for amount of larynx exposed.
Complications:
  • Occur due to interruption of protective reflexes.

CVS: 

  • Hypertension, tachycardia, cardiac arrhythmias, cardiac arrest, reflex bradycardia.
  • Treated by fentanyl, LA lignocaine spray, CCB (diltiazem).
  • CNS: Increases ICT, cerebral activity, blood flow & metabolic rate.
  • Eyes: Increases intraocular pressure (>40mm Hg)
  • Respiratory: Laryngospasm & bronchospasm.

Exam Important

  • Acute laryngeal spasm during indirect laryngoscopy is seen in Acute epiglottitis.
  • During laryngoscopy and endotracheal intubation, the laryngoscope is lifted upwards levering over the upper incisors maneuver is not performed.
  • Anesthesia used in microlaryngoscopy is Pollard tube with infiltration block.
  • In a direct laryngoscopy Cricothyroid, Lingual surface of epiglottis & Arytenoids can be visualized.
  • Hidden areas of larynx viz. infrahyoid epiglottis, anterior commissure, ventricles and subglottic region and apex of pyriform fossa are difficult to visualize by indirect laryngoscopy.
  • Microlaryngoscopy was started by Kleinsasser.
  • The procedure that should precede microlaryngoscopy is Rhinoscopy.
  • Laryngoscopy showing diagnosis of multiple juvenile papillomatosis of the larynx should be followed by Microlaryngoscopic surgery
  • Intraocular pressure rises in Intubation & laryngoscopy.
Don’t Forget to Solve all the previous Year Question asked on LARYNGOSCOPY
Click Here to Start Quiz

Module Below Start Quiz

Leave a Reply

%d bloggers like this:
Malcare WordPress Security