nose ANATOMY OF AIRWAY : The airway commences at the and extends upto the terminal bronchioles.
NOSE ; It can be divided into external and internal nasal cavity.
EXTERNAL NOSE ; It has a bony part made of nasal bones nasal parts of frontal bones and frontal process of maxilla.It has also a series of cartilage in the lower part and a small zone of fibro-fatty tissue forming ala of the nose.
INTERNAL NOSE :The cavity of the nose is subdivided into two parts by the septum which opens exteriorly into nares and posteriorly into nasopharynx through choanae.
Each side of the nose presents a roof,a floor a medial and a lateral wall.
Roof :It slopes upward and backward to form the bridge of the nose (nasal and frontal bones), has a horizontal part (ciribriform part of ethmoid) and finally a downward slopping segment (the body of the ethmoid).
FLOOR : It is concave from side to side is formed by the palatine process of maxilla and the horizontal plate of palatine bone’
The medial wall :It comprises of the septum formed by septal cartilage .perpenicular plate of ethmoid and the vomer.
The lateral wall ;It has a bony framework made up of nasal aspect of ethmoidal labyrinth above, the nasal surface maxilla below and infront , and a perpendicular plate pf palatine bone behind it.It has three conchaes each arching over a meatus.
PHARYNX :It is a wide fibromuscular tube which joins the oral and nasal cavity in front to the larynx below it. It extends from the basilar part of the skull to the origin of the oesophagus at the level of C6 vertrebra .It is divided into nasopharynx, oropharynx and laryngopharynx
Nasopharynx : It lies behind the nasal cavity above soft palate.It communicates with the oropharynx through pharyngeal isthmus which is closed during deglutition by lifting soft palate.The nasopharyngeal tonsil is primary cause of obstruction in this region.
Oropharynx :The mouth cavity leads to oropharynx through the oropharyngeal isthmus which is bound by the soft palate,palatoglossus arches and the dorsum of the tongue.
Laryngopharynx It extends from from the tip of the level of C6.Structurally the larynx consists of framework of articulating cartilages linked together by ligaments which moves in relation to each other by the action of laryngeal muscles .
Laryngeal cartilages :thyroid, cricoid , paired arytenoids with epiglottis ,corniculate and cuneiform cartilages.
Trachea It extetends from the lower border of cricoid cartilage to its termination at the bronchial bifurcation. It is about 15 cm long in adult and diameter corresponds to that of patient index finger’.
Ask the patient about the problems prior to anesthesia such as jaw pain, hoarseness of voice ,dental injury etc._that may suggest difficult intubation.
If the patient was informed by the anesthtetist that he was difficult to ventilate or intubate.
The condition ,the pt had earlier might have worsened.
History suggestive of following disorder: diabetes, obstructive sleep apnoea , obesity. rheumatoid arthritis, zenker diverticulum,acromegaly,pregnancy,anaphylaxis,mediastinal masses,xepiglottis,the airway in HIV patient,Ludwig,s angina,retropharyngeal abscess.
GENERAL, PHYSICAL AND REGIONAL A global assessment should include the following:
Age , height, bodyweight, mouth opening, teeth, palate, ability to protrude the lower jaw, measurement of sub mental space, patient neck ,general body habitus,infection of airway, systemic diseases etc.
Anaesthesia face mask are rubber or plastic employed to administer oxygen or to ventilate the nonintibuted patient.
The mask should be hold with index and thumb and other three fingers to pull the mandible upward.
Mandibular displacement along the cervical extension and chin lift, all tend to pull the tongue and soft tissue up of posterior pharyngeal wall and relieve the obstruction of airway in anesthetized patient.
Some time, it may be required to hold the mask with two hands and vigorously pulling the mandible upward .
When airway integrity can be maintained with manipulation of mask, mandible or neck a airway of appropriate size can restore the patency .Air way are two types – oral and nasal.
Appropriate size of airway corresponds to distance between angle of mouth to angle of mandible. The airway may be inserted right side up or up side down than rotated 180 degree into the position of function.
Nasal airways are useful in patient who are not deeply anesthetized because such airway tends to provoke less airway stimulation.
It is double lumen tube that is inserted blindly. The esophageal lumen has a closed distal end. while inserting , the tongue and mandible are lifted with one hand and introduce the tube in the direction of normal curvature of pharynx with the another hand
Pharyngeal cuff is inflated with 100ml of air and distal end with 15ml.Ventilation is started with the longer tube because placement is usually esophagus. If there is no signs of lung ventilation and stomach being inflated ,ventilation should be started with second tube.
It is performed by by placing a 12-14 gauge needle or catheter through cricothyrroid membrane into the trchea. An alternative site is the subcricoid region beween the cricoid cartilage and the first tracheal ring.The needle is fixed with an artery forcep.Intermittent pressurized oxygen provides the most suitable method for ventilation through this small needle and simplest method is to use emergency oxygen flush.