OSAS

Question 1

Define OSAS

Answer 1

Repititive episodes of hypopnea or apnea during sleep lasting for >10seconds resulting in >2% decrease in oxyhemoglobin caused by obstruction leading to collection of physiologic derangements

Question 2

What is apnea

Answer 2

Complete cessation of airflow in the airway

Question 3

What is hypopnea?

Answer 3

Cessation of airflow in the airway of >50%

Question 4

Wisconsin sleep cohort study

Answer 4

Age: 30-40
4% in men
3% in women

Question 5

Presenting symptoms of OSAS

Answer 5

Snoring
Gasping fo breath
Frequent wake up
Morning headache
Daytime sleepiness: Epworth sleepiness scale (0-24, normal 0-8)
Impaired concentration and memory

Question 6

Ix to reach Dx

Answer 6

Ess
Psg
Lat cephalogram
Ct scan - site and size of obstruction in ap and lateral
Sleep endoscopy - site

Question 7

What do u assess from lat ceph in OSAS?

Answer 7

Skeletal deformities
Airway
- soft palate length
- posterior airway space
- hyoid to mandibular plane distance (height of pharynx)

Question 8

What are infos PSG tells

Answer 8

Oxyhemoglobin saturation - hypoxemia, hypercapnia
Time of hypoxia
Marked swings in intrathoracic pressure
Sleep fragmentation

Question 9

Index to report obstuctive events

Answer 9

AHI : (apnea + hypopnea) / total sleeping time x60

RDI : AHI + RERA /hour

Question 10

PSG reading

Answer 10

For AHI
<5 is normal
5-15 is mild
15- 30 is moderate
>30 is severe 

For RDI
10-30 mild
30-50 moderate
>50 severe

Question 11

Fujita classification

Answer 11

Describes the anatomical position of airway obstruction

Type 1 - oropharyngeal obstruction (retropalatal)
Type 2 - oro and hypopharyngeal obstruction (retropalatal + retrolingual)
Type 3 - narrow hypopharyngeal (retrolingual)

Question 12

Tx Medical/ cons

Answer 12

weight loss 
diet control 
exercise
positioning during sleep
oral apliance 
cpap "gold standard"

Question 13

Phase 1: Soft tissue surgery (aka multilevel surgeries - surgeries at different sites of obstruction)

Answer 13

Uppp
Base of tongue reduction
Hyoid suspension

Question 14

Surgical tx - indication acc to AASM

Answer 14

Failure or rejection of cpap
Permanent cure desire
Specific dentofacial deformity
Medically fit

Question 15

Phase 2: Skeletal surgery

Answer 15

genioglossal advancement

mma

Question 16

Criteria for success

Answer 16

rdi <5/hr

Question 17

Complications of OSAS

Answer 17

Increased rates of DM, HPT, AF, Stroke, HF, Pulm HPT, CAD.
Difficult intubation
Likely to have perioperative airway obstruction, hypoxemia, atelactasis, ischemia, pneumonia, prolonged hospitalization