OBSTETRICAL PATIENTS POSE A CHALLENGE TO THE ANAESTHESIA PROVIDER. APART FROM VARIOUS PHYSIOLOGICAL CHANGES, AIRWAY CHANGES ALSO ARE OF IMPORTANT CONSIDERATION

1. AIRWAY MANAGEMENT IN
OBSTETRICS PATIENT
DR HASSAN

2. INTRODUCTION
The difficult airway is a clinical situation
which includes either difficulty with mask
ventilation or tracheal intubation or both.
Maintenance of the airway during obstetric
anaesthesia is difficult to estimate, still
remains the single most important cause of
anaesthesia related maternal morbidity and
mortality.

3. The key to any approach is to realize that all
external assessments are at least estimates as
to what will actually be visualized on direct
laryngoscopy of sedated and relaxed patient.
Difficult or failed intubations will occur, and
the only safe way to manage them is to be
well prepared.
Vigilance is the key, along with backup
plans and the availability of any necessary
equipment in case of difficulty.

4. What is the Incidence of Difficult
Intubation, Failed Intubation and
pulmonary aspiration in Obstetrics
patients?

5. Incidence of difficult endotracheal intubation
is approximately around 64/1000 parturient,
as compared to 45/1000 general population.
Failed Intubation occurs in approximately
0.13% to 0.35% or 1:750 to 1:280, of obstetric
patients versus 1:2,000 for all patients.
Incidence of Pulmonary aspiration of gastric
contents for obstetric patients is 1:500-400
versus 1:2,000 for all patients

6. What Are The Various Cardiovascular
Changes Occurring In Obstetrics
Patients Of Our Concern?

7.  Oxygen Consumption:-
 Increases 20-50%
50 % of this increase is required by uterus.
Despite the increase in Cardiac Output and
increase in alveolar ventilation oxygen,
consumption exceeds the requirements.

8. What Are The Various Respiratory
Changes Occurring In Obstetrics
Patients Of Our Concern?

9.  ↑ Respiratory Rate and ↑ Minute Ventilation
causes Excessive hyperventilation.
 This leads to marked hypocarbia and severe
alkalosis, which can lead to cerebral and
uteroplacental vasoconstriction.
 This may lead to both maternal & fetal hypoxia
Oxygen dissociation curve shifted toward right
Elevated level of 2,3DPG.

10. Diaphragm rises 4 cm which causes -
Less negative intrathoracic pressure
 FRC- (Functional Residual Capacity)
and RV(Residual Volume).
No impairments in diaphragmatic or
thoracic muscle motion
Lung compliance often poor( esp in
morbid obese patients)

11. Why Is There Increased Risk Of
Aspiration Pneumonitis In
Obstetrics Patients?

12. 1. GE junction:-Barrier Pressure-Decrease.
- Increase angle.
2. Cephalad displacement of stomach & pylorus.
3. PH < 2.5 - placental gastrin which increases
Hydrogen ion secretion of gastric acid.
4. Gastric volume > 25 ml ( 60%)
5. ↓ LES tone + ↑ intragastric Pressure +
↓ gastric emptying
6. Recent food intake prior to labour/ surgery

13. Why Is Airway Management
Difficult In Pregnant Females???

14. 1. Weight gain.(20kg or more by 3 Trimester)
2. Larger breasts, comes in the way of
laryngoscopy and Sellicks manoeuvre.
3. Upper airway edema and mucosal
congestion; mandates use of smaller
diameter CETT and extreme gentleness.

15. 4. Reduced FRC and increase rate of O2
consumption, makes it essential to keep the
laryngoscopy to less than 15sec to prevent
desaturation (during apnea ventilation)
5. Increased risk of regurgitation and
aspiration due to reduced LES and increased
intra-abdominal pressure.

16. 6. Inexperienced anesthetist (trainees) such as
in teaching institutes.
7. Increased used of regional anesthesia in
obstetric patients leading to decreased
practice.
8. The urgency of the operative procedure:
Dealing with obstetric patients is more of an
emergency situation rather than elective
process.

17. Why Is Bag Mask Ventilation
Difficult In Obstetrics Patient?

18. Bag mask ventilation is always more difficult
to perform in pregnant females because of the
weight of large breasts and the increase in the
intra abdominal pressure due to gravid uterus.
In case of difficult bag mask ventilation, help
of assistant and/or artificial airway should be
used.

19. PRE OP PREPARATION

20. Airway Assessment?

21. ‘LEMON’ for assessing difficulty during
laryngoscopy & intubation
(Look externally, examine 3-3-2,MMP,
obstruction, neck mobility)
Mouth opening.
 Thyro-mental distance.
 Atlanto-occipital joint extension.
A short neck, obesity, missing maxillary incisors
& a receding mandible are significant may cause
difficult failed intubation.

22. What Are The Alternative Airway
Equipments To Be Kept Ready
Before Intubation?

23. 2.Keeping alternative airway equipment cart
ready:
Apart from the essentials or regular
equipments such as McIntosh blades,
CETTs, stylets alternative equipments:-
1. Stubby handle laryngoscope/ polio blade
laryngoscope/ Mc coy blade. If these are
not available, detach the blade from
handle, then introduce the blade
separately and re-attach it to handle.

24. 2. Keep different sized CETT-6.5 ,7.0 mm ID.
3. LMA, Proseal LMA size 3, 4 & 5, ILMA.
4. Flexible fiber optic bronchoscopes, video
laryngoscopes.
5. Combitube.
6. Preparation for cricothyrotomy.
7. Preparation for transtracheal jet ventilation.

25. Anti Aspiration Prophylaxis
In Obstetric Patients?

26. 3.Consider aspiration prophylaxis:
Antacid prophylaxis
 Sodium citrate ( 30 ml of 0.3 M solution)
given 10-60 min before elective surgery, is
found to increase the pH of gastric contents
above 2.5.
H2- antagonist
 Ranitidine is affective at reducing gastric
pH & volume, especially when administered
with metoclopramide.
 i.v. ranitidine 50 mg is effective within 30
min of administration.

27. In the event of an extreme emergency, it
is still useful to give i.v. at induction
because it will be effective by the time the
mother emerges from anaesthesia.
Gastrokinetic agents such as
metoclopramide, a dopamine antagonist
may be used to accelerate gastric
emptying & increase LES tone.

28. Why Is Proper Positioning
Important In Such Patients?

29. 5.Careful Positioning of the parturient makes
the airway management a lot easier.
Shoulders should be elevated allowing the
enlarged breasts to fall away from neck and
chin while doughnut could be used to
support the occiput and place the head in
sniffing position.
6.Cricoid pressure should always be applied
while intubating assuming patient is full
stomach.

30. 30
-The normal supine
position often prevents
extension of the head and
makes endotracheal
intubation difficult.
-Elevation of the shoulder
allows some neck flexion
with more optimal
extension of the head at
the atlantooccipital joint,
facilitating intubation.

31. Anaesthetic Concern In Management
Of Difficult Airway In Obstetrics?

32. Management of Difficult Airway in Obstetrics
Along with difficult airway causes, pregnancy
related factors also increase the risk of
difficult airway.
Anesthesiologist should prefer a regional
technique when it is feasible.
Preferring regional technique does not mean
one will not face difficult airway (e.g., failure
of block, high level block, local anesthetic
toxicity, cardiac arrest).

33. Therefore, each pregnant woman must be
evaluated for difficult airway with history and
a combination of airway tests.
Despite airway evaluation, approximately
50% of unanticipated difficult airway cases
remain undetectable.
Anesthesiologist must have a plan for
anticipated and unanticipated difficult airway
scenarios.

34. Rapid sequence intubation is standard
during pregnancy due to the increased risk
of aspiration.
 Before induction, every pregnant patient
should receive 100% oxygen for at least 3-5
minutes for preoxygenation and
denitrogenation.
Manipulation of the airway should be
minimal to avoid bleeding and upper airway
trauma.

35. Awake fiber optic intubation is the first line
choice in patients with anticipated difficult
airway who are not candidates for regional
anesthesia.
fiber optic intubation is not an option in failed
intubation and poor laryngeal view when
anesthesia has already been induced.
Vigilance is the key along with back-up plan
and the availability of necessary equipment.

36. What Is The Difficult Airway
Society (DAS 2015) Algorithm
For Management Of Airway In
Obstetric Patient?

44. SUMMARY
Assume that every parturient has a
potentially difficult airway.
Evaluate the airway of every parturient;
have a back-up plan for every patient.
Have difficult airway equipment available.
Optimize patient’s position for intubation.
When faced with a difficult intubation, Call
for help.

45. When faced with a difficult intubation,
practitioners should choose the device they
are most experienced using. Do what you do
best!!!!
Don’t start surgery if oxygenation and
ventilation are unsatisfactory.
Choose regional anesthesia whenever
possible.

46. THANK YOU!