1. SEVOFLURANE ANESTHESIA
WITHOUT MUSCLE RELAXANTS
FOR THORACOSCOPIC
THYMECTOMY
IN MYASTHENIA GRAVIS
Vo Van Hien
Nguyen Huu Tu
Mai Van Vien

2. Introduction
 Myasthenia gravis (MG) is a chronic autoimmune disorder
related to the thymus gland.
 Thymectomy is one of the effective methods to treat MG.
 Patients with myasthenia gravis did sentitivity to the drugs
were used in anesthesia → Choice drugs and anesthesia
technique plays an important role in the success of
operation.

3. introduction
 Respiratory complications depend on anesthetic technique:
 Mulder et al (1972): 50% of pts need ventilatory support.
 Suwanchi (1995): Comparision general anesthesia vs
epidural anesthesia and iv. propofol: early extubation in
operating room 29%- 78%.
 Catherine Chevalley et al (2001)(*):
+ Time need ventilation support : 2-48h
+ Propofol was used (1994): No need to ventilate
postoperative.

5. introduction
 In Vietnam, Đo Tat Cuong (1996) reported postoperative
ventilation depend on method of anesthesia :
 Anesthesia: 15.65%
 Acupunture: 3.5%
 Nguyen Van Thanh (1998) studied on 47 pts:
 Required ventilation support: 15/47pts
 Mortality: 3 patients due to respiratory infections.

6. introduction
Side effects of long-term ventilatory support on MG pts:
• Infections: respiratory, pneumonia, sepsis → death.
• Prolonged hospitalization days
• Increased treatment costs
Anesthesiologists’ recommendations:
“Avoid muscle relaxants in MG patients”

7. introduction
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8. objectives
To evaluate the use of sevoflurane and
without muscle relaxants
for thoracoscopic thymectomy in MG patients
and post-operative respiratory status

9. methods
 Subjects: Intervention study on 28 MG patients scheduled to
undergo thoracoscopic thymectomy
 Monitor: Datex Omeda: ECG (DII), SpO2, EtCO2, invasive
aterial blood pressure (ABP), module Entropy (RE, SE), TOF.
 Induction:
- Atropin: 0.5mg; Sufentanil: 0.5mcg/kg;
- Propofol 2.5-3 mg/kg
- Local anesthesia with 10 cc of lidocaine hydrochloride 2%
was sprayed on the vocal cords and into the trachea

10. methods
 Intubation Univent tube
- Loss eyelid reflex
- RE, SE<50
- Check tube and blocker’s position by endoscopy equipment
(Olympus)
 Ventilate A/C mode : Vt = 10ml/kg; f=14l/ph; FiO2= 60%→
PetCO2= 28-32 mmHg.
 OLV: Vt=5ml/kg, f=16-20; FiO2= 100% → Ppeak < 30 cm
H2O, PetCO2=30-35mmHg.
 Sufentanil: 0.2mcg/kg/h

11. methods
 Adjust concentration of sevoflurane
Criterial ABP > 130%
baseline
70% < ABP
<130%
ABP < 70%
baseline
RE, SE>60 ↑ Sevorane ↑ Sevorane
Increase infusion
and ephedrine iv
before ↑ Sevorane
40<RE,SE<60 Nicardipine iv
Adequate
depth of
anesthesia
Increase infusion
and ephedrine iv
RE, SE <40 Nicardipine iv ↓ Sevorane ↓ Sevorane

12. methods
 Stop sufentanil 15 minutes before the end of surgery
 Stop sevoflurane at the end of surgery.
 Extubation when:
- Awake
- Head lift > 5 seconds
- RR < 30/min
- Inspiratory force > 25cmH2O
 Assess respiratory status: breathing frequency; SpO2, blood
gas.
 Evaluate airway injuries at 24h postoperative.

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15. recorded Data
 General characteristics
 Intubation conditions (Viby Mogensen Score), number of
attemps to intubate.
 Hemodynamic changes at induction, before and after
intubation and intraoperative.
 Neuromuscular effect of sevoflurane on MG: TOF
 Surgeons’ satisfaction: VAS score
 Time to extubation and respiratory status: f, SpO2 , PaO2,
PaCO2, pH,…
 Clinical symtom due to airway injuries: sorethroat,
hoarseness and observe by laryngostroboscopy.

16. results
General characteristics
Characteristics Results
Gender
Male 8 (28.6%)
Female 20 (71.4%)
Age (X±SD) (years) 39.5 ± 9.7
Classification
(folow
Osserman)
I 5 (17.9%)
IIa 16 (57.1%)
IIb 7 (25.0%)
Duration of disease (months) 95.6 ± 8.73
3-121

17. Time in anesthesia
Time
Results
Loss eyelid reflex (seconds)
112.6± 28.5
57- 140
Achive RE, SE <50 (seconds)
149.5 ± 17.6
103 – 186
Intubation time (minutes)
6.0± 1.5
3.5 – 12.8
results

18. Agent dose for induction and maintaining
Purpose Results
Propofol for induction (mg) 189,75±40,3
110- 230
Total dose of sevoflurane for maintaining (ml) 125,35±59,6
Inspiratory concentration of sevorane for
maintaining (%)
3,05± 2,4
results

19. results
Intubation condition
82.1
17.9
0
100
80
60
40
20
0
Rate (%)
Excelent Good Poor
Intubation condition

20. results
Side effects intraoperative
Side Effects Results
Induction-
Intubation
Coughing 2 (10,5%)
Involuntary
3 (15,8%)
movements
Laryngospasm 0
Maintaining
Involuntary
movements
4 (21,1%)
Awake 0

21. 150
results
mmHg)
130
110
(IABP 90
Mean 70
50
T0 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 Induction
Intubation Surgery The
end
Mean IABP changes

22. results
Heart rate changes
150
130
110
90
70
50
T0 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14
Heart rate (f/min)

23. results
Neuromuscular transmission intraoperative
92.1
79.3* 75.3* 76.5*
91.7
100
80
60
40
20
0
TOF (%)
Baseline 30 min 60 min 90 min The end
Time

24. Dù kiÕn kÕt luËn

25. results
Relative between myasthenia class and TOF
at the 60th minute intraoperative
y = -10.6x + 97
R2 = 0.767; r= - 0.87579
100
90
(%)
80
TOF 70
60
50
Độ nhược cơ
(1:I; 2: IIa; 3:IIb) 1 2 3

26. results
Surgeons’ satisfaction
Level Results
Total satisfied 25 (89.3%)
Quite satisfied 3 (10.7%)
Medium 0
Poor 0
No satisfaction 0

27. Time in anesthesia
Duration Results
Duration of surgery (min)
125.6 ± 20.3
85 - 145
Duration of anessthesia (min)
143.7 ± 18.9
90 -180
Δ awake (min)
11.2± 2.9
8.0 – 15.0
extubation (min)
12.7 ± 3.7
8.0 -17.0
Self-awareness (min)
13.9 ± 1.9
8 -18
results
Δ awake (min) 11.2± 2.9
8.0- 15.0
Δ extubation(min) 12.7 ± 3.7
8.0- 17.0

28. spo2 and respiratory rate Changes after extubation
100
99
98
97
96
95
Before
15 min 30 min 2h 6h 12h 24h 48h 72h
extubation
24
RR (r/ph)
22
20
18
16
14
12
10
Before
15 min 30 min 2h 6h 12h 24h 48h 72h
extubation
SpO2 (%)

29. PaO2 changes
350
300
250
200
150
100
50
Pre-ope DLV OLV 2h after
extubation
1st day
post ope
2nd day
post-ope
3 rd day
post -ope
Arterial blood gas changes

30. PaCO2 changes
45
43
41
39
37
35
Pre-ope DLV OLV 2h after
extubation
1st day
post ope
2nd day
post ope
3rd post
ope
Arterial blood gas changes

31. pH changes
7.44
7.42
7.4
7.38
7.36
7.34
7.32
7.3
Pre-ope DLV OLV 2h after
extubation
1st day
post ope
2nd day
post ope
3rd post
ope
Arterial blood gas changes

32. Airway injuries
Clinical symtoms
Symtoms Results
Sore-throat 5 (17.8%)
Hoarseness 1(3.6%)
Both sore-throat and hoarseness 1(3.6%)
Total 7 (28.0%)
- ZHong and et al. 13%- 20%- 30%
- Heike K. 44% - 17%

33. Injuries were observed by laryngostroboscopy
No injury
78.5%
laryngeal injuries
14.3%
Both tracheal and
larygeal injuries
3.6%
Tracheal injuries
3.6%
Airway injuries

34. conclusions
Sevoflurane anesthesia without muscular relaxants for
thoracoscopic thymectomy in MG
Good intubating conditions
 Stable hemodynamic
Faster recovery
100% of the patients successfully to extubate at
operating room.
No patients required reintubation due to respiratory
failure.
Airway injuries due to intubation: 28%

35. Thank fo r your attention!