Prof. Minnu Panditrao describes the details of history, developement, conduct and recent advances of Total Intra venous Anaesthesia (TIVA)

1. TIVA IN 21ST CENTURY
Dr. Mrs. Minnu M. Panditrao
Consultant
Dept. Anesthesiology & ICU
Rand memeorial Hospital
Freeport, Bahamas

2. DEFINITION:
It is a form of balanced anaesthesia where the
anaesthetic state is achieved with the help of
intravenous administration of a combination of
hypnotic & analgesic drugs without the use of
inhalational anaesthetic agents including N2O

3. HISTORY:
 Christopher Wren 1657
 Alexander Wood 1853
 Pierre Cyprien Ore 1874 (Chloral Hydrate)
 Drs. Waters & Lundy 1934 (Thiopentane)
 Dr. Stoelting 1957 (Methiohexital)

4. HISTORY:
 Ketamine 1959
 Propanidid, Althesin, Etomidate,
 Diazepam (In 1960-80)
 Propofol & Newer Opioids 1980s

5. INTRODUCTION:
Volatile Inhalational Agents & N2O avoided
PROBLEMS: IN THE PAST
- Unavailability of satisfactory drugs
- Inadequate methods of administration
Nowadays these problems have been solved.

6. BENEFITS OF TIVA:
1. Rapid & Smooth Induction
2. Better Control of Depth
3. Decreased Awareness
4. Fast Recovery
5. Reduced Nausea Vomiting
6. Reduced Stress Response
7. No Organ Toxicity
8. N2O Side Effects Avoided

7. BENEFITS (contd.):
9. Better for Neurosurgery
10. Higher conc. of O2 possible
11. Better for Airway Endoscopies
12. For Transits of Remote Locations Better
13. During CPB (Cardiac Surgery)
14. No atmospheric pollution, No
environmental damage
15. For prevention of MH in susceptible cases

8. DISADVANTAGES OF TIVA
1. Once IV drug given, can’t be retrieved
2. Phlebitis, Venous Irritation
3. High Cost
4. Infection in Propofol
5. Special Equipment is required

9. Can Be Administered By:
1. Intermittent Boluses
2. Continuous Infusion

13. Advantages of Infusion
1. Oscillations in Drug conc. Avoided
2. Overdosing & Underdosing Avoided
3. Provides stable depth of anaesthesia
4. Side Effects reduced
5. Recovery time reduced
6. Total Drug requirements decreased
(by 25-30%)

14. Disadvantages:
1. More Expensive & Complicated Equipment
2. Difficult to Use

15. RECENT ADVANCES:
TCIS (Target Controlled Infusion Systems)
- Diprifusor
TIVA with Closed Loop Control of
Anaesthesia with
- AEPI
- BIS
CLAN (Closed Loop Anaesthesia)

16. INDUCTION OF TIVA:
Factors Influencing the Dose:
KeO--Rate constant, is proportional to onset
of action
Concentration Gradient between the blood &
the effect site, is inversely proportional to
onset of action

17. CLINICAL SIGNIFICANCE
Propofol & Thiopentone because of their large
KeO are better for induction
Induction doses vary depending upon
pharmacokinetic & pharmacodynamic factors
Addition of 2 inhalational agents is simply
additive but of IV agents is synergistic
Synergism helps it providing adequate depth
for stronger stimuli

18. CLINICAL SIGNIFICANCE (contd.)
Decreased dose requirement provides more
haemodynamic stability
However synergism for side-effects
(respiratory depression) should be kept in
mind

19. INDUCTION WITH
INDIVIDUAL/COMBINATION OF DRUGS
1. Propofol:
Induction dose is 1-2.5 mg/kg.
Blood conc. reqd. is 2.5-5.5 μg/ml
Onset of action is <60 sec.
Time to peak effect is 90 sec.
Duration of hypnosis is 5-10 min.
Premedication with Opioids reduces the
Induction Dose

20. 2. Propofol with Opioids:
Effect is Synergistic
Reduced dosage required
3. Ketamine:
As a supplement to Propofol– Effect is
additive
Ketamine+Benzodiazepines+Opioids have
also been used

21. MAINTENANCE WITH TIVA
Factors controlling the dosage:
Intensity of Surgical stimulation
Clinical signs of depth of anaesthesia

22. CLINICAL SIGNIFICANCE
Adjust the dose depending upon the
response to Surgical stimulus
Higher dose required during Laryngoscopy
& Intubation
Lower dose requirement during scrubbing,
prep & draping
Requirement of max. conc.(2xCP50) at the
time of skin incision

23. CLINICAL SIGNIFICANCE (contd.)
Patients movement, haemodynamics &/or
autonomic responses indicate inadequate
anaesthesia
Other indicators like BIS, AEPI, Train of 4
have been tried with variable success
If no response for 10-15 min., decrease
infusion rate by 20%
Once patient starts responding, administer a
bolus & set the new infusion rate midway
between previous & present new rate

24. CLINICAL SIGNIFICANCE (contd.)
Potent Opioid should be given for adequate
analgesia
Continuous titration of hypnotic must be
done & concept of CSHT kept in mind
Net requirement of dose depends not only
upon pharmacokinetics but also on
pharmacodynamic variables

25. MAINTENANCE WITH
INDIVIDUAL/COMBINATION OF DRUGS
1. Propofol:
Should be used along with an analgesic
A manual infusion scheme is
Loading dose 1-2mg/kg, followed by
10 mg/kg-hr for 10 min., followed by
8 mg/kg-hr for next 10 min. &
6 mg/kg-hr thereafter
This provides a blood Propofol conc. of
3.7 μg/ml within 2 min.

26. Propofol
Induction of GA: 1-1.2 mg/kg IV, dose
decreased in patients >50yrs
Maintenance of GA: 80-150 Μg/kg-min. IV
with Opioids, dose decreased in patients >50
yrs
Sedation: 10-50 μg/kg-min. IV infusion

27. Other agents used are Opioids, Benzodiazepines &
Ketamine
Only Ketamine can be used as a sole agent
Its disadvantages being long recovery time &
emergence phenomena
Recommended Ketamine infusion regimen is:
0.5-1 mg/kg IV, as required, with 50% N2O in O2
10-15 μg/kg-min., with 50% N2O in O2
30-90 Μg/kg-min., without N2O

28. Recommended Opioid infusion regimen for
maintenance of anaesthesia along with a
hypnotic are
Drug Target plasma Bolus Infusion
Conc. (ng/ml) μg/kg rate
μg/kg/min
Fentanyl 1 3 0.020
Alfentanil 40 20 0.2
Sufentanil 0.5 0.5 0.01
Remifentanil 3 1 0.1

29. RECOVERY FROM TIVA
Recovery is due to redistribution & not due to
elimination
Decline in plasma conc. is due to distribution
from central to peripheral comp. & elimination
Distribution & elimination depends upon eqbm.
between central & peripheral comp.

30. CONTEXT SENSITIVE HALF TIME (CSHT)
It is the time taken for plasma conc. to
decline by 50% after infusion of different
duration designed to maintain a constant
plasma conc.
This concept takes into consideration
- Elimination &
- Distribution
CSHT increases with the increase in duration
of infusion

31. CLINICAL SIGNIFICANCE
Drugs that are metabolised & eliminated rapidly
have short CSHT which is not affected by
longer periods of infusion
Recovery time for a drug varies depending
upon its duration of infusion & desired %age
decline required for recovery
Time to recovery depends upon the difference
between the maintenance conc. & threshold
conc. (%age decline) required for recovery.
This %age decline may vary from 20%(with
Opioid+Hypnotic) to 80%(when only hypnotic is
used

32. RECOVERY CHARACTERISTICS OF
INDIVIDUAL AGENTS
1. Propofol:
- Avg. Propofol blood conc. for:
awakening is 1.6 μg/ml
orientation is 1.2 μg/ml
- CHST for Propofol
after 3 hrs is 25 min.
after 8 hrs is 40 min.
The required %age decrease in Propofol conc.
for awakening is <50% so recovery will remain
rapid even after prolonged infusions.
When combined with Opioids recovery time is
even shorter(9-12 min. with Fentanyl)

33. 2. Opioids:
CSHT for Fentanyl, Sufentanil &
Alfentanil are:
after 1 hr infusion-20% ↓ in 15-20 min.
after 4 hr infusion-20% ↓ for Sufent &
Alfent takes half as long as for Fentanyl
after 10 hrs infusion-20% ↓ for Fentanyl
is 45 min & for Sufent & Alfent is ¼ of
that
With Remifentanil as it has shortest
CSHT, most patients recover within 3-5
min. after stopping its infusion

34. SUMMARY
TIVA in 21st Century has come a long way
Propofol (1986)
First syringe driver by Ohmeda
Diprifusor chip software
TCI & CLAN