EFFECTS OF TOURNIQUET AND ITS EFFECTS ON PATIENTS PHYSIOLOGY

1. Presentor : Dr.Kumar
Moderator : Dr.vamsidhar
TOURNIQUET IN
ANAESTHESIA

2. History
 Jean Louis Petit coined the word
“Tourniquet” from theFrench word
tourner (to turn) in 1718 when he
used them for lower limb
amputations to reduce blood loss.
 In 1873 , Johan friedrich august
von esmarch introduced flat
rubber tube wrapped repeatedly
around the limb as tourniquet
 In 1904 Harvey cushing
introduced pneumatic tourniquet to
limb surgery
Johan friedrich august von
esmarch

3.  pneumatic tourniquets consist of three
basiccomponents:
1. a cuff, similar to a blood pressure
cuff,which is wrapped around a
patient's limb and then inflated
2. a compressed gas source
3. pressure gauge, designed to
maintain pressure in the cuff at a set
value.
 Automatic tourniquets allow the
intended pressure to be preset before
inflation and have controllers that

4.  Arterial tourniquets are used for
1. extremity surgery to reduce blood loss and provide
good operating conditions,
2. for intravenous regional anaesthesia,( Biers block )
3. for intravenous regional sympathectomy in the
management of complex regional pain syndromes
and
4. for isolated limb perfusion in the management of
localised malignancy

5. Tourniquet pressure
Tourniquet pressure :
 50 – 100 mm of Hg above the systolic blood
pressure.
 Upper limb 250 mm of Hg
 Lower limb 350 mm of hg
Doppler occlusion pressure (DOP) :
 Upper limb DOP + 50 mm of Hg
 Lower limb DOP + 75 mm of Hg Above the
DOPR.
 Upper limb 135 to 255 mm of Hg
 Lower limb 175 to 305 mm of Hg

6. Tourniquet time :
 Initial time 90 minutes ideal is 45 – 60 minutes.
 >2 hours deflate for 5 minutes for reperfusion.
Width of the cuff :
 Standard is 8.5 cm
 15 cm conical shaped produces subsystolic
pressure required to stop detectable flow.
Ischaemic time information to surgeons :
 First 2 hours – half hourly intervals.
 Next at 2.5 hours.
 Next every 15 minutes interval thereafter.
Specification of Tourniquet

7. Patho physiology

8. Pathophysiological effects
 All arterial tourniquets, including the new
automatic devices, can be associated with
complications ranging from the minor and self-
limiting to the debilitating and even fatal.
 Systemic effects are usually related to inflation
and deflation of the tourniquet
 local effects and complications may result from
either direct pressure to the underlying tissues or
ischaemia in tissues distal to the tourniquet.

9. NERVE INJURY
 most common complications associated with
tourniquets and they range from paraesthesia to
paralysis.
 The radial nerve,followed by the ulnar and median
nerves in the upper limb
 the sciatic nerve in the lower limb are most
commonly involved and it would appear that large
diameter nerve fibres are more commonly affected.

10.  Esmarch bandage increases the cause of nerve
injuries and this may explain the fact that nerves
are more susceptible to mechanical pressure
 The effects of nerve compression at the
tourniquet site may make injury caused by
ischaemia or surgical trauma at a more distal site

11. preventive measures
 Tourniquets use only recommended time.
 Check accuracy of the pressure.
 Effective pressure to achieve limb occlusion
pressure.
 Use a cuff that properly fits the extremity.

12. Muscle Injury
 Muscle injury is caused by ischaemia beneath and
distal to the cuff.
 combination of ischaemia and mechanical
deformation of the tissue.
 The extent of the damage is related to the duration of
the ischaemia
 With time the intracellular concentrations of creatine
phosphate, glycogen, ATP and oxygen decrease

13.  Creatine phosphate is depleted by 2 hrs and the
ATP supply is exhausted by 3 hrs.
 Lactate and potassium concentrations and the P
aCO2 increase with increasing duration of
ischaemia
 Intracellular pH decreases – a pH of 6.0 is reached
by 4 hours.
 Intravenous pH in the limb decreases and a pH of

14.  Further ischaemia may produce irreversible muscle
damage.
 After 2 hours at 200 – 300 mmHg, histological
changes
e.g. :inflammatory cells, focal necrosis, regional
necrosis and hyaline degeneration may be seen in
the muscle beneath the cuff
 significant increases in xanthine oxidase activity in
both local and systemic blood

15. post tourniquet syndrome
 The combined effect of muscle ischaemia, oedema
and microvascular congestion
 The affected limb is stiff, pale, weak but not
paralysed, and subjectively numbness without
objective anaesthesia.
 Prolonged bleeding from surgical wound.
 It typically resolves over 1 – 6 weeks

16. Compartment syndrome
 Relative complication of tourniquet.
 External and internal pressures - pain.
 Tense skin, swelling, weakness, parasthesia.
 Absent pulse – irreversible paralysis.
Causes & prevention :
 Trauma or surgery,  time,  pH.
  capillary permeability, Prolongation of clotting.
 Preoperative evaluation
 Time < 90 minutes.

17.  Routine tourniquet use results in weakness and
delayed post operative recovery.
 Greater pressures produce greater functional
impairment.
 Fast twitch fibres are affected more than slow twitch
fibres.
 Wide, properly fitting cuffs require lower inflation
pressures, which may reduce muscle injury

18. Preventive measures
 Should it be necessary to use a tourniquet for
longer than 2 hours
 it is recommended that the limb be reperfused
periodically to allow for metabolic recovery of the
muscle and maintenance of ATP levels.
 Recommendations vary from 10 minutes Hourly
to 15 – 20 minutes every 2 hours

19. VASCULAR INJURY
 Vascular injuries are rare
 They are usually associated with peripheral
vascular disease and fractures of atheromatous
plaques by pressure
 plaque dislodgement
 thrombosis due to lack of blood flow

20. SKIN INJURY
 Skin injuries are uncommon. Esmarch bandages twist
and stretch the skin
 while pressure necrosis and shearing have been
described with pneumatic tourniquets because of
inadequate padding or improper application.
 Chemical burns have been reported with alcohol based
cleansing solutions held against the skin under pressure
 friction burns from the movement of a fully inflated
tourniquet over bare skin

21. HAEMATOMAS/ BLEEDING
 Because of tourniquet inflation, bleeders may not be
identified intraoperatively.
 Once the tourniquet is released, a haematoma may
develop or there may be a potential for acute blood loss
superimposed on the haemodynamic changes of
tourniquet release
 tourniquet release for haemostasis has actually been
shown to increase bleeding
 Haematomas, arterial injuries and a compartment
syndrome may all result in a delayed return of blood flow

22. TOURNIQUET FAILURE
 Bleeding may occur despite a properly applied and
inflated tourniquet, in a patient with noncalcified vessels.
 This is the phenomenon of tourniquet ooze.
 Blood bypasses the tourniquet through the medulla of the
humerus or femur. It typically starts about 30 minutes after
tourniquet inflation .
 Increasing the tourniquet pressure does not help
 Other causes of inadequate haemostasis include arterial
and venous leakage due to inadequate pressure,
calcified, incompressible vessels and inadequate

23. Systemic effects
CARDIO VASCULAR SYSTEM:
 Cardiovascular features are related to all stages of
tourniquet use, from exsanguination to inflation,
maintenance and deflation.
 Limb exsanguination and subsequent tourniquet
inflation increase blood volume and systemic vascular
resistance.
 CVP increases by up to 14 – 15 cmH2 O and blood
volume by up to 800 ml following exsanguination of
both legs.
 The changes in CVP and BP may be transient or may
be maintained until tourniquet release.

24. Tourniquet pain
 Approximately 30 – 60 minutes after tourniquet
inflation, heart rate and blood pressure increase –
this is “tourniquet pain”.
 An awake patient will complain of a vague, dull pain
that be-comes so severe as to be unbearable.
 It will occur despite an adequate sensory level.
 The incidence increases with increasing age and
duration of surgery, and with lower limb surgery.

25.  The pain is probably mediated by the unmyelinated, slow
conducting C fibres .
 The A-delta fibres are blocked by mechanical compression
after about 30 minutes, while the C fibres continue to
function.
 methods used to try to decrease the incidence of pain
include the addition of adrenaline to the local anaesthetic,
the type of local anaesthetic addition of clonidine or
morphine and alteration of the dose of local anaesthetic
 The onset of “tourniquet pain” has been delayed by the
application of EMLA cream to the tourniquet site and by

26.  With tourniquet deflation, CVP and MAP decrease,
reaching a maximum at 3 minutes and taking
approximately 15 minutes to return to normal.
 The decrease is a result of the combination of a shift of the
blood volume back into the limb, a post – ischaemic
reactive hyperaemia, bleeding from nonligated vessels
and washout of metabolites from the ischaemic areas into
the systemic circulation .
 The cardiac index increases to compensate, mainly by an
increase in the myocardial inotropic state
 The mean decrease in systolic blood pressure is 14 – 19
mmHg and the mean increase in heart rate is 6 – 12

27. RESPIRATORY EFFECTS
 As the tourniquet is deflated and the limb reperfuses,
CO2 And metabolites, e.g. lactate, are returned to the
systemic circulation.
 The end tidal CO2(ETCO2) increases by 0.75 – 18
mmHg– the lower limb > upperlimb and men
>women, because of a man’s greater muscle bulk

28.  The ETCO 2 peaks at 1 – 3 minutes, returning to
baseline at 10 – 13 minutes in a spontaneously
breathing patient .
 The increase in ETCO 2 will be prolonged in
mechanically ventilated patients unless the
minute volume is increased.
 The mixed venous saturation decreases
transiently, but a drop in the arterial saturation is
unusual

29. CEREBRAL
CIRCULATORY
EFFECTS
 Middle cerebral artery flow increases after tourniquet
deflation, related to the increased ETCO 2
 This increase is larger with lower limb surgery than with
upper limb
 Patients with reduced intracranial compliance may be at
higher risk for adverse effects related to the increase in
cerebral blood flow
 Maintenance of normocapnia prevents the increase in

30. HAEMATOLOGICAL EFFECTS
 The tourniquet causes changes in both coagulability and
fibrinolysis.
 Tissue damage induces coagulation factors and activates
platelets. Pain (surgical and tourniquet) provokes
catecholamine release, exacerbating the state of
hypercoagulability
 Tissue ischaemia causes tissue plasminogen activator
release, activating the antithrombin III and
thrombomodulin – protein C anticoagulant system in the
affected limb

31.  Patients at high risk for deep vein thrombosis (DVT)
and pulmonary embolism include those with lower
limb trauma, prolonged immobilisation (>3 days ) or a
history of DVT’s.
 Venous embolism is common after tourniquet
deflation.
 The embolus may consist of air, marrow contents,
clot or cement.
 increased incidence of pulmonary emboli in total

32. Sickle cell Haemoglobinopathy
 Sickling is predisposed to by circulatory stasis,
acidosis and hypoxaemia, all of which happen with
the use of a tourniquet.
 Systemic release of anaerobic metabolic products
with cuff deflation may also induce sickling.
 Intravascular sickling may therefore theoretically
occur with tourniquet use in susceptible patients.

33. TEMPERATURE CHANGES
 In both adults and children, core temperature
increases during tourniquet use
 Tourniquet inflation decreases heat transfer from the
central to peripheral compartment, decreases the
surface area available for heat loss and decreases
the heat loss from the distal skin, allowing the
temperature to rise.


34.  The increase in temperature may sometimes be
larger than predicted, slow release of ischaemic
metabolites, which raise the temperature, may
occur via the bone
 In children the temperature may rise by as much
as 1 – 1.7 oC After cuff deflation, a “redistribution
hypothermia” may occur as the cold extremity is
reperfused

35. METABOLIC CHANGES
 With reperfusion of the affected limb, potassium, lactate,
CO2 and other ischaemic metabolites are washed into
the systemic circulation.
 Potassium and lactate concentrations increase for
approx. 30 min and pH decreases transiently.
 Oxygen consumption (VO2) increases by 55% and
CO2produc-tion (VCO2) by 80% 2 minutes post release.
 This increase in VO 2 provides the energy needed to
replenish both the high-energy phosphate and oxygen
stores depleted during ischaemia and the energy needed

36. DRUG KINETICS
 Tourniquet inflation isolates the limb from the rest of
the body, altering the volume of distribution,
sequestering drugs in the limb (if given before
inflation), or preventing them from reaching the limb
(if given after inflation)
 To prevent postoperative infection, prophylactic
antibiotics need to reach the tissues in adequate
concentrations before tourniquet inflation – at least 5
minutes is required

37.  Fentanyl and midazolam sequestered in the limb
are released into the systemic circulation after
cuff deflation.
 These increased levels may be clinically
significant, especially in the elderly, and
prolonged post-operative observation (up to 4
hours) is necessary

38. contraindications
1. Peripheral vascular disease
2. Severe trauma to the limb
3. Head injury/ CNS disorder, peripheral neuropathy
4. Severe infection of the limb
5. DVT in the limb
6. Severe arthritic changes/ bony spurs/ previous
fracture of the limb
7. Poor skin condition of the limb
8. Arteriovenous (AV) fistula
9. Lack of appropriate equipment
10. Sickle cell haemoglobinopathy