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 mans 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 DVTs. 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